/* magic values for the inode_only field in btrfs_log_inode: * * LOG_INODE_ALL means to log everything * LOG_INODE_EXISTS means to log just enough to recreate the inode * during log replay
*/ enum {
LOG_INODE_ALL,
LOG_INODE_EXISTS,
};
/* * directory trouble cases * * 1) on rename or unlink, if the inode being unlinked isn't in the fsync * log, we must force a full commit before doing an fsync of the directory * where the unlink was done. * ---> record transid of last unlink/rename per directory * * mkdir foo/some_dir * normal commit * rename foo/some_dir foo2/some_dir * mkdir foo/some_dir * fsync foo/some_dir/some_file * * The fsync above will unlink the original some_dir without recording * it in its new location (foo2). After a crash, some_dir will be gone * unless the fsync of some_file forces a full commit * * 2) we must log any new names for any file or dir that is in the fsync * log. ---> check inode while renaming/linking. * * 2a) we must log any new names for any file or dir during rename * when the directory they are being removed from was logged. * ---> check inode and old parent dir during rename * * 2a is actually the more important variant. With the extra logging * a crash might unlink the old name without recreating the new one * * 3) after a crash, we must go through any directories with a link count * of zero and redo the rm -rf * * mkdir f1/foo * normal commit * rm -rf f1/foo * fsync(f1) * * The directory f1 was fully removed from the FS, but fsync was never * called on f1, only its parent dir. After a crash the rm -rf must * be replayed. This must be able to recurse down the entire * directory tree. The inode link count fixup code takes care of the * ugly details.
*/
/* * stages for the tree walking. The first * stage (0) is to only pin down the blocks we find * the second stage (1) is to make sure that all the inodes * we find in the log are created in the subvolume. * * The last stage is to deal with directories and links and extents * and all the other fun semantics
*/ enum {
LOG_WALK_PIN_ONLY,
LOG_WALK_REPLAY_INODES,
LOG_WALK_REPLAY_DIR_INDEX,
LOG_WALK_REPLAY_ALL,
};
/* * tree logging is a special write ahead log used to make sure that * fsyncs and O_SYNCs can happen without doing full tree commits. * * Full tree commits are expensive because they require commonly * modified blocks to be recowed, creating many dirty pages in the * extent tree an 4x-6x higher write load than ext3. * * Instead of doing a tree commit on every fsync, we use the * key ranges and transaction ids to find items for a given file or directory * that have changed in this transaction. Those items are copied into * a special tree (one per subvolume root), that tree is written to disk * and then the fsync is considered complete. * * After a crash, items are copied out of the log-tree back into the * subvolume tree. Any file data extents found are recorded in the extent * allocation tree, and the log-tree freed. * * The log tree is read three times, once to pin down all the extents it is * using in ram and once, once to create all the inodes logged in the tree * and once to do all the other items.
*/
/* Only meant to be called for subvolume roots and not for log roots. */
ASSERT(btrfs_is_fstree(btrfs_root_id(root)));
/* * We're holding a transaction handle whether we are logging or * replaying a log tree, so we must make sure NOFS semantics apply * because btrfs_alloc_inode() may be triggered and it uses GFP_KERNEL * to allocate an inode, which can recurse back into the filesystem and * attempt a transaction commit, resulting in a deadlock.
*/
nofs_flag = memalloc_nofs_save();
inode = btrfs_iget(objectid, root);
memalloc_nofs_restore(nofs_flag);
return inode;
}
/* * start a sub transaction and setup the log tree * this increments the log tree writer count to make the people * syncing the tree wait for us to finish
*/ staticint start_log_trans(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_log_ctx *ctx)
{ struct btrfs_fs_info *fs_info = root->fs_info; struct btrfs_root *tree_root = fs_info->tree_root; constbool zoned = btrfs_is_zoned(fs_info); int ret = 0; bool created = false;
/* * First check if the log root tree was already created. If not, create * it before locking the root's log_mutex, just to keep lockdep happy.
*/ if (!test_bit(BTRFS_ROOT_HAS_LOG_TREE, &tree_root->state)) {
mutex_lock(&tree_root->log_mutex); if (!fs_info->log_root_tree) {
ret = btrfs_init_log_root_tree(trans, fs_info); if (!ret) {
set_bit(BTRFS_ROOT_HAS_LOG_TREE, &tree_root->state);
created = true;
}
}
mutex_unlock(&tree_root->log_mutex); if (ret) return ret;
}
mutex_lock(&root->log_mutex);
again: if (root->log_root) { int index = (root->log_transid + 1) % 2;
if (btrfs_need_log_full_commit(trans)) {
ret = BTRFS_LOG_FORCE_COMMIT; goto out;
}
if (!root->log_start_pid) {
clear_bit(BTRFS_ROOT_MULTI_LOG_TASKS, &root->state);
root->log_start_pid = current->pid;
} elseif (root->log_start_pid != current->pid) {
set_bit(BTRFS_ROOT_MULTI_LOG_TASKS, &root->state);
}
} else { /* * This means fs_info->log_root_tree was already created * for some other FS trees. Do the full commit not to mix * nodes from multiple log transactions to do sequential * writing.
*/ if (zoned && !created) {
ret = BTRFS_LOG_FORCE_COMMIT; goto out;
}
ret = btrfs_add_log_tree(trans, root); if (ret) goto out;
/* * returns 0 if there was a log transaction running and we were able * to join, or returns -ENOENT if there were not transactions * in progress
*/ staticint join_running_log_trans(struct btrfs_root *root)
{ constbool zoned = btrfs_is_zoned(root->fs_info); int ret = -ENOENT;
if (!test_bit(BTRFS_ROOT_HAS_LOG_TREE, &root->state)) return ret;
mutex_lock(&root->log_mutex);
again: if (root->log_root) { int index = (root->log_transid + 1) % 2;
/* * This either makes the current running log transaction wait * until you call btrfs_end_log_trans() or it makes any future * log transactions wait until you call btrfs_end_log_trans()
*/ void btrfs_pin_log_trans(struct btrfs_root *root)
{
atomic_inc(&root->log_writers);
}
/* * indicate we're done making changes to the log tree * and wake up anyone waiting to do a sync
*/ void btrfs_end_log_trans(struct btrfs_root *root)
{ if (atomic_dec_and_test(&root->log_writers)) { /* atomic_dec_and_test implies a barrier */
cond_wake_up_nomb(&root->log_writer_wait);
}
}
/* * the walk control struct is used to pass state down the chain when * processing the log tree. The stage field tells us which part * of the log tree processing we are currently doing. The others * are state fields used for that specific part
*/ struct walk_control { /* should we free the extent on disk when done? This is used * at transaction commit time while freeing a log tree
*/ int free;
/* pin only walk, we record which extents on disk belong to the * log trees
*/ int pin;
/* what stage of the replay code we're currently in */ int stage;
/* * Ignore any items from the inode currently being processed. Needs * to be set every time we find a BTRFS_INODE_ITEM_KEY.
*/ bool ignore_cur_inode;
/* the root we are currently replaying */ struct btrfs_root *replay_dest;
/* the trans handle for the current replay */ struct btrfs_trans_handle *trans;
/* the function that gets used to process blocks we find in the * tree. Note the extent_buffer might not be up to date when it is * passed in, and it must be checked or read if you need the data * inside it
*/ int (*process_func)(struct btrfs_root *log, struct extent_buffer *eb, struct walk_control *wc, u64 gen, int level);
};
/* * process_func used to pin down extents, write them or wait on them
*/ staticint process_one_buffer(struct btrfs_root *log, struct extent_buffer *eb, struct walk_control *wc, u64 gen, int level)
{ struct btrfs_trans_handle *trans = wc->trans; struct btrfs_fs_info *fs_info = log->fs_info; int ret = 0;
/* * If this fs is mixed then we need to be able to process the leaves to * pin down any logged extents, so we have to read the block.
*/ if (btrfs_fs_incompat(fs_info, MIXED_GROUPS)) { struct btrfs_tree_parent_check check = {
.level = level,
.transid = gen
};
ret = btrfs_read_extent_buffer(eb, &check); if (ret) { if (trans)
btrfs_abort_transaction(trans, ret); else
btrfs_handle_fs_error(fs_info, ret, NULL); return ret;
}
}
if (wc->pin) {
ASSERT(trans != NULL);
ret = btrfs_pin_extent_for_log_replay(trans, eb); if (ret) {
btrfs_abort_transaction(trans, ret); return ret;
}
if (btrfs_buffer_uptodate(eb, gen, 0) &&
btrfs_header_level(eb) == 0) {
ret = btrfs_exclude_logged_extents(eb); if (ret)
btrfs_abort_transaction(trans, ret);
}
} return ret;
}
/* * Item overwrite used by log replay. The given eb, slot and key all refer to * the source data we are copying out. * * The given root is for the tree we are copying into, and path is a scratch * path for use in this function (it should be released on entry and will be * released on exit). * * If the key is already in the destination tree the existing item is * overwritten. If the existing item isn't big enough, it is extended. * If it is too large, it is truncated. * * If the key isn't in the destination yet, a new item is inserted.
*/ staticint overwrite_item(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, struct extent_buffer *eb, int slot, struct btrfs_key *key)
{ int ret;
u32 item_size;
u64 saved_i_size = 0; int save_old_i_size = 0; unsignedlong src_ptr; unsignedlong dst_ptr; struct extent_buffer *dst_eb; int dst_slot; bool inode_item = key->type == BTRFS_INODE_ITEM_KEY;
/* * This is only used during log replay, so the root is always from a * fs/subvolume tree. In case we ever need to support a log root, then * we'll have to clone the leaf in the path, release the path and use * the leaf before writing into the log tree. See the comments at * copy_items() for more details.
*/
ASSERT(btrfs_root_id(root) != BTRFS_TREE_LOG_OBJECTID);
kfree(src_copy); /* * they have the same contents, just return, this saves * us from cowing blocks in the destination tree and doing * extra writes that may not have been done by a previous * sync
*/ if (ret == 0) {
btrfs_release_path(path); return 0;
}
/* * We need to load the old nbytes into the inode so when we * replay the extents we've logged we get the right nbytes.
*/ if (inode_item) { struct btrfs_inode_item *item;
u64 nbytes;
u32 mode;
/* * If this is a directory we need to reset the i_size to * 0 so that we can set it up properly when replaying * the rest of the items in this log.
*/
mode = btrfs_inode_mode(eb, item); if (S_ISDIR(mode))
btrfs_set_inode_size(eb, item, 0);
}
} elseif (inode_item) { struct btrfs_inode_item *item;
u32 mode;
/* * New inode, set nbytes to 0 so that the nbytes comes out * properly when we replay the extents.
*/
item = btrfs_item_ptr(eb, slot, struct btrfs_inode_item);
btrfs_set_inode_nbytes(eb, item, 0);
/* * If this is a directory we need to reset the i_size to 0 so * that we can set it up properly when replaying the rest of * the items in this log.
*/
mode = btrfs_inode_mode(eb, item); if (S_ISDIR(mode))
btrfs_set_inode_size(eb, item, 0);
}
insert:
btrfs_release_path(path); /* try to insert the key into the destination tree */
path->skip_release_on_error = 1;
ret = btrfs_insert_empty_item(trans, root, path,
key, item_size);
path->skip_release_on_error = 0;
/* make sure any existing item is the correct size */ if (ret == -EEXIST || ret == -EOVERFLOW) { const u32 found_size = btrfs_item_size(dst_eb, dst_slot);
/* don't overwrite an existing inode if the generation number * was logged as zero. This is done when the tree logging code * is just logging an inode to make sure it exists after recovery. * * Also, don't overwrite i_size on directories during replay. * log replay inserts and removes directory items based on the * state of the tree found in the subvolume, and i_size is modified * as it goes
*/ if (key->type == BTRFS_INODE_ITEM_KEY && ret == -EEXIST) { struct btrfs_inode_item *src_item; struct btrfs_inode_item *dst_item;
/* * For regular files an ino_size == 0 is used only when * logging that an inode exists, as part of a directory * fsync, and the inode wasn't fsynced before. In this * case don't set the size of the inode in the fs/subvol * tree, otherwise we would be throwing valid data away.
*/ if (S_ISREG(btrfs_inode_mode(eb, src_item)) &&
S_ISREG(btrfs_inode_mode(dst_eb, dst_item)) &&
ino_size != 0)
btrfs_set_inode_size(dst_eb, dst_item, ino_size); goto no_copy;
}
/* replays a single extent in 'eb' at 'slot' with 'key' into the * subvolume 'root'. path is released on entry and should be released * on exit. * * extents in the log tree have not been allocated out of the extent * tree yet. So, this completes the allocation, taking a reference * as required if the extent already exists or creating a new extent * if it isn't in the extent allocation tree yet. * * The extent is inserted into the file, dropping any existing extents * from the file that overlap the new one.
*/ static noinline int replay_one_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, struct extent_buffer *eb, int slot, struct btrfs_key *key)
{ struct btrfs_drop_extents_args drop_args = { 0 }; struct btrfs_fs_info *fs_info = root->fs_info; int found_type;
u64 extent_end;
u64 start = key->offset;
u64 nbytes = 0; struct btrfs_file_extent_item *item; struct btrfs_inode *inode = NULL; unsignedlong size; int ret = 0;
/* * We don't add to the inodes nbytes if we are prealloc or a * hole.
*/ if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
nbytes = 0;
} elseif (found_type == BTRFS_FILE_EXTENT_INLINE) {
size = btrfs_file_extent_ram_bytes(eb, item);
nbytes = btrfs_file_extent_ram_bytes(eb, item);
extent_end = ALIGN(start + size,
fs_info->sectorsize);
} else {
btrfs_err(fs_info, "unexpected extent type=%d root=%llu inode=%llu offset=%llu",
found_type, btrfs_root_id(root), key->objectid, key->offset); return -EUCLEAN;
}
inode = btrfs_iget_logging(key->objectid, root); if (IS_ERR(inode)) return PTR_ERR(inode);
/* * first check to see if we already have this extent in the * file. This must be done before the btrfs_drop_extents run * so we don't try to drop this extent.
*/
ret = btrfs_lookup_file_extent(trans, root, path, btrfs_ino(inode), start, 0);
/* * we already have a pointer to this exact extent, * we don't have to do anything
*/ if (memcmp_extent_buffer(eb, &existing, (unsignedlong)item, sizeof(existing)) == 0) {
btrfs_release_path(path); goto out;
}
}
btrfs_release_path(path);
/* drop any overlapping extents */
drop_args.start = start;
drop_args.end = extent_end;
drop_args.drop_cache = true;
ret = btrfs_drop_extents(trans, root, inode, &drop_args); if (ret) goto out;
/* * Manually record dirty extent, as here we did a shallow * file extent item copy and skip normal backref update, * but modifying extent tree all by ourselves. * So need to manually record dirty extent for qgroup, * as the owner of the file extent changed from log tree * (doesn't affect qgroup) to fs/file tree(affects qgroup)
*/
ret = btrfs_qgroup_trace_extent(trans,
btrfs_file_extent_disk_bytenr(eb, item),
btrfs_file_extent_disk_num_bytes(eb, item)); if (ret < 0) goto out;
if (ins.objectid > 0) {
u64 csum_start;
u64 csum_end;
LIST_HEAD(ordered_sums);
/* * is this extent already allocated in the extent * allocation tree? If so, just add a reference
*/
ret = btrfs_lookup_data_extent(fs_info, ins.objectid,
ins.offset); if (ret < 0) { goto out;
} elseif (ret == 0) { struct btrfs_ref ref = {
.action = BTRFS_ADD_DELAYED_REF,
.bytenr = ins.objectid,
.num_bytes = ins.offset,
.owning_root = btrfs_root_id(root),
.ref_root = btrfs_root_id(root),
};
btrfs_init_data_ref(&ref, key->objectid, offset,
0, false);
ret = btrfs_inc_extent_ref(trans, &ref); if (ret) goto out;
} else { /* * insert the extent pointer in the extent * allocation tree
*/
ret = btrfs_alloc_logged_file_extent(trans,
btrfs_root_id(root),
key->objectid, offset, &ins); if (ret) goto out;
}
btrfs_release_path(path);
ret = btrfs_lookup_csums_list(root->log_root,
csum_start, csum_end - 1,
&ordered_sums, false); if (ret < 0) goto out;
ret = 0; /* * Now delete all existing cums in the csum root that * cover our range. We do this because we can have an * extent that is completely referenced by one file * extent item and partially referenced by another * file extent item (like after using the clone or * extent_same ioctls). In this case if we end up doing * the replay of the one that partially references the * extent first, and we do not do the csum deletion * below, we can get 2 csum items in the csum tree that * overlap each other. For example, imagine our log has * the two following file extent items: * * key (257 EXTENT_DATA 409600) * extent data disk byte 12845056 nr 102400 * extent data offset 20480 nr 20480 ram 102400 * * key (257 EXTENT_DATA 819200) * extent data disk byte 12845056 nr 102400 * extent data offset 0 nr 102400 ram 102400 * * Where the second one fully references the 100K extent * that starts at disk byte 12845056, and the log tree * has a single csum item that covers the entire range * of the extent: * * key (EXTENT_CSUM EXTENT_CSUM 12845056) itemsize 100 * * After the first file extent item is replayed, the * csum tree gets the following csum item: * * key (EXTENT_CSUM EXTENT_CSUM 12865536) itemsize 20 * * Which covers the 20K sub-range starting at offset 20K * of our extent. Now when we replay the second file * extent item, if we do not delete existing csum items * that cover any of its blocks, we end up getting two * csum items in our csum tree that overlap each other: * * key (EXTENT_CSUM EXTENT_CSUM 12845056) itemsize 100 * key (EXTENT_CSUM EXTENT_CSUM 12865536) itemsize 20 * * Which is a problem, because after this anyone trying * to lookup up for the checksum of any block of our * extent starting at an offset of 40K or higher, will * end up looking at the second csum item only, which * does not contain the checksum for any block starting * at offset 40K or higher of our extent.
*/ while (!list_empty(&ordered_sums)) { struct btrfs_ordered_sum *sums; struct btrfs_root *csum_root;
sums = list_first_entry(&ordered_sums, struct btrfs_ordered_sum,
list);
csum_root = btrfs_csum_root(fs_info,
sums->logical); if (!ret)
ret = btrfs_del_csums(trans, csum_root,
sums->logical,
sums->len); if (!ret)
ret = btrfs_csum_file_blocks(trans,
csum_root,
sums);
list_del(&sums->list);
kfree(sums);
} if (ret) goto out;
} else {
btrfs_release_path(path);
}
} elseif (found_type == BTRFS_FILE_EXTENT_INLINE) { /* inline extents are easy, we just overwrite them */
ret = overwrite_item(trans, root, path, eb, slot, key); if (ret) goto out;
}
ret = btrfs_inode_set_file_extent_range(inode, start, extent_end - start); if (ret) goto out;
ret = btrfs_unlink_inode(trans, dir, inode, name); if (ret) return ret; /* * Whenever we need to check if a name exists or not, we check the * fs/subvolume tree. So after an unlink we must run delayed items, so * that future checks for a name during log replay see that the name * does not exists anymore.
*/ return btrfs_run_delayed_items(trans);
}
/* * when cleaning up conflicts between the directory names in the * subvolume, directory names in the log and directory names in the * inode back references, we may have to unlink inodes from directories. * * This is a helper function to do the unlink of a specific directory * item
*/ static noinline int drop_one_dir_item(struct btrfs_trans_handle *trans, struct btrfs_path *path, struct btrfs_inode *dir, struct btrfs_dir_item *di)
{ struct btrfs_root *root = dir->root; struct btrfs_inode *inode; struct fscrypt_str name; struct extent_buffer *leaf; struct btrfs_key location; int ret;
leaf = path->nodes[0];
btrfs_dir_item_key_to_cpu(leaf, di, &location);
ret = read_alloc_one_name(leaf, di + 1, btrfs_dir_name_len(leaf, di), &name); if (ret) return -ENOMEM;
btrfs_release_path(path);
inode = btrfs_iget_logging(location.objectid, root); if (IS_ERR(inode)) {
ret = PTR_ERR(inode);
inode = NULL; goto out;
}
ret = link_to_fixup_dir(trans, root, path, location.objectid); if (ret) goto out;
ret = unlink_inode_for_log_replay(trans, dir, inode, &name);
out:
kfree(name.name); if (inode)
iput(&inode->vfs_inode); return ret;
}
/* * See if a given name and sequence number found in an inode back reference are * already in a directory and correctly point to this inode. * * Returns: < 0 on error, 0 if the directory entry does not exists and 1 if it * exists.
*/ static noinline int inode_in_dir(struct btrfs_root *root, struct btrfs_path *path,
u64 dirid, u64 objectid, u64 index, struct fscrypt_str *name)
{ struct btrfs_dir_item *di; struct btrfs_key location; int ret = 0;
di = btrfs_lookup_dir_index_item(NULL, root, path, dirid,
index, name, 0); if (IS_ERR(di)) {
ret = PTR_ERR(di); goto out;
} elseif (di) {
btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location); if (location.objectid != objectid) goto out;
} else { goto out;
}
btrfs_release_path(path);
di = btrfs_lookup_dir_item(NULL, root, path, dirid, name, 0); if (IS_ERR(di)) {
ret = PTR_ERR(di); goto out;
} elseif (di) {
btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location); if (location.objectid == objectid)
ret = 1;
}
out:
btrfs_release_path(path); return ret;
}
/* * helper function to check a log tree for a named back reference in * an inode. This is used to decide if a back reference that is * found in the subvolume conflicts with what we find in the log. * * inode backreferences may have multiple refs in a single item, * during replay we process one reference at a time, and we don't * want to delete valid links to a file from the subvolume if that * link is also in the log.
*/ static noinline int backref_in_log(struct btrfs_root *log, struct btrfs_key *key,
u64 ref_objectid, conststruct fscrypt_str *name)
{ struct btrfs_path *path; int ret;
path = btrfs_alloc_path(); if (!path) return -ENOMEM;
ret = btrfs_search_slot(NULL, log, key, path, 0, 0); if (ret < 0) { goto out;
} elseif (ret == 1) {
ret = 0; goto out;
}
if (key->type == BTRFS_INODE_EXTREF_KEY)
ret = !!btrfs_find_name_in_ext_backref(path->nodes[0],
path->slots[0],
ref_objectid, name); else
ret = !!btrfs_find_name_in_backref(path->nodes[0],
path->slots[0], name);
out:
btrfs_free_path(path); return ret;
}
/* * Check all the names in this back reference to see if they are in the * log. If so, we allow them to stay otherwise they must be unlinked as * a conflict.
*/
ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
ptr_end = ptr + btrfs_item_size(leaf, path->slots[0]); while (ptr < ptr_end) { struct fscrypt_str victim_name; struct btrfs_inode_ref *victim_ref; int ret;
victim_ref = (struct btrfs_inode_ref *)ptr;
ret = read_alloc_one_name(leaf, (victim_ref + 1),
btrfs_inode_ref_name_len(leaf, victim_ref),
&victim_name); if (ret) return ret;
ret = backref_in_log(log_root, search_key, parent_objectid, &victim_name); if (ret) {
kfree(victim_name.name); if (ret < 0) return ret;
ptr = (unsignedlong)(victim_ref + 1) + victim_name.len; continue;
}
again: /* Search old style refs */
search_key.objectid = inode_objectid;
search_key.type = BTRFS_INODE_REF_KEY;
search_key.offset = parent_objectid;
ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0); if (ret < 0) { return ret;
} elseif (ret == 0) { /* * Are we trying to overwrite a back ref for the root directory? * If so, we're done.
*/ if (search_key.objectid == search_key.offset) return 1;
ret = read_alloc_one_name(eb, ref + 1, btrfs_inode_ref_name_len(eb, ref),
name); if (ret) return ret;
if (index)
*index = btrfs_inode_ref_index(eb, ref);
return 0;
}
/* * Take an inode reference item from the log tree and iterate all names from the * inode reference item in the subvolume tree with the same key (if it exists). * For any name that is not in the inode reference item from the log tree, do a * proper unlink of that name (that is, remove its entry from the inode * reference item and both dir index keys).
*/ staticint unlink_old_inode_refs(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, struct btrfs_inode *inode, struct extent_buffer *log_eb, int log_slot, struct btrfs_key *key)
{ int ret; unsignedlong ref_ptr; unsignedlong ref_end; struct extent_buffer *eb;
again:
btrfs_release_path(path);
ret = btrfs_search_slot(NULL, root, key, path, 0, 0); if (ret > 0) {
ret = 0; goto out;
} if (ret < 0) goto out;
/* * replay one inode back reference item found in the log tree. * eb, slot and key refer to the buffer and key found in the log tree. * root is the destination we are replaying into, and path is for temp * use by this function. (it should be released on return).
*/ static noinline int add_inode_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_root *log, struct btrfs_path *path, struct extent_buffer *eb, int slot, struct btrfs_key *key)
{ struct btrfs_inode *dir = NULL; struct btrfs_inode *inode = NULL; unsignedlong ref_ptr; unsignedlong ref_end; struct fscrypt_str name = { 0 }; int ret; constbool is_extref_item = (key->type == BTRFS_INODE_EXTREF_KEY);
u64 parent_objectid;
u64 inode_objectid;
u64 ref_index = 0; int ref_struct_size;
/* * it is possible that we didn't log all the parent directories * for a given inode. If we don't find the dir, just don't * copy the back ref in. The link count fixup code will take * care of the rest
*/
dir = btrfs_iget_logging(parent_objectid, root); if (IS_ERR(dir)) {
ret = PTR_ERR(dir); if (ret == -ENOENT)
ret = 0;
dir = NULL; goto out;
}
inode = btrfs_iget_logging(inode_objectid, root); if (IS_ERR(inode)) {
ret = PTR_ERR(inode);
inode = NULL; goto out;
}
while (ref_ptr < ref_end) { if (is_extref_item) {
ret = extref_get_fields(eb, ref_ptr, &name,
&ref_index, &parent_objectid); if (ret) goto out; /* * parent object can change from one array * item to another.
*/ if (!dir) {
dir = btrfs_iget_logging(parent_objectid, root); if (IS_ERR(dir)) {
ret = PTR_ERR(dir);
dir = NULL; /* * A new parent dir may have not been * logged and not exist in the subvolume * tree, see the comment above before * the loop when getting the first * parent dir.
*/ if (ret == -ENOENT) { /* * The next extref may refer to * another parent dir that * exists, so continue.
*/
ret = 0; goto next;
} goto out;
}
}
} else {
ret = ref_get_fields(eb, ref_ptr, &name, &ref_index); if (ret) goto out;
}
ret = inode_in_dir(root, path, btrfs_ino(dir), btrfs_ino(inode),
ref_index, &name); if (ret < 0) { goto out;
} elseif (ret == 0) { /* * look for a conflicting back reference in the * metadata. if we find one we have to unlink that name * of the file before we add our new link. Later on, we * overwrite any existing back reference, and we don't * want to create dangling pointers in the directory.
*/
ret = __add_inode_ref(trans, root, path, log, dir, inode,
inode_objectid, parent_objectid,
ref_index, &name); if (ret) { if (ret == 1)
ret = 0; goto out;
}
/* insert our name */
ret = btrfs_add_link(trans, dir, inode, &name, 0, ref_index); if (ret) goto out;
ret = btrfs_update_inode(trans, inode); if (ret) goto out;
} /* Else, ret == 1, we already have a perfect match, we're done. */
/* * Before we overwrite the inode reference item in the subvolume tree * with the item from the log tree, we must unlink all names from the * parent directory that are in the subvolume's tree inode reference * item, otherwise we end up with an inconsistent subvolume tree where * dir index entries exist for a name but there is no inode reference * item with the same name.
*/
ret = unlink_old_inode_refs(trans, root, path, inode, eb, slot, key); if (ret) goto out;
/* finally write the back reference in the inode */
ret = overwrite_item(trans, root, path, eb, slot, key);
out:
btrfs_release_path(path);
kfree(name.name); if (dir)
iput(&dir->vfs_inode); if (inode)
iput(&inode->vfs_inode); return ret;
}
if (key.offset == 0) break; if (path->slots[0] > 0) {
path->slots[0]--; goto process_slot;
}
key.offset--;
btrfs_release_path(path);
}
btrfs_release_path(path);
return nlink;
}
/* * There are a few corners where the link count of the file can't * be properly maintained during replay. So, instead of adding * lots of complexity to the log code, we just scan the backrefs * for any file that has been through replay. * * The scan will update the link count on the inode to reflect the * number of back refs found. If it goes down to zero, the iput * will free the inode.
*/ static noinline int fixup_inode_link_count(struct btrfs_trans_handle *trans, struct btrfs_inode *inode)
{ struct btrfs_root *root = inode->root; struct btrfs_path *path; int ret;
u64 nlink = 0; const u64 ino = btrfs_ino(inode);
path = btrfs_alloc_path(); if (!path) return -ENOMEM;
ret = count_inode_refs(inode, path); if (ret < 0) goto out;
nlink = ret;
ret = count_inode_extrefs(inode, path); if (ret < 0) goto out;
nlink += ret;
ret = 0;
if (nlink != inode->vfs_inode.i_nlink) {
set_nlink(&inode->vfs_inode, nlink);
ret = btrfs_update_inode(trans, inode); if (ret) goto out;
} if (S_ISDIR(inode->vfs_inode.i_mode))
inode->index_cnt = (u64)-1;
if (inode->vfs_inode.i_nlink == 0) { if (S_ISDIR(inode->vfs_inode.i_mode)) {
ret = replay_dir_deletes(trans, root, NULL, path, ino, true); if (ret) goto out;
}
ret = btrfs_insert_orphan_item(trans, root, ino); if (ret == -EEXIST)
ret = 0;
}
out:
btrfs_free_path(path); return ret;
}
static noinline int fixup_inode_link_counts(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path)
{ int ret; struct btrfs_key key;
ret = btrfs_del_item(trans, root, path); if (ret) break;
btrfs_release_path(path);
inode = btrfs_iget_logging(key.offset, root); if (IS_ERR(inode)) {
ret = PTR_ERR(inode); break;
}
ret = fixup_inode_link_count(trans, inode);
iput(&inode->vfs_inode); if (ret) break;
/* * fixup on a directory may create new entries, * make sure we always look for the highset possible * offset
*/
key.offset = (u64)-1;
}
btrfs_release_path(path); return ret;
}
/* * record a given inode in the fixup dir so we can check its link * count when replay is done. The link count is incremented here * so the inode won't go away until we check it
*/ static noinline int link_to_fixup_dir(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path,
u64 objectid)
{ struct btrfs_key key; int ret = 0; struct btrfs_inode *inode; struct inode *vfs_inode;
inode = btrfs_iget_logging(objectid, root); if (IS_ERR(inode)) return PTR_ERR(inode);
ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
btrfs_release_path(path); if (ret == 0) { if (!vfs_inode->i_nlink)
set_nlink(vfs_inode, 1); else
inc_nlink(vfs_inode);
ret = btrfs_update_inode(trans, inode); if (ret)
btrfs_abort_transaction(trans, ret);
} elseif (ret == -EEXIST) {
ret = 0;
}
iput(vfs_inode);
return ret;
}
/* * when replaying the log for a directory, we only insert names * for inodes that actually exist. This means an fsync on a directory * does not implicitly fsync all the new files in it
*/ static noinline int insert_one_name(struct btrfs_trans_handle *trans, struct btrfs_root *root,
u64 dirid, u64 index, conststruct fscrypt_str *name, struct btrfs_key *location)
{ struct btrfs_inode *inode; struct btrfs_inode *dir; int ret;
inode = btrfs_iget_logging(location->objectid, root); if (IS_ERR(inode)) return PTR_ERR(inode);
dir = btrfs_iget_logging(dirid, root); if (IS_ERR(dir)) {
iput(&inode->vfs_inode); return PTR_ERR(dir);
}
ret = btrfs_add_link(trans, dir, inode, name, 1, index);
/* * take a single entry in a log directory item and replay it into * the subvolume. * * if a conflicting item exists in the subdirectory already, * the inode it points to is unlinked and put into the link count * fix up tree. * * If a name from the log points to a file or directory that does * not exist in the FS, it is skipped. fsyncs on directories * do not force down inodes inside that directory, just changes to the * names or unlinks in a directory. * * Returns < 0 on error, 0 if the name wasn't replayed (dentry points to a * non-existing inode) and 1 if the name was replayed.
*/ static noinline int replay_one_name(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, struct extent_buffer *eb, struct btrfs_dir_item *di, struct btrfs_key *key)
{ struct fscrypt_str name = { 0 }; struct btrfs_dir_item *dir_dst_di; struct btrfs_dir_item *index_dst_di; bool dir_dst_matches = false; bool index_dst_matches = false; struct btrfs_key log_key; struct btrfs_key search_key; struct btrfs_inode *dir;
u8 log_flags; bool exists; int ret; bool update_size = true; bool name_added = false;
dir = btrfs_iget_logging(key->objectid, root); if (IS_ERR(dir)) return PTR_ERR(dir);
ret = read_alloc_one_name(eb, di + 1, btrfs_dir_name_len(eb, di), &name); if (ret) goto out;
log_flags = btrfs_dir_flags(eb, di);
btrfs_dir_item_key_to_cpu(eb, di, &log_key);
ret = btrfs_lookup_inode(trans, root, path, &log_key, 0);
btrfs_release_path(path); if (ret < 0) goto out;
exists = (ret == 0);
ret = 0;
if (dir_dst_matches && index_dst_matches) {
ret = 0;
update_size = false; goto out;
}
/* * Check if the inode reference exists in the log for the given name, * inode and parent inode
*/
search_key.objectid = log_key.objectid;
search_key.type = BTRFS_INODE_REF_KEY;
search_key.offset = key->objectid;
ret = backref_in_log(root->log_root, &search_key, 0, &name); if (ret < 0) { goto out;
} elseif (ret) { /* The dentry will be added later. */
ret = 0;
update_size = false; goto out;
}
search_key.objectid = log_key.objectid;
search_key.type = BTRFS_INODE_EXTREF_KEY;
search_key.offset = btrfs_extref_hash(key->objectid, name.name, name.len);
ret = backref_in_log(root->log_root, &search_key, key->objectid, &name); if (ret < 0) { goto out;
} elseif (ret) { /* The dentry will be added later. */
ret = 0;
update_size = false; goto out;
}
btrfs_release_path(path);
ret = insert_one_name(trans, root, key->objectid, key->offset,
&name, &log_key); if (ret && ret != -ENOENT && ret != -EEXIST) goto out; if (!ret)
name_added = true;
update_size = false;
ret = 0;
out: if (!ret && update_size) {
btrfs_i_size_write(dir, dir->vfs_inode.i_size + name.len * 2);
ret = btrfs_update_inode(trans, dir);
}
kfree(name.name);
iput(&dir->vfs_inode); if (!ret && name_added)
ret = 1; return ret;
}
/* Replay one dir item from a BTRFS_DIR_INDEX_KEY key. */ static noinline int replay_one_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, struct extent_buffer *eb, int slot, struct btrfs_key *key)
{ int ret; struct btrfs_dir_item *di;
/* We only log dir index keys, which only contain a single dir item. */
ASSERT(key->type == BTRFS_DIR_INDEX_KEY);
di = btrfs_item_ptr(eb, slot, struct btrfs_dir_item);
ret = replay_one_name(trans, root, path, eb, di, key); if (ret < 0) return ret;
/* * If this entry refers to a non-directory (directories can not have a * link count > 1) and it was added in the transaction that was not * committed, make sure we fixup the link count of the inode the entry * points to. Otherwise something like the following would result in a * directory pointing to an inode with a wrong link that does not account * for this dir entry: * * mkdir testdir * touch testdir/foo * touch testdir/bar * sync * * ln testdir/bar testdir/bar_link * ln testdir/foo testdir/foo_link * xfs_io -c "fsync" testdir/bar * * <power failure> * * mount fs, log replay happens * * File foo would remain with a link count of 1 when it has two entries * pointing to it in the directory testdir. This would make it impossible * to ever delete the parent directory has it would result in stale * dentries that can never be deleted.
*/ if (ret == 1 && btrfs_dir_ftype(eb, di) != BTRFS_FT_DIR) { struct btrfs_path *fixup_path; struct btrfs_key di_key;
fixup_path = btrfs_alloc_path(); if (!fixup_path) return -ENOMEM;
/* * directory replay has two parts. There are the standard directory * items in the log copied from the subvolume, and range items * created in the log while the subvolume was logged. * * The range items tell us which parts of the key space the log * is authoritative for. During replay, if a key in the subvolume * directory is in a logged range item, but not actually in the log * that means it was deleted from the directory before the fsync * and should be removed.
*/ static noinline int find_dir_range(struct btrfs_root *root, struct btrfs_path *path,
u64 dirid,
u64 *start_ret, u64 *end_ret)
{ struct btrfs_key key;
u64 found_end; struct btrfs_dir_log_item *item; int ret; int nritems;
if (*start_ret >= key.offset && *start_ret <= found_end) {
ret = 0;
*start_ret = key.offset;
*end_ret = found_end; goto out;
}
ret = 1;
next: /* check the next slot in the tree to see if it is a valid item */
nritems = btrfs_header_nritems(path->nodes[0]);
path->slots[0]++; if (path->slots[0] >= nritems) {
ret = btrfs_next_leaf(root, path); if (ret) goto out;
}
/* * this looks for a given directory item in the log. If the directory * item is not in the log, the item is removed and the inode it points * to is unlinked
*/ static noinline int check_item_in_log(struct btrfs_trans_handle *trans, struct btrfs_root *log, struct btrfs_path *path, struct btrfs_path *log_path, struct btrfs_inode *dir, struct btrfs_key *dir_key)
{ struct btrfs_root *root = dir->root; int ret; struct extent_buffer *eb; int slot; struct btrfs_dir_item *di; struct fscrypt_str name = { 0 }; struct btrfs_inode *inode = NULL; struct btrfs_key location;
/* * Currently we only log dir index keys. Even if we replay a log created * by an older kernel that logged both dir index and dir item keys, all * we need to do is process the dir index keys, we (and our caller) can * safely ignore dir item keys (key type BTRFS_DIR_ITEM_KEY).
*/
ASSERT(dir_key->type == BTRFS_DIR_INDEX_KEY);
eb = path->nodes[0];
slot = path->slots[0];
di = btrfs_item_ptr(eb, slot, struct btrfs_dir_item);
ret = read_alloc_one_name(eb, di + 1, btrfs_dir_name_len(eb, di), &name); if (ret) goto out;
if (log) { struct btrfs_dir_item *log_di;
log_di = btrfs_lookup_dir_index_item(trans, log, log_path,
dir_key->objectid,
dir_key->offset, &name, 0); if (IS_ERR(log_di)) {
ret = PTR_ERR(log_di); goto out;
} elseif (log_di) { /* The dentry exists in the log, we have nothing to do. */
ret = 0; goto out;
}
}
ret = link_to_fixup_dir(trans, root, path, location.objectid); if (ret) goto out;
inc_nlink(&inode->vfs_inode);
ret = unlink_inode_for_log_replay(trans, dir, inode, &name); /* * Unlike dir item keys, dir index keys can only have one name (entry) in * them, as there are no key collisions since each key has a unique offset * (an index number), so we're done.
*/
out:
btrfs_release_path(path);
btrfs_release_path(log_path);
kfree(name.name); if (inode)
iput(&inode->vfs_inode); return ret;
}
staticint replay_xattr_deletes(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_root *log, struct btrfs_path *path, const u64 ino)
{ struct btrfs_key search_key; struct btrfs_path *log_path; int i; int nritems; int ret;
log_path = btrfs_alloc_path(); if (!log_path) return -ENOMEM;
search_key.objectid = ino;
search_key.type = BTRFS_XATTR_ITEM_KEY;
search_key.offset = 0;
again:
ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0); if (ret < 0) goto out;
process_leaf:
nritems = btrfs_header_nritems(path->nodes[0]); for (i = path->slots[0]; i < nritems; i++) { struct btrfs_key key; struct btrfs_dir_item *di; struct btrfs_dir_item *log_di;
u32 total_size;
u32 cur;
btrfs_item_key_to_cpu(path->nodes[0], &key, i); if (key.objectid != ino || key.type != BTRFS_XATTR_ITEM_KEY) {
ret = 0; goto out;
}
di = btrfs_item_ptr(path->nodes[0], i, struct btrfs_dir_item);
total_size = btrfs_item_size(path->nodes[0], i);
cur = 0; while (cur < total_size) {
u16 name_len = btrfs_dir_name_len(path->nodes[0], di);
u16 data_len = btrfs_dir_data_len(path->nodes[0], di);
u32 this_len = sizeof(*di) + name_len + data_len; char *name;
name = kmalloc(name_len, GFP_NOFS); if (!name) {
ret = -ENOMEM; goto out;
}
read_extent_buffer(path->nodes[0], name,
(unsignedlong)(di + 1), name_len);
log_di = btrfs_lookup_xattr(NULL, log, log_path, ino,
name, name_len, 0);
btrfs_release_path(log_path); if (!log_di) { /* Doesn't exist in log tree, so delete it. */
btrfs_release_path(path);
di = btrfs_lookup_xattr(trans, root, path, ino,
name, name_len, -1);
kfree(name); if (IS_ERR(di)) {
ret = PTR_ERR(di); goto out;
}
ASSERT(di);
ret = btrfs_delete_one_dir_name(trans, root,
path, di); if (ret) goto out;
btrfs_release_path(path);
search_key = key; goto again;
}
kfree(name); if (IS_ERR(log_di)) {
ret = PTR_ERR(log_di); goto out;
}
cur += this_len;
di = (struct btrfs_dir_item *)((char *)di + this_len);
}
}
ret = btrfs_next_leaf(root, path); if (ret > 0)
ret = 0; elseif (ret == 0) goto process_leaf;
out:
btrfs_free_path(log_path);
btrfs_release_path(path); return ret;
}
/* * deletion replay happens before we copy any new directory items * out of the log or out of backreferences from inodes. It * scans the log to find ranges of keys that log is authoritative for, * and then scans the directory to find items in those ranges that are * not present in the log. * * Anything we don't find in the log is unlinked and removed from the * directory.
*/ static noinline int replay_dir_deletes(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_root *log, struct btrfs_path *path,
u64 dirid, bool del_all)
{
u64 range_start;
u64 range_end; int ret = 0; struct btrfs_key dir_key; struct btrfs_key found_key; struct btrfs_path *log_path; struct btrfs_inode *dir;
dir = btrfs_iget_logging(dirid, root); /* * It isn't an error if the inode isn't there, that can happen because * we replay the deletes before we copy in the inode item from the log.
*/ if (IS_ERR(dir)) {
btrfs_free_path(log_path);
ret = PTR_ERR(dir); if (ret == -ENOENT)
ret = 0; return ret;
}
range_start = 0;
range_end = 0; while (1) { if (del_all)
range_end = (u64)-1; else {
ret = find_dir_range(log, path, dirid,
&range_start, &range_end); if (ret < 0) goto out; elseif (ret > 0) break;
}
dir_key.offset = range_start; while (1) { int nritems;
ret = btrfs_search_slot(NULL, root, &dir_key, path,
0, 0); if (ret < 0) goto out;
nritems = btrfs_header_nritems(path->nodes[0]); if (path->slots[0] >= nritems) {
ret = btrfs_next_leaf(root, path); if (ret == 1) break; elseif (ret < 0) goto out;
}
btrfs_item_key_to_cpu(path->nodes[0], &found_key,
path->slots[0]); if (found_key.objectid != dirid ||
found_key.type != dir_key.type) {
ret = 0; goto out;
}
if (found_key.offset > range_end) break;
ret = check_item_in_log(trans, log, path,
log_path, dir,
&found_key); if (ret) goto out; if (found_key.offset == (u64)-1) break;
dir_key.offset = found_key.offset + 1;
}
btrfs_release_path(path); if (range_end == (u64)-1) break;
range_start = range_end + 1;
}
ret = 0;
out:
btrfs_release_path(path);
btrfs_free_path(log_path);
iput(&dir->vfs_inode); return ret;
}
/* * the process_func used to replay items from the log tree. This * gets called in two different stages. The first stage just looks * for inodes and makes sure they are all copied into the subvolume. * * The second stage copies all the other item types from the log into * the subvolume. The two stage approach is slower, but gets rid of * lots of complexity around inodes referencing other inodes that exist * only in the log (references come from either directory items or inode * back refs).
*/ staticint replay_one_buffer(struct btrfs_root *log, struct extent_buffer *eb, struct walk_control *wc, u64 gen, int level)
{ int nritems; struct btrfs_tree_parent_check check = {
.transid = gen,
.level = level
}; struct btrfs_path *path; struct btrfs_root *root = wc->replay_dest; struct btrfs_key key; int i; int ret;
if (level != 0) return 0;
ret = btrfs_read_extent_buffer(eb, &check); if (ret) return ret;
path = btrfs_alloc_path(); if (!path) return -ENOMEM;
nritems = btrfs_header_nritems(eb); for (i = 0; i < nritems; i++) { struct btrfs_inode_item *inode_item;
btrfs_item_key_to_cpu(eb, &key, i);
if (key.type == BTRFS_INODE_ITEM_KEY) {
inode_item = btrfs_item_ptr(eb, i, struct btrfs_inode_item); /* * An inode with no links is either: * * 1) A tmpfile (O_TMPFILE) that got fsync'ed and never * got linked before the fsync, skip it, as replaying * it is pointless since it would be deleted later. * We skip logging tmpfiles, but it's always possible * we are replaying a log created with a kernel that * used to log tmpfiles; * * 2) A non-tmpfile which got its last link deleted * while holding an open fd on it and later got * fsynced through that fd. We always log the * parent inodes when inode->last_unlink_trans is * set to the current transaction, so ignore all the * inode items for this inode. We will delete the * inode when processing the parent directory with * replay_dir_deletes().
*/ if (btrfs_inode_nlink(eb, inode_item) == 0) {
wc->ignore_cur_inode = true; continue;
} else {
wc->ignore_cur_inode = false;
}
}
/* Inode keys are done during the first stage. */ if (key.type == BTRFS_INODE_ITEM_KEY &&
wc->stage == LOG_WALK_REPLAY_INODES) {
u32 mode;
ret = replay_xattr_deletes(wc->trans, root, log, path, key.objectid); if (ret) break;
mode = btrfs_inode_mode(eb, inode_item); if (S_ISDIR(mode)) {
ret = replay_dir_deletes(wc->trans, root, log, path,
key.objectid, false); if (ret) break;
}
ret = overwrite_item(wc->trans, root, path,
eb, i, &key); if (ret) break;
/* * Before replaying extents, truncate the inode to its * size. We need to do it now and not after log replay * because before an fsync we can have prealloc extents * added beyond the inode's i_size. If we did it after, * through orphan cleanup for example, we would drop * those prealloc extents just after replaying them.
*/ if (S_ISREG(mode)) { struct btrfs_drop_extents_args drop_args = { 0 }; struct btrfs_inode *inode;
u64 from;
inode = btrfs_iget_logging(key.objectid, root); if (IS_ERR(inode)) {
ret = PTR_ERR(inode); break;
}
from = ALIGN(i_size_read(&inode->vfs_inode),
root->fs_info->sectorsize);
drop_args.start = from;
drop_args.end = (u64)-1;
drop_args.drop_cache = true;
ret = btrfs_drop_extents(wc->trans, root, inode,
&drop_args); if (!ret) {
inode_sub_bytes(&inode->vfs_inode,
drop_args.bytes_found); /* Update the inode's nbytes. */
ret = btrfs_update_inode(wc->trans, inode);
}
iput(&inode->vfs_inode); if (ret) break;
}
ret = link_to_fixup_dir(wc->trans, root,
path, key.objectid); if (ret) break;
}
if (wc->ignore_cur_inode) continue;
if (key.type == BTRFS_DIR_INDEX_KEY &&
wc->stage == LOG_WALK_REPLAY_DIR_INDEX) {
ret = replay_one_dir_item(wc->trans, root, path,
eb, i, &key); if (ret) break;
}
if (wc->stage < LOG_WALK_REPLAY_ALL) continue;
/* these keys are simply copied */ if (key.type == BTRFS_XATTR_ITEM_KEY) {
ret = overwrite_item(wc->trans, root, path,
eb, i, &key); if (ret) break;
} elseif (key.type == BTRFS_INODE_REF_KEY ||
key.type == BTRFS_INODE_EXTREF_KEY) {
ret = add_inode_ref(wc->trans, root, log, path,
eb, i, &key); if (ret) break;
} elseif (key.type == BTRFS_EXTENT_DATA_KEY) {
ret = replay_one_extent(wc->trans, root, path,
eb, i, &key); if (ret) break;
} /* * We don't log BTRFS_DIR_ITEM_KEY keys anymore, only the * BTRFS_DIR_INDEX_KEY items which we use to derive the * BTRFS_DIR_ITEM_KEY items. If we are replaying a log from an * older kernel with such keys, ignore them.
*/
}
btrfs_free_path(path); return ret;
}
/* * Correctly adjust the reserved bytes occupied by a log tree extent buffer
*/ staticint unaccount_log_buffer(struct btrfs_fs_info *fs_info, u64 start)
{ struct btrfs_block_group *cache;
cache = btrfs_lookup_block_group(fs_info, start); if (!cache) {
btrfs_err(fs_info, "unable to find block group for %llu", start); return -ENOENT;
}
static noinline int walk_up_log_tree(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, int *level, struct walk_control *wc)
{ int i; int slot; int ret;
for (i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
slot = path->slots[i]; if (slot + 1 < btrfs_header_nritems(path->nodes[i])) {
path->slots[i]++;
*level = i;
WARN_ON(*level == 0); return 0;
} else {
ret = wc->process_func(root, path->nodes[*level], wc,
btrfs_header_generation(path->nodes[*level]),
*level); if (ret) return ret;
if (wc->free) {
ret = clean_log_buffer(trans, path->nodes[*level]); if (ret) return ret;
}
free_extent_buffer(path->nodes[*level]);
path->nodes[*level] = NULL;
*level = i + 1;
}
} return 1;
}
/* * drop the reference count on the tree rooted at 'snap'. This traverses * the tree freeing any blocks that have a ref count of zero after being * decremented.
*/ staticint walk_log_tree(struct btrfs_trans_handle *trans, struct btrfs_root *log, struct walk_control *wc)
{ int ret = 0; int wret; int level; struct btrfs_path *path; int orig_level;
path = btrfs_alloc_path(); if (!path) return -ENOMEM;
while (1) {
wret = walk_down_log_tree(trans, log, path, &level, wc); if (wret > 0) break; if (wret < 0) {
ret = wret; goto out;
}
wret = walk_up_log_tree(trans, log, path, &level, wc); if (wret > 0) break; if (wret < 0) {
ret = wret; goto out;
}
}
/* was the root node processed? if not, catch it here */ if (path->nodes[orig_level]) {
ret = wc->process_func(log, path->nodes[orig_level], wc,
btrfs_header_generation(path->nodes[orig_level]),
orig_level); if (ret) goto out; if (wc->free)
ret = clean_log_buffer(trans, path->nodes[orig_level]);
}
out:
btrfs_free_path(path); return ret;
}
/* * helper function to update the item for a given subvolumes log root * in the tree of log roots
*/ staticint update_log_root(struct btrfs_trans_handle *trans, struct btrfs_root *log, struct btrfs_root_item *root_item)
{ struct btrfs_fs_info *fs_info = log->fs_info; int ret;
if (log->log_transid == 1) { /* insert root item on the first sync */
ret = btrfs_insert_root(trans, fs_info->log_root_tree,
&log->root_key, root_item);
} else {
ret = btrfs_update_root(trans, fs_info->log_root_tree,
&log->root_key, root_item);
} return ret;
}
staticvoid wait_log_commit(struct btrfs_root *root, int transid)
{
DEFINE_WAIT(wait); int index = transid % 2;
/* * we only allow two pending log transactions at a time, * so we know that if ours is more than 2 older than the * current transaction, we're done
*/ for (;;) {
prepare_to_wait(&root->log_commit_wait[index],
&wait, TASK_UNINTERRUPTIBLE);
if (!(root->log_transid_committed < transid &&
atomic_read(&root->log_commit[index]))) break;
if (!test_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &inode->runtime_flags) &&
!test_bit(BTRFS_INODE_COPY_EVERYTHING, &inode->runtime_flags)) return;
/* * Don't care about allocation failure. This is just for optimization, * if we fail to allocate here, we will try again later if needed.
*/
ctx->scratch_eb = alloc_dummy_extent_buffer(inode->root->fs_info, 0);
}
/* * Invoked in log mutex context, or be sure there is no other task which * can access the list.
*/ staticinlinevoid btrfs_remove_all_log_ctxs(struct btrfs_root *root, int index, int error)
{ struct btrfs_log_ctx *ctx; struct btrfs_log_ctx *safe;
/* * Sends a given tree log down to the disk and updates the super blocks to * record it. When this call is done, you know that any inodes previously * logged are safely on disk only if it returns 0. * * Any other return value means you need to call btrfs_commit_transaction. * Some of the edge cases for fsyncing directories that have had unlinks * or renames done in the past mean that sometimes the only safe * fsync is to commit the whole FS. When btrfs_sync_log returns -EAGAIN, * that has happened.
*/ int btrfs_sync_log(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_log_ctx *ctx)
{ int index1; int index2; int mark; int ret; struct btrfs_fs_info *fs_info = root->fs_info; struct btrfs_root *log = root->log_root; struct btrfs_root *log_root_tree = fs_info->log_root_tree; struct btrfs_root_item new_root_item; int log_transid = 0; struct btrfs_log_ctx root_log_ctx; struct blk_plug plug;
u64 log_root_start;
u64 log_root_level;
/* wait for previous tree log sync to complete */ if (atomic_read(&root->log_commit[(index1 + 1) % 2]))
wait_log_commit(root, log_transid - 1);
while (1) { int batch = atomic_read(&root->log_batch); /* when we're on an ssd, just kick the log commit out */ if (!btrfs_test_opt(fs_info, SSD) &&
test_bit(BTRFS_ROOT_MULTI_LOG_TASKS, &root->state)) {
mutex_unlock(&root->log_mutex);
schedule_timeout_uninterruptible(1);
mutex_lock(&root->log_mutex);
}
wait_for_writer(root); if (batch == atomic_read(&root->log_batch)) break;
}
/* bail out if we need to do a full commit */ if (btrfs_need_log_full_commit(trans)) {
ret = BTRFS_LOG_FORCE_COMMIT;
mutex_unlock(&root->log_mutex); goto out;
}
if (log_transid % 2 == 0)
mark = EXTENT_DIRTY_LOG1; else
mark = EXTENT_DIRTY_LOG2;
/* we start IO on all the marked extents here, but we don't actually * wait for them until later.
*/
blk_start_plug(&plug);
ret = btrfs_write_marked_extents(fs_info, &log->dirty_log_pages, mark); /* * -EAGAIN happens when someone, e.g., a concurrent transaction * commit, writes a dirty extent in this tree-log commit. This * concurrent write will create a hole writing out the extents, * and we cannot proceed on a zoned filesystem, requiring * sequential writing. While we can bail out to a full commit * here, but we can continue hoping the concurrent writing fills * the hole.
*/ if (ret == -EAGAIN && btrfs_is_zoned(fs_info))
ret = 0; if (ret) {
blk_finish_plug(&plug);
btrfs_set_log_full_commit(trans);
mutex_unlock(&root->log_mutex); goto out;
}
/* * We _must_ update under the root->log_mutex in order to make sure we * have a consistent view of the log root we are trying to commit at * this moment. * * We _must_ copy this into a local copy, because we are not holding the * log_root_tree->log_mutex yet. This is important because when we * commit the log_root_tree we must have a consistent view of the * log_root_tree when we update the super block to point at the * log_root_tree bytenr. If we update the log_root_tree here we'll race * with the commit and possibly point at the new block which we may not * have written out.
*/
btrfs_set_root_node(&log->root_item, log->node);
memcpy(&new_root_item, &log->root_item, sizeof(new_root_item));
btrfs_set_root_log_transid(root, root->log_transid + 1);
log->log_transid = root->log_transid;
root->log_start_pid = 0; /* * IO has been started, blocks of the log tree have WRITTEN flag set * in their headers. new modifications of the log will be written to * new positions. so it's safe to allow log writers to go in.
*/
mutex_unlock(&root->log_mutex);
if (btrfs_is_zoned(fs_info)) {
mutex_lock(&fs_info->tree_root->log_mutex); if (!log_root_tree->node) {
ret = btrfs_alloc_log_tree_node(trans, log_root_tree); if (ret) {
mutex_unlock(&fs_info->tree_root->log_mutex);
blk_finish_plug(&plug); goto out;
}
}
mutex_unlock(&fs_info->tree_root->log_mutex);
}
/* * Now we are safe to update the log_root_tree because we're under the * log_mutex, and we're a current writer so we're holding the commit * open until we drop the log_mutex.
*/
ret = update_log_root(trans, log, &new_root_item); if (ret) {
list_del_init(&root_log_ctx.list);
blk_finish_plug(&plug);
btrfs_set_log_full_commit(trans); if (ret != -ENOSPC)
btrfs_err(fs_info, "failed to update log for root %llu ret %d",
btrfs_root_id(root), ret);
btrfs_wait_tree_log_extents(log, mark);
mutex_unlock(&log_root_tree->log_mutex); goto out;
}
if (log_root_tree->log_transid_committed >= root_log_ctx.log_transid) {
blk_finish_plug(&plug);
list_del_init(&root_log_ctx.list);
mutex_unlock(&log_root_tree->log_mutex);
ret = root_log_ctx.log_ret; goto out;
}
if (atomic_read(&log_root_tree->log_commit[index2])) {
blk_finish_plug(&plug);
ret = btrfs_wait_tree_log_extents(log, mark);
wait_log_commit(log_root_tree,
root_log_ctx.log_transid);
mutex_unlock(&log_root_tree->log_mutex); if (!ret)
ret = root_log_ctx.log_ret; goto out;
}
ASSERT(root_log_ctx.log_transid == log_root_tree->log_transid);
atomic_set(&log_root_tree->log_commit[index2], 1);
/* * now that we've moved on to the tree of log tree roots, * check the full commit flag again
*/ if (btrfs_need_log_full_commit(trans)) {
blk_finish_plug(&plug);
btrfs_wait_tree_log_extents(log, mark);
mutex_unlock(&log_root_tree->log_mutex);
ret = BTRFS_LOG_FORCE_COMMIT; goto out_wake_log_root;
}
ret = btrfs_write_marked_extents(fs_info,
&log_root_tree->dirty_log_pages,
EXTENT_DIRTY_LOG1 | EXTENT_DIRTY_LOG2);
blk_finish_plug(&plug); /* * As described above, -EAGAIN indicates a hole in the extents. We * cannot wait for these write outs since the waiting cause a * deadlock. Bail out to the full commit instead.
*/ if (ret == -EAGAIN && btrfs_is_zoned(fs_info)) {
btrfs_set_log_full_commit(trans);
btrfs_wait_tree_log_extents(log, mark);
mutex_unlock(&log_root_tree->log_mutex); goto out_wake_log_root;
} elseif (ret) {
btrfs_set_log_full_commit(trans);
mutex_unlock(&log_root_tree->log_mutex); goto out_wake_log_root;
}
ret = btrfs_wait_tree_log_extents(log, mark); if (!ret)
ret = btrfs_wait_tree_log_extents(log_root_tree,
EXTENT_DIRTY_LOG1 | EXTENT_DIRTY_LOG2); if (ret) {
btrfs_set_log_full_commit(trans);
mutex_unlock(&log_root_tree->log_mutex); goto out_wake_log_root;
}
/* * Here we are guaranteed that nobody is going to write the superblock * for the current transaction before us and that neither we do write * our superblock before the previous transaction finishes its commit * and writes its superblock, because: * * 1) We are holding a handle on the current transaction, so no body * can commit it until we release the handle; * * 2) Before writing our superblock we acquire the tree_log_mutex, so * if the previous transaction is still committing, and hasn't yet * written its superblock, we wait for it to do it, because a * transaction commit acquires the tree_log_mutex when the commit * begins and releases it only after writing its superblock.
*/
mutex_lock(&fs_info->tree_log_mutex);
/* * The previous transaction writeout phase could have failed, and thus * marked the fs in an error state. We must not commit here, as we * could have updated our generation in the super_for_commit and * writing the super here would result in transid mismatches. If there * is an error here just bail.
*/ if (BTRFS_FS_ERROR(fs_info)) {
ret = -EIO;
btrfs_set_log_full_commit(trans);
btrfs_abort_transaction(trans, ret);
mutex_unlock(&fs_info->tree_log_mutex); goto out_wake_log_root;
}
btrfs_set_super_log_root(fs_info->super_for_commit, log_root_start);
btrfs_set_super_log_root_level(fs_info->super_for_commit, log_root_level);
ret = write_all_supers(fs_info, 1);
mutex_unlock(&fs_info->tree_log_mutex); if (ret) {
btrfs_set_log_full_commit(trans);
btrfs_abort_transaction(trans, ret); goto out_wake_log_root;
}
/* * We know there can only be one task here, since we have not yet set * root->log_commit[index1] to 0 and any task attempting to sync the * log must wait for the previous log transaction to commit if it's * still in progress or wait for the current log transaction commit if * someone else already started it. We use <= and not < because the * first log transaction has an ID of 0.
*/
ASSERT(btrfs_get_root_last_log_commit(root) <= log_transid);
btrfs_set_root_last_log_commit(root, log_transid);
/* * The barrier before waitqueue_active (in cond_wake_up) is needed so * all the updates above are seen by the woken threads. It might not be * necessary, but proving that seems to be hard.
*/
cond_wake_up(&log_root_tree->log_commit_wait[index2]);
out:
mutex_lock(&root->log_mutex);
btrfs_remove_all_log_ctxs(root, index1, ret);
root->log_transid_committed++;
atomic_set(&root->log_commit[index1], 0);
mutex_unlock(&root->log_mutex);
/* * The barrier before waitqueue_active (in cond_wake_up) is needed so * all the updates above are seen by the woken threads. It might not be * necessary, but proving that seems to be hard.
*/
cond_wake_up(&root->log_commit_wait[index1]); return ret;
}
if (log->node) {
ret = walk_log_tree(trans, log, &wc); if (ret) { /* * We weren't able to traverse the entire log tree, the * typical scenario is getting an -EIO when reading an * extent buffer of the tree, due to a previous writeback * failure of it.
*/
set_bit(BTRFS_FS_STATE_LOG_CLEANUP_ERROR,
&log->fs_info->fs_state);
/* * Some extent buffers of the log tree may still be dirty * and not yet written back to storage, because we may * have updates to a log tree without syncing a log tree, * such as during rename and link operations. So flush * them out and wait for their writeback to complete, so * that we properly cleanup their state and pages.
*/
btrfs_write_marked_extents(log->fs_info,
&log->dirty_log_pages,
EXTENT_DIRTY_LOG1 | EXTENT_DIRTY_LOG2);
btrfs_wait_tree_log_extents(log,
EXTENT_DIRTY_LOG1 | EXTENT_DIRTY_LOG2);
if (trans)
btrfs_abort_transaction(trans, ret); else
btrfs_handle_fs_error(log->fs_info, ret, NULL);
}
}
/* * free all the extents used by the tree log. This should be called * at commit time of the full transaction
*/ int btrfs_free_log(struct btrfs_trans_handle *trans, struct btrfs_root *root)
{ if (root->log_root) {
free_log_tree(trans, root->log_root);
root->log_root = NULL;
clear_bit(BTRFS_ROOT_HAS_LOG_TREE, &root->state);
} return 0;
}
/* * Do this only if ->logged_trans is still 0 to prevent races with * concurrent logging as we may see the inode not logged when * inode_logged() is called but it gets logged after inode_logged() did * not find it in the log tree and we end up setting ->logged_trans to a * value less than trans->transid after the concurrent logging task has * set it to trans->transid. As a consequence, subsequent rename, unlink * and link operations may end up not logging new names and removing old * names from the log.
*/
spin_lock(&inode->lock); if (inode->logged_trans == 0)
inode->logged_trans = trans->transid - 1; elseif (inode->logged_trans == trans->transid)
ret = true;
spin_unlock(&inode->lock);
return ret;
}
/* * Check if an inode was logged in the current transaction. This correctly deals * with the case where the inode was logged but has a logged_trans of 0, which * happens if the inode is evicted and loaded again, as logged_trans is an in * memory only field (not persisted). * * Returns 1 if the inode was logged before in the transaction, 0 if it was not, * and < 0 on error.
*/ staticint inode_logged(conststruct btrfs_trans_handle *trans, struct btrfs_inode *inode, struct btrfs_path *path_in)
{ struct btrfs_path *path = path_in; struct btrfs_key key; int ret;
/* * Quick lockless call, since once ->logged_trans is set to the current * transaction, we never set it to a lower value anywhere else.
*/ if (data_race(inode->logged_trans) == trans->transid) return 1;
/* * If logged_trans is not 0 and not trans->transid, then we know the * inode was not logged in this transaction, so we can return false * right away. We take the lock to avoid a race caused by load/store * tearing with a concurrent btrfs_log_inode() call or a concurrent task * in this function further below - an update to trans->transid can be * teared into two 32 bits updates for example, in which case we could * see a positive value that is not trans->transid and assume the inode * was not logged when it was.
*/
spin_lock(&inode->lock); if (inode->logged_trans == trans->transid) {
spin_unlock(&inode->lock); return 1;
} elseif (inode->logged_trans > 0) {
spin_unlock(&inode->lock); return 0;
}
spin_unlock(&inode->lock);
/* * If no log tree was created for this root in this transaction, then * the inode can not have been logged in this transaction. In that case * set logged_trans to anything greater than 0 and less than the current * transaction's ID, to avoid the search below in a future call in case * a log tree gets created after this.
*/ if (!test_bit(BTRFS_ROOT_HAS_LOG_TREE, &inode->root->state)) return mark_inode_as_not_logged(trans, inode);
/* * We have a log tree and the inode's logged_trans is 0. We can't tell * for sure if the inode was logged before in this transaction by looking * only at logged_trans. We could be pessimistic and assume it was, but * that can lead to unnecessarily logging an inode during rename and link * operations, and then further updating the log in followup rename and * link operations, specially if it's a directory, which adds latency * visible to applications doing a series of rename or link operations. * * A logged_trans of 0 here can mean several things: * * 1) The inode was never logged since the filesystem was mounted, and may * or may have not been evicted and loaded again; * * 2) The inode was logged in a previous transaction, then evicted and * then loaded again; * * 3) The inode was logged in the current transaction, then evicted and * then loaded again. * * For cases 1) and 2) we don't want to return true, but we need to detect * case 3) and return true. So we do a search in the log root for the inode * item.
*/
key.objectid = btrfs_ino(inode);
key.type = BTRFS_INODE_ITEM_KEY;
key.offset = 0;
if (!path) {
path = btrfs_alloc_path(); if (!path) return -ENOMEM;
}
ret = btrfs_search_slot(NULL, inode->root->log_root, &key, path, 0, 0);
if (path_in)
btrfs_release_path(path); else
btrfs_free_path(path);
/* * Logging an inode always results in logging its inode item. So if we * did not find the item we know the inode was not logged for sure.
*/ if (ret < 0) { return ret;
} elseif (ret > 0) { /* * Set logged_trans to a value greater than 0 and less then the * current transaction to avoid doing the search in future calls.
*/ return mark_inode_as_not_logged(trans, inode);
}
/* * The inode was previously logged and then evicted, set logged_trans to * the current transacion's ID, to avoid future tree searches as long as * the inode is not evicted again.
*/
spin_lock(&inode->lock);
inode->logged_trans = trans->transid;
spin_unlock(&inode->lock);
return 1;
}
/* * Delete a directory entry from the log if it exists. * * Returns < 0 on error * 1 if the entry does not exists * 0 if the entry existed and was successfully deleted
*/ staticint del_logged_dentry(struct btrfs_trans_handle *trans, struct btrfs_root *log, struct btrfs_path *path,
u64 dir_ino, conststruct fscrypt_str *name,
u64 index)
{ struct btrfs_dir_item *di;
/* * We only log dir index items of a directory, so we don't need to look * for dir item keys.
*/
di = btrfs_lookup_dir_index_item(trans, log, path, dir_ino,
index, name, -1); if (IS_ERR(di)) return PTR_ERR(di); elseif (!di) return 1;
/* * We do not need to update the size field of the directory's * inode item because on log replay we update the field to reflect * all existing entries in the directory (see overwrite_item()).
*/ return btrfs_del_item(trans, log, path);
}
/* * If both a file and directory are logged, and unlinks or renames are * mixed in, we have a few interesting corners: * * create file X in dir Y * link file X to X.link in dir Y * fsync file X * unlink file X but leave X.link * fsync dir Y * * After a crash we would expect only X.link to exist. But file X * didn't get fsync'd again so the log has back refs for X and X.link. * * We solve this by removing directory entries and inode backrefs from the * log when a file that was logged in the current transaction is * unlinked. Any later fsync will include the updated log entries, and * we'll be able to reconstruct the proper directory items from backrefs. * * This optimizations allows us to avoid relogging the entire inode * or the entire directory.
*/ void btrfs_del_dir_entries_in_log(struct btrfs_trans_handle *trans, struct btrfs_root *root, conststruct fscrypt_str *name, struct btrfs_inode *dir, u64 index)
{ struct btrfs_path *path; int ret;
ret = inode_logged(trans, dir, NULL); if (ret == 0) return; elseif (ret < 0) {
btrfs_set_log_full_commit(trans); return;
}
path = btrfs_alloc_path(); if (!path) {
btrfs_set_log_full_commit(trans); return;
}
ret = join_running_log_trans(root);
ASSERT(ret == 0, "join_running_log_trans() ret=%d", ret); if (WARN_ON(ret)) goto out;
mutex_lock(&dir->log_mutex);
ret = del_logged_dentry(trans, root->log_root, path, btrfs_ino(dir),
name, index);
mutex_unlock(&dir->log_mutex); if (ret < 0)
btrfs_set_log_full_commit(trans);
btrfs_end_log_trans(root);
out:
btrfs_free_path(path);
}
/* see comments for btrfs_del_dir_entries_in_log */ void btrfs_del_inode_ref_in_log(struct btrfs_trans_handle *trans, struct btrfs_root *root, conststruct fscrypt_str *name, struct btrfs_inode *inode, u64 dirid)
{ struct btrfs_root *log; int ret;
ret = inode_logged(trans, inode, NULL); if (ret == 0) return; elseif (ret < 0) {
btrfs_set_log_full_commit(trans); return;
}
ret = join_running_log_trans(root);
ASSERT(ret == 0, "join_running_log_trans() ret=%d", ret); if (WARN_ON(ret)) return;
log = root->log_root;
mutex_lock(&inode->log_mutex);
ret = btrfs_del_inode_ref(trans, log, name, btrfs_ino(inode), dirid, NULL);
mutex_unlock(&inode->log_mutex); if (ret < 0 && ret != -ENOENT)
btrfs_set_log_full_commit(trans);
btrfs_end_log_trans(root);
}
/* * creates a range item in the log for 'dirid'. first_offset and * last_offset tell us which parts of the key space the log should * be considered authoritative for.
*/ static noinline int insert_dir_log_key(struct btrfs_trans_handle *trans, struct btrfs_root *log, struct btrfs_path *path,
u64 dirid,
u64 first_offset, u64 last_offset)
{ int ret; struct btrfs_key key; struct btrfs_dir_log_item *item;
key.objectid = dirid;
key.type = BTRFS_DIR_LOG_INDEX_KEY;
key.offset = first_offset;
ret = btrfs_insert_empty_item(trans, log, path, &key, sizeof(*item)); /* * -EEXIST is fine and can happen sporadically when we are logging a * directory and have concurrent insertions in the subvolume's tree for * items from other inodes and that result in pushing off some dir items * from one leaf to another in order to accommodate for the new items. * This results in logging the same dir index range key.
*/ if (ret && ret != -EEXIST) return ret;
/* * btrfs_del_dir_entries_in_log() might have been called during * an unlink between the initial insertion of this key and the * current update, or we might be logging a single entry deletion * during a rename, so set the new last_offset to the max value.
*/
last_offset = max(last_offset, curr_end);
}
btrfs_set_dir_log_end(path->nodes[0], item, last_offset);
btrfs_release_path(path); return 0;
}
ret = btrfs_insert_empty_items(trans, log, dst_path, &batch); if (ret) goto out;
dst = dst_path->nodes[0]; /* * Copy all the items in bulk, in a single copy operation. Item data is * organized such that it's placed at the end of a leaf and from right * to left. For example, the data for the second item ends at an offset * that matches the offset where the data for the first item starts, the * data for the third item ends at an offset that matches the offset * where the data of the second items starts, and so on. * Therefore our source and destination start offsets for copy match the * offsets of the last items (highest slots).
*/
dst_offset = btrfs_item_ptr_offset(dst, dst_path->slots[0] + count - 1);
src_offset = btrfs_item_ptr_offset(src, start_slot + count - 1);
copy_extent_buffer(dst, src, dst_offset, src_offset, batch.total_data_size);
btrfs_release_path(dst_path);
/* * If for some unexpected reason the last item's index is not greater * than the last index we logged, warn and force a transaction commit.
*/ if (WARN_ON(last_index <= inode->last_dir_index_offset))
ret = BTRFS_LOG_FORCE_COMMIT; else
inode->last_dir_index_offset = last_index;
if (btrfs_get_first_dir_index_to_log(inode) == 0)
btrfs_set_first_dir_index_to_log(inode, batch.keys[0].offset);
out:
kfree(ins_data);
if (ctx->scratch_eb) {
copy_extent_buffer_full(ctx->scratch_eb, path->nodes[0]);
} else {
ctx->scratch_eb = btrfs_clone_extent_buffer(path->nodes[0]); if (!ctx->scratch_eb) return -ENOMEM;
}
btrfs_release_path(path);
path->nodes[0] = ctx->scratch_eb;
path->slots[0] = slot; /* * Add extra ref to scratch eb so that it is not freed when callers * release the path, so we can reuse it later if needed.
*/
refcount_inc(&ctx->scratch_eb->refs);
/* * We need to clone the leaf, release the read lock on it, and use the * clone before modifying the log tree. See the comment at copy_items() * about why we need to do this.
*/
ret = clone_leaf(path, ctx); if (ret < 0) return ret;
src = path->nodes[0];
for (int i = path->slots[0]; i < nritems; i++) { struct btrfs_dir_item *di; struct btrfs_key key; int ret;
di = btrfs_item_ptr(src, i, struct btrfs_dir_item);
/* * Skip ranges of items that consist only of dir item keys created * in past transactions. However if we find a gap, we must log a * dir index range item for that gap, so that index keys in that * gap are deleted during log replay.
*/ if (btrfs_dir_transid(src, di) < trans->transid) { if (key.offset > *last_old_dentry_offset + 1) {
ret = insert_dir_log_key(trans, log, dst_path,
ino, *last_old_dentry_offset + 1,
key.offset - 1); if (ret < 0) return ret;
}
*last_old_dentry_offset = key.offset; continue;
}
/* If we logged this dir index item before, we can skip it. */ if (key.offset <= inode->last_dir_index_offset) continue;
/* * We must make sure that when we log a directory entry, the * corresponding inode, after log replay, has a matching link * count. For example: * * touch foo * mkdir mydir * sync * ln foo mydir/bar * xfs_io -c "fsync" mydir * <crash> * <mount fs and log replay> * * Would result in a fsync log that when replayed, our file inode * would have a link count of 1, but we get two directory entries * pointing to the same inode. After removing one of the names, * it would not be possible to remove the other name, which * resulted always in stale file handle errors, and would not be * possible to rmdir the parent directory, since its i_size could * never be decremented to the value BTRFS_EMPTY_DIR_SIZE, * resulting in -ENOTEMPTY errors.
*/ if (!ctx->log_new_dentries) { struct btrfs_key di_key;
if (batch_size == 0)
batch_start = i;
batch_size++;
}
if (batch_size > 0) { int ret;
ret = flush_dir_items_batch(trans, inode, src, dst_path,
batch_start, batch_size); if (ret < 0) return ret;
}
return last_found ? 1 : 0;
}
/* * log all the items included in the current transaction for a given * directory. This also creates the range items in the log tree required * to replay anything deleted before the fsync
*/ static noinline int log_dir_items(struct btrfs_trans_handle *trans, struct btrfs_inode *inode, struct btrfs_path *path, struct btrfs_path *dst_path, struct btrfs_log_ctx *ctx,
u64 min_offset, u64 *last_offset_ret)
{ struct btrfs_key min_key; struct btrfs_root *root = inode->root; struct btrfs_root *log = root->log_root; int ret;
u64 last_old_dentry_offset = min_offset - 1;
u64 last_offset = (u64)-1;
u64 ino = btrfs_ino(inode);
ret = btrfs_search_forward(root, &min_key, path, trans->transid);
/* * we didn't find anything from this transaction, see if there * is anything at all
*/ if (ret != 0 || min_key.objectid != ino ||
min_key.type != BTRFS_DIR_INDEX_KEY) {
min_key.objectid = ino;
min_key.type = BTRFS_DIR_INDEX_KEY;
min_key.offset = (u64)-1;
btrfs_release_path(path);
ret = btrfs_search_slot(NULL, root, &min_key, path, 0, 0); if (ret < 0) {
btrfs_release_path(path); return ret;
}
ret = btrfs_previous_item(root, path, ino, BTRFS_DIR_INDEX_KEY);
/* if ret == 0 there are items for this type, * create a range to tell us the last key of this type. * otherwise, there are no items in this directory after * *min_offset, and we create a range to indicate that.
*/ if (ret == 0) { struct btrfs_key tmp;
btrfs_item_key_to_cpu(path->nodes[0], &tmp,
path->slots[0]); if (tmp.type == BTRFS_DIR_INDEX_KEY)
last_old_dentry_offset = tmp.offset;
} elseif (ret > 0) {
ret = 0;
}
goto done;
}
/* go backward to find any previous key */
ret = btrfs_previous_item(root, path, ino, BTRFS_DIR_INDEX_KEY); if (ret == 0) { struct btrfs_key tmp;
btrfs_item_key_to_cpu(path->nodes[0], &tmp, path->slots[0]); /* * The dir index key before the first one we found that needs to * be logged might be in a previous leaf, and there might be a * gap between these keys, meaning that we had deletions that * happened. So the key range item we log (key type * BTRFS_DIR_LOG_INDEX_KEY) must cover a range that starts at the * previous key's offset plus 1, so that those deletes are replayed.
*/ if (tmp.type == BTRFS_DIR_INDEX_KEY)
last_old_dentry_offset = tmp.offset;
} elseif (ret < 0) { goto done;
}
btrfs_release_path(path);
/* * Find the first key from this transaction again or the one we were at * in the loop below in case we had to reschedule. We may be logging the * directory without holding its VFS lock, which happen when logging new * dentries (through log_new_dir_dentries()) or in some cases when we * need to log the parent directory of an inode. This means a dir index * key might be deleted from the inode's root, and therefore we may not * find it anymore. If we can't find it, just move to the next key. We * can not bail out and ignore, because if we do that we will simply * not log dir index keys that come after the one that was just deleted * and we can end up logging a dir index range that ends at (u64)-1 * (@last_offset is initialized to that), resulting in removing dir * entries we should not remove at log replay time.
*/
search:
ret = btrfs_search_slot(NULL, root, &min_key, path, 0, 0); if (ret > 0) {
ret = btrfs_next_item(root, path); if (ret > 0) { /* There are no more keys in the inode's root. */
ret = 0; goto done;
}
} if (ret < 0) goto done;
/* * we have a block from this transaction, log every item in it * from our directory
*/ while (1) {
ret = process_dir_items_leaf(trans, inode, path, dst_path, ctx,
&last_old_dentry_offset); if (ret != 0) { if (ret > 0)
ret = 0; goto done;
}
path->slots[0] = btrfs_header_nritems(path->nodes[0]);
/* * look ahead to the next item and see if it is also * from this directory and from this transaction
*/
ret = btrfs_next_leaf(root, path); if (ret) { if (ret == 1) {
last_offset = (u64)-1;
ret = 0;
} goto done;
}
btrfs_item_key_to_cpu(path->nodes[0], &min_key, path->slots[0]); if (min_key.objectid != ino || min_key.type != BTRFS_DIR_INDEX_KEY) {
last_offset = (u64)-1; goto done;
} if (btrfs_header_generation(path->nodes[0]) != trans->transid) { /* * The next leaf was not changed in the current transaction * and has at least one dir index key. * We check for the next key because there might have been * one or more deletions between the last key we logged and * that next key. So the key range item we log (key type * BTRFS_DIR_LOG_INDEX_KEY) must end at the next key's * offset minus 1, so that those deletes are replayed.
*/
last_offset = min_key.offset - 1; goto done;
} if (need_resched()) {
btrfs_release_path(path);
cond_resched(); goto search;
}
}
done:
btrfs_release_path(path);
btrfs_release_path(dst_path);
if (ret == 0) {
*last_offset_ret = last_offset; /* * In case the leaf was changed in the current transaction but * all its dir items are from a past transaction, the last item * in the leaf is a dir item and there's no gap between that last * dir item and the first one on the next leaf (which did not * change in the current transaction), then we don't need to log * a range, last_old_dentry_offset is == to last_offset.
*/
ASSERT(last_old_dentry_offset <= last_offset); if (last_old_dentry_offset < last_offset)
ret = insert_dir_log_key(trans, log, path, ino,
last_old_dentry_offset + 1,
last_offset);
}
return ret;
}
/* * If the inode was logged before and it was evicted, then its * last_dir_index_offset is 0, so we don't know the value of the last index * key offset. If that's the case, search for it and update the inode. This * is to avoid lookups in the log tree every time we try to insert a dir index * key from a leaf changed in the current transaction, and to allow us to always * do batch insertions of dir index keys.
*/ staticint update_last_dir_index_offset(struct btrfs_inode *inode, struct btrfs_path *path, conststruct btrfs_log_ctx *ctx)
{ const u64 ino = btrfs_ino(inode); struct btrfs_key key; int ret;
ret = btrfs_search_slot(NULL, inode->root->log_root, &key, path, 0, 0); /* * An error happened or we actually have an index key with an offset * value of (u64)-1. Bail out, we're done.
*/ if (ret <= 0) goto out;
ret = 0;
inode->last_dir_index_offset = BTRFS_DIR_START_INDEX - 1;
/* * No dir index items, bail out and leave last_dir_index_offset with * the value right before the first valid index value.
*/ if (path->slots[0] == 0) goto out;
/* * btrfs_search_slot() left us at one slot beyond the slot with the last * index key, or beyond the last key of the directory that is not an * index key. If we have an index key before, set last_dir_index_offset * to its offset value, otherwise leave it with a value right before the * first valid index value, as it means we have an empty directory.
*/
btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0] - 1); if (key.objectid == ino && key.type == BTRFS_DIR_INDEX_KEY)
inode->last_dir_index_offset = key.offset;
out:
btrfs_release_path(path);
return ret;
}
/* * logging directories is very similar to logging inodes, We find all the items * from the current transaction and write them to the log. * * The recovery code scans the directory in the subvolume, and if it finds a * key in the range logged that is not present in the log tree, then it means * that dir entry was unlinked during the transaction. * * In order for that scan to work, we must include one key smaller than * the smallest logged by this transaction and one key larger than the largest * key logged by this transaction.
*/ static noinline int log_directory_changes(struct btrfs_trans_handle *trans, struct btrfs_inode *inode, struct btrfs_path *path, struct btrfs_path *dst_path, struct btrfs_log_ctx *ctx)
{
u64 min_key;
u64 max_key; int ret;
ret = update_last_dir_index_offset(inode, path, ctx); if (ret) return ret;
min_key = BTRFS_DIR_START_INDEX;
max_key = 0;
while (1) {
ret = log_dir_items(trans, inode, path, dst_path,
ctx, min_key, &max_key); if (ret) return ret; if (max_key == (u64)-1) break;
min_key = max_key + 1;
}
return 0;
}
/* * a helper function to drop items from the log before we relog an * inode. max_key_type indicates the highest item type to remove. * This cannot be run for file data extents because it does not * free the extents they point to.
*/ staticint drop_inode_items(struct btrfs_trans_handle *trans, struct btrfs_root *log, struct btrfs_path *path, struct btrfs_inode *inode, int max_key_type)
{ int ret; struct btrfs_key key; struct btrfs_key found_key; int start_slot;
found_key.offset = 0;
found_key.type = 0;
ret = btrfs_bin_search(path->nodes[0], 0, &found_key, &start_slot); if (ret < 0) break;
ret = btrfs_del_items(trans, log, path, start_slot,
path->slots[0] - start_slot + 1); /* * If start slot isn't 0 then we don't need to re-search, we've * found the last guy with the objectid in this tree.
*/ if (ret || start_slot != 0) break;
btrfs_release_path(path);
}
btrfs_release_path(path); if (ret > 0)
ret = 0; return ret;
}
if (log_inode_only) { /* set the generation to zero so the recover code * can tell the difference between an logging * just to say 'this inode exists' and a logging * to say 'update this inode with these values'
*/
btrfs_set_inode_generation(leaf, item, 0);
btrfs_set_inode_size(leaf, item, logged_isize);
} else {
btrfs_set_inode_generation(leaf, item, BTRFS_I(inode)->generation);
btrfs_set_inode_size(leaf, item, inode->i_size);
}
/* * We do not need to set the nbytes field, in fact during a fast fsync * its value may not even be correct, since a fast fsync does not wait * for ordered extent completion, which is where we update nbytes, it * only waits for writeback to complete. During log replay as we find * file extent items and replay them, we adjust the nbytes field of the * inode item in subvolume tree as needed (see overwrite_item()).
*/
btrfs_get_inode_key(inode, &key); /* * If we are doing a fast fsync and the inode was logged before in the * current transaction, then we know the inode was previously logged and * it exists in the log tree. For performance reasons, in this case use * btrfs_search_slot() directly with ins_len set to 0 so that we never * attempt a write lock on the leaf's parent, which adds unnecessary lock * contention in case there are concurrent fsyncs for other inodes of the * same subvolume. Using btrfs_insert_empty_item() when the inode item * already exists can also result in unnecessarily splitting a leaf.
*/ if (!inode_item_dropped && inode->logged_trans == trans->transid) {
ret = btrfs_search_slot(trans, log, &key, path, 0, 1);
ASSERT(ret <= 0); if (ret > 0)
ret = -ENOENT;
} else { /* * This means it is the first fsync in the current transaction, * so the inode item is not in the log and we need to insert it. * We can never get -EEXIST because we are only called for a fast * fsync and in case an inode eviction happens after the inode was * logged before in the current transaction, when we load again * the inode, we set BTRFS_INODE_NEEDS_FULL_SYNC on its runtime * flags and set ->logged_trans to 0.
*/
ret = btrfs_insert_empty_item(trans, log, path, &key, sizeof(*inode_item));
ASSERT(ret != -EEXIST);
} if (ret) return ret;
inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0], struct btrfs_inode_item);
fill_inode_item(trans, path->nodes[0], inode_item, &inode->vfs_inode,
0, 0);
btrfs_release_path(path); return 0;
}
/* * If this inode was not used for reflink operations in the current * transaction with new extents, then do the fast path, no need to * worry about logging checksum items with overlapping ranges.
*/ if (inode->last_reflink_trans < trans->transid) return btrfs_csum_file_blocks(trans, log_root, sums);
/* * Serialize logging for checksums. This is to avoid racing with the * same checksum being logged by another task that is logging another * file which happens to refer to the same extent as well. Such races * can leave checksum items in the log with overlapping ranges.
*/
ret = btrfs_lock_extent(&log_root->log_csum_range, sums->logical, lock_end,
&cached_state); if (ret) return ret; /* * Due to extent cloning, we might have logged a csum item that covers a * subrange of a cloned extent, and later we can end up logging a csum * item for a larger subrange of the same extent or the entire range. * This would leave csum items in the log tree that cover the same range * and break the searches for checksums in the log tree, resulting in * some checksums missing in the fs/subvolume tree. So just delete (or * trim and adjust) any existing csum items in the log for this range.
*/
ret = btrfs_del_csums(trans, log_root, sums->logical, sums->len); if (!ret)
ret = btrfs_csum_file_blocks(trans, log_root, sums);
/* * To keep lockdep happy and avoid deadlocks, clone the source leaf and * use the clone. This is because otherwise we would be changing the log * tree, to insert items from the subvolume tree or insert csum items, * while holding a read lock on a leaf from the subvolume tree, which * creates a nasty lock dependency when COWing log tree nodes/leaves: * * 1) Modifying the log tree triggers an extent buffer allocation while * holding a write lock on a parent extent buffer from the log tree. * Allocating the pages for an extent buffer, or the extent buffer * struct, can trigger inode eviction and finally the inode eviction * will trigger a release/remove of a delayed node, which requires * taking the delayed node's mutex; * * 2) Allocating a metadata extent for a log tree can trigger the async * reclaim thread and make us wait for it to release enough space and * unblock our reservation ticket. The reclaim thread can start * flushing delayed items, and that in turn results in the need to * lock delayed node mutexes and in the need to write lock extent * buffers of a subvolume tree - all this while holding a write lock * on the parent extent buffer in the log tree. * * So one task in scenario 1) running in parallel with another task in * scenario 2) could lead to a deadlock, one wanting to lock a delayed * node mutex while having a read lock on a leaf from the subvolume, * while the other is holding the delayed node's mutex and wants to * write lock the same subvolume leaf for flushing delayed items.
*/
ret = clone_leaf(src_path, ctx); if (ret < 0) return ret;
src = src_path->nodes[0];
ins_data = kmalloc(nr * sizeof(struct btrfs_key) +
nr * sizeof(u32), GFP_NOFS); if (!ins_data) return -ENOMEM;
/* * Don't copy extents from past generations. That would make us * log a lot more metadata for common cases like doing only a * few random writes into a file and then fsync it for the first * time or after the full sync flag is set on the inode. We can * get leaves full of extent items, most of which are from past * generations, so we can skip them - as long as the inode has * not been the target of a reflink operation in this transaction, * as in that case it might have had file extent items with old * generations copied into it. We also must always log prealloc * extents that start at or beyond eof, otherwise we would lose * them on log replay.
*/ if (is_old_extent &&
ins_keys[dst_index].offset < i_size &&
inode->last_reflink_trans < trans->transid) continue;
if (skip_csum) goto add_to_batch;
/* Only regular extents have checksums. */ if (btrfs_file_extent_type(src, extent) != BTRFS_FILE_EXTENT_REG) goto add_to_batch;
/* * If it's an extent created in a past transaction, then its * checksums are already accessible from the committed csum tree, * no need to log them.
*/ if (is_old_extent) goto add_to_batch;
disk_bytenr = btrfs_file_extent_disk_bytenr(src, extent); /* If it's an explicit hole, there are no checksums. */ if (disk_bytenr == 0) goto add_to_batch;
/* See the comment in the previous loop, same logic. */ if (btrfs_file_extent_generation(src, extent) < trans->transid &&
key.offset < i_size &&
inode->last_reflink_trans < trans->transid) continue;
if (ordered_end <= mod_start) continue; if (mod_end <= ordered->file_offset) break;
/* * We are going to copy all the csums on this ordered extent, so * go ahead and adjust mod_start and mod_len in case this ordered * extent has already been logged.
*/ if (ordered->file_offset > mod_start) { if (ordered_end >= mod_end)
mod_len = ordered->file_offset - mod_start; /* * If we have this case * * |--------- logged extent ---------| * |----- ordered extent ----| * * Just don't mess with mod_start and mod_len, we'll * just end up logging more csums than we need and it * will be ok.
*/
} else { if (ordered_end < mod_end) {
mod_len = mod_end - ordered_end;
mod_start = ordered_end;
} else {
mod_len = 0;
}
}
/* * To keep us from looping for the above case of an ordered * extent that falls inside of the logged extent.
*/ if (test_and_set_bit(BTRFS_ORDERED_LOGGED_CSUM, &ordered->flags)) continue;
list_for_each_entry(sums, &ordered->list, list) {
ret = log_csums(trans, inode, log_root, sums); if (ret) return ret;
}
}
/* We're done, found all csums in the ordered extents. */ if (mod_len == 0) return 0;
/* If we're compressed we have to save the entire range of csums. */ if (btrfs_extent_map_is_compressed(em)) {
csum_offset = 0;
csum_len = em->disk_num_bytes;
} else {
csum_offset = mod_start - em->start;
csum_len = mod_len;
}
/* block start is already adjusted for the file extent offset. */
block_start = btrfs_extent_map_block_start(em);
csum_root = btrfs_csum_root(trans->fs_info, block_start);
ret = btrfs_lookup_csums_list(csum_root, block_start + csum_offset,
block_start + csum_offset + csum_len - 1,
&ordered_sums, false); if (ret < 0) return ret;
ret = 0;
while (!list_empty(&ordered_sums)) { struct btrfs_ordered_sum *sums = list_first_entry(&ordered_sums, struct btrfs_ordered_sum,
list); if (!ret)
ret = log_csums(trans, inode, log_root, sums);
list_del(&sums->list);
kfree(sums);
}
ret = log_extent_csums(trans, inode, log, em, ctx); if (ret) return ret;
/* * If this is the first time we are logging the inode in the current * transaction, we can avoid btrfs_drop_extents(), which is expensive * because it does a deletion search, which always acquires write locks * for extent buffers at levels 2, 1 and 0. This not only wastes time * but also adds significant contention in a log tree, since log trees * are small, with a root at level 2 or 3 at most, due to their short * life span.
*/ if (ctx->logged_before) {
drop_args.path = path;
drop_args.start = em->start;
drop_args.end = em->start + em->len;
drop_args.replace_extent = true;
drop_args.extent_item_size = sizeof(fi);
ret = btrfs_drop_extents(trans, log, inode, &drop_args); if (ret) return ret;
}
ret = btrfs_insert_empty_item(trans, log, path, &key, sizeof(fi)); if (ret) return ret;
}
leaf = path->nodes[0];
write_extent_buffer(leaf, &fi,
btrfs_item_ptr_offset(leaf, path->slots[0]), sizeof(fi));
btrfs_release_path(path);
return ret;
}
/* * Log all prealloc extents beyond the inode's i_size to make sure we do not * lose them after doing a full/fast fsync and replaying the log. We scan the * subvolume's root instead of iterating the inode's extent map tree because * otherwise we can log incorrect extent items based on extent map conversion. * That can happen due to the fact that extent maps are merged when they * are not in the extent map tree's list of modified extents.
*/ staticint btrfs_log_prealloc_extents(struct btrfs_trans_handle *trans, struct btrfs_inode *inode, struct btrfs_path *path, struct btrfs_log_ctx *ctx)
{ struct btrfs_root *root = inode->root; struct btrfs_key key; const u64 i_size = i_size_read(&inode->vfs_inode); const u64 ino = btrfs_ino(inode); struct btrfs_path *dst_path = NULL; bool dropped_extents = false;
u64 truncate_offset = i_size; struct extent_buffer *leaf; int slot; int ins_nr = 0; int start_slot = 0; int ret;
if (!(inode->flags & BTRFS_INODE_PREALLOC)) return 0;
/* * We must check if there is a prealloc extent that starts before the * i_size and crosses the i_size boundary. This is to ensure later we * truncate down to the end of that extent and not to the i_size, as * otherwise we end up losing part of the prealloc extent after a log * replay and with an implicit hole if there is another prealloc extent * that starts at an offset beyond i_size.
*/
ret = btrfs_previous_item(root, path, ino, BTRFS_EXTENT_DATA_KEY); if (ret < 0) goto out;
if (ret == 0) { struct btrfs_file_extent_item *ei;
if (extent_end > i_size)
truncate_offset = extent_end;
}
} else {
ret = 0;
}
while (true) {
leaf = path->nodes[0];
slot = path->slots[0];
if (slot >= btrfs_header_nritems(leaf)) { if (ins_nr > 0) {
ret = copy_items(trans, inode, dst_path, path,
start_slot, ins_nr, 1, 0, ctx); if (ret < 0) goto out;
ins_nr = 0;
}
ret = btrfs_next_leaf(root, path); if (ret < 0) goto out; if (ret > 0) {
ret = 0; break;
} continue;
}
btrfs_item_key_to_cpu(leaf, &key, slot); if (key.objectid > ino) break; if (WARN_ON_ONCE(key.objectid < ino) ||
key.type < BTRFS_EXTENT_DATA_KEY ||
key.offset < i_size) {
path->slots[0]++; continue;
} /* * Avoid overlapping items in the log tree. The first time we * get here, get rid of everything from a past fsync. After * that, if the current extent starts before the end of the last * extent we copied, truncate the last one. This can happen if * an ordered extent completion modifies the subvolume tree * while btrfs_next_leaf() has the tree unlocked.
*/ if (!dropped_extents || key.offset < truncate_offset) {
ret = truncate_inode_items(trans, root->log_root, inode,
min(key.offset, truncate_offset),
BTRFS_EXTENT_DATA_KEY); if (ret) goto out;
dropped_extents = true;
}
truncate_offset = btrfs_file_extent_end(path); if (ins_nr == 0)
start_slot = slot;
ins_nr++;
path->slots[0]++; if (!dst_path) {
dst_path = btrfs_alloc_path(); if (!dst_path) {
ret = -ENOMEM; goto out;
}
}
} if (ins_nr > 0)
ret = copy_items(trans, inode, dst_path, path,
start_slot, ins_nr, 1, 0, ctx);
out:
btrfs_release_path(path);
btrfs_free_path(dst_path); return ret;
}
staticint btrfs_log_changed_extents(struct btrfs_trans_handle *trans, struct btrfs_inode *inode, struct btrfs_path *path, struct btrfs_log_ctx *ctx)
{ struct btrfs_ordered_extent *ordered; struct btrfs_ordered_extent *tmp; struct extent_map *em, *n;
LIST_HEAD(extents); struct extent_map_tree *tree = &inode->extent_tree; int ret = 0; int num = 0;
write_lock(&tree->lock);
list_for_each_entry_safe(em, n, &tree->modified_extents, list) {
list_del_init(&em->list); /* * Just an arbitrary number, this can be really CPU intensive * once we start getting a lot of extents, and really once we * have a bunch of extents we just want to commit since it will * be faster.
*/ if (++num > 32768) {
list_del_init(&tree->modified_extents);
ret = -EFBIG; goto process;
}
if (em->generation < trans->transid) continue;
/* We log prealloc extents beyond eof later. */ if ((em->flags & EXTENT_FLAG_PREALLOC) &&
em->start >= i_size_read(&inode->vfs_inode)) continue;
/* Need a ref to keep it from getting evicted from cache */
refcount_inc(&em->refs);
em->flags |= EXTENT_FLAG_LOGGING;
list_add_tail(&em->list, &extents);
num++;
}
list_sort(NULL, &extents, extent_cmp);
process: while (!list_empty(&extents)) {
em = list_first_entry(&extents, struct extent_map, list);
list_del_init(&em->list);
/* * If we had an error we just need to delete everybody from our * private list.
*/ if (ret) {
btrfs_clear_em_logging(inode, em);
btrfs_free_extent_map(em); continue;
}
if (!ret)
ret = btrfs_log_prealloc_extents(trans, inode, path, ctx); if (ret) return ret;
/* * We have logged all extents successfully, now make sure the commit of * the current transaction waits for the ordered extents to complete * before it commits and wipes out the log trees, otherwise we would * lose data if an ordered extents completes after the transaction * commits and a power failure happens after the transaction commit.
*/
list_for_each_entry_safe(ordered, tmp, &ctx->ordered_extents, log_list) {
list_del_init(&ordered->log_list);
set_bit(BTRFS_ORDERED_LOGGED, &ordered->flags);
if (!test_bit(BTRFS_ORDERED_COMPLETE, &ordered->flags)) {
spin_lock_irq(&inode->ordered_tree_lock); if (!test_bit(BTRFS_ORDERED_COMPLETE, &ordered->flags)) {
set_bit(BTRFS_ORDERED_PENDING, &ordered->flags);
atomic_inc(&trans->transaction->pending_ordered);
}
spin_unlock_irq(&inode->ordered_tree_lock);
}
btrfs_put_ordered_extent(ordered);
}
item = btrfs_item_ptr(path->nodes[0], path->slots[0], struct btrfs_inode_item);
*size_ret = btrfs_inode_size(path->nodes[0], item); /* * If the in-memory inode's i_size is smaller then the inode * size stored in the btree, return the inode's i_size, so * that we get a correct inode size after replaying the log * when before a power failure we had a shrinking truncate * followed by addition of a new name (rename / new hard link). * Otherwise return the inode size from the btree, to avoid * data loss when replaying a log due to previously doing a * write that expands the inode's size and logging a new name * immediately after.
*/ if (*size_ret > inode->vfs_inode.i_size)
*size_ret = inode->vfs_inode.i_size;
}
btrfs_release_path(path); return 0;
}
/* * At the moment we always log all xattrs. This is to figure out at log replay * time which xattrs must have their deletion replayed. If a xattr is missing * in the log tree and exists in the fs/subvol tree, we delete it. This is * because if a xattr is deleted, the inode is fsynced and a power failure * happens, causing the log to be replayed the next time the fs is mounted, * we want the xattr to not exist anymore (same behaviour as other filesystems * with a journal, ext3/4, xfs, f2fs, etc).
*/ staticint btrfs_log_all_xattrs(struct btrfs_trans_handle *trans, struct btrfs_inode *inode, struct btrfs_path *path, struct btrfs_path *dst_path, struct btrfs_log_ctx *ctx)
{ struct btrfs_root *root = inode->root; int ret; struct btrfs_key key; const u64 ino = btrfs_ino(inode); int ins_nr = 0; int start_slot = 0; bool found_xattrs = false;
if (test_bit(BTRFS_INODE_NO_XATTRS, &inode->runtime_flags)) return 0;
if (ins_nr == 0)
start_slot = slot;
ins_nr++;
path->slots[0]++;
found_xattrs = true;
cond_resched();
} if (ins_nr > 0) {
ret = copy_items(trans, inode, dst_path, path,
start_slot, ins_nr, 1, 0, ctx); if (ret < 0) return ret;
}
if (!found_xattrs)
set_bit(BTRFS_INODE_NO_XATTRS, &inode->runtime_flags);
return 0;
}
/* * When using the NO_HOLES feature if we punched a hole that causes the * deletion of entire leafs or all the extent items of the first leaf (the one * that contains the inode item and references) we may end up not processing * any extents, because there are no leafs with a generation matching the * current transaction that have extent items for our inode. So we need to find * if any holes exist and then log them. We also need to log holes after any * truncate operation that changes the inode's size.
*/ staticint btrfs_log_holes(struct btrfs_trans_handle *trans, struct btrfs_inode *inode, struct btrfs_path *path)
{ struct btrfs_root *root = inode->root; struct btrfs_fs_info *fs_info = root->fs_info; struct btrfs_key key; const u64 ino = btrfs_ino(inode); const u64 i_size = i_size_read(&inode->vfs_inode);
u64 prev_extent_end = 0; int ret;
if (!btrfs_fs_incompat(fs_info, NO_HOLES) || i_size == 0) return 0;
/* We have a hole, log it. */ if (prev_extent_end < key.offset) { const u64 hole_len = key.offset - prev_extent_end;
/* * Release the path to avoid deadlocks with other code * paths that search the root while holding locks on * leafs from the log root.
*/
btrfs_release_path(path);
ret = btrfs_insert_hole_extent(trans, root->log_root,
ino, prev_extent_end,
hole_len); if (ret < 0) return ret;
/* * Search for the same key again in the root. Since it's * an extent item and we are holding the inode lock, the * key must still exist. If it doesn't just emit warning * and return an error to fall back to a transaction * commit.
*/
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); if (ret < 0) return ret; if (WARN_ON(ret > 0)) return -ENOENT;
leaf = path->nodes[0];
}
/* * When we are logging a new inode X, check if it doesn't have a reference that * matches the reference from some other inode Y created in a past transaction * and that was renamed in the current transaction. If we don't do this, then at * log replay time we can lose inode Y (and all its files if it's a directory): * * mkdir /mnt/x * echo "hello world" > /mnt/x/foobar * sync * mv /mnt/x /mnt/y * mkdir /mnt/x # or touch /mnt/x * xfs_io -c fsync /mnt/x * <power fail> * mount fs, trigger log replay * * After the log replay procedure, we would lose the first directory and all its * files (file foobar). * For the case where inode Y is not a directory we simply end up losing it: * * echo "123" > /mnt/foo * sync * mv /mnt/foo /mnt/bar * echo "abc" > /mnt/foo * xfs_io -c fsync /mnt/foo * <power fail> * * We also need this for cases where a snapshot entry is replaced by some other * entry (file or directory) otherwise we end up with an unreplayable log due to * attempts to delete the snapshot entry (entry of type BTRFS_ROOT_ITEM_KEY) as * if it were a regular entry: * * mkdir /mnt/x * btrfs subvolume snapshot /mnt /mnt/x/snap * btrfs subvolume delete /mnt/x/snap * rmdir /mnt/x * mkdir /mnt/x * fsync /mnt/x or fsync some new file inside it * <power fail> * * The snapshot delete, rmdir of x, mkdir of a new x and the fsync all happen in * the same transaction.
*/ staticint btrfs_check_ref_name_override(struct extent_buffer *eb, constint slot, conststruct btrfs_key *key, struct btrfs_inode *inode,
u64 *other_ino, u64 *other_parent)
{ int ret; struct btrfs_path *search_path; char *name = NULL;
u32 name_len = 0;
u32 item_size = btrfs_item_size(eb, slot);
u32 cur_offset = 0; unsignedlong ptr = btrfs_item_ptr_offset(eb, slot);
/* * Check if we need to log an inode. This is used in contexts where while * logging an inode we need to log another inode (either that it exists or in * full mode). This is used instead of btrfs_inode_in_log() because the later * requires the inode to be in the log and have the log transaction committed, * while here we do not care if the log transaction was already committed - our * caller will commit the log later - and we want to avoid logging an inode * multiple times when multiple tasks have joined the same log transaction.
*/ staticbool need_log_inode(conststruct btrfs_trans_handle *trans, struct btrfs_inode *inode)
{ /* * If a directory was not modified, no dentries added or removed, we can * and should avoid logging it.
*/ if (S_ISDIR(inode->vfs_inode.i_mode) && inode->last_trans < trans->transid) returnfalse;
/* * If this inode does not have new/updated/deleted xattrs since the last * time it was logged and is flagged as logged in the current transaction, * we can skip logging it. As for new/deleted names, those are updated in * the log by link/unlink/rename operations. * In case the inode was logged and then evicted and reloaded, its * logged_trans will be 0, in which case we have to fully log it since * logged_trans is a transient field, not persisted.
*/ if (inode_logged(trans, inode, NULL) == 1 &&
!test_bit(BTRFS_INODE_COPY_EVERYTHING, &inode->runtime_flags)) returnfalse;
/* * Log the inodes of the new dentries of a directory. * See process_dir_items_leaf() for details about why it is needed. * This is a recursive operation - if an existing dentry corresponds to a * directory, that directory's new entries are logged too (same behaviour as * ext3/4, xfs, f2fs, reiserfs, nilfs2). Note that when logging the inodes * the dentries point to we do not acquire their VFS lock, otherwise lockdep * complains about the following circular lock dependency / possible deadlock: * * CPU0 CPU1 * ---- ---- * lock(&type->i_mutex_dir_key#3/2); * lock(sb_internal#2); * lock(&type->i_mutex_dir_key#3/2); * lock(&sb->s_type->i_mutex_key#14); * * Where sb_internal is the lock (a counter that works as a lock) acquired by * sb_start_intwrite() in btrfs_start_transaction(). * Not acquiring the VFS lock of the inodes is still safe because: * * 1) For regular files we log with a mode of LOG_INODE_EXISTS. It's possible * that while logging the inode new references (names) are added or removed * from the inode, leaving the logged inode item with a link count that does * not match the number of logged inode reference items. This is fine because * at log replay time we compute the real number of links and correct the * link count in the inode item (see replay_one_buffer() and * link_to_fixup_dir()); * * 2) For directories we log with a mode of LOG_INODE_ALL. It's possible that * while logging the inode's items new index items (key type * BTRFS_DIR_INDEX_KEY) are added to fs/subvol tree and the logged inode item * has a size that doesn't match the sum of the lengths of all the logged * names - this is ok, not a problem, because at log replay time we set the * directory's i_size to the correct value (see replay_one_name() and * overwrite_item()).
*/ staticint log_new_dir_dentries(struct btrfs_trans_handle *trans, struct btrfs_inode *start_inode, struct btrfs_log_ctx *ctx)
{ struct btrfs_root *root = start_inode->root; struct btrfs_path *path;
LIST_HEAD(dir_list); struct btrfs_dir_list *dir_elem;
u64 ino = btrfs_ino(start_inode); struct btrfs_inode *curr_inode = start_inode; int ret = 0;
/* * If we are logging a new name, as part of a link or rename operation, * don't bother logging new dentries, as we just want to log the names * of an inode and that any new parents exist.
*/ if (ctx->logging_new_name) return 0;
path = btrfs_alloc_path(); if (!path) return -ENOMEM;
/* Pairs with btrfs_add_delayed_iput below. */
ihold(&curr_inode->vfs_inode);
while (true) { struct btrfs_key key; struct btrfs_key found_key;
u64 next_index; bool continue_curr_inode = true; int iter_ret;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); if (WARN_ON_ONCE(ret > 0)) { /* * We have previously found the inode through the commit root * so this should not happen. If it does, just error out and * fallback to a transaction commit.
*/
ret = -ENOENT;
} elseif (ret == 0) { struct btrfs_inode_item *item;
item = btrfs_item_ptr(path->nodes[0], path->slots[0], struct btrfs_inode_item); if (S_ISDIR(btrfs_inode_mode(path->nodes[0], item)))
ret = 1;
}
/* * It's rare to have a lot of conflicting inodes, in practice it is not * common to have more than 1 or 2. We don't want to collect too many, * as we could end up logging too many inodes (even if only in * LOG_INODE_EXISTS mode) and slow down other fsyncs or transaction * commits.
*/ if (ctx->num_conflict_inodes >= MAX_CONFLICT_INODES) return BTRFS_LOG_FORCE_COMMIT;
inode = btrfs_iget_logging(ino, root); /* * If the other inode that had a conflicting dir entry was deleted in * the current transaction then we either: * * 1) Log the parent directory (later after adding it to the list) if * the inode is a directory. This is because it may be a deleted * subvolume/snapshot or it may be a regular directory that had * deleted subvolumes/snapshots (or subdirectories that had them), * and at the moment we can't deal with dropping subvolumes/snapshots * during log replay. So we just log the parent, which will result in * a fallback to a transaction commit if we are dealing with those * cases (last_unlink_trans will match the current transaction); * * 2) Do nothing if it's not a directory. During log replay we simply * unlink the conflicting dentry from the parent directory and then * add the dentry for our inode. Like this we can avoid logging the * parent directory (and maybe fallback to a transaction commit in * case it has a last_unlink_trans == trans->transid, due to moving * some inode from it to some other directory).
*/ if (IS_ERR(inode)) { int ret = PTR_ERR(inode);
if (ret != -ENOENT) return ret;
ret = conflicting_inode_is_dir(root, ino, path); /* Not a directory or we got an error. */ if (ret <= 0) return ret;
/* Conflicting inode is a directory, so we'll log its parent. */
ino_elem = kmalloc(sizeof(*ino_elem), GFP_NOFS); if (!ino_elem) return -ENOMEM;
ino_elem->ino = ino;
ino_elem->parent = parent;
list_add_tail(&ino_elem->list, &ctx->conflict_inodes);
ctx->num_conflict_inodes++;
return 0;
}
/* * If the inode was already logged skip it - otherwise we can hit an * infinite loop. Example: * * From the commit root (previous transaction) we have the following * inodes: * * inode 257 a directory * inode 258 with references "zz" and "zz_link" on inode 257 * inode 259 with reference "a" on inode 257 * * And in the current (uncommitted) transaction we have: * * inode 257 a directory, unchanged * inode 258 with references "a" and "a2" on inode 257 * inode 259 with reference "zz_link" on inode 257 * inode 261 with reference "zz" on inode 257 * * When logging inode 261 the following infinite loop could * happen if we don't skip already logged inodes: * * - we detect inode 258 as a conflicting inode, with inode 261 * on reference "zz", and log it; * * - we detect inode 259 as a conflicting inode, with inode 258 * on reference "a", and log it; * * - we detect inode 258 as a conflicting inode, with inode 259 * on reference "zz_link", and log it - again! After this we * repeat the above steps forever. * * Here we can use need_log_inode() because we only need to log the * inode in LOG_INODE_EXISTS mode and rename operations update the log, * so that the log ends up with the new name and without the old name.
*/ if (!need_log_inode(trans, inode)) {
btrfs_add_delayed_iput(inode); return 0;
}
staticint log_conflicting_inodes(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_log_ctx *ctx)
{ int ret = 0;
/* * Conflicting inodes are logged by the first call to btrfs_log_inode(), * otherwise we could have unbounded recursion of btrfs_log_inode() * calls. This check guarantees we can have only 1 level of recursion.
*/ if (ctx->logging_conflict_inodes) return 0;
ctx->logging_conflict_inodes = true;
/* * New conflicting inodes may be found and added to the list while we * are logging a conflicting inode, so keep iterating while the list is * not empty.
*/ while (!list_empty(&ctx->conflict_inodes)) { struct btrfs_ino_list *curr; struct btrfs_inode *inode;
u64 ino;
u64 parent;
inode = btrfs_iget_logging(ino, root); /* * If the other inode that had a conflicting dir entry was * deleted in the current transaction, we need to log its parent * directory. See the comment at add_conflicting_inode().
*/ if (IS_ERR(inode)) {
ret = PTR_ERR(inode); if (ret != -ENOENT) break;
inode = btrfs_iget_logging(parent, root); if (IS_ERR(inode)) {
ret = PTR_ERR(inode); break;
}
/* * Always log the directory, we cannot make this * conditional on need_log_inode() because the directory * might have been logged in LOG_INODE_EXISTS mode or * the dir index of the conflicting inode is not in a * dir index key range logged for the directory. So we * must make sure the deletion is recorded.
*/
ret = btrfs_log_inode(trans, inode, LOG_INODE_ALL, ctx);
btrfs_add_delayed_iput(inode); if (ret) break; continue;
}
/* * Here we can use need_log_inode() because we only need to log * the inode in LOG_INODE_EXISTS mode and rename operations * update the log, so that the log ends up with the new name and * without the old name. * * We did this check at add_conflicting_inode(), but here we do * it again because if some other task logged the inode after * that, we can avoid doing it again.
*/ if (!need_log_inode(trans, inode)) {
btrfs_add_delayed_iput(inode); continue;
}
/* * We are safe logging the other inode without acquiring its * lock as long as we log with the LOG_INODE_EXISTS mode. We * are safe against concurrent renames of the other inode as * well because during a rename we pin the log and update the * log with the new name before we unpin it.
*/
ret = btrfs_log_inode(trans, inode, LOG_INODE_EXISTS, ctx);
btrfs_add_delayed_iput(inode); if (ret) break;
}
ctx->logging_conflict_inodes = false; if (ret)
free_conflicting_inodes(ctx);
/* * We may process many leaves full of items for our inode, so * avoid monopolizing a cpu for too long by rescheduling while * not holding locks on any tree.
*/
cond_resched();
} if (ins_nr) {
ret = copy_items(trans, inode, dst_path, path, ins_start_slot,
ins_nr, inode_only, logged_isize, ctx); if (ret) return ret;
}
if (inode_only == LOG_INODE_ALL && S_ISREG(inode->vfs_inode.i_mode)) { /* * Release the path because otherwise we might attempt to double * lock the same leaf with btrfs_log_prealloc_extents() below.
*/
btrfs_release_path(path);
ret = btrfs_log_prealloc_extents(trans, inode, dst_path, ctx);
}
/* We are adding dir index items to the log tree. */
lockdep_assert_held(&inode->log_mutex);
/* * We collect delayed items before copying index keys from the subvolume * to the log tree. However just after we collected them, they may have * been flushed (all of them or just some of them), and therefore we * could have copied them from the subvolume tree to the log tree. * So find the first delayed item that was not yet logged (they are * sorted by index number).
*/
list_for_each_entry(curr, delayed_ins_list, log_list) { if (curr->index > inode->last_dir_index_offset) {
first = curr; break;
}
}
/* Empty list or all delayed items were already logged. */ if (!first) return 0;
while (!list_entry_is_head(curr, delayed_del_list, log_list)) {
u64 first_dir_index = curr->index;
u64 last_dir_index; conststruct btrfs_delayed_item *next; int ret;
/* * Find a range of consecutive dir index items to delete. Like * this we log a single dir range item spanning several contiguous * dir items instead of logging one range item per dir index item.
*/
next = list_next_entry(curr, log_list); while (!list_entry_is_head(next, delayed_del_list, log_list)) { if (next->index != curr->index + 1) break;
curr = next;
next = list_next_entry(next, log_list);
}
key.offset = curr->index;
ret = btrfs_search_slot(trans, log, &key, path, -1, 1); if (ret < 0) { return ret;
} elseif (ret == 0) {
ret = batch_delete_dir_index_items(trans, inode, path,
delayed_del_list, curr,
&last); if (ret) return ret;
deleted_items = true;
}
btrfs_release_path(path);
/* * If we deleted items from the leaf, it means we have a range * item logging their range, so no need to add one or update an * existing one. Otherwise we have to log a dir range item.
*/ if (deleted_items) goto next_batch;
last_dir_index = last->index;
ASSERT(last_dir_index >= first_dir_index); /* * If this range starts right after where the previous one ends, * then we want to reuse the previous range item and change its * end offset to the end of this range. This is just to minimize * leaf space usage, by avoiding adding a new range item.
*/ if (last_range_end != 0 && first_dir_index == last_range_end + 1)
first_dir_index = last_range_start;
ret = insert_dir_log_key(trans, log, path, key.objectid,
first_dir_index, last_dir_index); if (ret) return ret;
staticint log_delayed_deletion_items(struct btrfs_trans_handle *trans, struct btrfs_inode *inode, struct btrfs_path *path, conststruct list_head *delayed_del_list, struct btrfs_log_ctx *ctx)
{ /* * We are deleting dir index items from the log tree or adding range * items to it.
*/
lockdep_assert_held(&inode->log_mutex);
if (list_empty(delayed_del_list)) return 0;
if (ctx->logged_before) return log_delayed_deletions_incremental(trans, inode, path,
delayed_del_list, ctx);
/* * Similar logic as for log_new_dir_dentries(), but it iterates over the delayed * items instead of the subvolume tree.
*/ staticint log_new_delayed_dentries(struct btrfs_trans_handle *trans, struct btrfs_inode *inode, conststruct list_head *delayed_ins_list, struct btrfs_log_ctx *ctx)
{ constbool orig_log_new_dentries = ctx->log_new_dentries; struct btrfs_delayed_item *item; int ret = 0;
/* * No need for the log mutex, plus to avoid potential deadlocks or * lockdep annotations due to nesting of delayed inode mutexes and log * mutexes.
*/
lockdep_assert_not_held(&inode->log_mutex);
/* log a single inode in the tree log. * At least one parent directory for this inode must exist in the tree * or be logged already. * * Any items from this inode changed by the current transaction are copied * to the log tree. An extra reference is taken on any extents in this * file, allowing us to avoid a whole pile of corner cases around logging * blocks that have been removed from the tree. * * See LOG_INODE_ALL and related defines for a description of what inode_only * does. * * This handles both files and directories.
*/ staticint btrfs_log_inode(struct btrfs_trans_handle *trans, struct btrfs_inode *inode, int inode_only, struct btrfs_log_ctx *ctx)
{ struct btrfs_path *path; struct btrfs_path *dst_path; struct btrfs_key min_key; struct btrfs_key max_key; struct btrfs_root *log = inode->root->log_root; int ret; bool fast_search = false;
u64 ino = btrfs_ino(inode); struct extent_map_tree *em_tree = &inode->extent_tree;
u64 logged_isize = 0; bool need_log_inode_item = true; bool xattrs_logged = false; bool inode_item_dropped = true; bool full_dir_logging = false;
LIST_HEAD(delayed_ins_list);
LIST_HEAD(delayed_del_list);
path = btrfs_alloc_path(); if (!path) return -ENOMEM;
dst_path = btrfs_alloc_path(); if (!dst_path) {
btrfs_free_path(path); return -ENOMEM;
}
/* today the code can only do partial logging of directories */ if (S_ISDIR(inode->vfs_inode.i_mode) ||
(!test_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
&inode->runtime_flags) &&
inode_only >= LOG_INODE_EXISTS))
max_key.type = BTRFS_XATTR_ITEM_KEY; else
max_key.type = (u8)-1;
max_key.offset = (u64)-1;
if (S_ISDIR(inode->vfs_inode.i_mode) && inode_only == LOG_INODE_ALL)
full_dir_logging = true;
/* * If we are logging a directory while we are logging dentries of the * delayed items of some other inode, then we need to flush the delayed * items of this directory and not log the delayed items directly. This * is to prevent more than one level of recursion into btrfs_log_inode() * by having something like this: * * $ mkdir -p a/b/c/d/e/f/g/h/... * $ xfs_io -c "fsync" a * * Where all directories in the path did not exist before and are * created in the current transaction. * So in such a case we directly log the delayed items of the main * directory ("a") without flushing them first, while for each of its * subdirectories we flush their delayed items before logging them. * This prevents a potential unbounded recursion like this: * * btrfs_log_inode() * log_new_delayed_dentries() * btrfs_log_inode() * log_new_delayed_dentries() * btrfs_log_inode() * log_new_delayed_dentries() * (...) * * We have thresholds for the maximum number of delayed items to have in * memory, and once they are hit, the items are flushed asynchronously. * However the limit is quite high, so lets prevent deep levels of * recursion to happen by limiting the maximum depth to be 1.
*/ if (full_dir_logging && ctx->logging_new_delayed_dentries) {
ret = btrfs_commit_inode_delayed_items(trans, inode); if (ret) goto out;
}
mutex_lock(&inode->log_mutex);
/* * For symlinks, we must always log their content, which is stored in an * inline extent, otherwise we could end up with an empty symlink after * log replay, which is invalid on linux (symlink(2) returns -ENOENT if * one attempts to create an empty symlink). * We don't need to worry about flushing delalloc, because when we create * the inline extent when the symlink is created (we never have delalloc * for symlinks).
*/ if (S_ISLNK(inode->vfs_inode.i_mode))
inode_only = LOG_INODE_ALL;
/* * Before logging the inode item, cache the value returned by * inode_logged(), because after that we have the need to figure out if * the inode was previously logged in this transaction.
*/
ret = inode_logged(trans, inode, path); if (ret < 0) goto out_unlock;
ctx->logged_before = (ret == 1);
ret = 0;
/* * This is for cases where logging a directory could result in losing a * a file after replaying the log. For example, if we move a file from a * directory A to a directory B, then fsync directory A, we have no way * to known the file was moved from A to B, so logging just A would * result in losing the file after a log replay.
*/ if (full_dir_logging && inode->last_unlink_trans >= trans->transid) {
ret = BTRFS_LOG_FORCE_COMMIT; goto out_unlock;
}
/* * a brute force approach to making sure we get the most uptodate * copies of everything.
*/ if (S_ISDIR(inode->vfs_inode.i_mode)) {
clear_bit(BTRFS_INODE_COPY_EVERYTHING, &inode->runtime_flags); if (ctx->logged_before)
ret = drop_inode_items(trans, log, path, inode,
BTRFS_XATTR_ITEM_KEY);
} else { if (inode_only == LOG_INODE_EXISTS && ctx->logged_before) { /* * Make sure the new inode item we write to the log has * the same isize as the current one (if it exists). * This is necessary to prevent data loss after log * replay, and also to prevent doing a wrong expanding * truncate - for e.g. create file, write 4K into offset * 0, fsync, write 4K into offset 4096, add hard link, * fsync some other file (to sync log), power fail - if * we use the inode's current i_size, after log replay * we get a 8Kb file, with the last 4Kb extent as a hole * (zeroes), as if an expanding truncate happened, * instead of getting a file of 4Kb only.
*/
ret = logged_inode_size(log, inode, path, &logged_isize); if (ret) goto out_unlock;
} if (test_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
&inode->runtime_flags)) { if (inode_only == LOG_INODE_EXISTS) {
max_key.type = BTRFS_XATTR_ITEM_KEY; if (ctx->logged_before)
ret = drop_inode_items(trans, log, path,
inode, max_key.type);
} else {
clear_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
&inode->runtime_flags);
clear_bit(BTRFS_INODE_COPY_EVERYTHING,
&inode->runtime_flags); if (ctx->logged_before)
ret = truncate_inode_items(trans, log,
inode, 0, 0);
}
} elseif (test_and_clear_bit(BTRFS_INODE_COPY_EVERYTHING,
&inode->runtime_flags) ||
inode_only == LOG_INODE_EXISTS) { if (inode_only == LOG_INODE_ALL)
fast_search = true;
max_key.type = BTRFS_XATTR_ITEM_KEY; if (ctx->logged_before)
ret = drop_inode_items(trans, log, path, inode,
max_key.type);
} else { if (inode_only == LOG_INODE_ALL)
fast_search = true;
inode_item_dropped = false; goto log_extents;
}
} if (ret) goto out_unlock;
/* * If we are logging a directory in full mode, collect the delayed items * before iterating the subvolume tree, so that we don't miss any new * dir index items in case they get flushed while or right after we are * iterating the subvolume tree.
*/ if (full_dir_logging && !ctx->logging_new_delayed_dentries)
btrfs_log_get_delayed_items(inode, &delayed_ins_list,
&delayed_del_list);
/* * If we are fsyncing a file with 0 hard links, then commit the delayed * inode because the last inode ref (or extref) item may still be in the * subvolume tree and if we log it the file will still exist after a log * replay. So commit the delayed inode to delete that last ref and we * skip logging it.
*/ if (inode->vfs_inode.i_nlink == 0) {
ret = btrfs_commit_inode_delayed_inode(inode); if (ret) goto out_unlock;
}
ret = copy_inode_items_to_log(trans, inode, &min_key, &max_key,
path, dst_path, logged_isize,
inode_only, ctx,
&need_log_inode_item); if (ret) goto out_unlock;
btrfs_release_path(path);
btrfs_release_path(dst_path);
ret = btrfs_log_all_xattrs(trans, inode, path, dst_path, ctx); if (ret) goto out_unlock;
xattrs_logged = true; if (max_key.type >= BTRFS_EXTENT_DATA_KEY && !fast_search) {
btrfs_release_path(path);
btrfs_release_path(dst_path);
ret = btrfs_log_holes(trans, inode, path); if (ret) goto out_unlock;
}
log_extents:
btrfs_release_path(path);
btrfs_release_path(dst_path); if (need_log_inode_item) {
ret = log_inode_item(trans, log, dst_path, inode, inode_item_dropped); if (ret) goto out_unlock; /* * If we are doing a fast fsync and the inode was logged before * in this transaction, we don't need to log the xattrs because * they were logged before. If xattrs were added, changed or * deleted since the last time we logged the inode, then we have * already logged them because the inode had the runtime flag * BTRFS_INODE_COPY_EVERYTHING set.
*/ if (!xattrs_logged && inode->logged_trans < trans->transid) {
ret = btrfs_log_all_xattrs(trans, inode, path, dst_path, ctx); if (ret) goto out_unlock;
btrfs_release_path(path);
}
} if (fast_search) {
ret = btrfs_log_changed_extents(trans, inode, dst_path, ctx); if (ret) goto out_unlock;
} elseif (inode_only == LOG_INODE_ALL) { struct extent_map *em, *n;
write_lock(&em_tree->lock);
list_for_each_entry_safe(em, n, &em_tree->modified_extents, list)
list_del_init(&em->list);
write_unlock(&em_tree->lock);
}
if (full_dir_logging) {
ret = log_directory_changes(trans, inode, path, dst_path, ctx); if (ret) goto out_unlock;
ret = log_delayed_insertion_items(trans, inode, path,
&delayed_ins_list, ctx); if (ret) goto out_unlock;
ret = log_delayed_deletion_items(trans, inode, path,
&delayed_del_list, ctx); if (ret) goto out_unlock;
}
spin_lock(&inode->lock);
inode->logged_trans = trans->transid; /* * Don't update last_log_commit if we logged that an inode exists. * We do this for three reasons: * * 1) We might have had buffered writes to this inode that were * flushed and had their ordered extents completed in this * transaction, but we did not previously log the inode with * LOG_INODE_ALL. Later the inode was evicted and after that * it was loaded again and this LOG_INODE_EXISTS log operation * happened. We must make sure that if an explicit fsync against * the inode is performed later, it logs the new extents, an * updated inode item, etc, and syncs the log. The same logic * applies to direct IO writes instead of buffered writes. * * 2) When we log the inode with LOG_INODE_EXISTS, its inode item * is logged with an i_size of 0 or whatever value was logged * before. If later the i_size of the inode is increased by a * truncate operation, the log is synced through an fsync of * some other inode and then finally an explicit fsync against * this inode is made, we must make sure this fsync logs the * inode with the new i_size, the hole between old i_size and * the new i_size, and syncs the log. * * 3) If we are logging that an ancestor inode exists as part of * logging a new name from a link or rename operation, don't update * its last_log_commit - otherwise if an explicit fsync is made * against an ancestor, the fsync considers the inode in the log * and doesn't sync the log, resulting in the ancestor missing after * a power failure unless the log was synced as part of an fsync * against any other unrelated inode.
*/ if (!ctx->logging_new_name && inode_only != LOG_INODE_EXISTS)
inode->last_log_commit = inode->last_sub_trans;
spin_unlock(&inode->lock);
/* * Reset the last_reflink_trans so that the next fsync does not need to * go through the slower path when logging extents and their checksums.
*/ if (inode_only == LOG_INODE_ALL)
inode->last_reflink_trans = 0;
dir_inode = btrfs_iget_logging(inode_key.objectid, root); /* * If the parent inode was deleted, return an error to * fallback to a transaction commit. This is to prevent * getting an inode that was moved from one parent A to * a parent B, got its former parent A deleted and then * it got fsync'ed, from existing at both parents after * a log replay (and the old parent still existing). * Example: * * mkdir /mnt/A * mkdir /mnt/B * touch /mnt/B/bar * sync * mv /mnt/B/bar /mnt/A/bar * mv -T /mnt/A /mnt/B * fsync /mnt/B/bar * <power fail> * * If we ignore the old parent B which got deleted, * after a log replay we would have file bar linked * at both parents and the old parent B would still * exist.
*/ if (IS_ERR(dir_inode)) {
ret = PTR_ERR(dir_inode); goto out;
}
if (!need_log_inode(trans, dir_inode)) {
btrfs_add_delayed_iput(dir_inode); continue;
}
ctx->log_new_dentries = false;
ret = btrfs_log_inode(trans, dir_inode, LOG_INODE_ALL, ctx); if (!ret && ctx->log_new_dentries)
ret = log_new_dir_dentries(trans, dir_inode, ctx);
btrfs_add_delayed_iput(dir_inode); if (ret) goto out;
}
path->slots[0]++;
}
ret = 0;
out:
btrfs_free_path(path); return ret;
}
/* * For a single hard link case, go through a fast path that does not * need to iterate the fs/subvolume tree.
*/ if (inode->vfs_inode.i_nlink < 2) return log_new_ancestors_fast(trans, inode, parent, ctx);
path = btrfs_alloc_path(); if (!path) return -ENOMEM;
search_key.objectid = ino;
search_key.type = BTRFS_INODE_REF_KEY;
search_key.offset = 0;
again:
ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0); if (ret < 0) goto out; if (ret == 0)
path->slots[0]++;
while (true) { struct extent_buffer *leaf = path->nodes[0]; int slot = path->slots[0]; struct btrfs_key found_key;
if (slot >= btrfs_header_nritems(leaf)) {
ret = btrfs_next_leaf(root, path); if (ret < 0) goto out; elseif (ret > 0) break; continue;
}
/* * Don't deal with extended references because they are rare * cases and too complex to deal with (we would need to keep * track of which subitem we are processing for each item in * this loop, etc). So just return some error to fallback to * a transaction commit.
*/ if (found_key.type == BTRFS_INODE_EXTREF_KEY) {
ret = -EMLINK; goto out;
}
/* * Logging ancestors needs to do more searches on the fs/subvol * tree, so it releases the path as needed to avoid deadlocks. * Keep track of the last inode ref key and resume from that key * after logging all new ancestors for the current hard link.
*/
memcpy(&search_key, &found_key, sizeof(search_key));
ret = log_new_ancestors(trans, root, path, ctx); if (ret) goto out;
btrfs_release_path(path); goto again;
}
ret = 0;
out:
btrfs_free_path(path); return ret;
}
/* * helper function around btrfs_log_inode to make sure newly created * parent directories also end up in the log. A minimal inode and backref * only logging is done of any parent directories that are older than * the last committed transaction
*/ staticint btrfs_log_inode_parent(struct btrfs_trans_handle *trans, struct btrfs_inode *inode, struct dentry *parent, int inode_only, struct btrfs_log_ctx *ctx)
{ struct btrfs_root *root = inode->root; struct btrfs_fs_info *fs_info = root->fs_info; int ret = 0; bool log_dentries;
if (btrfs_test_opt(fs_info, NOTREELOG)) return BTRFS_LOG_FORCE_COMMIT;
if (btrfs_root_refs(&root->root_item) == 0) return BTRFS_LOG_FORCE_COMMIT;
/* * If we're logging an inode from a subvolume created in the current * transaction we must force a commit since the root is not persisted.
*/ if (btrfs_root_generation(&root->root_item) == trans->transid) return BTRFS_LOG_FORCE_COMMIT;
/* Skip already logged inodes and without new extents. */ if (btrfs_inode_in_log(inode, trans->transid) &&
list_empty(&ctx->ordered_extents)) return BTRFS_NO_LOG_SYNC;
ret = start_log_trans(trans, root, ctx); if (ret) return ret;
ret = btrfs_log_inode(trans, inode, inode_only, ctx); if (ret) goto end_trans;
/* * for regular files, if its inode is already on disk, we don't * have to worry about the parents at all. This is because * we can use the last_unlink_trans field to record renames * and other fun in this file.
*/ if (S_ISREG(inode->vfs_inode.i_mode) &&
inode->generation < trans->transid &&
inode->last_unlink_trans < trans->transid) {
ret = 0; goto end_trans;
}
/* * Track if we need to log dentries because ctx->log_new_dentries can * be modified in the call chains below.
*/
log_dentries = ctx->log_new_dentries;
/* * On unlink we must make sure all our current and old parent directory * inodes are fully logged. This is to prevent leaving dangling * directory index entries in directories that were our parents but are * not anymore. Not doing this results in old parent directory being * impossible to delete after log replay (rmdir will always fail with * error -ENOTEMPTY). * * Example 1: * * mkdir testdir * touch testdir/foo * ln testdir/foo testdir/bar * sync * unlink testdir/bar * xfs_io -c fsync testdir/foo * <power failure> * mount fs, triggers log replay * * If we don't log the parent directory (testdir), after log replay the * directory still has an entry pointing to the file inode using the bar * name, but a matching BTRFS_INODE_[REF|EXTREF]_KEY does not exist and * the file inode has a link count of 1. * * Example 2: * * mkdir testdir * touch foo * ln foo testdir/foo2 * ln foo testdir/foo3 * sync * unlink testdir/foo3 * xfs_io -c fsync foo * <power failure> * mount fs, triggers log replay * * Similar as the first example, after log replay the parent directory * testdir still has an entry pointing to the inode file with name foo3 * but the file inode does not have a matching BTRFS_INODE_REF_KEY item * and has a link count of 2.
*/ if (inode->last_unlink_trans >= trans->transid) {
ret = btrfs_log_all_parents(trans, inode, ctx); if (ret) goto end_trans;
}
ret = log_all_new_ancestors(trans, inode, parent, ctx); if (ret) goto end_trans;
if (log_dentries)
ret = log_new_dir_dentries(trans, inode, ctx);
end_trans: if (ret < 0) {
btrfs_set_log_full_commit(trans);
ret = BTRFS_LOG_FORCE_COMMIT;
}
if (ret)
btrfs_remove_log_ctx(root, ctx);
btrfs_end_log_trans(root);
return ret;
}
/* * it is not safe to log dentry if the chunk root has added new * chunks. This returns 0 if the dentry was logged, and 1 otherwise. * If this returns 1, you must commit the transaction to safely get your * data on disk.
*/ int btrfs_log_dentry_safe(struct btrfs_trans_handle *trans, struct dentry *dentry, struct btrfs_log_ctx *ctx)
{ struct dentry *parent = dget_parent(dentry); int ret;
ret = btrfs_log_inode_parent(trans, BTRFS_I(d_inode(dentry)), parent,
LOG_INODE_ALL, ctx);
dput(parent);
return ret;
}
/* * should be called during mount to recover any replay any log trees * from the FS
*/ int btrfs_recover_log_trees(struct btrfs_root *log_root_tree)
{ int ret; struct btrfs_path *path; struct btrfs_trans_handle *trans; struct btrfs_key key; struct btrfs_fs_info *fs_info = log_root_tree->fs_info; struct walk_control wc = {
.process_func = process_one_buffer,
.stage = LOG_WALK_PIN_ONLY,
};
path = btrfs_alloc_path(); if (!path) return -ENOMEM;
while (1) { struct btrfs_root *log; struct btrfs_key found_key;
ret = btrfs_search_slot(NULL, log_root_tree, &key, path, 0, 0);
if (ret < 0) {
btrfs_abort_transaction(trans, ret); goto error;
} if (ret > 0) { if (path->slots[0] == 0) break;
path->slots[0]--;
}
btrfs_item_key_to_cpu(path->nodes[0], &found_key,
path->slots[0]);
btrfs_release_path(path); if (found_key.objectid != BTRFS_TREE_LOG_OBJECTID) break;
log = btrfs_read_tree_root(log_root_tree, &found_key); if (IS_ERR(log)) {
ret = PTR_ERR(log);
btrfs_abort_transaction(trans, ret); goto error;
}
wc.replay_dest = btrfs_get_fs_root(fs_info, found_key.offset, true); if (IS_ERR(wc.replay_dest)) {
ret = PTR_ERR(wc.replay_dest);
wc.replay_dest = NULL; if (ret != -ENOENT) {
btrfs_put_root(log);
btrfs_abort_transaction(trans, ret); goto error;
}
/* * We didn't find the subvol, likely because it was * deleted. This is ok, simply skip this log and go to * the next one. * * We need to exclude the root because we can't have * other log replays overwriting this log as we'll read * it back in a few more times. This will keep our * block from being modified, and we'll just bail for * each subsequent pass.
*/
ret = btrfs_pin_extent_for_log_replay(trans, log->node); if (ret) {
btrfs_put_root(log);
btrfs_abort_transaction(trans, ret); goto error;
} goto next;
}
wc.replay_dest->log_root = log;
ret = btrfs_record_root_in_trans(trans, wc.replay_dest); if (ret) {
btrfs_abort_transaction(trans, ret); goto next;
}
ret = walk_log_tree(trans, log, &wc); if (ret) {
btrfs_abort_transaction(trans, ret); goto next;
}
if (wc.stage == LOG_WALK_REPLAY_ALL) { struct btrfs_root *root = wc.replay_dest;
ret = fixup_inode_link_counts(trans, wc.replay_dest, path); if (ret) {
btrfs_abort_transaction(trans, ret); goto next;
} /* * We have just replayed everything, and the highest * objectid of fs roots probably has changed in case * some inode_item's got replayed. * * root->objectid_mutex is not acquired as log replay * could only happen during mount.
*/
ret = btrfs_init_root_free_objectid(root); if (ret) {
btrfs_abort_transaction(trans, ret); goto next;
}
}
next: if (wc.replay_dest) {
wc.replay_dest->log_root = NULL;
btrfs_put_root(wc.replay_dest);
}
btrfs_put_root(log);
if (ret) goto error; if (found_key.offset == 0) break;
key.offset = found_key.offset - 1;
}
btrfs_release_path(path);
/* step one is to pin it all, step two is to replay just inodes */ if (wc.pin) {
wc.pin = 0;
wc.process_func = replay_one_buffer;
wc.stage = LOG_WALK_REPLAY_INODES; goto again;
} /* step three is to replay everything */ if (wc.stage < LOG_WALK_REPLAY_ALL) {
wc.stage++; goto again;
}
btrfs_free_path(path);
/* step 4: commit the transaction, which also unpins the blocks */
ret = btrfs_commit_transaction(trans); if (ret) return ret;
/* * there are some corner cases where we want to force a full * commit instead of allowing a directory to be logged. * * They revolve around files there were unlinked from the directory, and * this function updates the parent directory so that a full commit is * properly done if it is fsync'd later after the unlinks are done. * * Must be called before the unlink operations (updates to the subvolume tree, * inodes, etc) are done.
*/ void btrfs_record_unlink_dir(struct btrfs_trans_handle *trans, struct btrfs_inode *dir, struct btrfs_inode *inode, bool for_rename)
{ /* * when we're logging a file, if it hasn't been renamed * or unlinked, and its inode is fully committed on disk, * we don't have to worry about walking up the directory chain * to log its parents. * * So, we use the last_unlink_trans field to put this transid * into the file. When the file is logged we check it and * don't log the parents if the file is fully on disk.
*/
mutex_lock(&inode->log_mutex);
inode->last_unlink_trans = trans->transid;
mutex_unlock(&inode->log_mutex);
if (!for_rename) return;
/* * If this directory was already logged, any new names will be logged * with btrfs_log_new_name() and old names will be deleted from the log * tree with btrfs_del_dir_entries_in_log() or with * btrfs_del_inode_ref_in_log().
*/ if (inode_logged(trans, dir, NULL) == 1) return;
/* * If the inode we're about to unlink was logged before, the log will be * properly updated with the new name with btrfs_log_new_name() and the * old name removed with btrfs_del_dir_entries_in_log() or with * btrfs_del_inode_ref_in_log().
*/ if (inode_logged(trans, inode, NULL) == 1) return;
/* * when renaming files across directories, if the directory * there we're unlinking from gets fsync'd later on, there's * no way to find the destination directory later and fsync it * properly. So, we have to be conservative and force commits * so the new name gets discovered.
*/
mutex_lock(&dir->log_mutex);
dir->last_unlink_trans = trans->transid;
mutex_unlock(&dir->log_mutex);
}
/* * Make sure that if someone attempts to fsync the parent directory of a deleted * snapshot, it ends up triggering a transaction commit. This is to guarantee * that after replaying the log tree of the parent directory's root we will not * see the snapshot anymore and at log replay time we will not see any log tree * corresponding to the deleted snapshot's root, which could lead to replaying * it after replaying the log tree of the parent directory (which would replay * the snapshot delete operation). * * Must be called before the actual snapshot destroy operation (updates to the * parent root and tree of tree roots trees, etc) are done.
*/ void btrfs_record_snapshot_destroy(struct btrfs_trans_handle *trans, struct btrfs_inode *dir)
{
mutex_lock(&dir->log_mutex);
dir->last_unlink_trans = trans->transid;
mutex_unlock(&dir->log_mutex);
}
/* * Call this when creating a subvolume in a directory. * Because we don't commit a transaction when creating a subvolume, we can't * allow the directory pointing to the subvolume to be logged with an entry that * points to an unpersisted root if we are still in the transaction used to * create the subvolume, so make any attempt to log the directory to result in a * full log sync. * Also we don't need to worry with renames, since btrfs_rename() marks the log * for full commit when renaming a subvolume. * * Must be called before creating the subvolume entry in its parent directory.
*/ void btrfs_record_new_subvolume(conststruct btrfs_trans_handle *trans, struct btrfs_inode *dir)
{
mutex_lock(&dir->log_mutex);
dir->last_unlink_trans = trans->transid;
mutex_unlock(&dir->log_mutex);
}
/* * Update the log after adding a new name for an inode. * * @trans: Transaction handle. * @old_dentry: The dentry associated with the old name and the old * parent directory. * @old_dir: The inode of the previous parent directory for the case * of a rename. For a link operation, it must be NULL. * @old_dir_index: The index number associated with the old name, meaningful * only for rename operations (when @old_dir is not NULL). * Ignored for link operations. * @parent: The dentry associated with the directory under which the * new name is located. * * Call this after adding a new name for an inode, as a result of a link or * rename operation, and it will properly update the log to reflect the new name.
*/ void btrfs_log_new_name(struct btrfs_trans_handle *trans, struct dentry *old_dentry, struct btrfs_inode *old_dir,
u64 old_dir_index, struct dentry *parent)
{ struct btrfs_inode *inode = BTRFS_I(d_inode(old_dentry)); struct btrfs_root *root = inode->root; struct btrfs_log_ctx ctx; bool log_pinned = false; int ret;
/* * this will force the logging code to walk the dentry chain * up for the file
*/ if (!S_ISDIR(inode->vfs_inode.i_mode))
inode->last_unlink_trans = trans->transid;
/* * if this inode hasn't been logged and directory we're renaming it * from hasn't been logged, we don't need to log it
*/
ret = inode_logged(trans, inode, NULL); if (ret < 0) { goto out;
} elseif (ret == 0) { if (!old_dir) return; /* * If the inode was not logged and we are doing a rename (old_dir is not * NULL), check if old_dir was logged - if it was not we can return and * do nothing.
*/
ret = inode_logged(trans, old_dir, NULL); if (ret < 0) goto out; elseif (ret == 0) return;
}
ret = 0;
/* * Now that we know we need to update the log, allocate the scratch eb * for the context before joining a log transaction below, as this can * take time and therefore we could delay log commits from other tasks.
*/
btrfs_init_log_ctx_scratch_eb(&ctx);
/* * If we are doing a rename (old_dir is not NULL) from a directory that * was previously logged, make sure that on log replay we get the old * dir entry deleted. This is needed because we will also log the new * name of the renamed inode, so we need to make sure that after log * replay we don't end up with both the new and old dir entries existing.
*/ if (old_dir && old_dir->logged_trans == trans->transid) { struct btrfs_root *log = old_dir->root->log_root; struct btrfs_path *path; struct fscrypt_name fname;
ASSERT(old_dir_index >= BTRFS_DIR_START_INDEX);
ret = fscrypt_setup_filename(&old_dir->vfs_inode,
&old_dentry->d_name, 0, &fname); if (ret) goto out;
path = btrfs_alloc_path(); if (!path) {
ret = -ENOMEM;
fscrypt_free_filename(&fname); goto out;
}
/* * We have two inodes to update in the log, the old directory and * the inode that got renamed, so we must pin the log to prevent * anyone from syncing the log until we have updated both inodes * in the log.
*/
ret = join_running_log_trans(root); /* * At least one of the inodes was logged before, so this should * not fail, but if it does, it's not serious, just bail out and * mark the log for a full commit.
*/ if (WARN_ON_ONCE(ret < 0)) {
btrfs_free_path(path);
fscrypt_free_filename(&fname); goto out;
}
log_pinned = true;
/* * Other concurrent task might be logging the old directory, * as it can be triggered when logging other inode that had or * still has a dentry in the old directory. We lock the old * directory's log_mutex to ensure the deletion of the old * name is persisted, because during directory logging we * delete all BTRFS_DIR_LOG_INDEX_KEY keys and the deletion of * the old name's dir index item is in the delayed items, so * it could be missed by an in progress directory logging.
*/
mutex_lock(&old_dir->log_mutex);
ret = del_logged_dentry(trans, log, path, btrfs_ino(old_dir),
&fname.disk_name, old_dir_index); if (ret > 0) { /* * The dentry does not exist in the log, so record its * deletion.
*/
btrfs_release_path(path);
ret = insert_dir_log_key(trans, log, path,
btrfs_ino(old_dir),
old_dir_index, old_dir_index);
}
mutex_unlock(&old_dir->log_mutex);
btrfs_free_path(path);
fscrypt_free_filename(&fname); if (ret < 0) goto out;
}
/* * We don't care about the return value. If we fail to log the new name * then we know the next attempt to sync the log will fallback to a full * transaction commit (due to a call to btrfs_set_log_full_commit()), so * we don't need to worry about getting a log committed that has an * inconsistent state after a rename operation.
*/
btrfs_log_inode_parent(trans, inode, parent, LOG_INODE_EXISTS, &ctx);
ASSERT(list_empty(&ctx.conflict_inodes));
out: /* * If an error happened mark the log for a full commit because it's not * consistent and up to date or we couldn't find out if one of the * inodes was logged before in this transaction. Do it before unpinning * the log, to avoid any races with someone else trying to commit it.
*/ if (ret < 0)
btrfs_set_log_full_commit(trans); if (log_pinned)
btrfs_end_log_trans(root);
free_extent_buffer(ctx.scratch_eb);
}
Messung V0.5 in Prozent
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Die Informationen auf dieser Webseite wurden
nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit,
noch Qualität der bereit gestellten Informationen zugesichert.
Bemerkung:
Die farbliche Syntaxdarstellung und die Messung sind noch experimentell.
