/* * Look up the first record less than or equal to [bno, len] in the btree * given by cur.
*/ int
xfs_refcount_lookup_le( struct xfs_btree_cur *cur, enum xfs_refc_domain domain,
xfs_agblock_t bno, int *stat)
{
trace_xfs_refcount_lookup(cur,
xfs_refcount_encode_startblock(bno, domain),
XFS_LOOKUP_LE);
cur->bc_rec.rc.rc_startblock = bno;
cur->bc_rec.rc.rc_blockcount = 0;
cur->bc_rec.rc.rc_domain = domain; return xfs_btree_lookup(cur, XFS_LOOKUP_LE, stat);
}
/* * Look up the first record greater than or equal to [bno, len] in the btree * given by cur.
*/ int
xfs_refcount_lookup_ge( struct xfs_btree_cur *cur, enum xfs_refc_domain domain,
xfs_agblock_t bno, int *stat)
{
trace_xfs_refcount_lookup(cur,
xfs_refcount_encode_startblock(bno, domain),
XFS_LOOKUP_GE);
cur->bc_rec.rc.rc_startblock = bno;
cur->bc_rec.rc.rc_blockcount = 0;
cur->bc_rec.rc.rc_domain = domain; return xfs_btree_lookup(cur, XFS_LOOKUP_GE, stat);
}
/* * Look up the first record equal to [bno, len] in the btree * given by cur.
*/ int
xfs_refcount_lookup_eq( struct xfs_btree_cur *cur, enum xfs_refc_domain domain,
xfs_agblock_t bno, int *stat)
{
trace_xfs_refcount_lookup(cur,
xfs_refcount_encode_startblock(bno, domain),
XFS_LOOKUP_LE);
cur->bc_rec.rc.rc_startblock = bno;
cur->bc_rec.rc.rc_blockcount = 0;
cur->bc_rec.rc.rc_domain = domain; return xfs_btree_lookup(cur, XFS_LOOKUP_EQ, stat);
}
/* Convert on-disk record to in-core format. */ void
xfs_refcount_btrec_to_irec( constunion xfs_btree_rec *rec, struct xfs_refcount_irec *irec)
{
uint32_t start;
if (xfs_btree_is_rtrefcount(cur->bc_ops)) {
xfs_warn(mp, "RT Refcount BTree record corruption in rtgroup %u detected at %pS!",
cur->bc_group->xg_gno, fa);
} else {
xfs_warn(mp, "Refcount BTree record corruption in AG %d detected at %pS!",
cur->bc_group->xg_gno, fa);
}
xfs_warn(mp, "Start block 0x%x, block count 0x%x, references 0x%x",
irec->rc_startblock, irec->rc_blockcount, irec->rc_refcount);
xfs_btree_mark_sick(cur); return -EFSCORRUPTED;
}
/* * Get the data from the pointed-to record.
*/ int
xfs_refcount_get_rec( struct xfs_btree_cur *cur, struct xfs_refcount_irec *irec, int *stat)
{ union xfs_btree_rec *rec;
xfs_failaddr_t fa; int error;
xfs_refcount_btrec_to_irec(rec, irec);
fa = xfs_refcount_check_btrec(cur, irec); if (fa) return xfs_refcount_complain_bad_rec(cur, fa, irec);
trace_xfs_refcount_get(cur, irec); return 0;
}
/* * Update the record referred to by cur to the value given * by [bno, len, refcount]. * This either works (return 0) or gets an EFSCORRUPTED error.
*/ STATICint
xfs_refcount_update( struct xfs_btree_cur *cur, struct xfs_refcount_irec *irec)
{ union xfs_btree_rec rec;
uint32_t start; int error;
/* * Insert the record referred to by cur to the value given * by [bno, len, refcount]. * This either works (return 0) or gets an EFSCORRUPTED error.
*/ int
xfs_refcount_insert( struct xfs_btree_cur *cur, struct xfs_refcount_irec *irec, int *i)
{ int error;
out_error: if (error)
trace_xfs_refcount_insert_error(cur, error, _RET_IP_); return error;
}
/* * Remove the record referred to by cur, then set the pointer to the spot * where the record could be re-inserted, in case we want to increment or * decrement the cursor. * This either works (return 0) or gets an EFSCORRUPTED error.
*/ STATICint
xfs_refcount_delete( struct xfs_btree_cur *cur, int *i)
{ struct xfs_refcount_irec irec; int found_rec; int error;
/* * Adjusting the Reference Count * * As stated elsewhere, the reference count btree (refcbt) stores * >1 reference counts for extents of physical blocks. In this * operation, we're either raising or lowering the reference count of * some subrange stored in the tree: * * <------ adjustment range ------> * ----+ +---+-----+ +--+--------+--------- * 2 | | 3 | 4 | |17| 55 | 10 * ----+ +---+-----+ +--+--------+--------- * X axis is physical blocks number; * reference counts are the numbers inside the rectangles * * The first thing we need to do is to ensure that there are no * refcount extents crossing either boundary of the range to be * adjusted. For any extent that does cross a boundary, split it into * two extents so that we can increment the refcount of one of the * pieces later: * * <------ adjustment range ------> * ----+ +---+-----+ +--+--------+----+---- * 2 | | 3 | 2 | |17| 55 | 10 | 10 * ----+ +---+-----+ +--+--------+----+---- * * For this next step, let's assume that all the physical blocks in * the adjustment range are mapped to a file and are therefore in use * at least once. Therefore, we can infer that any gap in the * refcount tree within the adjustment range represents a physical * extent with refcount == 1: * * <------ adjustment range ------> * ----+---+---+-----+-+--+--------+----+---- * 2 |"1"| 3 | 2 |1|17| 55 | 10 | 10 * ----+---+---+-----+-+--+--------+----+---- * ^ * * For each extent that falls within the interval range, figure out * which extent is to the left or the right of that extent. Now we * have a left, current, and right extent. If the new reference count * of the center extent enables us to merge left, center, and right * into one record covering all three, do so. If the center extent is * at the left end of the range, abuts the left extent, and its new * reference count matches the left extent's record, then merge them. * If the center extent is at the right end of the range, abuts the * right extent, and the reference counts match, merge those. In the * example, we can left merge (assuming an increment operation): * * <------ adjustment range ------> * --------+---+-----+-+--+--------+----+---- * 2 | 3 | 2 |1|17| 55 | 10 | 10 * --------+---+-----+-+--+--------+----+---- * ^ * * For all other extents within the range, adjust the reference count * or delete it if the refcount falls below 2. If we were * incrementing, the end result looks like this: * * <------ adjustment range ------> * --------+---+-----+-+--+--------+----+---- * 2 | 4 | 3 |2|18| 56 | 11 | 10 * --------+---+-----+-+--+--------+----+---- * * The result of a decrement operation looks as such: * * <------ adjustment range ------> * ----+ +---+ +--+--------+----+---- * 2 | | 2 | |16| 54 | 9 | 10 * ----+ +---+ +--+--------+----+---- * DDDD 111111DD * * The blocks marked "D" are freed; the blocks marked "1" are only * referenced once and therefore the record is removed from the * refcount btree.
*/
/* Next block after this extent. */ staticinline xfs_agblock_t
xfs_refc_next( struct xfs_refcount_irec *rc)
{ return rc->rc_startblock + rc->rc_blockcount;
}
/* * Split a refcount extent that crosses agbno.
*/ STATICint
xfs_refcount_split_extent( struct xfs_btree_cur *cur, enum xfs_refc_domain domain,
xfs_agblock_t agbno, bool *shape_changed)
{ struct xfs_refcount_irec rcext, tmp; int found_rec; int error;
*shape_changed = false;
error = xfs_refcount_lookup_le(cur, domain, agbno, &found_rec); if (error) goto out_error; if (!found_rec) return 0;
error = xfs_refcount_get_rec(cur, &rcext, &found_rec); if (error) goto out_error; if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
xfs_btree_mark_sick(cur);
error = -EFSCORRUPTED; goto out_error;
} if (rcext.rc_domain != domain) return 0; if (rcext.rc_startblock == agbno || xfs_refc_next(&rcext) <= agbno) return 0;
/* * Make sure the center and right extents are not in the btree. * If the center extent was synthesized, the first delete call * removes the right extent and we skip the second deletion. * If center and right were in the btree, then the first delete * call removes the center and the second one removes the right * extent.
*/
error = xfs_refcount_lookup_ge(cur, center->rc_domain,
center->rc_startblock, &found_rec); if (error) goto out_error; if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
xfs_btree_mark_sick(cur);
error = -EFSCORRUPTED; goto out_error;
}
/* * Find the left extent and the one after it (cleft). This function assumes * that we've already split any extent crossing agbno.
*/ STATICint
xfs_refcount_find_left_extents( struct xfs_btree_cur *cur, struct xfs_refcount_irec *left, struct xfs_refcount_irec *cleft, enum xfs_refc_domain domain,
xfs_agblock_t agbno,
xfs_extlen_t aglen)
{ struct xfs_refcount_irec tmp; int error; int found_rec;
if (tmp.rc_domain != domain) return 0; if (xfs_refc_next(&tmp) != agbno) return 0; /* We have a left extent; retrieve (or invent) the next right one */
*left = tmp;
error = xfs_btree_increment(cur, 0, &found_rec); if (error) goto out_error; if (found_rec) {
error = xfs_refcount_get_rec(cur, &tmp, &found_rec); if (error) goto out_error; if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
xfs_btree_mark_sick(cur);
error = -EFSCORRUPTED; goto out_error;
}
if (tmp.rc_domain != domain) goto not_found;
/* if tmp starts at the end of our range, just use that */ if (tmp.rc_startblock == agbno)
*cleft = tmp; else { /* * There's a gap in the refcntbt at the start of the * range we're interested in (refcount == 1) so * synthesize the implied extent and pass it back. * We assume here that the agbno/aglen range was * passed in from a data fork extent mapping and * therefore is allocated to exactly one owner.
*/
cleft->rc_startblock = agbno;
cleft->rc_blockcount = min(aglen,
tmp.rc_startblock - agbno);
cleft->rc_refcount = 1;
cleft->rc_domain = domain;
}
} else {
not_found: /* * No extents, so pretend that there's one covering the whole * range.
*/
cleft->rc_startblock = agbno;
cleft->rc_blockcount = aglen;
cleft->rc_refcount = 1;
cleft->rc_domain = domain;
}
trace_xfs_refcount_find_left_extent(cur, left, cleft, agbno); return error;
/* * Find the right extent and the one before it (cright). This function * assumes that we've already split any extents crossing agbno + aglen.
*/ STATICint
xfs_refcount_find_right_extents( struct xfs_btree_cur *cur, struct xfs_refcount_irec *right, struct xfs_refcount_irec *cright, enum xfs_refc_domain domain,
xfs_agblock_t agbno,
xfs_extlen_t aglen)
{ struct xfs_refcount_irec tmp; int error; int found_rec;
if (tmp.rc_domain != domain) return 0; if (tmp.rc_startblock != agbno + aglen) return 0; /* We have a right extent; retrieve (or invent) the next left one */
*right = tmp;
error = xfs_btree_decrement(cur, 0, &found_rec); if (error) goto out_error; if (found_rec) {
error = xfs_refcount_get_rec(cur, &tmp, &found_rec); if (error) goto out_error; if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
xfs_btree_mark_sick(cur);
error = -EFSCORRUPTED; goto out_error;
}
if (tmp.rc_domain != domain) goto not_found;
/* if tmp ends at the end of our range, just use that */ if (xfs_refc_next(&tmp) == agbno + aglen)
*cright = tmp; else { /* * There's a gap in the refcntbt at the end of the * range we're interested in (refcount == 1) so * create the implied extent and pass it back. * We assume here that the agbno/aglen range was * passed in from a data fork extent mapping and * therefore is allocated to exactly one owner.
*/
cright->rc_startblock = max(agbno, xfs_refc_next(&tmp));
cright->rc_blockcount = right->rc_startblock -
cright->rc_startblock;
cright->rc_refcount = 1;
cright->rc_domain = domain;
}
} else {
not_found: /* * No extents, so pretend that there's one covering the whole * range.
*/
cright->rc_startblock = agbno;
cright->rc_blockcount = aglen;
cright->rc_refcount = 1;
cright->rc_domain = domain;
}
trace_xfs_refcount_find_right_extent(cur, cright, right,
agbno + aglen); return error;
/* * To merge with a center record, both shoulder records must be * adjacent to the record we want to adjust. This is only true if * find_left and find_right made all four records valid.
*/ if (!xfs_refc_valid(left) || !xfs_refc_valid(right) ||
!xfs_refc_valid(cleft) || !xfs_refc_valid(cright)) returnfalse;
/* There must only be one record for the entire range. */ if (!cleft_is_cright) returnfalse;
/* The shoulder record refcounts must match the new refcount. */
new_refcount = xfs_refc_merge_refcount(cleft, adjust); if (left->rc_refcount != new_refcount) returnfalse; if (right->rc_refcount != new_refcount) returnfalse;
/* * The new record cannot exceed the max length. ulen is a ULL as the * individual record block counts can be up to (u32 - 1) in length * hence we need to catch u32 addition overflows here.
*/
ulen += cleft->rc_blockcount + right->rc_blockcount; if (ulen >= XFS_REFC_LEN_MAX) returnfalse;
/* * For a left merge, the left shoulder record must be adjacent to the * start of the range. If this is true, find_left made left and cleft * contain valid contents.
*/ if (!xfs_refc_valid(left) || !xfs_refc_valid(cleft)) returnfalse;
/* Left shoulder record refcount must match the new refcount. */
new_refcount = xfs_refc_merge_refcount(cleft, adjust); if (left->rc_refcount != new_refcount) returnfalse;
/* * The new record cannot exceed the max length. ulen is a ULL as the * individual record block counts can be up to (u32 - 1) in length * hence we need to catch u32 addition overflows here.
*/
ulen += cleft->rc_blockcount; if (ulen >= XFS_REFC_LEN_MAX) returnfalse;
/* * For a right merge, the right shoulder record must be adjacent to the * end of the range. If this is true, find_right made cright and right * contain valid contents.
*/ if (!xfs_refc_valid(right) || !xfs_refc_valid(cright)) returnfalse;
/* Right shoulder record refcount must match the new refcount. */
new_refcount = xfs_refc_merge_refcount(cright, adjust); if (right->rc_refcount != new_refcount) returnfalse;
/* * The new record cannot exceed the max length. ulen is a ULL as the * individual record block counts can be up to (u32 - 1) in length * hence we need to catch u32 addition overflows here.
*/
ulen += cright->rc_blockcount; if (ulen >= XFS_REFC_LEN_MAX) returnfalse;
returntrue;
}
/* * Try to merge with any extents on the boundaries of the adjustment range.
*/ STATICint
xfs_refcount_merge_extents( struct xfs_btree_cur *cur, enum xfs_refc_domain domain,
xfs_agblock_t *agbno,
xfs_extlen_t *aglen, enum xfs_refc_adjust_op adjust, bool *shape_changed)
{ struct xfs_refcount_irec left = {0}, cleft = {0}; struct xfs_refcount_irec cright = {0}, right = {0}; int error; unsignedlonglong ulen; bool cequal;
*shape_changed = false; /* * Find the extent just below agbno [left], just above agbno [cleft], * just below (agbno + aglen) [cright], and just above (agbno + aglen) * [right].
*/
error = xfs_refcount_find_left_extents(cur, &left, &cleft, domain,
*agbno, *aglen); if (error) return error;
error = xfs_refcount_find_right_extents(cur, &right, &cright, domain,
*agbno, *aglen); if (error) return error;
/* No left or right extent to merge; exit. */ if (!xfs_refc_valid(&left) && !xfs_refc_valid(&right)) return 0;
/* Try to merge left, cleft, and right. cleft must == cright. */ if (xfs_refc_want_merge_center(&left, &cleft, &cright, &right, cequal,
adjust, &ulen)) {
*shape_changed = true; return xfs_refcount_merge_center_extents(cur, &left, &cleft,
&right, ulen, aglen);
}
/* Try to merge left and cleft. */ if (xfs_refc_want_merge_left(&left, &cleft, adjust)) {
*shape_changed = true;
error = xfs_refcount_merge_left_extent(cur, &left, &cleft,
agbno, aglen); if (error) return error;
/* * If we just merged left + cleft and cleft == cright, * we no longer have a cright to merge with right. We're done.
*/ if (cequal) return 0;
}
/* Try to merge cright and right. */ if (xfs_refc_want_merge_right(&cright, &right, adjust)) {
*shape_changed = true; return xfs_refcount_merge_right_extent(cur, &right, &cright,
aglen);
}
return 0;
}
/* * XXX: This is a pretty hand-wavy estimate. The penalty for guessing * true incorrectly is a shutdown FS; the penalty for guessing false * incorrectly is more transaction rolls than might be necessary. * Be conservative here.
*/ staticbool
xfs_refcount_still_have_space( struct xfs_btree_cur *cur)
{ unsignedlong overhead;
/* * Worst case estimate: full splits of the free space and rmap btrees * to handle each of the shape changes to the refcount btree.
*/
overhead = xfs_allocfree_block_count(cur->bc_mp,
cur->bc_refc.shape_changes);
overhead += cur->bc_maxlevels;
overhead *= cur->bc_mp->m_sb.sb_blocksize;
/* * Only allow 2 refcount extent updates per transaction if the * refcount continue update "error" has been injected.
*/ if (cur->bc_refc.nr_ops > 2 &&
XFS_TEST_ERROR(false, cur->bc_mp,
XFS_ERRTAG_REFCOUNT_CONTINUE_UPDATE)) returnfalse;
/* * Adjust the refcounts of middle extents. At this point we should have * split extents that crossed the adjustment range; merged with adjacent * extents; and updated agbno/aglen to reflect the merges. Therefore, * all we have to do is update the extents inside [agbno, agbno + aglen].
*/ STATICint
xfs_refcount_adjust_extents( struct xfs_btree_cur *cur,
xfs_agblock_t *agbno,
xfs_extlen_t *aglen, enum xfs_refc_adjust_op adj)
{ struct xfs_refcount_irec ext, tmp; int error; int found_rec, found_tmp;
/* Merging did all the work already. */ if (*aglen == 0) return 0;
error = xfs_refcount_lookup_ge(cur, XFS_REFC_DOMAIN_SHARED, *agbno,
&found_rec); if (error) goto out_error;
/* * Deal with a hole in the refcount tree; if a file maps to * these blocks and there's no refcountbt record, pretend that * there is one with refcount == 1.
*/ if (ext.rc_startblock != *agbno) {
tmp.rc_startblock = *agbno;
tmp.rc_blockcount = min(*aglen,
ext.rc_startblock - *agbno);
tmp.rc_refcount = 1 + adj;
tmp.rc_domain = XFS_REFC_DOMAIN_SHARED;
trace_xfs_refcount_modify_extent(cur, &tmp);
/* * Either cover the hole (increment) or * delete the range (decrement).
*/
cur->bc_refc.nr_ops++; if (tmp.rc_refcount) {
error = xfs_refcount_insert(cur, &tmp,
&found_tmp); if (error) goto out_error; if (XFS_IS_CORRUPT(cur->bc_mp,
found_tmp != 1)) {
xfs_btree_mark_sick(cur);
error = -EFSCORRUPTED; goto out_error;
}
} else {
error = xrefc_free_extent(cur, &tmp); if (error) goto out_error;
}
/* Stop if there's nothing left to modify */ if (*aglen == 0 || !xfs_refcount_still_have_space(cur)) break;
/* Move the cursor to the start of ext. */
error = xfs_refcount_lookup_ge(cur,
XFS_REFC_DOMAIN_SHARED, *agbno,
&found_rec); if (error) goto out_error;
}
/* * A previous step trimmed agbno/aglen such that the end of the * range would not be in the middle of the record. If this is * no longer the case, something is seriously wrong with the * btree. Make sure we never feed the synthesized record into * the processing loop below.
*/ if (XFS_IS_CORRUPT(cur->bc_mp, ext.rc_blockcount == 0) ||
XFS_IS_CORRUPT(cur->bc_mp, ext.rc_blockcount > *aglen)) {
xfs_btree_mark_sick(cur);
error = -EFSCORRUPTED; goto out_error;
}
/* * Adjust the reference count and either update the tree * (incr) or free the blocks (decr).
*/ if (ext.rc_refcount == XFS_REFC_REFCOUNT_MAX) goto skip;
ext.rc_refcount += adj;
trace_xfs_refcount_modify_extent(cur, &ext);
cur->bc_refc.nr_ops++; if (ext.rc_refcount > 1) {
error = xfs_refcount_update(cur, &ext); if (error) goto out_error;
} elseif (ext.rc_refcount == 1) {
error = xfs_refcount_delete(cur, &found_rec); if (error) goto out_error; if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
xfs_btree_mark_sick(cur);
error = -EFSCORRUPTED; goto out_error;
} goto advloop;
} else {
error = xrefc_free_extent(cur, &ext); if (error) goto out_error;
}
skip:
error = xfs_btree_increment(cur, 0, &found_rec); if (error) goto out_error;
/* Adjust the reference count of a range of AG blocks. */ STATICint
xfs_refcount_adjust( struct xfs_btree_cur *cur,
xfs_agblock_t *agbno,
xfs_extlen_t *aglen, enum xfs_refc_adjust_op adj)
{ bool shape_changed; int shape_changes = 0; int error;
/* * Ensure that no rcextents cross the boundary of the adjustment range.
*/
error = xfs_refcount_split_extent(cur, XFS_REFC_DOMAIN_SHARED,
*agbno, &shape_changed); if (error) goto out_error; if (shape_changed)
shape_changes++;
error = xfs_refcount_split_extent(cur, XFS_REFC_DOMAIN_SHARED,
*agbno + *aglen, &shape_changed); if (error) goto out_error; if (shape_changed)
shape_changes++;
/* * Try to merge with the left or right extents of the range.
*/
error = xfs_refcount_merge_extents(cur, XFS_REFC_DOMAIN_SHARED,
agbno, aglen, adj, &shape_changed); if (error) goto out_error; if (shape_changed)
shape_changes++; if (shape_changes)
cur->bc_refc.shape_changes++;
/* Now that we've taken care of the ends, adjust the middle extents */
error = xfs_refcount_adjust_extents(cur, agbno, aglen, adj); if (error) goto out_error;
/* * Set up a continuation a deferred refcount operation by updating the intent. * Checks to make sure we're not going to run off the end of the AG.
*/ staticinlineint
xfs_refcount_continue_op( struct xfs_btree_cur *cur, struct xfs_refcount_intent *ri,
xfs_agblock_t new_agbno)
{ struct xfs_mount *mp = cur->bc_mp; struct xfs_perag *pag = to_perag(cur->bc_group);
if (XFS_IS_CORRUPT(mp, !xfs_verify_agbext(pag, new_agbno,
ri->ri_blockcount))) {
xfs_btree_mark_sick(cur); return -EFSCORRUPTED;
}
/* * Process one of the deferred refcount operations. We pass back the * btree cursor to maintain our lock on the btree between calls. * This saves time and eliminates a buffer deadlock between the * superblock and the AGF because we'll always grab them in the same * order.
*/ int
xfs_refcount_finish_one( struct xfs_trans *tp, struct xfs_refcount_intent *ri, struct xfs_btree_cur **pcur)
{ struct xfs_mount *mp = tp->t_mountp; struct xfs_btree_cur *rcur = *pcur; struct xfs_buf *agbp = NULL; int error = 0;
xfs_agblock_t bno; unsignedlong nr_ops = 0; int shape_changes = 0;
bno = XFS_FSB_TO_AGBNO(mp, ri->ri_startblock);
trace_xfs_refcount_deferred(mp, ri);
if (XFS_TEST_ERROR(false, mp, XFS_ERRTAG_REFCOUNT_FINISH_ONE)) return -EIO;
/* * If we haven't gotten a cursor or the cursor AG doesn't match * the startblock, get one now.
*/ if (rcur != NULL && rcur->bc_group != ri->ri_group) {
nr_ops = rcur->bc_refc.nr_ops;
shape_changes = rcur->bc_refc.shape_changes;
xfs_btree_del_cursor(rcur, 0);
rcur = NULL;
*pcur = NULL;
} if (rcur == NULL) { struct xfs_perag *pag = to_perag(ri->ri_group);
error = xfs_alloc_read_agf(pag, tp,
XFS_ALLOC_FLAG_FREEING, &agbp); if (error) return error;
switch (ri->ri_type) { case XFS_REFCOUNT_INCREASE:
error = xfs_refcount_adjust(rcur, &bno, &ri->ri_blockcount,
XFS_REFCOUNT_ADJUST_INCREASE); if (error) return error; if (ri->ri_blockcount > 0)
error = xfs_refcount_continue_op(rcur, ri, bno); break; case XFS_REFCOUNT_DECREASE:
error = xfs_refcount_adjust(rcur, &bno, &ri->ri_blockcount,
XFS_REFCOUNT_ADJUST_DECREASE); if (error) return error; if (ri->ri_blockcount > 0)
error = xfs_refcount_continue_op(rcur, ri, bno); break; case XFS_REFCOUNT_ALLOC_COW:
error = __xfs_refcount_cow_alloc(rcur, bno, ri->ri_blockcount); if (error) return error;
ri->ri_blockcount = 0; break; case XFS_REFCOUNT_FREE_COW:
error = __xfs_refcount_cow_free(rcur, bno, ri->ri_blockcount); if (error) return error;
ri->ri_blockcount = 0; break; default:
ASSERT(0); return -EFSCORRUPTED;
} if (!error && ri->ri_blockcount > 0)
trace_xfs_refcount_finish_one_leftover(mp, ri); return error;
}
/* * Set up a continuation a deferred rtrefcount operation by updating the * intent. Checks to make sure we're not going to run off the end of the * rtgroup.
*/ staticinlineint
xfs_rtrefcount_continue_op( struct xfs_btree_cur *cur, struct xfs_refcount_intent *ri,
xfs_agblock_t new_agbno)
{ struct xfs_mount *mp = cur->bc_mp; struct xfs_rtgroup *rtg = to_rtg(ri->ri_group);
if (XFS_IS_CORRUPT(mp, !xfs_verify_rgbext(rtg, new_agbno,
ri->ri_blockcount))) {
xfs_btree_mark_sick(cur); return -EFSCORRUPTED;
}
/* * Process one of the deferred realtime refcount operations. We pass back the * btree cursor to maintain our lock on the btree between calls.
*/ int
xfs_rtrefcount_finish_one( struct xfs_trans *tp, struct xfs_refcount_intent *ri, struct xfs_btree_cur **pcur)
{ struct xfs_mount *mp = tp->t_mountp; struct xfs_rtgroup *rtg = to_rtg(ri->ri_group); struct xfs_btree_cur *rcur = *pcur; int error = 0;
xfs_rgblock_t bno; unsignedlong nr_ops = 0; int shape_changes = 0;
bno = xfs_rtb_to_rgbno(mp, ri->ri_startblock);
trace_xfs_refcount_deferred(mp, ri);
if (XFS_TEST_ERROR(false, mp, XFS_ERRTAG_REFCOUNT_FINISH_ONE)) return -EIO;
/* * If we haven't gotten a cursor or the cursor AG doesn't match * the startblock, get one now.
*/ if (rcur != NULL && rcur->bc_group != ri->ri_group) {
nr_ops = rcur->bc_refc.nr_ops;
shape_changes = rcur->bc_refc.shape_changes;
xfs_btree_del_cursor(rcur, 0);
rcur = NULL;
*pcur = NULL;
} if (rcur == NULL) {
xfs_rtgroup_lock(rtg, XFS_RTGLOCK_REFCOUNT);
xfs_rtgroup_trans_join(tp, rtg, XFS_RTGLOCK_REFCOUNT);
*pcur = rcur = xfs_rtrefcountbt_init_cursor(tp, rtg);
/* * Given an AG extent, find the lowest-numbered run of shared blocks * within that range and return the range in fbno/flen. If * find_end_of_shared is set, return the longest contiguous extent of * shared blocks; if not, just return the first extent we find. If no * shared blocks are found, fbno and flen will be set to NULLAGBLOCK * and 0, respectively.
*/ int
xfs_refcount_find_shared( struct xfs_btree_cur *cur,
xfs_agblock_t agbno,
xfs_extlen_t aglen,
xfs_agblock_t *fbno,
xfs_extlen_t *flen, bool find_end_of_shared)
{ struct xfs_refcount_irec tmp; int i; int have; int error;
/* By default, skip the whole range */
*fbno = NULLAGBLOCK;
*flen = 0;
/* Try to find a refcount extent that crosses the start */
error = xfs_refcount_lookup_le(cur, XFS_REFC_DOMAIN_SHARED, agbno,
&have); if (error) goto out_error; if (!have) { /* No left extent, look at the next one */
error = xfs_btree_increment(cur, 0, &have); if (error) goto out_error; if (!have) goto done;
}
error = xfs_refcount_get_rec(cur, &tmp, &i); if (error) goto out_error; if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
xfs_btree_mark_sick(cur);
error = -EFSCORRUPTED; goto out_error;
} if (tmp.rc_domain != XFS_REFC_DOMAIN_SHARED) goto done;
/* If the extent ends before the start, look at the next one */ if (tmp.rc_startblock + tmp.rc_blockcount <= agbno) {
error = xfs_btree_increment(cur, 0, &have); if (error) goto out_error; if (!have) goto done;
error = xfs_refcount_get_rec(cur, &tmp, &i); if (error) goto out_error; if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
xfs_btree_mark_sick(cur);
error = -EFSCORRUPTED; goto out_error;
} if (tmp.rc_domain != XFS_REFC_DOMAIN_SHARED) goto done;
}
/* If the extent starts after the range we want, bail out */ if (tmp.rc_startblock >= agbno + aglen) goto done;
/* We found the start of a shared extent! */ if (tmp.rc_startblock < agbno) {
tmp.rc_blockcount -= (agbno - tmp.rc_startblock);
tmp.rc_startblock = agbno;
}
out_error: if (error)
trace_xfs_refcount_find_shared_error(cur, error, _RET_IP_); return error;
}
/* * Recovering CoW Blocks After a Crash * * Due to the way that the copy on write mechanism works, there's a window of * opportunity in which we can lose track of allocated blocks during a crash. * Because CoW uses delayed allocation in the in-core CoW fork, writeback * causes blocks to be allocated and stored in the CoW fork. The blocks are * no longer in the free space btree but are not otherwise recorded anywhere * until the write completes and the blocks are mapped into the file. A crash * in between allocation and remapping results in the replacement blocks being * lost. This situation is exacerbated by the CoW extent size hint because * allocations can hang around for long time. * * However, there is a place where we can record these allocations before they * become mappings -- the reference count btree. The btree does not record * extents with refcount == 1, so we can record allocations with a refcount of * 1. Blocks being used for CoW writeout cannot be shared, so there should be * no conflict with shared block records. These mappings should be created * when we allocate blocks to the CoW fork and deleted when they're removed * from the CoW fork. * * Minor nit: records for in-progress CoW allocations and records for shared * extents must never be merged, to preserve the property that (except for CoW * allocations) there are no refcount btree entries with refcount == 1. The * only time this could potentially happen is when unsharing a block that's * adjacent to CoW allocations, so we must be careful to avoid this. * * At mount time we recover lost CoW allocations by searching the refcount * btree for these refcount == 1 mappings. These represent CoW allocations * that were in progress at the time the filesystem went down, so we can free * them to get the space back. * * This mechanism is superior to creating EFIs for unmapped CoW extents for * several reasons -- first, EFIs pin the tail of the log and would have to be * periodically relogged to avoid filling up the log. Second, CoW completions * will have to file an EFD and create new EFIs for whatever remains in the * CoW fork; this partially takes care of (1) but extent-size reservations * will have to periodically relog even if there's no writeout in progress. * This can happen if the CoW extent size hint is set, which you really want. * Third, EFIs cannot currently be automatically relogged into newer * transactions to advance the log tail. Fourth, stuffing the log full of * EFIs places an upper bound on the number of CoW allocations that can be * held filesystem-wide at any given time. Recording them in the refcount * btree doesn't require us to maintain any state in memory and doesn't pin * the log.
*/ /* * Adjust the refcounts of CoW allocations. These allocations are "magic" * in that they're not referenced anywhere else in the filesystem, so we * stash them in the refcount btree with a refcount of 1 until either file * remapping (or CoW cancellation) happens.
*/ STATICint
xfs_refcount_adjust_cow_extents( struct xfs_btree_cur *cur,
xfs_agblock_t agbno,
xfs_extlen_t aglen, enum xfs_refc_adjust_op adj)
{ struct xfs_refcount_irec ext, tmp; int error; int found_rec, found_tmp;
if (aglen == 0) return 0;
/* Find any overlapping refcount records */
error = xfs_refcount_lookup_ge(cur, XFS_REFC_DOMAIN_COW, agbno,
&found_rec); if (error) goto out_error;
error = xfs_refcount_get_rec(cur, &ext, &found_rec); if (error) goto out_error; if (XFS_IS_CORRUPT(cur->bc_mp, found_rec &&
ext.rc_domain != XFS_REFC_DOMAIN_COW)) {
xfs_btree_mark_sick(cur);
error = -EFSCORRUPTED; goto out_error;
} if (!found_rec) {
ext.rc_startblock = xfs_group_max_blocks(cur->bc_group);
ext.rc_blockcount = 0;
ext.rc_refcount = 0;
ext.rc_domain = XFS_REFC_DOMAIN_COW;
}
switch (adj) { case XFS_REFCOUNT_ADJUST_COW_ALLOC: /* Adding a CoW reservation, there should be nothing here. */ if (XFS_IS_CORRUPT(cur->bc_mp,
agbno + aglen > ext.rc_startblock)) {
xfs_btree_mark_sick(cur);
error = -EFSCORRUPTED; goto out_error;
}
/* * Add or remove refcount btree entries for CoW reservations.
*/ STATICint
xfs_refcount_adjust_cow( struct xfs_btree_cur *cur,
xfs_agblock_t agbno,
xfs_extlen_t aglen, enum xfs_refc_adjust_op adj)
{ bool shape_changed; int error;
/* * Ensure that no rcextents cross the boundary of the adjustment range.
*/
error = xfs_refcount_split_extent(cur, XFS_REFC_DOMAIN_COW,
agbno, &shape_changed); if (error) goto out_error;
/* * Try to merge with the left or right extents of the range.
*/
error = xfs_refcount_merge_extents(cur, XFS_REFC_DOMAIN_COW, &agbno,
&aglen, adj, &shape_changed); if (error) goto out_error;
/* Now that we've taken care of the ends, adjust the middle extents */
error = xfs_refcount_adjust_cow_extents(cur, agbno, aglen, adj); if (error) goto out_error;
/* reflink filesystems must not have groups larger than 2^31-1 blocks */
BUILD_BUG_ON(XFS_MAX_RGBLOCKS >= XFS_REFC_COWFLAG);
BUILD_BUG_ON(XFS_MAX_CRC_AG_BLOCKS >= XFS_REFC_COWFLAG);
if (isrt) { if (!xfs_has_rtgroups(mp)) return 0; if (xfs_group_max_blocks(xg) >= XFS_MAX_RGBLOCKS) return -EOPNOTSUPP;
} else { if (xfs_group_max_blocks(xg) > XFS_MAX_CRC_AG_BLOCKS) return -EOPNOTSUPP;
}
INIT_LIST_HEAD(&debris);
/* * In this first part, we use an empty transaction to gather up * all the leftover CoW extents so that we can subsequently * delete them. The empty transaction is used to avoid * a buffer lock deadlock if there happens to be a loop in the * refcountbt because we're allowed to re-grab a buffer that is * already attached to our transaction. When we're done * recording the CoW debris we cancel the (empty) transaction * and everything goes away cleanly.
*/
tp = xfs_trans_alloc_empty(mp);
if (isrt) {
xfs_rtgroup_lock(to_rtg(xg), XFS_RTGLOCK_REFCOUNT);
cur = xfs_rtrefcountbt_init_cursor(tp, to_rtg(xg));
} else {
error = xfs_alloc_read_agf(to_perag(xg), tp, 0, &agbp); if (error) goto out_trans;
cur = xfs_refcountbt_init_cursor(mp, tp, agbp, to_perag(xg));
}
/* Find all the leftover CoW staging extents. */
error = xfs_btree_query_range(cur, &low, &high,
xfs_refcount_recover_extent, &debris);
xfs_btree_del_cursor(cur, error); if (agbp)
xfs_trans_brelse(tp, agbp); else
xfs_rtgroup_unlock(to_rtg(xg), XFS_RTGLOCK_REFCOUNT);
xfs_trans_cancel(tp); if (error) goto out_free;
/* Now iterate the list to free the leftovers */
list_for_each_entry_safe(rr, n, &debris, rr_list) { /* Set up transaction. */
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, 0, 0, 0, &tp); if (error) goto out_free;
/* Free the orphan record */
fsb = xfs_gbno_to_fsb(xg, rr->rr_rrec.rc_startblock);
xfs_refcount_free_cow_extent(tp, isrt, fsb,
rr->rr_rrec.rc_blockcount);
error = xfs_trans_commit(tp); if (error) goto out_free;
list_del(&rr->rr_list);
kfree(rr);
}
return error;
out_trans:
xfs_trans_cancel(tp);
out_free: /* Free the leftover list */
list_for_each_entry_safe(rr, n, &debris, rr_list) {
list_del(&rr->rr_list);
kfree(rr);
} return error;
}
/* * Scan part of the keyspace of the refcount records and tell us if the area * has no records, is fully mapped by records, or is partially filled.
*/ int
xfs_refcount_has_records( struct xfs_btree_cur *cur, enum xfs_refc_domain domain,
xfs_agblock_t bno,
xfs_extlen_t len, enum xbtree_recpacking *outcome)
{ union xfs_btree_irec low; union xfs_btree_irec high;
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