| // SPDX-License-Identifier: GPL-2.0+ |
| /* |
| * Copyright (C) 2016 Oracle. All Rights Reserved. |
| * Author: Darrick J. Wong <darrick.wong@oracle.com> |
| */ |
| #include "xfs.h" |
| #include "xfs_fs.h" |
| #include "xfs_shared.h" |
| #include "xfs_format.h" |
| #include "xfs_log_format.h" |
| #include "xfs_trans_resv.h" |
| #include "xfs_sb.h" |
| #include "xfs_mount.h" |
| #include "xfs_defer.h" |
| #include "xfs_btree.h" |
| #include "xfs_bmap.h" |
| #include "xfs_refcount_btree.h" |
| #include "xfs_alloc.h" |
| #include "xfs_errortag.h" |
| #include "xfs_error.h" |
| #include "xfs_trace.h" |
| #include "xfs_cksum.h" |
| #include "xfs_trans.h" |
| #include "xfs_bit.h" |
| #include "xfs_refcount.h" |
| #include "xfs_rmap.h" |
| |
| /* Allowable refcount adjustment amounts. */ |
| enum xfs_refc_adjust_op { |
| XFS_REFCOUNT_ADJUST_INCREASE = 1, |
| XFS_REFCOUNT_ADJUST_DECREASE = -1, |
| XFS_REFCOUNT_ADJUST_COW_ALLOC = 0, |
| XFS_REFCOUNT_ADJUST_COW_FREE = -1, |
| }; |
| |
| STATIC int __xfs_refcount_cow_alloc(struct xfs_btree_cur *rcur, |
| xfs_agblock_t agbno, xfs_extlen_t aglen, |
| struct xfs_defer_ops *dfops); |
| STATIC int __xfs_refcount_cow_free(struct xfs_btree_cur *rcur, |
| xfs_agblock_t agbno, xfs_extlen_t aglen, |
| struct xfs_defer_ops *dfops); |
| |
| /* |
| * 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, |
| xfs_agblock_t bno, |
| int *stat) |
| { |
| trace_xfs_refcount_lookup(cur->bc_mp, cur->bc_private.a.agno, bno, |
| XFS_LOOKUP_LE); |
| cur->bc_rec.rc.rc_startblock = bno; |
| cur->bc_rec.rc.rc_blockcount = 0; |
| 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, |
| xfs_agblock_t bno, |
| int *stat) |
| { |
| trace_xfs_refcount_lookup(cur->bc_mp, cur->bc_private.a.agno, bno, |
| XFS_LOOKUP_GE); |
| cur->bc_rec.rc.rc_startblock = bno; |
| cur->bc_rec.rc.rc_blockcount = 0; |
| 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, |
| xfs_agblock_t bno, |
| int *stat) |
| { |
| trace_xfs_refcount_lookup(cur->bc_mp, cur->bc_private.a.agno, bno, |
| XFS_LOOKUP_LE); |
| cur->bc_rec.rc.rc_startblock = bno; |
| cur->bc_rec.rc.rc_blockcount = 0; |
| return xfs_btree_lookup(cur, XFS_LOOKUP_EQ, stat); |
| } |
| |
| /* Convert on-disk record to in-core format. */ |
| void |
| xfs_refcount_btrec_to_irec( |
| union xfs_btree_rec *rec, |
| struct xfs_refcount_irec *irec) |
| { |
| irec->rc_startblock = be32_to_cpu(rec->refc.rc_startblock); |
| irec->rc_blockcount = be32_to_cpu(rec->refc.rc_blockcount); |
| irec->rc_refcount = be32_to_cpu(rec->refc.rc_refcount); |
| } |
| |
| /* |
| * 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) |
| { |
| struct xfs_mount *mp = cur->bc_mp; |
| xfs_agnumber_t agno = cur->bc_private.a.agno; |
| union xfs_btree_rec *rec; |
| int error; |
| xfs_agblock_t realstart; |
| |
| error = xfs_btree_get_rec(cur, &rec, stat); |
| if (error || !*stat) |
| return error; |
| |
| xfs_refcount_btrec_to_irec(rec, irec); |
| |
| agno = cur->bc_private.a.agno; |
| if (irec->rc_blockcount == 0 || irec->rc_blockcount > MAXREFCEXTLEN) |
| goto out_bad_rec; |
| |
| /* handle special COW-staging state */ |
| realstart = irec->rc_startblock; |
| if (realstart & XFS_REFC_COW_START) { |
| if (irec->rc_refcount != 1) |
| goto out_bad_rec; |
| realstart &= ~XFS_REFC_COW_START; |
| } else if (irec->rc_refcount < 2) { |
| goto out_bad_rec; |
| } |
| |
| /* check for valid extent range, including overflow */ |
| if (!xfs_verify_agbno(mp, agno, realstart)) |
| goto out_bad_rec; |
| if (realstart > realstart + irec->rc_blockcount) |
| goto out_bad_rec; |
| if (!xfs_verify_agbno(mp, agno, realstart + irec->rc_blockcount - 1)) |
| goto out_bad_rec; |
| |
| if (irec->rc_refcount == 0 || irec->rc_refcount > MAXREFCOUNT) |
| goto out_bad_rec; |
| |
| trace_xfs_refcount_get(cur->bc_mp, cur->bc_private.a.agno, irec); |
| return 0; |
| |
| out_bad_rec: |
| xfs_warn(mp, |
| "Refcount BTree record corruption in AG %d detected!", agno); |
| xfs_warn(mp, |
| "Start block 0x%x, block count 0x%x, references 0x%x", |
| irec->rc_startblock, irec->rc_blockcount, irec->rc_refcount); |
| return -EFSCORRUPTED; |
| } |
| |
| /* |
| * 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. |
| */ |
| STATIC int |
| xfs_refcount_update( |
| struct xfs_btree_cur *cur, |
| struct xfs_refcount_irec *irec) |
| { |
| union xfs_btree_rec rec; |
| int error; |
| |
| trace_xfs_refcount_update(cur->bc_mp, cur->bc_private.a.agno, irec); |
| rec.refc.rc_startblock = cpu_to_be32(irec->rc_startblock); |
| rec.refc.rc_blockcount = cpu_to_be32(irec->rc_blockcount); |
| rec.refc.rc_refcount = cpu_to_be32(irec->rc_refcount); |
| error = xfs_btree_update(cur, &rec); |
| if (error) |
| trace_xfs_refcount_update_error(cur->bc_mp, |
| cur->bc_private.a.agno, error, _RET_IP_); |
| return 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; |
| |
| trace_xfs_refcount_insert(cur->bc_mp, cur->bc_private.a.agno, irec); |
| cur->bc_rec.rc.rc_startblock = irec->rc_startblock; |
| cur->bc_rec.rc.rc_blockcount = irec->rc_blockcount; |
| cur->bc_rec.rc.rc_refcount = irec->rc_refcount; |
| error = xfs_btree_insert(cur, i); |
| if (error) |
| goto out_error; |
| XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, *i == 1, out_error); |
| |
| out_error: |
| if (error) |
| trace_xfs_refcount_insert_error(cur->bc_mp, |
| cur->bc_private.a.agno, 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. |
| */ |
| STATIC int |
| xfs_refcount_delete( |
| struct xfs_btree_cur *cur, |
| int *i) |
| { |
| struct xfs_refcount_irec irec; |
| int found_rec; |
| int error; |
| |
| error = xfs_refcount_get_rec(cur, &irec, &found_rec); |
| if (error) |
| goto out_error; |
| XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1, out_error); |
| trace_xfs_refcount_delete(cur->bc_mp, cur->bc_private.a.agno, &irec); |
| error = xfs_btree_delete(cur, i); |
| XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, *i == 1, out_error); |
| if (error) |
| goto out_error; |
| error = xfs_refcount_lookup_ge(cur, irec.rc_startblock, &found_rec); |
| out_error: |
| if (error) |
| trace_xfs_refcount_delete_error(cur->bc_mp, |
| cur->bc_private.a.agno, error, _RET_IP_); |
| return 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. */ |
| static inline 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. |
| */ |
| STATIC int |
| xfs_refcount_split_extent( |
| struct xfs_btree_cur *cur, |
| 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, 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; |
| XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1, out_error); |
| if (rcext.rc_startblock == agbno || xfs_refc_next(&rcext) <= agbno) |
| return 0; |
| |
| *shape_changed = true; |
| trace_xfs_refcount_split_extent(cur->bc_mp, cur->bc_private.a.agno, |
| &rcext, agbno); |
| |
| /* Establish the right extent. */ |
| tmp = rcext; |
| tmp.rc_startblock = agbno; |
| tmp.rc_blockcount -= (agbno - rcext.rc_startblock); |
| error = xfs_refcount_update(cur, &tmp); |
| if (error) |
| goto out_error; |
| |
| /* Insert the left extent. */ |
| tmp = rcext; |
| tmp.rc_blockcount = agbno - rcext.rc_startblock; |
| error = xfs_refcount_insert(cur, &tmp, &found_rec); |
| if (error) |
| goto out_error; |
| XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1, out_error); |
| return error; |
| |
| out_error: |
| trace_xfs_refcount_split_extent_error(cur->bc_mp, |
| cur->bc_private.a.agno, error, _RET_IP_); |
| return error; |
| } |
| |
| /* |
| * Merge the left, center, and right extents. |
| */ |
| STATIC int |
| xfs_refcount_merge_center_extents( |
| struct xfs_btree_cur *cur, |
| struct xfs_refcount_irec *left, |
| struct xfs_refcount_irec *center, |
| struct xfs_refcount_irec *right, |
| unsigned long long extlen, |
| xfs_extlen_t *aglen) |
| { |
| int error; |
| int found_rec; |
| |
| trace_xfs_refcount_merge_center_extents(cur->bc_mp, |
| cur->bc_private.a.agno, left, center, right); |
| |
| /* |
| * 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_startblock, |
| &found_rec); |
| if (error) |
| goto out_error; |
| XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1, out_error); |
| |
| error = xfs_refcount_delete(cur, &found_rec); |
| if (error) |
| goto out_error; |
| XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1, out_error); |
| |
| if (center->rc_refcount > 1) { |
| error = xfs_refcount_delete(cur, &found_rec); |
| if (error) |
| goto out_error; |
| XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1, |
| out_error); |
| } |
| |
| /* Enlarge the left extent. */ |
| error = xfs_refcount_lookup_le(cur, left->rc_startblock, |
| &found_rec); |
| if (error) |
| goto out_error; |
| XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1, out_error); |
| |
| left->rc_blockcount = extlen; |
| error = xfs_refcount_update(cur, left); |
| if (error) |
| goto out_error; |
| |
| *aglen = 0; |
| return error; |
| |
| out_error: |
| trace_xfs_refcount_merge_center_extents_error(cur->bc_mp, |
| cur->bc_private.a.agno, error, _RET_IP_); |
| return error; |
| } |
| |
| /* |
| * Merge with the left extent. |
| */ |
| STATIC int |
| xfs_refcount_merge_left_extent( |
| struct xfs_btree_cur *cur, |
| struct xfs_refcount_irec *left, |
| struct xfs_refcount_irec *cleft, |
| xfs_agblock_t *agbno, |
| xfs_extlen_t *aglen) |
| { |
| int error; |
| int found_rec; |
| |
| trace_xfs_refcount_merge_left_extent(cur->bc_mp, |
| cur->bc_private.a.agno, left, cleft); |
| |
| /* If the extent at agbno (cleft) wasn't synthesized, remove it. */ |
| if (cleft->rc_refcount > 1) { |
| error = xfs_refcount_lookup_le(cur, cleft->rc_startblock, |
| &found_rec); |
| if (error) |
| goto out_error; |
| XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1, |
| out_error); |
| |
| error = xfs_refcount_delete(cur, &found_rec); |
| if (error) |
| goto out_error; |
| XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1, |
| out_error); |
| } |
| |
| /* Enlarge the left extent. */ |
| error = xfs_refcount_lookup_le(cur, left->rc_startblock, |
| &found_rec); |
| if (error) |
| goto out_error; |
| XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1, out_error); |
| |
| left->rc_blockcount += cleft->rc_blockcount; |
| error = xfs_refcount_update(cur, left); |
| if (error) |
| goto out_error; |
| |
| *agbno += cleft->rc_blockcount; |
| *aglen -= cleft->rc_blockcount; |
| return error; |
| |
| out_error: |
| trace_xfs_refcount_merge_left_extent_error(cur->bc_mp, |
| cur->bc_private.a.agno, error, _RET_IP_); |
| return error; |
| } |
| |
| /* |
| * Merge with the right extent. |
| */ |
| STATIC int |
| xfs_refcount_merge_right_extent( |
| struct xfs_btree_cur *cur, |
| struct xfs_refcount_irec *right, |
| struct xfs_refcount_irec *cright, |
| xfs_extlen_t *aglen) |
| { |
| int error; |
| int found_rec; |
| |
| trace_xfs_refcount_merge_right_extent(cur->bc_mp, |
| cur->bc_private.a.agno, cright, right); |
| |
| /* |
| * If the extent ending at agbno+aglen (cright) wasn't synthesized, |
| * remove it. |
| */ |
| if (cright->rc_refcount > 1) { |
| error = xfs_refcount_lookup_le(cur, cright->rc_startblock, |
| &found_rec); |
| if (error) |
| goto out_error; |
| XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1, |
| out_error); |
| |
| error = xfs_refcount_delete(cur, &found_rec); |
| if (error) |
| goto out_error; |
| XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1, |
| out_error); |
| } |
| |
| /* Enlarge the right extent. */ |
| error = xfs_refcount_lookup_le(cur, right->rc_startblock, |
| &found_rec); |
| if (error) |
| goto out_error; |
| XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1, out_error); |
| |
| right->rc_startblock -= cright->rc_blockcount; |
| right->rc_blockcount += cright->rc_blockcount; |
| error = xfs_refcount_update(cur, right); |
| if (error) |
| goto out_error; |
| |
| *aglen -= cright->rc_blockcount; |
| return error; |
| |
| out_error: |
| trace_xfs_refcount_merge_right_extent_error(cur->bc_mp, |
| cur->bc_private.a.agno, error, _RET_IP_); |
| return error; |
| } |
| |
| #define XFS_FIND_RCEXT_SHARED 1 |
| #define XFS_FIND_RCEXT_COW 2 |
| /* |
| * Find the left extent and the one after it (cleft). This function assumes |
| * that we've already split any extent crossing agbno. |
| */ |
| STATIC int |
| xfs_refcount_find_left_extents( |
| struct xfs_btree_cur *cur, |
| struct xfs_refcount_irec *left, |
| struct xfs_refcount_irec *cleft, |
| xfs_agblock_t agbno, |
| xfs_extlen_t aglen, |
| int flags) |
| { |
| struct xfs_refcount_irec tmp; |
| int error; |
| int found_rec; |
| |
| left->rc_startblock = cleft->rc_startblock = NULLAGBLOCK; |
| error = xfs_refcount_lookup_le(cur, agbno - 1, &found_rec); |
| if (error) |
| goto out_error; |
| if (!found_rec) |
| return 0; |
| |
| error = xfs_refcount_get_rec(cur, &tmp, &found_rec); |
| if (error) |
| goto out_error; |
| XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1, out_error); |
| |
| if (xfs_refc_next(&tmp) != agbno) |
| return 0; |
| if ((flags & XFS_FIND_RCEXT_SHARED) && tmp.rc_refcount < 2) |
| return 0; |
| if ((flags & XFS_FIND_RCEXT_COW) && tmp.rc_refcount > 1) |
| 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; |
| XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1, |
| out_error); |
| |
| /* 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; |
| } |
| } else { |
| /* |
| * No extents, so pretend that there's one covering the whole |
| * range. |
| */ |
| cleft->rc_startblock = agbno; |
| cleft->rc_blockcount = aglen; |
| cleft->rc_refcount = 1; |
| } |
| trace_xfs_refcount_find_left_extent(cur->bc_mp, cur->bc_private.a.agno, |
| left, cleft, agbno); |
| return error; |
| |
| out_error: |
| trace_xfs_refcount_find_left_extent_error(cur->bc_mp, |
| cur->bc_private.a.agno, error, _RET_IP_); |
| 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. |
| */ |
| STATIC int |
| xfs_refcount_find_right_extents( |
| struct xfs_btree_cur *cur, |
| struct xfs_refcount_irec *right, |
| struct xfs_refcount_irec *cright, |
| xfs_agblock_t agbno, |
| xfs_extlen_t aglen, |
| int flags) |
| { |
| struct xfs_refcount_irec tmp; |
| int error; |
| int found_rec; |
| |
| right->rc_startblock = cright->rc_startblock = NULLAGBLOCK; |
| error = xfs_refcount_lookup_ge(cur, agbno + aglen, &found_rec); |
| if (error) |
| goto out_error; |
| if (!found_rec) |
| return 0; |
| |
| error = xfs_refcount_get_rec(cur, &tmp, &found_rec); |
| if (error) |
| goto out_error; |
| XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1, out_error); |
| |
| if (tmp.rc_startblock != agbno + aglen) |
| return 0; |
| if ((flags & XFS_FIND_RCEXT_SHARED) && tmp.rc_refcount < 2) |
| return 0; |
| if ((flags & XFS_FIND_RCEXT_COW) && tmp.rc_refcount > 1) |
| 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; |
| XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1, |
| out_error); |
| |
| /* 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; |
| } |
| } else { |
| /* |
| * No extents, so pretend that there's one covering the whole |
| * range. |
| */ |
| cright->rc_startblock = agbno; |
| cright->rc_blockcount = aglen; |
| cright->rc_refcount = 1; |
| } |
| trace_xfs_refcount_find_right_extent(cur->bc_mp, cur->bc_private.a.agno, |
| cright, right, agbno + aglen); |
| return error; |
| |
| out_error: |
| trace_xfs_refcount_find_right_extent_error(cur->bc_mp, |
| cur->bc_private.a.agno, error, _RET_IP_); |
| return error; |
| } |
| |
| /* Is this extent valid? */ |
| static inline bool |
| xfs_refc_valid( |
| struct xfs_refcount_irec *rc) |
| { |
| return rc->rc_startblock != NULLAGBLOCK; |
| } |
| |
| /* |
| * Try to merge with any extents on the boundaries of the adjustment range. |
| */ |
| STATIC int |
| xfs_refcount_merge_extents( |
| struct xfs_btree_cur *cur, |
| xfs_agblock_t *agbno, |
| xfs_extlen_t *aglen, |
| enum xfs_refc_adjust_op adjust, |
| int flags, |
| bool *shape_changed) |
| { |
| struct xfs_refcount_irec left = {0}, cleft = {0}; |
| struct xfs_refcount_irec cright = {0}, right = {0}; |
| int error; |
| unsigned long long 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, *agbno, |
| *aglen, flags); |
| if (error) |
| return error; |
| error = xfs_refcount_find_right_extents(cur, &right, &cright, *agbno, |
| *aglen, flags); |
| if (error) |
| return error; |
| |
| /* No left or right extent to merge; exit. */ |
| if (!xfs_refc_valid(&left) && !xfs_refc_valid(&right)) |
| return 0; |
| |
| cequal = (cleft.rc_startblock == cright.rc_startblock) && |
| (cleft.rc_blockcount == cright.rc_blockcount); |
| |
| /* Try to merge left, cleft, and right. cleft must == cright. */ |
| ulen = (unsigned long long)left.rc_blockcount + cleft.rc_blockcount + |
| right.rc_blockcount; |
| if (xfs_refc_valid(&left) && xfs_refc_valid(&right) && |
| xfs_refc_valid(&cleft) && xfs_refc_valid(&cright) && cequal && |
| left.rc_refcount == cleft.rc_refcount + adjust && |
| right.rc_refcount == cleft.rc_refcount + adjust && |
| ulen < MAXREFCEXTLEN) { |
| *shape_changed = true; |
| return xfs_refcount_merge_center_extents(cur, &left, &cleft, |
| &right, ulen, aglen); |
| } |
| |
| /* Try to merge left and cleft. */ |
| ulen = (unsigned long long)left.rc_blockcount + cleft.rc_blockcount; |
| if (xfs_refc_valid(&left) && xfs_refc_valid(&cleft) && |
| left.rc_refcount == cleft.rc_refcount + adjust && |
| ulen < MAXREFCEXTLEN) { |
| *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. */ |
| ulen = (unsigned long long)right.rc_blockcount + cright.rc_blockcount; |
| if (xfs_refc_valid(&right) && xfs_refc_valid(&cright) && |
| right.rc_refcount == cright.rc_refcount + adjust && |
| ulen < MAXREFCEXTLEN) { |
| *shape_changed = true; |
| return xfs_refcount_merge_right_extent(cur, &right, &cright, |
| aglen); |
| } |
| |
| return error; |
| } |
| |
| /* |
| * 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. |
| */ |
| static bool |
| xfs_refcount_still_have_space( |
| struct xfs_btree_cur *cur) |
| { |
| unsigned long overhead; |
| |
| overhead = cur->bc_private.a.priv.refc.shape_changes * |
| xfs_allocfree_log_count(cur->bc_mp, 1); |
| 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_private.a.priv.refc.nr_ops > 2 && |
| XFS_TEST_ERROR(false, cur->bc_mp, |
| XFS_ERRTAG_REFCOUNT_CONTINUE_UPDATE)) |
| return false; |
| |
| if (cur->bc_private.a.priv.refc.nr_ops == 0) |
| return true; |
| else if (overhead > cur->bc_tp->t_log_res) |
| return false; |
| return cur->bc_tp->t_log_res - overhead > |
| cur->bc_private.a.priv.refc.nr_ops * XFS_REFCOUNT_ITEM_OVERHEAD; |
| } |
| |
| /* |
| * 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]. |
| */ |
| STATIC int |
| 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_defer_ops *dfops, |
| struct xfs_owner_info *oinfo) |
| { |
| struct xfs_refcount_irec ext, tmp; |
| int error; |
| int found_rec, found_tmp; |
| xfs_fsblock_t fsbno; |
| |
| /* Merging did all the work already. */ |
| if (*aglen == 0) |
| return 0; |
| |
| error = xfs_refcount_lookup_ge(cur, *agbno, &found_rec); |
| if (error) |
| goto out_error; |
| |
| while (*aglen > 0 && xfs_refcount_still_have_space(cur)) { |
| error = xfs_refcount_get_rec(cur, &ext, &found_rec); |
| if (error) |
| goto out_error; |
| if (!found_rec) { |
| ext.rc_startblock = cur->bc_mp->m_sb.sb_agblocks; |
| ext.rc_blockcount = 0; |
| ext.rc_refcount = 0; |
| } |
| |
| /* |
| * 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; |
| trace_xfs_refcount_modify_extent(cur->bc_mp, |
| cur->bc_private.a.agno, &tmp); |
| |
| /* |
| * Either cover the hole (increment) or |
| * delete the range (decrement). |
| */ |
| if (tmp.rc_refcount) { |
| error = xfs_refcount_insert(cur, &tmp, |
| &found_tmp); |
| if (error) |
| goto out_error; |
| XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, |
| found_tmp == 1, out_error); |
| cur->bc_private.a.priv.refc.nr_ops++; |
| } else { |
| fsbno = XFS_AGB_TO_FSB(cur->bc_mp, |
| cur->bc_private.a.agno, |
| tmp.rc_startblock); |
| xfs_bmap_add_free(cur->bc_mp, dfops, fsbno, |
| tmp.rc_blockcount, oinfo); |
| } |
| |
| (*agbno) += tmp.rc_blockcount; |
| (*aglen) -= tmp.rc_blockcount; |
| |
| error = xfs_refcount_lookup_ge(cur, *agbno, |
| &found_rec); |
| if (error) |
| goto out_error; |
| } |
| |
| /* Stop if there's nothing left to modify */ |
| if (*aglen == 0 || !xfs_refcount_still_have_space(cur)) |
| break; |
| |
| /* |
| * Adjust the reference count and either update the tree |
| * (incr) or free the blocks (decr). |
| */ |
| if (ext.rc_refcount == MAXREFCOUNT) |
| goto skip; |
| ext.rc_refcount += adj; |
| trace_xfs_refcount_modify_extent(cur->bc_mp, |
| cur->bc_private.a.agno, &ext); |
| if (ext.rc_refcount > 1) { |
| error = xfs_refcount_update(cur, &ext); |
| if (error) |
| goto out_error; |
| cur->bc_private.a.priv.refc.nr_ops++; |
| } else if (ext.rc_refcount == 1) { |
| error = xfs_refcount_delete(cur, &found_rec); |
| if (error) |
| goto out_error; |
| XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, |
| found_rec == 1, out_error); |
| cur->bc_private.a.priv.refc.nr_ops++; |
| goto advloop; |
| } else { |
| fsbno = XFS_AGB_TO_FSB(cur->bc_mp, |
| cur->bc_private.a.agno, |
| ext.rc_startblock); |
| xfs_bmap_add_free(cur->bc_mp, dfops, fsbno, |
| ext.rc_blockcount, oinfo); |
| } |
| |
| skip: |
| error = xfs_btree_increment(cur, 0, &found_rec); |
| if (error) |
| goto out_error; |
| |
| advloop: |
| (*agbno) += ext.rc_blockcount; |
| (*aglen) -= ext.rc_blockcount; |
| } |
| |
| return error; |
| out_error: |
| trace_xfs_refcount_modify_extent_error(cur->bc_mp, |
| cur->bc_private.a.agno, error, _RET_IP_); |
| return error; |
| } |
| |
| /* Adjust the reference count of a range of AG blocks. */ |
| STATIC int |
| xfs_refcount_adjust( |
| struct xfs_btree_cur *cur, |
| xfs_agblock_t agbno, |
| xfs_extlen_t aglen, |
| xfs_agblock_t *new_agbno, |
| xfs_extlen_t *new_aglen, |
| enum xfs_refc_adjust_op adj, |
| struct xfs_defer_ops *dfops, |
| struct xfs_owner_info *oinfo) |
| { |
| bool shape_changed; |
| int shape_changes = 0; |
| int error; |
| |
| *new_agbno = agbno; |
| *new_aglen = aglen; |
| if (adj == XFS_REFCOUNT_ADJUST_INCREASE) |
| trace_xfs_refcount_increase(cur->bc_mp, cur->bc_private.a.agno, |
| agbno, aglen); |
| else |
| trace_xfs_refcount_decrease(cur->bc_mp, cur->bc_private.a.agno, |
| agbno, aglen); |
| |
| /* |
| * Ensure that no rcextents cross the boundary of the adjustment range. |
| */ |
| error = xfs_refcount_split_extent(cur, agbno, &shape_changed); |
| if (error) |
| goto out_error; |
| if (shape_changed) |
| shape_changes++; |
| |
| error = xfs_refcount_split_extent(cur, 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, new_agbno, new_aglen, adj, |
| XFS_FIND_RCEXT_SHARED, &shape_changed); |
| if (error) |
| goto out_error; |
| if (shape_changed) |
| shape_changes++; |
| if (shape_changes) |
| cur->bc_private.a.priv.refc.shape_changes++; |
| |
| /* Now that we've taken care of the ends, adjust the middle extents */ |
| error = xfs_refcount_adjust_extents(cur, new_agbno, new_aglen, |
| adj, dfops, oinfo); |
| if (error) |
| goto out_error; |
| |
| return 0; |
| |
| out_error: |
| trace_xfs_refcount_adjust_error(cur->bc_mp, cur->bc_private.a.agno, |
| error, _RET_IP_); |
| return error; |
| } |
| |
| /* Clean up after calling xfs_refcount_finish_one. */ |
| void |
| xfs_refcount_finish_one_cleanup( |
| struct xfs_trans *tp, |
| struct xfs_btree_cur *rcur, |
| int error) |
| { |
| struct xfs_buf *agbp; |
| |
| if (rcur == NULL) |
| return; |
| agbp = rcur->bc_private.a.agbp; |
| xfs_btree_del_cursor(rcur, error ? XFS_BTREE_ERROR : XFS_BTREE_NOERROR); |
| if (error) |
| xfs_trans_brelse(tp, agbp); |
| } |
| |
| /* |
| * 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_defer_ops *dfops, |
| enum xfs_refcount_intent_type type, |
| xfs_fsblock_t startblock, |
| xfs_extlen_t blockcount, |
| xfs_fsblock_t *new_fsb, |
| xfs_extlen_t *new_len, |
| struct xfs_btree_cur **pcur) |
| { |
| struct xfs_mount *mp = tp->t_mountp; |
| struct xfs_btree_cur *rcur; |
| struct xfs_buf *agbp = NULL; |
| int error = 0; |
| xfs_agnumber_t agno; |
| xfs_agblock_t bno; |
| xfs_agblock_t new_agbno; |
| unsigned long nr_ops = 0; |
| int shape_changes = 0; |
| |
| agno = XFS_FSB_TO_AGNO(mp, startblock); |
| ASSERT(agno != NULLAGNUMBER); |
| bno = XFS_FSB_TO_AGBNO(mp, startblock); |
| |
| trace_xfs_refcount_deferred(mp, XFS_FSB_TO_AGNO(mp, startblock), |
| type, XFS_FSB_TO_AGBNO(mp, startblock), |
| blockcount); |
| |
| 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. |
| */ |
| rcur = *pcur; |
| if (rcur != NULL && rcur->bc_private.a.agno != agno) { |
| nr_ops = rcur->bc_private.a.priv.refc.nr_ops; |
| shape_changes = rcur->bc_private.a.priv.refc.shape_changes; |
| xfs_refcount_finish_one_cleanup(tp, rcur, 0); |
| rcur = NULL; |
| *pcur = NULL; |
| } |
| if (rcur == NULL) { |
| error = xfs_alloc_read_agf(tp->t_mountp, tp, agno, |
| XFS_ALLOC_FLAG_FREEING, &agbp); |
| if (error) |
| return error; |
| if (!agbp) |
| return -EFSCORRUPTED; |
| |
| rcur = xfs_refcountbt_init_cursor(mp, tp, agbp, agno, dfops); |
| if (!rcur) { |
| error = -ENOMEM; |
| goto out_cur; |
| } |
| rcur->bc_private.a.priv.refc.nr_ops = nr_ops; |
| rcur->bc_private.a.priv.refc.shape_changes = shape_changes; |
| } |
| *pcur = rcur; |
| |
| switch (type) { |
| case XFS_REFCOUNT_INCREASE: |
| error = xfs_refcount_adjust(rcur, bno, blockcount, &new_agbno, |
| new_len, XFS_REFCOUNT_ADJUST_INCREASE, dfops, NULL); |
| *new_fsb = XFS_AGB_TO_FSB(mp, agno, new_agbno); |
| break; |
| case XFS_REFCOUNT_DECREASE: |
| error = xfs_refcount_adjust(rcur, bno, blockcount, &new_agbno, |
| new_len, XFS_REFCOUNT_ADJUST_DECREASE, dfops, NULL); |
| *new_fsb = XFS_AGB_TO_FSB(mp, agno, new_agbno); |
| break; |
| case XFS_REFCOUNT_ALLOC_COW: |
| *new_fsb = startblock + blockcount; |
| *new_len = 0; |
| error = __xfs_refcount_cow_alloc(rcur, bno, blockcount, dfops); |
| break; |
| case XFS_REFCOUNT_FREE_COW: |
| *new_fsb = startblock + blockcount; |
| *new_len = 0; |
| error = __xfs_refcount_cow_free(rcur, bno, blockcount, dfops); |
| break; |
| default: |
| ASSERT(0); |
| error = -EFSCORRUPTED; |
| } |
| if (!error && *new_len > 0) |
| trace_xfs_refcount_finish_one_leftover(mp, agno, type, |
| bno, blockcount, new_agbno, *new_len); |
| return error; |
| |
| out_cur: |
| xfs_trans_brelse(tp, agbp); |
| |
| return error; |
| } |
| |
| /* |
| * Record a refcount intent for later processing. |
| */ |
| static int |
| __xfs_refcount_add( |
| struct xfs_mount *mp, |
| struct xfs_defer_ops *dfops, |
| enum xfs_refcount_intent_type type, |
| xfs_fsblock_t startblock, |
| xfs_extlen_t blockcount) |
| { |
| struct xfs_refcount_intent *ri; |
| |
| trace_xfs_refcount_defer(mp, XFS_FSB_TO_AGNO(mp, startblock), |
| type, XFS_FSB_TO_AGBNO(mp, startblock), |
| blockcount); |
| |
| ri = kmem_alloc(sizeof(struct xfs_refcount_intent), |
| KM_SLEEP | KM_NOFS); |
| INIT_LIST_HEAD(&ri->ri_list); |
| ri->ri_type = type; |
| ri->ri_startblock = startblock; |
| ri->ri_blockcount = blockcount; |
| |
| xfs_defer_add(dfops, XFS_DEFER_OPS_TYPE_REFCOUNT, &ri->ri_list); |
| return 0; |
| } |
| |
| /* |
| * Increase the reference count of the blocks backing a file's extent. |
| */ |
| int |
| xfs_refcount_increase_extent( |
| struct xfs_mount *mp, |
| struct xfs_defer_ops *dfops, |
| struct xfs_bmbt_irec *PREV) |
| { |
| if (!xfs_sb_version_hasreflink(&mp->m_sb)) |
| return 0; |
| |
| return __xfs_refcount_add(mp, dfops, XFS_REFCOUNT_INCREASE, |
| PREV->br_startblock, PREV->br_blockcount); |
| } |
| |
| /* |
| * Decrease the reference count of the blocks backing a file's extent. |
| */ |
| int |
| xfs_refcount_decrease_extent( |
| struct xfs_mount *mp, |
| struct xfs_defer_ops *dfops, |
| struct xfs_bmbt_irec *PREV) |
| { |
| if (!xfs_sb_version_hasreflink(&mp->m_sb)) |
| return 0; |
| |
| return __xfs_refcount_add(mp, dfops, XFS_REFCOUNT_DECREASE, |
| PREV->br_startblock, PREV->br_blockcount); |
| } |
| |
| /* |
| * 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; |
| |
| trace_xfs_refcount_find_shared(cur->bc_mp, cur->bc_private.a.agno, |
| agbno, aglen); |
| |
| /* 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, 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; |
| XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, i == 1, out_error); |
| |
| /* 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; |
| XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, i == 1, out_error); |
| } |
| |
| /* 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; |
| } |
| |
| *fbno = tmp.rc_startblock; |
| *flen = min(tmp.rc_blockcount, agbno + aglen - *fbno); |
| if (!find_end_of_shared) |
| goto done; |
| |
| /* Otherwise, find the end of this shared extent */ |
| while (*fbno + *flen < agbno + aglen) { |
| error = xfs_btree_increment(cur, 0, &have); |
| if (error) |
| goto out_error; |
| if (!have) |
| break; |
| error = xfs_refcount_get_rec(cur, &tmp, &i); |
| if (error) |
| goto out_error; |
| XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, i == 1, out_error); |
| if (tmp.rc_startblock >= agbno + aglen || |
| tmp.rc_startblock != *fbno + *flen) |
| break; |
| *flen = min(*flen + tmp.rc_blockcount, agbno + aglen - *fbno); |
| } |
| |
| done: |
| trace_xfs_refcount_find_shared_result(cur->bc_mp, |
| cur->bc_private.a.agno, *fbno, *flen); |
| |
| out_error: |
| if (error) |
| trace_xfs_refcount_find_shared_error(cur->bc_mp, |
| cur->bc_private.a.agno, 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. |
| */ |
| STATIC int |
| 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, agbno, &found_rec); |
| if (error) |
| goto out_error; |
| error = xfs_refcount_get_rec(cur, &ext, &found_rec); |
| if (error) |
| goto out_error; |
| if (!found_rec) { |
| ext.rc_startblock = cur->bc_mp->m_sb.sb_agblocks + |
| XFS_REFC_COW_START; |
| ext.rc_blockcount = 0; |
| ext.rc_refcount = 0; |
| } |
| |
| switch (adj) { |
| case XFS_REFCOUNT_ADJUST_COW_ALLOC: |
| /* Adding a CoW reservation, there should be nothing here. */ |
| XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, |
| ext.rc_startblock >= agbno + aglen, out_error); |
| |
| tmp.rc_startblock = agbno; |
| tmp.rc_blockcount = aglen; |
| tmp.rc_refcount = 1; |
| trace_xfs_refcount_modify_extent(cur->bc_mp, |
| cur->bc_private.a.agno, &tmp); |
| |
| error = xfs_refcount_insert(cur, &tmp, |
| &found_tmp); |
| if (error) |
| goto out_error; |
| XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, |
| found_tmp == 1, out_error); |
| break; |
| case XFS_REFCOUNT_ADJUST_COW_FREE: |
| /* Removing a CoW reservation, there should be one extent. */ |
| XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, |
| ext.rc_startblock == agbno, out_error); |
| XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, |
| ext.rc_blockcount == aglen, out_error); |
| XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, |
| ext.rc_refcount == 1, out_error); |
| |
| ext.rc_refcount = 0; |
| trace_xfs_refcount_modify_extent(cur->bc_mp, |
| cur->bc_private.a.agno, &ext); |
| error = xfs_refcount_delete(cur, &found_rec); |
| if (error) |
| goto out_error; |
| XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, |
| found_rec == 1, out_error); |
| break; |
| default: |
| ASSERT(0); |
| } |
| |
| return error; |
| out_error: |
| trace_xfs_refcount_modify_extent_error(cur->bc_mp, |
| cur->bc_private.a.agno, error, _RET_IP_); |
| return error; |
| } |
| |
| /* |
| * Add or remove refcount btree entries for CoW reservations. |
| */ |
| STATIC int |
| 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; |
| |
| agbno += XFS_REFC_COW_START; |
| |
| /* |
| * Ensure that no rcextents cross the boundary of the adjustment range. |
| */ |
| error = xfs_refcount_split_extent(cur, agbno, &shape_changed); |
| if (error) |
| goto out_error; |
| |
| error = xfs_refcount_split_extent(cur, agbno + aglen, &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, &agbno, &aglen, adj, |
| XFS_FIND_RCEXT_COW, &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; |
| |
| return 0; |
| |
| out_error: |
| trace_xfs_refcount_adjust_cow_error(cur->bc_mp, cur->bc_private.a.agno, |
| error, _RET_IP_); |
| return error; |
| } |
| |
| /* |
| * Record a CoW allocation in the refcount btree. |
| */ |
| STATIC int |
| __xfs_refcount_cow_alloc( |
| struct xfs_btree_cur *rcur, |
| xfs_agblock_t agbno, |
| xfs_extlen_t aglen, |
| struct xfs_defer_ops *dfops) |
| { |
| trace_xfs_refcount_cow_increase(rcur->bc_mp, rcur->bc_private.a.agno, |
| agbno, aglen); |
| |
| /* Add refcount btree reservation */ |
| return xfs_refcount_adjust_cow(rcur, agbno, aglen, |
| XFS_REFCOUNT_ADJUST_COW_ALLOC); |
| } |
| |
| /* |
| * Remove a CoW allocation from the refcount btree. |
| */ |
| STATIC int |
| __xfs_refcount_cow_free( |
| struct xfs_btree_cur *rcur, |
| xfs_agblock_t agbno, |
| xfs_extlen_t aglen, |
| struct xfs_defer_ops *dfops) |
| { |
| trace_xfs_refcount_cow_decrease(rcur->bc_mp, rcur->bc_private.a.agno, |
| agbno, aglen); |
| |
| /* Remove refcount btree reservation */ |
| return xfs_refcount_adjust_cow(rcur, agbno, aglen, |
| XFS_REFCOUNT_ADJUST_COW_FREE); |
| } |
| |
| /* Record a CoW staging extent in the refcount btree. */ |
| int |
| xfs_refcount_alloc_cow_extent( |
| struct xfs_mount *mp, |
| struct xfs_defer_ops *dfops, |
| xfs_fsblock_t fsb, |
| xfs_extlen_t len) |
| { |
| int error; |
| |
| if (!xfs_sb_version_hasreflink(&mp->m_sb)) |
| return 0; |
| |
| error = __xfs_refcount_add(mp, dfops, XFS_REFCOUNT_ALLOC_COW, |
| fsb, len); |
| if (error) |
| return error; |
| |
| /* Add rmap entry */ |
| return xfs_rmap_alloc_extent(mp, dfops, XFS_FSB_TO_AGNO(mp, fsb), |
| XFS_FSB_TO_AGBNO(mp, fsb), len, XFS_RMAP_OWN_COW); |
| } |
| |
| /* Forget a CoW staging event in the refcount btree. */ |
| int |
| xfs_refcount_free_cow_extent( |
| struct xfs_mount *mp, |
| struct xfs_defer_ops *dfops, |
| xfs_fsblock_t fsb, |
| xfs_extlen_t len) |
| { |
| int error; |
| |
| if (!xfs_sb_version_hasreflink(&mp->m_sb)) |
| return 0; |
| |
| /* Remove rmap entry */ |
| error = xfs_rmap_free_extent(mp, dfops, XFS_FSB_TO_AGNO(mp, fsb), |
| XFS_FSB_TO_AGBNO(mp, fsb), len, XFS_RMAP_OWN_COW); |
| if (error) |
| return error; |
| |
| return __xfs_refcount_add(mp, dfops, XFS_REFCOUNT_FREE_COW, |
| fsb, len); |
| } |
| |
| struct xfs_refcount_recovery { |
| struct list_head rr_list; |
| struct xfs_refcount_irec rr_rrec; |
| }; |
| |
| /* Stuff an extent on the recovery list. */ |
| STATIC int |
| xfs_refcount_recover_extent( |
| struct xfs_btree_cur *cur, |
| union xfs_btree_rec *rec, |
| void *priv) |
| { |
| struct list_head *debris = priv; |
| struct xfs_refcount_recovery *rr; |
| |
| if (be32_to_cpu(rec->refc.rc_refcount) != 1) |
| return -EFSCORRUPTED; |
| |
| rr = kmem_alloc(sizeof(struct xfs_refcount_recovery), KM_SLEEP); |
| xfs_refcount_btrec_to_irec(rec, &rr->rr_rrec); |
| list_add_tail(&rr->rr_list, debris); |
| |
| return 0; |
| } |
| |
| /* Find and remove leftover CoW reservations. */ |
| int |
| xfs_refcount_recover_cow_leftovers( |
| struct xfs_mount *mp, |
| xfs_agnumber_t agno) |
| { |
| struct xfs_trans *tp; |
| struct xfs_btree_cur *cur; |
| struct xfs_buf *agbp; |
| struct xfs_refcount_recovery *rr, *n; |
| struct list_head debris; |
| union xfs_btree_irec low; |
| union xfs_btree_irec high; |
| struct xfs_defer_ops dfops; |
| xfs_fsblock_t fsb; |
| xfs_agblock_t agbno; |
| int error; |
| |
| if (mp->m_sb.sb_agblocks >= XFS_REFC_COW_START) |
| 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. |
| */ |
| error = xfs_trans_alloc_empty(mp, &tp); |
| if (error) |
| return error; |
| |
| error = xfs_alloc_read_agf(mp, tp, agno, 0, &agbp); |
| if (error) |
| goto out_trans; |
| if (!agbp) { |
| error = -ENOMEM; |
| goto out_trans; |
| } |
| cur = xfs_refcountbt_init_cursor(mp, tp, agbp, agno, NULL); |
| |
| /* Find all the leftover CoW staging extents. */ |
| memset(&low, 0, sizeof(low)); |
| memset(&high, 0, sizeof(high)); |
| low.rc.rc_startblock = XFS_REFC_COW_START; |
| high.rc.rc_startblock = -1U; |
| error = xfs_btree_query_range(cur, &low, &high, |
| xfs_refcount_recover_extent, &debris); |
| if (error) |
| goto out_cursor; |
| xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR); |
| xfs_trans_brelse(tp, agbp); |
| xfs_trans_cancel(tp); |
| |
| /* 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; |
| |
| trace_xfs_refcount_recover_extent(mp, agno, &rr->rr_rrec); |
| |
| /* Free the orphan record */ |
| xfs_defer_init(&dfops, &fsb); |
| agbno = rr->rr_rrec.rc_startblock - XFS_REFC_COW_START; |
| fsb = XFS_AGB_TO_FSB(mp, agno, agbno); |
| error = xfs_refcount_free_cow_extent(mp, &dfops, fsb, |
| rr->rr_rrec.rc_blockcount); |
| if (error) |
| goto out_defer; |
| |
| /* Free the block. */ |
| xfs_bmap_add_free(mp, &dfops, fsb, |
| rr->rr_rrec.rc_blockcount, NULL); |
| |
| error = xfs_defer_finish(&tp, &dfops); |
| if (error) |
| goto out_defer; |
| |
| error = xfs_trans_commit(tp); |
| if (error) |
| goto out_free; |
| |
| list_del(&rr->rr_list); |
| kmem_free(rr); |
| } |
| |
| return error; |
| out_defer: |
| xfs_defer_cancel(&dfops); |
| 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); |
| kmem_free(rr); |
| } |
| return error; |
| |
| out_cursor: |
| xfs_btree_del_cursor(cur, XFS_BTREE_ERROR); |
| xfs_trans_brelse(tp, agbp); |
| goto out_trans; |
| } |
| |
| /* Is there a record covering a given extent? */ |
| int |
| xfs_refcount_has_record( |
| struct xfs_btree_cur *cur, |
| xfs_agblock_t bno, |
| xfs_extlen_t len, |
| bool *exists) |
| { |
| union xfs_btree_irec low; |
| union xfs_btree_irec high; |
| |
| memset(&low, 0, sizeof(low)); |
| low.rc.rc_startblock = bno; |
| memset(&high, 0xFF, sizeof(high)); |
| high.rc.rc_startblock = bno + len - 1; |
| |
| return xfs_btree_has_record(cur, &low, &high, exists); |
| } |