diff options
-rw-r--r-- | fs/xfs/libxfs/xfs_refcount.c | 102 | ||||
-rw-r--r-- | fs/xfs/libxfs/xfs_refcount.h | 4 |
2 files changed, 106 insertions, 0 deletions
diff --git a/fs/xfs/libxfs/xfs_refcount.c b/fs/xfs/libxfs/xfs_refcount.c index 4a31a7c..ab8c30d 100644 --- a/fs/xfs/libxfs/xfs_refcount.c +++ b/fs/xfs/libxfs/xfs_refcount.c @@ -1163,3 +1163,105 @@ xfs_refcount_decrease_extent( 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; +} diff --git a/fs/xfs/libxfs/xfs_refcount.h b/fs/xfs/libxfs/xfs_refcount.h index 0a1f290..adba3ae 100644 --- a/fs/xfs/libxfs/xfs_refcount.h +++ b/fs/xfs/libxfs/xfs_refcount.h @@ -54,4 +54,8 @@ extern int xfs_refcount_finish_one(struct xfs_trans *tp, xfs_fsblock_t *new_fsb, xfs_extlen_t *new_len, struct xfs_btree_cur **pcur); +extern 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); + #endif /* __XFS_REFCOUNT_H__ */ |