From f922cd90b82c5e78a860f194728d4dadc8575106 Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Wed, 3 Aug 2016 11:45:12 +1000 Subject: [PATCH] xfs: remove an extent from the rmap btree Originally-From: Dave Chinner Now that we have records in the rmap btree, we need to remove them when extents are freed. This needs to find the relevant record in the btree and remove/trim/split it accordingly. [darrick.wong@oracle.com: make rmap routines handle the enlarged keyspace] [dchinner: remove remaining unused debug printks] [darrick: fix a bug when growfs in an AG with an rmap ending at EOFS] Signed-off-by: Dave Chinner Signed-off-by: Darrick J. Wong Reviewed-by: Dave Chinner Reviewed-by: Brian Foster Signed-off-by: Dave Chinner --- fs/xfs/libxfs/xfs_rmap.c | 220 ++++++++++++++++++++++++++++++++++++++- 1 file changed, 215 insertions(+), 5 deletions(-) diff --git a/fs/xfs/libxfs/xfs_rmap.c b/fs/xfs/libxfs/xfs_rmap.c index 1c0e2a8943a4..1e48a0b62ba6 100644 --- a/fs/xfs/libxfs/xfs_rmap.c +++ b/fs/xfs/libxfs/xfs_rmap.c @@ -133,6 +133,212 @@ xfs_rmap_get_rec( return xfs_rmap_btrec_to_irec(rec, irec); } +/* + * Find the extent in the rmap btree and remove it. + * + * The record we find should always be an exact match for the extent that we're + * looking for, since we insert them into the btree without modification. + * + * Special Case #1: when growing the filesystem, we "free" an extent when + * growing the last AG. This extent is new space and so it is not tracked as + * used space in the btree. The growfs code will pass in an owner of + * XFS_RMAP_OWN_NULL to indicate that it expected that there is no owner of this + * extent. We verify that - the extent lookup result in a record that does not + * overlap. + * + * Special Case #2: EFIs do not record the owner of the extent, so when + * recovering EFIs from the log we pass in XFS_RMAP_OWN_UNKNOWN to tell the rmap + * btree to ignore the owner (i.e. wildcard match) so we don't trigger + * corruption checks during log recovery. + */ +STATIC int +xfs_rmap_unmap( + struct xfs_btree_cur *cur, + xfs_agblock_t bno, + xfs_extlen_t len, + bool unwritten, + struct xfs_owner_info *oinfo) +{ + struct xfs_mount *mp = cur->bc_mp; + struct xfs_rmap_irec ltrec; + uint64_t ltoff; + int error = 0; + int i; + uint64_t owner; + uint64_t offset; + unsigned int flags; + bool ignore_off; + + xfs_owner_info_unpack(oinfo, &owner, &offset, &flags); + ignore_off = XFS_RMAP_NON_INODE_OWNER(owner) || + (flags & XFS_RMAP_BMBT_BLOCK); + if (unwritten) + flags |= XFS_RMAP_UNWRITTEN; + trace_xfs_rmap_unmap(mp, cur->bc_private.a.agno, bno, len, + unwritten, oinfo); + + /* + * We should always have a left record because there's a static record + * for the AG headers at rm_startblock == 0 created by mkfs/growfs that + * will not ever be removed from the tree. + */ + error = xfs_rmap_lookup_le(cur, bno, len, owner, offset, flags, &i); + if (error) + goto out_error; + XFS_WANT_CORRUPTED_GOTO(mp, i == 1, out_error); + + error = xfs_rmap_get_rec(cur, <rec, &i); + if (error) + goto out_error; + XFS_WANT_CORRUPTED_GOTO(mp, i == 1, out_error); + trace_xfs_rmap_lookup_le_range_result(cur->bc_mp, + cur->bc_private.a.agno, ltrec.rm_startblock, + ltrec.rm_blockcount, ltrec.rm_owner, + ltrec.rm_offset, ltrec.rm_flags); + ltoff = ltrec.rm_offset; + + /* + * For growfs, the incoming extent must be beyond the left record we + * just found as it is new space and won't be used by anyone. This is + * just a corruption check as we don't actually do anything with this + * extent. Note that we need to use >= instead of > because it might + * be the case that the "left" extent goes all the way to EOFS. + */ + if (owner == XFS_RMAP_OWN_NULL) { + XFS_WANT_CORRUPTED_GOTO(mp, bno >= ltrec.rm_startblock + + ltrec.rm_blockcount, out_error); + goto out_done; + } + + /* Make sure the unwritten flag matches. */ + XFS_WANT_CORRUPTED_GOTO(mp, (flags & XFS_RMAP_UNWRITTEN) == + (ltrec.rm_flags & XFS_RMAP_UNWRITTEN), out_error); + + /* Make sure the extent we found covers the entire freeing range. */ + XFS_WANT_CORRUPTED_GOTO(mp, ltrec.rm_startblock <= bno && + ltrec.rm_startblock + ltrec.rm_blockcount >= + bno + len, out_error); + + /* Make sure the owner matches what we expect to find in the tree. */ + XFS_WANT_CORRUPTED_GOTO(mp, owner == ltrec.rm_owner || + XFS_RMAP_NON_INODE_OWNER(owner), out_error); + + /* Check the offset, if necessary. */ + if (!XFS_RMAP_NON_INODE_OWNER(owner)) { + if (flags & XFS_RMAP_BMBT_BLOCK) { + XFS_WANT_CORRUPTED_GOTO(mp, + ltrec.rm_flags & XFS_RMAP_BMBT_BLOCK, + out_error); + } else { + XFS_WANT_CORRUPTED_GOTO(mp, + ltrec.rm_offset <= offset, out_error); + XFS_WANT_CORRUPTED_GOTO(mp, + ltoff + ltrec.rm_blockcount >= offset + len, + out_error); + } + } + + if (ltrec.rm_startblock == bno && ltrec.rm_blockcount == len) { + /* exact match, simply remove the record from rmap tree */ + trace_xfs_rmap_delete(mp, cur->bc_private.a.agno, + ltrec.rm_startblock, ltrec.rm_blockcount, + ltrec.rm_owner, ltrec.rm_offset, + ltrec.rm_flags); + error = xfs_btree_delete(cur, &i); + if (error) + goto out_error; + XFS_WANT_CORRUPTED_GOTO(mp, i == 1, out_error); + } else if (ltrec.rm_startblock == bno) { + /* + * overlap left hand side of extent: move the start, trim the + * length and update the current record. + * + * ltbno ltlen + * Orig: |oooooooooooooooooooo| + * Freeing: |fffffffff| + * Result: |rrrrrrrrrr| + * bno len + */ + ltrec.rm_startblock += len; + ltrec.rm_blockcount -= len; + if (!ignore_off) + ltrec.rm_offset += len; + error = xfs_rmap_update(cur, <rec); + if (error) + goto out_error; + } else if (ltrec.rm_startblock + ltrec.rm_blockcount == bno + len) { + /* + * overlap right hand side of extent: trim the length and update + * the current record. + * + * ltbno ltlen + * Orig: |oooooooooooooooooooo| + * Freeing: |fffffffff| + * Result: |rrrrrrrrrr| + * bno len + */ + ltrec.rm_blockcount -= len; + error = xfs_rmap_update(cur, <rec); + if (error) + goto out_error; + } else { + + /* + * overlap middle of extent: trim the length of the existing + * record to the length of the new left-extent size, increment + * the insertion position so we can insert a new record + * containing the remaining right-extent space. + * + * ltbno ltlen + * Orig: |oooooooooooooooooooo| + * Freeing: |fffffffff| + * Result: |rrrrr| |rrrr| + * bno len + */ + xfs_extlen_t orig_len = ltrec.rm_blockcount; + + ltrec.rm_blockcount = bno - ltrec.rm_startblock; + error = xfs_rmap_update(cur, <rec); + if (error) + goto out_error; + + error = xfs_btree_increment(cur, 0, &i); + if (error) + goto out_error; + + cur->bc_rec.r.rm_startblock = bno + len; + cur->bc_rec.r.rm_blockcount = orig_len - len - + ltrec.rm_blockcount; + cur->bc_rec.r.rm_owner = ltrec.rm_owner; + if (ignore_off) + cur->bc_rec.r.rm_offset = 0; + else + cur->bc_rec.r.rm_offset = offset + len; + cur->bc_rec.r.rm_flags = flags; + trace_xfs_rmap_insert(mp, cur->bc_private.a.agno, + cur->bc_rec.r.rm_startblock, + cur->bc_rec.r.rm_blockcount, + cur->bc_rec.r.rm_owner, + cur->bc_rec.r.rm_offset, + cur->bc_rec.r.rm_flags); + error = xfs_btree_insert(cur, &i); + if (error) + goto out_error; + } + +out_done: + trace_xfs_rmap_unmap_done(mp, cur->bc_private.a.agno, bno, len, + unwritten, oinfo); +out_error: + if (error) + trace_xfs_rmap_unmap_error(mp, cur->bc_private.a.agno, + error, _RET_IP_); + return error; +} + +/* + * Remove a reference to an extent in the rmap btree. + */ int xfs_rmap_free( struct xfs_trans *tp, @@ -143,19 +349,23 @@ xfs_rmap_free( struct xfs_owner_info *oinfo) { struct xfs_mount *mp = tp->t_mountp; - int error = 0; + struct xfs_btree_cur *cur; + int error; if (!xfs_sb_version_hasrmapbt(&mp->m_sb)) return 0; - trace_xfs_rmap_unmap(mp, agno, bno, len, false, oinfo); - if (1) + cur = xfs_rmapbt_init_cursor(mp, tp, agbp, agno); + + error = xfs_rmap_unmap(cur, bno, len, false, oinfo); + if (error) goto out_error; - trace_xfs_rmap_unmap_done(mp, agno, bno, len, false, oinfo); + + xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR); return 0; out_error: - trace_xfs_rmap_unmap_error(mp, agno, error, _RET_IP_); + xfs_btree_del_cursor(cur, XFS_BTREE_ERROR); return error; } -- 2.20.1