From 8ca15e05e6ac2745725d2d62394cfbe4ac335e84 Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Fri, 5 Jul 2013 13:58:19 -0400 Subject: Btrfs: fix backref walking when we hit a compressed extent If you do btrfs inspect-internal logical-resolve on a compressed extent that has been partly overwritten it won't find anything. This is because we try and match the extent offset we've searched for based on the extent offset in the data extent entry. However this doesn't work for compressed extents because the offsets are for the uncompressed size, not the compressed size. So instead only do this check if we are not compressed, that way we can get an actual entry for the physical offset rather than nothing for compressed. Thanks, Signed-off-by: Josef Bacik Signed-off-by: Chris Mason --- fs/btrfs/backref.c | 23 +++++++++++++++-------- 1 file changed, 15 insertions(+), 8 deletions(-) (limited to 'fs/btrfs/backref.c') diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c index eaf133384a8..30dbe1c6185 100644 --- a/fs/btrfs/backref.c +++ b/fs/btrfs/backref.c @@ -36,16 +36,23 @@ static int check_extent_in_eb(struct btrfs_key *key, struct extent_buffer *eb, u64 extent_item_pos, struct extent_inode_elem **eie) { - u64 data_offset; - u64 data_len; + u64 offset = 0; struct extent_inode_elem *e; - data_offset = btrfs_file_extent_offset(eb, fi); - data_len = btrfs_file_extent_num_bytes(eb, fi); + if (!btrfs_file_extent_compression(eb, fi) && + !btrfs_file_extent_encryption(eb, fi) && + !btrfs_file_extent_other_encoding(eb, fi)) { + u64 data_offset; + u64 data_len; - if (extent_item_pos < data_offset || - extent_item_pos >= data_offset + data_len) - return 1; + data_offset = btrfs_file_extent_offset(eb, fi); + data_len = btrfs_file_extent_num_bytes(eb, fi); + + if (extent_item_pos < data_offset || + extent_item_pos >= data_offset + data_len) + return 1; + offset = extent_item_pos - data_offset; + } e = kmalloc(sizeof(*e), GFP_NOFS); if (!e) @@ -53,7 +60,7 @@ static int check_extent_in_eb(struct btrfs_key *key, struct extent_buffer *eb, e->next = *eie; e->inum = key->objectid; - e->offset = key->offset + (extent_item_pos - data_offset); + e->offset = key->offset + offset; *eie = e; return 0; -- cgit v1.2.3-70-g09d2 From ed8c4913da4951957bf8afc788522788881ff405 Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Fri, 5 Jul 2013 14:03:47 -0400 Subject: Btrfs: make sure the backref walker catches all refs to our extent Because we don't mess with the offset into the extent for compressed we will properly find both extents for this case [extent a][extent b][rest of extent a] but because we already added a ref for the front half we won't add the inode information for the second half. This causes us to leak that memory and not print out the other offset when we do logical-resolve. So fix this by calling ulist_add_merge and then add our eie to the existing entry if there is one. With this patch we get both offsets out of logical-resolve. With this and the other 2 patches I've sent we now pass btrfs/276 on my vm with compress-force=lzo set. Thanks, Signed-off-by: Josef Bacik Signed-off-by: Chris Mason --- fs/btrfs/backref.c | 25 ++++++++++++++----------- 1 file changed, 14 insertions(+), 11 deletions(-) (limited to 'fs/btrfs/backref.c') diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c index 30dbe1c6185..8bc5e8ccb09 100644 --- a/fs/btrfs/backref.c +++ b/fs/btrfs/backref.c @@ -196,7 +196,7 @@ static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path, struct extent_buffer *eb; struct btrfs_key key; struct btrfs_file_extent_item *fi; - struct extent_inode_elem *eie = NULL; + struct extent_inode_elem *eie = NULL, *old = NULL; u64 disk_byte; if (level != 0) { @@ -230,6 +230,7 @@ static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path, if (disk_byte == wanted_disk_byte) { eie = NULL; + old = NULL; if (extent_item_pos) { ret = check_extent_in_eb(&key, eb, fi, *extent_item_pos, @@ -237,18 +238,20 @@ static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path, if (ret < 0) break; } - if (!ret) { - ret = ulist_add(parents, eb->start, - (uintptr_t)eie, GFP_NOFS); - if (ret < 0) - break; - if (!extent_item_pos) { - ret = btrfs_next_old_leaf(root, path, - time_seq); - continue; - } + if (ret > 0) + goto next; + ret = ulist_add_merge(parents, eb->start, + (uintptr_t)eie, + (u64 *)&old, GFP_NOFS); + if (ret < 0) + break; + if (!ret && extent_item_pos) { + while (old->next) + old = old->next; + old->next = eie; } } +next: ret = btrfs_next_old_item(root, path, time_seq); } -- cgit v1.2.3-70-g09d2