| Message ID | 20180228101323.25442-2-lufq.fnst@cn.fujitsu.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 2018年02月28日 18:13, Lu Fengqi wrote: > Btrfs lowmem check reports the following false alert: > ------ > ERROR: file extent[267 2162688] root 256 owner 5 backref lost > ------ > > The file extent is in the leaf which is shared by file tree 256 and fs > tree. > ------ > leaf 30605312 items 46 free space 4353 generation 7 owner 5 > ...... > item 45 key (267 EXTENT_DATA 2162688) itemoff 5503 itemsize 53 > generation 7 type 2 (prealloc) > prealloc data disk byte 13631488 nr 65536 > prealloc data offset 32768 nr 32768 > ------ > > And there is the corresponding extent_data_ref item in the extent tree. > ------ > item 1 key (13631488 EXTENT_DATA_REF 1007496934287921081) itemoff 15274 itemsize 28 > extent data backref root 5 objectid 267 offset 2129920 count 1 > ------ > > The offset of EXTENT_DATA_REF which is the hash of the owner root objectid, > the inode number and the calculated offset (file offset - extent offset). > > What caused the false alert is the code mix up the owner root objectid and > the file tree objectid. > > Fixes: b0d360b541f0 ("btrfs-progs: check: introduce function to check data backref in extent tree") > Signed-off-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com> Looks good. Reviewed-by: Qu Wenruo <wqu@suse.com> Thanks, Qu > --- > check/mode-lowmem.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/check/mode-lowmem.c b/check/mode-lowmem.c > index f37b1b2c1571..6f1ea8db341d 100644 > --- a/check/mode-lowmem.c > +++ b/check/mode-lowmem.c > @@ -2689,8 +2689,8 @@ static int check_extent_data_item(struct btrfs_root *root, > /* Didn't find inlined data backref, try EXTENT_DATA_REF_KEY */ > dbref_key.objectid = btrfs_file_extent_disk_bytenr(eb, fi); > dbref_key.type = BTRFS_EXTENT_DATA_REF_KEY; > - dbref_key.offset = hash_extent_data_ref(root->objectid, > - fi_key.objectid, fi_key.offset - offset); > + dbref_key.offset = hash_extent_data_ref(owner, fi_key.objectid, > + fi_key.offset - offset); > > ret = btrfs_search_slot(NULL, root->fs_info->extent_root, > &dbref_key, &path, 0, 0); >
diff --git a/check/mode-lowmem.c b/check/mode-lowmem.c index f37b1b2c1571..6f1ea8db341d 100644 --- a/check/mode-lowmem.c +++ b/check/mode-lowmem.c @@ -2689,8 +2689,8 @@ static int check_extent_data_item(struct btrfs_root *root, /* Didn't find inlined data backref, try EXTENT_DATA_REF_KEY */ dbref_key.objectid = btrfs_file_extent_disk_bytenr(eb, fi); dbref_key.type = BTRFS_EXTENT_DATA_REF_KEY; - dbref_key.offset = hash_extent_data_ref(root->objectid, - fi_key.objectid, fi_key.offset - offset); + dbref_key.offset = hash_extent_data_ref(owner, fi_key.objectid, + fi_key.offset - offset); ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &dbref_key, &path, 0, 0);
Btrfs lowmem check reports the following false alert: ------ ERROR: file extent[267 2162688] root 256 owner 5 backref lost ------ The file extent is in the leaf which is shared by file tree 256 and fs tree. ------ leaf 30605312 items 46 free space 4353 generation 7 owner 5 ...... item 45 key (267 EXTENT_DATA 2162688) itemoff 5503 itemsize 53 generation 7 type 2 (prealloc) prealloc data disk byte 13631488 nr 65536 prealloc data offset 32768 nr 32768 ------ And there is the corresponding extent_data_ref item in the extent tree. ------ item 1 key (13631488 EXTENT_DATA_REF 1007496934287921081) itemoff 15274 itemsize 28 extent data backref root 5 objectid 267 offset 2129920 count 1 ------ The offset of EXTENT_DATA_REF which is the hash of the owner root objectid, the inode number and the calculated offset (file offset - extent offset). What caused the false alert is the code mix up the owner root objectid and the file tree objectid. Fixes: b0d360b541f0 ("btrfs-progs: check: introduce function to check data backref in extent tree") Signed-off-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com> --- check/mode-lowmem.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)