[PATCH 3.11 013/128] Btrfs: fix scrub_print_warning to handle skinny metadata extents

From: Luis Henriques
Date: Thu Jul 24 2014 - 06:25:32 EST


3.11.10.14 -stable review patch. If anyone has any objections, please let me know.

------------------

From: Liu Bo <bo.li.liu@xxxxxxxxxx>

commit 6eda71d0c030af0fc2f68aaa676e6d445600855b upstream.

The skinny extents are intepreted incorrectly in scrub_print_warning(),
and end up hitting the BUG() in btrfs_extent_inline_ref_size.

Reported-by: Konstantinos Skarlatos <k.skarlatos@xxxxxxxxx>
Signed-off-by: Liu Bo <bo.li.liu@xxxxxxxxxx>
Signed-off-by: Chris Mason <clm@xxxxxx>
Cc: David Sterba <dsterba@xxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
fs/btrfs/backref.c | 30 +++++++++++++++++++-----------
fs/btrfs/backref.h | 4 ++--
fs/btrfs/scrub.c | 5 +++--
3 files changed, 24 insertions(+), 15 deletions(-)

diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index 2b3d7ba4ad33..75b85578d98a 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -1369,9 +1369,10 @@ int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical,
* returns <0 on error
*/
static int __get_extent_inline_ref(unsigned long *ptr, struct extent_buffer *eb,
- struct btrfs_extent_item *ei, u32 item_size,
- struct btrfs_extent_inline_ref **out_eiref,
- int *out_type)
+ struct btrfs_key *key,
+ struct btrfs_extent_item *ei, u32 item_size,
+ struct btrfs_extent_inline_ref **out_eiref,
+ int *out_type)
{
unsigned long end;
u64 flags;
@@ -1381,9 +1382,16 @@ static int __get_extent_inline_ref(unsigned long *ptr, struct extent_buffer *eb,
/* first call */
flags = btrfs_extent_flags(eb, ei);
if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
- info = (struct btrfs_tree_block_info *)(ei + 1);
- *out_eiref =
- (struct btrfs_extent_inline_ref *)(info + 1);
+ if (key->type == BTRFS_METADATA_ITEM_KEY) {
+ /* a skinny metadata extent */
+ *out_eiref =
+ (struct btrfs_extent_inline_ref *)(ei + 1);
+ } else {
+ WARN_ON(key->type != BTRFS_EXTENT_ITEM_KEY);
+ info = (struct btrfs_tree_block_info *)(ei + 1);
+ *out_eiref =
+ (struct btrfs_extent_inline_ref *)(info + 1);
+ }
} else {
*out_eiref = (struct btrfs_extent_inline_ref *)(ei + 1);
}
@@ -1393,7 +1401,7 @@ static int __get_extent_inline_ref(unsigned long *ptr, struct extent_buffer *eb,
}

end = (unsigned long)ei + item_size;
- *out_eiref = (struct btrfs_extent_inline_ref *)*ptr;
+ *out_eiref = (struct btrfs_extent_inline_ref *)(*ptr);
*out_type = btrfs_extent_inline_ref_type(eb, *out_eiref);

*ptr += btrfs_extent_inline_ref_size(*out_type);
@@ -1412,8 +1420,8 @@ static int __get_extent_inline_ref(unsigned long *ptr, struct extent_buffer *eb,
* <0 on error.
*/
int tree_backref_for_extent(unsigned long *ptr, struct extent_buffer *eb,
- struct btrfs_extent_item *ei, u32 item_size,
- u64 *out_root, u8 *out_level)
+ struct btrfs_key *key, struct btrfs_extent_item *ei,
+ u32 item_size, u64 *out_root, u8 *out_level)
{
int ret;
int type;
@@ -1424,8 +1432,8 @@ int tree_backref_for_extent(unsigned long *ptr, struct extent_buffer *eb,
return 1;

while (1) {
- ret = __get_extent_inline_ref(ptr, eb, ei, item_size,
- &eiref, &type);
+ ret = __get_extent_inline_ref(ptr, eb, key, ei, item_size,
+ &eiref, &type);
if (ret < 0)
return ret;

diff --git a/fs/btrfs/backref.h b/fs/btrfs/backref.h
index 8f2e76702932..a3bd63b06044 100644
--- a/fs/btrfs/backref.h
+++ b/fs/btrfs/backref.h
@@ -40,8 +40,8 @@ int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical,
u64 *flags);

int tree_backref_for_extent(unsigned long *ptr, struct extent_buffer *eb,
- struct btrfs_extent_item *ei, u32 item_size,
- u64 *out_root, u8 *out_level);
+ struct btrfs_key *key, struct btrfs_extent_item *ei,
+ u32 item_size, u64 *out_root, u8 *out_level);

int iterate_extent_inodes(struct btrfs_fs_info *fs_info,
u64 extent_item_objectid,
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 64a157becbe5..8a56d4432522 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -545,8 +545,9 @@ static void scrub_print_warning(const char *errstr, struct scrub_block *sblock)

if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
do {
- ret = tree_backref_for_extent(&ptr, eb, ei, item_size,
- &ref_root, &ref_level);
+ ret = tree_backref_for_extent(&ptr, eb, &found_key, ei,
+ item_size, &ref_root,
+ &ref_level);
printk_in_rcu(KERN_WARNING
"btrfs: %s at logical %llu on dev %s, "
"sector %llu: metadata %s (level %d) in tree "
--
1.9.1

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