Function unpin_extent_cache() currently never returns any error, even in
the event of an extent lookup failure. This commit fixes this by returning
-EINVAL when no extent is found. Additionally, it adds extra information
that may help debug any (hopefully) rare occasion when a lookup fails. The
only caller of this function is also modified to handle this error
condition.
Signed-off-by: Luís Henriques <[email protected]>
---
Changes since v2:
- As per Filipe's suggestion, provide as much debug info as possible.
This required modifying the function to get the inode instead of the
ext map tree.
- Since Filipe mentioned this WARN_ON() has been hit before, I guess it's
better to also handle this error in the caller instead of just continue.
But this is a change of the current behaviour and I may be wrong.
Changes since v1:
Instead of changing unpin_extent_cache() into a void function, make it
propagate an error code instead.
fs/btrfs/extent_map.c | 26 +++++++++++++++++++++-----
fs/btrfs/extent_map.h | 2 +-
fs/btrfs/inode.c | 8 +++++---
3 files changed, 27 insertions(+), 9 deletions(-)
diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index 0cdb3e86f29b..1a2e791cbfb4 100644
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -292,20 +292,37 @@ static void try_merge_map(struct extent_map_tree *tree, struct extent_map *em)
* to the generation that actually added the file item to the inode so we know
* we need to sync this extent when we call fsync().
*/
-int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len,
+int unpin_extent_cache(struct btrfs_inode *inode, u64 start, u64 len,
u64 gen)
{
int ret = 0;
+ struct extent_map_tree *tree = &inode->extent_tree;
struct extent_map *em;
bool prealloc = false;
write_lock(&tree->lock);
em = lookup_extent_mapping(tree, start, len);
- WARN_ON(!em || em->start != start);
+ if (!em || em->start != start) {
+ struct btrfs_fs_info *fs_info = inode->root->fs_info;
- if (!em)
- goto out;
+ if (!em)
+ btrfs_warn(fs_info,
+ "failed to find extent map");
+ else
+ btrfs_warn(fs_info,
+ "extent with wrong offset: start: %llu len: %llu flags: %lu",
+ em->start, em->len, em->flags);
+ btrfs_warn(fs_info,
+ "root %lld inode %llu offset %llu len: %llu",
+ inode->root->root_key.objectid, btrfs_ino(inode),
+ start, len);
+ WARN_ON(1);
+ if (!em) {
+ ret = -EINVAL;
+ goto out;
+ }
+ }
em->generation = gen;
clear_bit(EXTENT_FLAG_PINNED, &em->flags);
@@ -328,7 +345,6 @@ int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len,
out:
write_unlock(&tree->lock);
return ret;
-
}
void clear_em_logging(struct extent_map_tree *tree, struct extent_map *em)
diff --git a/fs/btrfs/extent_map.h b/fs/btrfs/extent_map.h
index 35d27c756e08..7a4ff55ee133 100644
--- a/fs/btrfs/extent_map.h
+++ b/fs/btrfs/extent_map.h
@@ -97,7 +97,7 @@ struct extent_map *alloc_extent_map(void);
void free_extent_map(struct extent_map *em);
int __init extent_map_init(void);
void __cold extent_map_exit(void);
-int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len, u64 gen);
+int unpin_extent_cache(struct btrfs_inode *inode, u64 start, u64 len, u64 gen);
void clear_em_logging(struct extent_map_tree *tree, struct extent_map *em);
struct extent_map *search_extent_mapping(struct extent_map_tree *tree,
u64 start, u64 len);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 49cef61f6a39..90efc2582f81 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -3181,7 +3181,7 @@ int btrfs_finish_one_ordered(struct btrfs_ordered_extent *ordered_extent)
struct extent_state *cached_state = NULL;
u64 start, end;
int compress_type = 0;
- int ret = 0;
+ int ret = 0, ret2;
u64 logical_len = ordered_extent->num_bytes;
bool freespace_inode;
bool truncated = false;
@@ -3273,8 +3273,10 @@ int btrfs_finish_one_ordered(struct btrfs_ordered_extent *ordered_extent)
ordered_extent->disk_num_bytes);
}
}
- unpin_extent_cache(&inode->extent_tree, ordered_extent->file_offset,
- ordered_extent->num_bytes, trans->transid);
+ ret2 = unpin_extent_cache(inode, ordered_extent->file_offset,
+ ordered_extent->num_bytes, trans->transid);
+ if (ret >= 0)
+ ret = ret2;
if (ret < 0) {
btrfs_abort_transaction(trans, ret);
goto out;