In submit_extent_page, there's a visually noisy if statement that, in
the midst of other conditions, does the tree dependency for tree->ops
and tree->ops->merge_bio_hook before calling it, and then another
condition afterwards. If an error is returned from merge_bio_hook,
there's no way to catch it. It's considered a routine "1" return
value instead of a failure.
This patch factors out the dependency check into a new local merge_bio
routine and BUG's on an error. The if statement is less noisy as a side-
effect.
Signed-off-by: Jeff Mahoney <je...@suse.com>
---
fs/btrfs/extent_io.c | 17 ++++++++++++++---
fs/btrfs/inode.c | 5 +++--
2 files changed, 17 insertions(+), 5 deletions(-)
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 0575792..09095b8 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2058,6 +2058,19 @@ static int submit_one_bio(int rw, struct bio *bio, int
mirror_num,
return ret;
}
+static int merge_bio(struct extent_io_tree *tree, struct page *page,
+ unsigned long offset, size_t size, struct bio *bio,
+ unsigned long bio_flags)
+{
+ int ret = 0;
+ if (tree->ops && tree->ops->merge_bio_hook)
+ ret = tree->ops->merge_bio_hook(page, offset, size, bio,
+ bio_flags);
+ BUG_ON(ret < 0);
+ return ret;
+
+}
+
static int submit_extent_page(int rw, struct extent_io_tree *tree,
struct page *page, sector_t sector,
size_t size, unsigned long offset,
@@ -2086,9 +2099,7 @@ static int submit_extent_page(int rw, struct
extent_io_tree *tree,
sector;
if (prev_bio_flags != bio_flags || !contig ||
- (tree->ops && tree->ops->merge_bio_hook &&
- tree->ops->merge_bio_hook(page, offset, page_size, bio,
- bio_flags)) ||
+ merge_bio(tree, page, offset, page_size, bio, bio_flags) ||
bio_add_page(bio, page, page_size, offset) < page_size) {
ret = submit_one_bio(rw, bio, mirror_num,
prev_bio_flags);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index c0dc599..a06cb64 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -1425,10 +1425,11 @@ int btrfs_merge_bio_hook(struct page *page, unsigned
long offset,
map_length = length;
ret = btrfs_map_block(map_tree, READ, logical,
&map_length, NULL, 0);
-
+ /* Will always return 0 or 1 with map_multi == NULL */
+ BUG_ON(ret < 0);
if (map_length < length + size)
return 1;
- return ret;
+ return 0;
}
/*
--
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