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btrfs: Factor out tree->ops->merge_bio_hook call

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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 <jeffm@suse.com>
This commit is contained in:
Jeff Mahoney 2011-10-03 23:23:13 -04:00 committed by David Sterba
parent 0417341e6b
commit 3444a97255
2 changed files with 17 additions and 5 deletions
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17
fs/btrfs/extent_io.c
View File

@ -2429,6 +2429,19 @@ 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,
@ -2457,9 +2470,7 @@ 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);

5
fs/btrfs/inode.c
View File

@ -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;
}
/*