[PATCH 3/7] btrfs: Use ihold instead of igrab in cow_file_range_async

Nikolay Borisov
2019-01-03T08:50:10Z

ihold is supposed to be used when the caller already has a reference to
the inode. In the case of cow_file_range_async this invariants holds,
since the 3 call chains leading to this function all take a reference:

btrfs_writepage <--- does igrab
extent_write_full_page
__extent_writepage
writepage_delalloc
btrfs_run_delalloc_range
cow_file_range_async

extent_write_cache_pages <--- does igrab
__extent_writepage (same callchain as above)

and

submit_compressed_extents <-- already called from async CoW submit path,
which would have done ihold.
extent_write_locked_range
__extent_writepage

No functional changes.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
---
fs/btrfs/inode.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 97ad494d0b3c..f023d2b5ef49 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -1194,7 +1194,8 @@ static int cow_file_range_async(struct inode *inode, struct page *locked_page,
async_cow = kmalloc(sizeof(*async_cow), GFP_NOFS);
if (!async_cow)
return -ENOMEM;
- async_cow->inode = igrab(inode);
+ ihold(inode);
+ async_cow->inode = inode;
async_cow->fs_info = fs_info;
async_cow->locked_page = locked_page;
async_cow->start = start;
--
2.17.1