diff options
| author | Filipe Manana <fdmanana@suse.com> | 2022-03-23 16:19:29 +0000 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2022-05-16 17:03:10 +0200 |
| commit | 4f208dcc6bf572fbe8178cfea703f139803863ba (patch) | |
| tree | 58c998fbdae0f6dbef738d201c2d86c37b99bf1a | |
| parent | 59d35c5171e65f3a208b6f44d028278f129bdeab (diff) | |
btrfs: avoid blocking when allocating context for nowait dio read/write
When doing a NOWAIT direct IO read/write, we allocate a context object
(struct btrfs_dio_data) with GFP_NOFS, which can result in blocking
waiting for memory allocation (GFP_NOFS is __GFP_RECLAIM | __GFP_IO).
This is undesirable for the NOWAIT semantics, so do the allocation with
GFP_NOWAIT if we are serving a NOWAIT request and if the allocation fails
return -EAGAIN, so that the caller can fallback to a blocking context and
retry with a non-blocking write.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
| -rw-r--r-- | fs/btrfs/inode.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 1922c7004bf5..4254c3c7b9f7 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -7588,9 +7588,15 @@ static int btrfs_dio_iomap_begin(struct inode *inode, loff_t start, } } - dio_data = kzalloc(sizeof(*dio_data), GFP_NOFS); - if (!dio_data) - return -ENOMEM; + if (flags & IOMAP_NOWAIT) { + dio_data = kzalloc(sizeof(*dio_data), GFP_NOWAIT); + if (!dio_data) + return -EAGAIN; + } else { + dio_data = kzalloc(sizeof(*dio_data), GFP_NOFS); + if (!dio_data) + return -ENOMEM; + } iomap->private = dio_data; |