diff mbox

[2/7] noblocking aio: Return if cannot get hold of i_rwsem

Message ID 20170214024603.9563-3-rgoldwyn@suse.de (mailing list archive)
State New, archived
Headers show

Commit Message

Goldwyn Rodrigues Feb. 14, 2017, 2:45 a.m. UTC 
From: Goldwyn Rodrigues <rgoldwyn@suse.com>

A failure to lock i_rwsem would mean there is I/O being performed
by another thread. So, let's bail.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
---
 mm/filemap.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

Comments

Christoph Hellwig Feb. 20, 2017, 9:24 a.m. UTC | #1 
> +	/* Don't sleep on inode rwsem */
> +	if (iocb->ki_flags & IOCB_NONBLOCKING) {
> +		if (!inode_trylock(inode))
> +			return -EAGAIN;
> +	} else
> +		inode_lock(inode);

A way to avoid the additional branch in the fast path would be:

	if (!inode_trylock(inode)) {
		if (iocb->ki_flags & IOCB_NONBLOCKING)
			return -EAGAIN;
		inode_lock(inode);
	}

but otherwise this looks fine:

Reviewed-by: Christoph Hellwig <hch@lst.de>
diff mbox

Patch

diff --git a/mm/filemap.c b/mm/filemap.c
index d8d7df8..50cee70 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2885,7 +2885,12 @@  ssize_t generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	struct inode *inode = file->f_mapping->host;
 	ssize_t ret;
 
-	inode_lock(inode);
+	/* Don't sleep on inode rwsem */
+	if (iocb->ki_flags & IOCB_NONBLOCKING) {
+		if (!inode_trylock(inode))
+			return -EAGAIN;
+	} else
+		inode_lock(inode);
 	ret = generic_write_checks(iocb, from);
 	if (ret > 0)
 		ret = __generic_file_write_iter(iocb, from);