[2/8] nowait aio: Return if cannot get hold of i_rwsem

Submitted by Goldwyn Rodrigues on April 3, 2017, 6:53 p.m.

Details

Message ID 20170403185307.6243-3-rgoldwyn@suse.de
State New
Headers show

Commit Message

Goldwyn Rodrigues April 3, 2017, 6:53 p.m.
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.

Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 mm/filemap.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

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diff --git a/mm/filemap.c b/mm/filemap.c
index 1694623..e08f3b9 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2982,7 +2982,12 @@  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);
+	if (!inode_trylock(inode)) {
+		/* Don't sleep on inode rwsem */
+		if (iocb->ki_flags & IOCB_NOWAIT)
+			return -EAGAIN;
+		inode_lock(inode);
+	}
 	ret = generic_write_checks(iocb, from);
 	if (ret > 0)
 		ret = __generic_file_write_iter(iocb, from);