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From: Matthew Bobrowski <mbobrowski@mbobrowski.org>
To: tytso@mit.edu, jack@suse.cz, adilger.kernel@dilger.ca
Cc: linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	hch@infradead.org, david@fromorbit.com, darrick.wong@oracle.com
Subject: [PATCH v6 02/11] ext4: update direct I/O read lock pattern for IOCB_NOWAIT
Date: Mon, 28 Oct 2019 21:50:54 +1100	[thread overview]
Message-ID: <17824b863511c87c3b4ea36531ca3c1430d30660.1572255425.git.mbobrowski@mbobrowski.org> (raw)
In-Reply-To: <cover.1572255424.git.mbobrowski@mbobrowski.org>

This patch updates the lock pattern in ext4_direct_IO_read() to not
block on inode lock in cases of IOCB_NOWAIT direct I/O reads. The
locking condition implemented here is similar to that of 942491c9e6d6
("xfs: fix AIM7 regression").

Fixes: 16c54688592c ("ext4: Allow parallel DIO reads")
Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com>
---
 fs/ext4/inode.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index ee116344c420..0a9ea291cfab 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3837,7 +3837,13 @@ static ssize_t ext4_direct_IO_read(struct kiocb *iocb, struct iov_iter *iter)
 	 * writes & truncates and since we take care of writing back page cache,
 	 * we are protected against page writeback as well.
 	 */
-	inode_lock_shared(inode);
+	if (iocb->ki_flags & IOCB_NOWAIT) {
+		if (!inode_trylock_shared(inode))
+			return -EAGAIN;
+	} else {
+		inode_lock_shared(inode);
+	}
+
 	ret = filemap_write_and_wait_range(mapping, iocb->ki_pos,
 					   iocb->ki_pos + count - 1);
 	if (ret)
-- 
2.20.1


  parent reply	other threads:[~2019-10-28 10:51 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-28 10:50 [PATCH v6 00/11] ext4: port direct I/O to iomap infrastructure Matthew Bobrowski
2019-10-28 10:50 ` [PATCH v6 01/11] ext4: reorder map.m_flags checks within ext4_iomap_begin() Matthew Bobrowski
2019-10-28 10:50 ` Matthew Bobrowski [this message]
2019-10-28 10:51 ` [PATCH v6 03/11] ext4: iomap that extends beyond EOF should be marked dirty Matthew Bobrowski
2019-10-28 10:51 ` [PATCH v6 04/11] ext4: move set iomap routines into a separate helper ext4_set_iomap() Matthew Bobrowski
2019-10-28 17:03   ` Darrick J. Wong
2019-10-28 20:36     ` Matthew Bobrowski
2019-10-28 23:56       ` Darrick J. Wong
2019-10-28 10:51 ` [PATCH v6 05/11] ext4: split IOMAP_WRITE branch in ext4_iomap_begin() into helper Matthew Bobrowski
2019-10-28 10:52 ` [PATCH v6 06/11] ext4: introduce new callback for IOMAP_REPORT Matthew Bobrowski
2019-10-29  5:42   ` Ritesh Harjani
2019-10-28 10:52 ` [PATCH v6 07/11] ext4: introduce direct I/O read using iomap infrastructure Matthew Bobrowski
2019-10-28 10:52 ` [PATCH v6 08/11] ext4: move inode extension/truncate code out from ->iomap_end() callback Matthew Bobrowski
2019-10-29  5:46   ` Ritesh Harjani
2019-10-28 10:53 ` [PATCH v6 09/11] ext4: move inode extension check out from ext4_iomap_alloc() Matthew Bobrowski
2019-10-28 10:53 ` [PATCH v6 11/11] ext4: introduce direct I/O write using iomap infrastructure Matthew Bobrowski
2019-10-29  6:14   ` Ritesh Harjani
2019-10-28 10:53 ` [PATCH v6 10/11] ext4: update ext4_sync_file() to not use __generic_file_fsync() Matthew Bobrowski
2019-10-29  6:12   ` Ritesh Harjani
2019-10-30 11:18   ` Jan Kara
2019-10-29 23:31 ` [PATCH v6 00/11] ext4: port direct I/O to iomap infrastructure Theodore Y. Ts'o
2019-10-29 23:34   ` Theodore Y. Ts'o
2019-10-30  2:00     ` Matthew Bobrowski
2019-10-30 11:26       ` Jan Kara
2019-10-30 11:39         ` Jan Kara
2019-10-31  9:16           ` Matthew Bobrowski
2019-10-31 16:54             ` Jan Kara
2019-10-31 22:58               ` Matthew Bobrowski
2019-11-03 19:20 ` Theodore Y. Ts'o
2019-11-04  6:04   ` Matthew Bobrowski

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