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From: Goldwyn Rodrigues <rgoldwyn@suse.de>
To: linux-fsdevel@vger.kernel.org
Cc: jack@suse.com, hch@infradead.org, linux-block@vger.kernel.org,
	linux-btrfs@vger.kernel.org, linux-ext4@vger.kernel.org,
	linux-xfs@vger.kernel.org, sagi@grimberg.me, avi@scylladb.com,
	axboe@kernel.dk, linux-api@vger.kernel.org, willy@infradead.org,
	tom.leiming@gmail.com, Goldwyn Rodrigues <rgoldwyn@suse.com>
Subject: [PATCH 7/8] nowait aio: xfs
Date: Tue,  9 May 2017 07:22:18 -0500	[thread overview]
Message-ID: <20170509122219.31756-8-rgoldwyn@suse.de> (raw)
In-Reply-To: <20170509122219.31756-1-rgoldwyn@suse.de>

From: Goldwyn Rodrigues <rgoldwyn@suse.com>

If IOCB_NOWAIT is set, bail if the i_rwsem is not lockable
immediately.

IF IOMAP_NOWAIT is set, return EAGAIN in xfs_file_iomap_begin
if it needs allocation either due to file extension, writing to a hole,
or COW or waiting for other DIOs to finish.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 fs/xfs/xfs_file.c  | 19 ++++++++++++++-----
 fs/xfs/xfs_iomap.c | 17 +++++++++++++++++
 2 files changed, 31 insertions(+), 5 deletions(-)

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 35703a801372..b307940e7d56 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -541,8 +541,11 @@ xfs_file_dio_aio_write(
 		iolock = XFS_IOLOCK_SHARED;
 	}
 
-	xfs_ilock(ip, iolock);
-
+	if (!xfs_ilock_nowait(ip, iolock)) {
+		if (iocb->ki_flags & IOCB_NOWAIT)
+			return -EAGAIN;
+		xfs_ilock(ip, iolock);
+	}
 	ret = xfs_file_aio_write_checks(iocb, from, &iolock);
 	if (ret)
 		goto out;
@@ -553,9 +556,15 @@ xfs_file_dio_aio_write(
 	 * otherwise demote the lock if we had to take the exclusive lock
 	 * for other reasons in xfs_file_aio_write_checks.
 	 */
-	if (unaligned_io)
-		inode_dio_wait(inode);
-	else if (iolock == XFS_IOLOCK_EXCL) {
+	if (unaligned_io) {
+		/* If we are going to wait for other DIO to finish, bail */
+		if (iocb->ki_flags & IOCB_NOWAIT) {
+			if (atomic_read(&inode->i_dio_count))
+				return -EAGAIN;
+		} else {
+			inode_dio_wait(inode);
+		}
+	} else if (iolock == XFS_IOLOCK_EXCL) {
 		xfs_ilock_demote(ip, XFS_IOLOCK_EXCL);
 		iolock = XFS_IOLOCK_SHARED;
 	}
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 288ee5b840d7..9baa65eeae9e 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -1015,6 +1015,15 @@ xfs_file_iomap_begin(
 
 	if ((flags & (IOMAP_WRITE | IOMAP_ZERO)) && xfs_is_reflink_inode(ip)) {
 		if (flags & IOMAP_DIRECT) {
+			/*
+			 * A reflinked inode will result in CoW alloc.
+			 * FIXME: It could still overwrite on unshared extents
+			 * and not need allocation.
+			 */
+			if (flags & IOMAP_NOWAIT) {
+				error = -EAGAIN;
+				goto out_unlock;
+			}
 			/* may drop and re-acquire the ilock */
 			error = xfs_reflink_allocate_cow(ip, &imap, &shared,
 					&lockmode);
@@ -1032,6 +1041,14 @@ xfs_file_iomap_begin(
 
 	if ((flags & IOMAP_WRITE) && imap_needs_alloc(inode, &imap, nimaps)) {
 		/*
+		 * If nowait is set bail since we are going to make
+		 * allocations.
+		 */
+		if (flags & IOMAP_NOWAIT) {
+			error = -EAGAIN;
+			goto out_unlock;
+		}
+		/*
 		 * We cap the maximum length we map here to MAX_WRITEBACK_PAGES
 		 * pages to keep the chunks of work done where somewhat symmetric
 		 * with the work writeback does. This is a completely arbitrary
-- 
2.12.0


  parent reply	other threads:[~2017-05-09 12:22 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-05-09 12:22 [PATCH 0/8 v7] No wait AIO Goldwyn Rodrigues
2017-05-09 12:22 ` [PATCH 1/8] Use RWF_* flags for AIO operations Goldwyn Rodrigues
2017-05-11  7:40   ` Christoph Hellwig
2017-05-09 12:22 ` [PATCH 2/8] nowait aio: Introduce RWF_NOWAIT Goldwyn Rodrigues
2017-05-11  7:42   ` Christoph Hellwig
2017-05-09 12:22 ` [PATCH 3/8] nowait aio: return if direct write will trigger writeback Goldwyn Rodrigues
2017-05-11  7:42   ` Christoph Hellwig
2017-05-09 12:22 ` [PATCH 4/8] nowait-aio: Introduce IOMAP_NOWAIT Goldwyn Rodrigues
2017-05-09 12:22 ` [PATCH 5/8] nowait aio: return on congested block device Goldwyn Rodrigues
2017-05-11  7:44   ` Christoph Hellwig
     [not found]     ` <20170511074451.GD15626-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
2017-05-11 18:16       ` Goldwyn Rodrigues
2017-05-09 12:22 ` [PATCH 6/8] nowait aio: ext4 Goldwyn Rodrigues
     [not found]   ` <20170509122219.31756-7-rgoldwyn-l3A5Bk7waGM@public.gmane.org>
2017-05-09 14:57     ` Jan Kara
2017-05-09 12:22 ` Goldwyn Rodrigues [this message]
2017-05-11  7:45   ` [PATCH 7/8] nowait aio: xfs Christoph Hellwig
2017-05-09 12:22 ` [PATCH 8/8] nowait aio: btrfs Goldwyn Rodrigues
  -- strict thread matches above, loose matches on Subject: below --
2017-04-14 12:02 [PATCH 0/8 v6] No wait AIO Goldwyn Rodrigues
2017-04-14 12:02 ` [PATCH 7/8] nowait aio: xfs Goldwyn Rodrigues
2017-04-19  6:45   ` Christoph Hellwig
2017-04-03 18:52 [PATCH 0/8 v4] No wait AIO Goldwyn Rodrigues
2017-04-03 18:53 ` [PATCH 7/8] nowait aio: xfs Goldwyn Rodrigues
2017-04-04  6:52   ` Christoph Hellwig
     [not found]     ` <20170404065211.GD21942-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
2017-04-06 22:54       ` Darrick J. Wong
2017-04-07 11:34         ` Goldwyn Rodrigues
2017-04-07 15:08           ` Darrick J. Wong
2017-03-15 21:50 [PATCH 0/8 v3] No wait AIO Goldwyn Rodrigues
2017-03-15 21:51 ` [PATCH 7/8] nowait aio: xfs Goldwyn Rodrigues

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