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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,
	Goldwyn Rodrigues <rgoldwyn@suse.com>
Subject: [PATCH 10/10] btrfs: nowait aio support
Date: Thu, 11 May 2017 14:17:10 -0500
Message-ID: <20170511191710.31959-11-rgoldwyn@suse.de> (raw)
In-Reply-To: <20170511191710.31959-1-rgoldwyn@suse.de>

From: Goldwyn Rodrigues <rgoldwyn@suse.com>

Return EAGAIN if any of the following checks fail
 + i_rwsem is not lockable
 + NODATACOW or PREALLOC is not set
 + Cannot nocow at the desired location
 + Writing beyond end of file which is not allocated

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Acked-by: David Sterba <dsterba@suse.com>
---
 fs/btrfs/file.c  | 25 ++++++++++++++++++++-----
 fs/btrfs/inode.c |  3 +++
 2 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 520cb7230b2d..a870e5dd2b4d 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1823,12 +1823,29 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb,
 	ssize_t num_written = 0;
 	bool sync = (file->f_flags & O_DSYNC) || IS_SYNC(file->f_mapping->host);
 	ssize_t err;
-	loff_t pos;
-	size_t count;
+	loff_t pos = iocb->ki_pos;
+	size_t count = iov_iter_count(from);
 	loff_t oldsize;
 	int clean_page = 0;
 
-	inode_lock(inode);
+	if ((iocb->ki_flags & IOCB_NOWAIT) &&
+			(iocb->ki_flags & IOCB_DIRECT)) {
+		/* Don't sleep on inode rwsem */
+		if (!inode_trylock(inode))
+			return -EAGAIN;
+		/*
+		 * We will allocate space in case nodatacow is not set,
+		 * so bail
+		 */
+		if (!(BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW |
+					      BTRFS_INODE_PREALLOC)) ||
+		    check_can_nocow(BTRFS_I(inode), pos, &count) <= 0) {
+			inode_unlock(inode);
+			return -EAGAIN;
+		}
+	} else
+		inode_lock(inode);
+
 	err = generic_write_checks(iocb, from);
 	if (err <= 0) {
 		inode_unlock(inode);
@@ -1862,8 +1879,6 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb,
 	 */
 	update_time_for_write(inode);
 
-	pos = iocb->ki_pos;
-	count = iov_iter_count(from);
 	start_pos = round_down(pos, fs_info->sectorsize);
 	oldsize = i_size_read(inode);
 	if (start_pos > oldsize) {
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 5e71f1ea3391..47d3fcd86979 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -8625,6 +8625,9 @@ static ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 			dio_data.overwrite = 1;
 			inode_unlock(inode);
 			relock = true;
+		} else if (iocb->ki_flags & IOCB_NOWAIT) {
+			ret = -EAGAIN;
+			goto out;
 		}
 		ret = btrfs_delalloc_reserve_space(inode, offset, count);
 		if (ret)
-- 
2.12.0

  parent reply index

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-05-11 19:17 [PATCH 0/10 v8] No wait AIO Goldwyn Rodrigues
2017-05-11 19:17 ` [PATCH 01/10] fs: Separate out kiocb flags setup based on RWF_* flags Goldwyn Rodrigues
2017-05-11 19:17 ` [PATCH 02/10] fs: Introduce filemap_range_has_page() Goldwyn Rodrigues
     [not found] ` <20170511191710.31959-1-rgoldwyn-l3A5Bk7waGM@public.gmane.org>
2017-05-11 19:17   ` [PATCH 03/10] fs: Use RWF_* flags for AIO operations Goldwyn Rodrigues
2017-05-11 19:17 ` [PATCH 04/10] fs: Introduce RWF_NOWAIT Goldwyn Rodrigues
     [not found]   ` <20170511191710.31959-5-rgoldwyn-l3A5Bk7waGM@public.gmane.org>
2017-05-15  9:47     ` Jan Kara
2017-05-11 19:17 ` [PATCH 05/10] fs: return if direct write will trigger writeback Goldwyn Rodrigues
2017-05-11 19:17 ` [PATCH 06/10] fs: Introduce IOMAP_NOWAIT Goldwyn Rodrigues
2017-05-11 19:17 ` [PATCH 07/10] fs: return on congested block device Goldwyn Rodrigues
2017-05-11 19:17 ` [PATCH 08/10] ext4: nowait aio support Goldwyn Rodrigues
2017-05-11 19:17 ` [PATCH 09/10] xfs: " Goldwyn Rodrigues
2017-05-11 19:17 ` Goldwyn Rodrigues [this message]
2017-05-24 16:41 [PATCH 0/10 v9] No wait AIO Goldwyn Rodrigues
2017-05-24 16:41 ` [PATCH 10/10] btrfs: nowait aio support Goldwyn Rodrigues
2017-06-05  5:35 [PATCH 0/10 v10] No wait AIO Goldwyn Rodrigues
2017-06-05  5:35 ` [PATCH 10/10] btrfs: nowait aio support Goldwyn Rodrigues
2017-06-06 11:19 [PATCH 0/10 v11] No wait AIO Goldwyn Rodrigues
2017-06-06 11:19 ` [PATCH 10/10] btrfs: nowait aio support Goldwyn Rodrigues
2017-06-15 15:59 [PATCH 0/10 v12] No wait AIO Goldwyn Rodrigues
2017-06-15 16:00 ` [PATCH 10/10] btrfs: nowait aio support Goldwyn Rodrigues

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