From: Goldwyn Rodrigues <rgoldwyn@suse.de>
To: linux-fsdevel@vger.kernel.org
Cc: linux-btrfs@vger.kernel.org, david@fromorbit.com, hch@lst.de,
johannes.thumshirn@wdc.com, dsterba@suse.com,
darrick.wong@oracle.com, josef@toxicpanda.com,
Goldwyn Rodrigues <rgoldwyn@suse.com>
Subject: [PATCH 13/15] btrfs: Call iomap_dio_complete() without inode_lock
Date: Mon, 21 Sep 2020 09:43:51 -0500 [thread overview]
Message-ID: <20200921144353.31319-14-rgoldwyn@suse.de> (raw)
In-Reply-To: <20200921144353.31319-1-rgoldwyn@suse.de>
From: Goldwyn Rodrigues <rgoldwyn@suse.com>
If direct writes are called with O_DIRECT | O_DSYNC, it will result in a
deadlock because iomap_dio_rw() is called under i_rwsem which calls
iomap_dio_complete()
generic_write_sync()
btrfs_sync_file().
btrfs_sync_file() requires i_rwsem, so call __iomap_dio_rw() with the
i_rwsem locked, and call iomap_dio_complete() after unlocking i_rwsem.
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
---
fs/btrfs/file.c | 24 +++++++++++-------------
1 file changed, 11 insertions(+), 13 deletions(-)
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 193af84f5405..9c7a2d4b4148 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1981,6 +1981,7 @@ static ssize_t btrfs_direct_write(struct kiocb *iocb, struct iov_iter *from)
loff_t endbyte;
int err;
int ilock_flags = 0;
+ struct iomap_dio *dio = NULL;
if (iocb->ki_flags & IOCB_NOWAIT)
ilock_flags |= BTRFS_ILOCK_TRY;
@@ -2022,22 +2023,19 @@ static ssize_t btrfs_direct_write(struct kiocb *iocb, struct iov_iter *from)
goto buffered;
}
- /*
- * We have are actually a sync iocb, so we need our fancy endio to know
- * if we need to sync.
- */
- if (current->journal_info)
- written = iomap_dio_rw(iocb, from, &btrfs_dio_iomap_ops,
- &btrfs_sync_dops, is_sync_kiocb(iocb));
- else
- written = iomap_dio_rw(iocb, from, &btrfs_dio_iomap_ops,
- &btrfs_dio_ops, is_sync_kiocb(iocb));
-
- if (written == -ENOTBLK)
- written = 0;
+ dio = __iomap_dio_rw(iocb, from, &btrfs_dio_iomap_ops,
+ &btrfs_dio_ops, is_sync_kiocb(iocb));
btrfs_inode_unlock(inode, ilock_flags);
+ if (IS_ERR_OR_NULL(dio)) {
+ err = PTR_ERR_OR_ZERO(dio);
+ if (err < 0 && err != -ENOTBLK)
+ goto out;
+ } else {
+ written = iomap_dio_complete(dio);
+ }
+
if (written < 0 || !iov_iter_count(from)) {
err = written;
goto out;
--
2.26.2
next prev parent reply other threads:[~2020-09-21 14:44 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-21 14:43 [PATCH 0/15 v2] BTRFS DIO inode locking/D_SYNC fix Goldwyn Rodrigues
2020-09-21 14:43 ` [PATCH 01/15] fs: remove dio_end_io() Goldwyn Rodrigues
2020-09-22 14:17 ` Josef Bacik
2020-09-21 14:43 ` [PATCH 02/15] btrfs: remove BTRFS_INODE_READDIO_NEED_LOCK Goldwyn Rodrigues
2020-09-22 13:18 ` Christoph Hellwig
2020-09-22 14:17 ` Josef Bacik
2020-09-21 14:43 ` [PATCH 03/15] iomap: Allow filesystem to call iomap_dio_complete without i_rwsem Goldwyn Rodrigues
2020-09-21 15:09 ` Johannes Thumshirn
2020-09-22 13:19 ` hch
2020-09-22 14:17 ` Josef Bacik
2020-09-21 14:43 ` [PATCH 04/15] iomap: Call inode_dio_end() before generic_write_sync() Goldwyn Rodrigues
2020-09-21 15:11 ` Johannes Thumshirn
2020-09-22 13:21 ` Christoph Hellwig
2020-09-22 14:20 ` Josef Bacik
2020-09-22 16:31 ` Darrick J. Wong
2020-09-22 17:25 ` Goldwyn Rodrigues
2020-09-22 21:49 ` Dave Chinner
2020-09-23 5:16 ` Christoph Hellwig
2020-09-23 5:31 ` Darrick J. Wong
2020-09-23 5:49 ` Christoph Hellwig
2020-09-23 5:59 ` Dave Chinner
2020-09-21 14:43 ` [PATCH 05/15] btrfs: split btrfs_direct_IO to read and write Goldwyn Rodrigues
2020-09-22 13:22 ` Christoph Hellwig
2020-09-22 14:27 ` Josef Bacik
2020-09-21 14:43 ` [PATCH 06/15] btrfs: Move pos increment and pagecache extension to btrfs_buffered_write() Goldwyn Rodrigues
2020-09-22 13:22 ` Christoph Hellwig
2020-09-22 14:30 ` Josef Bacik
2020-09-21 14:43 ` [PATCH 07/15] btrfs: Move FS error state bit early during write Goldwyn Rodrigues
2020-09-22 14:38 ` Josef Bacik
2020-09-23 9:10 ` Nikolay Borisov
2020-09-23 14:07 ` Goldwyn Rodrigues
2020-09-21 14:43 ` [PATCH 08/15] btrfs: Introduce btrfs_write_check() Goldwyn Rodrigues
2020-09-22 13:26 ` Christoph Hellwig
2020-09-22 14:42 ` Josef Bacik
2020-09-21 14:43 ` [PATCH 09/15] btrfs: Introduce btrfs_inode_lock()/unlock() Goldwyn Rodrigues
2020-09-22 14:45 ` Josef Bacik
2020-09-21 14:43 ` [PATCH 10/15] btrfs: Push inode locking and unlocking into buffered/direct write Goldwyn Rodrigues
2020-09-22 14:48 ` Josef Bacik
2020-09-21 14:43 ` [PATCH 11/15] btrfs: Use inode_lock_shared() for direct writes within EOF Goldwyn Rodrigues
2020-09-22 14:52 ` Josef Bacik
2020-09-22 17:33 ` Goldwyn Rodrigues
2020-09-21 14:43 ` [PATCH 12/15] btrfs: Remove dio_sem Goldwyn Rodrigues
2020-09-22 14:52 ` Josef Bacik
2020-09-21 14:43 ` Goldwyn Rodrigues [this message]
2020-09-22 15:11 ` [PATCH 13/15] btrfs: Call iomap_dio_complete() without inode_lock Josef Bacik
2020-09-21 14:43 ` [PATCH 14/15] btrfs: Revert 09745ff88d93 ("btrfs: dio iomap DSYNC workaround") Goldwyn Rodrigues
2020-09-22 15:12 ` Josef Bacik
2020-09-21 14:43 ` [PATCH 15/15] iomap: Reinstate lockdep_assert_held in iomap_dio_rw() Goldwyn Rodrigues
2020-09-22 13:26 ` Christoph Hellwig
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