From: Christoph Hellwig <hch@lst.de>
To: Goldwyn Rodrigues <rgoldwyn@suse.com>,
linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org
Cc: "Darrick J . Wong" <darrick.wong@oracle.com>
Subject: [PATCH 20/20] xfs: improve the IOMAP_NOWAIT check for COW inodes
Date: Tue, 8 Oct 2019 09:15:27 +0200 [thread overview]
Message-ID: <20191008071527.29304-21-hch@lst.de> (raw)
In-Reply-To: <20191008071527.29304-1-hch@lst.de>
Only bail out once we know that a COW allocation is actually required,
similar to how we handle normal data fork allocations.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
---
fs/xfs/xfs_iomap.c | 23 +++++------------------
1 file changed, 5 insertions(+), 18 deletions(-)
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index cc3d8fa011fc..46dee9c9e6ef 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -693,15 +693,8 @@ xfs_ilock_for_iomap(
* COW writes may allocate delalloc space or convert unwritten COW
* extents, so we need to make sure to take the lock exclusively here.
*/
- if (xfs_is_cow_inode(ip) && is_write) {
- /*
- * FIXME: It could still overwrite on unshared extents and not
- * need allocation.
- */
- if (flags & IOMAP_NOWAIT)
- return -EAGAIN;
+ if (xfs_is_cow_inode(ip) && is_write)
mode = XFS_ILOCK_EXCL;
- }
/*
* Extents not yet cached requires exclusive access, don't block. This
@@ -760,12 +753,6 @@ xfs_direct_write_iomap_begin(
if (XFS_FORCED_SHUTDOWN(mp))
return -EIO;
- /*
- * Lock the inode in the manner required for the specified operation and
- * check for as many conditions that would result in blocking as
- * possible. This removes most of the non-blocking checks from the
- * mapping code below.
- */
error = xfs_ilock_for_iomap(ip, flags, &lockmode);
if (error)
return error;
@@ -775,11 +762,11 @@ xfs_direct_write_iomap_begin(
if (error)
goto out_unlock;
- /*
- * Break shared extents if necessary. Checks for non-blocking IO have
- * been done up front, so we don't need to do them here.
- */
if (imap_needs_cow(ip, flags, &imap, nimaps)) {
+ error = -EAGAIN;
+ if (flags & IOMAP_NOWAIT)
+ goto out_unlock;
+
/* may drop and re-acquire the ilock */
error = xfs_reflink_allocate_cow(ip, &imap, &cmap, &shared,
&lockmode, flags & IOMAP_DIRECT);
--
2.20.1
prev parent reply other threads:[~2019-10-08 7:16 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-08 7:15 iomap and xfs COW cleanups v2 Christoph Hellwig
2019-10-08 7:15 ` [PATCH 01/20] iomap: better document the IOMAP_F_* flags Christoph Hellwig
2019-10-08 7:15 ` [PATCH 02/20] iomap: remove the unused iomap argument to __iomap_write_end Christoph Hellwig
2019-10-08 7:15 ` [PATCH 03/20] iomap: always use AOP_FLAG_NOFS in iomap_write_begin Christoph Hellwig
2019-10-08 7:15 ` [PATCH 04/20] iomap: ignore non-shared or non-data blocks in xfs_file_dirty Christoph Hellwig
2019-10-08 7:15 ` [PATCH 05/20] iomap: move the zeroing case out of iomap_read_page_sync Christoph Hellwig
2019-10-08 7:15 ` [PATCH 06/20] iomap: use write_begin to read pages to unshare Christoph Hellwig
2019-10-08 15:12 ` Darrick J. Wong
2019-10-08 7:15 ` [PATCH 07/20] iomap: renumber IOMAP_HOLE to 0 Christoph Hellwig
2019-10-08 15:01 ` Darrick J. Wong
2019-10-08 7:15 ` [PATCH 08/20] iomap: use a srcmap for a read-modify-write I/O Christoph Hellwig
2019-10-08 15:00 ` Darrick J. Wong
2019-10-09 6:28 ` Christoph Hellwig
2019-10-09 17:16 ` Darrick J. Wong
2019-10-14 23:27 ` Darrick J. Wong
2019-10-15 13:00 ` Goldwyn Rodrigues
2019-10-08 7:15 ` [PATCH 09/20] xfs: also call xfs_file_iomap_end_delalloc for zeroing operations Christoph Hellwig
2019-10-08 7:15 ` [PATCH 10/20] xfs: remove xfs_reflink_dirty_extents Christoph Hellwig
2019-10-08 15:20 ` Darrick J. Wong
2019-10-08 7:15 ` [PATCH 11/20] xfs: pass two imaps to xfs_reflink_allocate_cow Christoph Hellwig
2019-10-08 7:15 ` [PATCH 12/20] xfs: refactor xfs_file_iomap_begin_delay Christoph Hellwig
2019-10-08 7:15 ` [PATCH 13/20] xfs: fill out the srcmap in iomap_begin Christoph Hellwig
2019-10-08 15:26 ` Darrick J. Wong
2019-10-08 7:15 ` [PATCH 14/20] xfs: factor out a helper to calculate the end_fsb Christoph Hellwig
2019-10-08 7:15 ` [PATCH 15/20] xfs: split out a new set of read-only iomap ops Christoph Hellwig
2019-10-08 15:27 ` Darrick J. Wong
2019-10-08 7:15 ` [PATCH 16/20] xfs: move xfs_file_iomap_begin_delay around Christoph Hellwig
2019-10-08 7:15 ` [PATCH 17/20] xfs: split the iomap ops for buffered vs direct writes Christoph Hellwig
2019-10-08 15:28 ` Darrick J. Wong
2019-10-08 7:15 ` [PATCH 18/20] xfs: rename the whichfork variable in xfs_buffered_write_iomap_begin Christoph Hellwig
2019-10-08 7:15 ` [PATCH 19/20] xfs: cleanup xfs_iomap_write_unwritten Christoph Hellwig
2019-10-08 7:15 ` Christoph Hellwig [this message]
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