Patch "xfs: only reclaim unwritten COW extents periodically" has been added to the 4.9-stable tree

Patch "xfs: only reclaim unwritten COW extents periodically" has been added to the 4.9-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    xfs: only reclaim unwritten COW extents periodically

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     xfs-only-reclaim-unwritten-cow-extents-periodically.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 3802a345321a08093ba2ddb1849e736f84e8d450 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@lst.de>
Date: Tue, 7 Mar 2017 16:45:58 -0800
Subject: xfs: only reclaim unwritten COW extents periodically

From: Christoph Hellwig <hch@lst.de>

commit 3802a345321a08093ba2ddb1849e736f84e8d450 upstream.

We only want to reclaim preallocations from our periodic work item.
Currently this is archived by looking for a dirty inode, but that check
is rather fragile.  Instead add a flag to xfs_reflink_cancel_cow_* so
that the caller can ask for just cancelling unwritten extents in the COW
fork.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
[darrick: fix typos in commit message]
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/xfs/xfs_aops.c    |    2 +-
 fs/xfs/xfs_icache.c  |    2 +-
 fs/xfs/xfs_inode.c   |    2 +-
 fs/xfs/xfs_reflink.c |   23 ++++++++++++++++-------
 fs/xfs/xfs_reflink.h |    4 ++--
 fs/xfs/xfs_super.c   |    2 +-
 6 files changed, 22 insertions(+), 13 deletions(-)

--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -298,7 +298,7 @@ xfs_end_io(
 			goto done;
 		if (ioend->io_bio->bi_error) {
 			error = xfs_reflink_cancel_cow_range(ip,
-					ioend->io_offset, ioend->io_size);
+					ioend->io_offset, ioend->io_size, true);
 			goto done;
 		}
 		error = xfs_reflink_end_cow(ip, ioend->io_offset,
--- a/fs/xfs/xfs_icache.c
+++ b/fs/xfs/xfs_icache.c
@@ -1610,7 +1610,7 @@ xfs_inode_free_cowblocks(
 	xfs_ilock(ip, XFS_IOLOCK_EXCL);
 	xfs_ilock(ip, XFS_MMAPLOCK_EXCL);
 
-	ret = xfs_reflink_cancel_cow_range(ip, 0, NULLFILEOFF);
+	ret = xfs_reflink_cancel_cow_range(ip, 0, NULLFILEOFF, false);
 
 	xfs_iunlock(ip, XFS_MMAPLOCK_EXCL);
 	xfs_iunlock(ip, XFS_IOLOCK_EXCL);
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -1624,7 +1624,7 @@ xfs_itruncate_extents(
 
 	/* Remove all pending CoW reservations. */
 	error = xfs_reflink_cancel_cow_blocks(ip, &tp, first_unmap_block,
-			last_block);
+			last_block, true);
 	if (error)
 		goto out;
 
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -571,14 +571,18 @@ xfs_reflink_trim_irec_to_next_cow(
 }
 
 /*
- * Cancel all pending CoW reservations for some block range of an inode.
+ * Cancel CoW reservations for some block range of an inode.
+ *
+ * If cancel_real is true this function cancels all COW fork extents for the
+ * inode; if cancel_real is false, real extents are not cleared.
  */
 int
 xfs_reflink_cancel_cow_blocks(
 	struct xfs_inode		*ip,
 	struct xfs_trans		**tpp,
 	xfs_fileoff_t			offset_fsb,
-	xfs_fileoff_t			end_fsb)
+	xfs_fileoff_t			end_fsb,
+	bool				cancel_real)
 {
 	struct xfs_ifork		*ifp = XFS_IFORK_PTR(ip, XFS_COW_FORK);
 	struct xfs_bmbt_irec		got, prev, del;
@@ -605,7 +609,7 @@ xfs_reflink_cancel_cow_blocks(
 					&idx, &got, &del);
 			if (error)
 				break;
-		} else {
+		} else if (del.br_state == XFS_EXT_UNWRITTEN || cancel_real) {
 			xfs_trans_ijoin(*tpp, ip, 0);
 			xfs_defer_init(&dfops, &firstfsb);
 
@@ -648,13 +652,17 @@ xfs_reflink_cancel_cow_blocks(
 }
 
 /*
- * Cancel all pending CoW reservations for some byte range of an inode.
+ * Cancel CoW reservations for some byte range of an inode.
+ *
+ * If cancel_real is true this function cancels all COW fork extents for the
+ * inode; if cancel_real is false, real extents are not cleared.
  */
 int
 xfs_reflink_cancel_cow_range(
 	struct xfs_inode	*ip,
 	xfs_off_t		offset,
-	xfs_off_t		count)
+	xfs_off_t		count,
+	bool			cancel_real)
 {
 	struct xfs_trans	*tp;
 	xfs_fileoff_t		offset_fsb;
@@ -680,7 +688,8 @@ xfs_reflink_cancel_cow_range(
 	xfs_trans_ijoin(tp, ip, 0);
 
 	/* Scrape out the old CoW reservations */
-	error = xfs_reflink_cancel_cow_blocks(ip, &tp, offset_fsb, end_fsb);
+	error = xfs_reflink_cancel_cow_blocks(ip, &tp, offset_fsb, end_fsb,
+			cancel_real);
 	if (error)
 		goto out_cancel;
 
@@ -1686,7 +1695,7 @@ next:
 	 * We didn't find any shared blocks so turn off the reflink flag.
 	 * First, get rid of any leftover CoW mappings.
 	 */
-	error = xfs_reflink_cancel_cow_blocks(ip, tpp, 0, NULLFILEOFF);
+	error = xfs_reflink_cancel_cow_blocks(ip, tpp, 0, NULLFILEOFF, true);
 	if (error)
 		return error;
 
--- a/fs/xfs/xfs_reflink.h
+++ b/fs/xfs/xfs_reflink.h
@@ -39,9 +39,9 @@ extern int xfs_reflink_trim_irec_to_next
 
 extern int xfs_reflink_cancel_cow_blocks(struct xfs_inode *ip,
 		struct xfs_trans **tpp, xfs_fileoff_t offset_fsb,
-		xfs_fileoff_t end_fsb);
+		xfs_fileoff_t end_fsb, bool cancel_real);
 extern int xfs_reflink_cancel_cow_range(struct xfs_inode *ip, xfs_off_t offset,
-		xfs_off_t count);
+		xfs_off_t count, bool cancel_real);
 extern int xfs_reflink_end_cow(struct xfs_inode *ip, xfs_off_t offset,
 		xfs_off_t count);
 extern int xfs_reflink_recover_cow(struct xfs_mount *mp);
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -948,7 +948,7 @@ xfs_fs_destroy_inode(
 	XFS_STATS_INC(ip->i_mount, vn_remove);
 
 	if (xfs_is_reflink_inode(ip)) {
-		error = xfs_reflink_cancel_cow_range(ip, 0, NULLFILEOFF);
+		error = xfs_reflink_cancel_cow_range(ip, 0, NULLFILEOFF, true);
 		if (error && !XFS_FORCED_SHUTDOWN(ip->i_mount))
 			xfs_warn(ip->i_mount,
 "Error %d while evicting CoW blocks for inode %llu.",


Patches currently in stable-queue which might be from hch@lst.de are

queue-4.9/xfs-mark-speculative-prealloc-cow-fork-extents-unwritten.patch
queue-4.9/xfs-fix-toctou-race-when-locking-an-inode-to-access-the-data-map.patch
queue-4.9/xfs-use-iomap-new-flag-for-newly-allocated-delalloc-blocks.patch
queue-4.9/xfs-reject-all-unaligned-direct-writes-to-reflinked-files.patch
queue-4.9/xfs-allow-unwritten-extents-in-the-cow-fork.patch
queue-4.9/xfs-tune-down-agno-asserts-in-the-bmap-code.patch
queue-4.9/xfs-verify-free-block-header-fields.patch
queue-4.9/xfs-check-for-obviously-bad-level-values-in-the-bmbt-root.patch
queue-4.9/xfs-don-t-fail-xfs_extent_busy-allocation.patch
queue-4.9/xfs-sync-eofblocks-scans-under-iolock-are-livelock-prone.patch
queue-4.9/xfs-use-per-ag-reservations-for-the-finobt.patch
queue-4.9/xfs-pull-up-iolock-from-xfs_free_eofblocks.patch
queue-4.9/xfs-fail-_dir_open-when-readahead-fails.patch
queue-4.9/xfs-update-ctime-and-mtime-on-clone-destinatation-inodes.patch
queue-4.9/xfs-only-update-mount-resv-fields-on-success-in-__xfs_ag_resv_init.patch
queue-4.9/xfs-use-xfs_icluster_size_fsb-to-calculate-inode-chunk-alignment.patch
queue-4.9/xfs-only-reclaim-unwritten-cow-extents-periodically.patch
queue-4.9/xfs-try-any-ag-when-allocating-the-first-btree-block-when-reflinking.patch
queue-4.9/xfs-fix-and-streamline-error-handling-in-xfs_end_io.patch
queue-4.9/xfs-fix-eofblocks-race-with-file-extending-async-dio-writes.patch