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From: "Darrick J. Wong" <darrick.wong@oracle.com>
To: david@fromorbit.com, darrick.wong@oracle.com
Cc: linux-xfs@vger.kernel.org, xfs@oss.sgi.com
Subject: [PATCH 51/71] xfs: CoW shared EOF block when truncating file
Date: Thu, 25 Aug 2016 16:37:30 -0700	[thread overview]
Message-ID: <147216825024.867.15854938687374361206.stgit@birch.djwong.org> (raw)
In-Reply-To: <147216791538.867.12413509832420924168.stgit@birch.djwong.org>

When shrinking a file, the VFS zeroes everything in the associated
page between the new EOF and the previous EOF to avoid leaking data.
If this block is shared we need to CoW it before the VFS does its
zeroing to avoid corrupting the other files.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/xfs/xfs_iops.c    |    9 +++++++++
 fs/xfs/xfs_reflink.c |   42 ++++++++++++++++++++++++++++++++++++++++++
 fs/xfs/xfs_reflink.h |    1 +
 3 files changed, 52 insertions(+)


diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index b24c310..dc3f5ba5 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -39,6 +39,7 @@
 #include "xfs_trans_space.h"
 #include "xfs_pnfs.h"
 #include "xfs_iomap.h"
+#include "xfs_reflink.h"
 
 #include <linux/capability.h>
 #include <linux/xattr.h>
@@ -827,6 +828,14 @@ xfs_setattr_size(
 		return error;
 
 	/*
+	 * CoW the EOF block of the file if it's necessary to avoid
+	 * corrupting other files.
+	 */
+	error = xfs_reflink_cow_eof_block(ip, newsize);
+	if (error)
+		return error;
+
+	/*
 	 * We are going to log the inode size change in this transaction so
 	 * any previous writes that are beyond the on disk EOF and the new
 	 * EOF that have not been written out need to be written here.  If we
diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index d717e80..c0034c1 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -1701,3 +1701,45 @@ out:
 	trace_xfs_reflink_unshare_error(ip, error, _RET_IP_);
 	return error;
 }
+
+/*
+ * If we're trying to truncate a file whose last block is shared and the new
+ * size isn't aligned to a block boundary, we need to dirty that last block
+ * ahead of the VFS zeroing the page.
+ */
+int
+xfs_reflink_cow_eof_block(
+	struct xfs_inode	*ip,
+	xfs_off_t		newsize)
+{
+	struct xfs_mount	*mp = ip->i_mount;
+	xfs_fileoff_t		fbno;
+	xfs_off_t		isize;
+	int			error;
+
+	if (!xfs_is_reflink_inode(ip) ||
+	    (newsize & ((1 << VFS_I(ip)->i_blkbits) - 1)) == 0)
+		return 0;
+
+	/* Try to CoW the shared last block */
+	xfs_ilock(ip, XFS_ILOCK_EXCL);
+	fbno = XFS_B_TO_FSBT(mp, newsize);
+	isize = i_size_read(VFS_I(ip));
+
+	if (newsize > isize)
+		trace_xfs_reflink_cow_eof_block(ip, isize, newsize - isize);
+	else
+		trace_xfs_reflink_cow_eof_block(ip, newsize, isize - newsize);
+
+	error = xfs_reflink_dirty_extents(ip, fbno, fbno + 1, isize);
+	if (error)
+		goto out_unlock;
+	xfs_iunlock(ip, XFS_ILOCK_EXCL);
+
+	return 0;
+
+out_unlock:
+	xfs_iunlock(ip, XFS_ILOCK_EXCL);
+	trace_xfs_reflink_cow_eof_block_error(ip, error, _RET_IP_);
+	return error;
+}
diff --git a/fs/xfs/xfs_reflink.h b/fs/xfs/xfs_reflink.h
index 906c74d..89fe0e3 100644
--- a/fs/xfs/xfs_reflink.h
+++ b/fs/xfs/xfs_reflink.h
@@ -51,5 +51,6 @@ extern int xfs_reflink_remap_range(struct xfs_inode *src, xfs_off_t srcoff,
 		unsigned int flags);
 extern int xfs_reflink_unshare(struct xfs_inode *ip, xfs_off_t offset,
 		xfs_off_t len);
+extern int xfs_reflink_cow_eof_block(struct xfs_inode *ip, xfs_off_t newsize);
 
 #endif /* __XFS_REFLINK_H */

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  parent reply	other threads:[~2016-08-25 23:37 UTC|newest]

Thread overview: 119+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-25 23:31 [PATCH v8 00/71] xfs: add reflink and dedupe support Darrick J. Wong
2016-08-25 23:32 ` [PATCH 01/71] xfs: remove xfs_btree_bigkey Darrick J. Wong
2016-09-05 15:04   ` Christoph Hellwig
2016-08-25 23:32 ` [PATCH 02/71] xfs: create a standard btree size calculator code Darrick J. Wong
2016-09-05 15:05   ` Christoph Hellwig
2016-08-25 23:32 ` [PATCH 03/71] xfs: count the blocks in a btree Darrick J. Wong
2016-09-05 15:05   ` Christoph Hellwig
2016-08-25 23:32 ` [PATCH 04/71] xfs: defer should allow ->finish_item to request a new transaction Darrick J. Wong
2016-09-06  6:38   ` Christoph Hellwig
2016-09-06 23:57     ` Darrick J. Wong
2016-08-25 23:32 ` [PATCH 05/71] xfs: introduce tracepoints for AG reservation code Darrick J. Wong
2016-09-06  6:38   ` Christoph Hellwig
2016-08-25 23:32 ` [PATCH 06/71] xfs: set up per-AG free space reservations Darrick J. Wong
2016-09-06 14:53   ` Christoph Hellwig
2016-09-06 17:31     ` Darrick J. Wong
2016-09-08 17:47       ` Darrick J. Wong
2016-08-25 23:32 ` [PATCH 07/71] xfs: define tracepoints for refcount btree activities Darrick J. Wong
2016-09-06 14:54   ` Christoph Hellwig
2016-09-08 18:20     ` Darrick J. Wong
2016-08-25 23:32 ` [PATCH 08/71] xfs: introduce refcount btree definitions Darrick J. Wong
2016-09-06 14:59   ` Christoph Hellwig
2016-09-06 17:13     ` Darrick J. Wong
2016-08-25 23:32 ` [PATCH 09/71] xfs: add refcount btree stats infrastructure Darrick J. Wong
2016-09-06 14:59   ` Christoph Hellwig
2016-08-25 23:33 ` [PATCH 10/71] xfs: refcount btree add more reserved blocks Darrick J. Wong
2016-09-06 15:00   ` Christoph Hellwig
2016-08-25 23:33 ` [PATCH 11/71] xfs: define the on-disk refcount btree format Darrick J. Wong
2016-09-06 15:06   ` Christoph Hellwig
2016-08-25 23:33 ` [PATCH 12/71] xfs: add refcount btree support to growfs Darrick J. Wong
2016-09-06 15:06   ` Christoph Hellwig
2016-08-25 23:33 ` [PATCH 13/71] xfs: account for the refcount btree in the alloc/free log reservation Darrick J. Wong
2016-08-25 23:33 ` [PATCH 14/71] xfs: add refcount btree operations Darrick J. Wong
2016-09-06 15:09   ` Christoph Hellwig
2016-08-25 23:33 ` [PATCH 15/71] xfs: create refcount update intent log items Darrick J. Wong
2016-09-06 15:16   ` Christoph Hellwig
2016-09-06 16:43     ` Darrick J. Wong
2016-09-06 17:03       ` Christoph Hellwig
2016-08-25 23:33 ` [PATCH 16/71] xfs: log refcount intent items Darrick J. Wong
2016-09-06 15:21   ` Christoph Hellwig
2016-09-08 19:14     ` Darrick J. Wong
2016-09-08 23:13       ` Dave Chinner
2016-09-08 23:16         ` Darrick J. Wong
2016-09-11 12:52           ` Christoph Hellwig
2016-09-12 18:40             ` Darrick J. Wong
2016-09-12 23:28               ` Dave Chinner
2016-08-25 23:33 ` [PATCH 17/71] xfs: adjust refcount of an extent of blocks in refcount btree Darrick J. Wong
2016-08-25 23:33 ` [PATCH 18/71] xfs: connect refcount adjust functions to upper layers Darrick J. Wong
2016-08-25 23:34 ` [PATCH 19/71] xfs: adjust refcount when unmapping file blocks Darrick J. Wong
2016-08-25 23:34 ` [PATCH 20/71] xfs: add refcount btree block detection to log recovery Darrick J. Wong
2016-08-25 23:34 ` [PATCH 21/71] xfs: refcount btree requires more reserved space Darrick J. Wong
2016-08-25 23:34 ` [PATCH 22/71] xfs: introduce reflink utility functions Darrick J. Wong
2016-08-25 23:34 ` [PATCH 23/71] xfs: create bmbt update intent log items Darrick J. Wong
2016-08-25 23:34 ` [PATCH 24/71] xfs: log bmap intent items Darrick J. Wong
2016-08-25 23:34 ` [PATCH 25/71] xfs: map an inode's offset to an exact physical block Darrick J. Wong
2016-08-25 23:34 ` [PATCH 26/71] xfs: pass bmapi flags through to bmap_del_extent Darrick J. Wong
2016-08-25 23:34 ` [PATCH 27/71] xfs: implement deferred bmbt map/unmap operations Darrick J. Wong
2016-08-25 23:35 ` [PATCH 28/71] xfs: when replaying bmap operations, don't let unlinked inodes get reaped Darrick J. Wong
2016-08-25 23:35 ` [PATCH 29/71] xfs: return work remaining at the end of a bunmapi operation Darrick J. Wong
2016-08-25 23:35 ` [PATCH 30/71] xfs: define tracepoints for reflink activities Darrick J. Wong
2016-08-25 23:35 ` [PATCH 31/71] xfs: add reflink feature flag to geometry Darrick J. Wong
2016-08-25 23:35 ` [PATCH 32/71] xfs: don't allow reflinked dir/dev/fifo/socket/pipe files Darrick J. Wong
2016-08-25 23:35 ` [PATCH 33/71] xfs: introduce the CoW fork Darrick J. Wong
2016-08-25 23:35 ` [PATCH 34/71] xfs: support bmapping delalloc extents in " Darrick J. Wong
2016-09-06 15:25   ` Christoph Hellwig
2016-09-06 16:34     ` Darrick J. Wong
2016-09-11 12:59       ` Christoph Hellwig
2016-09-06 23:40     ` Dave Chinner
2016-09-11 12:57       ` Christoph Hellwig
2016-08-25 23:35 ` [PATCH 35/71] xfs: create delalloc extents in " Darrick J. Wong
2016-08-25 23:35 ` [PATCH 36/71] xfs: support allocating delayed " Darrick J. Wong
2016-08-25 23:35 ` [PATCH 37/71] xfs: allocate " Darrick J. Wong
2016-08-25 23:36 ` [PATCH 38/71] xfs: support removing extents from " Darrick J. Wong
2016-08-25 23:36 ` [PATCH 39/71] xfs: move mappings from cow fork to data fork after copy-write Darrick J. Wong
2016-08-25 23:36 ` [PATCH 40/71] xfs: report shared extents through the iomap interface Darrick J. Wong
2016-08-25 23:36 ` [PATCH 41/71] xfs: implement CoW for directio writes Darrick J. Wong
2016-08-25 23:36 ` [PATCH 42/71] xfs: cancel CoW reservations and clear inode reflink flag when freeing blocks Darrick J. Wong
2016-08-25 23:36 ` [PATCH 43/71] xfs: cancel pending CoW reservations when destroying inodes Darrick J. Wong
2016-08-25 23:36 ` [PATCH 44/71] xfs: store in-progress CoW allocations in the refcount btree Darrick J. Wong
2016-08-25 23:36 ` [PATCH 45/71] xfs: reflink extents from one file to another Darrick J. Wong
2016-08-25 23:36 ` [PATCH 46/71] xfs: add clone file and clone range vfs functions Darrick J. Wong
2016-08-25 23:37 ` [PATCH 47/71] xfs: add dedupe range vfs function Darrick J. Wong
2016-08-25 23:37 ` [PATCH 48/71] xfs: teach get_bmapx about shared extents and the CoW fork Darrick J. Wong
2016-08-25 23:37 ` [PATCH 49/71] xfs: swap inode reflink flags when swapping inode extents Darrick J. Wong
2016-08-25 23:37 ` [PATCH 50/71] xfs: unshare a range of blocks via fallocate Darrick J. Wong
2016-08-25 23:37 ` Darrick J. Wong [this message]
2016-08-25 23:37 ` [PATCH 52/71] xfs: support FS_XFLAG_REFLINK on reflink filesystems Darrick J. Wong
2016-08-25 23:37 ` [PATCH 53/71] xfs: create a separate cow extent size hint for the allocator Darrick J. Wong
2016-08-25 23:37 ` [PATCH 54/71] xfs: preallocate blocks for worst-case btree expansion Darrick J. Wong
2016-08-25 23:37 ` [PATCH 55/71] xfs: don't allow reflink when the AG is low on space Darrick J. Wong
2016-08-25 23:38 ` [PATCH 56/71] xfs: try other AGs to allocate a BMBT block Darrick J. Wong
2016-08-25 23:38 ` [PATCH 57/71] xfs: promote buffered writes to CoW when cowextsz is set Darrick J. Wong
2016-08-25 23:38 ` [PATCH 58/71] xfs: garbage collect old cowextsz reservations Darrick J. Wong
2016-09-24 19:42   ` Christoph Hellwig
2016-09-26 21:52     ` Darrick J. Wong
2016-09-27 18:50       ` Christoph Hellwig
2016-09-27 19:29         ` Darrick J. Wong
2016-09-27 20:15       ` Christoph Hellwig
2016-09-27 20:25         ` Darrick J. Wong
2016-08-25 23:38 ` [PATCH 59/71] xfs: provide switch to force filesystem to copy-on-write all the time Darrick J. Wong
2016-08-25 23:38 ` [PATCH 60/71] xfs: increase log reservations for reflink Darrick J. Wong
2016-08-25 23:38 ` [PATCH 61/71] xfs: add shared rmap map/unmap/convert log item types Darrick J. Wong
2016-08-25 23:38 ` [PATCH 62/71] xfs: use interval query for rmap alloc operations on shared files Darrick J. Wong
2016-08-25 23:38 ` [PATCH 63/71] xfs: convert unwritten status of reverse mappings for " Darrick J. Wong
2016-08-25 23:38 ` [PATCH 64/71] xfs: set a default CoW extent size of 32 blocks Darrick J. Wong
2016-08-25 23:38 ` [PATCH 65/71] xfs: check for invalid inode reflink flags Darrick J. Wong
2016-08-25 23:39 ` [PATCH 66/71] xfs: don't mix reflink and DAX mode for now Darrick J. Wong
2016-08-25 23:39 ` [PATCH 67/71] xfs: fail ->bmap for reflink inodes Darrick J. Wong
2016-09-06 15:29   ` Christoph Hellwig
2016-09-06 16:26     ` Darrick J. Wong
2016-09-06 17:02       ` Christoph Hellwig
2016-08-25 23:39 ` [PATCH 68/71] xfs: recognize the reflink feature bit Darrick J. Wong
2016-08-25 23:39 ` [PATCH 69/71] xfs: various swapext cleanups Darrick J. Wong
2016-08-25 23:39 ` [PATCH 70/71] xfs: refactor swapext code Darrick J. Wong
2016-08-25 23:39 ` [PATCH 71/71] xfs: implement swapext for rmap filesystems Darrick J. Wong
2016-08-26 12:56 ` [PATCH v8 00/71] xfs: add reflink and dedupe support Christoph Hellwig
2016-08-26 16:28   ` Darrick J. Wong
2016-08-26 18:42   ` Darrick J. Wong
2016-08-26 14:08 ` Brian Foster
2016-08-26 18:44 ` [PATCH 72/71] xfs: track log done items directly in the deferred pending work item Darrick J. Wong

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