FAILED: patch "[PATCH] cifs/smb3: Fix data inconsistent when punch hole" failed to apply to 4.19-stable tree

PATCH [email protected] 2 participants 2 messages Jun 28, 2020 Stable branch

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[email protected]

author maintainer

2020-06-28 15:49 UTC #0 lore raw

The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From acc91c2d8de4ef46ed751c5f9df99ed9a109b100 Mon Sep 17 00:00:00 2001
From: Zhang Xiaoxu <[email protected]>
Date: Tue, 23 Jun 2020 07:31:53 -0400
Subject: [PATCH] cifs/smb3: Fix data inconsistent when punch hole

When punch hole success, we also can read old data from file:

  # strace -e trace=pread64,fallocate xfs_io -f -c "pread 20 40" \
           -c "fpunch 20 40" -c"pread 20 40" file
  pread64(3, " version 5.8.0-rc1+"..., 40, 20) = 40
  fallocate(3, FALLOC_FL_KEEP_SIZE|FALLOC_FL_PUNCH_HOLE, 20, 40) = 0
  pread64(3, " version 5.8.0-rc1+"..., 40, 20) = 40

CIFS implements the fallocate(FALLOCATE_FL_PUNCH_HOLE) with send SMB ioctl(FSCTL_SET_ZERO_DATA) to server. It just set the range of the remote file to zero, but local page caches not updated, then the local page caches inconsistent with server.

Also can be found by xfstests generic/316.

So, we need to remove the page caches before send the SMB ioctl(FSCTL_SET_ZERO_DATA) to server.

Fixes 31742c5a33176 ("enable fallocate punch hole ("fallocate -p") for SMB3")

Reviewed-by Pavel Shilovsky <[email protected]>

Signed-off-by Zhang Xiaoxu <[email protected]>

Cc [email protected] # v3.17

Signed-off-by Steve French <[email protected]>

fs/cifs/smb2ops.c +6 -0

index 876a0d9e3d46..d9fdafa5eb60 100644
@@ -3259,6 +3259,12 @@ static long smb3_punch_hole(struct file *file, struct cifs_tcon *tcon,
 		return rc;
 	}
 
+	/*
+	 * We implement the punch hole through ioctl, so we need remove the page
+	 * caches first, otherwise the data may be inconsistent with the server.
+	 */
+	truncate_pagecache_range(inode, offset, offset + len - 1);
+
 	cifs_dbg(FYI, "Offset %lld len %lld\n", offset, len);
 
 	fsctl_buf.FileOffset = cpu_to_le64(offset);

Sasha Levin

maintainer

2020-06-28 22:07 UTC #1 lore raw

Quoted 34 lines · On Sun, Jun 28, 2020 at 05:49:39PM +0200, [email protected] wrote:

The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From acc91c2d8de4ef46ed751c5f9df99ed9a109b100 Mon Sep 17 00:00:00 2001
From: Zhang Xiaoxu <[email protected]>
Date: Tue, 23 Jun 2020 07:31:53 -0400
Subject: [PATCH] cifs/smb3: Fix data inconsistent when punch hole
When punch hole success, we also can read old data from file:
 # strace -e trace=pread64,fallocate xfs_io -f -c "pread 20 40" \
          -c "fpunch 20 40" -c"pread 20 40" file
 pread64(3, " version 5.8.0-rc1+"..., 40, 20) = 40
 fallocate(3, FALLOC_FL_KEEP_SIZE|FALLOC_FL_PUNCH_HOLE, 20, 40) = 0
 pread64(3, " version 5.8.0-rc1+"..., 40, 20) = 40
CIFS implements the fallocate(FALLOCATE_FL_PUNCH_HOLE) with send SMB ioctl(FSCTL_SET_ZERO_DATA) to server. It just set the range of the remote file to zero, but local page caches not updated, then the local page caches inconsistent with server.
Also can be found by xfstests generic/316.
So, we need to remove the page caches before send the SMB ioctl(FSCTL_SET_ZERO_DATA) to server.

Quoted 6 lines

Fixes 31742c5a33176 ("enable fallocate punch hole ("fallocate -p") for SMB3")
Suggested-by Pavel Shilovsky <[email protected]>
Reviewed-by Pavel Shilovsky <[email protected]>
Signed-off-by Zhang Xiaoxu <[email protected]>
Cc [email protected] # v3.17
Signed-off-by Steve French <[email protected]>

Conflict with capitalization in the debug print. Fixed up and queued for 4.19, 4.14, 4.9, and 4.4.

Signature · 2 lines

Thanks,
Sasha