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Date:   Mon, 12 Jul 2021 18:56:05 +0200
From:   Jan Kara <>
To:     <>
Cc:     <>,
        Christoph Hellwig <>,
        "Darrick J. Wong" <>, Ted Tso <>,
        Dave Chinner <>,
        Matthew Wilcox <>, <>,
        <>,,,, Jan Kara <>,
        Steve French <>
Subject: [PATCH 14/14] cifs: Fix race between hole punch and page fault

Cifs has a following race between hole punching and page fault:

CPU1                                            CPU2
                                                  - loads old data into the
                                                    page cache
    SMB2_ioctl(..., FSCTL_SET_ZERO_DATA, ...)

And now we have stale data in the page cache. Fix the problem by locking
out faults (as well as reads) using mapping->invalidate_lock while hole
punch is running.

CC: Steve French <>
Signed-off-by: Jan Kara <>
 fs/cifs/smb2ops.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index e4c8f603dd58..458c546ce8cd 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -3588,6 +3588,7 @@ static long smb3_punch_hole(struct file *file, struct cifs_tcon *tcon,
 		return rc;
+	filemap_invalidate_lock(inode->i_mapping);
 	 * We implement the punch hole through ioctl, so we need remove the page
 	 * caches first, otherwise the data may be inconsistent with the server.
@@ -3605,6 +3606,7 @@ static long smb3_punch_hole(struct file *file, struct cifs_tcon *tcon,
 			sizeof(struct file_zero_data_information),
 			CIFSMaxBufSize, NULL, NULL);
+	filemap_invalidate_unlock(inode->i_mapping);
 	return rc;

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