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authorJan Kara <jack@suse.cz>2021-04-22 16:52:32 +0200
committerJan Kara <jack@suse.cz>2021-07-13 14:29:01 +0200
commitb092b3efc7cb239b6f33bb97da0f8812680e1046 (patch)
treed61a3007db3005aae514814d3d67721432418fda /fs/cifs
parent057ba5b24532aca202cb1ae8c246bde27de12763 (diff)
cifs: Fix race between hole punch and page fault
Cifs has a following race between hole punching and page fault: CPU1 CPU2 smb3_fallocate() smb3_punch_hole() truncate_pagecache_range() filemap_fault() - 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 <sfrench@samba.org> CC: linux-cifs@vger.kernel.org Signed-off-by: Jan Kara <jack@suse.cz>
Diffstat (limited to 'fs/cifs')
-rw-r--r--fs/cifs/smb2ops.c2
1 files changed, 2 insertions, 0 deletions
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);
free_xid(xid);
+ filemap_invalidate_unlock(inode->i_mapping);
return rc;
}