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 <sfre...@samba.org> CC: linux-c...@vger.kernel.org Signed-off-by: Jan Kara <j...@suse.cz> --- fs/cifs/smb2ops.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c index 21ef51d338e0..07c9ec047020 100644 --- a/fs/cifs/smb2ops.c +++ b/fs/cifs/smb2ops.c @@ -3581,6 +3581,7 @@ 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. @@ -3598,6 +3599,7 @@ 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; } -- 2.26.2 _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel