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[4.4,06/20] cifs: revalidate mapping when we open files for SMB1 POSIX

Message ID 20210409095300.155554868@linuxfoundation.org
State New
Headers show
Series None | expand

Commit Message

Greg KH April 9, 2021, 9:53 a.m. UTC 
From: Ronnie Sahlberg <lsahlber@redhat.com>

[ Upstream commit cee8f4f6fcabfdf229542926128e9874d19016d5 ]

RHBZ: 1933527

Under SMB1 + POSIX, if an inode is reused on a server after we have read and
cached a part of a file, when we then open the new file with the
re-cycled inode there is a chance that we may serve the old data out of cache
to the application.
This only happens for SMB1 (deprecated) and when posix are used.
The simplest solution to avoid this race is to force a revalidate
on smb1-posix open.

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/cifs/file.c | 1 +
 1 file changed, 1 insertion(+)
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Patch

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index b5a05092f862..5bc617cb7721 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -163,6 +163,7 @@  int cifs_posix_open(char *full_path, struct inode **pinode,
 			goto posix_open_ret;
 		}
 	} else {
+		cifs_revalidate_mapping(*pinode);
 		cifs_fattr_to_inode(*pinode, &fattr);
 	}