[PATCH 4.19 149/190] cifs: Properly handle auto disabling of serverino option

Greg Kroah-Hartman
2019-09-13T13:30:00Z

[ Upstream commit 29fbeb7a908a60a5ae8c50fbe171cb8fdcef1980 ]

Fix mount options comparison when serverino option is turned off later
in cifs_autodisable_serverino() and thus avoiding mismatch of new cifs
mounts.

Cc: stable@vger.kernel.org
Signed-off-by: Paulo Alcantara (SUSE) <paulo@paulo.ac>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilove@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/cifs/cifs_fs_sb.h | 5 +++++
fs/cifs/connect.c | 8 ++++++--
fs/cifs/misc.c | 1 +
3 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/fs/cifs/cifs_fs_sb.h b/fs/cifs/cifs_fs_sb.h
index 9731d0d891e7e..aba2b48d4da1a 100644
--- a/fs/cifs/cifs_fs_sb.h
+++ b/fs/cifs/cifs_fs_sb.h
@@ -72,5 +72,10 @@ struct cifs_sb_info {
struct delayed_work prune_tlinks;
struct rcu_head rcu;
char *prepath;
+ /*
+ * Indicate whether serverino option was turned off later
+ * (cifs_autodisable_serverino) in order to match new mounts.
+ */
+ bool mnt_cifs_serverino_autodisabled;
};
#endif /* _CIFS_FS_SB_H */
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index c53a2e86ed544..208430bb66fc6 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -3247,12 +3247,16 @@ compare_mount_options(struct super_block *sb, struct cifs_mnt_data *mnt_data)
{
struct cifs_sb_info *old = CIFS_SB(sb);
struct cifs_sb_info *new = mnt_data->cifs_sb;
+ unsigned int oldflags = old->mnt_cifs_flags & CIFS_MOUNT_MASK;
+ unsigned int newflags = new->mnt_cifs_flags & CIFS_MOUNT_MASK;

if ((sb->s_flags & CIFS_MS_MASK) != (mnt_data->flags & CIFS_MS_MASK))
return 0;

- if ((old->mnt_cifs_flags & CIFS_MOUNT_MASK) !=
- (new->mnt_cifs_flags & CIFS_MOUNT_MASK))
+ if (old->mnt_cifs_serverino_autodisabled)
+ newflags &= ~CIFS_MOUNT_SERVER_INUM;
+
+ if (oldflags != newflags)
return 0;

/*
diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
index facc94e159a16..e45f8e321371c 100644
--- a/fs/cifs/misc.c
+++ b/fs/cifs/misc.c
@@ -523,6 +523,7 @@ cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb)
{
if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
+ cifs_sb->mnt_cifs_serverino_autodisabled = true;
cifs_dbg(VFS, "Autodisabling the use of server inode numbers on %s. This server doesn't seem to support them properly. Hardlinks will not be recognized on this mount. Consider mounting with the \"noserverino\" option to silence this message.\n",
cifs_sb_master_tcon(cifs_sb)->treeName);
}
--
2.20.1