smb3: add mount option to allow forced caching of read only share
If a share is immutable (at least for the period that it will
be mounted) it would be helpful to not have to revalidate
dentries repeatedly that we know can not be changed remotely.
Add "cache=" option (cache=ro) for mounting read only shares
in order to improve performance in cases in which we know that
the share will not be changing while it is in use.
Signed-off-by: Steve French <stfrench@microsoft.com>
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index fe610e7..3f12da7 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -559,6 +559,7 @@ struct smb_vol {
bool server_ino:1; /* use inode numbers from server ie UniqueId */
bool direct_io:1;
bool strict_io:1; /* strict cache behavior */
+ bool cache_ro:1;
bool remap:1; /* set to remap seven reserved chars in filenames */
bool sfu_remap:1; /* remap seven reserved chars ala SFU */
bool posix_paths:1; /* unset to not ask for posix pathnames. */
@@ -620,7 +621,8 @@ struct smb_vol {
CIFS_MOUNT_MULTIUSER | CIFS_MOUNT_STRICT_IO | \
CIFS_MOUNT_CIFS_BACKUPUID | CIFS_MOUNT_CIFS_BACKUPGID | \
CIFS_MOUNT_UID_FROM_ACL | CIFS_MOUNT_NO_HANDLE_CACHE | \
- CIFS_MOUNT_NO_DFS | CIFS_MOUNT_MODE_FROM_SID)
+ CIFS_MOUNT_NO_DFS | CIFS_MOUNT_MODE_FROM_SID | \
+ CIFS_MOUNT_RO_CACHE)
/**
* Generic VFS superblock mount flags (s_flags) to consider when
@@ -1366,7 +1368,7 @@ void cifsFileInfo_put(struct cifsFileInfo *cifs_file);
#define CIFS_CACHE_RW_FLG (CIFS_CACHE_READ_FLG | CIFS_CACHE_WRITE_FLG)
#define CIFS_CACHE_RHW_FLG (CIFS_CACHE_RW_FLG | CIFS_CACHE_HANDLE_FLG)
-#define CIFS_CACHE_READ(cinode) (cinode->oplock & CIFS_CACHE_READ_FLG)
+#define CIFS_CACHE_READ(cinode) ((cinode->oplock & CIFS_CACHE_READ_FLG) || (CIFS_SB(cinode->vfs_inode.i_sb)->mnt_cifs_flags & CIFS_MOUNT_RO_CACHE))
#define CIFS_CACHE_HANDLE(cinode) (cinode->oplock & CIFS_CACHE_HANDLE_FLG)
#define CIFS_CACHE_WRITE(cinode) (cinode->oplock & CIFS_CACHE_WRITE_FLG)