From b9b3b6a86c3c6d34a89201e45837435af5e66441 Mon Sep 17 00:00:00 2001
From: Steve French <stfrench@microsoft.com>
Date: Fri, 30 Aug 2019 02:12:41 -0500
Subject: [PATCH] smb3: add mount option to allow RW caching of share accessed
by only 1 client
If a share is known to be only to be accessed by one client, we
can aggressively cache writes not just reads to it.
Add "cache=" option (cache=singleclient) for mounting read write shares
(that will not be read or written to from other clients while we have
it mounted) in order to improve performance.
Signed-off-by: Steve French <stfrench@microsoft.com>
---
fs/cifs/cifs_fs_sb.h | 1 +
fs/cifs/cifsfs.c | 2 ++
fs/cifs/cifsglob.h | 5 +++--
fs/cifs/connect.c | 20 +++++++++++++++++++-
4 files changed, 25 insertions(+), 3 deletions(-)
@@ -54,6 +54,7 @@
#define CIFS_MOUNT_NO_DFS 0x8000000 /* disable DFS resolving */
#define CIFS_MOUNT_MODE_FROM_SID 0x10000000 /* retrieve mode from special ACE */
#define CIFS_MOUNT_RO_CACHE 0x20000000 /* assumes share will not change */
+#define CIFS_MOUNT_RW_CACHE 0x40000000 /* assumes only client accessing */
struct cifs_sb_info {
struct rb_root tlink_tree;
@@ -400,6 +400,8 @@ cifs_show_cache_flavor(struct seq_file *s, struct cifs_sb_info *cifs_sb)
seq_puts(s, "strict");
else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_DIRECT_IO)
seq_puts(s, "none");
+ else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RW_CACHE)
+ seq_puts(s, "singleclient"); /* assume only one client access */
else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RO_CACHE)
seq_puts(s, "ro"); /* read only caching assumed */
else
@@ -560,6 +560,7 @@ struct smb_vol {
bool direct_io:1;
bool strict_io:1; /* strict cache behavior */
bool cache_ro:1;
+ bool cache_rw: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. */
@@ -622,7 +623,7 @@ struct smb_vol {
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_RO_CACHE)
+ CIFS_MOUNT_RO_CACHE | CIFS_MOUNT_RW_CACHE)
/**
* Generic VFS superblock mount flags (s_flags) to consider when
@@ -1370,7 +1371,7 @@ void cifsFileInfo_put(struct cifsFileInfo *cifs_file);
#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)
+#define CIFS_CACHE_WRITE(cinode) ((cinode->oplock & CIFS_CACHE_WRITE_FLG) || (CIFS_SB(cinode->vfs_inode.i_sb)->mnt_cifs_flags & CIFS_MOUNT_RW_CACHE))
/*
* One of these for each file inode
@@ -299,6 +299,7 @@ enum {
Opt_cache_strict,
Opt_cache_none,
Opt_cache_ro,
+ Opt_cache_rw,
Opt_cache_err
};
@@ -307,6 +308,7 @@ static const match_table_t cifs_cacheflavor_tokens = {
{ Opt_cache_strict, "strict" },
{ Opt_cache_none, "none" },
{ Opt_cache_ro, "ro" },
+ { Opt_cache_rw, "singleclient" },
{ Opt_cache_err, NULL }
};
@@ -1421,21 +1423,31 @@ cifs_parse_cache_flavor(char *value, struct smb_vol *vol)
vol->direct_io = false;
vol->strict_io = false;
vol->cache_ro = false;
+ vol->cache_rw = false;
break;
case Opt_cache_strict:
vol->direct_io = false;
vol->strict_io = true;
vol->cache_ro = false;
+ vol->cache_rw = false;
break;
case Opt_cache_none:
vol->direct_io = true;
vol->strict_io = false;
vol->cache_ro = false;
+ vol->cache_rw = false;
break;
case Opt_cache_ro:
vol->direct_io = false;
vol->strict_io = false;
vol->cache_ro = true;
+ vol->cache_rw = false;
+ break;
+ case Opt_cache_rw:
+ vol->direct_io = false;
+ vol->strict_io = false;
+ vol->cache_ro = false;
+ vol->cache_rw = true;
break;
default:
cifs_dbg(VFS, "bad cache= option: %s\n", value);
@@ -4054,6 +4066,10 @@ int cifs_setup_cifs_sb(struct smb_vol *pvolume_info,
if (pvolume_info->cache_ro) {
cifs_dbg(VFS, "mounting share with read only caching. Ensure that the share will not be modified while in use.\n");
cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_RO_CACHE;
+ } else if (pvolume_info->cache_rw) {
+ cifs_dbg(VFS, "mounting share in single client RW caching mode. Ensure that no other systems will be accessing the share.\n");
+ cifs_sb->mnt_cifs_flags |= (CIFS_MOUNT_RO_CACHE |
+ CIFS_MOUNT_RW_CACHE);
}
if (pvolume_info->mfsymlinks) {
if (pvolume_info->sfu_emul) {
@@ -4203,8 +4219,10 @@ static int mount_get_conns(struct smb_vol *vol, struct cifs_sb_info *cifs_sb,
if (tcon->fsDevInfo.DeviceCharacteristics &
FILE_READ_ONLY_DEVICE)
cifs_dbg(VFS, "mounted to read only share\n");
- else
+ else if ((cifs_sb->mnt_cifs_flags &
+ CIFS_MOUNT_RW_CACHE) == 0)
cifs_dbg(VFS, "read only mount of RW share\n");
+ /* no need to log a RW mount of a typical RW share */
}
}
--
2.20.1
Similar to the "cache=ro" patch but for the read write case ... smb3: add mount option to allow RW caching of share accessed by only 1 client If a share is known to be only to be accessed by one client, we can aggressively cache writes not just reads to it. Add "cache=" option (cache=singleclient) for mounting read write shares (that will not be read or written to from other clients while we have it mounted) in order to improve performance.