Commit 41e033fe authored by Steve French's avatar Steve French
Browse files

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: default avatarSteve French <stfrench@microsoft.com>
parent 1981ebaa

fs/cifs/cifs_fs_sb.h

+1 −0
Original line number Diff line number Diff line
@@ -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;

fs/cifs/cifsfs.c

+2 −0
Original line number Diff line number Diff line
@@ -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

fs/cifs/cifsglob.h

+3 −2
Original line number Diff line number Diff line
@@ -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

fs/cifs/connect.c

+19 −1
Original line number Diff line number Diff line
@@ -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 */

		}

	}

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