Add cifs_match_super to use in sget to share superblock between mounts
that have the same //server/sharename, credentials and mount options.
It helps us to improve performance on work with future SMB2.1 leases.
Signed-off-by: Pavel Shilovsky <piastry@xxxxxxxxxxx>
---
fs/cifs/cifsfs.c | 6 ++-
fs/cifs/connect.c | 93 +++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 97 insertions(+), 2 deletions(-)
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index c40c1f4..abc8436 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -577,14 +577,16 @@ cifs_do_mount(struct file_system_type *fs_type,
if (rc)
return ERR_PTR(rc);
- sb = sget(fs_type, NULL, set_anon_super, NULL);
+ sb = sget(fs_type, cifs_match_super, set_anon_super, volume_info);
if (IS_ERR(sb)) {
cifs_cleanup_volume_info(&volume_info);
return ERR_CAST(sb);
}
- if (sb->s_fs_info)
+ if (sb->s_fs_info) {
+ cFYI(1, "Use existing superblock");
goto out;
+ }
sb->s_flags = flags;
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 53b79e7..7c98c36 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -2193,6 +2193,99 @@ cifs_put_tlink(struct tcon_link *tlink)
return;
}
+static void setup_cifs_sb(struct smb_vol *vol, struct cifs_sb_info *sb);
+static inline struct tcon_link *
+cifs_sb_master_tlink(struct cifs_sb_info *cifs_sb);
+
+static const u32 ACTUAL_MOUNT_FLAGS = CIFS_MOUNT_NO_PERM | CIFS_MOUNT_SET_UID |
+ CIFS_MOUNT_SERVER_INUM | CIFS_MOUNT_DIRECT_IO | CIFS_MOUNT_NO_XATTR |
+ CIFS_MOUNT_MAP_SPECIAL_CHR | CIFS_MOUNT_UNX_EMUL | CIFS_MOUNT_NO_BRL |
+ CIFS_MOUNT_CIFS_ACL | CIFS_MOUNT_OVERR_UID | CIFS_MOUNT_OVERR_GID |
+ CIFS_MOUNT_DYNPERM | CIFS_MOUNT_NOPOSIXBRL | CIFS_MOUNT_NOSSYNC |
+ CIFS_MOUNT_FSCACHE | CIFS_MOUNT_MF_SYMLINKS | CIFS_MOUNT_MULTIUSER |
+ CIFS_MOUNT_STRICT_IO;
+
+static int
+compare_mount_options(struct super_block *sb, struct smb_vol *vol)
+{
+ struct cifs_sb_info *old = CIFS_SB(sb), new;
+
+ setup_cifs_sb(vol, &new);
+
+ if ((old->mnt_cifs_flags & ACTUAL_MOUNT_FLAGS) !=
+ (new.mnt_cifs_flags & ACTUAL_MOUNT_FLAGS))
+ return 0;
+
+ if (old->rsize != new.rsize || old->wsize != new.wsize)
+ return 0;
+
+ if (old->mnt_uid != new.mnt_uid || old->mnt_gid != new.mnt_gid)
+ return 0;
+
+ if (old->mnt_file_mode != new.mnt_file_mode ||
+ old->mnt_dir_mode != new.mnt_dir_mode)
+ return 0;
+
+ if (old->prepathlen != new.prepathlen ||
+ strncmp(old->prepath, new.prepath, old->prepathlen))
+ return 0;
+
+ if (strcmp(old->local_nls->charset, vol->local_nls->charset))
+ return 0;
+
+ if (old->actimeo != new.actimeo)
+ return 0;
+
+ return 1;
+}
+
+int
+cifs_match_super(struct super_block *sb, void *data)
+{
+ struct smb_vol *volume_info = (struct smb_vol *) data;
+ struct TCP_Server_Info *tcp_srv;
+ struct cifs_ses *ses;
+ struct cifs_tcon *tcon;
+ struct cifs_sb_info *cifs_sb;
+ struct tcon_link *tlink;
+ struct sockaddr_storage addr;
+ int rc = 0;
+
+ memset(&addr, 0, sizeof(struct sockaddr_storage));
+
+ spin_lock(&cifs_tcp_ses_lock);
+ cifs_sb = CIFS_SB(sb);
+ tlink = cifs_get_tlink(cifs_sb_master_tlink(cifs_sb));
+ if (IS_ERR(tlink))
+ goto out;
+ tcon = tlink_tcon(tlink);
+ ses = tcon->ses;
+ tcp_srv = ses->server;
+
+ if (!volume_info->UNCip || !volume_info->UNC)
+ goto out;
+
+ rc = cifs_fill_sockaddr((struct sockaddr *)&addr,
+ volume_info->UNCip,
+ strlen(volume_info->UNCip),
+ volume_info->port);
+ if (!rc)
+ goto out;
+
+ if (!match_server(tcp_srv, (struct sockaddr *)&addr, volume_info) ||
+ !match_session(ses, volume_info) ||
+ !match_tcon(tcon, volume_info->UNC)) {
+ rc = 0;
+ goto out;
+ }
+
+ rc = compare_mount_options(sb, volume_info);
+out:
+ cifs_put_tlink(tlink);
+ spin_unlock(&cifs_tcp_ses_lock);
+ return rc;
+}
+
int
get_dfs_path(int xid, struct cifs_ses *pSesInfo, const char *old_path,
const struct nls_table *nls_codepage, unsigned int *pnum_referrals,
--
1.7.1
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