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 | 18 ++++++++++-
fs/cifs/cifsglob.h | 5 +++
fs/cifs/connect.c | 90 ++++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 112 insertions(+), 1 deletions(-)
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 44394c8..b915417 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -641,6 +641,7 @@ cifs_do_mount(struct file_system_type *fs_type,
struct super_block *sb;
struct cifs_sb_info *cifs_sb;
struct smb_vol *volume_info;
+ struct cifs_mnt_data mnt_data;
struct dentry *root;
char *copied_data = NULL;
@@ -658,13 +659,21 @@ cifs_do_mount(struct file_system_type *fs_type,
cifs_setup_cifs_sb(volume_info, cifs_sb);
- sb = sget(fs_type, NULL, set_anon_super, NULL);
+ mnt_data.vol = volume_info;
+ mnt_data.cifs_sb = cifs_sb;
+
+ sb = sget(fs_type, cifs_match_super, set_anon_super, &mnt_data);
if (IS_ERR(sb)) {
kfree(cifs_sb);
root = ERR_CAST(sb);
goto out;
}
+ if (sb->s_fs_info) {
+ cFYI(1, "Use existing superblock");
+ goto out_shared;
+ }
+
sb->s_flags = flags;
/*
@@ -697,6 +706,13 @@ out:
cifs_cleanup_volume_info(&volume_info);
return root;
+out_shared:
+ root = cifs_get_root(volume_info, sb);
+ if (root)
+ cFYI(1, "dentry root is: %p", root);
+ cifs_cleanup_volume_info(&volume_info);
+ return root;
+
err_out:
kfree(cifs_sb);
deactivate_locked_super(sb);
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 38754f0..188be0c 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -214,6 +214,11 @@ struct smb_vol {
struct nls_table *local_nls;
};
+struct cifs_mnt_data {
+ struct cifs_sb_info *cifs_sb;
+ struct smb_vol *vol;
+};
+
struct TCP_Server_Info {
struct list_head tcp_ses_list;
struct list_head smb_ses_list;
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index abd5775..c114159 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -2139,6 +2139,96 @@ cifs_put_tlink(struct tcon_link *tlink)
return;
}
+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 cifs_sb_info *old, struct cifs_sb_info *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 (strcmp(old->local_nls->charset, new->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 cifs_mnt_data *mnt_data = (struct cifs_mnt_data *)data;
+ struct smb_vol *volume_info;
+ struct cifs_sb_info *cifs_sb, *new_cifs_sb;
+ struct TCP_Server_Info *tcp_srv;
+ struct cifs_ses *ses;
+ struct cifs_tcon *tcon;
+ 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)) {
+ spin_unlock(&cifs_tcp_ses_lock);
+ return rc;
+ }
+ tcon = tlink_tcon(tlink);
+ ses = tcon->ses;
+ tcp_srv = ses->server;
+
+ volume_info = mnt_data->vol;
+ new_cifs_sb = mnt_data->cifs_sb;
+
+ 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(cifs_sb, new_cifs_sb);
+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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