On Thu, 26 May 2011 20:28:51 +0400
Pavel Shilovsky <piastry@xxxxxxxxxxx> wrote:
> 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.
>
> Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
> Signed-off-by: Pavel Shilovsky <piastry@xxxxxxxxxxx>
> ---
> fs/cifs/cifsfs.c | 19 +++++++++-
> fs/cifs/cifsglob.h | 19 ++++++++++
> fs/cifs/connect.c | 98 ++++++++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 135 insertions(+), 1 deletions(-)
>
> diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
> index 46fdd55..360fe2e 100644
> --- a/fs/cifs/cifsfs.c
> +++ b/fs/cifs/cifsfs.c
> @@ -630,6 +630,7 @@ 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;
>
> cFYI(1, "Devname: %s flags: %d ", dev_name, flags);
> @@ -646,12 +647,21 @@ 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;
> + mnt_data.flags = flags;
> +
> + sb = sget(fs_type, cifs_match_super, set_anon_super, &mnt_data);
> if (IS_ERR(sb)) {
> root = ERR_CAST(sb);
> goto out_cifs_sb;
> }
>
> + if (sb->s_fs_info) {
> + cFYI(1, "Use existing superblock");
> + goto out_shared;
> + }
> +
> /*
> * Copy mount params for use in submounts. Better to do
> * the copy here and deal with the error before cleanup gets
> @@ -680,9 +690,16 @@ cifs_do_mount(struct file_system_type *fs_type,
> root = cifs_get_root(volume_info, sb);
> if (root == NULL)
> goto out_super;
> +
> cFYI(1, "dentry root is: %p", root);
> goto out;
>
> +out_shared:
> + root = cifs_get_root(volume_info, sb);
> + if (root)
> + cFYI(1, "dentry root is: %p", root);
> + goto out;
> +
> out_super:
> kfree(cifs_sb->mountdata);
> deactivate_locked_super(sb);
> diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
> index f57387a..7f90488 100644
> --- a/fs/cifs/cifsglob.h
> +++ b/fs/cifs/cifsglob.h
> @@ -210,6 +210,25 @@ struct smb_vol {
> struct nls_table *local_nls;
> };
>
> +#define CIFS_MOUNT_MASK (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)
> +
> +#define CIFS_MS_MASK (MS_RDONLY | MS_MANDLOCK | MS_NOEXEC | MS_NOSUID | \
> + MS_NODEV | MS_SYNCHRONOUS)
> +
> +struct cifs_mnt_data {
> + struct cifs_sb_info *cifs_sb;
> + struct smb_vol *vol;
> + int flags;
> +};
> +
> 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 4f34519..12408de 100644
> --- a/fs/cifs/connect.c
> +++ b/fs/cifs/connect.c
> @@ -2146,6 +2146,96 @@ cifs_put_tlink(struct tcon_link *tlink)
> return;
> }
>
> +static inline struct tcon_link *
> +cifs_sb_master_tlink(struct cifs_sb_info *cifs_sb);
> +
> +static int
> +compare_mount_options(struct super_block *sb, struct cifs_mnt_data *mnt_data)
> +{
> + struct cifs_sb_info *old = CIFS_SB(sb);
> + struct cifs_sb_info *new = mnt_data->cifs_sb;
> +
> + if ((sb->s_flags & CIFS_MS_MASK) != (mnt_data->flags & CIFS_MS_MASK))
> + return 0;
> +
> + if ((old->mnt_cifs_flags & CIFS_MOUNT_MASK) !=
> + (new->mnt_cifs_flags & CIFS_MOUNT_MASK))
> + return 0;
> +
> + if (old->rsize != new->rsize)
> + return 0;
> +
> + if (new->wsize && new->wsize < old->wsize)
> + return 0;
Might be nice to have a comment here explaining why we check it this
way. That can be added later though.
> +
> + 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;
> + struct TCP_Server_Info *tcp_srv;
> + struct cifsSesInfo *ses;
> + struct cifsTconInfo *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;
> +
> + 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, mnt_data);
> +out:
> + cifs_put_tlink(tlink);
> + spin_unlock(&cifs_tcp_ses_lock);
> + return rc;
> +}
> +
> int
> get_dfs_path(int xid, struct cifsSesInfo *pSesInfo, const char *old_path,
> const struct nls_table *nls_codepage, unsigned int *pnum_referrals,
> @@ -2571,6 +2661,14 @@ void cifs_setup_cifs_sb(struct smb_vol *pvolume_info,
> /* Windows ME may prefer this */
> cFYI(1, "readsize set to minimum: 2048");
> }
> +
> + /*
> + * Temporally set wsize for matching superblock. If we end up using
^^^
nit: Temporarily
> + * new sb then cifs_negotiate_wsize will later negotiate it downward
> + * if needed.
> + */
> + cifs_sb->wsize = pvolume_info->wsize;
> +
> cifs_sb->mnt_uid = pvolume_info->linux_uid;
> cifs_sb->mnt_gid = pvolume_info->linux_gid;
> cifs_sb->mnt_file_mode = pvolume_info->file_mode;
Other than the minor nits above, this looks fine:
Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
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