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CIFS: Migrate to shared superblock model

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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@redhat.com>
Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Steve French <sfrench@us.ibm.com>
This commit is contained in:
Pavel Shilovsky 2011-05-26 23:35:47 +04:00 committed by Steve French
parent f87d39d951
commit 25c7f41e92
3 changed files with 139 additions and 1 deletions
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19
fs/cifs/cifsfs.c
View File

@ -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);

19
fs/cifs/cifsglob.h
View File

@ -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;

102
fs/cifs/connect.c
View File

@ -2146,6 +2146,100 @@ 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;
/*
* We want to share sb only if we don't specify wsize or specified wsize
* is greater or equal than existing one.
*/
if (new->wsize && new->wsize < old->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;
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,
@ -2578,6 +2672,14 @@ void cifs_setup_cifs_sb(struct smb_vol *pvolume_info,
/* Windows ME may prefer this */
cFYI(1, "readsize set to minimum: 2048");
}
/*
* Temporarily set wsize for matching superblock. If we end up using
* 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;