merged both into cifs-2.6.git for-next (the 2nd one earlier, so it
could be sent to a 5.6-rc ie before 5.7)
On Thu, Feb 20, 2020 at 6:08 PM ronnie sahlberg
<ronniesahlberg@xxxxxxxxx> wrote:
>
> Acked-by: Ronnie Sahlberg <lsahlber@xxxxxxxxxx>
>
> On Fri, Feb 21, 2020 at 8:50 AM Paulo Alcantara (SUSE) <pc@xxxxxx> wrote:
> >
> > For the case where we have a DFS path like below and we're currently
> > connected to targetA:
> >
> > //dfsroot/link -> //targetA/share/foo, //targetB/share/bar
> >
> > after failover, we should make sure to update cifs_sb->prepath so the
> > next operations will use the new prefix path "/bar".
> >
> > Besides, in order to simplify the use of different prefix paths,
> > enforce CIFS_MOUNT_USE_PREFIX_PATH for DFS mounts so we don't have to
> > revalidate the root dentry every time we set a new prefix path.
> >
> > Signed-off-by: Paulo Alcantara (SUSE) <pc@xxxxxx>
> > ---
> > fs/cifs/cifsproto.h | 5 +++
> > fs/cifs/cifssmb.c | 19 ++++++++---
> > fs/cifs/connect.c | 63 +++++++----------------------------
> > fs/cifs/dfs_cache.c | 38 +++++++++++++++++++++
> > fs/cifs/dfs_cache.h | 4 +++
> > fs/cifs/misc.c | 80 +++++++++++++++++++++++++++++++++++++++++++++
> > fs/cifs/smb2pdu.c | 19 ++++++++---
> > 7 files changed, 169 insertions(+), 59 deletions(-)
> >
> > diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
> > index 89eaaf46d1ca..af8e79b58b94 100644
> > --- a/fs/cifs/cifsproto.h
> > +++ b/fs/cifs/cifsproto.h
> > @@ -601,6 +601,11 @@ int smb2_parse_query_directory(struct cifs_tcon *tcon, struct kvec *rsp_iov,
> > int resp_buftype,
> > struct cifs_search_info *srch_inf);
> >
> > +struct super_block *cifs_get_tcp_super(struct TCP_Server_Info *server);
> > +void cifs_put_tcp_super(struct super_block *sb);
> > +int update_super_prepath(struct cifs_tcon *tcon, const char *prefix,
> > + size_t prefix_len);
> > +
> > #ifdef CONFIG_CIFS_DFS_UPCALL
> > static inline int get_dfs_path(const unsigned int xid, struct cifs_ses *ses,
> > const char *old_path,
> > diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
> > index 3c89569e7210..b6fa575d2d3f 100644
> > --- a/fs/cifs/cifssmb.c
> > +++ b/fs/cifs/cifssmb.c
> > @@ -162,9 +162,18 @@ static int __cifs_reconnect_tcon(const struct nls_table *nlsc,
> >
> > for (it = dfs_cache_get_tgt_iterator(&tl); it;
> > it = dfs_cache_get_next_tgt(&tl, it)) {
> > - const char *tgt = dfs_cache_get_tgt_name(it);
> > + const char *share, *prefix;
> > + size_t share_len, prefix_len;
> >
> > - extract_unc_hostname(tgt, &dfs_host, &dfs_host_len);
> > + rc = dfs_cache_get_tgt_share(it, &share, &share_len, &prefix,
> > + &prefix_len);
> > + if (rc) {
> > + cifs_dbg(VFS, "%s: failed to parse target share %d\n",
> > + __func__, rc);
> > + continue;
> > + }
> > +
> > + extract_unc_hostname(share, &dfs_host, &dfs_host_len);
> >
> > if (dfs_host_len != tcp_host_len
> > || strncasecmp(dfs_host, tcp_host, dfs_host_len) != 0) {
> > @@ -175,11 +184,13 @@ static int __cifs_reconnect_tcon(const struct nls_table *nlsc,
> > continue;
> > }
> >
> > - scnprintf(tree, MAX_TREE_SIZE, "\\%s", tgt);
> > + scnprintf(tree, MAX_TREE_SIZE, "\\%.*s", (int)share_len, share);
> >
> > rc = CIFSTCon(0, tcon->ses, tree, tcon, nlsc);
> > - if (!rc)
> > + if (!rc) {
> > + rc = update_super_prepath(tcon, prefix, prefix_len);
> > break;
> > + }
> > if (rc == -EREMOTE)
> > break;
> > }
> > diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
> > index 4804d1df8c1c..e2196b363765 100644
> > --- a/fs/cifs/connect.c
> > +++ b/fs/cifs/connect.c
> > @@ -57,7 +57,6 @@
> > #include "smb2proto.h"
> > #include "smbdirect.h"
> > #include "dns_resolve.h"
> > -#include "cifsfs.h"
> > #ifdef CONFIG_CIFS_DFS_UPCALL
> > #include "dfs_cache.h"
> > #endif
> > @@ -389,54 +388,7 @@ static inline int reconn_set_ipaddr(struct TCP_Server_Info *server)
> > #endif
> >
> > #ifdef CONFIG_CIFS_DFS_UPCALL
> > -struct super_cb_data {
> > - struct TCP_Server_Info *server;
> > - struct super_block *sb;
> > -};
> > -
> > /* These functions must be called with server->srv_mutex held */
> > -
> > -static void super_cb(struct super_block *sb, void *arg)
> > -{
> > - struct super_cb_data *d = arg;
> > - struct cifs_sb_info *cifs_sb;
> > - struct cifs_tcon *tcon;
> > -
> > - if (d->sb)
> > - return;
> > -
> > - cifs_sb = CIFS_SB(sb);
> > - tcon = cifs_sb_master_tcon(cifs_sb);
> > - if (tcon->ses->server == d->server)
> > - d->sb = sb;
> > -}
> > -
> > -static struct super_block *get_tcp_super(struct TCP_Server_Info *server)
> > -{
> > - struct super_cb_data d = {
> > - .server = server,
> > - .sb = NULL,
> > - };
> > -
> > - iterate_supers_type(&cifs_fs_type, super_cb, &d);
> > -
> > - if (unlikely(!d.sb))
> > - return ERR_PTR(-ENOENT);
> > - /*
> > - * Grab an active reference in order to prevent automounts (DFS links)
> > - * of expiring and then freeing up our cifs superblock pointer while
> > - * we're doing failover.
> > - */
> > - cifs_sb_active(d.sb);
> > - return d.sb;
> > -}
> > -
> > -static inline void put_tcp_super(struct super_block *sb)
> > -{
> > - if (!IS_ERR_OR_NULL(sb))
> > - cifs_sb_deactive(sb);
> > -}
> > -
> > static void reconn_inval_dfs_target(struct TCP_Server_Info *server,
> > struct cifs_sb_info *cifs_sb,
> > struct dfs_cache_tgt_list *tgt_list,
> > @@ -508,7 +460,7 @@ cifs_reconnect(struct TCP_Server_Info *server)
> > server->nr_targets = 1;
> > #ifdef CONFIG_CIFS_DFS_UPCALL
> > spin_unlock(&GlobalMid_Lock);
> > - sb = get_tcp_super(server);
> > + sb = cifs_get_tcp_super(server);
> > if (IS_ERR(sb)) {
> > rc = PTR_ERR(sb);
> > cifs_dbg(FYI, "%s: will not do DFS failover: rc = %d\n",
> > @@ -535,7 +487,7 @@ cifs_reconnect(struct TCP_Server_Info *server)
> > spin_unlock(&GlobalMid_Lock);
> > #ifdef CONFIG_CIFS_DFS_UPCALL
> > dfs_cache_free_tgts(&tgt_list);
> > - put_tcp_super(sb);
> > + cifs_put_tcp_super(sb);
> > #endif
> > return rc;
> > } else
> > @@ -666,7 +618,7 @@ cifs_reconnect(struct TCP_Server_Info *server)
> >
> > }
> >
> > - put_tcp_super(sb);
> > + cifs_put_tcp_super(sb);
> > #endif
> > if (server->tcpStatus == CifsNeedNegotiate)
> > mod_delayed_work(cifsiod_wq, &server->echo, 0);
> > @@ -4999,6 +4951,15 @@ int cifs_mount(struct cifs_sb_info *cifs_sb, struct smb_vol *vol)
> > * dentry revalidation to think the dentry are stale (ESTALE).
> > */
> > cifs_autodisable_serverino(cifs_sb);
> > + /*
> > + * Force the use of prefix path to support failover on DFS paths that
> > + * resolve to targets that have different prefix paths.
> > + */
> > + cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
> > + kfree(cifs_sb->prepath);
> > + cifs_sb->prepath = vol->prepath;
> > + vol->prepath = NULL;
> > +
> > out:
> > free_xid(xid);
> > cifs_try_adding_channels(ses);
> > diff --git a/fs/cifs/dfs_cache.c b/fs/cifs/dfs_cache.c
> > index 43c1b43a07ec..a67f88bf7ae1 100644
> > --- a/fs/cifs/dfs_cache.c
> > +++ b/fs/cifs/dfs_cache.c
> > @@ -1260,6 +1260,44 @@ void dfs_cache_del_vol(const char *fullpath)
> > kref_put(&vi->refcnt, vol_release);
> > }
> >
> > +/**
> > + * dfs_cache_get_tgt_share - parse a DFS target
> > + *
> > + * @it: DFS target iterator.
> > + * @share: tree name.
> > + * @share_len: length of tree name.
> > + * @prefix: prefix path.
> > + * @prefix_len: length of prefix path.
> > + *
> > + * Return zero if target was parsed correctly, otherwise non-zero.
> > + */
> > +int dfs_cache_get_tgt_share(const struct dfs_cache_tgt_iterator *it,
> > + const char **share, size_t *share_len,
> > + const char **prefix, size_t *prefix_len)
> > +{
> > + char *s, sep;
> > +
> > + if (!it || !share || !share_len || !prefix || !prefix_len)
> > + return -EINVAL;
> > +
> > + sep = it->it_name[0];
> > + if (sep != '\\' && sep != '/')
> > + return -EINVAL;
> > +
> > + s = strchr(it->it_name + 1, sep);
> > + if (!s)
> > + return -EINVAL;
> > +
> > + s = strchrnul(s + 1, sep);
> > +
> > + *share = it->it_name;
> > + *share_len = s - it->it_name;
> > + *prefix = *s ? s + 1 : s;
> > + *prefix_len = &it->it_name[strlen(it->it_name)] - *prefix;
> > +
> > + return 0;
> > +}
> > +
> > /* Get all tcons that are within a DFS namespace and can be refreshed */
> > static void get_tcons(struct TCP_Server_Info *server, struct list_head *head)
> > {
> > diff --git a/fs/cifs/dfs_cache.h b/fs/cifs/dfs_cache.h
> > index 99ee44f8ad07..bf94d08cfb5a 100644
> > --- a/fs/cifs/dfs_cache.h
> > +++ b/fs/cifs/dfs_cache.h
> > @@ -49,6 +49,10 @@ extern int dfs_cache_update_vol(const char *fullpath,
> > struct TCP_Server_Info *server);
> > extern void dfs_cache_del_vol(const char *fullpath);
> >
> > +extern int dfs_cache_get_tgt_share(const struct dfs_cache_tgt_iterator *it,
> > + const char **share, size_t *share_len,
> > + const char **prefix, size_t *prefix_len);
> > +
> > static inline struct dfs_cache_tgt_iterator *
> > dfs_cache_get_next_tgt(struct dfs_cache_tgt_list *tl,
> > struct dfs_cache_tgt_iterator *it)
> > diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
> > index 40ca394fd5de..a456febd4109 100644
> > --- a/fs/cifs/misc.c
> > +++ b/fs/cifs/misc.c
> > @@ -31,6 +31,7 @@
> > #include "nterr.h"
> > #include "cifs_unicode.h"
> > #include "smb2pdu.h"
> > +#include "cifsfs.h"
> >
> > extern mempool_t *cifs_sm_req_poolp;
> > extern mempool_t *cifs_req_poolp;
> > @@ -1022,3 +1023,82 @@ int copy_path_name(char *dst, const char *src)
> > name_len++;
> > return name_len;
> > }
> > +
> > +struct super_cb_data {
> > + struct TCP_Server_Info *server;
> > + struct super_block *sb;
> > +};
> > +
> > +static void super_cb(struct super_block *sb, void *arg)
> > +{
> > + struct super_cb_data *d = arg;
> > + struct cifs_sb_info *cifs_sb;
> > + struct cifs_tcon *tcon;
> > +
> > + if (d->sb)
> > + return;
> > +
> > + cifs_sb = CIFS_SB(sb);
> > + tcon = cifs_sb_master_tcon(cifs_sb);
> > + if (tcon->ses->server == d->server)
> > + d->sb = sb;
> > +}
> > +
> > +struct super_block *cifs_get_tcp_super(struct TCP_Server_Info *server)
> > +{
> > + struct super_cb_data d = {
> > + .server = server,
> > + .sb = NULL,
> > + };
> > +
> > + iterate_supers_type(&cifs_fs_type, super_cb, &d);
> > +
> > + if (unlikely(!d.sb))
> > + return ERR_PTR(-ENOENT);
> > + /*
> > + * Grab an active reference in order to prevent automounts (DFS links)
> > + * of expiring and then freeing up our cifs superblock pointer while
> > + * we're doing failover.
> > + */
> > + cifs_sb_active(d.sb);
> > + return d.sb;
> > +}
> > +
> > +void cifs_put_tcp_super(struct super_block *sb)
> > +{
> > + if (!IS_ERR_OR_NULL(sb))
> > + cifs_sb_deactive(sb);
> > +}
> > +
> > +int update_super_prepath(struct cifs_tcon *tcon, const char *prefix,
> > + size_t prefix_len)
> > +{
> > + struct super_block *sb;
> > + struct cifs_sb_info *cifs_sb;
> > + int rc = 0;
> > +
> > + sb = cifs_get_tcp_super(tcon->ses->server);
> > + if (IS_ERR(sb))
> > + return PTR_ERR(sb);
> > +
> > + cifs_sb = CIFS_SB(sb);
> > +
> > + kfree(cifs_sb->prepath);
> > +
> > + if (*prefix && prefix_len) {
> > + cifs_sb->prepath = kstrndup(prefix, prefix_len, GFP_ATOMIC);
> > + if (!cifs_sb->prepath) {
> > + rc = -ENOMEM;
> > + goto out;
> > + }
> > +
> > + convert_delimiter(cifs_sb->prepath, CIFS_DIR_SEP(cifs_sb));
> > + } else
> > + cifs_sb->prepath = NULL;
> > +
> > + cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
> > +
> > +out:
> > + cifs_put_tcp_super(sb);
> > + return rc;
> > +}
> > diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
> > index abc0a0512181..49b15a488ede 100644
> > --- a/fs/cifs/smb2pdu.c
> > +++ b/fs/cifs/smb2pdu.c
> > @@ -193,9 +193,18 @@ static int __smb2_reconnect(const struct nls_table *nlsc,
> >
> > for (it = dfs_cache_get_tgt_iterator(&tl); it;
> > it = dfs_cache_get_next_tgt(&tl, it)) {
> > - const char *tgt = dfs_cache_get_tgt_name(it);
> > + const char *share, *prefix;
> > + size_t share_len, prefix_len;
> >
> > - extract_unc_hostname(tgt, &dfs_host, &dfs_host_len);
> > + rc = dfs_cache_get_tgt_share(it, &share, &share_len, &prefix,
> > + &prefix_len);
> > + if (rc) {
> > + cifs_dbg(VFS, "%s: failed to parse target share %d\n",
> > + __func__, rc);
> > + continue;
> > + }
> > +
> > + extract_unc_hostname(share, &dfs_host, &dfs_host_len);
> >
> > if (dfs_host_len != tcp_host_len
> > || strncasecmp(dfs_host, tcp_host, dfs_host_len) != 0) {
> > @@ -206,11 +215,13 @@ static int __smb2_reconnect(const struct nls_table *nlsc,
> > continue;
> > }
> >
> > - scnprintf(tree, MAX_TREE_SIZE, "\\%s", tgt);
> > + scnprintf(tree, MAX_TREE_SIZE, "\\%.*s", (int)share_len, share);
> >
> > rc = SMB2_tcon(0, tcon->ses, tree, tcon, nlsc);
> > - if (!rc)
> > + if (!rc) {
> > + rc = update_super_prepath(tcon, prefix, prefix_len);
> > break;
> > + }
> > if (rc == -EREMOTE)
> > break;
> > }
> > --
> > 2.25.0
> >
--
Thanks,
Steve
