From: Paulo Alcantara <palcantara@suse.de>
Date: Wed, 14 Nov 2018 13:03:14 -0200
Subject: [PATCH] cifs: Refactor out cifs_mount()
Git-commit: 56c762eb9bee330bb4e6d11c589434f2904d3ab6
Patch-mainline: v5.0-rc1
References: bsc#1144333
* Split and refactor the very large function cifs_mount() in multiple
functions:
- tcp, ses and tcon setup to mount_get_conns()
- tcp, ses and tcon cleanup in mount_put_conns()
- tcon tlink setup to mount_setup_tlink()
- remote path checking to is_path_remote()
* Implement 2 version of cifs_mount() for DFS-enabled builds and
non-DFS-enabled builds (CONFIG_CIFS_DFS_UPCALL).
In preparation for DFS failover support.
Signed-off-by: Paulo Alcantara <palcantara@suse.de>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Aurelien Aptel <aaptel@suse.com>
---
fs/cifs/cifsproto.h | 4 +-
fs/cifs/connect.c | 441 ++++++++++++++++++++++++++++++----------------------
2 files changed, 262 insertions(+), 183 deletions(-)
diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index fa361bc00602..f4dd2a3795dd 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -213,7 +213,7 @@ extern int cifs_match_super(struct super_block *, void *);
extern void cifs_cleanup_volume_info(struct smb_vol *pvolume_info);
extern struct smb_vol *cifs_get_volume_info(char *mount_data,
const char *devname, bool is_smb3);
-extern int cifs_mount(struct cifs_sb_info *, struct smb_vol *);
+extern int cifs_mount(struct cifs_sb_info *cifs_sb, struct smb_vol *vol);
extern void cifs_umount(struct cifs_sb_info *);
extern void cifs_mark_open_files_invalid(struct cifs_tcon *tcon);
extern void cifs_reopen_persistent_handles(struct cifs_tcon *tcon);
@@ -524,6 +524,8 @@ extern int E_md4hash(const unsigned char *passwd, unsigned char *p16,
const struct nls_table *codepage);
extern int SMBencrypt(unsigned char *passwd, const unsigned char *c8,
unsigned char *p24);
+extern void
+cifs_cleanup_volume_info_contents(struct smb_vol *volume_info);
void cifs_readdata_release(struct kref *refcount);
int cifs_async_readv(struct cifs_readdata *rdata);
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index e4a924ba6325..944188d6200c 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -3747,8 +3747,8 @@ int cifs_setup_cifs_sb(struct smb_vol *pvolume_info,
return 0;
}
-static void
-cleanup_volume_info_contents(struct smb_vol *volume_info)
+void
+cifs_cleanup_volume_info_contents(struct smb_vol *volume_info)
{
kfree(volume_info->username);
kzfree(volume_info->password);
@@ -3763,10 +3763,136 @@ cifs_cleanup_volume_info(struct smb_vol *volume_info)
{
if (!volume_info)
return;
- cleanup_volume_info_contents(volume_info);
+ cifs_cleanup_volume_info_contents(volume_info);
kfree(volume_info);
}
+/* Release all succeed connections */
+static inline void mount_put_conns(struct cifs_sb_info *cifs_sb,
+ unsigned int xid,
+ struct TCP_Server_Info *server,
+ struct cifs_ses *ses, struct cifs_tcon *tcon)
+{
+ int rc = 0;
+
+ if (tcon)
+ cifs_put_tcon(tcon);
+ else if (ses)
+ cifs_put_smb_ses(ses);
+ else if (server)
+ cifs_put_tcp_session(server, 0);
+ cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_POSIX_PATHS;
+ free_xid(xid);
+}
+
+/* Get connections for tcp, ses and tcon */
+static int mount_get_conns(struct smb_vol *vol, struct cifs_sb_info *cifs_sb,
+ unsigned int *xid,
+ struct TCP_Server_Info **nserver,
+ struct cifs_ses **nses, struct cifs_tcon **ntcon)
+{
+ int rc = 0;
+ struct TCP_Server_Info *server;
+ struct cifs_ses *ses;
+ struct cifs_tcon *tcon;
+
+ *nserver = NULL;
+ *nses = NULL;
+ *ntcon = NULL;
+
+ *xid = get_xid();
+
+ /* get a reference to a tcp session */
+ server = cifs_get_tcp_session(vol);
+ if (IS_ERR(server)) {
+ rc = PTR_ERR(server);
+ return rc;
+ }
+
+ *nserver = server;
+
+ if ((vol->max_credits < 20) || (vol->max_credits > 60000))
+ server->max_credits = SMB2_MAX_CREDITS_AVAILABLE;
+ else
+ server->max_credits = vol->max_credits;
+
+ /* get a reference to a SMB session */
+ ses = cifs_get_smb_ses(server, vol);
+ if (IS_ERR(ses)) {
+ rc = PTR_ERR(ses);
+ return rc;
+ }
+
+ *nses = ses;
+
+ if ((vol->persistent == true) && (!(ses->server->capabilities &
+ SMB2_GLOBAL_CAP_PERSISTENT_HANDLES))) {
+ cifs_dbg(VFS, "persistent handles not supported by server\n");
+ return -EOPNOTSUPP;
+ }
+
+ /* search for existing tcon to this server share */
+ tcon = cifs_get_tcon(ses, vol);
+ if (IS_ERR(tcon)) {
+ rc = PTR_ERR(tcon);
+ return rc;
+ }
+
+ *ntcon = tcon;
+
+ /* if new SMB3.11 POSIX extensions are supported do not remap / and \ */
+ if (tcon->posix_extensions)
+ cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_POSIX_PATHS;
+
+ /* tell server which Unix caps we support */
+ if (cap_unix(tcon->ses)) {
+ /*
+ * reset of caps checks mount to see if unix extensions disabled
+ * for just this mount.
+ */
+ reset_cifs_unix_caps(*xid, tcon, cifs_sb, vol);
+ if ((tcon->ses->server->tcpStatus == CifsNeedReconnect) &&
+ (le64_to_cpu(tcon->fsUnixInfo.Capability) &
+ CIFS_UNIX_TRANSPORT_ENCRYPTION_MANDATORY_CAP))
+ return -EACCES;
+ } else
+ tcon->unix_ext = 0; /* server does not support them */
+
+ /* do not care if a following call succeed - informational */
+ if (!tcon->pipe && server->ops->qfs_tcon)
+ server->ops->qfs_tcon(*xid, tcon);
+
+ cifs_sb->wsize = server->ops->negotiate_wsize(tcon, vol);
+ cifs_sb->rsize = server->ops->negotiate_rsize(tcon, vol);
+
+ return 0;
+}
+
+static int mount_setup_tlink(struct cifs_sb_info *cifs_sb, struct cifs_ses *ses,
+ struct cifs_tcon *tcon)
+{
+ struct tcon_link *tlink;
+
+ /* hang the tcon off of the superblock */
+ tlink = kzalloc(sizeof(*tlink), GFP_KERNEL);
+ if (tlink == NULL)
+ return -ENOMEM;
+
+ tlink->tl_uid = ses->linux_uid;
+ tlink->tl_tcon = tcon;
+ tlink->tl_time = jiffies;
+ set_bit(TCON_LINK_MASTER, &tlink->tl_flags);
+ set_bit(TCON_LINK_IN_TREE, &tlink->tl_flags);
+
+ cifs_sb->master_tlink = tlink;
+ spin_lock(&cifs_sb->tlink_tree_lock);
+ tlink_rb_insert(&cifs_sb->tlink_tree, tlink);
+ spin_unlock(&cifs_sb->tlink_tree_lock);
+
+ queue_delayed_work(cifsiod_wq, &cifs_sb->prune_tlinks,
+ TLINK_IDLE_EXPIRE);
+ return 0;
+}
#ifdef CONFIG_CIFS_DFS_UPCALL
/*
@@ -3846,7 +3972,7 @@ expand_dfs_referral(const unsigned int xid, struct cifs_ses *ses,
rc = PTR_ERR(mdata);
mdata = NULL;
} else {
- cleanup_volume_info_contents(volume_info);
+ cifs_cleanup_volume_info_contents(volume_info);
rc = cifs_setup_volume_info(volume_info, mdata,
fake_devname, false);
}
@@ -3955,107 +4081,77 @@ cifs_are_all_path_components_accessible(struct TCP_Server_Info *server,
return rc;
}
-int
-cifs_mount(struct cifs_sb_info *cifs_sb, struct smb_vol *volume_info)
+/*
+ * Check if path is remote (e.g. a DFS share). Return -EREMOTE if it is,
+ * otherwise 0.
+ */
+static int is_path_remote(struct cifs_sb_info *cifs_sb, struct smb_vol *vol,
+ const unsigned int xid,
+ struct TCP_Server_Info *server,
+ struct cifs_tcon *tcon)
{
int rc;
- unsigned int xid;
- struct cifs_ses *ses;
- struct cifs_tcon *tcon;
- struct TCP_Server_Info *server;
- char *full_path;
- struct tcon_link *tlink;
-#ifdef CONFIG_CIFS_DFS_UPCALL
- int referral_walks_count = 0;
-#endif
-
-#ifdef CONFIG_CIFS_DFS_UPCALL
-try_mount_again:
- /* cleanup activities if we're chasing a referral */
- if (referral_walks_count) {
- if (tcon)
- cifs_put_tcon(tcon);
- else if (ses)
- cifs_put_smb_ses(ses);
+ char *full_path;
- cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_POSIX_PATHS;
+ if (!server->ops->is_path_accessible)
+ return -EOPNOTSUPP;
- free_xid(xid);
- }
-#endif
- rc = 0;
- tcon = NULL;
- ses = NULL;
- server = NULL;
- full_path = NULL;
- tlink = NULL;
+ /*
+ * cifs_build_path_to_root works only when we have a valid tcon
+ */
+ full_path = cifs_build_path_to_root(vol, cifs_sb, tcon,
+ tcon->Flags & SMB_SHARE_IS_IN_DFS);
+ if (full_path == NULL)
+ return -ENOMEM;
- xid = get_xid();
+ cifs_dbg(FYI, "%s: full_path: %s\n", __func__, full_path);
- /* get a reference to a tcp session */
- server = cifs_get_tcp_session(volume_info);
- if (IS_ERR(server)) {
- rc = PTR_ERR(server);
- goto out;
- }
- if ((volume_info->max_credits < 20) ||
- (volume_info->max_credits > 60000))
- server->max_credits = SMB2_MAX_CREDITS_AVAILABLE;
- else
- server->max_credits = volume_info->max_credits;
- /* get a reference to a SMB session */
- ses = cifs_get_smb_ses(server, volume_info);
- if (IS_ERR(ses)) {
- rc = PTR_ERR(ses);
- ses = NULL;
- goto mount_fail_check;
- }
-
- if ((volume_info->persistent == true) && ((ses->server->capabilities &
- SMB2_GLOBAL_CAP_PERSISTENT_HANDLES) == 0)) {
- cifs_dbg(VFS, "persistent handles not supported by server\n");
- rc = -EOPNOTSUPP;
- goto mount_fail_check;
+ rc = server->ops->is_path_accessible(xid, tcon, cifs_sb,
+ full_path);
+ if (rc != 0 && rc != -EREMOTE) {
+ kfree(full_path);
+ return rc;
}
- /* search for existing tcon to this server share */
- tcon = cifs_get_tcon(ses, volume_info);
- if (IS_ERR(tcon)) {
- rc = PTR_ERR(tcon);
- tcon = NULL;
- if (rc == -EACCES)
- goto mount_fail_check;
-
- goto remote_path_check;
+ if (rc != -EREMOTE) {
+ rc = cifs_are_all_path_components_accessible(server, xid, tcon,
+ cifs_sb,
+ full_path);
+ if (rc != 0) {
+ cifs_dbg(VFS, "cannot query dirs between root and final path, "
+ "enabling CIFS_MOUNT_USE_PREFIX_PATH\n");
+ cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
+ rc = 0;
+ }
}
- /* if new SMB3.11 POSIX extensions are supported do not remap / and \ */
- if (tcon->posix_extensions)
- cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_POSIX_PATHS;
+ kfree(full_path);
+ return rc;
+}
- /* tell server which Unix caps we support */
- if (cap_unix(tcon->ses)) {
- /* reset of caps checks mount to see if unix extensions
- disabled for just this mount */
- reset_cifs_unix_caps(xid, tcon, cifs_sb, volume_info);
- if ((tcon->ses->server->tcpStatus == CifsNeedReconnect) &&
- (le64_to_cpu(tcon->fsUnixInfo.Capability) &
- CIFS_UNIX_TRANSPORT_ENCRYPTION_MANDATORY_CAP)) {
- rc = -EACCES;
- goto mount_fail_check;
- }
- } else
- tcon->unix_ext = 0; /* server does not support them */
+#ifdef CONFIG_CIFS_DFS_UPCALL
+int cifs_mount(struct cifs_sb_info *cifs_sb, struct smb_vol *vol)
+{
+ int rc = 0;
+ unsigned int xid;
+ struct cifs_ses *ses;
+ struct cifs_tcon *tcon = NULL;
+ struct TCP_Server_Info *server;
+ char *old_mountdata;
+ int count;
- /* do not care if a following call succeed - informational */
- if (!tcon->pipe && server->ops->qfs_tcon)
- server->ops->qfs_tcon(xid, tcon);
+ rc = mount_get_conns(vol, cifs_sb, &xid, &server, &ses, &tcon);
+ if (!rc && tcon) {
+ rc = is_path_remote(cifs_sb, vol, xid, server, tcon);
+ if (!rc)
+ goto out;
+ if (rc != -EREMOTE)
+ goto error;
+ }
+ if ((rc == -EACCES) || (rc == -EOPNOTSUPP) || (ses == NULL) || (server == NULL))
+ goto error;
- cifs_sb->wsize = server->ops->negotiate_wsize(tcon, volume_info);
- cifs_sb->rsize = server->ops->negotiate_rsize(tcon, volume_info);
-remote_path_check:
-#ifdef CONFIG_CIFS_DFS_UPCALL
/*
* Perform an unconditional check for whether there are DFS
* referrals for this path without prefix, to provide support
@@ -4063,119 +4159,100 @@ cifs_mount(struct cifs_sb_info *cifs_sb, struct smb_vol *volume_info)
* with PATH_NOT_COVERED to requests that include the prefix.
* Chase the referral if found, otherwise continue normally.
*/
- if (referral_walks_count == 0) {
- int refrc = expand_dfs_referral(xid, ses, volume_info, cifs_sb,
- false);
- if (!refrc) {
- referral_walks_count++;
- goto try_mount_again;
- }
+ old_mountdata = cifs_sb->mountdata;
+ (void)expand_dfs_referral(xid, ses, vol, cifs_sb, false);
+
+ if (cifs_sb->mountdata == NULL) {
+ rc = -ENOENT;
+ goto error;
}
-#endif
- /* check if a whole path is not remote */
- if (!rc && tcon) {
- if (!server->ops->is_path_accessible) {
- rc = -ENOSYS;
- goto mount_fail_check;
+ if (cifs_sb->mountdata != old_mountdata) {
+ /* If we were redirected, reconnect to new target server */
+ mount_put_conns(cifs_sb, xid, server, ses, tcon);
+ rc = mount_get_conns(vol, cifs_sb, &xid, &server, &ses, &tcon);
+ }
+ if (rc) {
+ if (rc == -EACCES || rc == -EOPNOTSUPP)
+ goto error;
+ }
+
+ for (count = 1; ;) {
+ if (!rc && tcon) {
+ rc = is_path_remote(cifs_sb, vol, xid, server, tcon);
+ if (!rc || rc != -EREMOTE)
+ break;
}
/*
- * cifs_build_path_to_root works only when we have a valid tcon
+ * BB: when we implement proper loop detection,
+ * we will remove this check. But now we need it
+ * to prevent an indefinite loop if 'DFS tree' is
+ * misconfigured (i.e. has loops).
*/
- full_path = cifs_build_path_to_root(volume_info, cifs_sb, tcon,
- tcon->Flags & SMB_SHARE_IS_IN_DFS);
- if (full_path == NULL) {
- rc = -ENOMEM;
- goto mount_fail_check;
- }
- rc = server->ops->is_path_accessible(xid, tcon, cifs_sb,
- full_path);
- if (rc != 0 && rc != -EREMOTE) {
- kfree(full_path);
- goto mount_fail_check;
- }
-
- if (rc != -EREMOTE) {
- rc = cifs_are_all_path_components_accessible(server,
- xid, tcon, cifs_sb,
- full_path);
- if (rc != 0) {
- cifs_dbg(VFS, "cannot query dirs between root and final path, "
- "enabling CIFS_MOUNT_USE_PREFIX_PATH\n");
- cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
- rc = 0;
- }
- }
- kfree(full_path);
- }
-
- /* get referral if needed */
- if (rc == -EREMOTE) {
-#ifdef CONFIG_CIFS_DFS_UPCALL
- if (referral_walks_count > MAX_NESTED_LINKS) {
- /*
- * BB: when we implement proper loop detection,
- * we will remove this check. But now we need it
- * to prevent an indefinite loop if 'DFS tree' is
- * misconfigured (i.e. has loops).
- */
+ if (count++ > MAX_NESTED_LINKS) {
rc = -ELOOP;
- goto mount_fail_check;
+ break;
}
- rc = expand_dfs_referral(xid, ses, volume_info, cifs_sb, true);
+ old_mountdata = cifs_sb->mountdata;
+ rc = expand_dfs_referral(xid, tcon->ses, vol, cifs_sb,
+ true);
+ if (rc)
+ break;
- if (!rc) {
- referral_walks_count++;
- goto try_mount_again;
+ if (cifs_sb->mountdata != old_mountdata) {
+ mount_put_conns(cifs_sb, xid, server, ses, tcon);
+ rc = mount_get_conns(vol, cifs_sb, &xid, &server, &ses,
+ &tcon);
+ }
+ if (rc) {
+ if (rc == -EACCES || rc == -EOPNOTSUPP || !server ||
+ !ses)
+ goto error;
}
- goto mount_fail_check;
-#else /* No DFS support, return error on mount */
- rc = -EOPNOTSUPP;
-#endif
}
if (rc)
- goto mount_fail_check;
-
- /* now, hang the tcon off of the superblock */
- tlink = kzalloc(sizeof *tlink, GFP_KERNEL);
- if (tlink == NULL) {
- rc = -ENOMEM;
- goto mount_fail_check;
- }
+ goto error;
- tlink->tl_uid = ses->linux_uid;
- tlink->tl_tcon = tcon;
- tlink->tl_time = jiffies;
- set_bit(TCON_LINK_MASTER, &tlink->tl_flags);
- set_bit(TCON_LINK_IN_TREE, &tlink->tl_flags);
+out:
+ free_xid(xid);
+ return mount_setup_tlink(cifs_sb, ses, tcon);
- cifs_sb->master_tlink = tlink;
- spin_lock(&cifs_sb->tlink_tree_lock);
- tlink_rb_insert(&cifs_sb->tlink_tree, tlink);
- spin_unlock(&cifs_sb->tlink_tree_lock);
+error:
+ mount_put_conns(cifs_sb, xid, server, ses, tcon);
+ return rc;
+}
+#else
+int cifs_mount(struct cifs_sb_info *cifs_sb, struct smb_vol *vol)
+{
+ int rc = 0;
+ unsigned int xid;
+ struct cifs_ses *ses;
+ struct cifs_tcon *tcon;
+ struct TCP_Server_Info *server;
- queue_delayed_work(cifsiod_wq, &cifs_sb->prune_tlinks,
- TLINK_IDLE_EXPIRE);
+ rc = mount_get_conns(vol, cifs_sb, &xid, &server, &ses, &tcon);
+ if (rc)
+ goto error;
-mount_fail_check:
- /* on error free sesinfo and tcon struct if needed */
- if (rc) {
- /* If find_unc succeeded then rc == 0 so we can not end */
- /* up accidentally freeing someone elses tcon struct */
- if (tcon)
- cifs_put_tcon(tcon);
- else if (ses)
- cifs_put_smb_ses(ses);
- else
- cifs_put_tcp_session(server, 0);
+ if (tcon) {
+ rc = is_path_remote(cifs_sb, vol, xid, server, tcon);
+ if (rc == -EREMOTE)
+ rc = -EOPNOTSUPP;
+ if (rc)
+ goto error;
}
-out:
free_xid(xid);
+
+ return mount_setup_tlink(cifs_sb, ses, tcon);
+
+error:
+ mount_put_conns(cifs_sb, xid, server, ses, tcon);
return rc;
}
+#endif
/*
* Issue a TREE_CONNECT request.
--
2.16.4