diff options
Diffstat (limited to 'fs/cifs/cifs_dfs_ref.c')
| -rw-r--r-- | fs/cifs/cifs_dfs_ref.c | 377 |
1 files changed, 377 insertions, 0 deletions
diff --git a/fs/cifs/cifs_dfs_ref.c b/fs/cifs/cifs_dfs_ref.c new file mode 100644 index 00000000000..413ee2349d1 --- /dev/null +++ b/fs/cifs/cifs_dfs_ref.c @@ -0,0 +1,377 @@ +/* + * Contains the CIFS DFS referral mounting routines used for handling + * traversal via DFS junction point + * + * Copyright (c) 2007 Igor Mammedov + * Copyright (C) International Business Machines Corp., 2008 + * Author(s): Igor Mammedov (niallain@gmail.com) + * Steve French (sfrench@us.ibm.com) + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#include <linux/dcache.h> +#include <linux/mount.h> +#include <linux/namei.h> +#include <linux/vfs.h> +#include <linux/fs.h> +#include "cifsglob.h" +#include "cifsproto.h" +#include "cifsfs.h" +#include "dns_resolve.h" +#include "cifs_debug.h" + +LIST_HEAD(cifs_dfs_automount_list); + +/* + * DFS functions +*/ + +void dfs_shrink_umount_helper(struct vfsmount *vfsmnt) +{ + mark_mounts_for_expiry(&cifs_dfs_automount_list); + mark_mounts_for_expiry(&cifs_dfs_automount_list); + shrink_submounts(vfsmnt, &cifs_dfs_automount_list); +} + +/** + * cifs_get_share_name - extracts share name from UNC + * @node_name: pointer to UNC string + * + * Extracts sharename form full UNC. + * i.e. strips from UNC trailing path that is not part of share + * name and fixup missing '\' in the begining of DFS node refferal + * if neccessary. + * Returns pointer to share name on success or NULL on error. + * Caller is responsible for freeing returned string. + */ +static char *cifs_get_share_name(const char *node_name) +{ + int len; + char *UNC; + char *pSep; + + len = strlen(node_name); + UNC = kmalloc(len+2 /*for term null and additional \ if it's missed */, + GFP_KERNEL); + if (!UNC) + return NULL; + + /* get share name and server name */ + if (node_name[1] != '\\') { + UNC[0] = '\\'; + strncpy(UNC+1, node_name, len); + len++; + UNC[len] = 0; + } else { + strncpy(UNC, node_name, len); + UNC[len] = 0; + } + + /* find server name end */ + pSep = memchr(UNC+2, '\\', len-2); + if (!pSep) { + cERROR(1, ("%s: no server name end in node name: %s", + __FUNCTION__, node_name)); + kfree(UNC); + return NULL; + } + + /* find sharename end */ + pSep++; + pSep = memchr(UNC+(pSep-UNC), '\\', len-(pSep-UNC)); + if (!pSep) { + cERROR(1, ("%s:2 cant find share name in node name: %s", + __FUNCTION__, node_name)); + kfree(UNC); + return NULL; + } + /* trim path up to sharename end + * * now we have share name in UNC */ + *pSep = 0; + + return UNC; +} + + +/** + * compose_mount_options - creates mount options for refferral + * @sb_mountdata: parent/root DFS mount options (template) + * @ref_unc: refferral server UNC + * @devname: pointer for saving device name + * + * creates mount options for submount based on template options sb_mountdata + * and replacing unc,ip,prefixpath options with ones we've got form ref_unc. + * + * Returns: pointer to new mount options or ERR_PTR. + * Caller is responcible for freeing retunrned value if it is not error. + */ +static char *compose_mount_options(const char *sb_mountdata, + const char *ref_unc, + char **devname) +{ + int rc; + char *mountdata; + int md_len; + char *tkn_e; + char *srvIP = NULL; + char sep = ','; + int off, noff; + + if (sb_mountdata == NULL) + return ERR_PTR(-EINVAL); + + *devname = cifs_get_share_name(ref_unc); + rc = dns_resolve_server_name_to_ip(*devname, &srvIP); + if (rc != 0) { + cERROR(1, ("%s: Failed to resolve server part of %s to IP", + __FUNCTION__, *devname)); + mountdata = ERR_PTR(rc); + goto compose_mount_options_out; + } + md_len = strlen(sb_mountdata) + strlen(srvIP) + strlen(ref_unc) + 3; + mountdata = kzalloc(md_len+1, GFP_KERNEL); + if (mountdata == NULL) { + mountdata = ERR_PTR(-ENOMEM); + goto compose_mount_options_out; + } + + /* copy all options except of unc,ip,prefixpath */ + off = 0; + if (strncmp(sb_mountdata, "sep=", 4) == 0) { + sep = sb_mountdata[4]; + strncpy(mountdata, sb_mountdata, 5); + off += 5; + } + while ((tkn_e = strchr(sb_mountdata+off, sep))) { + noff = (tkn_e - (sb_mountdata+off)) + 1; + if (strnicmp(sb_mountdata+off, "unc=", 4) == 0) { + off += noff; + continue; + } + if (strnicmp(sb_mountdata+off, "ip=", 3) == 0) { + off += noff; + continue; + } + if (strnicmp(sb_mountdata+off, "prefixpath=", 3) == 0) { + off += noff; + continue; + } + strncat(mountdata, sb_mountdata+off, noff); + off += noff; + } + strcat(mountdata, sb_mountdata+off); + mountdata[md_len] = '\0'; + + /* copy new IP and ref share name */ + strcat(mountdata, ",ip="); + strcat(mountdata, srvIP); + strcat(mountdata, ",unc="); + strcat(mountdata, *devname); + + /* find & copy prefixpath */ + tkn_e = strchr(ref_unc+2, '\\'); + if (tkn_e) { + tkn_e = strchr(tkn_e+1, '\\'); + if (tkn_e) { + strcat(mountdata, ",prefixpath="); + strcat(mountdata, tkn_e); + } + } + + /*cFYI(1,("%s: parent mountdata: %s", __FUNCTION__,sb_mountdata));*/ + /*cFYI(1, ("%s: submount mountdata: %s", __FUNCTION__, mountdata ));*/ + +compose_mount_options_out: + kfree(srvIP); + return mountdata; +} + + +static struct vfsmount *cifs_dfs_do_refmount(const struct vfsmount *mnt_parent, + struct dentry *dentry, char *ref_unc) +{ + struct cifs_sb_info *cifs_sb; + struct vfsmount *mnt; + char *mountdata; + char *devname = NULL; + + cifs_sb = CIFS_SB(dentry->d_inode->i_sb); + mountdata = compose_mount_options(cifs_sb->mountdata, + ref_unc, &devname); + + if (IS_ERR(mountdata)) + return (struct vfsmount *)mountdata; + + mnt = vfs_kern_mount(&cifs_fs_type, 0, devname, mountdata); + kfree(mountdata); + kfree(devname); + return mnt; + +} + +static char *build_full_dfs_path_from_dentry(struct dentry *dentry) +{ + char *full_path = NULL; + char *search_path; + char *tmp_path; + size_t l_max_len; + struct cifs_sb_info *cifs_sb; + + if (dentry->d_inode == NULL) + return NULL; + + cifs_sb = CIFS_SB(dentry->d_inode->i_sb); + + if (cifs_sb->tcon == NULL) + return NULL; + + search_path = build_path_from_dentry(dentry); + if (search_path == NULL) + return NULL; + + if (cifs_sb->tcon->Flags & SMB_SHARE_IS_IN_DFS) { + /* we should use full path name to correct working with DFS */ + l_max_len = strnlen(cifs_sb->tcon->treeName, MAX_TREE_SIZE+1) + + strnlen(search_path, MAX_PATHCONF) + 1; + tmp_path = kmalloc(l_max_len, GFP_KERNEL); + if (tmp_path == NULL) { + kfree(search_path); + return NULL; + } + strncpy(tmp_path, cifs_sb->tcon->treeName, l_max_len); + strcat(tmp_path, search_path); + tmp_path[l_max_len-1] = 0; + full_path = tmp_path; + kfree(search_path); + } else { + full_path = search_path; + } + return full_path; +} + +static int add_mount_helper(struct vfsmount *newmnt, struct nameidata *nd, + struct list_head *mntlist) +{ + /* stolen from afs code */ + int err; + + mntget(newmnt); + err = do_add_mount(newmnt, nd, nd->mnt->mnt_flags, mntlist); + switch (err) { + case 0: + dput(nd->dentry); + mntput(nd->mnt); + nd->mnt = newmnt; + nd->dentry = dget(newmnt->mnt_root); + break; + case -EBUSY: + /* someone else made a mount here whilst we were busy */ + while (d_mountpoint(nd->dentry) && + follow_down(&nd->mnt, &nd->dentry)) + ; + err = 0; + default: + mntput(newmnt); + break; + } + return err; +} + +static void dump_referral(const struct dfs_info3_param *ref) +{ + cFYI(1, ("DFS: ref path: %s", ref->path_name)); + cFYI(1, ("DFS: node path: %s", ref->node_name)); + cFYI(1, ("DFS: fl: %hd, srv_type: %hd", ref->flags, ref->server_type)); + cFYI(1, ("DFS: ref_flags: %hd, path_consumed: %hd", ref->ref_flag, + ref->PathConsumed)); +} + + +static void* +cifs_dfs_follow_mountpoint(struct dentry *dentry, struct nameidata *nd) +{ + struct dfs_info3_param *referrals = NULL; + unsigned int num_referrals = 0; + struct cifs_sb_info *cifs_sb; + struct cifsSesInfo *ses; + char *full_path = NULL; + int xid, i; + int rc = 0; + struct vfsmount *mnt = ERR_PTR(-ENOENT); + + cFYI(1, ("in %s", __FUNCTION__)); + BUG_ON(IS_ROOT(dentry)); + + xid = GetXid(); + + dput(nd->dentry); + nd->dentry = dget(dentry); + + cifs_sb = CIFS_SB(dentry->d_inode->i_sb); + ses = cifs_sb->tcon->ses; + + if (!ses) { + rc = -EINVAL; + goto out_err; + } + + full_path = build_full_dfs_path_from_dentry(dentry); + if (full_path == NULL) { + rc = -ENOMEM; + goto out_err; + } + + rc = get_dfs_path(xid, ses , full_path, cifs_sb->local_nls, + &num_referrals, &referrals, + cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR); + + for (i = 0; i < num_referrals; i++) { + dump_referral(referrals+i); + /* connect to a storage node */ + if (referrals[i].flags & DFSREF_STORAGE_SERVER) { + int len; + len = strlen(referrals[i].node_name); + if (len < 2) { + cERROR(1, ("%s: Net Address path too short: %s", + __FUNCTION__, referrals[i].node_name)); + rc = -EINVAL; + goto out_err; + } + mnt = cifs_dfs_do_refmount(nd->mnt, nd->dentry, + referrals[i].node_name); + cFYI(1, ("%s: cifs_dfs_do_refmount:%s , mnt:%p", + __FUNCTION__, + referrals[i].node_name, mnt)); + + /* complete mount procedure if we accured submount */ + if (!IS_ERR(mnt)) + break; + } + } + + /* we need it cause for() above could exit without valid submount */ + rc = PTR_ERR(mnt); + if (IS_ERR(mnt)) + goto out_err; + + nd->mnt->mnt_flags |= MNT_SHRINKABLE; + rc = add_mount_helper(mnt, nd, &cifs_dfs_automount_list); + +out: + FreeXid(xid); + free_dfs_info_array(referrals, num_referrals); + kfree(full_path); + cFYI(1, ("leaving %s" , __FUNCTION__)); + return ERR_PTR(rc); +out_err: + path_release(nd); + goto out; +} + +struct inode_operations cifs_dfs_referral_inode_operations = { + .follow_link = cifs_dfs_follow_mountpoint, +}; + |