Merge git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6

* git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6:
  [NFS] Set CONFIG_KEYS when CONFIG_NFS_USE_KERNEL_DNS is set
  AFS: Implement an autocell mount capability [ver #2]
  DNS: If the DNS server returns an error, allow that to be cached [ver #2]
  NFS: Use kernel DNS resolver [ver #2]
  cifs: update README to include details about 'fsc' option

fs/afs/cell.c

@@ -31,21 +31,20 @@ static struct afs_cell *afs_cell_root;
  * allocate a cell record and fill in its name, VL server address list and
  * allocate an anonymous key
  */
-static struct afs_cell *afs_cell_alloc(const char *name, char *vllist)
+static struct afs_cell *afs_cell_alloc(const char *name, unsigned namelen,
+				       char *vllist)
 {
 	struct afs_cell *cell;
 	struct key *key;
-	size_t namelen;
 	char keyname[4 + AFS_MAXCELLNAME + 1], *cp, *dp, *next;
 	char  *dvllist = NULL, *_vllist = NULL;
 	char  delimiter = ':';
 	int ret;
 
-	_enter("%s,%s", name, vllist);
+	_enter("%*.*s,%s", namelen, namelen, name ?: "", vllist);
 
 	BUG_ON(!name); /* TODO: want to look up "this cell" in the cache */
 
-	namelen = strlen(name);
 	if (namelen > AFS_MAXCELLNAME) {
 		_leave(" = -ENAMETOOLONG");
 		return ERR_PTR(-ENAMETOOLONG);
@@ -73,6 +72,10 @@ static struct afs_cell *afs_cell_alloc(const char *name, char *vllist)
 	if (!vllist || strlen(vllist) < 7) {
 		ret = dns_query("afsdb", name, namelen, "ipv4", &dvllist, NULL);
 		if (ret < 0) {
+			if (ret == -ENODATA || ret == -EAGAIN || ret == -ENOKEY)
+				/* translate these errors into something
+				 * userspace might understand */
+				ret = -EDESTADDRREQ;
 			_leave(" = %d", ret);
 			return ERR_PTR(ret);
 		}
@@ -138,26 +141,29 @@ static struct afs_cell *afs_cell_alloc(const char *name, char *vllist)
 }
 
 /*
- * create a cell record
- * - "name" is the name of the cell
- * - "vllist" is a colon separated list of IP addresses in "a.b.c.d" format
+ * afs_cell_crate() - create a cell record
+ * @name:	is the name of the cell.
+ * @namsesz:	is the strlen of the cell name.
+ * @vllist:	is a colon separated list of IP addresses in "a.b.c.d" format.
+ * @retref:	is T to return the cell reference when the cell exists.
  */
-struct afs_cell *afs_cell_create(const char *name, char *vllist)
+struct afs_cell *afs_cell_create(const char *name, unsigned namesz,
+				 char *vllist, bool retref)
 {
 	struct afs_cell *cell;
 	int ret;
 
-	_enter("%s,%s", name, vllist);
+	_enter("%*.*s,%s", namesz, namesz, name ?: "", vllist);
 
 	down_write(&afs_cells_sem);
 	read_lock(&afs_cells_lock);
 	list_for_each_entry(cell, &afs_cells, link) {
-		if (strcasecmp(cell->name, name) == 0)
+		if (strncasecmp(cell->name, name, namesz) == 0)
 			goto duplicate_name;
 	}
 	read_unlock(&afs_cells_lock);
 
-	cell = afs_cell_alloc(name, vllist);
+	cell = afs_cell_alloc(name, namesz, vllist);
 	if (IS_ERR(cell)) {
 		_leave(" = %ld", PTR_ERR(cell));
 		up_write(&afs_cells_sem);
@@ -197,8 +203,18 @@ struct afs_cell *afs_cell_create(const char *name, char *vllist)
 	return ERR_PTR(ret);
 
 duplicate_name:
+	if (retref && !IS_ERR(cell))
+		afs_get_cell(cell);
+
 	read_unlock(&afs_cells_lock);
 	up_write(&afs_cells_sem);
+
+	if (retref) {
+		_leave(" = %p", cell);
+		return cell;
+	}
+
+	_leave(" = -EEXIST");
 	return ERR_PTR(-EEXIST);
 }
 
@@ -229,7 +245,7 @@ int afs_cell_init(char *rootcell)
 		*cp++ = 0;
 
 	/* allocate a cell record for the root cell */
-	new_root = afs_cell_create(rootcell, cp);
+	new_root = afs_cell_create(rootcell, strlen(rootcell), cp, false);
 	if (IS_ERR(new_root)) {
 		_leave(" = %ld", PTR_ERR(new_root));
 		return PTR_ERR(new_root);
@@ -249,11 +265,12 @@ int afs_cell_init(char *rootcell)
 /*
  * lookup a cell record
  */
-struct afs_cell *afs_cell_lookup(const char *name, unsigned namesz)
+struct afs_cell *afs_cell_lookup(const char *name, unsigned namesz,
+				 bool dns_cell)
 {
 	struct afs_cell *cell;
 
-	_enter("\"%*.*s\",", namesz, namesz, name ? name : "");
+	_enter("\"%*.*s\",", namesz, namesz, name ?: "");
 
 	down_read(&afs_cells_sem);
 	read_lock(&afs_cells_lock);
@@ -267,6 +284,8 @@ struct afs_cell *afs_cell_lookup(const char *name, unsigned namesz)
 			}
 		}
 		cell = ERR_PTR(-ENOENT);
+		if (dns_cell)
+			goto create_cell;
 	found:
 		;
 	} else {
@@ -289,6 +308,15 @@ struct afs_cell *afs_cell_lookup(const char *name, unsigned namesz)
 	up_read(&afs_cells_sem);
 	_leave(" = %p", cell);
 	return cell;
+
+create_cell:
+	read_unlock(&afs_cells_lock);
+	up_read(&afs_cells_sem);
+
+	cell = afs_cell_create(name, namesz, NULL, true);
+
+	_leave(" = %p", cell);
+	return cell;
 }
 
 #if 0

fs/afs/dir.c

@@ -476,6 +476,40 @@ static int afs_do_lookup(struct inode *dir, struct dentry *dentry,
 	return 0;
 }
 
+/*
+ * Try to auto mount the mountpoint with pseudo directory, if the autocell
+ * operation is setted.
+ */
+static struct inode *afs_try_auto_mntpt(
+	int ret, struct dentry *dentry, struct inode *dir, struct key *key,
+	struct afs_fid *fid)
+{
+	const char *devname = dentry->d_name.name;
+	struct afs_vnode *vnode = AFS_FS_I(dir);
+	struct inode *inode;
+
+	_enter("%d, %p{%s}, {%x:%u}, %p",
+	       ret, dentry, devname, vnode->fid.vid, vnode->fid.vnode, key);
+
+	if (ret != -ENOENT ||
+	    !test_bit(AFS_VNODE_AUTOCELL, &vnode->flags))
+		goto out;
+
+	inode = afs_iget_autocell(dir, devname, strlen(devname), key);
+	if (IS_ERR(inode)) {
+		ret = PTR_ERR(inode);
+		goto out;
+	}
+
+	*fid = AFS_FS_I(inode)->fid;
+	_leave("= %p", inode);
+	return inode;
+
+out:
+	_leave("= %d", ret);
+	return ERR_PTR(ret);
+}
+
 /*
  * look up an entry in a directory
  */
@@ -520,6 +554,13 @@ static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry,
 
 	ret = afs_do_lookup(dir, dentry, &fid, key);
 	if (ret < 0) {
+		inode = afs_try_auto_mntpt(ret, dentry, dir, key, &fid);
+		if (!IS_ERR(inode)) {
+			key_put(key);
+			goto success;
+		}
+
+		ret = PTR_ERR(inode);
 		key_put(key);
 		if (ret == -ENOENT) {
 			d_add(dentry, NULL);
@@ -539,6 +580,7 @@ static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry,
 		return ERR_CAST(inode);
 	}
 
+success:
 	dentry->d_op = &afs_fs_dentry_operations;
 
 	d_add(dentry, inode);
@@ -696,8 +738,9 @@ static int afs_d_delete(struct dentry *dentry)
 		goto zap;
 
 	if (dentry->d_inode &&
-	    test_bit(AFS_VNODE_DELETED, &AFS_FS_I(dentry->d_inode)->flags))
-			goto zap;
+	    (test_bit(AFS_VNODE_DELETED,   &AFS_FS_I(dentry->d_inode)->flags) ||
+	     test_bit(AFS_VNODE_PSEUDODIR, &AFS_FS_I(dentry->d_inode)->flags)))
+		goto zap;
 
 	_leave(" = 0 [keep]");
 	return 0;

fs/afs/inode.c

@@ -19,6 +19,8 @@
 #include <linux/fs.h>
 #include <linux/pagemap.h>
 #include <linux/sched.h>
+#include <linux/mount.h>
+#include <linux/namei.h>
 #include "internal.h"
 
 struct afs_iget_data {
@@ -101,6 +103,16 @@ static int afs_iget5_test(struct inode *inode, void *opaque)
 		inode->i_version == data->fid.unique;
 }
 
+/*
+ * iget5() comparator for inode created by autocell operations
+ *
+ * These pseudo inodes don't match anything.
+ */
+static int afs_iget5_autocell_test(struct inode *inode, void *opaque)
+{
+	return 0;
+}
+
 /*
  * iget5() inode initialiser
  */
@@ -117,6 +129,67 @@ static int afs_iget5_set(struct inode *inode, void *opaque)
 	return 0;
 }
 
+/*
+ * inode retrieval for autocell
+ */
+struct inode *afs_iget_autocell(struct inode *dir, const char *dev_name,
+				int namesz, struct key *key)
+{
+	struct afs_iget_data data;
+	struct afs_super_info *as;
+	struct afs_vnode *vnode;
+	struct super_block *sb;
+	struct inode *inode;
+	static atomic_t afs_autocell_ino;
+
+	_enter("{%x:%u},%*.*s,",
+	       AFS_FS_I(dir)->fid.vid, AFS_FS_I(dir)->fid.vnode,
+	       namesz, namesz, dev_name ?: "");
+
+	sb = dir->i_sb;
+	as = sb->s_fs_info;
+	data.volume = as->volume;
+	data.fid.vid = as->volume->vid;
+	data.fid.unique = 0;
+	data.fid.vnode = 0;
+
+	inode = iget5_locked(sb, atomic_inc_return(&afs_autocell_ino),
+			     afs_iget5_autocell_test, afs_iget5_set,
+			     &data);
+	if (!inode) {
+		_leave(" = -ENOMEM");
+		return ERR_PTR(-ENOMEM);
+	}
+
+	_debug("GOT INODE %p { ino=%lu, vl=%x, vn=%x, u=%x }",
+	       inode, inode->i_ino, data.fid.vid, data.fid.vnode,
+	       data.fid.unique);
+
+	vnode = AFS_FS_I(inode);
+
+	/* there shouldn't be an existing inode */
+	BUG_ON(!(inode->i_state & I_NEW));
+
+	inode->i_size		= 0;
+	inode->i_mode		= S_IFDIR | S_IRUGO | S_IXUGO;
+	inode->i_op		= &afs_autocell_inode_operations;
+	inode->i_nlink		= 2;
+	inode->i_uid		= 0;
+	inode->i_gid		= 0;
+	inode->i_ctime.tv_sec	= get_seconds();
+	inode->i_ctime.tv_nsec	= 0;
+	inode->i_atime		= inode->i_mtime = inode->i_ctime;
+	inode->i_blocks		= 0;
+	inode->i_version	= 0;
+	inode->i_generation	= 0;
+
+	set_bit(AFS_VNODE_PSEUDODIR, &vnode->flags);
+	inode->i_flags |= S_NOATIME;
+	unlock_new_inode(inode);
+	_leave(" = %p", inode);
+	return inode;
+}
+
 /*
  * inode retrieval
  */
@@ -313,6 +386,19 @@ int afs_getattr(struct vfsmount *mnt, struct dentry *dentry,
 	return 0;
 }
 
+/*
+ * discard an AFS inode
+ */
+int afs_drop_inode(struct inode *inode)
+{
+	_enter("");
+
+	if (test_bit(AFS_VNODE_PSEUDODIR, &AFS_FS_I(inode)->flags))
+		return generic_delete_inode(inode);
+	else
+		return generic_drop_inode(inode);
+}
+
 /*
  * clear an AFS inode
  */

fs/afs/internal.h

@@ -42,6 +42,7 @@ typedef enum {
 struct afs_mount_params {
 	bool			rwpath;		/* T if the parent should be considered R/W */
 	bool			force;		/* T to force cell type */
+	bool			autocell;	/* T if set auto mount operation */
 	afs_voltype_t		type;		/* type of volume requested */
 	int			volnamesz;	/* size of volume name */
 	const char		*volname;	/* name of volume to mount */
@@ -358,6 +359,8 @@ struct afs_vnode {
 #define AFS_VNODE_READLOCKED	7		/* set if vnode is read-locked on the server */
 #define AFS_VNODE_WRITELOCKED	8		/* set if vnode is write-locked on the server */
 #define AFS_VNODE_UNLOCKING	9		/* set if vnode is being unlocked on the server */
+#define AFS_VNODE_AUTOCELL	10		/* set if Vnode is an auto mount point */
+#define AFS_VNODE_PSEUDODIR	11		/* set if Vnode is a pseudo directory */
 
 	long			acl_order;	/* ACL check count (callback break count) */
 
@@ -468,8 +471,8 @@ extern struct list_head afs_proc_cells;
 
 #define afs_get_cell(C) do { atomic_inc(&(C)->usage); } while(0)
 extern int afs_cell_init(char *);
-extern struct afs_cell *afs_cell_create(const char *, char *);
-extern struct afs_cell *afs_cell_lookup(const char *, unsigned);
+extern struct afs_cell *afs_cell_create(const char *, unsigned, char *, bool);
+extern struct afs_cell *afs_cell_lookup(const char *, unsigned, bool);
 extern struct afs_cell *afs_grab_cell(struct afs_cell *);
 extern void afs_put_cell(struct afs_cell *);
 extern void afs_cell_purge(void);
@@ -558,6 +561,8 @@ extern int afs_fs_release_lock(struct afs_server *, struct key *,
 /*
  * inode.c
  */
+extern struct inode *afs_iget_autocell(struct inode *, const char *, int,
+				       struct key *);
 extern struct inode *afs_iget(struct super_block *, struct key *,
 			      struct afs_fid *, struct afs_file_status *,
 			      struct afs_callback *);
@@ -566,6 +571,7 @@ extern int afs_validate(struct afs_vnode *, struct key *);
 extern int afs_getattr(struct vfsmount *, struct dentry *, struct kstat *);
 extern int afs_setattr(struct dentry *, struct iattr *);
 extern void afs_evict_inode(struct inode *);
+extern int afs_drop_inode(struct inode *);
 
 /*
  * main.c
@@ -581,6 +587,7 @@ extern int afs_abort_to_error(u32);
  * mntpt.c
  */
 extern const struct inode_operations afs_mntpt_inode_operations;
+extern const struct inode_operations afs_autocell_inode_operations;
 extern const struct file_operations afs_mntpt_file_operations;
 
 extern int afs_mntpt_check_symlink(struct afs_vnode *, struct key *);