Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6

1 files changed, 220 insertions, 219 deletions

diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c
index e98f6cd7200c..8adb32a9387a 100644
--- a/fs/exportfs/expfs.c
+++ b/fs/exportfs/expfs.c
@@ -1,15 +1,45 @@
 
+#include <linux/exportfs.h>
 #include <linux/fs.h>
 #include <linux/file.h>
 #include <linux/module.h>
+#include <linux/mount.h>
 #include <linux/namei.h>
 
-struct export_operations export_op_default;
+#define dprintk(fmt, args...) do{}while(0)
 
-#define CALL(ops,fun) ((ops->fun)?(ops->fun):export_op_default.fun)
 
-#define dprintk(fmt, args...) do{}while(0)
+static int get_name(struct dentry *dentry, char *name,
+                struct dentry *child);
+
+
+static struct dentry *exportfs_get_dentry(struct super_block *sb, void *obj)
+{
+        struct dentry *result = ERR_PTR(-ESTALE);
+
+        if (sb->s_export_op->get_dentry) {
+                result = sb->s_export_op->get_dentry(sb, obj);
+                if (!result)
+                        result = ERR_PTR(-ESTALE);
+        }
+
+        return result;
+}
+
+static int exportfs_get_name(struct dentry *dir, char *name,
+                struct dentry *child)
+{
+        struct export_operations *nop = dir->d_sb->s_export_op;
 
+        if (nop->get_name)
+                return nop->get_name(dir, name, child);
+        else
+                return get_name(dir, name, child);
+}
+
+/*
+ * Check if the dentry or any of it's aliases is acceptable.
+ */
 static struct dentry *
 find_acceptable_alias(struct dentry *result,
                 int (*acceptable)(void *context, struct dentry *dentry),
@@ -17,6 +47,9 @@ find_acceptable_alias(struct dentry *result,
 {
         struct dentry *dentry, *toput = NULL;
 
+        if (acceptable(context, result))
+                return result;
+
         spin_lock(&dcache_lock);
         list_for_each_entry(dentry, &result->d_inode->i_dentry, d_alias) {
                 dget_locked(dentry);
@@ -37,130 +70,50 @@ find_acceptable_alias(struct dentry *result,
         return NULL;
 }
 
-/**
- * find_exported_dentry - helper routine to implement export_operations->decode_fh
- * @sb:         The &super_block identifying the filesystem
- * @obj:        An opaque identifier of the object to be found - passed to
- *              get_inode
- * @parent:     An optional opqaue identifier of the parent of the object.
- * @acceptable: A function used to test possible &dentries to see if they are
- *              acceptable
- * @context:    A parameter to @acceptable so that it knows on what basis to
- *              judge.
- *
- * find_exported_dentry is the central helper routine to enable file systems
- * to provide the decode_fh() export_operation.  It's main task is to take
- * an &inode, find or create an appropriate &dentry structure, and possibly
- * splice this into the dcache in the correct place.
- *
- * The decode_fh() operation provided by the filesystem should call
- * find_exported_dentry() with the same parameters that it received except
- * that instead of the file handle fragment, pointers to opaque identifiers
- * for the object and optionally its parent are passed.  The default decode_fh
- * routine passes one pointer to the start of the filehandle fragment, and
- * one 8 bytes into the fragment.  It is expected that most filesystems will
- * take this approach, though the offset to the parent identifier may well be
- * different.
- *
- * find_exported_dentry() will call get_dentry to get an dentry pointer from
- * the file system.  If any &dentry in the d_alias list is acceptable, it will
- * be returned.  Otherwise find_exported_dentry() will attempt to splice a new
- * &dentry into the dcache using get_name() and get_parent() to find the
- * appropriate place.
+/*
+ * Find root of a disconnected subtree and return a reference to it.
  */
-
-struct dentry *
-find_exported_dentry(struct super_block *sb, void *obj, void *parent,
-                     int (*acceptable)(void *context, struct dentry *de),
-                     void *context)
+static struct dentry *
+find_disconnected_root(struct dentry *dentry)
 {
-        struct dentry *result = NULL;
-        struct dentry *target_dir;
-        int err;
-        struct export_operations *nops = sb->s_export_op;
-        struct dentry *alias;
-        int noprogress;
-        char nbuf[NAME_MAX+1];
-
-        /*
-         * Attempt to find the inode.
-         */
-        result = CALL(sb->s_export_op,get_dentry)(sb,obj);
-        err = -ESTALE;
-        if (result == NULL)
-                goto err_out;
-        if (IS_ERR(result)) {
-                err = PTR_ERR(result);
-                goto err_out;
+        dget(dentry);
+        spin_lock(&dentry->d_lock);
+        while (!IS_ROOT(dentry) &&
+               (dentry->d_parent->d_flags & DCACHE_DISCONNECTED)) {
+                struct dentry *parent = dentry->d_parent;
+                dget(parent);
+                spin_unlock(&dentry->d_lock);
+                dput(dentry);
+                dentry = parent;
+                spin_lock(&dentry->d_lock);
         }
-        if (S_ISDIR(result->d_inode->i_mode) &&
-            (result->d_flags & DCACHE_DISCONNECTED)) {
-                /* it is an unconnected directory, we must connect it */
-                ;
-        } else {
-                if (acceptable(context, result))
-                        return result;
-                if (S_ISDIR(result->d_inode->i_mode)) {
-                        err = -EACCES;
-                        goto err_result;
-                }
+        spin_unlock(&dentry->d_lock);
+        return dentry;
+}
 
-                alias = find_acceptable_alias(result, acceptable, context);
-                if (alias)
-                        return alias;
-        }                       
-
-        /* It's a directory, or we are required to confirm the file's
-         * location in the tree based on the parent information
-         */
-        dprintk("find_exported_dentry: need to look harder for %s/%d\n",sb->s_id,*(int*)obj);
-        if (S_ISDIR(result->d_inode->i_mode))
-                target_dir = dget(result);
-        else {
-                if (parent == NULL)
-                        goto err_result;
 
-                target_dir = CALL(sb->s_export_op,get_dentry)(sb,parent);
-                if (IS_ERR(target_dir))
-                        err = PTR_ERR(target_dir);
-                if (target_dir == NULL || IS_ERR(target_dir))
-                        goto err_result;
-        }
-        /*
-         * Now we need to make sure that target_dir is properly connected.
-         * It may already be, as the flag isn't always updated when connection
-         * happens.
-         * So, we walk up parent links until we find a connected directory,
-         * or we run out of directories.  Then we find the parent, find
-         * the name of the child in that parent, and do a lookup.
-         * This should connect the child into the parent
-         * We then repeat.
-         */
+/*
+ * Make sure target_dir is fully connected to the dentry tree.
+ *
+ * It may already be, as the flag isn't always updated when connection happens.
+ */
+static int
+reconnect_path(struct super_block *sb, struct dentry *target_dir)
+{
+        char nbuf[NAME_MAX+1];
+        int noprogress = 0;
+        int err = -ESTALE;
 
-        /* it is possible that a confused file system might not let us complete 
+        /*
+         * It is possible that a confused file system might not let us complete
          * the path to the root.  For example, if get_parent returns a directory
          * in which we cannot find a name for the child.  While this implies a
          * very sick filesystem we don't want it to cause knfsd to spin.  Hence
          * the noprogress counter.  If we go through the loop 10 times (2 is
          * probably enough) without getting anywhere, we just give up
          */
-        noprogress= 0;
         while (target_dir->d_flags & DCACHE_DISCONNECTED && noprogress++ < 10) {
-                struct dentry *pd = target_dir;
-
-                dget(pd);
-                spin_lock(&pd->d_lock);
-                while (!IS_ROOT(pd) &&
-                                (pd->d_parent->d_flags&DCACHE_DISCONNECTED)) {
-                        struct dentry *parent = pd->d_parent;
-
-                        dget(parent);
-                        spin_unlock(&pd->d_lock);
-                        dput(pd);
-                        pd = parent;
-                        spin_lock(&pd->d_lock);
-                }
-                spin_unlock(&pd->d_lock);
+                struct dentry *pd = find_disconnected_root(target_dir);
 
                 if (!IS_ROOT(pd)) {
                         /* must have found a connected parent - great */
@@ -175,29 +128,40 @@ find_exported_dentry(struct super_block *sb, void *obj, void *parent,
                         spin_unlock(&pd->d_lock);
                         noprogress = 0;
                 } else {
-                        /* we have hit the top of a disconnected path.  Try
-                         * to find parent and connect
-                         * note: racing with some other process renaming a
-                         * directory isn't much of a problem here.  If someone
-                         * renames the directory, it will end up properly
-                         * connected, which is what we want
+                        /*
+                         * We have hit the top of a disconnected path, try to
+                         * find parent and connect.
+                         *
+                         * Racing with some other process renaming a directory
+                         * isn't much of a problem here.  If someone renames
+                         * the directory, it will end up properly connected,
+                         * which is what we want
+                         *
+                         * Getting the parent can't be supported generically,
+                         * the locking is too icky.
+                         *
+                         * Instead we just return EACCES.  If server reboots
+                         * or inodes get flushed, you lose
                          */
-                        struct dentry *ppd;
+                        struct dentry *ppd = ERR_PTR(-EACCES);
                         struct dentry *npd;
 
                         mutex_lock(&pd->d_inode->i_mutex);
-                        ppd = CALL(nops,get_parent)(pd);
+                        if (sb->s_export_op->get_parent)
+                                ppd = sb->s_export_op->get_parent(pd);
                         mutex_unlock(&pd->d_inode->i_mutex);
 
                         if (IS_ERR(ppd)) {
                                 err = PTR_ERR(ppd);
-                                dprintk("find_exported_dentry: get_parent of %ld failed, err %d\n",
-                                        pd->d_inode->i_ino, err);
+                                dprintk("%s: get_parent of %ld failed, err %d\n",
+                                        __FUNCTION__, pd->d_inode->i_ino, err);
                                 dput(pd);
                                 break;
                         }
-                        dprintk("find_exported_dentry: find name of %lu in %lu\n", pd->d_inode->i_ino, ppd->d_inode->i_ino);
-                        err = CALL(nops,get_name)(ppd, nbuf, pd);
+
+                        dprintk("%s: find name of %lu in %lu\n", __FUNCTION__,
+                                pd->d_inode->i_ino, ppd->d_inode->i_ino);
+                        err = exportfs_get_name(ppd, nbuf, pd);
                         if (err) {
                                 dput(ppd);
                                 dput(pd);
@@ -208,13 +172,14 @@ find_exported_dentry(struct super_block *sb, void *obj, void *parent,
                                         continue;
                                 break;
                         }
-                        dprintk("find_exported_dentry: found name: %s\n", nbuf);
+                        dprintk("%s: found name: %s\n", __FUNCTION__, nbuf);
                         mutex_lock(&ppd->d_inode->i_mutex);
                         npd = lookup_one_len(nbuf, ppd, strlen(nbuf));
                         mutex_unlock(&ppd->d_inode->i_mutex);
                         if (IS_ERR(npd)) {
                                 err = PTR_ERR(npd);
-                                dprintk("find_exported_dentry: lookup failed: %d\n", err);
+                                dprintk("%s: lookup failed: %d\n",
+                                        __FUNCTION__, err);
                                 dput(ppd);
                                 dput(pd);
                                 break;
@@ -227,7 +192,7 @@ find_exported_dentry(struct super_block *sb, void *obj, void *parent,
                         if (npd == pd)
                                 noprogress = 0;
                         else
-                                printk("find_exported_dentry: npd != pd\n");
+                                printk("%s: npd != pd\n", __FUNCTION__);
                         dput(npd);
                         dput(ppd);
                         if (IS_ROOT(pd)) {
@@ -243,15 +208,101 @@ find_exported_dentry(struct super_block *sb, void *obj, void *parent,
                 /* something went wrong - oh-well */
                 if (!err)
                         err = -ESTALE;
-                goto err_target;
+                return err;
         }
-        /* if we weren't after a directory, have one more step to go */
-        if (result != target_dir) {
-                struct dentry *nresult;
-                err = CALL(nops,get_name)(target_dir, nbuf, result);
+
+        return 0;
+}
+
+/**
+ * find_exported_dentry - helper routine to implement export_operations->decode_fh
+ * @sb:         The &super_block identifying the filesystem
+ * @obj:        An opaque identifier of the object to be found - passed to
+ *              get_inode
+ * @parent:     An optional opqaue identifier of the parent of the object.
+ * @acceptable: A function used to test possible &dentries to see if they are
+ *              acceptable
+ * @context:    A parameter to @acceptable so that it knows on what basis to
+ *              judge.
+ *
+ * find_exported_dentry is the central helper routine to enable file systems
+ * to provide the decode_fh() export_operation.  It's main task is to take
+ * an &inode, find or create an appropriate &dentry structure, and possibly
+ * splice this into the dcache in the correct place.
+ *
+ * The decode_fh() operation provided by the filesystem should call
+ * find_exported_dentry() with the same parameters that it received except
+ * that instead of the file handle fragment, pointers to opaque identifiers
+ * for the object and optionally its parent are passed.  The default decode_fh
+ * routine passes one pointer to the start of the filehandle fragment, and
+ * one 8 bytes into the fragment.  It is expected that most filesystems will
+ * take this approach, though the offset to the parent identifier may well be
+ * different.
+ *
+ * find_exported_dentry() will call get_dentry to get an dentry pointer from
+ * the file system.  If any &dentry in the d_alias list is acceptable, it will
+ * be returned.  Otherwise find_exported_dentry() will attempt to splice a new
+ * &dentry into the dcache using get_name() and get_parent() to find the
+ * appropriate place.
+ */
+
+struct dentry *
+find_exported_dentry(struct super_block *sb, void *obj, void *parent,
+                     int (*acceptable)(void *context, struct dentry *de),
+                     void *context)
+{
+        struct dentry *result, *alias;
+        int err = -ESTALE;
+
+        /*
+         * Attempt to find the inode.
+         */
+        result = exportfs_get_dentry(sb, obj);
+        if (IS_ERR(result))
+                return result;
+
+        if (S_ISDIR(result->d_inode->i_mode)) {
+                if (!(result->d_flags & DCACHE_DISCONNECTED)) {
+                        if (acceptable(context, result))
+                                return result;
+                        err = -EACCES;
+                        goto err_result;
+                }
+
+                err = reconnect_path(sb, result);
+                if (err)
+                        goto err_result;
+        } else {
+                struct dentry *target_dir, *nresult;
+                char nbuf[NAME_MAX+1];
+
+                alias = find_acceptable_alias(result, acceptable, context);
+                if (alias)
+                        return alias;
+
+                if (parent == NULL)
+                        goto err_result;
+
+                target_dir = exportfs_get_dentry(sb,parent);
+                if (IS_ERR(target_dir)) {
+                        err = PTR_ERR(target_dir);
+                        goto err_result;
+                }
+
+                err = reconnect_path(sb, target_dir);
+                if (err) {
+                        dput(target_dir);
+                        goto err_result;
+                }
+
+                /*
+                 * As we weren't after a directory, have one more step to go.
+                 */
+                err = exportfs_get_name(target_dir, nbuf, result);
                 if (!err) {
                         mutex_lock(&target_dir->d_inode->i_mutex);
-                        nresult = lookup_one_len(nbuf, target_dir, strlen(nbuf));
+                        nresult = lookup_one_len(nbuf, target_dir,
+                                                 strlen(nbuf));
                         mutex_unlock(&target_dir->d_inode->i_mutex);
                         if (!IS_ERR(nresult)) {
                                 if (nresult->d_inode) {
@@ -261,11 +312,8 @@ find_exported_dentry(struct super_block *sb, void *obj, void *parent,
                                         dput(nresult);
                         }
                 }
+                dput(target_dir);
         }
-        dput(target_dir);
-        /* now result is properly connected, it is our best bet */
-        if (acceptable(context, result))
-                return result;
 
         alias = find_acceptable_alias(result, acceptable, context);
         if (alias)
@@ -275,32 +323,16 @@ find_exported_dentry(struct super_block *sb, void *obj, void *parent,
         dput(result);
         /* It might be justifiable to return ESTALE here,
          * but the filehandle at-least looks reasonable good
-         * and it just be a permission problem, so returning
+         * and it may just be a permission problem, so returning
          * -EACCESS is safer
          */
         return ERR_PTR(-EACCES);
 
- err_target:
-        dput(target_dir);
  err_result:
         dput(result);
- err_out:
         return ERR_PTR(err);
 }
 
-
-
-static struct dentry *get_parent(struct dentry *child)
-{
-        /* get_parent cannot be supported generically, the locking
-         * is too icky.
-         * instead, we just return EACCES.  If server reboots or inodes
-         * get flushed, you lose
-         */
-        return ERR_PTR(-EACCES);
-}
-
-
 struct getdents_callback {
         char *name;             /* name that was found. It already points to a
                                    buffer NAME_MAX+1 is size */
@@ -390,61 +422,6 @@ out:
         return error;
 }
 
-
-static struct dentry *export_iget(struct super_block *sb, unsigned long ino, __u32 generation)
-{
-
-        /* iget isn't really right if the inode is currently unallocated!!
-         * This should really all be done inside each filesystem
-         *
-         * ext2fs' read_inode has been strengthed to return a bad_inode if
-         * the inode had been deleted.
-         *
-         * Currently we don't know the generation for parent directory, so
-         * a generation of 0 means "accept any"
-         */
-        struct inode *inode;
-        struct dentry *result;
-        if (ino == 0)
-                return ERR_PTR(-ESTALE);
-        inode = iget(sb, ino);
-        if (inode == NULL)
-                return ERR_PTR(-ENOMEM);
-        if (is_bad_inode(inode)
-            || (generation && inode->i_generation != generation)
-                ) {
-                /* we didn't find the right inode.. */
-                dprintk("fh_verify: Inode %lu, Bad count: %d %d or version  %u %u\n",
-                        inode->i_ino,
-                        inode->i_nlink, atomic_read(&inode->i_count),
-                        inode->i_generation,
-                        generation);
-
-                iput(inode);
-                return ERR_PTR(-ESTALE);
-        }
-        /* now to find a dentry.
-         * If possible, get a well-connected one
-         */
-        result = d_alloc_anon(inode);
-        if (!result) {
-                iput(inode);
-                return ERR_PTR(-ENOMEM);
-        }
-        return result;
-}
-
-
-static struct dentry *get_object(struct super_block *sb, void *vobjp)
-{
-        __u32 *objp = vobjp;
-        unsigned long ino = objp[0];
-        __u32 generation = objp[1];
-
-        return export_iget(sb, ino, generation);
-}
-
-
 /**
  * export_encode_fh - default export_operations->encode_fh function
  * @dentry:  the dentry to encode
@@ -517,16 +494,40 @@ static struct dentry *export_decode_fh(struct super_block *sb, __u32 *fh, int fh
                                    acceptable, context);
 }
 
-struct export_operations export_op_default = {
-        .decode_fh      = export_decode_fh,
-        .encode_fh      = export_encode_fh,
+int exportfs_encode_fh(struct dentry *dentry, __u32 *fh, int *max_len,
+                int connectable)
+{
+        struct export_operations *nop = dentry->d_sb->s_export_op;
+        int error;
+
+        if (nop->encode_fh)
+                error = nop->encode_fh(dentry, fh, max_len, connectable);
+        else
+                error = export_encode_fh(dentry, fh, max_len, connectable);
 
-        .get_name       = get_name,
-        .get_parent     = get_parent,
-        .get_dentry     = get_object,
-};
+        return error;
+}
+EXPORT_SYMBOL_GPL(exportfs_encode_fh);
+
+struct dentry *exportfs_decode_fh(struct vfsmount *mnt, __u32 *fh, int fh_len,
+                int fileid_type, int (*acceptable)(void *, struct dentry *),
+                void *context)
+{
+        struct export_operations *nop = mnt->mnt_sb->s_export_op;
+        struct dentry *result;
+
+        if (nop->decode_fh) {
+                result = nop->decode_fh(mnt->mnt_sb, fh, fh_len, fileid_type,
+                        acceptable, context);
+        } else {
+                result = export_decode_fh(mnt->mnt_sb, fh, fh_len, fileid_type,
+                        acceptable, context);
+        }
+
+        return result;
+}
+EXPORT_SYMBOL_GPL(exportfs_decode_fh);
 
-EXPORT_SYMBOL(export_op_default);
 EXPORT_SYMBOL(find_exported_dentry);
 
 MODULE_LICENSE("GPL");