nilfs2: make snapshots in checkpoint tree exportable

[pandora-kernel.git] / fs / nilfs2 / namei.c

diff --git a/fs/nilfs2/namei.c b/fs/nilfs2/namei.c
index ad6ed2c..a65f465 100644 (file)
--- a/fs/nilfs2/namei.c
+++ b/fs/nilfs2/namei.c
@@ -40,7 +40,11 @@
 
 #include <linux/pagemap.h>
 #include "nilfs.h"
+#include "export.h"
 
+#define NILFS_FID_SIZE_NON_CONNECTABLE \
+       (offsetof(struct nilfs_fid, parent_gen) / 4)
+#define NILFS_FID_SIZE_CONNECTABLE     (sizeof(struct nilfs_fid) / 4)
 
 static inline int nilfs_add_nondir(struct dentry *dentry, struct inode *inode)
 {
@@ -70,29 +74,13 @@ nilfs_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
        ino = nilfs_inode_by_name(dir, &dentry->d_name);
        inode = NULL;
        if (ino) {
-               inode = nilfs_iget(dir->i_sb, ino);
+               inode = nilfs_iget(dir->i_sb, NILFS_I(dir)->i_root, ino);
                if (IS_ERR(inode))
                        return ERR_CAST(inode);
        }
        return d_splice_alias(inode, dentry);
 }
 
-struct dentry *nilfs_get_parent(struct dentry *child)
-{
-       unsigned long ino;
-       struct inode *inode;
-       struct qstr dotdot = {.name = "..", .len = 2};
-
-       ino = nilfs_inode_by_name(child->d_inode, &dotdot);
-       if (!ino)
-               return ERR_PTR(-ENOENT);
-
-       inode = nilfs_iget(child->d_inode->i_sb, ino);
-       if (IS_ERR(inode))
-               return ERR_CAST(inode);
-       return d_obtain_alias(inode);
-}
-
 /*
  * By the time this is called, we already have created
  * the directory cache entry for the new file, but it
@@ -468,6 +456,115 @@ out:
        return err;
 }
 
+/*
+ * Export operations
+ */
+static struct dentry *nilfs_get_parent(struct dentry *child)
+{
+       unsigned long ino;
+       struct inode *inode;
+       struct qstr dotdot = {.name = "..", .len = 2};
+       struct nilfs_root *root;
+
+       ino = nilfs_inode_by_name(child->d_inode, &dotdot);
+       if (!ino)
+               return ERR_PTR(-ENOENT);
+
+       root = NILFS_I(child->d_inode)->i_root;
+
+       inode = nilfs_iget(child->d_inode->i_sb, root, ino);
+       if (IS_ERR(inode))
+               return ERR_CAST(inode);
+
+       return d_obtain_alias(inode);
+}
+
+static struct dentry *nilfs_get_dentry(struct super_block *sb, u64 cno,
+                                      u64 ino, u32 gen)
+{
+       struct nilfs_root *root;
+       struct inode *inode;
+
+       if (ino < NILFS_FIRST_INO(sb) && ino != NILFS_ROOT_INO)
+               return ERR_PTR(-ESTALE);
+
+       root = nilfs_lookup_root(NILFS_SB(sb)->s_nilfs, cno);
+       if (!root)
+               return ERR_PTR(-ESTALE);
+
+       inode = nilfs_iget(sb, root, ino);
+       nilfs_put_root(root);
+
+       if (IS_ERR(inode))
+               return ERR_CAST(inode);
+       if (gen && inode->i_generation != gen) {
+               iput(inode);
+               return ERR_PTR(-ESTALE);
+       }
+       return d_obtain_alias(inode);
+}
+
+static struct dentry *nilfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
+                                        int fh_len, int fh_type)
+{
+       struct nilfs_fid *fid = (struct nilfs_fid *)fh;
+
+       if ((fh_len != NILFS_FID_SIZE_NON_CONNECTABLE &&
+            fh_len != NILFS_FID_SIZE_CONNECTABLE) ||
+           (fh_type != FILEID_NILFS_WITH_PARENT &&
+            fh_type != FILEID_NILFS_WITHOUT_PARENT))
+               return NULL;
+
+       return nilfs_get_dentry(sb, fid->cno, fid->ino, fid->gen);
+}
+
+static struct dentry *nilfs_fh_to_parent(struct super_block *sb, struct fid *fh,
+                                        int fh_len, int fh_type)
+{
+       struct nilfs_fid *fid = (struct nilfs_fid *)fh;
+
+       if (fh_len != NILFS_FID_SIZE_CONNECTABLE ||
+           fh_type != FILEID_NILFS_WITH_PARENT)
+               return NULL;
+
+       return nilfs_get_dentry(sb, fid->cno, fid->parent_ino, fid->parent_gen);
+}
+
+static int nilfs_encode_fh(struct dentry *dentry, __u32 *fh, int *lenp,
+                          int connectable)
+{
+       struct nilfs_fid *fid = (struct nilfs_fid *)fh;
+       struct inode *inode = dentry->d_inode;
+       struct nilfs_root *root = NILFS_I(inode)->i_root;
+       int type;
+
+       if (*lenp < NILFS_FID_SIZE_NON_CONNECTABLE ||
+           (connectable && *lenp < NILFS_FID_SIZE_CONNECTABLE))
+               return 255;
+
+       fid->cno = root->cno;
+       fid->ino = inode->i_ino;
+       fid->gen = inode->i_generation;
+
+       if (connectable && !S_ISDIR(inode->i_mode)) {
+               struct inode *parent;
+
+               spin_lock(&dentry->d_lock);
+               parent = dentry->d_parent->d_inode;
+               fid->parent_ino = parent->i_ino;
+               fid->parent_gen = parent->i_generation;
+               spin_unlock(&dentry->d_lock);
+
+               type = FILEID_NILFS_WITH_PARENT;
+               *lenp = NILFS_FID_SIZE_CONNECTABLE;
+       } else {
+               type = FILEID_NILFS_WITHOUT_PARENT;
+               *lenp = NILFS_FID_SIZE_NON_CONNECTABLE;
+       }
+
+       return type;
+}
+
 const struct inode_operations nilfs_dir_inode_operations = {
        .create         = nilfs_create,
        .lookup         = nilfs_lookup,
@@ -492,3 +589,10 @@ const struct inode_operations nilfs_symlink_inode_operations = {
        .follow_link    = page_follow_link_light,
        .put_link       = page_put_link,
 };
+
+const struct export_operations nilfs_export_ops = {
+       .encode_fh = nilfs_encode_fh,
+       .fh_to_dentry = nilfs_fh_to_dentry,
+       .fh_to_parent = nilfs_fh_to_parent,
+       .get_parent = nilfs_get_parent,
+};