nilfs2: make snapshots in checkpoint tree exportable

The previous export operations cannot handle multiple versions of
a filesystem if they belong to the same sb instance.

This adds a new type of file handle and extends export operations so
that they can get the inode specified by a checkpoint number as well
as an inode number and a generation number.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

1 files changed, 1 insertions, 51 deletions

diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c
index a1c0e38a7706..adbf5826b837 100644
--- a/fs/nilfs2/super.c
+++ b/fs/nilfs2/super.c
@@ -48,10 +48,10 @@
 #include <linux/vfs.h>
 #include <linux/writeback.h>
 #include <linux/kobject.h>
-#include <linux/exportfs.h>
 #include <linux/seq_file.h>
 #include <linux/mount.h>
 #include "nilfs.h"
+#include "export.h"
 #include "mdt.h"
 #include "alloc.h"
 #include "btree.h"
@@ -556,56 +556,6 @@ static const struct super_operations nilfs_sops = {
         .show_options = nilfs_show_options
 };
 
-static struct inode *
-nilfs_nfs_get_inode(struct super_block *sb, u64 ino, u32 generation)
-{
-        struct inode *inode;
-        struct nilfs_root *root;
-
-        if (ino < NILFS_FIRST_INO(sb) && ino != NILFS_ROOT_INO &&
-            ino != NILFS_SKETCH_INO)
-                return ERR_PTR(-ESTALE);
-
-        root = nilfs_lookup_root(NILFS_SB(sb)->s_nilfs,
-                                 NILFS_CPTREE_CURRENT_CNO);
-        if (!root)
-                return ERR_PTR(-ESTALE);
-
-        /* new file handle type is required to export snapshots */
-        inode = nilfs_iget(sb, root, ino);
-        nilfs_put_root(root);
-        if (IS_ERR(inode))
-                return ERR_CAST(inode);
-        if (generation && inode->i_generation != generation) {
-                iput(inode);
-                return ERR_PTR(-ESTALE);
-        }
-
-        return inode;
-}
-
-static struct dentry *
-nilfs_fh_to_dentry(struct super_block *sb, struct fid *fid, int fh_len,
-                   int fh_type)
-{
-        return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
-                                    nilfs_nfs_get_inode);
-}
-
-static struct dentry *
-nilfs_fh_to_parent(struct super_block *sb, struct fid *fid, int fh_len,
-                   int fh_type)
-{
-        return generic_fh_to_parent(sb, fid, fh_len, fh_type,
-                                    nilfs_nfs_get_inode);
-}
-
-static const struct export_operations nilfs_export_ops = {
-        .fh_to_dentry = nilfs_fh_to_dentry,
-        .fh_to_parent = nilfs_fh_to_parent,
-        .get_parent = nilfs_get_parent,
-};
-
 enum {
         Opt_err_cont, Opt_err_panic, Opt_err_ro,
         Opt_barrier, Opt_nobarrier, Opt_snapshot, Opt_order, Opt_norecovery,