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>
diff --git a/fs/nilfs2/namei.c b/fs/nilfs2/namei.c
index 1110d56..a65f465 100644
--- 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)
{
@@ -77,23 +81,6 @@
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,
- NILFS_I(child->d_inode)->i_root, 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
@@ -469,6 +456,115 @@
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,
@@ -493,3 +589,10 @@
.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,
+};