aboutsummaryrefslogtreecommitdiffstats
path: root/fs/fat/nfs.c
diff options
context:
space:
mode:
Diffstat (limited to 'fs/fat/nfs.c')
-rw-r--r--fs/fat/nfs.c101
1 files changed, 101 insertions, 0 deletions
diff --git a/fs/fat/nfs.c b/fs/fat/nfs.c
new file mode 100644
index 00000000000..ef4b5faba87
--- /dev/null
+++ b/fs/fat/nfs.c
@@ -0,0 +1,101 @@
+/* fs/fat/nfs.c
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/exportfs.h>
+#include "fat.h"
+
+/**
+ * Look up a directory inode given its starting cluster.
+ */
+static struct inode *fat_dget(struct super_block *sb, int i_logstart)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ struct hlist_head *head;
+ struct hlist_node *_p;
+ struct msdos_inode_info *i;
+ struct inode *inode = NULL;
+
+ head = sbi->dir_hashtable + fat_dir_hash(i_logstart);
+ spin_lock(&sbi->dir_hash_lock);
+ hlist_for_each_entry(i, _p, head, i_dir_hash) {
+ BUG_ON(i->vfs_inode.i_sb != sb);
+ if (i->i_logstart != i_logstart)
+ continue;
+ inode = igrab(&i->vfs_inode);
+ if (inode)
+ break;
+ }
+ spin_unlock(&sbi->dir_hash_lock);
+ return inode;
+}
+
+static struct inode *fat_nfs_get_inode(struct super_block *sb,
+ u64 ino, u32 generation)
+{
+ struct inode *inode;
+
+ if ((ino < MSDOS_ROOT_INO) || (ino == MSDOS_FSINFO_INO))
+ return NULL;
+
+ inode = ilookup(sb, ino);
+ if (inode && generation && (inode->i_generation != generation)) {
+ iput(inode);
+ inode = NULL;
+ }
+
+ return inode;
+}
+
+/**
+ * Map a NFS file handle to a corresponding dentry.
+ * The dentry may or may not be connected to the filesystem root.
+ */
+struct dentry *fat_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,
+ fat_nfs_get_inode);
+}
+
+/*
+ * Find the parent for a file specified by NFS handle.
+ * This requires that the handle contain the i_ino of the parent.
+ */
+struct dentry *fat_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,
+ fat_nfs_get_inode);
+}
+
+/*
+ * Find the parent for a directory that is not currently connected to
+ * the filesystem root.
+ *
+ * On entry, the caller holds child_dir->d_inode->i_mutex.
+ */
+struct dentry *fat_get_parent(struct dentry *child_dir)
+{
+ struct super_block *sb = child_dir->d_sb;
+ struct buffer_head *bh = NULL;
+ struct msdos_dir_entry *de;
+ struct inode *parent_inode = NULL;
+
+ if (!fat_get_dotdot_entry(child_dir->d_inode, &bh, &de)) {
+ int parent_logstart = fat_get_start(MSDOS_SB(sb), de);
+ parent_inode = fat_dget(sb, parent_logstart);
+ }
+ brelse(bh);
+
+ return d_obtain_alias(parent_inode);
+}