4 files changed, 78 insertions, 2 deletions

diff --git a/fs/fat/dir.c b/fs/fat/dir.c
index 165012ef363a..7a6f02caf286 100644
--- a/fs/fat/dir.c
+++ b/fs/fat/dir.c
@@ -964,6 +964,29 @@ int fat_scan(struct inode *dir, const unsigned char *name,
 }
 EXPORT_SYMBOL_GPL(fat_scan);
 
+/*
+ * Scans a directory for a given logstart.
+ * Returns an error code or zero.
+ */
+int fat_scan_logstart(struct inode *dir, int i_logstart,
+                      struct fat_slot_info *sinfo)
+{
+        struct super_block *sb = dir->i_sb;
+
+        sinfo->slot_off = 0;
+        sinfo->bh = NULL;
+        while (fat_get_short_entry(dir, &sinfo->slot_off, &sinfo->bh,
+                                   &sinfo->de) >= 0) {
+                if (fat_get_start(MSDOS_SB(sb), sinfo->de) == i_logstart) {
+                        sinfo->slot_off -= sizeof(*sinfo->de);
+                        sinfo->nr_slots = 1;
+                        sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
+                        return 0;
+                }
+        }
+        return -ENOENT;
+}
+
 static int __fat_remove_entries(struct inode *dir, loff_t pos, int nr_slots)
 {
         struct super_block *sb = dir->i_sb;
diff --git a/fs/fat/fat.h b/fs/fat/fat.h
index 413eaaf30ed5..21664fcf3616 100644
--- a/fs/fat/fat.h
+++ b/fs/fat/fat.h
@@ -296,6 +296,8 @@ extern int fat_dir_empty(struct inode *dir);
 extern int fat_subdirs(struct inode *dir);
 extern int fat_scan(struct inode *dir, const unsigned char *name,
                     struct fat_slot_info *sinfo);
+extern int fat_scan_logstart(struct inode *dir, int i_logstart,
+                             struct fat_slot_info *sinfo);
 extern int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh,
                                 struct msdos_dir_entry **de);
 extern int fat_alloc_new_dir(struct inode *dir, struct timespec *ts);
@@ -373,6 +375,7 @@ extern struct inode *fat_build_inode(struct super_block *sb,
 extern int fat_sync_inode(struct inode *inode);
 extern int fat_fill_super(struct super_block *sb, void *data, int silent,
                           int isvfat, void (*setup)(struct super_block *));
+extern int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de);
 
 extern int fat_flush_inodes(struct super_block *sb, struct inode *i1,
                             struct inode *i2);
diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index 971ba7d549da..4ff901632b26 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -384,7 +384,7 @@ static int fat_calc_dir_size(struct inode *inode)
 }
 
 /* doesn't deal with root inode */
-static int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
+int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
 {
         struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
         int error;
diff --git a/fs/fat/nfs.c b/fs/fat/nfs.c
index 0748196889b2..93e14933dcb6 100644
--- a/fs/fat/nfs.c
+++ b/fs/fat/nfs.c
@@ -216,6 +216,53 @@ static struct dentry *fat_fh_to_parent_nostale(struct super_block *sb,
 }
 
 /*
+ * Rebuild the parent for a directory that is not connected
+ *  to the filesystem root
+ */
+static
+struct inode *fat_rebuild_parent(struct super_block *sb, int parent_logstart)
+{
+        int search_clus, clus_to_match;
+        struct msdos_dir_entry *de;
+        struct inode *parent = NULL;
+        struct inode *dummy_grand_parent = NULL;
+        struct fat_slot_info sinfo;
+        struct msdos_sb_info *sbi = MSDOS_SB(sb);
+        sector_t blknr = fat_clus_to_blknr(sbi, parent_logstart);
+        struct buffer_head *parent_bh = sb_bread(sb, blknr);
+        if (!parent_bh) {
+                fat_msg(sb, KERN_ERR,
+                        "unable to read cluster of parent directory");
+                return NULL;
+        }
+
+        de = (struct msdos_dir_entry *) parent_bh->b_data;
+        clus_to_match = fat_get_start(sbi, &de[0]);
+        search_clus = fat_get_start(sbi, &de[1]);
+
+        dummy_grand_parent = fat_dget(sb, search_clus);
+        if (!dummy_grand_parent) {
+                dummy_grand_parent = new_inode(sb);
+                if (!dummy_grand_parent) {
+                        brelse(parent_bh);
+                        return parent;
+                }
+
+                dummy_grand_parent->i_ino = iunique(sb, MSDOS_ROOT_INO);
+                fat_fill_inode(dummy_grand_parent, &de[1]);
+                MSDOS_I(dummy_grand_parent)->i_pos = -1;
+        }
+
+        if (!fat_scan_logstart(dummy_grand_parent, clus_to_match, &sinfo))
+                parent = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
+
+        brelse(parent_bh);
+        iput(dummy_grand_parent);
+
+        return parent;
+}
+
+/*
  * Find the parent for a directory that is not currently connected to
  * the filesystem root.
  *
@@ -227,10 +274,13 @@ static struct dentry *fat_get_parent(struct dentry *child_dir)
         struct buffer_head *bh = NULL;
         struct msdos_dir_entry *de;
         struct inode *parent_inode = NULL;
+        struct msdos_sb_info *sbi = MSDOS_SB(sb);
 
         if (!fat_get_dotdot_entry(child_dir->d_inode, &bh, &de)) {
-                int parent_logstart = fat_get_start(MSDOS_SB(sb), de);
+                int parent_logstart = fat_get_start(sbi, de);
                 parent_inode = fat_dget(sb, parent_logstart);
+                if (!parent_inode && sbi->options.nfs == FAT_NFS_NOSTALE_RO)
+                        parent_inode = fat_rebuild_parent(sb, parent_logstart);
         }
         brelse(bh);