4 files changed, 78 insertions, 2 deletions

diff --git a/fs/fat/dir.c b/fs/fat/dir.c
index 165012ef363..7a6f02caf28 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 413eaaf30ed..21664fcf361 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 971ba7d549d..4ff901632b2 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 0748196889b..93e14933dcb 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);