nfs: disintegrate UAPI for nfs

This is to complete part of the Userspace API (UAPI) disintegration for which
the preparatory patches were pulled recently.  After these patches, userspace
headers will be segregated into:

        include/uapi/linux/.../foo.h

for the userspace interface stuff, and:

        include/linux/.../foo.h

for the strictly kernel internal stuff.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

10 files changed, 281 insertions, 230 deletions

diff --git a/fs/fat/Makefile b/fs/fat/Makefile
index e06190322c1c..964b634f6667 100644
--- a/fs/fat/Makefile
+++ b/fs/fat/Makefile
@@ -6,6 +6,6 @@ obj-$(CONFIG_FAT_FS) += fat.o
 obj-$(CONFIG_VFAT_FS) += vfat.o
 obj-$(CONFIG_MSDOS_FS) += msdos.o
 
-fat-y := cache.o dir.o fatent.o file.o inode.o misc.o
+fat-y := cache.o dir.o fatent.o file.o inode.o misc.o nfs.o
 vfat-y := namei_vfat.o
 msdos-y := namei_msdos.o
diff --git a/fs/fat/cache.c b/fs/fat/cache.c
index 1cc7038e273d..91ad9e1c9441 100644
--- a/fs/fat/cache.c
+++ b/fs/fat/cache.c
@@ -190,7 +190,8 @@ static void __fat_cache_inval_inode(struct inode *inode)
 	struct fat_cache *cache;
 
 	while (!list_empty(&i->cache_lru)) {
-		cache = list_entry(i->cache_lru.next, struct fat_cache, cache_list);
+		cache = list_entry(i->cache_lru.next,
+				   struct fat_cache, cache_list);
 		list_del_init(&cache->cache_list);
 		i->nr_caches--;
 		fat_cache_free(cache);
@@ -261,9 +262,10 @@ int fat_get_cluster(struct inode *inode, int cluster, int *fclus, int *dclus)
 		if (nr < 0)
 			goto out;
 		else if (nr == FAT_ENT_FREE) {
-			fat_fs_error_ratelimit(sb, "%s: invalid cluster chain"
-					       " (i_pos %lld)", __func__,
-					       MSDOS_I(inode)->i_pos);
+			fat_fs_error_ratelimit(sb,
+				       "%s: invalid cluster chain (i_pos %lld)",
+				       __func__,
+				       MSDOS_I(inode)->i_pos);
 			nr = -EIO;
 			goto out;
 		} else if (nr == FAT_ENT_EOF) {
diff --git a/fs/fat/dir.c b/fs/fat/dir.c
index dc49ed2cbffa..bca6d0a1255e 100644
--- a/fs/fat/dir.c
+++ b/fs/fat/dir.c
@@ -18,7 +18,7 @@
 #include <linux/time.h>
 #include <linux/buffer_head.h>
 #include <linux/compat.h>
-#include <asm/uaccess.h>
+#include <linux/uaccess.h>
 #include <linux/kernel.h>
 #include "fat.h"
 
@@ -123,7 +123,8 @@ static inline int fat_get_entry(struct inode *dir, loff_t *pos,
 {
 	/* Fast stuff first */
 	if (*bh && *de &&
-	    (*de - (struct msdos_dir_entry *)(*bh)->b_data) < MSDOS_SB(dir->i_sb)->dir_per_block - 1) {
+	   (*de - (struct msdos_dir_entry *)(*bh)->b_data) <
+				MSDOS_SB(dir->i_sb)->dir_per_block - 1) {
 		*pos += sizeof(struct msdos_dir_entry);
 		(*de)++;
 		return 0;
@@ -155,7 +156,8 @@ static int uni16_to_x8(struct super_block *sb, unsigned char *ascii,
 
 	while (*ip && ((len - NLS_MAX_CHARSET_SIZE) > 0)) {
 		ec = *ip++;
-		if ((charlen = nls->uni2char(ec, op, NLS_MAX_CHARSET_SIZE)) > 0) {
+		charlen = nls->uni2char(ec, op, NLS_MAX_CHARSET_SIZE);
+		if (charlen > 0) {
 			op += charlen;
 			len -= charlen;
 		} else {
@@ -172,12 +174,12 @@ static int uni16_to_x8(struct super_block *sb, unsigned char *ascii,
 	}
 
 	if (unlikely(*ip)) {
-		fat_msg(sb, KERN_WARNING, "filename was truncated while "
-			"converting.");
+		fat_msg(sb, KERN_WARNING,
+			"filename was truncated while converting.");
 	}
 
 	*op = 0;
-	return (op - ascii);
+	return op - ascii;
 }
 
 static inline int fat_uni_to_x8(struct super_block *sb, const wchar_t *uni,
@@ -205,7 +207,8 @@ fat_short2uni(struct nls_table *t, unsigned char *c, int clen, wchar_t *uni)
 }
 
 static inline int
-fat_short2lower_uni(struct nls_table *t, unsigned char *c, int clen, wchar_t *uni)
+fat_short2lower_uni(struct nls_table *t, unsigned char *c,
+		    int clen, wchar_t *uni)
 {
 	int charlen;
 	wchar_t wc;
@@ -220,7 +223,8 @@ fat_short2lower_uni(struct nls_table *t, unsigned char *c, int clen, wchar_t *un
 		if (!nc)
 			nc = *c;
 
-		if ( (charlen = t->char2uni(&nc, 1, uni)) < 0) {
+		charlen = t->char2uni(&nc, 1, uni);
+		if (charlen < 0) {
 			*uni = 0x003f;	/* a question mark */
 			charlen = 1;
 		}
@@ -537,7 +541,6 @@ end_of_dir:
 
 	return err;
 }
-
 EXPORT_SYMBOL_GPL(fat_search_long);
 
 struct fat_ioctl_filldir_callback {
@@ -574,7 +577,8 @@ static int __fat_readdir(struct inode *inode, struct file *filp, void *dirent,
 	/* Fake . and .. for the root directory. */
 	if (inode->i_ino == MSDOS_ROOT_INO) {
 		while (cpos < 2) {
-			if (filldir(dirent, "..", cpos+1, cpos, MSDOS_ROOT_INO, DT_DIR) < 0)
+			if (filldir(dirent, "..", cpos+1, cpos,
+				    MSDOS_ROOT_INO, DT_DIR) < 0)
 				goto out;
 			cpos++;
 			filp->f_pos++;
@@ -872,25 +876,26 @@ static int fat_get_short_entry(struct inode *dir, loff_t *pos,
 }
 
 /*
- * The ".." entry can not provide the "struct fat_slot_info" informations
- * for inode. So, this function provide the some informations only.
+ * The ".." entry can not provide the "struct fat_slot_info" information
+ * for inode, nor a usable i_pos. So, this function provides some information
+ * only.
+ *
+ * Since this function walks through the on-disk inodes within a directory,
+ * callers are responsible for taking any locks necessary to prevent the
+ * directory from changing.
  */
 int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh,
-			 struct msdos_dir_entry **de, loff_t *i_pos)
+			 struct msdos_dir_entry **de)
 {
-	loff_t offset;
+	loff_t offset = 0;
 
-	offset = 0;
-	*bh = NULL;
+	*de = NULL;
 	while (fat_get_short_entry(dir, &offset, bh, de) >= 0) {
-		if (!strncmp((*de)->name, MSDOS_DOTDOT, MSDOS_NAME)) {
-			*i_pos = fat_make_i_pos(dir->i_sb, *bh, *de);
+		if (!strncmp((*de)->name, MSDOS_DOTDOT, MSDOS_NAME))
 			return 0;
-		}
 	}
 	return -ENOENT;
 }
-
 EXPORT_SYMBOL_GPL(fat_get_dotdot_entry);
 
 /* See if directory is empty */
@@ -913,7 +918,6 @@ int fat_dir_empty(struct inode *dir)
 	brelse(bh);
 	return result;
 }
-
 EXPORT_SYMBOL_GPL(fat_dir_empty);
 
 /*
@@ -959,7 +963,6 @@ int fat_scan(struct inode *dir, const unsigned char *name,
 	}
 	return -ENOENT;
 }
-
 EXPORT_SYMBOL_GPL(fat_scan);
 
 static int __fat_remove_entries(struct inode *dir, loff_t pos, int nr_slots)
@@ -1047,7 +1050,6 @@ int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo)
 
 	return 0;
 }
-
 EXPORT_SYMBOL_GPL(fat_remove_entries);
 
 static int fat_zeroed_cluster(struct inode *dir, sector_t blknr, int nr_used,
@@ -1141,10 +1143,8 @@ int fat_alloc_new_dir(struct inode *dir, struct timespec *ts)
 		de[0].ctime_cs = de[1].ctime_cs = 0;
 		de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = 0;
 	}
-	de[0].start = cpu_to_le16(cluster);
-	de[0].starthi = cpu_to_le16(cluster >> 16);
-	de[1].start = cpu_to_le16(MSDOS_I(dir)->i_logstart);
-	de[1].starthi = cpu_to_le16(MSDOS_I(dir)->i_logstart >> 16);
+	fat_set_start(&de[0], cluster);
+	fat_set_start(&de[1], MSDOS_I(dir)->i_logstart);
 	de[0].size = de[1].size = 0;
 	memset(de + 2, 0, sb->s_blocksize - 2 * sizeof(*de));
 	set_buffer_uptodate(bhs[0]);
@@ -1161,7 +1161,6 @@ error_free:
 error:
 	return err;
 }
-
 EXPORT_SYMBOL_GPL(fat_alloc_new_dir);
 
 static int fat_add_new_entries(struct inode *dir, void *slots, int nr_slots,
@@ -1377,5 +1376,4 @@ error_remove:
 		__fat_remove_entries(dir, pos, free_slots);
 	return err;
 }
-
 EXPORT_SYMBOL_GPL(fat_add_entries);
diff --git a/fs/fat/fat.h b/fs/fat/fat.h
index 2deeeb86f331..ca7e8f8bad7c 100644
--- a/fs/fat/fat.h
+++ b/fs/fat/fat.h
@@ -5,6 +5,7 @@
 #include <linux/string.h>
 #include <linux/nls.h>
 #include <linux/fs.h>
+#include <linux/hash.h>
 #include <linux/mutex.h>
 #include <linux/ratelimit.h>
 #include <linux/msdos_fs.h>
@@ -23,30 +24,31 @@
 #define FAT_ERRORS_RO		3      /* remount r/o on error */
 
 struct fat_mount_options {
-	uid_t fs_uid;
-	gid_t fs_gid;
+	kuid_t fs_uid;
+	kgid_t fs_gid;
 	unsigned short fs_fmask;
 	unsigned short fs_dmask;
-	unsigned short codepage;  /* Codepage for shortname conversions */
-	char *iocharset;          /* Charset used for filename input/display */
-	unsigned short shortname; /* flags for shortname display/create rule */
-	unsigned char name_check; /* r = relaxed, n = normal, s = strict */
-	unsigned char errors;	  /* On error: continue, panic, remount-ro */
+	unsigned short codepage;   /* Codepage for shortname conversions */
+	char *iocharset;           /* Charset used for filename input/display */
+	unsigned short shortname;  /* flags for shortname display/create rule */
+	unsigned char name_check;  /* r = relaxed, n = normal, s = strict */
+	unsigned char errors;	   /* On error: continue, panic, remount-ro */
 	unsigned short allow_utime;/* permission for setting the [am]time */
-	unsigned quiet:1,         /* set = fake successful chmods and chowns */
-		 showexec:1,      /* set = only set x bit for com/exe/bat */
-		 sys_immutable:1, /* set = system files are immutable */
-		 dotsOK:1,        /* set = hidden and system files are named '.filename' */
-		 isvfat:1,        /* 0=no vfat long filename support, 1=vfat support */
-		 utf8:1,	  /* Use of UTF-8 character set (Default) */
-		 unicode_xlate:1, /* create escape sequences for unhandled Unicode */
-		 numtail:1,       /* Does first alias have a numeric '~1' type tail? */
-		 flush:1,	  /* write things quickly */
-		 nocase:1,	  /* Does this need case conversion? 0=need case conversion*/
-		 usefree:1,	  /* Use free_clusters for FAT32 */
-		 tz_utc:1,	  /* Filesystem timestamps are in UTC */
-		 rodir:1,	  /* allow ATTR_RO for directory */
-		 discard:1;	  /* Issue discard requests on deletions */
+	unsigned quiet:1,          /* set = fake successful chmods and chowns */
+		 showexec:1,       /* set = only set x bit for com/exe/bat */
+		 sys_immutable:1,  /* set = system files are immutable */
+		 dotsOK:1,         /* set = hidden and system files are named '.filename' */
+		 isvfat:1,         /* 0=no vfat long filename support, 1=vfat support */
+		 utf8:1,	   /* Use of UTF-8 character set (Default) */
+		 unicode_xlate:1,  /* create escape sequences for unhandled Unicode */
+		 numtail:1,        /* Does first alias have a numeric '~1' type tail? */
+		 flush:1,	   /* write things quickly */
+		 nocase:1,	   /* Does this need case conversion? 0=need case conversion*/
+		 usefree:1,	   /* Use free_clusters for FAT32 */
+		 tz_utc:1,	   /* Filesystem timestamps are in UTC */
+		 rodir:1,	   /* allow ATTR_RO for directory */
+		 discard:1,	   /* Issue discard requests on deletions */
+		 nfs:1;		   /* Do extra work needed for NFS export */
 };
 
 #define FAT_HASH_BITS	8
@@ -56,28 +58,28 @@ struct fat_mount_options {
  * MS-DOS file system in-core superblock data
  */
 struct msdos_sb_info {
-	unsigned short sec_per_clus; /* sectors/cluster */
-	unsigned short cluster_bits; /* log2(cluster_size) */
-	unsigned int cluster_size;   /* cluster size */
-	unsigned char fats,fat_bits; /* number of FATs, FAT bits (12 or 16) */
+	unsigned short sec_per_clus;  /* sectors/cluster */
+	unsigned short cluster_bits;  /* log2(cluster_size) */
+	unsigned int cluster_size;    /* cluster size */
+	unsigned char fats, fat_bits; /* number of FATs, FAT bits (12 or 16) */
 	unsigned short fat_start;
-	unsigned long fat_length;    /* FAT start & length (sec.) */
+	unsigned long fat_length;     /* FAT start & length (sec.) */
 	unsigned long dir_start;
-	unsigned short dir_entries;  /* root dir start & entries */
-	unsigned long data_start;    /* first data sector */
-	unsigned long max_cluster;   /* maximum cluster number */
-	unsigned long root_cluster;  /* first cluster of the root directory */
-	unsigned long fsinfo_sector; /* sector number of FAT32 fsinfo */
+	unsigned short dir_entries;   /* root dir start & entries */
+	unsigned long data_start;     /* first data sector */
+	unsigned long max_cluster;    /* maximum cluster number */
+	unsigned long root_cluster;   /* first cluster of the root directory */
+	unsigned long fsinfo_sector;  /* sector number of FAT32 fsinfo */
 	struct mutex fat_lock;
-	unsigned int prev_free;      /* previously allocated cluster number */
-	unsigned int free_clusters;  /* -1 if undefined */
+	unsigned int prev_free;       /* previously allocated cluster number */
+	unsigned int free_clusters;   /* -1 if undefined */
 	unsigned int free_clus_valid; /* is free_clusters valid? */
 	struct fat_mount_options options;
-	struct nls_table *nls_disk;  /* Codepage used on disk */
-	struct nls_table *nls_io;    /* Charset used for input and display */
-	const void *dir_ops;		     /* Opaque; default directory operations */
-	int dir_per_block;	     /* dir entries per block */
-	int dir_per_block_bits;	     /* log2(dir_per_block) */
+	struct nls_table *nls_disk;   /* Codepage used on disk */
+	struct nls_table *nls_io;     /* Charset used for input and display */
+	const void *dir_ops;	      /* Opaque; default directory operations */
+	int dir_per_block;	      /* dir entries per block */
+	int dir_per_block_bits;	      /* log2(dir_per_block) */
 
 	int fatent_shift;
 	struct fatent_operations *fatent_ops;
@@ -88,6 +90,9 @@ struct msdos_sb_info {
 
 	spinlock_t inode_hash_lock;
 	struct hlist_head inode_hashtable[FAT_HASH_SIZE];
+
+	spinlock_t dir_hash_lock;
+	struct hlist_head dir_hashtable[FAT_HASH_SIZE];
 };
 
 #define FAT_CACHE_VALID	0	/* special case for valid cache */
@@ -110,6 +115,7 @@ struct msdos_inode_info {
 	int i_attrs;		/* unused attribute bits */
 	loff_t i_pos;		/* on-disk position of directory entry or 0 */
 	struct hlist_node i_fat_hash;	/* hash by i_location */
+	struct hlist_node i_dir_hash;	/* hash by i_logstart */
 	struct rw_semaphore truncate_lock; /* protect bmap against truncate */
 	struct inode vfs_inode;
 };
@@ -262,7 +268,7 @@ 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_get_dotdot_entry(struct inode *dir, struct buffer_head **bh,
-				struct msdos_dir_entry **de, loff_t *i_pos);
+				struct msdos_dir_entry **de);
 extern int fat_alloc_new_dir(struct inode *dir, struct timespec *ts);
 extern int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
 			   struct fat_slot_info *sinfo);
@@ -322,7 +328,7 @@ extern long fat_generic_ioctl(struct file *filp, unsigned int cmd,
 			      unsigned long arg);
 extern const struct file_operations fat_file_operations;
 extern const struct inode_operations fat_file_inode_operations;
-extern int fat_setattr(struct dentry * dentry, struct iattr * attr);
+extern int fat_setattr(struct dentry *dentry, struct iattr *attr);
 extern void fat_truncate_blocks(struct inode *inode, loff_t offset);
 extern int fat_getattr(struct vfsmount *mnt, struct dentry *dentry,
 		       struct kstat *stat);
@@ -340,7 +346,12 @@ extern int fat_fill_super(struct super_block *sb, void *data, int silent,
 			  int isvfat, void (*setup)(struct super_block *));
 
 extern int fat_flush_inodes(struct super_block *sb, struct inode *i1,
-		            struct inode *i2);
+			    struct inode *i2);
+static inline unsigned long fat_dir_hash(int logstart)
+{
+	return hash_32(logstart, FAT_HASH_BITS);
+}
+
 /* fat/misc.c */
 extern __printf(3, 4) __cold
 void __fat_fs_error(struct super_block *sb, int report, const char *fmt, ...);
@@ -366,6 +377,14 @@ extern int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs);
 int fat_cache_init(void);
 void fat_cache_destroy(void);
 
+/* fat/nfs.c */
+struct fid;
+extern struct dentry *fat_fh_to_dentry(struct super_block *sb, struct fid *fid,
+				       int fh_len, int fh_type);
+extern struct dentry *fat_fh_to_parent(struct super_block *sb, struct fid *fid,
+				       int fh_len, int fh_type);
+extern struct dentry *fat_get_parent(struct dentry *child_dir);
+
 /* helper for printk */
 typedef unsigned long long	llu;
 
diff --git a/fs/fat/fatent.c b/fs/fat/fatent.c
index 31f08ab62c56..260705c58062 100644
--- a/fs/fat/fatent.c
+++ b/fs/fat/fatent.c
@@ -186,9 +186,6 @@ static void fat16_ent_put(struct fat_entry *fatent, int new)
 
 static void fat32_ent_put(struct fat_entry *fatent, int new)
 {
-	if (new == FAT_ENT_EOF)
-		new = EOF_FAT32;
-
 	WARN_ON(new & 0xf0000000);
 	new |= le32_to_cpu(*fatent->u.ent32_p) & ~0x0fffffff;
 	*fatent->u.ent32_p = cpu_to_le32(new);
@@ -203,15 +200,18 @@ static int fat12_ent_next(struct fat_entry *fatent)
 
 	fatent->entry++;
 	if (fatent->nr_bhs == 1) {
-		WARN_ON(ent12_p[0] > (u8 *)(bhs[0]->b_data + (bhs[0]->b_size - 2)));
-		WARN_ON(ent12_p[1] > (u8 *)(bhs[0]->b_data + (bhs[0]->b_size - 1)));
+		WARN_ON(ent12_p[0] > (u8 *)(bhs[0]->b_data +
+							(bhs[0]->b_size - 2)));
+		WARN_ON(ent12_p[1] > (u8 *)(bhs[0]->b_data +
+							(bhs[0]->b_size - 1)));
 		if (nextp < (u8 *)(bhs[0]->b_data + (bhs[0]->b_size - 1))) {
 			ent12_p[0] = nextp - 1;
 			ent12_p[1] = nextp;
 			return 1;
 		}
 	} else {
-		WARN_ON(ent12_p[0] != (u8 *)(bhs[0]->b_data + (bhs[0]->b_size - 1)));
+		WARN_ON(ent12_p[0] != (u8 *)(bhs[0]->b_data +
+							(bhs[0]->b_size - 1)));
 		WARN_ON(ent12_p[1] != (u8 *)bhs[1]->b_data);
 		ent12_p[0] = nextp - 1;
 		ent12_p[1] = nextp;
@@ -631,7 +631,6 @@ error:
 
 	return err;
 }
-
 EXPORT_SYMBOL_GPL(fat_free_clusters);
 
 /* 128kb is the whole sectors for FAT12 and FAT16 */
diff --git a/fs/fat/file.c b/fs/fat/file.c
index e007b8bd8e5e..a62e0ecbe2db 100644
--- a/fs/fat/file.c
+++ b/fs/fat/file.c
@@ -352,7 +352,7 @@ static int fat_allow_set_time(struct msdos_sb_info *sbi, struct inode *inode)
 {
 	umode_t allow_utime = sbi->options.allow_utime;
 
-	if (current_fsuid() != inode->i_uid) {
+	if (!uid_eq(current_fsuid(), inode->i_uid)) {
 		if (in_group_p(inode->i_gid))
 			allow_utime >>= 3;
 		if (allow_utime & MAY_WRITE)
@@ -407,9 +407,9 @@ int fat_setattr(struct dentry *dentry, struct iattr *attr)
 	}
 
 	if (((attr->ia_valid & ATTR_UID) &&
-	     (attr->ia_uid != sbi->options.fs_uid)) ||
+	     (!uid_eq(attr->ia_uid, sbi->options.fs_uid))) ||
 	    ((attr->ia_valid & ATTR_GID) &&
-	     (attr->ia_gid != sbi->options.fs_gid)) ||
+	     (!gid_eq(attr->ia_gid, sbi->options.fs_gid))) ||
 	    ((attr->ia_valid & ATTR_MODE) &&
 	     (attr->ia_mode & ~FAT_VALID_MODE)))
 		error = -EPERM;
diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index 05e897fe9866..76f60c642c06 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -281,15 +281,42 @@ static inline unsigned long fat_hash(loff_t i_pos)
 	return hash_32(i_pos, FAT_HASH_BITS);
 }
 
+static void dir_hash_init(struct super_block *sb)
+{
+	struct msdos_sb_info *sbi = MSDOS_SB(sb);
+	int i;
+
+	spin_lock_init(&sbi->dir_hash_lock);
+	for (i = 0; i < FAT_HASH_SIZE; i++)
+		INIT_HLIST_HEAD(&sbi->dir_hashtable[i]);
+}
+
 void fat_attach(struct inode *inode, loff_t i_pos)
 {
 	struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
-	struct hlist_head *head = sbi->inode_hashtable + fat_hash(i_pos);
 
-	spin_lock(&sbi->inode_hash_lock);
-	MSDOS_I(inode)->i_pos = i_pos;
-	hlist_add_head(&MSDOS_I(inode)->i_fat_hash, head);
-	spin_unlock(&sbi->inode_hash_lock);
+	if (inode->i_ino != MSDOS_ROOT_INO) {
+		struct hlist_head *head =   sbi->inode_hashtable
+					  + fat_hash(i_pos);
+
+		spin_lock(&sbi->inode_hash_lock);
+		MSDOS_I(inode)->i_pos = i_pos;
+		hlist_add_head(&MSDOS_I(inode)->i_fat_hash, head);
+		spin_unlock(&sbi->inode_hash_lock);
+	}
+
+	/* If NFS support is enabled, cache the mapping of start cluster
+	 * to directory inode. This is used during reconnection of
+	 * dentries to the filesystem root.
+	 */
+	if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
+		struct hlist_head *d_head = sbi->dir_hashtable;
+		d_head += fat_dir_hash(MSDOS_I(inode)->i_logstart);
+
+		spin_lock(&sbi->dir_hash_lock);
+		hlist_add_head(&MSDOS_I(inode)->i_dir_hash, d_head);
+		spin_unlock(&sbi->dir_hash_lock);
+	}
 }
 EXPORT_SYMBOL_GPL(fat_attach);
 
@@ -300,6 +327,12 @@ void fat_detach(struct inode *inode)
 	MSDOS_I(inode)->i_pos = 0;
 	hlist_del_init(&MSDOS_I(inode)->i_fat_hash);
 	spin_unlock(&sbi->inode_hash_lock);
+
+	if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
+		spin_lock(&sbi->dir_hash_lock);
+		hlist_del_init(&MSDOS_I(inode)->i_dir_hash);
+		spin_unlock(&sbi->dir_hash_lock);
+	}
 }
 EXPORT_SYMBOL_GPL(fat_detach);
 
@@ -504,6 +537,7 @@ static void init_once(void *foo)
 	ei->cache_valid_id = FAT_CACHE_VALID + 1;
 	INIT_LIST_HEAD(&ei->cache_lru);
 	INIT_HLIST_NODE(&ei->i_fat_hash);
+	INIT_HLIST_NODE(&ei->i_dir_hash);
 	inode_init_once(&ei->vfs_inode);
 }
 
@@ -521,6 +555,11 @@ static int __init fat_init_inodecache(void)
 
 static void __exit fat_destroy_inodecache(void)
 {
+	/*
+	 * Make sure all delayed rcu free inodes are flushed before we
+	 * destroy cache.
+	 */
+	rcu_barrier();
 	kmem_cache_destroy(fat_inode_cachep);
 }
 
@@ -663,125 +702,9 @@ static const struct super_operations fat_sops = {
 	.show_options	= fat_show_options,
 };
 
-/*
- * a FAT file handle with fhtype 3 is
- *  0/  i_ino - for fast, reliable lookup if still in the cache
- *  1/  i_generation - to see if i_ino is still valid
- *          bit 0 == 0 iff directory
- *  2/  i_pos(8-39) - if ino has changed, but still in cache
- *  3/  i_pos(4-7)|i_logstart - to semi-verify inode found at i_pos
- *  4/  i_pos(0-3)|parent->i_logstart - maybe used to hunt for the file on disc
- *
- * Hack for NFSv2: Maximum FAT entry number is 28bits and maximum
- * i_pos is 40bits (blocknr(32) + dir offset(8)), so two 4bits
- * of i_logstart is used to store the directory entry offset.
- */
-
-static struct dentry *fat_fh_to_dentry(struct super_block *sb,
-		struct fid *fid, int fh_len, int fh_type)
-{
-	struct inode *inode = NULL;
-	u32 *fh = fid->raw;
-
-	if (fh_len < 5 || fh_type != 3)
-		return NULL;
-
-	inode = ilookup(sb, fh[0]);
-	if (!inode || inode->i_generation != fh[1]) {
-		if (inode)
-			iput(inode);
-		inode = NULL;
-	}
-	if (!inode) {
-		loff_t i_pos;
-		int i_logstart = fh[3] & 0x0fffffff;
-
-		i_pos = (loff_t)fh[2] << 8;
-		i_pos |= ((fh[3] >> 24) & 0xf0) | (fh[4] >> 28);
-
-		/* try 2 - see if i_pos is in F-d-c
-		 * require i_logstart to be the same
-		 * Will fail if you truncate and then re-write
-		 */
-
-		inode = fat_iget(sb, i_pos);
-		if (inode && MSDOS_I(inode)->i_logstart != i_logstart) {
-			iput(inode);
-			inode = NULL;
-		}
-	}
-
-	/*
-	 * For now, do nothing if the inode is not found.
-	 *
-	 * What we could do is:
-	 *
-	 *	- follow the file starting at fh[4], and record the ".." entry,
-	 *	  and the name of the fh[2] entry.
-	 *	- then follow the ".." file finding the next step up.
-	 *
-	 * This way we build a path to the root of the tree. If this works, we
-	 * lookup the path and so get this inode into the cache.  Finally try
-	 * the fat_iget lookup again.  If that fails, then we are totally out
-	 * of luck.  But all that is for another day
-	 */
-	return d_obtain_alias(inode);
-}
-
-static int
-fat_encode_fh(struct inode *inode, __u32 *fh, int *lenp, struct inode *parent)
-{
-	int len = *lenp;
-	struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
-	loff_t i_pos;
-
-	if (len < 5) {
-		*lenp = 5;
-		return 255; /* no room */
-	}
-
-	i_pos = fat_i_pos_read(sbi, inode);
-	*lenp = 5;
-	fh[0] = inode->i_ino;
-	fh[1] = inode->i_generation;
-	fh[2] = i_pos >> 8;
-	fh[3] = ((i_pos & 0xf0) << 24) | MSDOS_I(inode)->i_logstart;
-	fh[4] = (i_pos & 0x0f) << 28;
-	if (parent)
-		fh[4] |= MSDOS_I(parent)->i_logstart;
-	return 3;
-}
-
-static struct dentry *fat_get_parent(struct dentry *child)
-{
-	struct super_block *sb = child->d_sb;
-	struct buffer_head *bh;
-	struct msdos_dir_entry *de;
-	loff_t i_pos;
-	struct dentry *parent;
-	struct inode *inode;
-	int err;
-
-	lock_super(sb);
-
-	err = fat_get_dotdot_entry(child->d_inode, &bh, &de, &i_pos);
-	if (err) {
-		parent = ERR_PTR(err);
-		goto out;
-	}
-	inode = fat_build_inode(sb, de, i_pos);
-	brelse(bh);
-
-	parent = d_obtain_alias(inode);
-out:
-	unlock_super(sb);
-
-	return parent;
-}
-
 static const struct export_operations fat_export_ops = {
-	.encode_fh	= fat_encode_fh,
 	.fh_to_dentry	= fat_fh_to_dentry,
+	.fh_to_parent	= fat_fh_to_parent,
 	.get_parent	= fat_get_parent,
 };
 
@@ -791,10 +714,12 @@ static int fat_show_options(struct seq_file *m, struct dentry *root)
 	struct fat_mount_options *opts = &sbi->options;
 	int isvfat = opts->isvfat;
 
-	if (opts->fs_uid != 0)
-		seq_printf(m, ",uid=%u", opts->fs_uid);
-	if (opts->fs_gid != 0)
-		seq_printf(m, ",gid=%u", opts->fs_gid);
+	if (!uid_eq(opts->fs_uid, GLOBAL_ROOT_UID))
+		seq_printf(m, ",uid=%u",
+				from_kuid_munged(&init_user_ns, opts->fs_uid));
+	if (!gid_eq(opts->fs_gid, GLOBAL_ROOT_GID))
+		seq_printf(m, ",gid=%u",
+				from_kgid_munged(&init_user_ns, opts->fs_gid));
 	seq_printf(m, ",fmask=%04o", opts->fs_fmask);
 	seq_printf(m, ",dmask=%04o", opts->fs_dmask);
 	if (opts->allow_utime)
@@ -829,6 +754,8 @@ static int fat_show_options(struct seq_file *m, struct dentry *root)
 		seq_puts(m, ",usefree");
 	if (opts->quiet)
 		seq_puts(m, ",quiet");
+	if (opts->nfs)
+		seq_puts(m, ",nfs");
 	if (opts->showexec)
 		seq_puts(m, ",showexec");
 	if (opts->sys_immutable)
@@ -873,7 +800,7 @@ enum {
 	Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes,
 	Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes,
 	Opt_obsolete, Opt_flush, Opt_tz_utc, Opt_rodir, Opt_err_cont,
-	Opt_err_panic, Opt_err_ro, Opt_discard, Opt_err,
+	Opt_err_panic, Opt_err_ro, Opt_discard, Opt_nfs, Opt_err,
 };
 
 static const match_table_t fat_tokens = {
@@ -902,6 +829,7 @@ static const match_table_t fat_tokens = {
 	{Opt_err_panic, "errors=panic"},
 	{Opt_err_ro, "errors=remount-ro"},
 	{Opt_discard, "discard"},
+	{Opt_nfs, "nfs"},
 	{Opt_obsolete, "conv=binary"},
 	{Opt_obsolete, "conv=text"},
 	{Opt_obsolete, "conv=auto"},
@@ -982,6 +910,7 @@ static int parse_options(struct super_block *sb, char *options, int is_vfat,
 	opts->numtail = 1;
 	opts->usefree = opts->nocase = 0;
 	opts->tz_utc = 0;
+	opts->nfs = 0;
 	opts->errors = FAT_ERRORS_RO;
 	*debug = 0;
 
@@ -1037,12 +966,16 @@ static int parse_options(struct super_block *sb, char *options, int is_vfat,
 		case Opt_uid:
 			if (match_int(&args[0], &option))
 				return 0;
-			opts->fs_uid = option;
+			opts->fs_uid = make_kuid(current_user_ns(), option);
+			if (!uid_valid(opts->fs_uid))
+				return 0;
 			break;
 		case Opt_gid:
 			if (match_int(&args[0], &option))
 				return 0;
-			opts->fs_gid = option;
+			opts->fs_gid = make_kgid(current_user_ns(), option);
+			if (!gid_valid(opts->fs_gid))
+				return 0;
 			break;
 		case Opt_umask:
 			if (match_octal(&args[0], &option))
@@ -1142,6 +1075,9 @@ static int parse_options(struct super_block *sb, char *options, int is_vfat,
 		case Opt_discard:
 			opts->discard = 1;
 			break;
+		case Opt_nfs:
+			opts->nfs = 1;
+			break;
 
 		/* obsolete mount options */
 		case Opt_obsolete:
@@ -1432,6 +1368,7 @@ int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
 
 	/* set up enough so that it can read an inode */
 	fat_hash_init(sb);
+	dir_hash_init(sb);
 	fat_ent_access_init(sb);
 
 	/*
@@ -1486,6 +1423,7 @@ int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
 	}
 	error = -ENOMEM;
 	insert_inode_hash(root_inode);
+	fat_attach(root_inode, 0);
 	sb->s_root = d_make_root(root_inode);
 	if (!sb->s_root) {
 		fat_msg(sb, KERN_ERR, "get root inode failed");
@@ -1525,18 +1463,14 @@ static int writeback_inode(struct inode *inode)
 {
 
 	int ret;
-	struct address_space *mapping = inode->i_mapping;
-	struct writeback_control wbc = {
-	       .sync_mode = WB_SYNC_NONE,
-	      .nr_to_write = 0,
-	};
-	/* if we used WB_SYNC_ALL, sync_inode waits for the io for the
-	* inode to finish.  So WB_SYNC_NONE is sent down to sync_inode
+
+	/* if we used wait=1, sync_inode_metadata waits for the io for the
+	* inode to finish.  So wait=0 is sent down to sync_inode_metadata
 	* and filemap_fdatawrite is used for the data blocks
 	*/
-	ret = sync_inode(inode, &wbc);
+	ret = sync_inode_metadata(inode, 0);
 	if (!ret)
-	       ret = filemap_fdatawrite(mapping);
+		ret = filemap_fdatawrite(inode->i_mapping);
 	return ret;
 }
 
diff --git a/fs/fat/namei_msdos.c b/fs/fat/namei_msdos.c
index b0e12bf9f4a1..c1055e778fff 100644
--- a/fs/fat/namei_msdos.c
+++ b/fs/fat/namei_msdos.c
@@ -407,7 +407,7 @@ out:
 static int msdos_unlink(struct inode *dir, struct dentry *dentry)
 {
 	struct inode *inode = dentry->d_inode;
-	struct super_block *sb= inode->i_sb;
+	struct super_block *sb = inode->i_sb;
 	struct fat_slot_info sinfo;
 	int err;
 
@@ -440,7 +440,7 @@ static int do_msdos_rename(struct inode *old_dir, unsigned char *old_name,
 	struct inode *old_inode, *new_inode;
 	struct fat_slot_info old_sinfo, sinfo;
 	struct timespec ts;
-	loff_t dotdot_i_pos, new_i_pos;
+	loff_t new_i_pos;
 	int err, old_attrs, is_dir, update_dotdot, corrupt = 0;
 
 	old_sinfo.bh = sinfo.bh = dotdot_bh = NULL;
@@ -456,8 +456,7 @@ static int do_msdos_rename(struct inode *old_dir, unsigned char *old_name,
 	is_dir = S_ISDIR(old_inode->i_mode);
 	update_dotdot = (is_dir && old_dir != new_dir);
 	if (update_dotdot) {
-		if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de,
-					 &dotdot_i_pos) < 0) {
+		if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de)) {
 			err = -EIO;
 			goto out;
 		}
diff --git a/fs/fat/namei_vfat.c b/fs/fat/namei_vfat.c
index 6a6d8c0715a1..e535dd75b986 100644
--- a/fs/fat/namei_vfat.c
+++ b/fs/fat/namei_vfat.c
@@ -914,7 +914,7 @@ static int vfat_rename(struct inode *old_dir, struct dentry *old_dentry,
 	struct inode *old_inode, *new_inode;
 	struct fat_slot_info old_sinfo, sinfo;
 	struct timespec ts;
-	loff_t dotdot_i_pos, new_i_pos;
+	loff_t new_i_pos;
 	int err, is_dir, update_dotdot, corrupt = 0;
 	struct super_block *sb = old_dir->i_sb;
 
@@ -929,8 +929,7 @@ static int vfat_rename(struct inode *old_dir, struct dentry *old_dentry,
 	is_dir = S_ISDIR(old_inode->i_mode);
 	update_dotdot = (is_dir && old_dir != new_dir);
 	if (update_dotdot) {
-		if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de,
-					 &dotdot_i_pos) < 0) {
+		if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de)) {
 			err = -EIO;
 			goto out;
 		}
diff --git a/fs/fat/nfs.c b/fs/fat/nfs.c
new file mode 100644
index 000000000000..ef4b5faba87b
--- /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);
+}