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Commit 7669e8fb authored by Steven J. Magnani's avatar Steven J. Magnani Committed by Linus Torvalds
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fat (exportfs): fix dentry reconnection 



Maintain an index of directory inodes by starting cluster, so that
fat_get_parent() can return the proper cached inode rather than inventing
one that cannot be traced back to the filesystem root.

Add a new msdos/vfat binary mount option "nfs" so that FAT filesystems
that are _not_ exported via NFS are not saddled with maintenance of an
index they will never use.

Finally, simplify NFS file handle generation and lookups.  An
ext2-congruent implementation is adequate for FAT needs.

Signed-off-by: default avatarSteven J. Magnani <steve@digidescorp.com>
Acked-by: default avatarOGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 21b6633d

fs/fat/dir.c

+11 −9
Original line number Diff line number Diff line
@@ -872,22 +872,24 @@ 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;

}

fs/fat/fat.h

+12 −15
Original line number Diff line number Diff line
@@ -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>
@@ -46,7 +47,8 @@ struct fat_mount_options { 
		 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 */

		 discard:1,	  /* Issue discard requests on deletions */

		 nfs:1;		  /* Do extra work needed for NFS export */

};



#define FAT_HASH_BITS	8
@@ -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);
@@ -341,18 +347,9 @@ extern int fat_fill_super(struct super_block *sb, void *data, int silent, 


extern int fat_flush_inodes(struct super_block *sb, struct inode *i1,

		            struct inode *i2);

static inline loff_t fat_i_pos_read(struct msdos_sb_info *sbi,

				    struct inode *inode)

static inline unsigned long fat_dir_hash(int logstart)

{

	loff_t i_pos;

#if BITS_PER_LONG == 32

	spin_lock(&sbi->inode_hash_lock);

#endif

	i_pos = MSDOS_I(inode)->i_pos;

#if BITS_PER_LONG == 32

	spin_unlock(&sbi->inode_hash_lock);

#endif

	return i_pos;

	return hash_32(logstart, FAT_HASH_BITS);

}



/* fat/misc.c */
@@ -382,10 +379,10 @@ void fat_cache_destroy(void); 


/* fat/nfs.c */

struct fid;

extern int fat_encode_fh(struct inode *inode, __u32 *fh, int *lenp,

			 struct inode *parent);

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 */

fs/fat/inode.c

+64 −7
Original line number Diff line number Diff line
@@ -281,16 +281,43 @@ 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);



	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);



void fat_detach(struct inode *inode)
@@ -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);

}
@@ -562,6 +596,20 @@ static int fat_statfs(struct dentry *dentry, struct kstatfs *buf) 
	return 0;

}



static inline loff_t fat_i_pos_read(struct msdos_sb_info *sbi,

				    struct inode *inode)

{

	loff_t i_pos;

#if BITS_PER_LONG == 32

	spin_lock(&sbi->inode_hash_lock);

#endif

	i_pos = MSDOS_I(inode)->i_pos;

#if BITS_PER_LONG == 32

	spin_unlock(&sbi->inode_hash_lock);

#endif

	return i_pos;

}



static int __fat_write_inode(struct inode *inode, int wait)

{

	struct super_block *sb = inode->i_sb;
@@ -655,8 +703,8 @@ static const struct super_operations fat_sops = { 
};



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,

};
@@ -706,6 +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)
@@ -750,7 +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 = {
@@ -779,6 +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"},
@@ -859,6 +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;
@@ -1023,6 +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:
@@ -1313,6 +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);



	/*
@@ -1367,6 +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");

fs/fat/namei_msdos.c

+2 −3
Original line number Diff line number Diff line
@@ -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;

		}

fs/fat/namei_vfat.c

+2 −3
Original line number Diff line number Diff line
@@ -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;

		}