fat (exportfs): fix dentry reconnection

[karo-tx-linux.git] / fs / fat / inode.c

diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index 3cdf1d0a1846ca31fe30014aa204fff114bb643b..973296b9dd3be8f13fabec26e112d74e23145f6e 100644 (file)
--- 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);
 }
 
@@ -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,
 };
 
@@ -704,6 +752,8 @@ 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)
@@ -748,7 +798,7 @@ 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 = {
@@ -777,6 +827,7 @@ 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"},
@@ -857,6 +908,7 @@ 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;
 
@@ -1017,6 +1069,9 @@ 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:
@@ -1307,6 +1362,7 @@ 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);
 
        /*
@@ -1361,6 +1417,7 @@ 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");