1 files changed, 55 insertions, 132 deletions

diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index 4e5a6ac54ebd..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);
 }
 
@@ -668,125 +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,
 };
 
@@ -836,6 +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)
@@ -880,7 +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 = {
@@ -909,6 +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"},
@@ -989,6 +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;
 
@@ -1153,6 +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:
@@ -1443,6 +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);
 
         /*
@@ -1497,6 +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");
@@ -1536,18 +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;
 }