1 files changed, 115 insertions, 3 deletions

diff --git a/fs/jfs/super.c b/fs/jfs/super.c
index 4f6cfebc82db..143bcd1d5eaa 100644
--- a/fs/jfs/super.c
+++ b/fs/jfs/super.c
@@ -26,6 +26,7 @@
 #include <linux/moduleparam.h>
 #include <linux/kthread.h>
 #include <linux/posix_acl.h>
+#include <linux/buffer_head.h>
 #include <asm/uaccess.h>
 #include <linux/seq_file.h>
 
@@ -298,7 +299,7 @@ static int parse_options(char *options, struct super_block *sb, s64 *newLVSize,
                         break;
                 }
 
-#if defined(CONFIG_QUOTA)
+#ifdef CONFIG_QUOTA
                 case Opt_quota:
                 case Opt_usrquota:
                         *flag |= JFS_USRQUOTA;
@@ -597,7 +598,7 @@ static int jfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
         if (sbi->flag & JFS_NOINTEGRITY)
                 seq_puts(seq, ",nointegrity");
 
-#if defined(CONFIG_QUOTA)
+#ifdef CONFIG_QUOTA
         if (sbi->flag & JFS_USRQUOTA)
                 seq_puts(seq, ",usrquota");
 
@@ -608,6 +609,113 @@ static int jfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
         return 0;
 }
 
+#ifdef CONFIG_QUOTA
+
+/* Read data from quotafile - avoid pagecache and such because we cannot afford
+ * acquiring the locks... As quota files are never truncated and quota code
+ * itself serializes the operations (and noone else should touch the files)
+ * we don't have to be afraid of races */
+static ssize_t jfs_quota_read(struct super_block *sb, int type, char *data,
+                              size_t len, loff_t off)
+{
+        struct inode *inode = sb_dqopt(sb)->files[type];
+        sector_t blk = off >> sb->s_blocksize_bits;
+        int err = 0;
+        int offset = off & (sb->s_blocksize - 1);
+        int tocopy;
+        size_t toread;
+        struct buffer_head tmp_bh;
+        struct buffer_head *bh;
+        loff_t i_size = i_size_read(inode);
+
+        if (off > i_size)
+                return 0;
+        if (off+len > i_size)
+                len = i_size-off;
+        toread = len;
+        while (toread > 0) {
+                tocopy = sb->s_blocksize - offset < toread ?
+                                sb->s_blocksize - offset : toread;
+
+                tmp_bh.b_state = 0;
+                tmp_bh.b_size = 1 << inode->i_blkbits;
+                err = jfs_get_block(inode, blk, &tmp_bh, 0);
+                if (err)
+                        return err;
+                if (!buffer_mapped(&tmp_bh))    /* A hole? */
+                        memset(data, 0, tocopy);
+                else {
+                        bh = sb_bread(sb, tmp_bh.b_blocknr);
+                        if (!bh)
+                                return -EIO;
+                        memcpy(data, bh->b_data+offset, tocopy);
+                        brelse(bh);
+                }
+                offset = 0;
+                toread -= tocopy;
+                data += tocopy;
+                blk++;
+        }
+        return len;
+}
+
+/* Write to quotafile */
+static ssize_t jfs_quota_write(struct super_block *sb, int type,
+                               const char *data, size_t len, loff_t off)
+{
+        struct inode *inode = sb_dqopt(sb)->files[type];
+        sector_t blk = off >> sb->s_blocksize_bits;
+        int err = 0;
+        int offset = off & (sb->s_blocksize - 1);
+        int tocopy;
+        size_t towrite = len;
+        struct buffer_head tmp_bh;
+        struct buffer_head *bh;
+
+        mutex_lock(&inode->i_mutex);
+        while (towrite > 0) {
+                tocopy = sb->s_blocksize - offset < towrite ?
+                                sb->s_blocksize - offset : towrite;
+
+                tmp_bh.b_state = 0;
+                tmp_bh.b_size = 1 << inode->i_blkbits;
+                err = jfs_get_block(inode, blk, &tmp_bh, 1);
+                if (err)
+                        goto out;
+                if (offset || tocopy != sb->s_blocksize)
+                        bh = sb_bread(sb, tmp_bh.b_blocknr);
+                else
+                        bh = sb_getblk(sb, tmp_bh.b_blocknr);
+                if (!bh) {
+                        err = -EIO;
+                        goto out;
+                }
+                lock_buffer(bh);
+                memcpy(bh->b_data+offset, data, tocopy);
+                flush_dcache_page(bh->b_page);
+                set_buffer_uptodate(bh);
+                mark_buffer_dirty(bh);
+                unlock_buffer(bh);
+                brelse(bh);
+                offset = 0;
+                towrite -= tocopy;
+                data += tocopy;
+                blk++;
+        }
+out:
+        if (len == towrite)
+                return err;
+        if (inode->i_size < off+len-towrite)
+                i_size_write(inode, off+len-towrite);
+        inode->i_version++;
+        inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+        mark_inode_dirty(inode);
+        mutex_unlock(&inode->i_mutex);
+        return len - towrite;
+}
+
+#endif
+
 static struct super_operations jfs_super_operations = {
         .alloc_inode    = jfs_alloc_inode,
         .destroy_inode  = jfs_destroy_inode,
@@ -621,7 +729,11 @@ static struct super_operations jfs_super_operations = {
         .unlockfs       = jfs_unlockfs,
         .statfs         = jfs_statfs,
         .remount_fs     = jfs_remount,
-        .show_options   = jfs_show_options
+        .show_options   = jfs_show_options,
+#ifdef CONFIG_QUOTA
+        .quota_read     = jfs_quota_read,
+        .quota_write    = jfs_quota_write,
+#endif
 };
 
 static struct export_operations jfs_export_operations = {