xfs: Fix error return for fallocate() on XFS

[safe/jmp/linux-2.6] / fs / super.c

diff --git a/fs/super.c b/fs/super.c
index 1cb26a3..19eb70b 100644 (file)
--- a/fs/super.c
+++ b/fs/super.c
@@ -465,6 +465,48 @@ rescan:
 }
 
 EXPORT_SYMBOL(get_super);
+
+/**
+ * get_active_super - get an active reference to the superblock of a device
+ * @bdev: device to get the superblock for
+ *
+ * Scans the superblock list and finds the superblock of the file system
+ * mounted on the device given.  Returns the superblock with an active
+ * reference and s_umount held exclusively or %NULL if none was found.
+ */
+struct super_block *get_active_super(struct block_device *bdev)
+{
+       struct super_block *sb;
+
+       if (!bdev)
+               return NULL;
+
+       spin_lock(&sb_lock);
+       list_for_each_entry(sb, &super_blocks, s_list) {
+               if (sb->s_bdev != bdev)
+                       continue;
+
+               sb->s_count++;
+               spin_unlock(&sb_lock);
+               down_write(&sb->s_umount);
+               if (sb->s_root) {
+                       spin_lock(&sb_lock);
+                       if (sb->s_count > S_BIAS) {
+                               atomic_inc(&sb->s_active);
+                               sb->s_count--;
+                               spin_unlock(&sb_lock);
+                               return sb;
+                       }
+                       spin_unlock(&sb_lock);
+               }
+               up_write(&sb->s_umount);
+               put_super(sb);
+               yield();
+               spin_lock(&sb_lock);
+       }
+       spin_unlock(&sb_lock);
+       return NULL;
+}
  
 struct super_block * user_get_super(dev_t dev)
 {
@@ -527,11 +569,15 @@ int do_remount_sb(struct super_block *sb, int flags, void *data, int force)
 {
        int retval;
        int remount_rw;
-       
+
+       if (sb->s_frozen != SB_UNFROZEN)
+               return -EBUSY;
+
 #ifdef CONFIG_BLOCK
        if (!(flags & MS_RDONLY) && bdev_read_only(sb->s_bdev))
                return -EACCES;
 #endif
+
        if (flags & MS_RDONLY)
                acct_auto_close(sb);
        shrink_dcache_sb(sb);