vfs: mnt_want_write_file(): fix special file handling

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

diff --git a/fs/super.c b/fs/super.c
index 83b4741..2761d3e 100644 (file)
--- a/fs/super.c
+++ b/fs/super.c
@@ -545,24 +545,18 @@ int do_remount_sb(struct super_block *sb, int flags, void *data, int force)
        if ((flags & MS_RDONLY) && !(sb->s_flags & MS_RDONLY)) {
                if (force)
                        mark_files_ro(sb);
-               else if (!fs_may_remount_ro(sb)) {
-                       unlock_kernel();
+               else if (!fs_may_remount_ro(sb))
                        return -EBUSY;
-               }
                retval = vfs_dq_off(sb, 1);
-               if (retval < 0 && retval != -ENOSYS) {
-                       unlock_kernel();
+               if (retval < 0 && retval != -ENOSYS)
                        return -EBUSY;
-               }
        }
        remount_rw = !(flags & MS_RDONLY) && (sb->s_flags & MS_RDONLY);
 
        if (sb->s_op->remount_fs) {
                retval = sb->s_op->remount_fs(sb, &flags, data);
-               if (retval) {
-                       unlock_kernel();
+               if (retval)
                        return retval;
-               }
        }
        sb->s_flags = (sb->s_flags & ~MS_RMT_MASK) | (flags & MS_RMT_MASK);
        if (remount_rw)
@@ -614,6 +608,7 @@ void emergency_remount(void)
 
 static DEFINE_IDA(unnamed_dev_ida);
 static DEFINE_SPINLOCK(unnamed_dev_lock);/* protects the above */
+static int unnamed_dev_start = 0; /* don't bother trying below it */
 
 int set_anon_super(struct super_block *s, void *data)
 {
@@ -624,7 +619,9 @@ int set_anon_super(struct super_block *s, void *data)
        if (ida_pre_get(&unnamed_dev_ida, GFP_ATOMIC) == 0)
                return -ENOMEM;
        spin_lock(&unnamed_dev_lock);
-       error = ida_get_new(&unnamed_dev_ida, &dev);
+       error = ida_get_new_above(&unnamed_dev_ida, unnamed_dev_start, &dev);
+       if (!error)
+               unnamed_dev_start = dev + 1;
        spin_unlock(&unnamed_dev_lock);
        if (error == -EAGAIN)
                /* We raced and lost with another CPU. */
@@ -635,6 +632,8 @@ int set_anon_super(struct super_block *s, void *data)
        if ((dev & MAX_ID_MASK) == (1 << MINORBITS)) {
                spin_lock(&unnamed_dev_lock);
                ida_remove(&unnamed_dev_ida, dev);
+               if (unnamed_dev_start > dev)
+                       unnamed_dev_start = dev;
                spin_unlock(&unnamed_dev_lock);
                return -EMFILE;
        }
@@ -651,6 +650,8 @@ void kill_anon_super(struct super_block *sb)
        generic_shutdown_super(sb);
        spin_lock(&unnamed_dev_lock);
        ida_remove(&unnamed_dev_ida, slot);
+       if (slot < unnamed_dev_start)
+               unnamed_dev_start = slot;
        spin_unlock(&unnamed_dev_lock);
 }