reiserfs: locking, handle nested locks properly

The reiserfs write lock replaced the BKL and uses similar semantics.

Frederic's locking code makes a distinction between when the lock is nested
and when it's being acquired/released, but I don't think that's the right
distinction to make.

The right distinction is between the lock being released at end-of-use and
the lock being released for a schedule. The unlock should return the depth
and the lock should restore it, rather than the other way around as it is now.

This patch implements that and adds a number of places where the lock
should be dropped.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>

1 files changed, 3 insertions, 4 deletions

diff --git a/fs/reiserfs/ioctl.c b/fs/reiserfs/ioctl.c
index 15cb5fe6b425..946ccbf5b5a1 100644
--- a/fs/reiserfs/ioctl.c
+++ b/fs/reiserfs/ioctl.c
@@ -167,7 +167,6 @@ int reiserfs_commit_write(struct file *f, struct page *page,
 int reiserfs_unpack(struct inode *inode, struct file *filp)
 {
         int retval = 0;
-        int depth;
         int index;
         struct page *page;
         struct address_space *mapping;
@@ -183,11 +182,11 @@ int reiserfs_unpack(struct inode *inode, struct file *filp)
                 return 0;
         }
 
-        depth = reiserfs_write_lock_once(inode->i_sb);
-
         /* we need to make sure nobody is changing the file size beneath us */
         reiserfs_mutex_lock_safe(&inode->i_mutex, inode->i_sb);
 
+        reiserfs_write_lock(inode->i_sb);
+
         write_from = inode->i_size & (blocksize - 1);
         /* if we are on a block boundary, we are already unpacked.  */
         if (write_from == 0) {
@@ -221,6 +220,6 @@ int reiserfs_unpack(struct inode *inode, struct file *filp)
 
       out:
         mutex_unlock(&inode->i_mutex);
-        reiserfs_write_unlock_once(inode->i_sb, depth);
+        reiserfs_write_unlock(inode->i_sb);
         return retval;
 }