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, 8 insertions, 2 deletions

diff --git a/fs/reiserfs/resize.c b/fs/reiserfs/resize.c
index 3ce02cff5e90..a4ef5cd606eb 100644
--- a/fs/reiserfs/resize.c
+++ b/fs/reiserfs/resize.c
@@ -34,6 +34,7 @@ int reiserfs_resize(struct super_block *s, unsigned long block_count_new)
 	unsigned long int block_count, free_blocks;
 	int i;
 	int copy_size;
+	int depth;
 
 	sb = SB_DISK_SUPER_BLOCK(s);
 
@@ -43,7 +44,9 @@ int reiserfs_resize(struct super_block *s, unsigned long block_count_new)
 	}
 
 	/* check the device size */
+	depth = reiserfs_write_unlock_nested(s);
 	bh = sb_bread(s, block_count_new - 1);
+	reiserfs_write_lock_nested(s, depth);
 	if (!bh) {
 		printk("reiserfs_resize: can\'t read last block\n");
 		return -EINVAL;
@@ -125,9 +128,12 @@ int reiserfs_resize(struct super_block *s, unsigned long block_count_new)
 		 * transaction begins, and the new bitmaps don't matter if the
 		 * transaction fails. */
 		for (i = bmap_nr; i < bmap_nr_new; i++) {
+			int depth;
 			/* don't use read_bitmap_block since it will cache
 			 * the uninitialized bitmap */
+			depth = reiserfs_write_unlock_nested(s);
 			bh = sb_bread(s, i * s->s_blocksize * 8);
+			reiserfs_write_lock_nested(s, depth);
 			if (!bh) {
 				vfree(bitmap);
 				return -EIO;
@@ -138,9 +144,9 @@ int reiserfs_resize(struct super_block *s, unsigned long block_count_new)
 
 			set_buffer_uptodate(bh);
 			mark_buffer_dirty(bh);
-			reiserfs_write_unlock(s);
+			depth = reiserfs_write_unlock_nested(s);
 			sync_dirty_buffer(bh);
-			reiserfs_write_lock(s);
+			reiserfs_write_lock_nested(s, depth);
 			// update bitmap_info stuff
 			bitmap[i].free_count = sb_blocksize(sb) * 8 - 1;
 			brelse(bh);