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>
diff --git a/fs/reiserfs/resize.c b/fs/reiserfs/resize.c
index 3ce02cf..a4ef5cd 100644
--- a/fs/reiserfs/resize.c
+++ b/fs/reiserfs/resize.c
@@ -34,6 +34,7 @@
unsigned long int block_count, free_blocks;
int i;
int copy_size;
+ int depth;
sb = SB_DISK_SUPER_BLOCK(s);
@@ -43,7 +44,9 @@
}
/* 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 @@
* 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 @@
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);