On Fri, May 01, 2009 at 09:30:51AM -0400, Chris Mason wrote: > On Fri, 2009-05-01 at 15:19 +0200, Frederic Weisbecker wrote: > > On Fri, May 01, 2009 at 07:47:34AM +0200, Ingo Molnar wrote: > > > > > > * Frederic Weisbecker <fweisbec@xxxxxxxxx> wrote: > > > > > > > reiserfs_read_bitmap_block() uses sb_bread() to read the bitmap block. This > > > > helper might sleep. > > > > > > > > Then, when the bkl was used, it was released at this point. We can then > > > > relax the write lock too here. > > > > > > > > [ Impact: release the reiserfs write lock when it is not needed ] > > > > > > > > Cc: Jeff Mahoney <jeffm@xxxxxxxx> > > > > Cc: Chris Mason <chris.mason@xxxxxxxxxx> > > > > Cc: Alexander Beregalov <a.beregalov@xxxxxxxxx> > > > > Signed-off-by: Frederic Weisbecker <fweisbec@xxxxxxxxx> > > > > --- > > > > fs/reiserfs/bitmap.c | 2 ++ > > > > 1 files changed, 2 insertions(+), 0 deletions(-) > > > > > > > > diff --git a/fs/reiserfs/bitmap.c b/fs/reiserfs/bitmap.c > > > > index 1470334..6854957 100644 > > > > --- a/fs/reiserfs/bitmap.c > > > > +++ b/fs/reiserfs/bitmap.c > > > > @@ -1249,7 +1249,9 @@ struct buffer_head *reiserfs_read_bitmap_block(struct super_block *sb, > > > > else if (bitmap == 0) > > > > block = (REISERFS_DISK_OFFSET_IN_BYTES >> sb->s_blocksize_bits) + 1; > > > > > > > > + reiserfs_write_unlock(sb); > > > > bh = sb_bread(sb, block); > > > > + reiserfs_write_lock(sb); > > > > if (bh == NULL) > > > > reiserfs_warning(sb, "sh-2029: %s: bitmap block (#%u) " > > > > "reading failed", __func__, block); > > > > > > Note, there's a side-effect here: the access to sb->b_blocksize is > > > moved outside of the lock. Previously it was accessed via the BKL. > > > On a mounted filesystem sb->b_blocksize is not supposed to change, > > > so it's probably not an issue - but wanted to mention it. > > > Indeed. Well I guess it can't be dynamically changed. > > This is something that can be chosen with mkfs on filesystem creation > > but I guess it can't be changed, at least not while the filesystem > > is mounted. I hope... > > The blocksize should only be changing very early in the mount. It is > basically: > > set the block size to something > read the super block > read the block size from the super block > set the block size to the correct value > use it from then on. > > This should all be done with by the time we read bitmaps. > > -chris Ok, thanks. So I guess we can keep it as is without a local variable. -- To unsubscribe from this list: send the line "unsubscribe reiserfs-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
