On Fri, Jun 29, 2018 at 04:42:41PM +0300, Nikolay Borisov wrote: > > > On 29.06.2018 16:07, Qu Wenruo wrote: > > > > > > On 2018年06月29日 20:46, David Sterba wrote: > >> On Wed, Jun 27, 2018 at 04:38:24PM +0300, Nikolay Borisov wrote: > >>> EXTENT_BUFFER_DUMMY is an awful name for this flag. Buffers which have > >>> this flag set are not in any way dummy. Rather, they are private in > >>> the sense that are not linked to the global buffer tree. This flag has > >>> subtle implications to the way free_extent_buffer work for example, as > >>> well as controls whether page->mapping->private_lock is held during > >>> extent_buffer release. Pages for a private buffer cannot be under io, > >>> nor can they be written by a 3rd party so taking the lock is > >>> unnecessary. > >>> > >>> Signed-off-by: Nikolay Borisov <nborisov@xxxxxxxx> > >>> --- > >>> fs/btrfs/disk-io.c | 2 +- > >>> fs/btrfs/extent_io.c | 10 +++++----- > >>> fs/btrfs/extent_io.h | 2 +- > >>> 3 files changed, 7 insertions(+), 7 deletions(-) > >>> > >>> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c > >>> index 8a469f70d5ee..1c655be92690 100644 > >>> --- a/fs/btrfs/disk-io.c > >>> +++ b/fs/btrfs/disk-io.c > >>> @@ -4093,7 +4093,7 @@ void btrfs_mark_buffer_dirty(struct extent_buffer *buf) > >>> * enabled. Normal people shouldn't be marking dummy buffers as dirty > >>> * outside of the sanity tests. > >>> */ > >>> - if (unlikely(test_bit(EXTENT_BUFFER_DUMMY, &buf->bflags))) > >>> + if (unlikely(test_bit(EXTENT_BUFFER_PRIVATE, &buf->bflags))) > >> > >> This is going to be confusing. There's page Private bit, > >> PAGE_SET_PRIVATE2 and EXTENT_PAGE_PRIVATE, that are somehow logically > >> connected. > >> > >> I'd suggest EXTENT_BUFFER_CLONED or _UNMAPPED as it's created by > >> btrfs_clone_extent_buffer or used in the disconnected way (ie. without > >> the mapping). > > > > UNMAPPED looks good to me. > > (Or ANONYMOUS?) > > I'm more leaning towards UNMAPPED at this point. Ok, renamed it to EXTENT_BUFFER_UNMAPPED. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
