On Thu 22-03-12 13:25:37, Artem Bityutskiy wrote: > On Thu, 2012-03-22 at 11:33 +0100, Jan Kara wrote: > > > However, if there is _no_ journal, the 'write_super' is initialized, and > > > in many places the 's_dirt' flag is set, and thus VFS services seem to > > > be actively used. > > Which many places are you speaking about? Grep shows 4 places with > > sb->s_dirt = 1; > > Well, with 'ext4_mark_super_dirty()' there are still 6 or something > places. > > > You remove two of those in your cleanups so only > > __ext4_handle_dirty_super() remains. That is called from 3 (4 after your > > cleanups) places and they happen so rarely (during filesystem resize or > > when we start using some feature on the filesystem) that if you use > > sync_buffer() from all of them, it should be fine. > > But AFAIKC, the whole '__ext4_handle_dirty_super()' also falls-back to > marking the superblock as dirty if the file-system has no journal for > some reasons, right? Yes. And I wrote that if you do sync_buffer(EXT4_SB(sb)->s_sbh) instead of marking superblock dirty, it would be fine. > But I do not really understand what > 'ext4_handle_valid()' does. If I grep for 'ext4_handle_dirty_super()' - > there are many places places where it is used, and a few are obviously > for the superblocks. ext4_handle_valid() is false if and only if ext4 is in no-journal mode. If I grep for ext4_handle_dirty_super() I see: jack@quack:~/source/linux-fs/fs/ext4> grep "ext4_handle_dirty_super" *.c ext4_jbd2.c:int __ext4_handle_dirty_super(const char *where, unsigned int line, resize.c: err = ext4_handle_dirty_super(handle, sb); resize.c: ext4_handle_dirty_super(handle, sb); xattr.c: ext4_handle_dirty_super(handle, sb); So not really many cases... Honza -- Jan Kara <jack@xxxxxxx> SUSE Labs, CR -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
