• Nick Piggin's avatar
    [PATCH] mm: non syncing lock_page() · db37648c
    Nick Piggin authored
    
    
    lock_page needs the caller to have a reference on the page->mapping inode
    due to sync_page, ergo set_page_dirty_lock is obviously buggy according to
    its comments.
    
    Solve it by introducing a new lock_page_nosync which does not do a sync_page.
    
    akpm: unpleasant solution to an unpleasant problem.  If it goes wrong it could
    cause great slowdowns while the lock_page() caller waits for kblockd to
    perform the unplug.  And if a filesystem has special sync_page() requirements
    (none presently do), permanent hangs are possible.
    
    otoh, set_page_dirty_lock() is usually (always?) called against userspace
    pages.  They are always up-to-date, so there shouldn't be any pending read I/O
    against these pages.
    Signed-off-by: default avatarNick Piggin <npiggin@suse.de>
    Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
    db37648c