lkml.org 
[lkml]   [2014]   [Dec]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH 2/8] swap: lock i_mutex for swap_writepage direct_IO
    On Tue, Dec 16, 2014 at 12:56:24AM -0800, Omar Sandoval wrote:
    > --- a/mm/swapfile.c
    > +++ b/mm/swapfile.c
    > @@ -1728,6 +1728,9 @@ static int setup_swap_extents(struct swap_info_struct *sis, sector_t *span)
    > }
    >
    > if (mapping->a_ops->swap_activate) {
    > + if (!mapping->a_ops->direct_IO)
    > + return -EINVAL;
    > + swap_file->f_flags |= O_DIRECT;
    > ret = mapping->a_ops->swap_activate(sis, swap_file, span);
    > if (!ret) {
    > sis->flags |= SWP_FILE;

    This needs to hold swap_file->f_lock, but otherwise looks good.

    > This seems to be more or less equivalent to doing a fcntl(F_SETFL) to
    > add the O_DIRECT flag to swap_file (which is a struct file *). Swapoff
    > calls filp_close on swap_file, so I don't see why it's necessary to
    > clear the flag.

    filp_lose doesn't nessecarily destroy the file structure, there might be
    other reference to it, e.g. from dup() or descriptor passing.


    \
     
     \ /
      Last update: 2014-12-17 09:41    [W:2.997 / U:0.808 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site