lkml.org 
[lkml]   [2010]   [Sep]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH 6/7 v3] overlay: hybrid overlay filesystem prototype
    On Mon, Sep 20, 2010 at 08:04:10PM +0200, Miklos Szeredi wrote:
    > From: Miklos Szeredi <mszeredi@suse.cz>
    >
    > This overlay filesystem is a hybrid of entirely filesystem based
    > (unionfs, aufs) and entierly VFS based (union mounts) solutions.

    [...]

    > +static int ovl_copy_up_data(struct path *old, struct path *new, loff_t len)
    > +{
    > + struct file *old_file;
    > + struct file *new_file;
    > + int error = 0;
    > +
    > + if (len == 0)
    > + return 0;
    > +
    > + old_file = path_open(old, O_RDONLY);
    > + if (IS_ERR(old_file))
    > + return PTR_ERR(old_file);
    > +
    > + new_file = path_open(new, O_WRONLY);
    > + if (IS_ERR(new_file)) {
    > + error = PTR_ERR(new_file);
    > + goto out_fput;
    > + }
    > +
    > + /* FIXME: copy up sparse files efficiently */
    > + while (len) {
    > + loff_t offset = new_file->f_pos;
    > + size_t this_len = OVL_COPY_UP_CHUNK_SIZE;
    > + long bytes;
    > +
    > + if (len < this_len)
    > + this_len = len;
    > +
    > + if (signal_pending_state(TASK_KILLABLE, current))
    > + return -EINTR;
    > +
    > + bytes = do_splice_direct(old_file, &offset, new_file, this_len,
    > + SPLICE_F_MOVE);

    Interruptible copyup is good. But it looks like splice setup is kind
    of heavyweight and we should do it as seldom as possible.

    What about implementing splice flag SPLICE_F_INTERRUPTIBLE instead?

    -VAL


    \
     
     \ /
      Last update: 2010-09-23 01:23    [from the cache]
    ©2003-2011 Jasper Spaans