[PATCH v4] xfs: probe data buffer from page cache for unwritten extents

[Mark Tinguely]

On 07/20/12 03:28, Jeff Liu wrote:
> Hi All,
>
> According to Mark and Christoph's comments for v3, except optimizing xfs_seek_data() with unwritten extents
> probing, the xfs_seek_hole() is also refined to that in this version.
>
>

Just some feedback.

Test program fragment:

         ret = do_fallocate(fd, 512*1024, 256*1024, 0);
         if (ret < 0)
                 goto out;
         pwrite(fd, buf, 4096, 1024*516);
         lseek(fd, 800*1024, SEEK_SET);
         ret = write(fd, buf, bufsz);
         if (ret < 0)
                 goto out;

Output:

HOLE/DATA at 512K 786432 / 528384   <- undiscovered hole here
HOLE/DATA at 516K 786432 / 528384   <- okay, data but we should
                                         return next page as hole.
HOLE/DATA at 520K 532480 / 819200   <- hole is discovered because
                                        there is no trailing data

--Mark.