src/patches/suse-2.6.27.39/patches.fixes/0001-md-Relax-minimum-size-restrictions-on-chunk_size.patch

   1 From 4bbf3771ca40d0aaec8316d0e7476b16010288e5 Mon Sep 17 00:00:00 2001
   2 From: NeilBrown <neilb@suse.de>
   3 Date: Mon, 13 Oct 2008 11:55:12 +1100
   4 Subject: [PATCH] md: Relax minimum size restrictions on chunk_size.
   5
   6 Currently, the 'chunk_size' of an array must be at-least PAGE_SIZE.
   7
   8 This makes moving an array to a machine with a larger PAGE_SIZE, or
   9 changing the kernel to use a larger PAGE_SIZE, can stop an array from
  10 working.
  11
  12 For RAID10 and RAID4/5/6, this is non-trivial to fix as the resync
  13 process works on whole pages at a time, and assumes them to be wholly
  14 within a stripe.  For other raid personalities, this restriction is
  15 not needed at all and can be dropped.
  16
  17 So remove the test on chunk_size from common can, and add it in just
  18 the places where it is needed: raid10 and raid4/5/6.
  19
  20 Signed-off-by: NeilBrown <neilb@suse.de>
  21 ---
  22  drivers/md/md.c     |   12 +-----------
  23  drivers/md/raid10.c |    5 +++--
  24  drivers/md/raid5.c  |    7 +++++++
  25  3 files changed, 11 insertions(+), 13 deletions(-)
  26
  27 --- linux-2.6.27-SLE11_BRANCH.orig/drivers/md/md.c
  28 +++ linux-2.6.27-SLE11_BRANCH/drivers/md/md.c
  29 @@ -3580,22 +3580,12 @@ static int do_md_run(mddev_t * mddev)
  30                         return -EINVAL;
  31                 }
  32                 /*
  33 -                * chunk-size has to be a power of 2 and multiples of PAGE_SIZE
  34 +                * chunk-size has to be a power of 2
  35                  */
  36                 if ( (1 << ffz(~chunk_size)) != chunk_size) {
  37                         printk(KERN_ERR "chunk_size of %d not valid\n", chunk_size);
  38                         return -EINVAL;
  39                 }
  40 -               if (chunk_size < PAGE_SIZE) {
  41 -                       if (mddev->level != 0 && mddev->level != 1) {
  42 -                       printk(KERN_ERR "too small chunk_size: %d < %ld\n",
  43 -                               chunk_size, PAGE_SIZE);
  44 -                       return -EINVAL;
  45 -                       } else {
  46 -                               printk(KERN_ERR "too small chunk_size: %d < %ld, but continuing anyway on raid%d. Good luck!\n",
  47 -                                       chunk_size, PAGE_SIZE, mddev->level);
  48 -                       }
  49 -               }
  50
  51                 /* devices must have minimum size of one chunk */
  52                 rdev_for_each(rdev, tmp, mddev) {
  53 --- linux-2.6.27-SLE11_BRANCH.orig/drivers/md/raid10.c
  54 +++ linux-2.6.27-SLE11_BRANCH/drivers/md/raid10.c
  55 @@ -2025,8 +2025,9 @@ static int run(mddev_t *mddev)
  56         int nc, fc, fo;
  57         sector_t stride, size;
  58
  59 -       if (mddev->chunk_size == 0) {
  60 -               printk(KERN_ERR "md/raid10: non-zero chunk size required.\n");
  61 +       if (mddev->chunk_size < PAGE_SIZE) {
  62 +               printk(KERN_ERR "md/raid10: chunk size must be "
  63 +                      "at least PAGE_SIZE(%ld).\n", PAGE_SIZE);
  64                 return -EINVAL;
  65         }
  66
  67 --- linux-2.6.27-SLE11_BRANCH.orig/drivers/md/raid5.c
  68 +++ linux-2.6.27-SLE11_BRANCH/drivers/md/raid5.c
  69 @@ -4010,6 +4010,13 @@ static int run(mddev_t *mddev)
  70                 return -EIO;
  71         }
  72
  73 +       if (mddev->chunk_size < PAGE_SIZE) {
  74 +               printk(KERN_ERR "md/raid5: chunk_size must be at least "
  75 +                      "PAGE_SIZE but %d < %ld\n",
  76 +                      mddev->chunk_size, PAGE_SIZE);
  77 +               return -EINVAL;
  78 +       }
  79 +
  80         if (mddev->reshape_position != MaxSector) {
  81                 /* Check that we can continue the reshape.
  82                  * Currently only disks can change, it must