[RFC PATCH 0/2] Initial support for badblock checking in xfs

[Vishal Verma]

These are early/RFC patches to add badblock support in xfs.

Patch 1 should be relatively straightforward - it adds a notifier chain
to badblocks that filesystems can register with.

Patch 2 is the beginnings of xfs support. So far, I have the notifier
registration and building the initial badblock list happening in
xfs_mountfs. The next steps (and I may need some help with this as I'm
no (x)fs developer :)) are to add this badblocks info to the reverse
mapping tree, and then to check for it before accessing the media.

Right now, this just prints the sector numbers/counts/{added, removed}
to the kernel log, for both the initial list, and subsequent notifier
hits.

While I've tested this with a fake pmem device using libnvdimm's
nfit_test framework, it should also work using badblock injection with
any block device:

# mkfs.xfs -f /dev/<device>
# echo 122 1 > /sys/block/<device>/badblocks
# echo 124 1 > /sys/block/<device>/badblocks
# mount -t xfs /dev/<device> /mnt
... in log:
[  +8.803776] XFS (pmem7): Mounting V4 Filesystem
[  +0.009633] XFS (pmem7): Ending clean mount
[  +0.001655] XFS (pmem7): got badblocks: sector 122, count 1
[  +0.002018] XFS (pmem7): got badblocks: sector 124, count 1

# echo 132 5 | > /sys/block/<device>/badblocks
[Jun16 18:56] XFS (pmem7): xfs badblock added sector 132 (count 5)

This is all based on Darrik's rmap work at:
https://github.com/djwong/linux/tree/rmap-reflink-devel

Since this is based on a v4.5-rc kernel, it lacks pmem support for
clearing badblocks on zeroing/writing, so those parts can't easily
be tested yet. The clearing work is in 4.7-rs kernels, and once we
rebase to that, that should also be available.


Vishal Verma (2):
  block, badblocks: add a notifier for badblocks
  xfs: initial/partial support for badblocks

 block/badblocks.c         |  79 +++++++++++++++++++++++++++++++++--
 fs/xfs/xfs_linux.h        |   1 +
 fs/xfs/xfs_mount.c        | 104 ++++++++++++++++++++++++++++++++++++++++++++++
 fs/xfs/xfs_mount.h        |   1 +
 include/linux/badblocks.h |  19 +++++++++
 5 files changed, 201 insertions(+), 3 deletions(-)

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2.5.5