linux.git/fs/btrfs, branch v3.14

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs

2014-02-16T19:05:27+00:00

Pull btrfs fixes from Chris Mason:
 "We have a small collection of fixes in my for-linus branch.

  The big thing that stands out is a revert of a new ioctl.  Users
  haven't shipped yet in btrfs-progs, and Dave Sterba found a better way
  to export the information"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  Btrfs: use right clone root offset for compressed extents
  btrfs: fix null pointer deference at btrfs_sysfs_add_one+0x105
  Btrfs: unset DCACHE_DISCONNECTED when mounting default subvol
  Btrfs: fix max_inline mount option
  Btrfs: fix a lockdep warning when cleaning up aborted transaction
  Revert "btrfs: add ioctl to export size of global metadata reservation"

Btrfs: use right clone root offset for compressed extents

2014-02-15T16:04:27+00:00

For non compressed extents, iterate_extent_inodes() gives us offsets
that take into account the data offset from the file extent items, while
for compressed extents it doesn't. Therefore we have to adjust them before
placing them in a send clone instruction. Not doing this adjustment leads to
the receiving end requesting for a wrong a file range to the clone ioctl,
which results in different file content from the one in the original send
root.

Issue reproducible with the following excerpt from the test I made for
xfstests:

  _scratch_mkfs
  _scratch_mount "-o compress-force=lzo"

  $XFS_IO_PROG -f -c "truncate 118811" $SCRATCH_MNT/foo
  $XFS_IO_PROG -c "pwrite -S 0x0d -b 39987 92267 39987" $SCRATCH_MNT/foo

  $BTRFS_UTIL_PROG subvolume snapshot -r $SCRATCH_MNT $SCRATCH_MNT/mysnap1

  $XFS_IO_PROG -c "pwrite -S 0x3e -b 80000 200000 80000" $SCRATCH_MNT/foo
  $BTRFS_UTIL_PROG filesystem sync $SCRATCH_MNT
  $XFS_IO_PROG -c "pwrite -S 0xdc -b 10000 250000 10000" $SCRATCH_MNT/foo
  $XFS_IO_PROG -c "pwrite -S 0xff -b 10000 300000 10000" $SCRATCH_MNT/foo

  # will be used for incremental send to be able to issue clone operations
  $BTRFS_UTIL_PROG subvolume snapshot -r $SCRATCH_MNT $SCRATCH_MNT/clones_snap

  $BTRFS_UTIL_PROG subvolume snapshot -r $SCRATCH_MNT $SCRATCH_MNT/mysnap2

  $FSSUM_PROG -A -f -w $tmp/1.fssum $SCRATCH_MNT/mysnap1
  $FSSUM_PROG -A -f -w $tmp/2.fssum -x $SCRATCH_MNT/mysnap2/mysnap1 \
      -x $SCRATCH_MNT/mysnap2/clones_snap $SCRATCH_MNT/mysnap2
  $FSSUM_PROG -A -f -w $tmp/clones.fssum $SCRATCH_MNT/clones_snap \
      -x $SCRATCH_MNT/clones_snap/mysnap1 -x $SCRATCH_MNT/clones_snap/mysnap2

  $BTRFS_UTIL_PROG send $SCRATCH_MNT/mysnap1 -f $tmp/1.snap
  $BTRFS_UTIL_PROG send $SCRATCH_MNT/clones_snap -f $tmp/clones.snap
  $BTRFS_UTIL_PROG send -p $SCRATCH_MNT/mysnap1 \
      -c $SCRATCH_MNT/clones_snap $SCRATCH_MNT/mysnap2 -f $tmp/2.snap

  _scratch_unmount
  _scratch_mkfs
  _scratch_mount

  $BTRFS_UTIL_PROG receive $SCRATCH_MNT -f $tmp/1.snap
  $FSSUM_PROG -r $tmp/1.fssum $SCRATCH_MNT/mysnap1 2>> $seqres.full

  $BTRFS_UTIL_PROG receive $SCRATCH_MNT -f $tmp/clones.snap
  $FSSUM_PROG -r $tmp/clones.fssum $SCRATCH_MNT/clones_snap 2>> $seqres.full

  $BTRFS_UTIL_PROG receive $SCRATCH_MNT -f $tmp/2.snap
  $FSSUM_PROG -r $tmp/2.fssum $SCRATCH_MNT/mysnap2 2>> $seqres.full

Signed-off-by: Filipe David Borba Manana 
Signed-off-by: Chris Mason

btrfs: fix null pointer deference at btrfs_sysfs_add_one+0x105

2014-02-15T16:03:09+00:00

bdev is null when disk has disappeared and mounted with
the degrade option

stack trace
---------
btrfs_sysfs_add_one+0x105/0x1c0 [btrfs]
open_ctree+0x15f3/0x1fe0 [btrfs]
btrfs_mount+0x5db/0x790 [btrfs]
? alloc_pages_current+0xa4/0x160
mount_fs+0x34/0x1b0
vfs_kern_mount+0x62/0xf0
do_mount+0x22e/0xa80
? __get_free_pages+0x9/0x40
? copy_mount_options+0x31/0x170
SyS_mount+0x7e/0xc0
system_call_fastpath+0x16/0x1b
---------

reproducer:
-------
mkfs.btrfs -draid1 -mraid1 /dev/sdc /dev/sdd
(detach a disk)
devmgt detach /dev/sdc [1]
mount -o degrade /dev/sdd /btrfs
-------

[1] github.com/anajain/devmgt.git

Signed-off-by: Anand Jain 
Tested-by: Hidetoshi Seto 
Signed-off-by: Chris Mason

Btrfs: unset DCACHE_DISCONNECTED when mounting default subvol

2014-02-14T21:44:32+00:00

A user was running into errors from an NFS export of a subvolume that had a
default subvol set.  When we mount a default subvol we will use d_obtain_alias()
to find an existing dentry for the subvolume in the case that the root subvol
has already been mounted, or a dummy one is allocated in the case that the root
subvol has not already been mounted.  This allows us to connect the dentry later
on if we wander into the path.  However if we don't ever wander into the path we
will keep DCACHE_DISCONNECTED set for a long time, which angers NFS.  It doesn't
appear to cause any problems but it is annoying nonetheless, so simply unset
DCACHE_DISCONNECTED in the get_default_root case and switch btrfs_lookup() to
use d_materialise_unique() instead which will make everything play nicely
together and reconnect stuff if we wander into the defaul subvol path from a
different way.  With this patch I'm no longer getting the NFS errors when
exporting a volume that has been mounted with a default subvol set.  Thanks,

cc: bfields@fieldses.org
cc: ebiederm@xmission.com
Signed-off-by: Josef Bacik 
Acked-by: "Eric W. Biederman" 
Signed-off-by: Chris Mason

Btrfs: fix max_inline mount option

2014-02-14T21:44:32+00:00

Currently, the only mount option for max_inline that has any effect is
max_inline=0.  Any other value that is supplied to max_inline will be
adjusted to a minimum of 4k.  Since max_inline has an effective maximum
of ~3900 bytes due to page size limitations, the current behaviour
only has meaning for max_inline=0.

This patch will allow the the max_inline mount option to accept non-zero
values as indicated in the documentation.

Signed-off-by: Mitch Harder 
Signed-off-by: Chris Mason

Btrfs: fix a lockdep warning when cleaning up aborted transaction

2014-02-14T21:44:32+00:00

Given now we have 2 spinlock for management of delayed refs,
CONFIG_DEBUG_SPINLOCK=y helped me find this,

[ 4723.413809] BUG: spinlock wrong CPU on CPU#1, btrfs-transacti/2258
[ 4723.414882]  lock: 0xffff880048377670, .magic: dead4ead, .owner: btrfs-transacti/2258, .owner_cpu: 2
[ 4723.417146] CPU: 1 PID: 2258 Comm: btrfs-transacti Tainted: G        W  O 3.12.0+ #4
[ 4723.421321] Call Trace:
[ 4723.421872]  [] dump_stack+0x54/0x74
[ 4723.422753]  [] spin_dump+0x8c/0x91
[ 4723.424979]  [] spin_bug+0x21/0x26
[ 4723.425846]  [] do_raw_spin_unlock+0x66/0x90
[ 4723.434424]  [] _raw_spin_unlock+0x27/0x40
[ 4723.438747]  [] btrfs_cleanup_one_transaction+0x35e/0x710 [btrfs]
[ 4723.443321]  [] btrfs_cleanup_transaction+0x104/0x570 [btrfs]
[ 4723.444692]  [] ? trace_hardirqs_on_caller+0xfd/0x1c0
[ 4723.450336]  [] ? trace_hardirqs_on+0xd/0x10
[ 4723.451332]  [] transaction_kthread+0x22e/0x270 [btrfs]
[ 4723.452543]  [] ? btrfs_cleanup_transaction+0x570/0x570 [btrfs]
[ 4723.457833]  [] kthread+0xea/0xf0
[ 4723.458990]  [] ? kthread_create_on_node+0x140/0x140
[ 4723.460133]  [] ret_from_fork+0x7c/0xb0
[ 4723.460865]  [] ? kthread_create_on_node+0x140/0x140
[ 4723.496521] ------------[ cut here ]------------

----------------------------------------------------------------------

The reason is that we get to call cond_resched_lock(&head_ref->lock) while
still holding @delayed_refs->lock.

So it's different with __btrfs_run_delayed_refs(), where we do drop-acquire
dance before and after actually processing delayed refs.

Here we don't drop the lock, others are not able to add new delayed refs to
head_ref, so cond_resched_lock(&head_ref->lock) is not necessary here.

Signed-off-by: Liu Bo 
Signed-off-by: Chris Mason

Revert "btrfs: add ioctl to export size of global metadata reservation"

2014-02-14T21:42:13+00:00

This reverts commit 01e219e8069516cdb98594d417b8bb8d906ed30d.

David Sterba found a different way to provide these features without adding a new
ioctl.  We haven't released any progs with this ioctl yet, so I'm taking this out
for now until we finalize things.

Signed-off-by: Chris Mason 
Signed-off-by: David Sterba 
CC: Jeff Mahoney

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs

2014-02-09T19:12:26+00:00

Pull btrfs fixes from Chris Mason:
 "This is a small collection of fixes"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  Btrfs: fix data corruption when reading/updating compressed extents
  Btrfs: don't loop forever if we can't run because of the tree mod log
  btrfs: reserve no transaction units in btrfs_ioctl_set_features
  btrfs: commit transaction after setting label and features
  Btrfs: fix assert screwup for the pending move stuff

Btrfs: fix data corruption when reading/updating compressed extents

2014-02-09T01:57:15+00:00

When using a mix of compressed file extents and prealloc extents, it
is possible to fill a page of a file with random, garbage data from
some unrelated previous use of the page, instead of a sequence of zeroes.

A simple sequence of steps to get into such case, taken from the test
case I made for xfstests, is:

   _scratch_mkfs
   _scratch_mount "-o compress-force=lzo"
   $XFS_IO_PROG -f -c "pwrite -S 0x06 -b 18670 266978 18670" $SCRATCH_MNT/foobar
   $XFS_IO_PROG -c "falloc 26450 665194" $SCRATCH_MNT/foobar
   $XFS_IO_PROG -c "truncate 542872" $SCRATCH_MNT/foobar
   $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foobar

This results in the following file items in the fs tree:

   item 4 key (257 INODE_ITEM 0) itemoff 15879 itemsize 160
       inode generation 6 transid 6 size 542872 block group 0 mode 100600
   item 5 key (257 INODE_REF 256) itemoff 15863 itemsize 16
       inode ref index 2 namelen 6 name: foobar
   item 6 key (257 EXTENT_DATA 0) itemoff 15810 itemsize 53
       extent data disk byte 0 nr 0 gen 6
       extent data offset 0 nr 24576 ram 266240
       extent compression 0
   item 7 key (257 EXTENT_DATA 24576) itemoff 15757 itemsize 53
       prealloc data disk byte 12849152 nr 241664 gen 6
       prealloc data offset 0 nr 241664
   item 8 key (257 EXTENT_DATA 266240) itemoff 15704 itemsize 53
       extent data disk byte 12845056 nr 4096 gen 6
       extent data offset 0 nr 20480 ram 20480
       extent compression 2
   item 9 key (257 EXTENT_DATA 286720) itemoff 15651 itemsize 53
       prealloc data disk byte 13090816 nr 405504 gen 6
       prealloc data offset 0 nr 258048

The on disk extent at offset 266240 (which corresponds to 1 single disk block),
contains 5 compressed chunks of file data. Each of the first 4 compress 4096
bytes of file data, while the last one only compresses 3024 bytes of file data.
Therefore a read into the file region [285648 ; 286720[ (length = 4096 - 3024 =
1072 bytes) should always return zeroes (our next extent is a prealloc one).

The solution here is the compression code path to zero the remaining (untouched)
bytes of the last page it uncompressed data into, as the information about how
much space the file data consumes in the last page is not known in the upper layer
fs/btrfs/extent_io.c:__do_readpage(). In __do_readpage we were correctly zeroing
the remainder of the page but only if it corresponds to the last page of the inode
and if the inode's size is not a multiple of the page size.

This would cause not only returning random data on reads, but also permanently
storing random data when updating parts of the region that should be zeroed.
For the example above, it means updating a single byte in the region [285648 ; 286720[
would store that byte correctly but also store random data on disk.

A test case for xfstests follows soon.

Signed-off-by: Filipe David Borba Manana 
Signed-off-by: Chris Mason

Btrfs: don't loop forever if we can't run because of the tree mod log

2014-02-09T01:57:15+00:00

A user reported a 100% cpu hang with my new delayed ref code.  Turns out I
forgot to increase the count check when we can't run a delayed ref because of
the tree mod log.  If we can't run any delayed refs during this there is no
point in continuing to look, and we need to break out.  Thanks,

Signed-off-by: Josef Bacik 
Signed-off-by: Chris Mason