linux.git/fs/btrfs, branch v4.13

Btrfs: fix blk_status_t/errno confusion

2017-08-24T15:19:02+00:00

This fixes several instances of blk_status_t and bare errno ints being
mixed up, some of which are real bugs.

In the normal case, 0 matches BLK_STS_OK, so we don't observe any
effects of the missing conversion, but in case of errors or passes
through the repair/retry paths, the errors get mixed up.

The changes were identified using 'sparse', we don't have reports of the
buggy behaviour.

Fixes: 4e4cbee93d56 ("block: switch bios to blk_status_t")
Signed-off-by: Omar Sandoval 
Reviewed-by: Liu Bo 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba

Merge branch 'for-4.13-part3' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

2017-07-28T19:26:59+00:00

Pull btrfs fixes from David Sterba:
 "Fixes addressing problems reported by users, and there's one more
  regression fix"

* 'for-4.13-part3' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: round down size diff when shrinking/growing device
  Btrfs: fix early ENOSPC due to delalloc
  btrfs: fix lockup in find_free_extent with read-only block groups
  Btrfs: fix dir item validation when replaying xattr deletes

btrfs: round down size diff when shrinking/growing device

2017-07-24T14:05:00+00:00

Further testing showed that the fix introduced in 7dfb8be11b5d ("btrfs:
Round down values which are written for total_bytes_size") was
insufficient and it could still lead to discrepancies between the
total_bytes in the super block and the device total bytes. So this patch
also ensures that the difference between old/new sizes when
shrinking/growing is also rounded down. This ensure that we won't be
subtracting/adding a non-sectorsize multiples to the superblock/device
total sizees.

Fixes: 7dfb8be11b5d ("btrfs: Round down values which are written for total_bytes_size")
Signed-off-by: Nikolay Borisov 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba

Btrfs: fix early ENOSPC due to delalloc

2017-07-24T14:04:26+00:00

If a lot of metadata is reserved for outstanding delayed allocations, we
rely on shrink_delalloc() to reclaim metadata space in order to fulfill
reservation tickets. However, shrink_delalloc() has a shortcut where if
it determines that space can be overcommitted, it will stop early. This
made sense before the ticketed enospc system, but now it means that
shrink_delalloc() will often not reclaim enough space to fulfill any
tickets, leading to an early ENOSPC. (Reservation tickets don't care
about being able to overcommit, they need every byte accounted for.)

Fix it by getting rid of the shortcut so that shrink_delalloc() reclaims
all of the metadata it is supposed to. This fixes early ENOSPCs we were
seeing when doing a btrfs receive to populate a new filesystem, as well
as early ENOSPCs Christoph saw when doing a big cp -r onto Btrfs.

Fixes: 957780eb2788 ("Btrfs: introduce ticketed enospc infrastructure")
Tested-by: Christoph Anton Mitterer 
Cc: stable@vger.kernel.org
Reviewed-by: Josef Bacik 
Signed-off-by: Omar Sandoval 
Signed-off-by: David Sterba

btrfs: fix lockup in find_free_extent with read-only block groups

2017-07-24T14:04:02+00:00

If we have a block group that is all of the following:
1) uncached in memory
2) is read-only
3) has a disk cache state that indicates we need to recreate the cache

AND the file system has enough free space fragmentation such that the
request for an extent of a given size can't be honored;

AND have a single CPU core;

AND it's the block group with the highest starting offset such that
there are no opportunities (like reading from disk) for the loop to
yield the CPU;

We can end up with a lockup.

The root cause is simple.  Once we're in the position that we've read in
all of the other block groups directly and none of those block groups
can honor the request, there are no more opportunities to sleep.  We end
up trying to start a caching thread which never gets run if we only have
one core.  This *should* present as a hung task waiting on the caching
thread to make some progress, but it doesn't.  Instead, it degrades into
a busy loop because of the placement of the read-only check.

During the first pass through the loop, block_group->cached will be set
to BTRFS_CACHE_STARTED and have_caching_bg will be set.  Then we hit the
read-only check and short circuit the loop.  We're not yet in
LOOP_CACHING_WAIT, so we skip that loop back before going through the
loop again for other raid groups.

Then we move to LOOP_CACHING_WAIT state.

During the this pass through the loop, ->cached will still be
BTRFS_CACHE_STARTED, which means it's not cached, so we'll enter
cache_block_group, do a lot of nothing, and return, and also set
have_caching_bg again.  Then we hit the read-only check and short circuit
the loop.  The same thing happens as before except now we DO trigger
the LOOP_CACHING_WAIT && have_caching_bg check and loop back up to the
top.  We do this forever.

There are two fixes in this patch since they address the same underlying
bug.

The first is to add a cond_resched to the end of the loop to ensure
that the caching thread always has an opportunity to run.  This will
fix the soft lockup issue, but find_free_extent will still loop doing
nothing until the thread has completed.

The second is to move the read-only check to the top of the loop.  We're
never going to return an allocation within a read-only block group so
we may as well skip it early.  The check for ->cached == BTRFS_CACHE_ERROR
would cause the same problem except that BTRFS_CACHE_ERROR is considered
a "done" state and we won't re-set have_caching_bg again.

Many thanks to Stephan Kulow  for his excellent help in
the testing process.

Signed-off-by: Jeff Mahoney 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba

Btrfs: fix dir item validation when replaying xattr deletes

2017-07-19T18:38:16+00:00

We were passing an incorrect slot number to the function that validates
directory items when we are replaying xattr deletes from a log tree. The
correct slot is stored at variable 'i' and not at 'path->slots[0]', so
the call to the validation function was only correct for the first
iteration of the loop, when 'i == path->slots[0]'.
After this fix, the fstest generic/066 passes again.

Fixes: 8ee8c2d62d5f ("btrfs: Verify dir_item in replay_xattr_deletes")
Signed-off-by: Filipe Manana 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba

Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2017-07-15T19:00:42+00:00

Pull ->s_options removal from Al Viro:
 "Preparations for fsmount/fsopen stuff (coming next cycle). Everything
  gets moved to explicit ->show_options(), killing ->s_options off +
  some cosmetic bits around fs/namespace.c and friends. Basically, the
  stuff needed to work with fsmount series with minimum of conflicts
  with other work.

  It's not strictly required for this merge window, but it would reduce
  the PITA during the coming cycle, so it would be nice to have those
  bits and pieces out of the way"

* 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  isofs: Fix isofs_show_options()
  VFS: Kill off s_options and helpers
  orangefs: Implement show_options
  9p: Implement show_options
  isofs: Implement show_options
  afs: Implement show_options
  affs: Implement show_options
  befs: Implement show_options
  spufs: Implement show_options
  bpf: Implement show_options
  ramfs: Implement show_options
  pstore: Implement show_options
  omfs: Implement show_options
  hugetlbfs: Implement show_options
  VFS: Don't use save/replace_mount_options if not using generic_show_options
  VFS: Provide empty name qstr
  VFS: Make get_filesystem() return the affected filesystem
  VFS: Clean up whitespace in fs/namespace.c and fs/super.c
  Provide a function to create a NUL-terminated string from unterminated data

Merge branch 'for-4.13-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

2017-07-15T05:55:52+00:00

Pull btrfs fixes from David Sterba:
 "We've identified and fixed a silent corruption (introduced by code in
  the first pull), a fixup after the blk_status_t merge and two fixes to
  incremental send that Filipe has been hunting for some time"

* 'for-4.13-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  Btrfs: fix unexpected return value of bio_readpage_error
  btrfs: btrfs_create_repair_bio never fails, skip error handling
  btrfs: cloned bios must not be iterated by bio_for_each_segment_all
  Btrfs: fix write corruption due to bio cloning on raid5/6
  Btrfs: incremental send, fix invalid memory access
  Btrfs: incremental send, fix invalid path for link commands

Btrfs: fix unexpected return value of bio_readpage_error

2017-07-14T18:42:37+00:00

With blk_status_t conversion (that are now present in master),
bio_readpage_error() may return 1 as now ->submit_bio_hook() may not set
%ret if it runs without problems.

This fixes that unexpected return value by changing
btrfs_check_repairable() to return a bool instead of updating %ret, and
patch is applicable to both codebases with and without blk_status_t.

Signed-off-by: Liu Bo 
Reviewed-by: Nikolay Borisov 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba

btrfs: btrfs_create_repair_bio never fails, skip error handling

2017-07-14T18:42:08+00:00

As the function uses the non-failing bio allocation, we can remove error
handling from the callers as well.

Signed-off-by: David Sterba 
Reviewed-by: Liu Bo 
Signed-off-by: David Sterba