Commit Graph

550 Commits

Author SHA1 Message Date
David Sterba
31388ab2ed btrfs: fix rcu warning during device replace
The test btrfs/011 triggers a rcu warning
Reviewed-by: Anand Jain <anand.jain@oracle.com>

===============================
[ INFO: suspicious RCU usage. ]
4.4.0-rc1-default+ #286 Tainted: G        W
-------------------------------
fs/btrfs/volumes.c:1977 suspicious rcu_dereference_check() usage!

other info that might help us debug this:

rcu_scheduler_active = 1, debug_locks = 0
4 locks held by btrfs/28786:

0:  (&fs_info->dev_replace.lock_finishing_cancel_unmount){+.+...}, at: [<ffffffffa00bc785>] btrfs_dev_replace_finishing+0x45/0xa00 [btrfs]
1:  (uuid_mutex){+.+.+.}, at: [<ffffffffa00bc84f>] btrfs_dev_replace_finishing+0x10f/0xa00 [btrfs]
2:  (&fs_devs->device_list_mutex){+.+.+.}, at: [<ffffffffa00bc868>] btrfs_dev_replace_finishing+0x128/0xa00 [btrfs]
3:  (&fs_info->chunk_mutex){+.+...}, at: [<ffffffffa00bc87d>] btrfs_dev_replace_finishing+0x13d/0xa00 [btrfs]

stack backtrace:
CPU: 0 PID: 28786 Comm: btrfs Tainted: G        W       4.4.0-rc1-default+ #286
Hardware name: Intel Corporation SandyBridge Platform/To be filled by O.E.M., BIOS ASNBCPT1.86C.0031.B00.1006301607 06/30/2010
0000000000000001 ffff8800a07dfb48 ffffffff8141d47b 0000000000000001
0000000000000001 0000000000000000 ffff8801464a4f00 ffff8800a07dfb78
ffffffff810cd883 ffff880146eb9400 ffff8800a3698600 ffff8800a33fe220
Call Trace:
[<ffffffff8141d47b>] dump_stack+0x4f/0x74
[<ffffffff810cd883>] lockdep_rcu_suspicious+0x103/0x140
[<ffffffffa0071261>] btrfs_rm_dev_replace_remove_srcdev+0x111/0x130 [btrfs]
[<ffffffff810d354d>] ? trace_hardirqs_on+0xd/0x10
[<ffffffff81449536>] ? __percpu_counter_sum+0x66/0x80
[<ffffffffa00bcc15>] btrfs_dev_replace_finishing+0x4d5/0xa00 [btrfs]
[<ffffffffa00bc96e>] ? btrfs_dev_replace_finishing+0x22e/0xa00 [btrfs]
[<ffffffffa00a8795>] ? btrfs_scrub_dev+0x415/0x6d0 [btrfs]
[<ffffffffa003ea69>] ? btrfs_start_transaction+0x9/0x20 [btrfs]
[<ffffffffa00bda79>] btrfs_dev_replace_start+0x339/0x590 [btrfs]
[<ffffffff81196aa5>] ? __might_fault+0x95/0xa0
[<ffffffffa0078638>] btrfs_ioctl_dev_replace+0x118/0x160 [btrfs]
[<ffffffff811409c6>] ? stack_trace_call+0x46/0x70
[<ffffffffa007c914>] ? btrfs_ioctl+0x24/0x1770 [btrfs]
[<ffffffffa007ce43>] btrfs_ioctl+0x553/0x1770 [btrfs]
[<ffffffff811409c6>] ? stack_trace_call+0x46/0x70
[<ffffffff811d6eb1>] ? do_vfs_ioctl+0x21/0x5a0
[<ffffffff811d6f1c>] do_vfs_ioctl+0x8c/0x5a0
[<ffffffff811e3336>] ? __fget_light+0x86/0xb0
[<ffffffff811e3369>] ? __fdget+0x9/0x20
[<ffffffff811d7451>] ? SyS_ioctl+0x21/0x80
[<ffffffff811d7483>] SyS_ioctl+0x53/0x80
[<ffffffff81b1efd7>] entry_SYSCALL_64_fastpath+0x12/0x6f

This is because of unprotected use of rcu_dereference in
btrfs_scratch_superblocks. We can't add rcu locks around the whole
function because we read the superblock.

The fix will use the rcu string buffer directly without the rcu locking.
Thi is safe as the device will not go away in the meantime. We're
holding the device list mutexes.

Restructuring the code to narrow down the rcu section turned out to be
impossible, we need to call filp_open (through update_dev_time) on the
buffer and this could call kmalloc/__might_sleep. We could call kstrdup
with GFP_ATOMIC but it's not absolutely necessary.

Fixes: 12b1c2637b (Btrfs: enhance btrfs_scratch_superblock to scratch all superblocks)
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-11-25 05:19:51 -08:00
Filipe Manana
7fd01182d1 Btrfs: fix the number of transaction units needed to remove a block group
We were using only 1 transaction unit when attempting to delete an unused
block group but in reality we need 3 + N units, where N corresponds to the
number of stripes. We were accounting only for the addition of the orphan
item (for the block group's free space cache inode) but we were not
accounting that we need to delete one block group item from the extent
tree, one free space item from the tree of tree roots and N device extent
items from the device tree.

While one unit is not enough, it worked most of the time because for each
single unit we are too pessimistic and assume an entire tree path, with
the highest possible heigth (8), needs to be COWed with eventual node
splits at every possible level in the tree, so there was usually enough
reserved space for removing all the items and adding the orphan item.

However after adding the orphan item, writepages() can by called by the VM
subsystem against the btree inode when we are under memory pressure, which
causes writeback to start for the nodes we COWed before, this forces the
operation to remove the free space item to COW again some (or all of) the
same nodes (in the tree of tree roots). Even without writepages() being
called, we could fail with ENOSPC because these items are located in
multiple trees and one of them might have a higher heigth and require
node/leaf splits at many levels, exhausting all the reserved space before
removing all the items and adding the orphan.

In the kernel 4.0 release, commit 3d84be7991 ("Btrfs: fix BUG_ON in
btrfs_orphan_add() when delete unused block group"), we attempted to fix
a BUG_ON due to ENOSPC when trying to add the orphan item by making the
cleaner kthread reserve one transaction unit before attempting to remove
the block group, but this was not enough. We had a couple user reports
still hitting the same BUG_ON after 4.0, like Stefan Priebe's report on
a 4.2-rc6 kernel for example:

    http://www.spinics.net/lists/linux-btrfs/msg46070.html

So fix this by reserving all the necessary units of metadata.

Reported-by: Stefan Priebe <s.priebe@profihost.ag>
Fixes: 3d84be7991 ("Btrfs: fix BUG_ON in btrfs_orphan_add() when delete unused block group")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-11-25 05:19:50 -08:00
Filipe Manana
8eab77ff16 Btrfs: use global reserve when deleting unused block group after ENOSPC
It's possible to reach a state where the cleaner kthread isn't able to
start a transaction to delete an unused block group due to lack of enough
free metadata space and due to lack of unallocated device space to allocate
a new metadata block group as well. If this happens try to use space from
the global block group reserve just like we do for unlink operations, so
that we don't reach a permanent state where starting a transaction for
filesystem operations (file creation, renames, etc) keeps failing with
-ENOSPC. Such an unfortunate state was observed on a machine where over
a dozen unused data block groups existed and the cleaner kthread was
failing to delete them due to ENOSPC error when attempting to start a
transaction, and even running balance with a -dusage=0 filter failed with
ENOSPC as well. Also unmounting and mounting again the filesystem didn't
help. Allowing the cleaner kthread to use the global block reserve to
delete the unused data block groups fixed the problem.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-11-25 05:19:50 -08:00
Zhao Lei
2c9fe83552 btrfs: Fix lost-data-profile caused by balance bg
Reproduce:
 (In integration-4.3 branch)

 TEST_DEV=(/dev/vdg /dev/vdh)
 TEST_DIR=/mnt/tmp

 umount "$TEST_DEV" >/dev/null
 mkfs.btrfs -f -d raid1 "${TEST_DEV[@]}"

 mount -o nospace_cache "$TEST_DEV" "$TEST_DIR"
 btrfs balance start -dusage=0 $TEST_DIR
 btrfs filesystem usage $TEST_DIR

 dd if=/dev/zero of="$TEST_DIR"/file count=100
 btrfs filesystem usage $TEST_DIR

Result:
 We can see "no data chunk" in first "btrfs filesystem usage":
 # btrfs filesystem usage $TEST_DIR
 Overall:
    ...
 Metadata,single: Size:8.00MiB, Used:0.00B
    /dev/vdg        8.00MiB
 Metadata,RAID1: Size:122.88MiB, Used:112.00KiB
    /dev/vdg      122.88MiB
    /dev/vdh      122.88MiB
 System,single: Size:4.00MiB, Used:0.00B
    /dev/vdg        4.00MiB
 System,RAID1: Size:8.00MiB, Used:16.00KiB
    /dev/vdg        8.00MiB
    /dev/vdh        8.00MiB
 Unallocated:
    /dev/vdg        1.06GiB
    /dev/vdh        1.07GiB

 And "data chunks changed from raid1 to single" in second
 "btrfs filesystem usage":
 # btrfs filesystem usage $TEST_DIR
 Overall:
    ...
 Data,single: Size:256.00MiB, Used:0.00B
    /dev/vdh      256.00MiB
 Metadata,single: Size:8.00MiB, Used:0.00B
    /dev/vdg        8.00MiB
 Metadata,RAID1: Size:122.88MiB, Used:112.00KiB
    /dev/vdg      122.88MiB
    /dev/vdh      122.88MiB
 System,single: Size:4.00MiB, Used:0.00B
    /dev/vdg        4.00MiB
 System,RAID1: Size:8.00MiB, Used:16.00KiB
    /dev/vdg        8.00MiB
    /dev/vdh        8.00MiB
 Unallocated:
    /dev/vdg        1.06GiB
    /dev/vdh      841.92MiB

Reason:
 btrfs balance delete last data chunk in case of no data in
 the filesystem, then we can see "no data chunk" by "fi usage"
 command.

 And when we do write operation to fs, the only available data
 profile is 0x0, result is all new chunks are allocated single type.

Fix:
 Allocate a data chunk explicitly to ensure we don't lose the
 raid profile for data.

Test:
 Test by above script, and confirmed the logic by debug output.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-11-10 19:27:20 -08:00
David Sterba
bc3094673f btrfs: extend balance filter usage to take minimum and maximum
Similar to the 'limit' filter, we can enhance the 'usage' filter to
accept a range. The change is backward compatible, the range is applied
only in connection with the BTRFS_BALANCE_ARGS_USAGE_RANGE flag.

We don't have a usecase yet, the current syntax has been sufficient. The
enhancement should provide parity with other range-like filters.

Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-10-26 19:38:30 -07:00
Gabríel Arthúr Pétursson
dee32d0ac3 btrfs: add balance filter for stripes
Balance block groups which have the given number of stripes, defined by
a range min..max. This is useful to selectively rebalance only chunks
that do not span enough devices, applies to RAID0/10/5/6.

Signed-off-by: Gabríel Arthúr Pétursson <gabriel@system.is>
[ renamed bargs members, added to the UAPI, wrote the changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>

Signed-off-by: Chris Mason <clm@fb.com>
2015-10-26 19:38:29 -07:00
David Sterba
12907fc798 btrfs: extend balance filter limit to take minimum and maximum
The 'limit' filter is underdesigned, it should have been a range for
[min,max], with some relaxed semantics when one of the bounds is
missing. Besides that, using a full u64 for a single value is a waste of
bytes.

Let's fix both by extending the use of the u64 bytes for the [min,max]
range. This can be done in a backward compatible way, the range will be
interpreted only if the appropriate flag is set
(BTRFS_BALANCE_ARGS_LIMIT_RANGE).

Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-10-26 19:38:28 -07:00
Josef Bacik
3204d33cda Btrfs: add a flags field to btrfs_transaction
I want to set some per transaction flags, so instead of adding yet another int
lets just convert the current two int indicators to flags and add a flags field
for future use.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-10-21 18:51:45 -07:00
Chris Mason
a0d58e48db Merge branch 'cleanups/for-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux into for-linus-4.4 2015-10-21 18:21:40 -07:00
Alexandru Moise
bdcd3c97d1 btrfs: cleanup btrfs_balance profile validity checks
Improve readability by generalizing the profile validity checks.

Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: Alexandru Moise <00moses.alexander00@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2015-10-21 18:28:48 +02:00
Zhao Lei
8789f4fe60 btrfs: use btrfs_raid_array for btrfs_get_num_tolerated_disk_barrier_failures()
btrfs_raid_array[] is used to define all raid attributes, use it
to get tolerated_failures in btrfs_get_num_tolerated_disk_barrier_failures(),
instead of complex condition in function.

It can make code simple and auto-support other possible raid-type in
future.

Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2015-10-21 18:28:48 +02:00
Zhao Lei
af90204750 btrfs: Move btrfs_raid_array to public
This array is used to record attributes of each raid type,
make it public, and many functions will benifit with this array.

For example, num_tolerated_disk_barrier_failures(), we can
avoid complex conditions in this function, and get raid attribute
simply by accessing above array.

It can also make code logic simple, reduce duplication code, and
increase maintainability.

Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2015-10-21 18:28:48 +02:00
Chris Mason
6db4a7335d Merge branch 'fix/waitqueue-barriers' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux into for-linus-4.4 2015-10-12 16:24:40 -07:00
Chris Mason
62fb50ab7c Merge branch 'anand/sysfs-updates-v4.3-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux into for-linus-4.4
Signed-off-by: Chris Mason <clm@fb.com>
2015-10-12 16:24:15 -07:00
David Sterba
ee86395458 btrfs: comment the rest of implicit barriers before waitqueue_active
There are atomic operations that imply the barrier for waitqueue_active
mixed in an if-condition.

Signed-off-by: David Sterba <dsterba@suse.com>
2015-10-10 18:42:00 +02:00
David Sterba
f14d104dbd btrfs: switch more printks to our helpers
Convert the simple cases, not all functions provide a way to reach the
fs_info. Also skipped debugging messages (print-tree, integrity
checker and pr_debug) and messages that are printed from possibly
unfinished mount.

Signed-off-by: David Sterba <dsterba@suse.com>
2015-10-08 13:08:03 +02:00
David Sterba
b14af3b46f btrfs: switch message printers to ratelimited _in_rcu variants
Signed-off-by: David Sterba <dsterba@suse.com>
2015-10-08 11:07:55 +02:00
David Sterba
ecaeb14b91 btrfs: switch message printers to _in_rcu variants
Signed-off-by: David Sterba <dsterba@suse.com>
2015-10-08 11:07:55 +02:00
Anand Jain
f190aa471a Btrfs: add helper for closing one device
Signed-off-by: Anand Jain <anand.jain@oracle.com>
[reworded subject and changelog]
Signed-off-by: David Sterba <dsterba@suse.com>
2015-10-01 18:00:05 +02:00
Anand Jain
097efc966a Btrfs: don't log error from btrfs_get_bdev_and_sb
Originally the message was not in a helper but ended up there. We should
print error messages from callers instead.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
[reworded subject and changelog]
Signed-off-by: David Sterba <dsterba@suse.com>
2015-10-01 17:56:47 +02:00
Anand Jain
12b1c2637b Btrfs: enhance btrfs_scratch_superblock to scratch all superblocks
This patch updates and renames btrfs_scratch_superblocks, (which is used
by the replace device thread), with those fixes from the scratch
superblock code section of btrfs_rm_device(). The fixes are:
  Scratch all copies of superblock
  Notify kobject that superblock has been changed
  Update time on the device

So that btrfs_rm_device() can use the function
btrfs_scratch_superblocks() instead of its own scratch code. And further
replace deivce code which similarly releases device back to the system,
will have the fixes from the btrfs device delete.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
[renamed to btrfs_scratch_superblock]
Signed-off-by: David Sterba <dsterba@suse.com>
2015-10-01 17:37:34 +02:00
Anand Jain
d74a625987 Btrfs: use BTRFS_ERROR_DEV_MISSING_NOT_FOUND when missing device is not found
Use btrfs specific error code BTRFS_ERROR_DEV_MISSING_NOT_FOUND instead
of -ENOENT.  Next this removes the logging when user specifies "missing"
and we don't find it in the kernel device list. Logging are for system
events not for user input errors.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2015-10-01 16:47:16 +02:00
Anand Jain
a4553fefb5 Btrfs: consolidate btrfs_error() to btrfs_std_error()
btrfs_error() and btrfs_std_error() does the same thing
and calls _btrfs_std_error(), so consolidate them together.
And the main motivation is that btrfs_error() is closely
named with btrfs_err(), one handles error action the other
is to log the error, so don't closely name them.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Suggested-by: David Sterba <dsterba@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2015-09-29 16:30:00 +02:00
Anand Jain
92fc03fbdc Btrfs: SB read failure should return EIO for __bread failure
This will return EIO when __bread() fails to read SB,
instead of EINVAL.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2015-09-29 16:29:59 +02:00
Anand Jain
c1b7e47459 Btrfs: rename super_kobj to fsid_kobj
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2015-09-29 16:29:59 +02:00
Anand Jain
3257604048 Btrfs: rename btrfs_kobj_rm_device to btrfs_sysfs_rm_device_link
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2015-09-29 16:29:59 +02:00
Anand Jain
e3bd6973bc Btrfs: rename btrfs_kobj_add_device to btrfs_sysfs_add_device_link
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2015-09-29 16:29:59 +02:00
Linus Torvalds
e91eb6204f Merge branch 'for-linus-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs
Pull btrfs cleanups and fixes from Chris Mason:
 "These are small cleanups, and also some fixes for our async worker
  thread initialization.

  I was having some trouble testing these, but it ended up being a
  combination of changing around my test servers and a shiny new
  schedule while atomic from the new start/finish_plug in
  writeback_sb_inodes().

  That one only hits on btrfs raid5/6 or MD raid10, and if I wasn't
  changing a bunch of things in my test setup at once it would have been
  really clear.  Fix for writeback_sb_inodes() on the way as well"

* 'for-linus-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  Btrfs: cleanup: remove unnecessary check before btrfs_free_path is called
  btrfs: async_thread: Fix workqueue 'max_active' value when initializing
  btrfs: Add raid56 support for updating  num_tolerated_disk_barrier_failures in btrfs_balance
  btrfs: Cleanup for btrfs_calc_num_tolerated_disk_barrier_failures
  btrfs: Remove noused chunk_tree and chunk_objectid from scrub_enumerate_chunks and scrub_chunk
  btrfs: Update out-of-date "skip parity stripe" comment
2015-09-11 12:38:25 -07:00
Linus Torvalds
22365979ab Merge branch 'for-linus-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs
Pull btrfs updates from Chris Mason:
 "This has Jeff Mahoney's long standing trim patch that fixes corners
  where trims were missing.  Omar has some raid5/6 fixes, especially for
  using scrub and device replace when devices are missing.

  Zhao Lie continues cleaning and fixing things, this series fixes some
  really hard to hit corners in xfstests.  I had to pull it last merge
  window due to some deadlocks, but those are now resolved.

  I added support for Tejun's new blkio controllers.  It seems to work
  well for single devices, we'll expand to multi-device as well"

* 'for-linus-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: (47 commits)
  btrfs: fix compile when block cgroups are not enabled
  Btrfs: fix file read corruption after extent cloning and fsync
  Btrfs: check if previous transaction aborted to avoid fs corruption
  btrfs: use __GFP_NOFAIL in alloc_btrfs_bio
  btrfs: Prevent from early transaction abort
  btrfs: Remove unused arguments in tree-log.c
  btrfs: Remove useless condition in start_log_trans()
  Btrfs: add support for blkio controllers
  Btrfs: remove unused mutex from struct 'btrfs_fs_info'
  Btrfs: fix parity scrub of RAID 5/6 with missing device
  Btrfs: fix device replace of a missing RAID 5/6 device
  Btrfs: add RAID 5/6 BTRFS_RBIO_REBUILD_MISSING operation
  Btrfs: count devices correctly in readahead during RAID 5/6 replace
  Btrfs: remove misleading handling of missing device scrub
  btrfs: fix clone / extent-same deadlocks
  Btrfs: fix defrag to merge tail file extent
  Btrfs: fix warning in backref walking
  btrfs: Add WARN_ON() for double lock in btrfs_tree_lock()
  btrfs: Remove root argument in extent_data_ref_count()
  btrfs: Fix wrong comment of btrfs_alloc_tree_block()
  ...
2015-09-05 15:14:43 -07:00
Zhao Lei
943c6e9925 btrfs: Add raid56 support for updating
num_tolerated_disk_barrier_failures in btrfs_balance

Code for updating fs_info->num_tolerated_disk_barrier_failures in
btrfs_balance() lacks raid56 support.

Reason:
 Above code was wroten in 2012-08-01, together with
 btrfs_calc_num_tolerated_disk_barrier_failures()'s first version.

 Then, btrfs_calc_num_tolerated_disk_barrier_failures() got updated
 later to support raid56, but code in btrfs_balance() was not
 updated together.

Fix:
 Merge above similar code to a common function:
 btrfs_get_num_tolerated_disk_barrier_failures()
 and make it support both case.

 It can fix this bug with a bonus of cleanup, and make these code
 never in above no-sync state from now on.

Suggested-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-08-31 11:45:48 -07:00
Chris Mason
3a9508b022 btrfs: fix compile when block cgroups are not enabled
bio->bi_css and bio->bi_ioc don't exist when block cgroups are not on.
This adds an ifdef around them.  It's not perfect, but our
use of bi_ioc is being removed in the 4.3 merge window.

The bi_css usage really should go into bio_clone, but I want to make
sure that doesn't introduce problems for other bio_clone use cases.

Signed-off-by: Chris Mason <clm@fb.com>
2015-08-21 10:08:13 -07:00
Michal Hocko
277fb5fc17 btrfs: use __GFP_NOFAIL in alloc_btrfs_bio
alloc_btrfs_bio relies on GFP_NOFS allocation when committing the
transaction but this allocation context is rather weak wrt. reclaim
capabilities. The page allocator currently tries hard to not fail these
allocations if they are small (<=PAGE_ALLOC_COSTLY_ORDER) but it can
still fail if the _current_ process is the OOM killer victim. Moreover
there is an attempt to move away from the default no-fail behavior and
allow these allocation to fail more eagerly. This would lead to:

[   37.928625] kernel BUG at fs/btrfs/extent_io.c:4045

which is clearly undesirable and the nofail behavior should be explicit
if the allocation failure cannot be tolerated.

Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-08-19 14:25:15 -07:00
Kent Overstreet
0e28997ec4 btrfs: remove bio splitting and merge_bvec_fn() calls
Btrfs has been doing bio splitting from btrfs_map_bio(), by checking
device limits as well as calling ->merge_bvec_fn() etc. That is not
necessary any more, because generic_make_request() is now able to
handle arbitrarily sized bios. So clean up unnecessary code paths.

Cc: Chris Mason <clm@fb.com>
Cc: Josef Bacik <jbacik@fb.com>
Cc: linux-btrfs@vger.kernel.org
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Chris Mason <clm@fb.com>
[dpark: add more description in commit message]
Signed-off-by: Dongsu Park <dpark@posteo.net>
Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-08-13 12:31:43 -06:00
Chris Mason
46cd28555f Merge branch 'jeffm-discard-4.3' into for-linus-4.3 2015-08-09 07:35:33 -07:00
Chris Mason
da2f0f74cf Btrfs: add support for blkio controllers
This attaches accounting information to bios as we submit them so the
new blkio controllers can throttle on btrfs filesystems.

Not much is required, we're just associating bios with blkcgs during clone,
calling wbc_init_bio()/wbc_account_io() during writepages submission,
and attaching the bios to the current context during direct IO.

Finally if we are splitting bios during btrfs_map_bio, this attaches
accounting information to the split.

The end result is able to throttle nicely on single disk filesystems.  A
little more work is required for multi-device filesystems.

Signed-off-by: Chris Mason <clm@fb.com>
2015-08-09 07:35:06 -07:00
Zhaolei
dc2ee4e244 btrfs: Cleanup: Remove chunk_objectid argument from btrfs_relocate_chunk()
Remove chunk_objectid argument from btrfs_relocate_chunk() because
it is not necessary, it can also cleanup some code in caller for
prepare its value.

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-08-09 07:07:13 -07:00
Zhaolei
55e3a601c8 btrfs: Fix data checksum error cause by replace with io-load.
xfstests btrfs/070 sometimes failed.
In my test machine, its fail rate is about 30%.
In another vm(vmware), its fail rate is about 50%.

Reason:
  btrfs/070 do replace and defrag with fsstress simultaneously,
  after above operation, checksum error is found by scrub.

  Actually, it have no relationship with defrag operation, only
  replace with fsstress can trigger this bug.

  New data writen to target device have possibility rewrited by
  old data from source device by replace code in debug, to avoid
  above problem, we can set target block group to readonly in
  replace period, so new data requested by other operation will
  not write to same place with replace code.

  Before patch(4.1-rc3):
    30% failed in 100 xfstests.
  After patch:
    0% failed in 300 xfstests.

It also happened in btrfs/071 as it's another scrub with IO load tests.

Reported-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-08-09 07:07:13 -07:00
Jeff Mahoney
499f377f49 btrfs: iterate over unused chunk space in FITRIM
Since we now clean up block groups automatically as they become
empty, iterating over block groups is no longer sufficient to discard
unused space.

This patch iterates over the unused chunk space and discards any regions
that are unallocated, regardless of whether they were ever used.  This is
a change for btrfs but is consistent with other file systems.

We do this in a transactionless manner since the discard process can take
a substantial amount of time and a transaction would need to be started
before the acquisition of the device list lock.  That would mean a
transaction would be held open across /all/ of the discards collectively.
In order to prevent other threads from allocating or freeing chunks, we
hold the chunks lock across the search and discard calls.  We release it
between searches to allow the file system to perform more-or-less
normally.  Since the running transaction can commit and disappear while
we're using the transaction pointer, we take a reference to it and
release it after the search.  This is safe since it would happen normally
at the end of the transaction commit after any locks are released anyway.
We also take the commit_root_sem to protect against a transaction starting
and committing while we're running.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Tested-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-07-29 08:15:26 -07:00
Christoph Hellwig
4246a0b63b block: add a bi_error field to struct bio
Currently we have two different ways to signal an I/O error on a BIO:

 (1) by clearing the BIO_UPTODATE flag
 (2) by returning a Linux errno value to the bi_end_io callback

The first one has the drawback of only communicating a single possible
error (-EIO), and the second one has the drawback of not beeing persistent
when bios are queued up, and are not passed along from child to parent
bio in the ever more popular chaining scenario.  Having both mechanisms
available has the additional drawback of utterly confusing driver authors
and introducing bugs where various I/O submitters only deal with one of
them, and the others have to add boilerplate code to deal with both kinds
of error returns.

So add a new bi_error field to store an errno value directly in struct
bio and remove the existing mechanisms to clean all this up.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: NeilBrown <neilb@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-07-29 08:55:15 -06:00
Linus Torvalds
31b7a57c9e Merge branch 'for-linus-4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs
Pull btrfs fixes from Chris Mason:
 "This is an assortment of fixes.  Most of the commits are from Filipe
  (fsync, the inode allocation cache and a few others).  Mark kicked in
  a series fixing corners in the extent sharing ioctls, and everyone
  else fixed up on assorted other problems"

* 'for-linus-4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  Btrfs: fix wrong check for btrfs_force_chunk_alloc()
  Btrfs: fix warning of bytes_may_use
  Btrfs: fix hang when failing to submit bio of directIO
  Btrfs: fix a comment in inode.c:evict_inode_truncate_pages()
  Btrfs: fix memory corruption on failure to submit bio for direct IO
  btrfs: don't update mtime/ctime on deduped inodes
  btrfs: allow dedupe of same inode
  btrfs: fix deadlock with extent-same and readpage
  btrfs: pass unaligned length to btrfs_cmp_data()
  Btrfs: fix fsync after truncate when no_holes feature is enabled
  Btrfs: fix fsync xattr loss in the fast fsync path
  Btrfs: fix fsync data loss after append write
  Btrfs: fix crash on close_ctree() if cleaner starts new transaction
  Btrfs: fix race between caching kthread and returning inode to inode cache
  Btrfs: use kmem_cache_free when freeing entry in inode cache
  Btrfs: fix race between balance and unused block group deletion
  btrfs: add error handling for scrub_workers_get()
  btrfs: cleanup noused initialization of dev in btrfs_end_bio()
  btrfs: qgroup: allow user to clear the limitation on qgroup
2015-07-11 10:26:34 -07:00
Linus Torvalds
043cd04950 Merge branch 'for-linus-4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs
Pull btrfs updates from Chris Mason:
 "Outside of our usual batch of fixes, this integrates the subvolume
  quota updates that Qu Wenruo from Fujitsu has been working on for a
  few releases now.  He gets an extra gold star for making btrfs smaller
  this time, and fixing a number of quota corners in the process.

  Dave Sterba tested and integrated Anand Jain's sysfs improvements.
  Outside of exporting a symbol (ack'd by Greg) these are all internal
  to btrfs and it's mostly cleanups and fixes.  Anand also attached some
  of our sysfs objects to our internal device management structs instead
  of an object off the super block.  It will make device management
  easier overall and it's a better fit for how the sysfs files are used.
  None of the existing sysfs files are moved around.

  Thanks for all the fixes everyone"

* 'for-linus-4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: (87 commits)
  btrfs: delayed-ref: double free in btrfs_add_delayed_tree_ref()
  Btrfs: Check if kobject is initialized before put
  lib: export symbol kobject_move()
  Btrfs: sysfs: add support to show replacing target in the sysfs
  Btrfs: free the stale device
  Btrfs: use received_uuid of parent during send
  Btrfs: fix use-after-free in btrfs_replay_log
  btrfs: wait for delayed iputs on no space
  btrfs: qgroup: Make snapshot accounting work with new extent-oriented qgroup.
  btrfs: qgroup: Add the ability to skip given qgroup for old/new_roots.
  btrfs: ulist: Add ulist_del() function.
  btrfs: qgroup: Cleanup the old ref_node-oriented mechanism.
  btrfs: qgroup: Switch self test to extent-oriented qgroup mechanism.
  btrfs: qgroup: Switch to new extent-oriented qgroup mechanism.
  btrfs: qgroup: Switch rescan to new mechanism.
  btrfs: qgroup: Add new qgroup calculation function btrfs_qgroup_account_extents().
  btrfs: backref: Add special time_seq == (u64)-1 case for btrfs_find_all_roots().
  btrfs: qgroup: Add new function to record old_roots.
  btrfs: qgroup: Record possible quota-related extent for qgroup.
  btrfs: qgroup: Add function qgroup_update_counters().
  ...
2015-06-30 20:07:45 -07:00
Filipe Manana
67c5e7d464 Btrfs: fix race between balance and unused block group deletion
We have a race between deleting an unused block group and balancing the
same block group that leads to an assertion failure/BUG(), producing the
following trace:

[181631.208236] BTRFS: assertion failed: 0, file: fs/btrfs/volumes.c, line: 2622
[181631.220591] ------------[ cut here ]------------
[181631.222959] kernel BUG at fs/btrfs/ctree.h:4062!
[181631.223932] invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
[181631.224566] Modules linked in: btrfs dm_flakey dm_mod crc32c_generic xor raid6_pq nfsd auth_rpcgss oid_registry nfs_acl nfs lockd grace fscache sunrpc loop fuse acpi_cpufreq parpor$
[181631.224566] CPU: 8 PID: 17451 Comm: btrfs Tainted: G        W       4.1.0-rc5-btrfs-next-10+ #1
[181631.224566] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.8.1-0-g4adadbd-20150316_085822-nilsson.home.kraxel.org 04/01/2014
[181631.224566] task: ffff880127e09590 ti: ffff8800b5824000 task.ti: ffff8800b5824000
[181631.224566] RIP: 0010:[<ffffffffa03f19f6>]  [<ffffffffa03f19f6>] assfail.constprop.50+0x1e/0x20 [btrfs]
[181631.224566] RSP: 0018:ffff8800b5827ae8  EFLAGS: 00010246
[181631.224566] RAX: 0000000000000040 RBX: ffff8800109fc218 RCX: ffffffff81095dce
[181631.224566] RDX: 0000000000005124 RSI: ffffffff81464819 RDI: 00000000ffffffff
[181631.224566] RBP: ffff8800b5827ae8 R08: 0000000000000001 R09: 0000000000000000
[181631.224566] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8800109fc200
[181631.224566] R13: ffff880020095000 R14: ffff8800b1a13f38 R15: ffff880020095000
[181631.224566] FS:  00007f70ca0b0c80(0000) GS:ffff88013ec00000(0000) knlGS:0000000000000000
[181631.224566] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[181631.224566] CR2: 00007f2872ab6e68 CR3: 00000000a717c000 CR4: 00000000000006e0
[181631.224566] Stack:
[181631.224566]  ffff8800b5827ba8 ffffffffa03f3916 ffff8800b5827b38 ffffffffa03d080e
[181631.224566]  ffffffffa03d1423 ffff880020095000 ffff88001233c000 0000000000000001
[181631.224566]  ffff880020095000 ffff8800b1a13f38 0000000a69c00000 0000000000000000
[181631.224566] Call Trace:
[181631.224566]  [<ffffffffa03f3916>] btrfs_remove_chunk+0xa4/0x6bb [btrfs]
[181631.224566]  [<ffffffffa03d080e>] ? join_transaction.isra.8+0xb9/0x3ba [btrfs]
[181631.224566]  [<ffffffffa03d1423>] ? wait_current_trans.isra.13+0x22/0xfc [btrfs]
[181631.224566]  [<ffffffffa03f3fbc>] btrfs_relocate_chunk.isra.29+0x8f/0xa7 [btrfs]
[181631.224566]  [<ffffffffa03f54df>] btrfs_balance+0xaa4/0xc52 [btrfs]
[181631.224566]  [<ffffffffa03fd388>] btrfs_ioctl_balance+0x23f/0x2b0 [btrfs]
[181631.224566]  [<ffffffff810872f9>] ? trace_hardirqs_on+0xd/0xf
[181631.224566]  [<ffffffffa04019a3>] btrfs_ioctl+0xfe2/0x2220 [btrfs]
[181631.224566]  [<ffffffff812603ed>] ? __this_cpu_preempt_check+0x13/0x15
[181631.224566]  [<ffffffff81084669>] ? arch_local_irq_save+0x9/0xc
[181631.224566]  [<ffffffff81138def>] ? handle_mm_fault+0x834/0xcd2
[181631.224566]  [<ffffffff81138def>] ? handle_mm_fault+0x834/0xcd2
[181631.224566]  [<ffffffff8103e48c>] ? __do_page_fault+0x211/0x424
[181631.224566]  [<ffffffff811755e6>] do_vfs_ioctl+0x3c6/0x479
(...)

The sequence of steps leading to this are:

           CPU 0                                         CPU 1

  btrfs_balance()
    btrfs_relocate_chunk()

      btrfs_relocate_block_group(bg X)
        btrfs_lookup_block_group(bg X)

                                               cleaner_kthread
                                                  locks fs_info->cleaner_mutex

                                                  btrfs_delete_unused_bgs()
                                                    finds bg X, which became
                                                    unused in the previous
                                                    transaction

                                                    checks bg X ->ro == 0,
                                                    so it proceeds
        sets bg X ->ro to 1
        (btrfs_set_block_group_ro(bg X))

        blocks on fs_info->cleaner_mutex
                                                    btrfs_remove_chunk(bg X)
                                                  unlocks fs_info->cleaner_mutex

        acquires fs_info->cleaner_mutex
        relocate_block_group()
          --> does nothing, no extents found in
              the extent tree from bg X
        unlocks fs_info->cleaner_mutex

      btrfs_relocate_block_group(bg X) returns

    btrfs_remove_chunk(bg X)
       extent map not found
          --> ASSERT(0)

Fix this by using a new mutex to make sure these 2 operations, block
group relocation and removal, are serialized.

This issue is reproducible by running fstests generic/038 (which stresses
chunk allocation and automatic removal of unused block groups) together
with the following balance loop:

    while true; do btrfs balance start -dusage=0 <mountpoint> ; done

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-06-30 14:36:46 -07:00
Zhao Lei
65f5333875 btrfs: cleanup noused initialization of dev in btrfs_end_bio()
It is introduced by:
 c404e0dc2c
 Btrfs: fix use-after-free in the finishing procedure of the device replace

But seems no relationship with that bug, this patch revirt these
code block for cleanup.

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-06-30 13:20:02 -07:00
Linus Torvalds
bfffa1cc9d Merge branch 'for-4.2/core' of git://git.kernel.dk/linux-block
Pull core block IO update from Jens Axboe:
 "Nothing really major in here, mostly a collection of smaller
  optimizations and cleanups, mixed with various fixes.  In more detail,
  this contains:

   - Addition of policy specific data to blkcg for block cgroups.  From
     Arianna Avanzini.

   - Various cleanups around command types from Christoph.

   - Cleanup of the suspend block I/O path from Christoph.

   - Plugging updates from Shaohua and Jeff Moyer, for blk-mq.

   - Eliminating atomic inc/dec of both remaining IO count and reference
     count in a bio.  From me.

   - Fixes for SG gap and chunk size support for data-less (discards)
     IO, so we can merge these better.  From me.

   - Small restructuring of blk-mq shared tag support, freeing drivers
     from iterating hardware queues.  From Keith Busch.

   - A few cfq-iosched tweaks, from Tahsin Erdogan and me.  Makes the
     IOPS mode the default for non-rotational storage"

* 'for-4.2/core' of git://git.kernel.dk/linux-block: (35 commits)
  cfq-iosched: fix other locations where blkcg_to_cfqgd() can return NULL
  cfq-iosched: fix sysfs oops when attempting to read unconfigured weights
  cfq-iosched: move group scheduling functions under ifdef
  cfq-iosched: fix the setting of IOPS mode on SSDs
  blktrace: Add blktrace.c to BLOCK LAYER in MAINTAINERS file
  block, cgroup: implement policy-specific per-blkcg data
  block: Make CFQ default to IOPS mode on SSDs
  block: add blk_set_queue_dying() to blkdev.h
  blk-mq: Shared tag enhancements
  block: don't honor chunk sizes for data-less IO
  block: only honor SG gap prevention for merges that contain data
  block: fix returnvar.cocci warnings
  block, dm: don't copy bios for request clones
  block: remove management of bi_remaining when restoring original bi_end_io
  block: replace trylock with mutex_lock in blkdev_reread_part()
  block: export blkdev_reread_part() and __blkdev_reread_part()
  suspend: simplify block I/O handling
  block: collapse bio bit space
  block: remove unused BIO_RW_BLOCK and BIO_EOF flags
  block: remove BIO_EOPNOTSUPP
  ...
2015-06-25 14:29:53 -07:00
Chris Mason
c40b7b064f Merge branch 'sysfs-fsdevices-4.2-part1' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux into anand 2015-06-23 05:34:39 -07:00
Anand Jain
d2ff1b2008 Btrfs: sysfs: add support to show replacing target in the sysfs
This patch will add support to show the replacing target in sysfs
during the process of replacement.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
2015-06-19 14:03:54 +02:00
Anand Jain
4fde46f0cc Btrfs: free the stale device
When btrfs on a device is overwritten with a new btrfs (mkfs),
the old btrfs instance in the kernel becomes stale. So with this
patch, if kernel finds device is overwritten then delete the stale
fsid/uuid.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
2015-06-19 14:03:13 +02:00
Filipe Manana
4617ea3a52 Btrfs: fix necessary chunk tree space calculation when allocating a chunk
When allocating a new chunk or removing one we need to update num_devs
device items and insert or remove a chunk item in the chunk tree, so
in the worst case the space needed in the chunk space_info is:

  btrfs_calc_trunc_metadata_size(chunk_root, num_devs) +
     btrfs_calc_trans_metadata_size(chunk_root, 1)

That is, in the worst case we need to cow num_devs paths and cow 1 other
path that can result in splitting every node and leaf, and each path
consisting of BTRFS_MAX_LEVEL - 1 nodes and 1 leaf. We were requiring
some additional chunk_root->nodesize * BTRFS_MAX_LEVEL * num_devs bytes,
which were unnecessary since updating the existing device items does
not result in splitting the nodes and leaf since after updating them
they remain with the same size.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-06-10 07:02:46 -07:00
Filipe Manana
39c2d7facc Btrfs: fix -ENOSPC on block group removal
Unlike when attempting to allocate a new block group, where we check
that we have enough space in the system space_info to update the device
items and insert a new chunk item in the chunk tree, we were not checking
if the system space_info had enough space for updating the device items
and deleting the chunk item in the chunk tree. This often lead to -ENOSPC
error when attempting to allocate blocks for the chunk tree (during btree
node/leaf COW operations) while updating the device items or deleting the
chunk item, which resulted in the current transaction being aborted and
turning the filesystem into read-only mode.

While running fstests generic/038, which stresses allocation of block
groups and removal of unused block groups, with a large scratch device
(750Gb) this happened often, despite more than enough unallocated space,
and resulted in the following trace:

[68663.586604] WARNING: CPU: 3 PID: 1521 at fs/btrfs/super.c:260 __btrfs_abort_transaction+0x52/0x114 [btrfs]()
[68663.600407] BTRFS: Transaction aborted (error -28)
(...)
[68663.730829] Call Trace:
[68663.732585]  [<ffffffff8142fa46>] dump_stack+0x4f/0x7b
[68663.734334]  [<ffffffff8108b6a2>] ? console_unlock+0x361/0x3ad
[68663.739980]  [<ffffffff81045ea5>] warn_slowpath_common+0xa1/0xbb
[68663.757153]  [<ffffffffa036ca6d>] ? __btrfs_abort_transaction+0x52/0x114 [btrfs]
[68663.760925]  [<ffffffff81045f05>] warn_slowpath_fmt+0x46/0x48
[68663.762854]  [<ffffffffa03b159d>] ? btrfs_update_device+0x15a/0x16c [btrfs]
[68663.764073]  [<ffffffffa036ca6d>] __btrfs_abort_transaction+0x52/0x114 [btrfs]
[68663.765130]  [<ffffffffa03b3638>] btrfs_remove_chunk+0x597/0x5ee [btrfs]
[68663.765998]  [<ffffffffa0384663>] ? btrfs_delete_unused_bgs+0x245/0x296 [btrfs]
[68663.767068]  [<ffffffffa0384676>] btrfs_delete_unused_bgs+0x258/0x296 [btrfs]
[68663.768227]  [<ffffffff8143527f>] ? _raw_spin_unlock_irq+0x2d/0x4c
[68663.769081]  [<ffffffffa038b109>] cleaner_kthread+0x13d/0x16c [btrfs]
[68663.799485]  [<ffffffffa038afcc>] ? btrfs_alloc_root+0x28/0x28 [btrfs]
[68663.809208]  [<ffffffff8105f367>] kthread+0xef/0xf7
[68663.828795]  [<ffffffff810e603f>] ? time_hardirqs_on+0x15/0x28
[68663.844942]  [<ffffffff8105f278>] ? __kthread_parkme+0xad/0xad
[68663.846486]  [<ffffffff81435a88>] ret_from_fork+0x58/0x90
[68663.847760]  [<ffffffff8105f278>] ? __kthread_parkme+0xad/0xad
[68663.849503] ---[ end trace 798477c6d6dbaad6 ]---
[68663.850525] BTRFS: error (device sdc) in btrfs_remove_chunk:2652: errno=-28 No space left

So fix this by verifying that enough space exists in system space_info,
and reserving the space in the chunk block reserve, before attempting to
delete the block group and allocate a new system chunk if we don't have
enough space to perform the necessary updates and delete in the chunk
tree. Like for the block group creation case, we don't error our if we
fail to allocate a new system chunk, since we might end up not needing
it (no node/leaf splits happen during the COW operations and/or we end
up not needing to COW any btree nodes or leafs because they were already
COWed in the current transaction and their writeback didn't start yet).

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-06-03 04:03:05 -07:00
Filipe Manana
c152b63efc Btrfs: fix chunk allocation regression leading to transaction abort
With commit 1b98450816 ("Btrfs: fix find_free_dev_extent() malfunction
in case device tree has hole") introduced in the kernel 4.1 merge window,
we end up using part of a device hole for which there are already pending
chunks or pinned chunks. Before that commit we didn't use the hole and
would just move on to the next hole in the device.

However when we adjust the start offset for the chunk allocation and we
have pinned chunks, we set it blindly to the end offset of the pinned
chunk we are currently processing, which is dangerous because we can
have a pending chunk that has a start offset that matches the end offset
of our pinned chunk - leading us to a case where we end up getting two
pending chunks that start at the same physical device offset, which makes
us later abort the current transaction with -EEXIST when finishing the
chunk allocation at btrfs_create_pending_block_groups():

[194737.659017] ------------[ cut here ]------------
[194737.660192] WARNING: CPU: 15 PID: 31111 at fs/btrfs/super.c:260 __btrfs_abort_transaction+0x52/0x106 [btrfs]()
[194737.662209] BTRFS: Transaction aborted (error -17)
[194737.663175] Modules linked in: btrfs dm_snapshot dm_bufio dm_flakey dm_mod crc32c_generic xor raid6_pq nfsd auth_rpcgss oid_registry nfs_acl nfs lockd grace fscache sunrpc loop fuse
[194737.674015] CPU: 15 PID: 31111 Comm: xfs_io Tainted: G        W       4.0.0-rc5-btrfs-next-9+ #2
[194737.675986] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014
[194737.682999]  0000000000000009 ffff8800564c7a98 ffffffff8142fa46 ffffffff8108b6a2
[194737.684540]  ffff8800564c7ae8 ffff8800564c7ad8 ffffffff81045ea5 ffff8800564c7b78
[194737.686017]  ffffffffa0383aa7 00000000ffffffef ffff88000c7ba000 ffff8801a1f66f40
[194737.687509] Call Trace:
[194737.688068]  [<ffffffff8142fa46>] dump_stack+0x4f/0x7b
[194737.689027]  [<ffffffff8108b6a2>] ? console_unlock+0x361/0x3ad
[194737.690095]  [<ffffffff81045ea5>] warn_slowpath_common+0xa1/0xbb
[194737.691198]  [<ffffffffa0383aa7>] ? __btrfs_abort_transaction+0x52/0x106 [btrfs]
[194737.693789]  [<ffffffff81045f05>] warn_slowpath_fmt+0x46/0x48
[194737.695065]  [<ffffffffa0383aa7>] __btrfs_abort_transaction+0x52/0x106 [btrfs]
[194737.696806]  [<ffffffffa039a3bd>] btrfs_create_pending_block_groups+0x101/0x130 [btrfs]
[194737.698683]  [<ffffffffa03aa433>] __btrfs_end_transaction+0x84/0x366 [btrfs]
[194737.700329]  [<ffffffffa03aa725>] btrfs_end_transaction+0x10/0x12 [btrfs]
[194737.701924]  [<ffffffffa0394b51>] btrfs_check_data_free_space+0x11f/0x27c [btrfs]
[194737.703675]  [<ffffffffa03b8ba4>] __btrfs_buffered_write+0x16a/0x4c8 [btrfs]
[194737.705417]  [<ffffffffa03bb502>] ? btrfs_file_write_iter+0x19a/0x431 [btrfs]
[194737.707058]  [<ffffffffa03bb511>] ? btrfs_file_write_iter+0x1a9/0x431 [btrfs]
[194737.708560]  [<ffffffffa03bb68d>] btrfs_file_write_iter+0x325/0x431 [btrfs]
[194737.710673]  [<ffffffff81067d85>] ? get_parent_ip+0xe/0x3e
[194737.712076]  [<ffffffff811534c3>] new_sync_write+0x7c/0xa0
[194737.713293]  [<ffffffff81153b58>] vfs_write+0xb2/0x117
[194737.714443]  [<ffffffff81154424>] SyS_pwrite64+0x64/0x82
[194737.715646]  [<ffffffff81435b32>] system_call_fastpath+0x12/0x17
[194737.717175] ---[ end trace f2d5dc04e56d7e48 ]---
[194737.718170] BTRFS: error (device sdc) in btrfs_create_pending_block_groups:9524: errno=-17 Object already exists

The -EEXIST failure comes from btrfs_finish_chunk_alloc(), called by
btrfs_create_pending_block_groups(), when it attempts to insert a
duplicated device extent item via btrfs_alloc_dev_extent().

This issue was reproducible with fstests generic/038 running in a loop for
several hours (it's very hard to hit) and using MOUNT_OPTIONS="-o discard".
Applying Jeff's recent patch titled "btrfs: add missing discards when
unpinning extents with -o discard" makes the issue much easier to reproduce
(usually within 4 to 5 hours), since it pins chunks for longer periods of
time when an unused block group is deleted by the cleaner kthread.

Fix this by making sure that we never adjust the start offset to a lower
value than it currently has.

Fixes: 1b98450816 ("Btrfs: fix find_free_dev_extent() malfunction in case device tree has hole"
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-06-03 04:02:55 -07:00