Commit Graph

985 Commits

Author SHA1 Message Date
Mike Christie 81a75f6781 btrfs: use bio fields for op and flags
The bio REQ_OP and bi_rw rq_flag_bits are now always setup, so there is
no need to pass around the rq_flag_bits bits too. btrfs users should
should access the bio insead.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-06-07 13:41:38 -06:00
David Sterba 42f31734eb Merge branch 'cleanups-4.7' into for-chris-4.7-20160525 2016-05-25 22:51:03 +02:00
Nicholas D Steeves 0132761017 btrfs: fix string and comment grammatical issues and typos
Signed-off-by: Nicholas D Steeves <nsteeves@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2016-05-25 22:35:14 +02:00
Chris Mason c315ef8d9d Merge branch 'for-chris-4.7' of git://git.kernel.org/pub/scm/linux/kernel/git/fdmanana/linux into for-linus-4.7
Signed-off-by: Chris Mason <clm@fb.com>
2016-05-17 14:43:19 -07:00
David Sterba 680834ca0a Merge branch 'foreign/jeffm/uapi' into for-chris-4.7-20160516
# Conflicts:
#	include/uapi/linux/btrfs.h
2016-05-16 15:46:29 +02:00
David Sterba 5ef64a3e75 Merge branch 'cleanups-4.7' into for-chris-4.7-20160516 2016-05-16 15:46:24 +02:00
Filipe Manana f78c436c39 Btrfs: fix race between block group relocation and nocow writes
Relocation of a block group waits for all existing tasks flushing
dellaloc, starting direct IO writes and any ordered extents before
starting the relocation process. However for direct IO writes that end
up doing nocow (inode either has the flag nodatacow set or the write is
against a prealloc extent) we have a short time window that allows for a
race that makes relocation proceed without waiting for the direct IO
write to complete first, resulting in data loss after the relocation
finishes. This is illustrated by the following diagram:

           CPU 1                                     CPU 2

 btrfs_relocate_block_group(bg X)

                                               direct IO write starts against
                                               an extent in block group X
                                               using nocow mode (inode has the
                                               nodatacow flag or the write is
                                               for a prealloc extent)

                                               btrfs_direct_IO()
                                                 btrfs_get_blocks_direct()
                                                   --> can_nocow_extent() returns 1

   btrfs_inc_block_group_ro(bg X)
     --> turns block group into RO mode

   btrfs_wait_ordered_roots()
     --> returns and does not know about
         the DIO write happening at CPU 2
         (the task there has not created
          yet an ordered extent)

   relocate_block_group(bg X)
     --> rc->stage == MOVE_DATA_EXTENTS

     find_next_extent()
       --> returns extent that the DIO
           write is going to write to

     relocate_data_extent()

       relocate_file_extent_cluster()

         --> reads the extent from disk into
             pages belonging to the relocation
             inode and dirties them

                                                   --> creates DIO ordered extent

                                                 btrfs_submit_direct()
                                                   --> submits bio against a location
                                                       on disk obtained from an extent
                                                       map before the relocation started

   btrfs_wait_ordered_range()
     --> writes all the pages read before
         to disk (belonging to the
         relocation inode)

   relocation finishes

                                                 bio completes and wrote new data
                                                 to the old location of the block
                                                 group

So fix this by tracking the number of nocow writers for a block group and
make sure relocation waits for that number to go down to 0 before starting
to move the extents.

The same race can also happen with buffered writes in nocow mode since the
patch I recently made titled "Btrfs: don't do unnecessary delalloc flushes
when relocating", because we are no longer flushing all delalloc which
served as a synchonization mechanism (due to page locking) and ensured
the ordered extents for nocow buffered writes were created before we
called btrfs_wait_ordered_roots(). The race with direct IO writes in nocow
mode existed before that patch (no pages are locked or used during direct
IO) and that fixed only races with direct IO writes that do cow.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
2016-05-13 01:59:34 +01:00
Filipe Manana 9cfa3e34e2 Btrfs: don't do unnecessary delalloc flushes when relocating
Before we start the actual relocation process of a block group, we do
calls to flush delalloc of all inodes and then wait for ordered extents
to complete. However we do these flush calls just to make sure we don't
race with concurrent tasks that have actually already started to run
delalloc and have allocated an extent from the block group we want to
relocate, right before we set it to readonly mode, but have not yet
created the respective ordered extents. The flush calls make us wait
for such concurrent tasks because they end up calling
filemap_fdatawrite_range() (through btrfs_start_delalloc_roots() ->
__start_delalloc_inodes() -> btrfs_alloc_delalloc_work() ->
btrfs_run_delalloc_work()) which ends up serializing us with those tasks
due to attempts to lock the same pages (and the delalloc flush procedure
calls the allocator and creates the ordered extents before unlocking the
pages).

These flushing calls not only make us waste time (cpu, IO) but also reduce
the chances of writing larger extents (applications might be writing to
contiguous ranges and we flush before they finish dirtying the whole
ranges).

So make sure we don't flush delalloc and just wait for concurrent tasks
that have already started flushing delalloc and have allocated an extent
from the block group we are about to relocate.

This change also ends up fixing a race with direct IO writes that makes
relocation not wait for direct IO ordered extents. This race is
illustrated by the following diagram:

        CPU 1                                       CPU 2

 btrfs_relocate_block_group(bg X)

                                           starts direct IO write,
                                           target inode currently has no
                                           ordered extents ongoing nor
                                           dirty pages (delalloc regions),
                                           therefore the root for our inode
                                           is not in the list
                                           fs_info->ordered_roots

                                           btrfs_direct_IO()
                                             __blockdev_direct_IO()
                                               btrfs_get_blocks_direct()
                                                 btrfs_lock_extent_direct()
                                                   locks range in the io tree
                                                 btrfs_new_extent_direct()
                                                   btrfs_reserve_extent()
                                                     --> extent allocated
                                                         from bg X

   btrfs_inc_block_group_ro(bg X)

   btrfs_start_delalloc_roots()
     __start_delalloc_inodes()
       --> does nothing, no dealloc ranges
           in the inode's io tree so the
           inode's root is not in the list
           fs_info->delalloc_roots

   btrfs_wait_ordered_roots()
     --> does not find the inode's root in the
         list fs_info->ordered_roots

     --> ends up not waiting for the direct IO
         write started by the task at CPU 2

   relocate_block_group(rc->stage ==
     MOVE_DATA_EXTENTS)

     prepare_to_relocate()
       btrfs_commit_transaction()

     iterates the extent tree, using its
     commit root and moves extents into new
     locations

                                                   btrfs_add_ordered_extent_dio()
                                                     --> now a ordered extent is
                                                         created and added to the
                                                         list root->ordered_extents
                                                         and the root added to the
                                                         list fs_info->ordered_roots
                                                     --> this is too late and the
                                                         task at CPU 1 already
                                                         started the relocation

     btrfs_commit_transaction()

                                                   btrfs_finish_ordered_io()
                                                     btrfs_alloc_reserved_file_extent()
                                                       --> adds delayed data reference
                                                           for the extent allocated
                                                           from bg X

   relocate_block_group(rc->stage ==
     UPDATE_DATA_PTRS)

     prepare_to_relocate()
       btrfs_commit_transaction()
         --> delayed refs are run, so an extent
             item for the allocated extent from
             bg X is added to extent tree
         --> commit roots are switched, so the
             next scan in the extent tree will
             see the extent item

     sees the extent in the extent tree

When this happens the relocation produces the following warning when it
finishes:

[ 7260.832836] ------------[ cut here ]------------
[ 7260.834653] WARNING: CPU: 5 PID: 6765 at fs/btrfs/relocation.c:4318 btrfs_relocate_block_group+0x245/0x2a1 [btrfs]()
[ 7260.838268] Modules linked in: btrfs crc32c_generic xor ppdev raid6_pq psmouse sg acpi_cpufreq evdev i2c_piix4 tpm_tis serio_raw tpm i2c_core pcspkr parport_pc
[ 7260.850935] CPU: 5 PID: 6765 Comm: btrfs Not tainted 4.5.0-rc6-btrfs-next-28+ #1
[ 7260.852998] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS by qemu-project.org 04/01/2014
[ 7260.852998]  0000000000000000 ffff88020bf57bc0 ffffffff812648b3 0000000000000000
[ 7260.852998]  0000000000000009 ffff88020bf57bf8 ffffffff81051608 ffffffffa03c1b2d
[ 7260.852998]  ffff8800b2bbb800 0000000000000000 ffff8800b17bcc58 ffff8800399dd000
[ 7260.852998] Call Trace:
[ 7260.852998]  [<ffffffff812648b3>] dump_stack+0x67/0x90
[ 7260.852998]  [<ffffffff81051608>] warn_slowpath_common+0x99/0xb2
[ 7260.852998]  [<ffffffffa03c1b2d>] ? btrfs_relocate_block_group+0x245/0x2a1 [btrfs]
[ 7260.852998]  [<ffffffff810516d4>] warn_slowpath_null+0x1a/0x1c
[ 7260.852998]  [<ffffffffa03c1b2d>] btrfs_relocate_block_group+0x245/0x2a1 [btrfs]
[ 7260.852998]  [<ffffffffa039d9de>] btrfs_relocate_chunk.isra.29+0x66/0xdb [btrfs]
[ 7260.852998]  [<ffffffffa039f314>] btrfs_balance+0xde1/0xe4e [btrfs]
[ 7260.852998]  [<ffffffff8127d671>] ? debug_smp_processor_id+0x17/0x19
[ 7260.852998]  [<ffffffffa03a9583>] btrfs_ioctl_balance+0x255/0x2d3 [btrfs]
[ 7260.852998]  [<ffffffffa03ac96a>] btrfs_ioctl+0x11e0/0x1dff [btrfs]
[ 7260.852998]  [<ffffffff811451df>] ? handle_mm_fault+0x443/0xd63
[ 7260.852998]  [<ffffffff81491817>] ? _raw_spin_unlock+0x31/0x44
[ 7260.852998]  [<ffffffff8108b36a>] ? arch_local_irq_save+0x9/0xc
[ 7260.852998]  [<ffffffff811876ab>] vfs_ioctl+0x18/0x34
[ 7260.852998]  [<ffffffff81187cb2>] do_vfs_ioctl+0x550/0x5be
[ 7260.852998]  [<ffffffff81190c30>] ? __fget_light+0x4d/0x71
[ 7260.852998]  [<ffffffff81187d77>] SyS_ioctl+0x57/0x79
[ 7260.852998]  [<ffffffff81492017>] entry_SYSCALL_64_fastpath+0x12/0x6b
[ 7260.893268] ---[ end trace eb7803b24ebab8ad ]---

This is because at the end of the first stage, in relocate_block_group(),
we commit the current transaction, which makes delayed refs run, the
commit roots are switched and so the second stage will find the extent
item that the ordered extent added to the delayed refs. But this extent
was not moved (ordered extent completed after first stage finished), so
at the end of the relocation our block group item still has a positive
used bytes counter, triggering a warning at the end of
btrfs_relocate_block_group(). Later on when trying to read the extent
contents from disk we hit a BUG_ON() due to the inability to map a block
with a logical address that belongs to the block group we relocated and
is no longer valid, resulting in the following trace:

[ 7344.885290] BTRFS critical (device sdi): unable to find logical 12845056 len 4096
[ 7344.887518] ------------[ cut here ]------------
[ 7344.888431] kernel BUG at fs/btrfs/inode.c:1833!
[ 7344.888431] invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
[ 7344.888431] Modules linked in: btrfs crc32c_generic xor ppdev raid6_pq psmouse sg acpi_cpufreq evdev i2c_piix4 tpm_tis serio_raw tpm i2c_core pcspkr parport_pc
[ 7344.888431] CPU: 0 PID: 6831 Comm: od Tainted: G        W       4.5.0-rc6-btrfs-next-28+ #1
[ 7344.888431] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS by qemu-project.org 04/01/2014
[ 7344.888431] task: ffff880215818600 ti: ffff880204684000 task.ti: ffff880204684000
[ 7344.888431] RIP: 0010:[<ffffffffa037c88c>]  [<ffffffffa037c88c>] btrfs_merge_bio_hook+0x54/0x6b [btrfs]
[ 7344.888431] RSP: 0018:ffff8802046878f0  EFLAGS: 00010282
[ 7344.888431] RAX: 00000000ffffffea RBX: 0000000000001000 RCX: 0000000000000001
[ 7344.888431] RDX: ffff88023ec0f950 RSI: ffffffff8183b638 RDI: 00000000ffffffff
[ 7344.888431] RBP: ffff880204687908 R08: 0000000000000001 R09: 0000000000000000
[ 7344.888431] R10: ffff880204687770 R11: ffffffff82f2d52d R12: 0000000000001000
[ 7344.888431] R13: ffff88021afbfee8 R14: 0000000000006208 R15: ffff88006cd199b0
[ 7344.888431] FS:  00007f1f9e1d6700(0000) GS:ffff88023ec00000(0000) knlGS:0000000000000000
[ 7344.888431] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 7344.888431] CR2: 00007f1f9dc8cb60 CR3: 000000023e3b6000 CR4: 00000000000006f0
[ 7344.888431] Stack:
[ 7344.888431]  0000000000001000 0000000000001000 ffff880204687b98 ffff880204687950
[ 7344.888431]  ffffffffa0395c8f ffffea0004d64d48 0000000000000000 0000000000001000
[ 7344.888431]  ffffea0004d64d48 0000000000001000 0000000000000000 0000000000000000
[ 7344.888431] Call Trace:
[ 7344.888431]  [<ffffffffa0395c8f>] submit_extent_page+0xf5/0x16f [btrfs]
[ 7344.888431]  [<ffffffffa03970ac>] __do_readpage+0x4a0/0x4f1 [btrfs]
[ 7344.888431]  [<ffffffffa039680d>] ? btrfs_create_repair_bio+0xcb/0xcb [btrfs]
[ 7344.888431]  [<ffffffffa037eeb4>] ? btrfs_writepage_start_hook+0xbc/0xbc [btrfs]
[ 7344.888431]  [<ffffffff8108df55>] ? trace_hardirqs_on+0xd/0xf
[ 7344.888431]  [<ffffffffa039728c>] __do_contiguous_readpages.constprop.26+0xc2/0xe4 [btrfs]
[ 7344.888431]  [<ffffffffa037eeb4>] ? btrfs_writepage_start_hook+0xbc/0xbc [btrfs]
[ 7344.888431]  [<ffffffffa039739b>] __extent_readpages.constprop.25+0xed/0x100 [btrfs]
[ 7344.888431]  [<ffffffff81129d24>] ? lru_cache_add+0xe/0x10
[ 7344.888431]  [<ffffffffa0397ea8>] extent_readpages+0x160/0x1aa [btrfs]
[ 7344.888431]  [<ffffffffa037eeb4>] ? btrfs_writepage_start_hook+0xbc/0xbc [btrfs]
[ 7344.888431]  [<ffffffff8115daad>] ? alloc_pages_current+0xa9/0xcd
[ 7344.888431]  [<ffffffffa037cdc9>] btrfs_readpages+0x1f/0x21 [btrfs]
[ 7344.888431]  [<ffffffff81128316>] __do_page_cache_readahead+0x168/0x1fc
[ 7344.888431]  [<ffffffff811285a0>] ondemand_readahead+0x1f6/0x207
[ 7344.888431]  [<ffffffff811285a0>] ? ondemand_readahead+0x1f6/0x207
[ 7344.888431]  [<ffffffff8111cf34>] ? pagecache_get_page+0x2b/0x154
[ 7344.888431]  [<ffffffff8112870e>] page_cache_sync_readahead+0x3d/0x3f
[ 7344.888431]  [<ffffffff8111dbf7>] generic_file_read_iter+0x197/0x4e1
[ 7344.888431]  [<ffffffff8117773a>] __vfs_read+0x79/0x9d
[ 7344.888431]  [<ffffffff81178050>] vfs_read+0x8f/0xd2
[ 7344.888431]  [<ffffffff81178a38>] SyS_read+0x50/0x7e
[ 7344.888431]  [<ffffffff81492017>] entry_SYSCALL_64_fastpath+0x12/0x6b
[ 7344.888431] Code: 8d 4d e8 45 31 c9 45 31 c0 48 8b 00 48 c1 e2 09 48 8b 80 80 fc ff ff 4c 89 65 e8 48 8b b8 f0 01 00 00 e8 1d 42 02 00 85 c0 79 02 <0f> 0b 4c 0
[ 7344.888431] RIP  [<ffffffffa037c88c>] btrfs_merge_bio_hook+0x54/0x6b [btrfs]
[ 7344.888431]  RSP <ffff8802046878f0>
[ 7344.970544] ---[ end trace eb7803b24ebab8ae ]---

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
2016-05-13 01:59:16 +01:00
Jeff Mahoney db6711600e btrfs: uapi/linux/btrfs_tree.h migration, item types and defines
The BTRFS_IOC_SEARCH_TREE ioctl returns file system items directly
to userspace.  In order to decode them, full type information is required.

Create a new header, btrfs_tree to contain these since most users won't
need them.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2016-04-28 11:06:41 +02:00
Jeff Mahoney 33ca913349 btrfs: uapi/linux/btrfs.h migration, move struct btrfs_ioctl_defrag_range_args
struct btrfs_ioctl_defrag_range_args is used by the BTRFS_IOC_DEFRAG_RANGE
ioctl.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2016-04-28 11:06:41 +02:00
Jeff Mahoney 18db9ac644 btrfs: uapi/linux/btrfs.h migration, move feature flags
The compat/compat_ro/incompat feature flags are used by the feature set/get
ioctls.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2016-04-28 11:06:41 +02:00
Jeff Mahoney 83288b60bf btrfs: uapi/linux/btrfs.h migration, qgroup limit flags
The BTRFS_QGROUP_LIMIT_* flags are required to tell the kernel which
fields are valid when using the BTRFS_IOC_QGROUP_LIMIT ioctl.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2016-04-28 11:06:41 +02:00
Jeff Mahoney d4ae133b2d btrfs: uapi/linux/btrfs.h migration, move BTRFS_LABEL_SIZE
BTRFS_LABEL_SIZE is required to define the BTRFS_IOC_GET_FSLABEL and
BTRFS_IOC_SET_FSLABEL ioctls.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2016-04-28 11:06:41 +02:00
Luke Dashjr 4c63c2454e btrfs: bugfix: handle FS_IOC32_{GETFLAGS,SETFLAGS,GETVERSION} in btrfs_ioctl
32-bit ioctl uses these rather than the regular FS_IOC_* versions. They can
be handled in btrfs using the same code. Without this, 32-bit {ch,ls}attr
fail.

Signed-off-by: Luke Dashjr <luke-jr+git@utopios.org>
Cc: stable@vger.kernel.org
Reviewed-by: Josef Bacik <jbacik@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2016-04-28 10:40:27 +02:00
Anand Jain c5f4ccb2f7 btrfs: move error handling code together in ctree.h
Looks like we added the incompatible defines in between the error
handling defines in the file ctree.h. Now group them back.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2016-04-28 10:36:54 +02:00
Anand Jain 2351d743f6 btrfs: remove unused function btrfs_assert()
Apparently looks like ASSERT does the same intended job,
as intended btrfs_assert().

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2016-04-28 10:36:54 +02:00
Anand Jain 34d9700702 btrfs: rename btrfs_std_error to btrfs_handle_fs_error
btrfs_std_error() handles errors, puts FS into readonly mode
(as of now). So its good idea to rename it to btrfs_handle_fs_error().

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ edit changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
2016-04-28 10:36:54 +02:00
Adam Buchbinder bb7ab3b92e btrfs: Fix misspellings in comments.
Signed-off-by: Adam Buchbinder <adam.buchbinder@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2016-03-14 15:05:02 +01:00
Anand Jain ebb8765b2d btrfs: move btrfs_compression_type to compression.h
So that its better organized.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2016-03-11 17:12:46 +01:00
David Sterba f5bc27c71a Merge branch 'dev/control-ioctl' into for-chris-4.6 2016-02-26 15:38:34 +01:00
David Sterba fa695b01bc Merge branch 'misc-4.6' into for-chris-4.6
# Conflicts:
#	fs/btrfs/file.c
2016-02-26 15:38:34 +01:00
David Sterba f004fae0cf Merge branch 'cleanups-4.6' into for-chris-4.6 2016-02-26 15:38:33 +01:00
David Sterba 675d276b32 Merge branch 'foreign/liubo/replace-lockup' into for-chris-4.6 2016-02-26 15:38:32 +01:00
David Sterba ff7db6e05a Merge branch 'foreign/zhaolei/reada' into for-chris-4.6 2016-02-26 15:38:30 +01:00
David Sterba 23c1a966f2 Merge branch 'foreign/qu/norecovery-v7' into for-chris-4.6 2016-02-26 15:38:30 +01:00
David Sterba 67d605fec1 Merge branch 'dev/rename-keys' into for-chris-4.6 2016-02-26 15:38:29 +01:00
David Sterba 5f1b5664d9 Merge branch 'chandan/prep-subpage-blocksize' into for-chris-4.6
# Conflicts:
#	fs/btrfs/file.c
2016-02-26 15:38:28 +01:00
Liu Bo 73beece9ca Btrfs: fix lockdep deadlock warning due to dev_replace
Xfstests btrfs/011 complains about a deadlock warning,

[ 1226.649039] =========================================================
[ 1226.649039] [ INFO: possible irq lock inversion dependency detected ]
[ 1226.649039] 4.1.0+ #270 Not tainted
[ 1226.649039] ---------------------------------------------------------
[ 1226.652955] kswapd0/46 just changed the state of lock:
[ 1226.652955]  (&delayed_node->mutex){+.+.-.}, at: [<ffffffff81458735>] __btrfs_release_delayed_node+0x45/0x1d0
[ 1226.652955] but this lock took another, RECLAIM_FS-unsafe lock in the past:
[ 1226.652955]  (&fs_info->dev_replace.lock){+.+.+.}

and interrupts could create inverse lock ordering between them.

[ 1226.652955]
other info that might help us debug this:
[ 1226.652955] Chain exists of:
  &delayed_node->mutex --> &found->groups_sem --> &fs_info->dev_replace.lock

[ 1226.652955]  Possible interrupt unsafe locking scenario:

[ 1226.652955]        CPU0                    CPU1
[ 1226.652955]        ----                    ----
[ 1226.652955]   lock(&fs_info->dev_replace.lock);
[ 1226.652955]                                local_irq_disable();
[ 1226.652955]                                lock(&delayed_node->mutex);
[ 1226.652955]                                lock(&found->groups_sem);
[ 1226.652955]   <Interrupt>
[ 1226.652955]     lock(&delayed_node->mutex);
[ 1226.652955]
 *** DEADLOCK ***

Commit 084b6e7c76 ("btrfs: Fix a lockdep warning when running xfstest.") tried
to fix a similar one that has the exactly same warning, but with that, we still
run to this.

The above lock chain comes from
btrfs_commit_transaction
  ->btrfs_run_delayed_items
    ...
    ->__btrfs_update_delayed_inode
      ...
      ->__btrfs_cow_block
         ...
         ->find_free_extent
            ->cache_block_group
              ->load_free_space_cache
                ->btrfs_readpages
                  ->submit_one_bio
                    ...
                    ->__btrfs_map_block
                      ->btrfs_dev_replace_lock

However, with high memory pressure, tasks which hold dev_replace.lock can
be interrupted by kswapd and then kswapd is intended to release memory occupied
by superblock, inodes and dentries, where we may call evict_inode, and it comes
to

[ 1226.652955]  [<ffffffff81458735>] __btrfs_release_delayed_node+0x45/0x1d0
[ 1226.652955]  [<ffffffff81459e74>] btrfs_remove_delayed_node+0x24/0x30
[ 1226.652955]  [<ffffffff8140c5fe>] btrfs_evict_inode+0x34e/0x700

delayed_node->mutex may be acquired in __btrfs_release_delayed_node(), and it leads
to a ABBA deadlock.

To fix this, we can use "blocking rwlock" used in the case of extent_buffer, but
things are simpler here since we only needs read's spinlock to blocking lock.

With this, btrfs/011 no more produces warnings in dmesg.

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2016-02-23 13:10:10 +01:00
David Sterba d5131b658c btrfs: drop unused argument in btrfs_ioctl_get_supported_features
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2016-02-23 12:56:35 +01:00
David Sterba c5868f8362 btrfs: add GET_SUPPORTED_FEATURES to the control device ioctls
The control device is accessible when no filesystem is mounted and we
may want to query features supported by the module. This is already
possible using the sysfs files, this ioctl is for parity and
convenience.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2016-02-23 12:56:21 +01:00
David Sterba f7e98a7fff btrfs: change max_inline default to 2048
The current practical default is ~4k on x86_64 (the logic is more complex,
simplified for brevity), the inlined files land in the metadata group and
thus consume space that could be needed for the real metadata.

The inlining brings some usability surprises:

1) total space consumption measured on various filesystems and btrfs
   with DUP metadata was quite visible because of the duplicated data
   within metadata

2) inlined data may exhaust the metadata, which are more precious in case
   the entire device space is allocated to chunks (ie. balance cannot
   make the space more compact)

3) performance suffers a bit as the inlined blocks are duplicate and
   stored far away on the device.

Proposed fix: set the default to 2048

This fixes namely 1), the total filesysystem space consumption will be on
par with other filesystems.

Partially fixes 2), more data are pushed to the data block groups.

The characteristics of 3) are based on actual small file size
distribution.

The change is independent of the metadata blockgroup type (though it's
most visible with DUP) or system page size as these parameters are not
trival to find out, compared to file size.

Signed-off-by: David Sterba <dsterba@suse.com>
2016-02-23 12:55:27 +01:00
Byongho Lee 0138b6fe8f btrfs: simplify expression in btrfs_calc_trans_metadata_size()
Simplify expression in btrfs_calc_trans_metadata_size().

Signed-off-by: Byongho Lee <bhlee.kernel@gmail.com>
Reviewed-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: David Sterba <dsterba@suse.com>
2016-02-18 11:33:17 +01:00
Zhao Lei 2fefd5583f btrfs: reada: limit max works count
Reada creates 2 works for each level of tree recursively.

In case of a tree having many levels, the number of created works
is 2^level_of_tree.
Actually we don't need so many works in parallel, this patch limits
max works to BTRFS_MAX_MIRRORS * 2.

The per-fs works_counter will be also used for btrfs_reada_wait() to
check is there are background workers.

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2016-02-18 10:27:23 +01:00
Zhao Lei 02873e4325 btrfs: reada: Use fs_info instead of root in __readahead_hook's argument
What __readahead_hook() need exactly is fs_info, no need to convert
fs_info to root in caller and convert back in __readahead_hook()

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2016-02-18 10:26:12 +01:00
Qu Wenruo 96da09192c btrfs: Introduce new mount option to disable tree log replay
Introduce a new mount option "nologreplay" to co-operate with "ro" mount
option to get real readonly mount, like "norecovery" in ext* and xfs.

Since the new parse_options() need to check new flags at remount time,
so add a new parameter for parse_options().

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Reviewed-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Tested-by: Austin S. Hemmelgarn <ahferroin7@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2016-02-12 15:14:49 +01:00
Qu Wenruo 8dcddfa048 btrfs: Introduce new mount option usebackuproot to replace recovery
Current "recovery" mount option will only try to use backup root.
However the word "recovery" is too generic and may be confusing for some
users.

Here introduce a new and more specific mount option, "usebackuproot" to
replace "recovery" mount option.
"Recovery" will be kept for compatibility reason, but will be
deprecated.

Also, since "usebackuproot" will only affect mount behavior and after
open_ctree() it has nothing to do with the filesystem, so clear the flag
after mount succeeded.

This provides the basis for later unified "norecovery" mount option.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
[ dropped usebackuproot from show_mount, added note about 'recovery' to
  docs ]
Signed-off-by: David Sterba <dsterba@suse.com>
2016-02-12 15:14:14 +01:00
David Sterba 242e2956e4 btrfs: switch dev stats item to the permanent item key
Signed-off-by: David Sterba <dsterba@suse.com>
2016-02-11 16:15:43 +01:00
David Sterba 50c2d5abe6 btrfs: introduce key type for persistent permanent items
The number of distinct key types is not that big that we could waste one
for something new we want to store in the tree.

Similar to the temporary items, we'll introduce a new name for an
existing key value and use the objectid for further extension.  The
victim is the BTRFS_DEV_STATS_KEY (248).

The device stats are an example of a permanent item.

Signed-off-by: David Sterba <dsterba@suse.com>
2016-02-11 16:15:43 +01:00
David Sterba 0bbbccb17f btrfs: introduce key type for persistent temporary items
The number of distinct key types is not that big that we could waste one
for something new we want to store in the tree. We'll introduce a new
name for an existing key value and use the objectid for further
extension.  The victim is the BTRFS_BALANCE_ITEM_KEY (248).

The nature of the balance status item is a good example of the temporary
item. It exists from beginning of the balance, keeps the status until it
finishes.

Signed-off-by: David Sterba <dsterba@suse.com>
2016-02-11 16:15:43 +01:00
Chandan Rajendra 9703fefe0b Btrfs: fallocate: Work with sectorsized blocks
While at it, this commit changes btrfs_truncate_page() to truncate sectorsized
blocks instead of pages. Hence the function has been renamed to
btrfs_truncate_block().

Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2016-02-01 19:24:29 +01:00
Chandan Rajendra 2e78c927d7 Btrfs: __btrfs_buffered_write: Reserve/release extents aligned to block size
Currently, the code reserves/releases extents in multiples of PAGE_CACHE_SIZE
units. Fix this by doing reservation/releases in block size units.

Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2016-02-01 19:23:47 +01:00
Linus Torvalds 2101ae4289 Merge branch 'for-linus-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs
Pull more btrfs updates from Chris Mason:
 "These are mostly fixes that we've been testing, but also we grabbed
  and tested a few small cleanups that had been on the list for a while.

  Zhao Lei's patchset also fixes some early ENOSPC buglets"

* 'for-linus-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: (21 commits)
  btrfs: raid56: Use raid_write_end_io for scrub
  btrfs: Remove unnecessary ClearPageUptodate for raid56
  btrfs: use rbio->nr_pages to reduce calculation
  btrfs: Use unified stripe_page's index calculation
  btrfs: Fix calculation of rbio->dbitmap's size calculation
  btrfs: Fix no_space in write and rm loop
  btrfs: merge functions for wait snapshot creation
  btrfs: delete unused argument in btrfs_copy_from_user
  btrfs: Use direct way to determine raid56 write/recover mode
  btrfs: Small cleanup for get index_srcdev loop
  btrfs: Enhance chunk validation check
  btrfs: Enhance super validation check
  Btrfs: fix deadlock running delayed iputs at transaction commit time
  Btrfs: fix typo in log message when starting a balance
  btrfs: remove duplicate const specifier
  btrfs: initialize the seq counter in struct btrfs_device
  Btrfs: clean up an error code in btrfs_init_space_info()
  btrfs: fix iterator with update error in backref.c
  Btrfs: fix output of compression message in btrfs_parse_options()
  Btrfs: Initialize btrfs_root->highest_objectid when loading tree root and subvolume roots
  ...
2016-01-22 11:49:21 -08:00
Zhao Lei 0bc19f9031 btrfs: merge functions for wait snapshot creation
wait_for_snapshot_creation() is in same group with oher two:
 btrfs_start_write_no_snapshoting()
 btrfs_end_write_no_snapshoting()

Rename wait_for_snapshot_creation() and move it into same place
with other two.

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
2016-01-20 07:22:13 -08:00
Filipe Manana c2d6cb1636 Btrfs: fix deadlock running delayed iputs at transaction commit time
While running a stress test I ran into a deadlock when running the delayed
iputs at transaction time, which produced the following report and trace:

[  886.399989] =============================================
[  886.400871] [ INFO: possible recursive locking detected ]
[  886.401663] 4.4.0-rc6-btrfs-next-18+ #1 Not tainted
[  886.402384] ---------------------------------------------
[  886.403182] fio/8277 is trying to acquire lock:
[  886.403568]  (&fs_info->delayed_iput_sem){++++..}, at: [<ffffffffa0538823>] btrfs_run_delayed_iputs+0x36/0xbf [btrfs]
[  886.403568]
[  886.403568] but task is already holding lock:
[  886.403568]  (&fs_info->delayed_iput_sem){++++..}, at: [<ffffffffa0538823>] btrfs_run_delayed_iputs+0x36/0xbf [btrfs]
[  886.403568]
[  886.403568] other info that might help us debug this:
[  886.403568]  Possible unsafe locking scenario:
[  886.403568]
[  886.403568]        CPU0
[  886.403568]        ----
[  886.403568]   lock(&fs_info->delayed_iput_sem);
[  886.403568]   lock(&fs_info->delayed_iput_sem);
[  886.403568]
[  886.403568]  *** DEADLOCK ***
[  886.403568]
[  886.403568]  May be due to missing lock nesting notation
[  886.403568]
[  886.403568] 3 locks held by fio/8277:
[  886.403568]  #0:  (sb_writers#11){.+.+.+}, at: [<ffffffff81174c4c>] __sb_start_write+0x5f/0xb0
[  886.403568]  #1:  (&sb->s_type->i_mutex_key#15){+.+.+.}, at: [<ffffffffa054620d>] btrfs_file_write_iter+0x73/0x408 [btrfs]
[  886.403568]  #2:  (&fs_info->delayed_iput_sem){++++..}, at: [<ffffffffa0538823>] btrfs_run_delayed_iputs+0x36/0xbf [btrfs]
[  886.403568]
[  886.403568] stack backtrace:
[  886.403568] CPU: 6 PID: 8277 Comm: fio Not tainted 4.4.0-rc6-btrfs-next-18+ #1
[  886.403568] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS by qemu-project.org 04/01/2014
[  886.403568]  0000000000000000 ffff88009f80f770 ffffffff8125d4fd ffffffff82af1fc0
[  886.403568]  ffff88009f80f830 ffffffff8108e5f9 0000000200000000 ffff88009fd92290
[  886.403568]  0000000000000000 ffffffff82af1fc0 ffffffff829cfb01 00042b216d008804
[  886.403568] Call Trace:
[  886.403568]  [<ffffffff8125d4fd>] dump_stack+0x4e/0x79
[  886.403568]  [<ffffffff8108e5f9>] __lock_acquire+0xd42/0xf0b
[  886.403568]  [<ffffffff810c22db>] ? __module_address+0xdf/0x108
[  886.403568]  [<ffffffff8108eb77>] lock_acquire+0x10d/0x194
[  886.403568]  [<ffffffff8108eb77>] ? lock_acquire+0x10d/0x194
[  886.403568]  [<ffffffffa0538823>] ? btrfs_run_delayed_iputs+0x36/0xbf [btrfs]
[  886.489542]  [<ffffffff8148556b>] down_read+0x3e/0x4d
[  886.489542]  [<ffffffffa0538823>] ? btrfs_run_delayed_iputs+0x36/0xbf [btrfs]
[  886.489542]  [<ffffffffa0538823>] btrfs_run_delayed_iputs+0x36/0xbf [btrfs]
[  886.489542]  [<ffffffffa0533953>] btrfs_commit_transaction+0x8f5/0x96e [btrfs]
[  886.489542]  [<ffffffffa0521d7a>] flush_space+0x435/0x44a [btrfs]
[  886.489542]  [<ffffffffa052218b>] ? reserve_metadata_bytes+0x26a/0x384 [btrfs]
[  886.489542]  [<ffffffffa05221ae>] reserve_metadata_bytes+0x28d/0x384 [btrfs]
[  886.489542]  [<ffffffffa052256c>] ? btrfs_block_rsv_refill+0x58/0x96 [btrfs]
[  886.489542]  [<ffffffffa0522584>] btrfs_block_rsv_refill+0x70/0x96 [btrfs]
[  886.489542]  [<ffffffffa053d747>] btrfs_evict_inode+0x394/0x55a [btrfs]
[  886.489542]  [<ffffffff81188e31>] evict+0xa7/0x15c
[  886.489542]  [<ffffffff81189878>] iput+0x1d3/0x266
[  886.489542]  [<ffffffffa053887c>] btrfs_run_delayed_iputs+0x8f/0xbf [btrfs]
[  886.489542]  [<ffffffffa0533953>] btrfs_commit_transaction+0x8f5/0x96e [btrfs]
[  886.489542]  [<ffffffff81085096>] ? signal_pending_state+0x31/0x31
[  886.489542]  [<ffffffffa0521191>] btrfs_alloc_data_chunk_ondemand+0x1d7/0x288 [btrfs]
[  886.489542]  [<ffffffffa0521282>] btrfs_check_data_free_space+0x40/0x59 [btrfs]
[  886.489542]  [<ffffffffa05228f5>] btrfs_delalloc_reserve_space+0x1e/0x4e [btrfs]
[  886.489542]  [<ffffffffa053620a>] btrfs_direct_IO+0x10c/0x27e [btrfs]
[  886.489542]  [<ffffffff8111d9a1>] generic_file_direct_write+0xb3/0x128
[  886.489542]  [<ffffffffa05463c3>] btrfs_file_write_iter+0x229/0x408 [btrfs]
[  886.489542]  [<ffffffff8108ae38>] ? __lock_is_held+0x38/0x50
[  886.489542]  [<ffffffff8117279e>] __vfs_write+0x7c/0xa5
[  886.489542]  [<ffffffff81172cda>] vfs_write+0xa0/0xe4
[  886.489542]  [<ffffffff811734cc>] SyS_write+0x50/0x7e
[  886.489542]  [<ffffffff814872d7>] entry_SYSCALL_64_fastpath+0x12/0x6f
[ 1081.852335] INFO: task fio:8244 blocked for more than 120 seconds.
[ 1081.854348]       Not tainted 4.4.0-rc6-btrfs-next-18+ #1
[ 1081.857560] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 1081.863227] fio        D ffff880213f9bb28     0  8244   8240 0x00000000
[ 1081.868719]  ffff880213f9bb28 00ffffff810fc6b0 ffffffff0000000a ffff88023ed55240
[ 1081.872499]  ffff880206b5d400 ffff880213f9c000 ffff88020a4d5318 ffff880206b5d400
[ 1081.876834]  ffffffff00000001 ffff880206b5d400 ffff880213f9bb40 ffffffff81482ba4
[ 1081.880782] Call Trace:
[ 1081.881793]  [<ffffffff81482ba4>] schedule+0x7f/0x97
[ 1081.883340]  [<ffffffff81485eb5>] rwsem_down_write_failed+0x2d5/0x325
[ 1081.895525]  [<ffffffff8108d48d>] ? trace_hardirqs_on_caller+0x16/0x1ab
[ 1081.897419]  [<ffffffff81269723>] call_rwsem_down_write_failed+0x13/0x20
[ 1081.899251]  [<ffffffff81269723>] ? call_rwsem_down_write_failed+0x13/0x20
[ 1081.901063]  [<ffffffff81089fae>] ? __down_write_nested.isra.0+0x1f/0x21
[ 1081.902365]  [<ffffffff814855bd>] down_write+0x43/0x57
[ 1081.903846]  [<ffffffffa05211b0>] ? btrfs_alloc_data_chunk_ondemand+0x1f6/0x288 [btrfs]
[ 1081.906078]  [<ffffffffa05211b0>] btrfs_alloc_data_chunk_ondemand+0x1f6/0x288 [btrfs]
[ 1081.908846]  [<ffffffff8108d461>] ? mark_held_locks+0x56/0x6c
[ 1081.910409]  [<ffffffffa0521282>] btrfs_check_data_free_space+0x40/0x59 [btrfs]
[ 1081.912482]  [<ffffffffa05228f5>] btrfs_delalloc_reserve_space+0x1e/0x4e [btrfs]
[ 1081.914597]  [<ffffffffa053620a>] btrfs_direct_IO+0x10c/0x27e [btrfs]
[ 1081.919037]  [<ffffffff8111d9a1>] generic_file_direct_write+0xb3/0x128
[ 1081.920754]  [<ffffffffa05463c3>] btrfs_file_write_iter+0x229/0x408 [btrfs]
[ 1081.922496]  [<ffffffff8108ae38>] ? __lock_is_held+0x38/0x50
[ 1081.923922]  [<ffffffff8117279e>] __vfs_write+0x7c/0xa5
[ 1081.925275]  [<ffffffff81172cda>] vfs_write+0xa0/0xe4
[ 1081.926584]  [<ffffffff811734cc>] SyS_write+0x50/0x7e
[ 1081.927968]  [<ffffffff814872d7>] entry_SYSCALL_64_fastpath+0x12/0x6f
[ 1081.985293] INFO: lockdep is turned off.
[ 1081.986132] INFO: task fio:8249 blocked for more than 120 seconds.
[ 1081.987434]       Not tainted 4.4.0-rc6-btrfs-next-18+ #1
[ 1081.988534] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 1081.990147] fio        D ffff880218febbb8     0  8249   8240 0x00000000
[ 1081.991626]  ffff880218febbb8 00ffffff81486b8e ffff88020000000b ffff88023ed75240
[ 1081.993258]  ffff8802120a9a00 ffff880218fec000 ffff88020a4d5318 ffff8802120a9a00
[ 1081.994850]  ffffffff00000001 ffff8802120a9a00 ffff880218febbd0 ffffffff81482ba4
[ 1081.996485] Call Trace:
[ 1081.997037]  [<ffffffff81482ba4>] schedule+0x7f/0x97
[ 1081.998017]  [<ffffffff81485eb5>] rwsem_down_write_failed+0x2d5/0x325
[ 1081.999241]  [<ffffffff810852a5>] ? finish_wait+0x6d/0x76
[ 1082.000306]  [<ffffffff81269723>] call_rwsem_down_write_failed+0x13/0x20
[ 1082.001533]  [<ffffffff81269723>] ? call_rwsem_down_write_failed+0x13/0x20
[ 1082.002776]  [<ffffffff81089fae>] ? __down_write_nested.isra.0+0x1f/0x21
[ 1082.003995]  [<ffffffff814855bd>] down_write+0x43/0x57
[ 1082.005000]  [<ffffffffa05211b0>] ? btrfs_alloc_data_chunk_ondemand+0x1f6/0x288 [btrfs]
[ 1082.007403]  [<ffffffffa05211b0>] btrfs_alloc_data_chunk_ondemand+0x1f6/0x288 [btrfs]
[ 1082.008988]  [<ffffffffa0545064>] btrfs_fallocate+0x7c1/0xc2f [btrfs]
[ 1082.010193]  [<ffffffff8108a1ba>] ? percpu_down_read+0x4e/0x77
[ 1082.011280]  [<ffffffff81174c4c>] ? __sb_start_write+0x5f/0xb0
[ 1082.012265]  [<ffffffff81174c4c>] ? __sb_start_write+0x5f/0xb0
[ 1082.013021]  [<ffffffff811712e4>] vfs_fallocate+0x170/0x1ff
[ 1082.013738]  [<ffffffff81181ebb>] ioctl_preallocate+0x89/0x9b
[ 1082.014778]  [<ffffffff811822d7>] do_vfs_ioctl+0x40a/0x4ea
[ 1082.015778]  [<ffffffff81176ea7>] ? SYSC_newfstat+0x25/0x2e
[ 1082.016806]  [<ffffffff8118b4de>] ? __fget_light+0x4d/0x71
[ 1082.017789]  [<ffffffff8118240e>] SyS_ioctl+0x57/0x79
[ 1082.018706]  [<ffffffff814872d7>] entry_SYSCALL_64_fastpath+0x12/0x6f

This happens because we can recursively acquire the semaphore
fs_info->delayed_iput_sem when attempting to allocate space to satisfy
a file write request as shown in the first trace above - when committing
a transaction we acquire (down_read) the semaphore before running the
delayed iputs, and when running a delayed iput() we can end up calling
an inode's eviction handler, which in turn commits another transaction
and attempts to acquire (down_read) again the semaphore to run more
delayed iput operations.
This results in a deadlock because if a task acquires multiple times a
semaphore it should invoke down_read_nested() with a different lockdep
class for each level of recursion.

Fix this by simplifying the implementation and use a mutex instead that
is acquired by the cleaner kthread before it runs the delayed iputs
instead of always acquiring a semaphore before delayed references are
run from anywhere.

Fixes: d7c151717a (btrfs: Fix NO_SPACE bug caused by delayed-iput)
Cc: stable@vger.kernel.org   # 4.1+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
2016-01-19 18:21:41 -08:00
Linus Torvalds c1a198d923 Merge branch 'for-linus-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs
Pull btrfs updates from Chris Mason:
 "This has our usual assortment of fixes and cleanups, but the biggest
  change included is Omar Sandoval's free space tree.  It's not the
  default yet, mounting -o space_cache=v2 enables it and sets a readonly
  compat bit.  The tree can actually be deleted and regenerated if there
  are any problems, but it has held up really well in testing so far.

  For very large filesystems (30T+) our existing free space caching code
  can end up taking a huge amount of time during commits.  The new tree
  based code is faster and less work overall to update as the commit
  progresses.

  Omar worked on this during the summer and we'll hammer on it in
  production here at FB over the next few months"

* 'for-linus-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: (73 commits)
  Btrfs: fix fitrim discarding device area reserved for boot loader's use
  Btrfs: Check metadata redundancy on balance
  btrfs: statfs: report zero available if metadata are exhausted
  btrfs: preallocate path for snapshot creation at ioctl time
  btrfs: allocate root item at snapshot ioctl time
  btrfs: do an allocation earlier during snapshot creation
  btrfs: use smaller type for btrfs_path locks
  btrfs: use smaller type for btrfs_path lowest_level
  btrfs: use smaller type for btrfs_path reada
  btrfs: cleanup, use enum values for btrfs_path reada
  btrfs: constify static arrays
  btrfs: constify remaining structs with function pointers
  btrfs tests: replace whole ops structure for free space tests
  btrfs: use list_for_each_entry* in backref.c
  btrfs: use list_for_each_entry_safe in free-space-cache.c
  btrfs: use list_for_each_entry* in check-integrity.c
  Btrfs: use linux/sizes.h to represent constants
  btrfs: cleanup, remove stray return statements
  btrfs: zero out delayed node upon allocation
  btrfs: pass proper enum type to start_transaction()
  ...
2016-01-18 12:44:40 -08:00
Chris Mason b28cf57246 Merge branch 'misc-cleanups-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux into for-linus-4.5
Signed-off-by: Chris Mason <clm@fb.com>
2016-01-11 06:08:37 -08:00
Chris Mason a3058101c1 Merge branch 'misc-for-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux into for-linus-4.5 2016-01-11 05:59:32 -08:00
David Sterba 4fb72bf2e9 btrfs: use smaller type for btrfs_path locks
The values of btrfs_path::locks are 0 to 4, fit into a u8. Let's see:

* overall size of btrfs_path drops down from 136 to 112 (-24 bytes),
* better packing in a slab page +6 objects
* the whole structure now fits to 2 cachelines
* slight decrease in code size:

   text    data     bss     dec     hex filename
 938731   43670   23144 1005545   f57e9 fs/btrfs/btrfs.ko.before
 938203   43670   23144 1005017   f55d9 fs/btrfs/btrfs.ko.after

(and the generated assembly does not change much)

The main purpose is to decrease the size of the structure without
affecting performance. The byte access is usually well behaving accross
arches, the locks are not accessed frequently and sometimes just
compared to zero.

Note for further size reduction attempts: the slots could be made u16
but this might generate worse code on some arches (non-byte and non-int
access). Also the range of operations on slots is wider compared to
locks and the potential performance drop should be evaluated first.

Signed-off-by: David Sterba <dsterba@suse.com>
2016-01-07 15:01:17 +01:00
David Sterba 7853f15b2a btrfs: use smaller type for btrfs_path lowest_level
The level is 0..7, we can use smaller type. The size of btrfs_path is now
136 bytes from 144, which is +2 objects that fit into a 4k slab.

Signed-off-by: David Sterba <dsterba@suse.com>
2016-01-07 15:01:17 +01:00
David Sterba dccabfad20 btrfs: use smaller type for btrfs_path reada
The possible values for reada are all positive and bounded, we can later
save some bytes by storing it in u8.

Signed-off-by: David Sterba <dsterba@suse.com>
2016-01-07 15:01:16 +01:00
David Sterba e4058b54d1 btrfs: cleanup, use enum values for btrfs_path reada
Replace the integers by enums for better readability. The value 2 does
not have any meaning since a717531942
"Btrfs: do less aggressive btree readahead" (2009-01-22).

Signed-off-by: David Sterba <dsterba@suse.com>
2016-01-07 15:01:15 +01:00
David Sterba 4d4ab6d6bc btrfs: constify static arrays
There are a few statically initialized arrays that can be made const.
The remaining (like file_system_type, sysfs attributes or prop handlers)
do not allow that due to type mismatch when passed to the APIs or
because the structures are modified through other members.

Signed-off-by: David Sterba <dsterba@suse.com>
2016-01-07 15:01:15 +01:00
Byongho Lee ee22184b53 Btrfs: use linux/sizes.h to represent constants
We use many constants to represent size and offset value.  And to make
code readable we use '256 * 1024 * 1024' instead of '268435456' to
represent '256MB'.  However we can make far more readable with 'SZ_256MB'
which is defined in the 'linux/sizes.h'.

So this patch replaces 'xxx * 1024 * 1024' kind of expression with
single 'SZ_xxxMB' if 'xxx' is a power of 2 then 'xxx * SZ_1M' if 'xxx' is
not a power of 2. And I haven't touched to '4096' & '8192' because it's
more intuitive than 'SZ_4KB' & 'SZ_8KB'.

Signed-off-by: Byongho Lee <bhlee.kernel@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2016-01-07 14:38:02 +01:00
Alexandru Moise 9780c4976f btrfs: switch __btrfs_fs_incompat return type from int to bool
Conform to __btrfs_fs_incompat() cast-to-bool (!!) by explicitly
returning boolean not int.

Signed-off-by: Alexandru Moise <00moses.alexander00@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2016-01-07 14:29:20 +01:00
Darrick J. Wong 2b3909f8a7 btrfs: use new dedupe data function pointer
Now that the VFS encapsulates the dedupe ioctl, wire up btrfs to it.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-01-01 02:36:40 -05:00
Chris Mason 511711af91 btrfs: don't run delayed references while we are creating the free space tree
This is a short term solution to make sure btrfs_run_delayed_refs()
doesn't change the extent tree while we are scanning it to create the
free space tree.

Longer term we need to synchronize scanning the block groups one by one,
similar to what happens during a balance.

Signed-off-by: Chris Mason <clm@fb.com>
2015-12-30 07:52:35 -08:00
Chris Mason f0f76413d3 Merge branch 'freespace-4.5' into for-linus-4.5 2015-12-23 13:29:09 -08:00
Chris Mason afa427cf9d Merge branch 'cleanup/misc-simplify' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux into for-linus-4.5 2015-12-23 13:10:26 -08:00
Chris Mason f7d3d2f99e Merge branch 'freespace-tree' into for-linus-4.5
Signed-off-by: Chris Mason <clm@fb.com>
2015-12-18 11:11:10 -08:00
Omar Sandoval 70f6d82ec7 Btrfs: add free space tree mount option
Now we can finally hook up everything so we can actually use free space
tree. The free space tree is enabled by passing the space_cache=v2 mount
option. On the first mount with the this option set, the free space tree
will be created and the FREE_SPACE_TREE read-only compat bit will be
set. Any time the filesystem is mounted from then on, we must use the
free space tree. The clear_cache option will also clear the free space
tree.

Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-12-17 12:16:47 -08:00
Omar Sandoval a5ed918285 Btrfs: implement the free space B-tree
The free space cache has turned out to be a scalability bottleneck on
large, busy filesystems. When the cache for a lot of block groups needs
to be written out, we can get extremely long commit times; if this
happens in the critical section, things are especially bad because we
block new transactions from happening.

The main problem with the free space cache is that it has to be written
out in its entirety and is managed in an ad hoc fashion. Using a B-tree
to store free space fixes this: updates can be done as needed and we get
all of the benefits of using a B-tree: checksumming, RAID handling,
well-understood behavior.

With the free space tree, we get commit times that are about the same as
the no cache case with load times slower than the free space cache case
but still much faster than the no cache case. Free space is represented
with extents until it becomes more space-efficient to use bitmaps,
giving us similar space overhead to the free space cache.

The operations on the free space tree are: adding and removing free
space, handling the creation and deletion of block groups, and loading
the free space for a block group. We can also create the free space tree
by walking the extent tree and clear the free space tree.

Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-12-17 12:16:47 -08:00
Omar Sandoval 208acb8c72 Btrfs: introduce the free space B-tree on-disk format
The on-disk format for the free space tree is straightforward. Each
block group is represented in the free space tree by a free space info
item that stores accounting information: whether the free space for this
block group is stored as bitmaps or extents and how many extents of free
space exist for this block group (regardless of which format is being
used in the tree). Extents are (start, FREE_SPACE_EXTENT, length) keys
with no corresponding item, and bitmaps instead have the
FREE_SPACE_BITMAP type and have a bitmap item attached, which is just an
array of bytes.

Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-12-17 12:16:46 -08:00
Omar Sandoval 73fa48b674 Btrfs: refactor caching_thread()
We're also going to load the free space tree from caching_thread(), so
we should refactor some of the common code.

Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-12-17 12:16:46 -08:00
Omar Sandoval 1abfbcdf56 Btrfs: add helpers for read-only compat bits
We're finally going to add one of these for the free space tree, so
let's add the same nice helpers that we have for the incompat bits.
While we're add it, also add helpers to clear the bits.

Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-12-17 12:16:46 -08:00
Christoph Hellwig 04b38d6012 vfs: pull btrfs clone API to vfs layer
The btrfs clone ioctls are now adopted by other file systems, with NFS
and CIFS already having support for them, and XFS being under active
development.  To avoid growth of various slightly incompatible
implementations, add one to the VFS.  Note that clones are different from
file copies in several ways:

 - they are atomic vs other writers
 - they support whole file clones
 - they support 64-bit legth clones
 - they do not allow partial success (aka short writes)
 - clones are expected to be a fast metadata operation

Because of that it would be rather cumbersome to try to piggyback them on
top of the recent clone_file_range infrastructure.  The converse isn't
true and the clone_file_range system call could try clone file range as
a first attempt to copy, something that further patches will enable.

Based on earlier work from Peng Tao.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-12-07 23:11:33 -05:00
David Sterba 3042460136 btrfs: remove wait from struct btrfs_delalloc_work
The value is 0 and never changes, we can propagate the value, remove
wait and the implied dead code.

Signed-off-by: David Sterba <dsterba@suse.com>
2015-12-03 15:02:21 +01:00
David Sterba 651d494a67 btrfs: sink parameter wait to btrfs_alloc_delalloc_work
There's only one caller and single value, we can propagate it down to
the callee and remove the unused parameter.

Signed-off-by: David Sterba <dsterba@suse.com>
2015-12-03 15:02:21 +01:00
Zach Brown 3db11b2eec btrfs: add .copy_file_range file operation
This rearranges the existing COPY_RANGE ioctl implementation so that the
.copy_file_range file operation can call the core loop that copies file
data extent items.

The extent copying loop is lifted up into its own function.  It retains
the core btrfs error checks that should be shared.

Signed-off-by: Zach Brown <zab@redhat.com>
[Anna Schumaker: Make flags an unsigned int,
                 Check for COPY_FR_REFLINK]
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-12-01 14:00:54 -05:00
Linus Torvalds 80e0c505b2 Merge branch 'for-linus-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs
Pull btrfs fixes from Chris Mason:
 "This has Mark Fasheh's patches to fix quota accounting during subvol
  deletion, which we've been working on for a while now.  The patch is
  pretty small but it's a key fix.

  Otherwise it's a random assortment"

* 'for-linus-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  btrfs: fix balance range usage filters in 4.4-rc
  btrfs: qgroup: account shared subtree during snapshot delete
  Btrfs: use btrfs_get_fs_root in resolve_indirect_ref
  btrfs: qgroup: fix quota disable during rescan
  Btrfs: fix race between cleaner kthread and space cache writeout
  Btrfs: fix scrub preventing unused block groups from being deleted
  Btrfs: fix race between scrub and block group deletion
  btrfs: fix rcu warning during device replace
  btrfs: Continue replace when set_block_ro failed
  btrfs: fix clashing number of the enhanced balance usage filter
  Btrfs: fix the number of transaction units needed to remove a block group
  Btrfs: use global reserve when deleting unused block group after ENOSPC
  Btrfs: tests: checking for NULL instead of IS_ERR()
  btrfs: fix signed overflows in btrfs_sync_file
2015-11-27 15:45:45 -08:00
Filipe Manana 758f2dfcf8 Btrfs: fix scrub preventing unused block groups from being deleted
Currently scrub can race with the cleaner kthread when the later attempts
to delete an unused block group, and the result is preventing the cleaner
kthread from ever deleting later the block group - unless the block group
becomes used and unused again. The following diagram illustrates that
race:

              CPU 1                                 CPU 2

 cleaner kthread
   btrfs_delete_unused_bgs()

     gets block group X from
     fs_info->unused_bgs and
     removes it from that list

                                             scrub_enumerate_chunks()

                                               searches device tree using
                                               its commit root

                                               finds device extent for
                                               block group X

                                               gets block group X from the tree
                                               fs_info->block_group_cache_tree
                                               (via btrfs_lookup_block_group())

                                               sets bg X to RO

     sees the block group is
     already RO and therefore
     doesn't delete it nor adds
     it back to unused list

So fix this by making scrub add the block group again to the list of
unused block groups if the block group is still unused when it finished
scrubbing it and it hasn't been removed already.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-11-25 05:22:08 -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
Linus Torvalds ad804a0b2a Merge branch 'akpm' (patches from Andrew)
Merge second patch-bomb from Andrew Morton:

 - most of the rest of MM

 - procfs

 - lib/ updates

 - printk updates

 - bitops infrastructure tweaks

 - checkpatch updates

 - nilfs2 update

 - signals

 - various other misc bits: coredump, seqfile, kexec, pidns, zlib, ipc,
   dma-debug, dma-mapping, ...

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (102 commits)
  ipc,msg: drop dst nil validation in copy_msg
  include/linux/zutil.h: fix usage example of zlib_adler32()
  panic: release stale console lock to always get the logbuf printed out
  dma-debug: check nents in dma_sync_sg*
  dma-mapping: tidy up dma_parms default handling
  pidns: fix set/getpriority and ioprio_set/get in PRIO_USER mode
  kexec: use file name as the output message prefix
  fs, seqfile: always allow oom killer
  seq_file: reuse string_escape_str()
  fs/seq_file: use seq_* helpers in seq_hex_dump()
  coredump: change zap_threads() and zap_process() to use for_each_thread()
  coredump: ensure all coredumping tasks have SIGNAL_GROUP_COREDUMP
  signal: remove jffs2_garbage_collect_thread()->allow_signal(SIGCONT)
  signal: introduce kernel_signal_stop() to fix jffs2_garbage_collect_thread()
  signal: turn dequeue_signal_lock() into kernel_dequeue_signal()
  signals: kill block_all_signals() and unblock_all_signals()
  nilfs2: fix gcc uninitialized-variable warnings in powerpc build
  nilfs2: fix gcc unused-but-set-variable warnings
  MAINTAINERS: nilfs2: add header file for tracing
  nilfs2: add tracepoints for analyzing reading and writing metadata files
  ...
2015-11-07 14:32:45 -08:00
Michal Hocko c62d25556b mm, fs: introduce mapping_gfp_constraint()
There are many places which use mapping_gfp_mask to restrict a more
generic gfp mask which would be used for allocations which are not
directly related to the page cache but they are performed in the same
context.

Let's introduce a helper function which makes the restriction explicit and
easier to track.  This patch doesn't introduce any functional changes.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Michal Hocko <mhocko@suse.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06 17:50:42 -08:00
Qu Wenruo 5846a3c268 btrfs: qgroup: Fix a race in delayed_ref which leads to abort trans
Between btrfs_allocerved_file_extent() and
btrfs_add_delayed_qgroup_reserve(), there is a window that delayed_refs
are run and delayed ref head maybe freed before
btrfs_add_delayed_qgroup_reserve().

This will cause btrfs_dad_delayed_qgroup_reserve() to return -ENOENT,
and cause transaction to be aborted.

This patch will record qgroup reserve space info into delayed_ref_head
at btrfs_add_delayed_ref(), to eliminate the race window.

Reported-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-10-26 19:44:39 -07:00
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
Filipe Manana b06c4bf5c8 Btrfs: fix regression running delayed references when using qgroups
In the kernel 4.2 merge window we had a big changes to the implementation
of delayed references and qgroups which made the no_quota field of delayed
references not used anymore. More specifically the no_quota field is not
used anymore as of:

  commit 0ed4792af0 ("btrfs: qgroup: Switch to new extent-oriented qgroup mechanism.")

Leaving the no_quota field actually prevents delayed references from
getting merged, which in turn cause the following BUG_ON(), at
fs/btrfs/extent-tree.c, to be hit when qgroups are enabled:

  static int run_delayed_tree_ref(...)
  {
     (...)
     BUG_ON(node->ref_mod != 1);
     (...)
  }

This happens on a scenario like the following:

  1) Ref1 bytenr X, action = BTRFS_ADD_DELAYED_REF, no_quota = 1, added.

  2) Ref2 bytenr X, action = BTRFS_DROP_DELAYED_REF, no_quota = 0, added.
     It's not merged with Ref1 because Ref1->no_quota != Ref2->no_quota.

  3) Ref3 bytenr X, action = BTRFS_ADD_DELAYED_REF, no_quota = 1, added.
     It's not merged with the reference at the tail of the list of refs
     for bytenr X because the reference at the tail, Ref2 is incompatible
     due to Ref2->no_quota != Ref3->no_quota.

  4) Ref4 bytenr X, action = BTRFS_DROP_DELAYED_REF, no_quota = 0, added.
     It's not merged with the reference at the tail of the list of refs
     for bytenr X because the reference at the tail, Ref3 is incompatible
     due to Ref3->no_quota != Ref4->no_quota.

  5) We run delayed references, trigger merging of delayed references,
     through __btrfs_run_delayed_refs() -> btrfs_merge_delayed_refs().

  6) Ref1 and Ref3 are merged as Ref1->no_quota = Ref3->no_quota and
     all other conditions are satisfied too. So Ref1 gets a ref_mod
     value of 2.

  7) Ref2 and Ref4 are merged as Ref2->no_quota = Ref4->no_quota and
     all other conditions are satisfied too. So Ref2 gets a ref_mod
     value of 2.

  8) Ref1 and Ref2 aren't merged, because they have different values
     for their no_quota field.

  9) Delayed reference Ref1 is picked for running (select_delayed_ref()
     always prefers references with an action == BTRFS_ADD_DELAYED_REF).
     So run_delayed_tree_ref() is called for Ref1 which triggers the
     BUG_ON because Ref1->red_mod != 1 (equals 2).

So fix this by removing the no_quota field, as it's not used anymore as
of commit 0ed4792af0 ("btrfs: qgroup: Switch to new extent-oriented
qgroup mechanism.").

The use of no_quota was also buggy in at least two places:

1) At delayed-refs.c:btrfs_add_delayed_tree_ref() - we were setting
   no_quota to 0 instead of 1 when the following condition was true:
   is_fstree(ref_root) || !fs_info->quota_enabled

2) At extent-tree.c:__btrfs_inc_extent_ref() - we were attempting to
   reset a node's no_quota when the condition "!is_fstree(root_objectid)
   || !root->fs_info->quota_enabled" was true but we did it only in
   an unused local stack variable, that is, we never reset the no_quota
   value in the node itself.

This fixes the remainder of problems several people have been having when
running delayed references, mostly while a balance is running in parallel,
on a 4.2+ kernel.

Very special thanks to Stéphane Lesimple for helping debugging this issue
and testing this fix on his multi terabyte filesystem (which took more
than one day to balance alone, plus fsck, etc).

Also, this fixes deadlock issue when using the clone ioctl with qgroups
enabled, as reported by Elias Probst in the mailing list. The deadlock
happens because after calling btrfs_insert_empty_item we have our path
holding a write lock on a leaf of the fs/subvol tree and then before
releasing the path we called check_ref() which did backref walking, when
qgroups are enabled, and tried to read lock the same leaf. The trace for
this case is the following:

  INFO: task systemd-nspawn:6095 blocked for more than 120 seconds.
  (...)
  Call Trace:
    [<ffffffff86999201>] schedule+0x74/0x83
    [<ffffffff863ef64c>] btrfs_tree_read_lock+0xc0/0xea
    [<ffffffff86137ed7>] ? wait_woken+0x74/0x74
    [<ffffffff8639f0a7>] btrfs_search_old_slot+0x51a/0x810
    [<ffffffff863a129b>] btrfs_next_old_leaf+0xdf/0x3ce
    [<ffffffff86413a00>] ? ulist_add_merge+0x1b/0x127
    [<ffffffff86411688>] __resolve_indirect_refs+0x62a/0x667
    [<ffffffff863ef546>] ? btrfs_clear_lock_blocking_rw+0x78/0xbe
    [<ffffffff864122d3>] find_parent_nodes+0xaf3/0xfc6
    [<ffffffff86412838>] __btrfs_find_all_roots+0x92/0xf0
    [<ffffffff864128f2>] btrfs_find_all_roots+0x45/0x65
    [<ffffffff8639a75b>] ? btrfs_get_tree_mod_seq+0x2b/0x88
    [<ffffffff863e852e>] check_ref+0x64/0xc4
    [<ffffffff863e9e01>] btrfs_clone+0x66e/0xb5d
    [<ffffffff863ea77f>] btrfs_ioctl_clone+0x48f/0x5bb
    [<ffffffff86048a68>] ? native_sched_clock+0x28/0x77
    [<ffffffff863ed9b0>] btrfs_ioctl+0xabc/0x25cb
  (...)

The problem goes away by eleminating check_ref(), which no longer is
needed as its purpose was to get a value for the no_quota field of
a delayed reference (this patch removes the no_quota field as mentioned
earlier).

Reported-by: Stéphane Lesimple <stephane_btrfs@lesimple.fr>
Tested-by: Stéphane Lesimple <stephane_btrfs@lesimple.fr>
Reported-by: Elias Probst <mail@eliasprobst.eu>
Reported-by: Peter Becker <floyd.net@gmail.com>
Reported-by: Malte Schröder <malte@tnxip.de>
Reported-by: Derek Dongray <derek@valedon.co.uk>
Reported-by: Erkki Seppala <flux-btrfs@inside.org>
Cc: stable@vger.kernel.org  # 4.2+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
2015-10-25 19:53:26 +00:00
Chris Mason a9e6d15356 Merge branch 'allocator-fixes' into for-linus-4.4
Signed-off-by: Chris Mason <clm@fb.com>
2015-10-21 19:00:38 -07:00
Josef Bacik c759c4e161 Btrfs: don't keep trying to build clusters if we are fragmented
If we are extremely fragmented then we won't be able to create a free_cluster.
So if this happens set last_ptr->fragmented so that all future allcations will
give up trying to create a cluster.  When we unpin extents we will unset
->fragmented if we free up a sufficient amount of space in a block group.
Thanks,

Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-10-21 18:55:39 -07:00
Josef Bacik 4f4db2174d Btrfs: keep track of max_extent_size per space_info
When we are heavily fragmented we can induce a lot of latency trying to make an
allocation happen that is simply not going to happen.  Thankfully we keep track
of our max_extent_size when going through the allocator, so if we get to the
point where we are exiting find_free_extent with ENOSPC then set our
space_info->max_extent_size so we can keep future allocations from having to pay
this cost.  We reset the max_extent_size whenever we release pinned bytes back
into this space info so we can redo all the work.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-10-21 18:55:19 -07:00
Josef Bacik d0bd456074 Btrfs: add fragment=* debug mount option
In tracking down these weird bitmap problems it was helpful to artificially
create an extremely fragmented file system.  These mount options let us either
fragment data or metadata or both.  With these options I could reproduce all
sorts of weird latencies and hangs that occur under extreme fragmentation and
get them fixed.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-10-21 18:51:43 -07:00
Qu Wenruo 51773bec7e btrfs: qgroup: Avoid calling btrfs_free_reserved_data_space in clear_bit_hook
In clear_bit_hook, qgroup reserved data is already handled quite well,
either released by finish_ordered_io or invalidatepage.

So calling btrfs_qgroup_free_data() here is completely meaningless, and
since btrfs_qgroup_free_data() will lock io_tree, so it can't be called
with io_tree lock hold.

This patch will add a new function
btrfs_free_reserved_data_space_noquota() for clear_bit_hook() to cease
the lockdep warning.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-10-21 18:41:09 -07:00
Qu Wenruo 7cf5b97650 btrfs: qgroup: Cleanup old inaccurate facilities
Cleanup the old facilities which use old btrfs_qgroup_reserve() function
call, replace them with the newer version, and remove the "__" prefix in
them.

Also, make btrfs_qgroup_reserve/free() functions private, as they are
now only used inside qgroup codes.

Now, the whole btrfs qgroup is swithed to use the new reserve facilities.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-10-21 18:41:06 -07:00
Qu Wenruo 1ada3a62b5 btrfs: extent-tree: Add new version of btrfs_delalloc_reserve/release_space
Add new version of btrfs_delalloc_reserve_space() and
btrfs_delalloc_release_space() functions, which supports accurate qgroup
reserve.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-10-21 18:41:05 -07:00
Qu Wenruo 4ceff0792d btrfs: extent-tree: Add new version of btrfs_check_data_free_space and btrfs_free_reserved_data_space.
Add new functions __btrfs_check_data_free_space() and
__btrfs_free_reserved_data_space() to work with new accurate qgroup
reserved space framework.

The new function will replace old btrfs_check_data_free_space() and
btrfs_free_reserved_data_space() respectively, but until all the change
is done, let's just use the new name.

Also, export internal use function btrfs_alloc_data_chunk_ondemand(), as
now qgroup reserve requires precious bytes, some operation can't get the
accurate number in advance(like fallocate).
But data space info check and data chunk allocate doesn't need to be
that accurate, and can be called at the beginning.

So export it for later operations.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-10-21 18:41:03 -07:00
Qu Wenruo 55eeaf0578 btrfs: qgroup: Introduce new functions to reserve/free metadata
Introduce new functions btrfs_qgroup_reserve/free_meta() to reserve/free
metadata reserved space.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-10-21 18:37:47 -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 1dd6d7ca9d btrfs: introduce ratelimited variants of message printing functions
Signed-off-by: David Sterba <dsterba@suse.com>
2015-10-08 11:07:56 +02:00
David Sterba 24aa6b41d4 btrfs: introduce ratelimited _in_rcu variants of message printing functions
Signed-off-by: David Sterba <dsterba@suse.com>
2015-10-08 11:07:55 +02:00
David Sterba 08a84e25a8 btrfs: introduce _in_rcu variants of message printing functions
Due to the missing variants there are messages that lack the information
printed by btrfs_info etc helpers.

Signed-off-by: David Sterba <dsterba@suse.com>
2015-10-08 11:07:55 +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 6618a59bfc Btrfs: rename btrfs_sysfs_remove_one to btrfs_sysfs_remove_mounted
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2015-09-29 16:29:58 +02:00
Anand Jain 96f3136e51 Btrfs: rename btrfs_sysfs_add_one to btrfs_sysfs_add_mounted
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2015-09-29 16:29:57 +02:00
Chris Mason 46cd28555f Merge branch 'jeffm-discard-4.3' into for-linus-4.3 2015-08-09 07:35:33 -07:00
Byongho Lee a4027a20c5 Btrfs: remove unused mutex from struct 'btrfs_fs_info'
The code using 'ordered_extent_flush_mutex' mutex has removed by below
commit.
 - 8d875f95da
   btrfs: disable strict file flushes for renames and truncates
But the mutex still lives in struct 'btrfs_fs_info'.

So, this patch removes the mutex from struct 'btrfs_fs_info' and its
initialization code.

Signed-off-by: Byongho Lee <bhlee.kernel@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-08-09 07:34:27 -07:00
Zhaolei 147d256e09 btrfs: Remove unnecessary variants in relocation.c
These arguments are not used in functions, remove them for cleanup
and make kernel stack happy.

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-08-09 07:07:14 -07:00
Zhaolei 868f401ae3 btrfs: Use ref_cnt for set_block_group_ro()
More than one code call set_block_group_ro() and restore rw in fail.

Old code use bool bit to save blockgroup's ro state, it can not
support parallel case(it is confirmd exist in my debug log).

This patch use ref count to store ro state, and rename
set_block_group_ro/set_block_group_rw
to
inc_block_group_ro/dec_block_group_ro.

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-08-09 07:07:12 -07:00
Jeff Mahoney e33e17ee10 btrfs: add missing discards when unpinning extents with -o discard
When we clear the dirty bits in btrfs_delete_unused_bgs for extents
in the empty block group, it results in btrfs_finish_extent_commit being
unable to discard the freed extents.

The block group removal patch added an alternate path to forget extents
other than btrfs_finish_extent_commit.  As a result, any extents that
would be freed when the block group is removed aren't discarded.  In my
test run, with a large copy of mixed sized files followed by removal, it
left nearly 2/3 of extents undiscarded.

To clean up the block groups, we add the removed block group onto a list
that will be discarded after transaction commit.

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 08:15:29 -07:00