Commit graph

1223 commits

Author SHA1 Message Date
Dan Fuhry
cdd1fedf82 btrfs: add support for RENAME_EXCHANGE and RENAME_WHITEOUT
Two new flags, RENAME_EXCHANGE and RENAME_WHITEOUT, provide for new
behavior in the renameat2() syscall. This behavior is primarily used by
overlayfs. This patch adds support for these flags to btrfs, enabling it to
be used as a fully functional upper layer for overlayfs.

RENAME_EXCHANGE support was written by Davide Italiano originally
submitted on 2 April 2015.

Signed-off-by: Davide Italiano <dccitaliano@gmail.com>
Signed-off-by: Dan Fuhry <dfuhry@datto.com>
[ remove unlikely ]
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
2016-05-13 01:59:21 +01:00
Filipe Manana
c4aba95454 Btrfs: pin log earlier when renaming
We were pinning the log right after the first step in the rename operation
(inserting inode ref for the new name in the destination directory)
instead of doing it before. This behaviour was introduced in 2009 for some
reason that was not mentioned neither on the changelog nor any comment,
with the drawback of a small time window where concurrent log writers can
end up logging the new inode reference for the inode we are renaming while
the rename operation is in progress (so that we can end up with a log
containing both the new and old references). As of today there's no reason
to not pin the log before that first step anymore, so just fix this.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
2016-05-13 01:59:19 +01:00
Filipe Manana
3dc9e8f767 Btrfs: unpin log if rename operation fails
If rename operations fail at some point after we pinned the log, we end
up aborting the current transaction but never unpin the log, which leaves
concurrent tasks that are trying to sync the log (as part of an fsync
request from user space) blocked forever and preventing the filesystem
from being unmountable.

Fix this by safely unpinning the log.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
2016-05-13 01:59:18 +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
Al Viro
972b241f84 btrfs: switch to ->iterate_shared()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-09 11:42:19 -04:00
Christoph Hellwig
c8b8e32d70 direct-io: eliminate the offset argument to ->direct_IO
Including blkdev_direct_IO and dax_do_io.  It has to be ki_pos to actually
work, so eliminate the superflous argument.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-01 19:58:39 -04:00
David Sterba
7cd8c7527c btrfs: sink gfp parameter to set_extent_delalloc
Callers pass GFP_NOFS and tests pass GFP_KERNEL, but using NOFS there
does not hurt. No need to pass the flags around.

Signed-off-by: David Sterba <dsterba@suse.com>
2016-04-29 11:01:47 +02:00
David Sterba
91166212e0 btrfs: sink gfp parameter to clear_extent_bits
Callers pass GFP_NOFS and GFP_KERNEL. No need to pass the flags around.

Signed-off-by: David Sterba <dsterba@suse.com>
2016-04-29 11:01:47 +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
Kirill A. Shutemov
09cbfeaf1a mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros
PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time
ago with promise that one day it will be possible to implement page
cache with bigger chunks than PAGE_SIZE.

This promise never materialized.  And unlikely will.

We have many places where PAGE_CACHE_SIZE assumed to be equal to
PAGE_SIZE.  And it's constant source of confusion on whether
PAGE_CACHE_* or PAGE_* constant should be used in a particular case,
especially on the border between fs and mm.

Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much
breakage to be doable.

Let's stop pretending that pages in page cache are special.  They are
not.

The changes are pretty straight-forward:

 - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;

 - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;

 - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN};

 - page_cache_get() -> get_page();

 - page_cache_release() -> put_page();

This patch contains automated changes generated with coccinelle using
script below.  For some reason, coccinelle doesn't patch header files.
I've called spatch for them manually.

The only adjustment after coccinelle is revert of changes to
PAGE_CAHCE_ALIGN definition: we are going to drop it later.

There are few places in the code where coccinelle didn't reach.  I'll
fix them manually in a separate patch.  Comments and documentation also
will be addressed with the separate patch.

virtual patch

@@
expression E;
@@
- E << (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E

@@
expression E;
@@
- E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E

@@
@@
- PAGE_CACHE_SHIFT
+ PAGE_SHIFT

@@
@@
- PAGE_CACHE_SIZE
+ PAGE_SIZE

@@
@@
- PAGE_CACHE_MASK
+ PAGE_MASK

@@
expression E;
@@
- PAGE_CACHE_ALIGN(E)
+ PAGE_ALIGN(E)

@@
expression E;
@@
- page_cache_get(E)
+ get_page(E)

@@
expression E;
@@
- page_cache_release(E)
+ put_page(E)

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-04 10:41:08 -07:00
Filipe Manana
ade770294d Btrfs: fix deadlock between direct IO reads and buffered writes
While running a test with a mix of buffered IO and direct IO against
the same files I hit a deadlock reported by the following trace:

[11642.140352] INFO: task kworker/u32:3:15282 blocked for more than 120 seconds.
[11642.142452]       Not tainted 4.4.0-rc6-btrfs-next-21+ #1
[11642.143982] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[11642.146332] kworker/u32:3   D ffff880230ef7988 [11642.147737] systemd-journald[571]: Sent WATCHDOG=1 notification.
[11642.149771]     0 15282      2 0x00000000
[11642.151205] Workqueue: btrfs-flush_delalloc btrfs_flush_delalloc_helper [btrfs]
[11642.154074]  ffff880230ef7988 0000000000000246 0000000000014ec0 ffff88023ec94ec0
[11642.156722]  ffff880233fe8f80 ffff880230ef8000 ffff88023ec94ec0 7fffffffffffffff
[11642.159205]  0000000000000002 ffffffff8147b7f9 ffff880230ef79a0 ffffffff8147b541
[11642.161403] Call Trace:
[11642.162129]  [<ffffffff8147b7f9>] ? bit_wait+0x2f/0x2f
[11642.163396]  [<ffffffff8147b541>] schedule+0x82/0x9a
[11642.164871]  [<ffffffff8147e7fe>] schedule_timeout+0x43/0x109
[11642.167020]  [<ffffffff8147b7f9>] ? bit_wait+0x2f/0x2f
[11642.167931]  [<ffffffff8108afd1>] ? trace_hardirqs_on_caller+0x17b/0x197
[11642.182320]  [<ffffffff8108affa>] ? trace_hardirqs_on+0xd/0xf
[11642.183762]  [<ffffffff810b079b>] ? timekeeping_get_ns+0xe/0x33
[11642.185308]  [<ffffffff810b0f61>] ? ktime_get+0x41/0x52
[11642.186782]  [<ffffffff8147ac08>] io_schedule_timeout+0xa0/0x102
[11642.188217]  [<ffffffff8147ac08>] ? io_schedule_timeout+0xa0/0x102
[11642.189626]  [<ffffffff8147b814>] bit_wait_io+0x1b/0x39
[11642.190803]  [<ffffffff8147bb21>] __wait_on_bit_lock+0x4c/0x90
[11642.192158]  [<ffffffff8111829f>] __lock_page+0x66/0x68
[11642.193379]  [<ffffffff81082f29>] ? autoremove_wake_function+0x3a/0x3a
[11642.194831]  [<ffffffffa0450ddd>] lock_page+0x31/0x34 [btrfs]
[11642.197068]  [<ffffffffa0454e3b>] extent_write_cache_pages.isra.19.constprop.35+0x1af/0x2f4 [btrfs]
[11642.199188]  [<ffffffffa0455373>] extent_writepages+0x4b/0x5c [btrfs]
[11642.200723]  [<ffffffffa043c913>] ? btrfs_writepage_start_hook+0xce/0xce [btrfs]
[11642.202465]  [<ffffffffa043aa82>] btrfs_writepages+0x28/0x2a [btrfs]
[11642.203836]  [<ffffffff811236bc>] do_writepages+0x23/0x2c
[11642.205624]  [<ffffffff811198c9>] __filemap_fdatawrite_range+0x5a/0x61
[11642.207057]  [<ffffffff81119946>] filemap_fdatawrite_range+0x13/0x15
[11642.208529]  [<ffffffffa044f87e>] btrfs_start_ordered_extent+0xd0/0x1a1 [btrfs]
[11642.210375]  [<ffffffffa0462613>] ? btrfs_scrubparity_helper+0x140/0x33a [btrfs]
[11642.212132]  [<ffffffffa044f974>] btrfs_run_ordered_extent_work+0x25/0x34 [btrfs]
[11642.213837]  [<ffffffffa046262f>] btrfs_scrubparity_helper+0x15c/0x33a [btrfs]
[11642.215457]  [<ffffffffa046293b>] btrfs_flush_delalloc_helper+0xe/0x10 [btrfs]
[11642.217095]  [<ffffffff8106483e>] process_one_work+0x256/0x48b
[11642.218324]  [<ffffffff81064f20>] worker_thread+0x1f5/0x2a7
[11642.219466]  [<ffffffff81064d2b>] ? rescuer_thread+0x289/0x289
[11642.220801]  [<ffffffff8106a500>] kthread+0xd4/0xdc
[11642.222032]  [<ffffffff8106a42c>] ? kthread_parkme+0x24/0x24
[11642.223190]  [<ffffffff8147fdef>] ret_from_fork+0x3f/0x70
[11642.224394]  [<ffffffff8106a42c>] ? kthread_parkme+0x24/0x24
[11642.226295] 2 locks held by kworker/u32:3/15282:
[11642.227273]  #0:  ("%s-%s""btrfs", name){++++.+}, at: [<ffffffff8106474d>] process_one_work+0x165/0x48b
[11642.229412]  #1:  ((&work->normal_work)){+.+.+.}, at: [<ffffffff8106474d>] process_one_work+0x165/0x48b
[11642.231414] INFO: task kworker/u32:8:15289 blocked for more than 120 seconds.
[11642.232872]       Not tainted 4.4.0-rc6-btrfs-next-21+ #1
[11642.234109] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[11642.235776] kworker/u32:8   D ffff88020de5f848     0 15289      2 0x00000000
[11642.237412] Workqueue: writeback wb_workfn (flush-btrfs-481)
[11642.238670]  ffff88020de5f848 0000000000000246 0000000000014ec0 ffff88023ed54ec0
[11642.240475]  ffff88021b1ece40 ffff88020de60000 ffff88023ed54ec0 7fffffffffffffff
[11642.242154]  0000000000000002 ffffffff8147b7f9 ffff88020de5f860 ffffffff8147b541
[11642.243715] Call Trace:
[11642.244390]  [<ffffffff8147b7f9>] ? bit_wait+0x2f/0x2f
[11642.245432]  [<ffffffff8147b541>] schedule+0x82/0x9a
[11642.246392]  [<ffffffff8147e7fe>] schedule_timeout+0x43/0x109
[11642.247479]  [<ffffffff8147b7f9>] ? bit_wait+0x2f/0x2f
[11642.248551]  [<ffffffff8108afd1>] ? trace_hardirqs_on_caller+0x17b/0x197
[11642.249968]  [<ffffffff8108affa>] ? trace_hardirqs_on+0xd/0xf
[11642.251043]  [<ffffffff810b079b>] ? timekeeping_get_ns+0xe/0x33
[11642.252202]  [<ffffffff810b0f61>] ? ktime_get+0x41/0x52
[11642.253210]  [<ffffffff8147ac08>] io_schedule_timeout+0xa0/0x102
[11642.254307]  [<ffffffff8147ac08>] ? io_schedule_timeout+0xa0/0x102
[11642.256118]  [<ffffffff8147b814>] bit_wait_io+0x1b/0x39
[11642.257131]  [<ffffffff8147bb21>] __wait_on_bit_lock+0x4c/0x90
[11642.258200]  [<ffffffff8111829f>] __lock_page+0x66/0x68
[11642.259168]  [<ffffffff81082f29>] ? autoremove_wake_function+0x3a/0x3a
[11642.260516]  [<ffffffffa0450ddd>] lock_page+0x31/0x34 [btrfs]
[11642.261841]  [<ffffffffa0454e3b>] extent_write_cache_pages.isra.19.constprop.35+0x1af/0x2f4 [btrfs]
[11642.263531]  [<ffffffffa0455373>] extent_writepages+0x4b/0x5c [btrfs]
[11642.264747]  [<ffffffffa043c913>] ? btrfs_writepage_start_hook+0xce/0xce [btrfs]
[11642.266148]  [<ffffffffa043aa82>] btrfs_writepages+0x28/0x2a [btrfs]
[11642.267264]  [<ffffffff811236bc>] do_writepages+0x23/0x2c
[11642.268280]  [<ffffffff81192a2b>] __writeback_single_inode+0xda/0x5ba
[11642.269407]  [<ffffffff811939f0>] writeback_sb_inodes+0x27b/0x43d
[11642.270476]  [<ffffffff81193c28>] __writeback_inodes_wb+0x76/0xae
[11642.271547]  [<ffffffff81193ea6>] wb_writeback+0x19e/0x41c
[11642.272588]  [<ffffffff81194821>] wb_workfn+0x201/0x341
[11642.273523]  [<ffffffff81194821>] ? wb_workfn+0x201/0x341
[11642.274479]  [<ffffffff8106483e>] process_one_work+0x256/0x48b
[11642.275497]  [<ffffffff81064f20>] worker_thread+0x1f5/0x2a7
[11642.276518]  [<ffffffff81064d2b>] ? rescuer_thread+0x289/0x289
[11642.277520]  [<ffffffff81064d2b>] ? rescuer_thread+0x289/0x289
[11642.278517]  [<ffffffff8106a500>] kthread+0xd4/0xdc
[11642.279371]  [<ffffffff8106a42c>] ? kthread_parkme+0x24/0x24
[11642.280468]  [<ffffffff8147fdef>] ret_from_fork+0x3f/0x70
[11642.281607]  [<ffffffff8106a42c>] ? kthread_parkme+0x24/0x24
[11642.282604] 3 locks held by kworker/u32:8/15289:
[11642.283423]  #0:  ("writeback"){++++.+}, at: [<ffffffff8106474d>] process_one_work+0x165/0x48b
[11642.285629]  #1:  ((&(&wb->dwork)->work)){+.+.+.}, at: [<ffffffff8106474d>] process_one_work+0x165/0x48b
[11642.287538]  #2:  (&type->s_umount_key#37){+++++.}, at: [<ffffffff81171217>] trylock_super+0x1b/0x4b
[11642.289423] INFO: task fdm-stress:26848 blocked for more than 120 seconds.
[11642.290547]       Not tainted 4.4.0-rc6-btrfs-next-21+ #1
[11642.291453] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[11642.292864] fdm-stress      D ffff88022c107c20     0 26848  26591 0x00000000
[11642.294118]  ffff88022c107c20 000000038108affa 0000000000014ec0 ffff88023ed54ec0
[11642.295602]  ffff88013ab1ca40 ffff88022c108000 ffff8800b2fc19d0 00000000000e0fff
[11642.297098]  ffff8800b2fc19b0 ffff88022c107c88 ffff88022c107c38 ffffffff8147b541
[11642.298433] Call Trace:
[11642.298896]  [<ffffffff8147b541>] schedule+0x82/0x9a
[11642.299738]  [<ffffffffa045225d>] lock_extent_bits+0xfe/0x1a3 [btrfs]
[11642.300833]  [<ffffffff81082eef>] ? add_wait_queue_exclusive+0x44/0x44
[11642.301943]  [<ffffffffa0447516>] lock_and_cleanup_extent_if_need+0x68/0x18e [btrfs]
[11642.303270]  [<ffffffffa04485ba>] __btrfs_buffered_write+0x238/0x4c1 [btrfs]
[11642.304552]  [<ffffffffa044b50a>] ? btrfs_file_write_iter+0x17c/0x408 [btrfs]
[11642.305782]  [<ffffffffa044b682>] btrfs_file_write_iter+0x2f4/0x408 [btrfs]
[11642.306878]  [<ffffffff8116e298>] __vfs_write+0x7c/0xa5
[11642.307729]  [<ffffffff8116e7d1>] vfs_write+0x9d/0xe8
[11642.308602]  [<ffffffff8116efbb>] SyS_write+0x50/0x7e
[11642.309410]  [<ffffffff8147fa97>] entry_SYSCALL_64_fastpath+0x12/0x6b
[11642.310403] 3 locks held by fdm-stress/26848:
[11642.311108]  #0:  (&f->f_pos_lock){+.+.+.}, at: [<ffffffff811877e8>] __fdget_pos+0x3a/0x40
[11642.312578]  #1:  (sb_writers#11){.+.+.+}, at: [<ffffffff811706ee>] __sb_start_write+0x5f/0xb0
[11642.314170]  #2:  (&sb->s_type->i_mutex_key#15){+.+.+.}, at: [<ffffffffa044b401>] btrfs_file_write_iter+0x73/0x408 [btrfs]
[11642.316796] INFO: task fdm-stress:26849 blocked for more than 120 seconds.
[11642.317842]       Not tainted 4.4.0-rc6-btrfs-next-21+ #1
[11642.318691] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[11642.319959] fdm-stress      D ffff8801964ffa68     0 26849  26591 0x00000000
[11642.321312]  ffff8801964ffa68 00ff8801e9975f80 0000000000014ec0 ffff88023ed94ec0
[11642.322555]  ffff8800b00b4840 ffff880196500000 ffff8801e9975f20 0000000000000002
[11642.323715]  ffff8801e9975f18 ffff8800b00b4840 ffff8801964ffa80 ffffffff8147b541
[11642.325096] Call Trace:
[11642.325532]  [<ffffffff8147b541>] schedule+0x82/0x9a
[11642.326303]  [<ffffffff8147e7fe>] schedule_timeout+0x43/0x109
[11642.327180]  [<ffffffff8108ae40>] ? mark_held_locks+0x5e/0x74
[11642.328114]  [<ffffffff8147f30e>] ? _raw_spin_unlock_irq+0x2c/0x4a
[11642.329051]  [<ffffffff8108afd1>] ? trace_hardirqs_on_caller+0x17b/0x197
[11642.330053]  [<ffffffff8147bceb>] __wait_for_common+0x109/0x147
[11642.330952]  [<ffffffff8147bceb>] ? __wait_for_common+0x109/0x147
[11642.331869]  [<ffffffff8147e7bb>] ? usleep_range+0x4a/0x4a
[11642.332925]  [<ffffffff81074075>] ? wake_up_q+0x47/0x47
[11642.333736]  [<ffffffff8147bd4d>] wait_for_completion+0x24/0x26
[11642.334672]  [<ffffffffa044f5ce>] btrfs_wait_ordered_extents+0x1c8/0x217 [btrfs]
[11642.335858]  [<ffffffffa0465b5a>] btrfs_mksubvol+0x224/0x45d [btrfs]
[11642.336854]  [<ffffffff81082eef>] ? add_wait_queue_exclusive+0x44/0x44
[11642.337820]  [<ffffffffa0465edb>] btrfs_ioctl_snap_create_transid+0x148/0x17a [btrfs]
[11642.339026]  [<ffffffffa046603b>] btrfs_ioctl_snap_create_v2+0xc7/0x110 [btrfs]
[11642.340214]  [<ffffffffa0468582>] btrfs_ioctl+0x590/0x27bd [btrfs]
[11642.341123]  [<ffffffff8147dc00>] ? mutex_unlock+0xe/0x10
[11642.341934]  [<ffffffffa00fa6e9>] ? ext4_file_write_iter+0x2a3/0x36f [ext4]
[11642.342936]  [<ffffffff8108895d>] ? __lock_is_held+0x3c/0x57
[11642.343772]  [<ffffffff81186a1d>] ? rcu_read_unlock+0x3e/0x5d
[11642.344673]  [<ffffffff8117dc95>] do_vfs_ioctl+0x458/0x4dc
[11642.346024]  [<ffffffff81186bbe>] ? __fget_light+0x62/0x71
[11642.346873]  [<ffffffff8117dd70>] SyS_ioctl+0x57/0x79
[11642.347720]  [<ffffffff8147fa97>] entry_SYSCALL_64_fastpath+0x12/0x6b
[11642.350222] 4 locks held by fdm-stress/26849:
[11642.350898]  #0:  (sb_writers#11){.+.+.+}, at: [<ffffffff811706ee>] __sb_start_write+0x5f/0xb0
[11642.352375]  #1:  (&type->i_mutex_dir_key#4/1){+.+.+.}, at: [<ffffffffa0465981>] btrfs_mksubvol+0x4b/0x45d [btrfs]
[11642.354072]  #2:  (&fs_info->subvol_sem){++++..}, at: [<ffffffffa0465a2a>] btrfs_mksubvol+0xf4/0x45d [btrfs]
[11642.355647]  #3:  (&root->ordered_extent_mutex){+.+...}, at: [<ffffffffa044f456>] btrfs_wait_ordered_extents+0x50/0x217 [btrfs]
[11642.357516] INFO: task fdm-stress:26850 blocked for more than 120 seconds.
[11642.358508]       Not tainted 4.4.0-rc6-btrfs-next-21+ #1
[11642.359376] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[11642.368625] fdm-stress      D ffff88021f167688     0 26850  26591 0x00000000
[11642.369716]  ffff88021f167688 0000000000000001 0000000000014ec0 ffff88023edd4ec0
[11642.370950]  ffff880128a98680 ffff88021f168000 ffff88023edd4ec0 7fffffffffffffff
[11642.372210]  0000000000000002 ffffffff8147b7f9 ffff88021f1676a0 ffffffff8147b541
[11642.373430] Call Trace:
[11642.373853]  [<ffffffff8147b7f9>] ? bit_wait+0x2f/0x2f
[11642.374623]  [<ffffffff8147b541>] schedule+0x82/0x9a
[11642.375948]  [<ffffffff8147e7fe>] schedule_timeout+0x43/0x109
[11642.376862]  [<ffffffff8147b7f9>] ? bit_wait+0x2f/0x2f
[11642.377637]  [<ffffffff8108afd1>] ? trace_hardirqs_on_caller+0x17b/0x197
[11642.378610]  [<ffffffff8108affa>] ? trace_hardirqs_on+0xd/0xf
[11642.379457]  [<ffffffff810b079b>] ? timekeeping_get_ns+0xe/0x33
[11642.380366]  [<ffffffff810b0f61>] ? ktime_get+0x41/0x52
[11642.381353]  [<ffffffff8147ac08>] io_schedule_timeout+0xa0/0x102
[11642.382255]  [<ffffffff8147ac08>] ? io_schedule_timeout+0xa0/0x102
[11642.383162]  [<ffffffff8147b814>] bit_wait_io+0x1b/0x39
[11642.383945]  [<ffffffff8147bb21>] __wait_on_bit_lock+0x4c/0x90
[11642.384875]  [<ffffffff8111829f>] __lock_page+0x66/0x68
[11642.385749]  [<ffffffff81082f29>] ? autoremove_wake_function+0x3a/0x3a
[11642.386721]  [<ffffffffa0450ddd>] lock_page+0x31/0x34 [btrfs]
[11642.387596]  [<ffffffffa0454e3b>] extent_write_cache_pages.isra.19.constprop.35+0x1af/0x2f4 [btrfs]
[11642.389030]  [<ffffffffa0455373>] extent_writepages+0x4b/0x5c [btrfs]
[11642.389973]  [<ffffffff810a25ad>] ? rcu_read_lock_sched_held+0x61/0x69
[11642.390939]  [<ffffffffa043c913>] ? btrfs_writepage_start_hook+0xce/0xce [btrfs]
[11642.392271]  [<ffffffffa0451c32>] ? __clear_extent_bit+0x26e/0x2c0 [btrfs]
[11642.393305]  [<ffffffffa043aa82>] btrfs_writepages+0x28/0x2a [btrfs]
[11642.394239]  [<ffffffff811236bc>] do_writepages+0x23/0x2c
[11642.395045]  [<ffffffff811198c9>] __filemap_fdatawrite_range+0x5a/0x61
[11642.395991]  [<ffffffff81119946>] filemap_fdatawrite_range+0x13/0x15
[11642.397144]  [<ffffffffa044f87e>] btrfs_start_ordered_extent+0xd0/0x1a1 [btrfs]
[11642.398392]  [<ffffffffa0452094>] ? clear_extent_bit+0x17/0x19 [btrfs]
[11642.399363]  [<ffffffffa0445945>] btrfs_get_blocks_direct+0x12b/0x61c [btrfs]
[11642.400445]  [<ffffffff8119f7a1>] ? dio_bio_add_page+0x3d/0x54
[11642.401309]  [<ffffffff8119fa93>] ? submit_page_section+0x7b/0x111
[11642.402213]  [<ffffffff811a0258>] do_blockdev_direct_IO+0x685/0xc24
[11642.403139]  [<ffffffffa044581a>] ? btrfs_page_exists_in_range+0x1a1/0x1a1 [btrfs]
[11642.404360]  [<ffffffffa043d267>] ? btrfs_get_extent_fiemap+0x1c0/0x1c0 [btrfs]
[11642.406187]  [<ffffffff811a0828>] __blockdev_direct_IO+0x31/0x33
[11642.407070]  [<ffffffff811a0828>] ? __blockdev_direct_IO+0x31/0x33
[11642.407990]  [<ffffffffa043d267>] ? btrfs_get_extent_fiemap+0x1c0/0x1c0 [btrfs]
[11642.409192]  [<ffffffffa043b4ca>] btrfs_direct_IO+0x1c7/0x27e [btrfs]
[11642.410146]  [<ffffffffa043d267>] ? btrfs_get_extent_fiemap+0x1c0/0x1c0 [btrfs]
[11642.411291]  [<ffffffff81119a2c>] generic_file_read_iter+0x89/0x4e1
[11642.412263]  [<ffffffff8108ac05>] ? mark_lock+0x24/0x201
[11642.413057]  [<ffffffff8116e1f8>] __vfs_read+0x79/0x9d
[11642.413897]  [<ffffffff8116e6f1>] vfs_read+0x8f/0xd2
[11642.414708]  [<ffffffff8116ef3d>] SyS_read+0x50/0x7e
[11642.415573]  [<ffffffff8147fa97>] entry_SYSCALL_64_fastpath+0x12/0x6b
[11642.416572] 1 lock held by fdm-stress/26850:
[11642.417345]  #0:  (&f->f_pos_lock){+.+.+.}, at: [<ffffffff811877e8>] __fdget_pos+0x3a/0x40
[11642.418703] INFO: task fdm-stress:26851 blocked for more than 120 seconds.
[11642.419698]       Not tainted 4.4.0-rc6-btrfs-next-21+ #1
[11642.420612] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[11642.421807] fdm-stress      D ffff880196483d28     0 26851  26591 0x00000000
[11642.422878]  ffff880196483d28 00ff8801c8f60740 0000000000014ec0 ffff88023ed94ec0
[11642.424149]  ffff8801c8f60740 ffff880196484000 0000000000000246 ffff8801c8f60740
[11642.425374]  ffff8801bb711840 ffff8801bb711878 ffff880196483d40 ffffffff8147b541
[11642.426591] Call Trace:
[11642.427013]  [<ffffffff8147b541>] schedule+0x82/0x9a
[11642.427856]  [<ffffffff8147b6d5>] schedule_preempt_disabled+0x18/0x24
[11642.428852]  [<ffffffff8147c23a>] mutex_lock_nested+0x1d7/0x3b4
[11642.429743]  [<ffffffffa044f456>] ? btrfs_wait_ordered_extents+0x50/0x217 [btrfs]
[11642.430911]  [<ffffffffa044f456>] btrfs_wait_ordered_extents+0x50/0x217 [btrfs]
[11642.432102]  [<ffffffffa044f674>] ? btrfs_wait_ordered_roots+0x57/0x191 [btrfs]
[11642.433259]  [<ffffffffa044f456>] ? btrfs_wait_ordered_extents+0x50/0x217 [btrfs]
[11642.434431]  [<ffffffffa044f6ea>] btrfs_wait_ordered_roots+0xcd/0x191 [btrfs]
[11642.436079]  [<ffffffffa0410cab>] btrfs_sync_fs+0xe0/0x1ad [btrfs]
[11642.437009]  [<ffffffff81197900>] ? SyS_tee+0x23c/0x23c
[11642.437860]  [<ffffffff81197920>] sync_fs_one_sb+0x20/0x22
[11642.438723]  [<ffffffff81171435>] iterate_supers+0x75/0xc2
[11642.439597]  [<ffffffff81197d00>] sys_sync+0x52/0x80
[11642.440454]  [<ffffffff8147fa97>] entry_SYSCALL_64_fastpath+0x12/0x6b
[11642.441533] 3 locks held by fdm-stress/26851:
[11642.442370]  #0:  (&type->s_umount_key#37){+++++.}, at: [<ffffffff8117141f>] iterate_supers+0x5f/0xc2
[11642.444043]  #1:  (&fs_info->ordered_operations_mutex){+.+...}, at: [<ffffffffa044f661>] btrfs_wait_ordered_roots+0x44/0x191 [btrfs]
[11642.446010]  #2:  (&root->ordered_extent_mutex){+.+...}, at: [<ffffffffa044f456>] btrfs_wait_ordered_extents+0x50/0x217 [btrfs]

This happened because under specific timings the path for direct IO reads
can deadlock with concurrent buffered writes. The diagram below shows how
this happens for an example file that has the following layout:

     [  extent A  ]  [  extent B  ]  [ ....
     0K              4K              8K

     CPU 1                                               CPU 2                             CPU 3

DIO read against range
 [0K, 8K[ starts

btrfs_direct_IO()
  --> calls btrfs_get_blocks_direct()
      which finds the extent map for the
      extent A and leaves the range
      [0K, 4K[ locked in the inode's
      io tree

                                                   buffered write against
                                                   range [4K, 8K[ starts

                                                   __btrfs_buffered_write()
                                                     --> dirties page at 4K

                                                                                     a user space
                                                                                     task calls sync
                                                                                     for e.g or
                                                                                     writepages() is
                                                                                     invoked by mm

                                                                                     writepages()
                                                                                       run_delalloc_range()
                                                                                         cow_file_range()
                                                                                           --> ordered extent X
                                                                                               for the buffered
                                                                                               write is created
                                                                                               and
                                                                                               writeback starts

  --> calls btrfs_get_blocks_direct()
      again, without submitting first
      a bio for reading extent A, and
      finds the extent map for extent B

  --> calls lock_extent_direct()

      --> locks range [4K, 8K[
      --> finds ordered extent X
          covering range [4K, 8K[
      --> unlocks range [4K, 8K[

                                                  buffered write against
                                                  range [0K, 8K[ starts

                                                  __btrfs_buffered_write()
                                                    prepare_pages()
                                                      --> locks pages with
                                                          offsets 0 and 4K
                                                    lock_and_cleanup_extent_if_need()
                                                      --> blocks attempting to
                                                          lock range [0K, 8K[ in
                                                          the inode's io tree,
                                                          because the range [0, 4K[
                                                          is already locked by the
                                                          direct IO task at CPU 1

      --> calls
          btrfs_start_ordered_extent(oe X)

          btrfs_start_ordered_extent(oe X)

            --> At this point writeback for ordered
                extent X has not finished yet

            filemap_fdatawrite_range()
              btrfs_writepages()
                extent_writepages()
                  extent_write_cache_pages()
                    --> finds page with offset 0
                        with the writeback tag
                        (and not dirty)
                    --> tries to lock it
                         --> deadlock, task at CPU 2
                             has the page locked and
                             is blocked on the io range
                             [0, 4K[ that was locked
                             earlier by this task

So fix this by falling back to a buffered read in the direct IO read path
when an ordered extent for a buffered write is found.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Chris Mason <clm@fb.com>
2016-03-01 08:23:37 -08:00
Chris Mason
c05c5ee5ea Btrfs patchsets for 4.6
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Merge tag 'for-chris' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux into for-linus-4.6

Btrfs patchsets for 4.6
2016-03-01 08:13:56 -08:00
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
e9ddd77a31 Merge branch 'foreign/josef/space-updates' into for-chris-4.6 2016-02-26 15:38:31 +01:00
David Sterba
e22b3d1fbe Merge branch 'dev/gfp-flags' into for-chris-4.6 2016-02-26 15:38:28 +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
Linus Torvalds
ce6b71432d Merge branch 'for-linus-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs
Pull btrfs fix from Chris Mason:
 "My for-linus-4.5 branch has a btrfs DIO error passing fix.

  I know how much you love DIO, so I'm going to suggest against reading
  it.  We'll follow up with a patch to drop the error arg from
  dio_end_io in the next merge window."

* 'for-linus-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  Btrfs: fix direct IO requests not reporting IO error to user space
2016-02-19 13:40:42 -08:00
Kinglong Mee
5598e9005a btrfs: drop null testing before destroy functions
Cleanup.

kmem_cache_destroy has support NULL argument checking,
so drop the double null testing before calling it.

Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2016-02-18 11:46:03 +01:00
Deepa Dinamani
04b285f35e btrfs: Replace CURRENT_TIME by current_fs_time()
CURRENT_TIME macro is not appropriate for filesystems as it
doesn't use the right granularity for filesystem timestamps.
Use current_fs_time() instead.

Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Cc: Chris Mason <clm@fb.com>
Cc: Josef Bacik <jbacik@fb.com>
Cc: linux-btrfs@vger.kernel.org
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2016-02-18 11:46:03 +01:00
Josef Bacik
dc95f7bfc5 Btrfs: fix truncate_space_check
truncate_space_check is using btrfs_csum_bytes_to_leaves() but forgetting to
multiply by nodesize so we get an actual byte count.  We need a tracepoint here
so that we have the matching reserve for the release that will come later.  Also
add a comment to make clear what the intent of truncate_space_check is.

Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2016-02-18 11:22:24 +01:00
Filipe Manana
1636d1d77e Btrfs: fix direct IO requests not reporting IO error to user space
If a bio for a direct IO request fails, we were not setting the error in
the parent bio (the main DIO bio), making us not return the error to
user space in btrfs_direct_IO(), that is, it made __blockdev_direct_IO()
return the number of bytes issued for IO and not the error a bio created
and submitted by btrfs_submit_direct() got from the block layer.
This essentially happens because when we call:

   dio_end_io(dio_bio, bio->bi_error);

It does not set dio_bio->bi_error to the value of the second argument.
So just add this missing assignment in endio callbacks, just as we do in
the error path at btrfs_submit_direct() when we fail to clone the dio bio
or allocate its private object. This follows the convention of what is
done with other similar APIs such as bio_endio() where the caller is
responsible for setting the bi_error field in the bio it passes as an
argument to bio_endio().

This was detected by the new generic test cases in xfstests: 271, 272,
276 and 278. Which essentially setup a dm error target, then load the
error table, do a direct IO write and unload the error table. They
expect the write to fail with -EIO, which was not getting reported
when testing against btrfs.

Cc: stable@vger.kernel.org  # 4.3+
Fixes: 4246a0b63b ("block: add a bi_error field to struct bio")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
2016-02-16 03:41:26 +00:00
Linus Torvalds
27c9d772e5 Merge branch 'for-linus-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs
Pull btrfs fixes from Chris Mason:
 "This has a few fixes from Filipe, along with a readdir fix from Dave
  that we've been testing for some time"

* 'for-linus-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  btrfs: properly set the termination value of ctx->pos in readdir
  Btrfs: fix hang on extent buffer lock caused by the inode_paths ioctl
  Btrfs: remove no longer used function extent_read_full_page_nolock()
  Btrfs: fix page reading in extent_same ioctl leading to csum errors
  Btrfs: fix invalid page accesses in extent_same (dedup) ioctl
2016-02-12 09:21:28 -08:00
David Sterba
bc4ef7592f btrfs: properly set the termination value of ctx->pos in readdir
The value of ctx->pos in the last readdir call is supposed to be set to
INT_MAX due to 32bit compatibility, unless 'pos' is intentially set to a
larger value, then it's LLONG_MAX.

There's a report from PaX SIZE_OVERFLOW plugin that "ctx->pos++"
overflows (https://forums.grsecurity.net/viewtopic.php?f=1&t=4284), on a
64bit arch, where the value is 0x7fffffffffffffff ie. LLONG_MAX before
the increment.

We can get to that situation like that:

* emit all regular readdir entries
* still in the same call to readdir, bump the last pos to INT_MAX
* next call to readdir will not emit any entries, but will reach the
  bump code again, finds pos to be INT_MAX and sets it to LLONG_MAX

Normally this is not a problem, but if we call readdir again, we'll find
'pos' set to LLONG_MAX and the unconditional increment will overflow.

The report from Victor at
(http://thread.gmane.org/gmane.comp.file-systems.btrfs/49500) with debugging
print shows that pattern:

 Overflow: e
 Overflow: 7fffffff
 Overflow: 7fffffffffffffff
 PAX: size overflow detected in function btrfs_real_readdir
   fs/btrfs/inode.c:5760 cicus.935_282 max, count: 9, decl: pos; num: 0;
   context: dir_context;
 CPU: 0 PID: 2630 Comm: polkitd Not tainted 4.2.3-grsec #1
 Hardware name: Gigabyte Technology Co., Ltd. H81ND2H/H81ND2H, BIOS F3 08/11/2015
  ffffffff81901608 0000000000000000 ffffffff819015e6 ffffc90004973d48
  ffffffff81742f0f 0000000000000007 ffffffff81901608 ffffc90004973d78
  ffffffff811cb706 0000000000000000 ffff8800d47359e0 ffffc90004973ed8
 Call Trace:
  [<ffffffff81742f0f>] dump_stack+0x4c/0x7f
  [<ffffffff811cb706>] report_size_overflow+0x36/0x40
  [<ffffffff812ef0bc>] btrfs_real_readdir+0x69c/0x6d0
  [<ffffffff811dafc8>] iterate_dir+0xa8/0x150
  [<ffffffff811e6d8d>] ? __fget_light+0x2d/0x70
  [<ffffffff811dba3a>] SyS_getdents+0xba/0x1c0
 Overflow: 1a
  [<ffffffff811db070>] ? iterate_dir+0x150/0x150
  [<ffffffff81749b69>] entry_SYSCALL_64_fastpath+0x12/0x83

The jump from 7fffffff to 7fffffffffffffff happens when new dir entries
are not yet synced and are processed from the delayed list. Then the code
could go to the bump section again even though it might not emit any new
dir entries from the delayed list.

The fix avoids entering the "bump" section again once we've finished
emitting the entries, both for synced and delayed entries.

References: https://forums.grsecurity.net/viewtopic.php?f=1&t=4284
Reported-by: Victor <services@swwu.com>
CC: stable@vger.kernel.org
Signed-off-by: David Sterba <dsterba@suse.com>
Tested-by: Holger Hoffstätte <holger.hoffstaette@googlemail.com>
Signed-off-by: Chris Mason <clm@fb.com>
2016-02-11 07:01:59 -08:00
David Sterba
49e350a491 btrfs: readdir: use GFP_KERNEL
Readdir is initiated from userspace and is not on the critical
writeback path, we don't need to use GFP_NOFS for allocations.

Signed-off-by: David Sterba <dsterba@suse.com>
2016-02-11 15:19:39 +01:00
Chandan Rajendra
27772b68f6 Btrfs: Clean pte corresponding to page straddling i_size
When extending a file by either "truncate up" or by writing beyond i_size, the
page which had i_size needs to be marked "read only" so that future writes to
the page via mmap interface causes btrfs_page_mkwrite() to be invoked. If not,
a write performed after extending the file via the mmap interface will find
the page to be writaeable and continue writing to the page without invoking
btrfs_page_mkwrite() i.e. we end up writing to a file without reserving disk
space.

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
5a2834f808 Btrfs: Fix block size returned to user space
btrfs_getattr() returns PAGE_CACHE_SIZE as the block size. Since
generic_fillattr() already does the right thing (by obtaining block size
from inode->i_blkbits), just remove the statement from btrfs_getattr.

Reviewed-by: Josef Bacik <jbacik@fb.com>
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
0c29ba993e Btrfs: Limit inline extents to root->sectorsize
cow_file_range_inline() limits the size of an inline extent to
PAGE_CACHE_SIZE. This breaks in subpagesize-blocksize scenarios. Fix this by
comparing against root->sectorsize.

Reviewed-by: Josef Bacik <jbacik@fb.com>
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
5f4dc8fc83 Btrfs: btrfs_submit_direct_hook: Handle map_length < bio vector length
In subpagesize-blocksize scenario, map_length can be less than the length of a
bio vector. Such a condition may cause btrfs_submit_direct_hook() to submit a
zero length bio. Fix this by comparing map_length against block size rather
than with bv_len.

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
dbfdb6d1b3 Btrfs: Search for all ordered extents that could span across a page
In subpagesize-blocksize scenario it is not sufficient to search using the
first byte of the page to make sure that there are no ordered extents
present across the page. Fix this.

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
d0b7da88f6 Btrfs: btrfs_page_mkwrite: Reserve space in sectorsized units
In subpagesize-blocksize scenario, if i_size occurs in a block which is not
the last block in the page, then the space to be reserved should be calculated
appropriately.

Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
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
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
2dabb32484 Btrfs: Direct I/O read: Work on sectorsized blocks
The direct I/O read's endio and corresponding repair functions work on
page sized blocks. This commit adds the ability for direct I/O read to work on
subpagesized blocks.

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
d3f71ae711 Merge branch 'for-linus-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs
Pull btrfs fixes from Chris Mason:
 "Dave had a small collection of fixes to the new free space tree code,
  one of which was keeping our sysfs files more up to date with feature
  bits as different things get enabled (lzo, raid5/6, etc).

  I should have kept the sysfs stuff for rc3, since we always manage to
  trip over something.  This time it was GFP_KERNEL from somewhere that
  is NOFS only.  Instead of rebasing it out I've put a revert in, and
  we'll fix it properly for rc3.

  Otherwise, Filipe fixed a btrfs DIO race and Qu Wenruo fixed up a
  use-after-free in our tracepoints that Dave Jones reported"

* 'for-linus-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  Revert "btrfs: synchronize incompat feature bits with sysfs files"
  btrfs: don't use GFP_HIGHMEM for free-space-tree bitmap kzalloc
  btrfs: sysfs: check initialization state before updating features
  Revert "btrfs: clear PF_NOFREEZE in cleaner_kthread()"
  btrfs: async-thread: Fix a use-after-free error for trace
  Btrfs: fix race between fsync and lockless direct IO writes
  btrfs: add free space tree to the cow-only list
  btrfs: add free space tree to lockdep classes
  btrfs: tweak free space tree bitmap allocation
  btrfs: tests: switch to GFP_KERNEL
  btrfs: synchronize incompat feature bits with sysfs files
  btrfs: sysfs: introduce helper for syncing bits with sysfs files
  btrfs: sysfs: add free-space-tree bit attribute
  btrfs: sysfs: fix typo in compat_ro attribute definition
2016-01-29 15:46:49 -08:00
Filipe Manana
de0ee0edb2 Btrfs: fix race between fsync and lockless direct IO writes
An fsync, using the fast path, can race with a concurrent lockless direct
IO write and end up logging a file extent item that points to an extent
that wasn't written to yet. This is because the fast fsync path collects
ordered extents into a local list and then collects all the new extent
maps to log file extent items based on them, while the direct IO write
path creates the new extent map before it creates the corresponding
ordered extent (and submitting the respective bio(s)).

So fix this by making the direct IO write path create ordered extents
before the extent maps and make the fast fsync path collect any new
ordered extents after it collects the extent maps.
Note that making the fsync handler call inode_dio_wait() (after acquiring
the inode's i_mutex) would not work and lead to a deadlock when doing
AIO, as through AIO we end up in a path where the fsync handler is called
(through dio_aio_complete_work() -> dio_complete() -> vfs_fsync_range())
before the inode's dio counter is decremented (inode_dio_wait() waits
for this counter to have a value of zero).

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
2016-01-25 16:50:26 -08:00
Al Viro
5955102c99 wrappers for ->i_mutex access
parallel to mutex_{lock,unlock,trylock,is_locked,lock_nested},
inode_foo(inode) being mutex_foo(&inode->i_mutex).

Please, use those for access to ->i_mutex; over the coming cycle
->i_mutex will become rwsem, with ->lookup() done with it held
only shared.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-01-22 18:04:28 -05:00
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
Vladimir Davydov
5d097056c9 kmemcg: account certain kmem allocations to memcg
Mark those kmem allocations that are known to be easily triggered from
userspace as __GFP_ACCOUNT/SLAB_ACCOUNT, which makes them accounted to
memcg.  For the list, see below:

 - threadinfo
 - task_struct
 - task_delay_info
 - pid
 - cred
 - mm_struct
 - vm_area_struct and vm_region (nommu)
 - anon_vma and anon_vma_chain
 - signal_struct
 - sighand_struct
 - fs_struct
 - files_struct
 - fdtable and fdtable->full_fds_bits
 - dentry and external_name
 - inode for all filesystems. This is the most tedious part, because
   most filesystems overwrite the alloc_inode method.

The list is far from complete, so feel free to add more objects.
Nevertheless, it should be close to "account everything" approach and
keep most workloads within bounds.  Malevolent users will be able to
breach the limit, but this was possible even with the former "account
everything" approach (simply because it did not account everything in
fact).

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Greg Thelen <gthelen@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-14 16:00:49 -08:00
Linus Torvalds
ddf1d6238d Merge branch 'work.xattr' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs xattr updates from Al Viro:
 "Andreas' xattr cleanup series.

  It's a followup to his xattr work that went in last cycle; -0.5KLoC"

* 'work.xattr' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  xattr handlers: Simplify list operation
  ocfs2: Replace list xattr handler operations
  nfs: Move call to security_inode_listsecurity into nfs_listxattr
  xfs: Change how listxattr generates synthetic attributes
  tmpfs: listxattr should include POSIX ACL xattrs
  tmpfs: Use xattr handler infrastructure
  btrfs: Use xattr handler infrastructure
  vfs: Distinguish between full xattr names and proper prefixes
  posix acls: Remove duplicate xattr name definitions
  gfs2: Remove gfs2_xattr_acl_chmod
  vfs: Remove vfs_xattr_cmp
2016-01-11 13:32:10 -08:00
Chris Mason
988f1f576d Merge branch 'for-chris-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/fdmanana/linux into for-linus-4.5
Signed-off-by: Chris Mason <clm@fb.com>
2016-01-11 08:39:28 -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
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
David Sterba
20e5506baf btrfs: constify remaining structs with function pointers
* struct extent_io_ops
* struct btrfs_free_space_op

Signed-off-by: David Sterba <dsterba@suse.com>
2016-01-07 15:01:14 +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
David Sterba
7928d672ff btrfs: cleanup, remove stray return statements
Signed-off-by: David Sterba <dsterba@suse.com>
2016-01-07 14:30:52 +01:00