1. 11 6月, 2015 13 次提交
  2. 10 6月, 2015 8 次提交
    • Z
      btrfs: Fix lockdep warning of wr_ctx->wr_lock in scrub_free_wr_ctx() · 20b2e302
      Zhao Lei 提交于
      lockdep report following warning in test:
       [25176.843958] =================================
       [25176.844519] [ INFO: inconsistent lock state ]
       [25176.845047] 4.1.0-rc3 #22 Tainted: G        W
       [25176.845591] ---------------------------------
       [25176.846153] inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
       [25176.846713] fsstress/26661 [HC0[0]:SC1[1]:HE1:SE0] takes:
       [25176.847246]  (&wr_ctx->wr_lock){+.?...}, at: [<ffffffffa04cdc6d>] scrub_free_ctx+0x2d/0xf0 [btrfs]
       [25176.847838] {SOFTIRQ-ON-W} state was registered at:
       [25176.848396]   [<ffffffff810bf460>] __lock_acquire+0x6a0/0xe10
       [25176.848955]   [<ffffffff810bfd1e>] lock_acquire+0xce/0x2c0
       [25176.849491]   [<ffffffff816489af>] mutex_lock_nested+0x7f/0x410
       [25176.850029]   [<ffffffffa04d04ff>] scrub_stripe+0x4df/0x1080 [btrfs]
       [25176.850575]   [<ffffffffa04d11b1>] scrub_chunk.isra.19+0x111/0x130 [btrfs]
       [25176.851110]   [<ffffffffa04d144c>] scrub_enumerate_chunks+0x27c/0x510 [btrfs]
       [25176.851660]   [<ffffffffa04d3b87>] btrfs_scrub_dev+0x1c7/0x6c0 [btrfs]
       [25176.852189]   [<ffffffffa04e918e>] btrfs_dev_replace_start+0x36e/0x450 [btrfs]
       [25176.852771]   [<ffffffffa04a98e0>] btrfs_ioctl+0x1e10/0x2d20 [btrfs]
       [25176.853315]   [<ffffffff8121c5b8>] do_vfs_ioctl+0x318/0x570
       [25176.853868]   [<ffffffff8121c851>] SyS_ioctl+0x41/0x80
       [25176.854406]   [<ffffffff8164da17>] system_call_fastpath+0x12/0x6f
       [25176.854935] irq event stamp: 51506
       [25176.855511] hardirqs last  enabled at (51506): [<ffffffff810d4ce5>] vprintk_emit+0x225/0x5e0
       [25176.856059] hardirqs last disabled at (51505): [<ffffffff810d4b77>] vprintk_emit+0xb7/0x5e0
       [25176.856642] softirqs last  enabled at (50886): [<ffffffff81067a23>] __do_softirq+0x363/0x640
       [25176.857184] softirqs last disabled at (50949): [<ffffffff8106804d>] irq_exit+0x10d/0x120
       [25176.857746]
       other info that might help us debug this:
       [25176.858845]  Possible unsafe locking scenario:
       [25176.859981]        CPU0
       [25176.860537]        ----
       [25176.861059]   lock(&wr_ctx->wr_lock);
       [25176.861705]   <Interrupt>
       [25176.862272]     lock(&wr_ctx->wr_lock);
       [25176.862881]
        *** DEADLOCK ***
      
      Reason:
       Above warning is caused by:
       Interrupt
       -> bio_endio()
       -> ...
       -> scrub_put_ctx()
       -> scrub_free_ctx() *1
       -> ...
       -> mutex_lock(&wr_ctx->wr_lock);
      
       scrub_put_ctx() is allowed to be called in end_bio interrupt, but
       in code design, it will never call scrub_free_ctx(sctx) in interrupe
       context(above *1), because btrfs_scrub_dev() get one additional
       reference of sctx->refs, which makes scrub_free_ctx() only called
       withine btrfs_scrub_dev().
      
       Now the code runs out of our wish, because free sequence in
       scrub_pending_bio_dec() have a gap.
      
       Current code:
       -----------------------------------+-----------------------------------
       scrub_pending_bio_dec()            |  btrfs_scrub_dev
       -----------------------------------+-----------------------------------
       atomic_dec(&sctx->bios_in_flight); |
       wake_up(&sctx->list_wait);         |
                                          | scrub_put_ctx()
                                          | -> atomic_dec_and_test(&sctx->refs)
       scrub_put_ctx(sctx);               |
       -> atomic_dec_and_test(&sctx->refs)|
       -> scrub_free_ctx()                |
       -----------------------------------+-----------------------------------
      
       We expected:
       -----------------------------------+-----------------------------------
       scrub_pending_bio_dec()            |  btrfs_scrub_dev
       -----------------------------------+-----------------------------------
       atomic_dec(&sctx->bios_in_flight); |
       wake_up(&sctx->list_wait);         |
       scrub_put_ctx(sctx);               |
       -> atomic_dec_and_test(&sctx->refs)|
                                          | scrub_put_ctx()
                                          | -> atomic_dec_and_test(&sctx->refs)
                                          | -> scrub_free_ctx()
       -----------------------------------+-----------------------------------
      
      Fix:
       Move scrub_pending_bio_dec() to a workqueue, to avoid this function run
       in interrupt context.
       Tested by check tracelog in debug.
      
      Changelog v1->v2:
       Use workqueue instead of adjust function call sequence in v1,
       because v1 will introduce a bug pointed out by:
       Filipe David Manana <fdmanana@gmail.com>
      Reported-by: NQu Wenruo <quwenruo@cn.fujitsu.com>
      Signed-off-by: NZhao Lei <zhaolei@cn.fujitsu.com>
      Reviewed-by: NFilipe Manana <fdmanana@suse.com>
      Signed-off-by: NChris Mason <clm@fb.com>
      20b2e302
    • M
      btrfs: Handle unaligned length in extent_same · e1d227a4
      Mark Fasheh 提交于
      The extent-same code rejects requests with an unaligned length. This
      poses a problem when we want to dedupe the tail extent of files as we
      skip cloning the portion between i_size and the extent boundary.
      
      If we don't clone the entire extent, it won't be deleted. So the
      combination of these behaviors winds up giving us worst-case dedupe on
      many files.
      
      We can fix this by allowing a length that extents to i_size and
      internally aligining those to the end of the block. This is what
      btrfs_ioctl_clone() so we can just copy that check over.
      Signed-off-by: NMark Fasheh <mfasheh@suse.de>
      Signed-off-by: NChris Mason <clm@fb.com>
      e1d227a4
    • C
      Btrfs: btrfs_defrag_file: Fix calculation of max_to_defrag. · 070034bd
      chandan 提交于
      max_to_defrag represents the number of pages to defrag rather than the last
      page of the file range to be defragged.
      
      Consider a file having 10 4k blocks (i.e. blocks in the range [0 - 9]). If the
      defrag ioctl was invoked for the block range [3 - 6], then max_to_defrag
      should actually have the value 4. Instead in the current code we end up
      setting it to 6.
      
      Now, this does not (yet) cause an issue since the first part of the while loop
      condition in btrfs_defrag_file() (i.e. "i <= last_index") causes the control
      to flow out of the while loop before any buggy behavior is actually caused. So
      the patch just makes sure that max_to_defrag ends up having the right value
      rather than fixing a bug. I did run the xfstests suite to make sure that the
      code does not regress.
      
      Changelog: v1->v2:
      Provide a much descriptive commit message.
      Signed-off-by: NChandan Rajendra <chandan@linux.vnet.ibm.com>
      Signed-off-by: NChris Mason <clm@fb.com>
      070034bd
    • C
      Btrfs: btrfs_defrag_file: Fix ra_index computation. · e4826a5b
      chandan 提交于
      Read-ahead is done for the pages in the range [ra_index, ra_index + cluster -
      1]. So the next read-ahead should be starting from the page at index 'ra_index
      + cluster' (unless we deemed that the extent at 'ra_index + cluster' as
      non-defraggable) rather than from the page at index 'ra_index +
      max_cluster'. This patch fixes this. I did run the xfstests suite to make sure
      that the code does not regress.
      Signed-off-by: NChandan Rajendra <chandan@linux.vnet.ibm.com>
      Signed-off-by: NChris Mason <clm@fb.com>
      e4826a5b
    • F
      Btrfs: fix necessary chunk tree space calculation when allocating a chunk · 4617ea3a
      Filipe Manana 提交于
      When allocating a new chunk or removing one we need to update num_devs
      device items and insert or remove a chunk item in the chunk tree, so
      in the worst case the space needed in the chunk space_info is:
      
        btrfs_calc_trunc_metadata_size(chunk_root, num_devs) +
           btrfs_calc_trans_metadata_size(chunk_root, 1)
      
      That is, in the worst case we need to cow num_devs paths and cow 1 other
      path that can result in splitting every node and leaf, and each path
      consisting of BTRFS_MAX_LEVEL - 1 nodes and 1 leaf. We were requiring
      some additional chunk_root->nodesize * BTRFS_MAX_LEVEL * num_devs bytes,
      which were unnecessary since updating the existing device items does
      not result in splitting the nodes and leaf since after updating them
      they remain with the same size.
      Signed-off-by: NFilipe Manana <fdmanana@suse.com>
      Signed-off-by: NChris Mason <clm@fb.com>
      4617ea3a
    • F
      Btrfs: don't attach unnecessary extents to transaction on fsync · 7558c8bc
      Filipe Manana 提交于
      We don't need to attach ordered extents that have completed to the current
      transaction. Doing so only makes us hold memory for longer than necessary
      and delaying the iput of the inode until the transaction is committed (for
      each created ordered extent we do an igrab and then schedule an asynchronous
      iput when the ordered extent's reference count drops to 0), preventing the
      inode from being evictable until the transaction commits.
      Signed-off-by: NFilipe Manana <fdmanana@suse.com>
      Signed-off-by: NChris Mason <clm@fb.com>
      7558c8bc
    • F
      Btrfs: avoid syncing log in the fast fsync path when not necessary · b659ef02
      Filipe Manana 提交于
      Commit 3a8b36f3 ("Btrfs: fix data loss in the fast fsync path") added
      a performance regression for that causes an unnecessary sync of the log
      trees (fs/subvol and root log trees) when 2 consecutive fsyncs are done
      against a file, without no writes or any metadata updates to the inode in
      between them and if a transaction is committed before the second fsync is
      called.
      
      Huang Ying reported this to lkml (https://lkml.org/lkml/2015/3/18/99)
      after a test sysbench test that measured a -62% decrease of file io
      requests per second for that tests' workload.
      
      The test is:
      
        echo performance > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
        echo performance > /sys/devices/system/cpu/cpu1/cpufreq/scaling_governor
        echo performance > /sys/devices/system/cpu/cpu2/cpufreq/scaling_governor
        echo performance > /sys/devices/system/cpu/cpu3/cpufreq/scaling_governor
        mkfs -t btrfs /dev/sda2
        mount -t btrfs /dev/sda2 /fs/sda2
        cd /fs/sda2
        for ((i = 0; i < 1024; i++)); do fallocate -l 67108864 testfile.$i; done
        sysbench --test=fileio --max-requests=0 --num-threads=4 --max-time=600 \
          --file-test-mode=rndwr --file-total-size=68719476736 --file-io-mode=sync \
          --file-num=1024 run
      
      A test on kvm guest, running a debug kernel gave me the following results:
      
      Without 3a8b36f3:             16.01 reqs/sec
      With 3a8b36f3:                 3.39 reqs/sec
      With 3a8b36f3 and this patch: 16.04 reqs/sec
      Reported-by: NHuang Ying <ying.huang@intel.com>
      Tested-by: NHuang, Ying <ying.huang@intel.com>
      Signed-off-by: NFilipe Manana <fdmanana@suse.com>
      Signed-off-by: NChris Mason <clm@fb.com>
      b659ef02
    • C
      Merge branch 'send_fixes_4.2' of... · 1ab818b1
      Chris Mason 提交于
      Merge branch 'send_fixes_4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/fdmanana/linux into for-linus-4.2
      1ab818b1
  3. 03 6月, 2015 19 次提交
    • F
      Btrfs: fix hang during inode eviction due to concurrent readahead · 6ca07097
      Filipe Manana 提交于
      Zygo Blaxell and other users have reported occasional hangs while an
      inode is being evicted, leading to traces like the following:
      
      [ 5281.972322] INFO: task rm:20488 blocked for more than 120 seconds.
      [ 5281.973836]       Not tainted 4.0.0-rc5-btrfs-next-9+ #2
      [ 5281.974818] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
      [ 5281.976364] rm              D ffff8800724cfc38     0 20488   7747 0x00000000
      [ 5281.977506]  ffff8800724cfc38 ffff8800724cfc38 ffff880065da5c50 0000000000000001
      [ 5281.978461]  ffff8800724cffd8 ffff8801540a5f50 0000000000000008 ffff8801540a5f78
      [ 5281.979541]  ffff8801540a5f50 ffff8800724cfc58 ffffffff8143107e 0000000000000123
      [ 5281.981396] Call Trace:
      [ 5281.982066]  [<ffffffff8143107e>] schedule+0x74/0x83
      [ 5281.983341]  [<ffffffffa03b33cf>] wait_on_state+0xac/0xcd [btrfs]
      [ 5281.985127]  [<ffffffff81075cd6>] ? signal_pending_state+0x31/0x31
      [ 5281.986715]  [<ffffffffa03b4b71>] wait_extent_bit.constprop.32+0x7c/0xde [btrfs]
      [ 5281.988680]  [<ffffffffa03b540b>] lock_extent_bits+0x5d/0x88 [btrfs]
      [ 5281.990200]  [<ffffffffa03a621d>] btrfs_evict_inode+0x24e/0x5be [btrfs]
      [ 5281.991781]  [<ffffffff8116964d>] evict+0xa0/0x148
      [ 5281.992735]  [<ffffffff8116a43d>] iput+0x18f/0x1e5
      [ 5281.993796]  [<ffffffff81160d4a>] do_unlinkat+0x15b/0x1fa
      [ 5281.994806]  [<ffffffff81435b54>] ? ret_from_sys_call+0x1d/0x58
      [ 5281.996120]  [<ffffffff8107d314>] ? trace_hardirqs_on_caller+0x18f/0x1ab
      [ 5281.997562]  [<ffffffff8123960b>] ? trace_hardirqs_on_thunk+0x3a/0x3f
      [ 5281.998815]  [<ffffffff81161a16>] SyS_unlinkat+0x29/0x2b
      [ 5281.999920]  [<ffffffff81435b32>] system_call_fastpath+0x12/0x17
      [ 5282.001299] 1 lock held by rm/20488:
      [ 5282.002066]  #0:  (sb_writers#12){.+.+.+}, at: [<ffffffff8116dd81>] mnt_want_write+0x24/0x4b
      
      This happens when we have readahead, which calls readpages(), happening
      right before the inode eviction handler is invoked. So the reason is
      essentially:
      
      1) readpages() is called while a reference on the inode is held, so
         eviction can not be triggered before readpages() returns. It also
         locks one or more ranges in the inode's io_tree (which is done at
         extent_io.c:__do_contiguous_readpages());
      
      2) readpages() submits several read bios, all with an end io callback
         that runs extent_io.c:end_bio_extent_readpage() and that is executed
         by other task when a bio finishes, corresponding to a work queue
         (fs_info->end_io_workers) worker kthread. This callback unlocks
         the ranges in the inode's io_tree that were previously locked in
         step 1;
      
      3) readpages() returns, the reference on the inode is dropped;
      
      4) One or more of the read bios previously submitted are still not
         complete (their end io callback was not yet invoked or has not
         yet finished execution);
      
      5) Inode eviction is triggered (through an unlink call for example).
         The inode reference count was not incremented before submitting
         the read bios, therefore this is possible;
      
      6) The eviction handler starts executing and enters the loop that
         iterates over all extent states in the inode's io_tree;
      
      7) The loop picks one extent state record and uses its ->start and
         ->end fields, after releasing the inode's io_tree spinlock, to
         call lock_extent_bits() and clear_extent_bit(). The call to lock
         the range [state->start, state->end] blocks because the whole
         range or a part of it was locked by the previous call to
         readpages() and the corresponding end io callback, which unlocks
         the range was not yet executed;
      
      8) The end io callback for the read bio is executed and unlocks the
         range [state->start, state->end] (or a superset of that range).
         And at clear_extent_bit() the extent_state record state is used
         as a second argument to split_state(), which sets state->start to
         a larger value;
      
      9) The task executing the eviction handler is woken up by the task
         executing the bio's end io callback (through clear_state_bit) and
         the eviction handler locks the range
         [old value for state->start, state->end]. Shortly after, when
         calling clear_extent_bit(), it unlocks the range
         [new value for state->start, state->end], so it ends up unlocking
         only part of the range that it locked, leaving an extent state
         record in the io_tree that represents the unlocked subrange;
      
      10) The eviction handler loop, in its next iteration, gets the
          extent_state record for the subrange that it did not unlock in the
          previous step and then tries to lock it, resulting in an hang.
      
      So fix this by not using the ->start and ->end fields of an existing
      extent_state record. This is a simple solution, and an alternative
      could be to bump the inode's reference count before submitting each
      read bio and having it dropped in the bio's end io callback. But that
      would be a more invasive/complex change and would not protect against
      other possible places that are not holding a reference on the inode
      as well. Something to consider in the future.
      
      Many thanks to Zygo Blaxell for reporting, in the mailing list, the
      issue, a set of scripts to trigger it and testing this fix.
      Reported-by: NZygo Blaxell <ce3g8jdj@umail.furryterror.org>
      Tested-by: NZygo Blaxell <ce3g8jdj@umail.furryterror.org>
      Signed-off-by: NFilipe Manana <fdmanana@suse.com>
      Signed-off-by: NChris Mason <clm@fb.com>
      6ca07097
    • L
      Btrfs: fix up read_tree_block to return proper error · 64c043de
      Liu Bo 提交于
      The return value of read_tree_block() can confuse callers as it always
      returns NULL for either -ENOMEM or -EIO, so it's likely that callers
      parse it to a wrong error, for instance, in btrfs_read_tree_root().
      
      This fixes the above issue.
      Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>
      Reviewed-by: NDavid Sterba <dsterba@suse.cz>
      Signed-off-by: NChris Mason <clm@fb.com>
      64c043de
    • L
      Btrfs: add missing free_extent_buffer · 8635eda9
      Liu Bo 提交于
      read_tree_block may take a reference on the 'eb', a following
      free_extent_buffer is necessary.
      Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>
      Reviewed-by: NDavid Sterba <dsterba@suse.cz>
      Signed-off-by: NChris Mason <clm@fb.com>
      8635eda9
    • L
      Btrfs: remove csum_bytes_left · 0c304304
      Liu Bo 提交于
      After commit 8407f553
      ("Btrfs: fix data corruption after fast fsync and writeback error"),
      during wait_ordered_extents(), we wait for ordered extent setting
      BTRFS_ORDERED_IO_DONE or BTRFS_ORDERED_IOERR, at which point we've
      already got checksum information, so we don't need to check
      (csum_bytes_left == 0) in the whole logging path.
      Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>
      Signed-off-by: NChris Mason <clm@fb.com>
      0c304304
    • F
      Btrfs: fix -ENOSPC on block group removal · 39c2d7fa
      Filipe Manana 提交于
      Unlike when attempting to allocate a new block group, where we check
      that we have enough space in the system space_info to update the device
      items and insert a new chunk item in the chunk tree, we were not checking
      if the system space_info had enough space for updating the device items
      and deleting the chunk item in the chunk tree. This often lead to -ENOSPC
      error when attempting to allocate blocks for the chunk tree (during btree
      node/leaf COW operations) while updating the device items or deleting the
      chunk item, which resulted in the current transaction being aborted and
      turning the filesystem into read-only mode.
      
      While running fstests generic/038, which stresses allocation of block
      groups and removal of unused block groups, with a large scratch device
      (750Gb) this happened often, despite more than enough unallocated space,
      and resulted in the following trace:
      
      [68663.586604] WARNING: CPU: 3 PID: 1521 at fs/btrfs/super.c:260 __btrfs_abort_transaction+0x52/0x114 [btrfs]()
      [68663.600407] BTRFS: Transaction aborted (error -28)
      (...)
      [68663.730829] Call Trace:
      [68663.732585]  [<ffffffff8142fa46>] dump_stack+0x4f/0x7b
      [68663.734334]  [<ffffffff8108b6a2>] ? console_unlock+0x361/0x3ad
      [68663.739980]  [<ffffffff81045ea5>] warn_slowpath_common+0xa1/0xbb
      [68663.757153]  [<ffffffffa036ca6d>] ? __btrfs_abort_transaction+0x52/0x114 [btrfs]
      [68663.760925]  [<ffffffff81045f05>] warn_slowpath_fmt+0x46/0x48
      [68663.762854]  [<ffffffffa03b159d>] ? btrfs_update_device+0x15a/0x16c [btrfs]
      [68663.764073]  [<ffffffffa036ca6d>] __btrfs_abort_transaction+0x52/0x114 [btrfs]
      [68663.765130]  [<ffffffffa03b3638>] btrfs_remove_chunk+0x597/0x5ee [btrfs]
      [68663.765998]  [<ffffffffa0384663>] ? btrfs_delete_unused_bgs+0x245/0x296 [btrfs]
      [68663.767068]  [<ffffffffa0384676>] btrfs_delete_unused_bgs+0x258/0x296 [btrfs]
      [68663.768227]  [<ffffffff8143527f>] ? _raw_spin_unlock_irq+0x2d/0x4c
      [68663.769081]  [<ffffffffa038b109>] cleaner_kthread+0x13d/0x16c [btrfs]
      [68663.799485]  [<ffffffffa038afcc>] ? btrfs_alloc_root+0x28/0x28 [btrfs]
      [68663.809208]  [<ffffffff8105f367>] kthread+0xef/0xf7
      [68663.828795]  [<ffffffff810e603f>] ? time_hardirqs_on+0x15/0x28
      [68663.844942]  [<ffffffff8105f278>] ? __kthread_parkme+0xad/0xad
      [68663.846486]  [<ffffffff81435a88>] ret_from_fork+0x58/0x90
      [68663.847760]  [<ffffffff8105f278>] ? __kthread_parkme+0xad/0xad
      [68663.849503] ---[ end trace 798477c6d6dbaad6 ]---
      [68663.850525] BTRFS: error (device sdc) in btrfs_remove_chunk:2652: errno=-28 No space left
      
      So fix this by verifying that enough space exists in system space_info,
      and reserving the space in the chunk block reserve, before attempting to
      delete the block group and allocate a new system chunk if we don't have
      enough space to perform the necessary updates and delete in the chunk
      tree. Like for the block group creation case, we don't error our if we
      fail to allocate a new system chunk, since we might end up not needing
      it (no node/leaf splits happen during the COW operations and/or we end
      up not needing to COW any btree nodes or leafs because they were already
      COWed in the current transaction and their writeback didn't start yet).
      Signed-off-by: NFilipe Manana <fdmanana@suse.com>
      Signed-off-by: NChris Mason <clm@fb.com>
      39c2d7fa
    • F
      Btrfs: fix -ENOSPC when finishing block group creation · 4fbcdf66
      Filipe Manana 提交于
      While creating a block group, we often end up getting ENOSPC while updating
      the chunk tree, which leads to a transaction abortion that produces a trace
      like the following:
      
      [30670.116368] WARNING: CPU: 4 PID: 20735 at fs/btrfs/super.c:260 __btrfs_abort_transaction+0x52/0x106 [btrfs]()
      [30670.117777] BTRFS: Transaction aborted (error -28)
      (...)
      [30670.163567] Call Trace:
      [30670.163906]  [<ffffffff8142fa46>] dump_stack+0x4f/0x7b
      [30670.164522]  [<ffffffff8108b6a2>] ? console_unlock+0x361/0x3ad
      [30670.165171]  [<ffffffff81045ea5>] warn_slowpath_common+0xa1/0xbb
      [30670.166323]  [<ffffffffa035daa7>] ? __btrfs_abort_transaction+0x52/0x106 [btrfs]
      [30670.167213]  [<ffffffff81045f05>] warn_slowpath_fmt+0x46/0x48
      [30670.167862]  [<ffffffffa035daa7>] __btrfs_abort_transaction+0x52/0x106 [btrfs]
      [30670.169116]  [<ffffffffa03743d7>] btrfs_create_pending_block_groups+0x101/0x130 [btrfs]
      [30670.170593]  [<ffffffffa038426a>] __btrfs_end_transaction+0x84/0x366 [btrfs]
      [30670.171960]  [<ffffffffa038455c>] btrfs_end_transaction+0x10/0x12 [btrfs]
      [30670.174649]  [<ffffffffa036eb6b>] btrfs_check_data_free_space+0x11f/0x27c [btrfs]
      [30670.176092]  [<ffffffffa039450d>] btrfs_fallocate+0x7c8/0xb96 [btrfs]
      [30670.177218]  [<ffffffff812459f2>] ? __this_cpu_preempt_check+0x13/0x15
      [30670.178622]  [<ffffffff81152447>] vfs_fallocate+0x14c/0x1de
      [30670.179642]  [<ffffffff8116b915>] ? __fget_light+0x2d/0x4f
      [30670.180692]  [<ffffffff81152863>] SyS_fallocate+0x47/0x62
      [30670.186737]  [<ffffffff81435b32>] system_call_fastpath+0x12/0x17
      [30670.187792] ---[ end trace 0373e6b491c4a8cc ]---
      
      This is because we don't do proper space reservation for the chunk block
      reserve when we have multiple tasks allocating chunks in parallel.
      
      So block group creation has 2 phases, and the first phase essentially
      checks if there is enough space in the system space_info, allocating a
      new system chunk if there isn't, while the second phase updates the
      device, extent and chunk trees. However, because the updates to the
      chunk tree happen in the second phase, if we have N tasks, each with
      its own transaction handle, allocating new chunks in parallel and if
      there is only enough space in the system space_info to allocate M chunks,
      where M < N, none of the tasks ends up allocating a new system chunk in
      the first phase and N - M tasks will get -ENOSPC when attempting to
      update the chunk tree in phase 2 if they need to COW any nodes/leafs
      from the chunk tree.
      
      Fix this by doing proper reservation in the chunk block reserve.
      
      The issue could be reproduced by running fstests generic/038 in a loop,
      which eventually triggered the problem.
      Signed-off-by: NFilipe Manana <fdmanana@suse.com>
      Signed-off-by: NChris Mason <clm@fb.com>
      4fbcdf66
    • J
      Btrfs: set UNWRITTEN for prealloc'ed extents in fiemap · 0d2b2372
      Josef Bacik 提交于
      We should be doing this, it's weird we hadn't been doing this.
      Signed-off-by: NJosef Bacik <jbacik@fb.com>
      Signed-off-by: NChris Mason <clm@fb.com>
      0d2b2372
    • O
      Btrfs: show subvol= and subvolid= in /proc/mounts · c8d3fe02
      Omar Sandoval 提交于
      Now that we're guaranteed to have a meaningful root dentry, we can just
      export seq_dentry() and use it in btrfs_show_options(). The subvolume ID
      is easy to get and can also be useful, so put that in there, too.
      Reviewed-by: NDavid Sterba <dsterba@suse.cz>
      Signed-off-by: NOmar Sandoval <osandov@osandov.com>
      Signed-off-by: NChris Mason <clm@fb.com>
      c8d3fe02
    • O
      Btrfs: unify subvol= and subvolid= mounting · 05dbe683
      Omar Sandoval 提交于
      Currently, mounting a subvolume with subvolid= takes a different code
      path than mounting with subvol=. This isn't really a big deal except for
      the fact that mounts done with subvolid= or the default subvolume don't
      have a dentry that's connected to the dentry tree like in the subvol=
      case. To unify the code paths, when given subvolid= or using the default
      subvolume ID, translate it into a subvolume name by walking
      ROOT_BACKREFs in the root tree and INODE_REFs in the filesystem trees.
      Reviewed-by: NDavid Sterba <dsterba@suse.cz>
      Signed-off-by: NOmar Sandoval <osandov@osandov.com>
      Signed-off-by: NChris Mason <clm@fb.com>
      05dbe683
    • O
      Btrfs: fail on mismatched subvol and subvolid mount options · bb289b7b
      Omar Sandoval 提交于
      There's nothing to stop a user from passing both subvol= and subvolid=
      to mount, but if they don't refer to the same subvolume, someone is
      going to be surprised at some point. Error out on this case, but allow
      users to pass in both if they do match (which they could, for example,
      get out of /proc/mounts).
      Reviewed-by: NDavid Sterba <dsterba@suse.cz>
      Signed-off-by: NOmar Sandoval <osandov@osandov.com>
      Signed-off-by: NChris Mason <clm@fb.com>
      bb289b7b
    • O
      Btrfs: clean up error handling in mount_subvol() · fa330659
      Omar Sandoval 提交于
      In preparation for new functionality in mount_subvol(), give it
      ownership of subvol_name and tidy up the error paths.
      Reviewed-by: NDavid Sterba <dsterba@suse.cz>
      Signed-off-by: NOmar Sandoval <osandov@osandov.com>
      Signed-off-by: NChris Mason <clm@fb.com>
      fa330659
    • O
      Btrfs: remove all subvol options before mounting top-level · e6e4dbe8
      Omar Sandoval 提交于
      Currently, setup_root_args() substitutes 's/subvol=[^,]*/subvolid=0/'.
      But, this means that if the user passes both a subvol and subvolid for
      some reason, we won't actually mount the top-level when we recursively
      mount. For example, consider:
      
      mkfs.btrfs -f /dev/sdb
      mount /dev/sdb /mnt
      btrfs subvol create /mnt/subvol1 # subvolid=257
      btrfs subvol create /mnt/subvol2 # subvolid=258
      umount /mnt
      mount -osubvol=/subvol1,subvolid=258 /dev/sdb /mnt
      
      In the final mount, subvol=/subvol1,subvolid=258 becomes
      subvolid=0,subvolid=258, and the last option takes precedence, so we
      mount subvol2 and try to look up subvol1 inside of it, which fails.
      
      So, instead, do a thorough scan through the argument list and remove any
      subvol= and subvolid= options, then append subvolid=0 to the end. This
      implicitly makes subvol= take precedence over subvolid=, but we're about
      to add a stricter check for that. This also makes setup_root_args() more
      generic, which we'll need soon.
      Reviewed-by: NDavid Sterba <dsterba@suse.cz>
      Signed-off-by: NOmar Sandoval <osandov@osandov.com>
      Signed-off-by: NChris Mason <clm@fb.com>
      e6e4dbe8
    • O
      Btrfs: lock superblock before remounting for rw subvol · 773cd04e
      Omar Sandoval 提交于
      Since commit 0723a047 ("btrfs: allow mounting btrfs subvolumes with
      different ro/rw options"), when mounting a subvolume read/write when
      another subvolume has previously been mounted read-only, we first do a
      remount. However, this should be done with the superblock locked, as per
      sync_filesystem():
      
      	/*
      	 * We need to be protected against the filesystem going from
      	 * r/o to r/w or vice versa.
      	 */
      	WARN_ON(!rwsem_is_locked(&sb->s_umount));
      
      This WARN_ON can easily be hit with:
      
      mkfs.btrfs -f /dev/vdb
      mount /dev/vdb /mnt
      btrfs subvol create /mnt/vol1
      btrfs subvol create /mnt/vol2
      umount /mnt
      mount -oro,subvol=/vol1 /dev/vdb /mnt
      mount -orw,subvol=/vol2 /dev/vdb /mnt2
      
      Fixes: 0723a047 ("btrfs: allow mounting btrfs subvolumes with different ro/rw options")
      Reviewed-by: NDavid Sterba <dsterba@suse.cz>
      Signed-off-by: NOmar Sandoval <osandov@osandov.com>
      Signed-off-by: NChris Mason <clm@fb.com>
      773cd04e
    • F
      Btrfs: wake up extent state waiters on unlock through clear_extent_bits · 0f31871f
      Filipe Manana 提交于
      When we clear an extent state's EXTENT_LOCKED bit with clear_extent_bits()
      through free_io_failure(), we weren't waking up any tasks waiting for the
      extent's state EXTENT_LOCKED bit, leading to an hang.
      
      So make sure clear_extent_bits() ends up waking up any waiters if the
      bit EXTENT_LOCKED is supplied by its callers.
      
      Zygo Blaxell was experiencing such hangs at inode eviction time after
      file unlinks. Thanks to him for a set of scripts to reproduce the issue.
      Reported-by: NZygo Blaxell <ce3g8jdj@umail.furryterror.org>
      Signed-off-by: NFilipe Manana <fdmanana@suse.com>
      Reviewed-by: NLiu Bo <bo.li.liu@oracle.com>
      Signed-off-by: NChris Mason <clm@fb.com>
      0f31871f
    • F
      Btrfs: fix chunk allocation regression leading to transaction abort · c152b63e
      Filipe Manana 提交于
      With commit 1b984508 ("Btrfs: fix find_free_dev_extent() malfunction
      in case device tree has hole") introduced in the kernel 4.1 merge window,
      we end up using part of a device hole for which there are already pending
      chunks or pinned chunks. Before that commit we didn't use the hole and
      would just move on to the next hole in the device.
      
      However when we adjust the start offset for the chunk allocation and we
      have pinned chunks, we set it blindly to the end offset of the pinned
      chunk we are currently processing, which is dangerous because we can
      have a pending chunk that has a start offset that matches the end offset
      of our pinned chunk - leading us to a case where we end up getting two
      pending chunks that start at the same physical device offset, which makes
      us later abort the current transaction with -EEXIST when finishing the
      chunk allocation at btrfs_create_pending_block_groups():
      
      [194737.659017] ------------[ cut here ]------------
      [194737.660192] WARNING: CPU: 15 PID: 31111 at fs/btrfs/super.c:260 __btrfs_abort_transaction+0x52/0x106 [btrfs]()
      [194737.662209] BTRFS: Transaction aborted (error -17)
      [194737.663175] Modules linked in: btrfs dm_snapshot dm_bufio dm_flakey dm_mod crc32c_generic xor raid6_pq nfsd auth_rpcgss oid_registry nfs_acl nfs lockd grace fscache sunrpc loop fuse
      [194737.674015] CPU: 15 PID: 31111 Comm: xfs_io Tainted: G        W       4.0.0-rc5-btrfs-next-9+ #2
      [194737.675986] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014
      [194737.682999]  0000000000000009 ffff8800564c7a98 ffffffff8142fa46 ffffffff8108b6a2
      [194737.684540]  ffff8800564c7ae8 ffff8800564c7ad8 ffffffff81045ea5 ffff8800564c7b78
      [194737.686017]  ffffffffa0383aa7 00000000ffffffef ffff88000c7ba000 ffff8801a1f66f40
      [194737.687509] Call Trace:
      [194737.688068]  [<ffffffff8142fa46>] dump_stack+0x4f/0x7b
      [194737.689027]  [<ffffffff8108b6a2>] ? console_unlock+0x361/0x3ad
      [194737.690095]  [<ffffffff81045ea5>] warn_slowpath_common+0xa1/0xbb
      [194737.691198]  [<ffffffffa0383aa7>] ? __btrfs_abort_transaction+0x52/0x106 [btrfs]
      [194737.693789]  [<ffffffff81045f05>] warn_slowpath_fmt+0x46/0x48
      [194737.695065]  [<ffffffffa0383aa7>] __btrfs_abort_transaction+0x52/0x106 [btrfs]
      [194737.696806]  [<ffffffffa039a3bd>] btrfs_create_pending_block_groups+0x101/0x130 [btrfs]
      [194737.698683]  [<ffffffffa03aa433>] __btrfs_end_transaction+0x84/0x366 [btrfs]
      [194737.700329]  [<ffffffffa03aa725>] btrfs_end_transaction+0x10/0x12 [btrfs]
      [194737.701924]  [<ffffffffa0394b51>] btrfs_check_data_free_space+0x11f/0x27c [btrfs]
      [194737.703675]  [<ffffffffa03b8ba4>] __btrfs_buffered_write+0x16a/0x4c8 [btrfs]
      [194737.705417]  [<ffffffffa03bb502>] ? btrfs_file_write_iter+0x19a/0x431 [btrfs]
      [194737.707058]  [<ffffffffa03bb511>] ? btrfs_file_write_iter+0x1a9/0x431 [btrfs]
      [194737.708560]  [<ffffffffa03bb68d>] btrfs_file_write_iter+0x325/0x431 [btrfs]
      [194737.710673]  [<ffffffff81067d85>] ? get_parent_ip+0xe/0x3e
      [194737.712076]  [<ffffffff811534c3>] new_sync_write+0x7c/0xa0
      [194737.713293]  [<ffffffff81153b58>] vfs_write+0xb2/0x117
      [194737.714443]  [<ffffffff81154424>] SyS_pwrite64+0x64/0x82
      [194737.715646]  [<ffffffff81435b32>] system_call_fastpath+0x12/0x17
      [194737.717175] ---[ end trace f2d5dc04e56d7e48 ]---
      [194737.718170] BTRFS: error (device sdc) in btrfs_create_pending_block_groups:9524: errno=-17 Object already exists
      
      The -EEXIST failure comes from btrfs_finish_chunk_alloc(), called by
      btrfs_create_pending_block_groups(), when it attempts to insert a
      duplicated device extent item via btrfs_alloc_dev_extent().
      
      This issue was reproducible with fstests generic/038 running in a loop for
      several hours (it's very hard to hit) and using MOUNT_OPTIONS="-o discard".
      Applying Jeff's recent patch titled "btrfs: add missing discards when
      unpinning extents with -o discard" makes the issue much easier to reproduce
      (usually within 4 to 5 hours), since it pins chunks for longer periods of
      time when an unused block group is deleted by the cleaner kthread.
      
      Fix this by making sure that we never adjust the start offset to a lower
      value than it currently has.
      
      Fixes: 1b984508 ("Btrfs: fix find_free_dev_extent() malfunction in case device tree has hole"
      Signed-off-by: NFilipe Manana <fdmanana@suse.com>
      Signed-off-by: NChris Mason <clm@fb.com>
      c152b63e
    • S
      btrfs: use after free when closing devices · 2037a093
      Sasha Levin 提交于
      __btrfs_close_devices() would call_rcu to free the device, which is racy with
      list_for_each_entry() accessing the memory to retrieve the next device on the
      list.
      Signed-off-by: NSasha Levin <sasha.levin@oracle.com>
      Reviewed-by: NDavid Sterba <dsterba@suse.cz>
      Signed-off-by: NChris Mason <clm@fb.com>
      2037a093
    • D
      btrfs: make root id query unprivileged · 01b810b8
      David Sterba 提交于
      The INO_LOOKUP ioctl can lookup path for a given inode number and is
      thus restricted. As a sideefect it can find the root id of the
      containing subvolume and we're using this int the 'btrfs inspect rootid'
      command.
      
      The restriction is unnecessary in case we set the ioctl args
       args::treeid    = 0
       args::objectid  = 256 (BTRFS_FIRST_FREE_OBJECTID)
      
      Then the path will be empty and the treeid is filled with the root id of
      the inode on which the ioctl is called. This behaviour is unchanged,
      after the root restriction is removed.
      Signed-off-by: NDavid Sterba <dsterba@suse.cz>
      Signed-off-by: NChris Mason <clm@fb.com>
      01b810b8
    • F
      Btrfs: fix block group ->space_info null pointer dereference · 2e6e5183
      Filipe Manana 提交于
      When we create a block group we add it to the rbtree of block groups
      before setting its ->space_info field (while it's NULL). This is
      problematic since other tasks can access the block group from the
      rbtree and attempt to use its ->space_info before it is set by
      btrfs_make_block_group().
      
      This can happen for example when a concurrent fitrim ioctl operation
      is ongoing, which produces a trace like the following when
      CONFIG_DEBUG_PAGEALLOC is set.
      
      [11509.604369] BUG: unable to handle kernel NULL pointer dereference at 0000000000000018
      [11509.606373] IP: [<ffffffff8107d675>] __lock_acquire+0xb4/0xf02
      [11509.608179] PGD 2296a8067 PUD 22f4a2067 PMD 0
      [11509.608179] Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
      [11509.608179] Modules linked in: btrfs crc32c_generic xor raid6_pq nfsd auth_rpcgss oid_registry nfs_acl nfs lockd grace fscache sunrpc loop fuse acpi_cpufreq processor i2c_piix4 psmou
      [11509.608179] CPU: 10 PID: 8538 Comm: fstrim Tainted: G        W       4.0.0-rc5-btrfs-next-9+ #2
      [11509.608179] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014
      [11509.608179] task: ffff88009f5c46d0 ti: ffff8801b3edc000 task.ti: ffff8801b3edc000
      [11509.608179] RIP: 0010:[<ffffffff8107d675>]  [<ffffffff8107d675>] __lock_acquire+0xb4/0xf02
      [11509.608179] RSP: 0018:ffff8801b3edf9e8  EFLAGS: 00010002
      [11509.608179] RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000000
      [11509.608179] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000018
      [11509.608179] RBP: ffff8801b3edfaa8 R08: 0000000000000001 R09: 0000000000000000
      [11509.608179] R10: 0000000000000000 R11: ffff88009f5c4f98 R12: 0000000000000000
      [11509.608179] R13: 0000000000000000 R14: 0000000000000018 R15: ffff88009f5c46d0
      [11509.608179] FS:  00007f280a10e840(0000) GS:ffff88023ed40000(0000) knlGS:0000000000000000
      [11509.608179] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
      [11509.608179] CR2: 0000000000000018 CR3: 00000002119bc000 CR4: 00000000000006e0
      [11509.608179] Stack:
      [11509.608179]  0000000000000000 0000000000000000 0000000000000004 0000000000000000
      [11509.608179]  ffff880100000000 ffffffff00000000 0000000000000001 ffffffff00000000
      [11509.608179]  0000000000000001 0000000000000000 ffff880100000000 00000000000006c4
      [11509.608179] Call Trace:
      [11509.608179]  [<ffffffff8107dc57>] ? __lock_acquire+0x696/0xf02
      [11509.608179]  [<ffffffff8107e806>] lock_acquire+0xa5/0x116
      [11509.608179]  [<ffffffffa04cc876>] ? do_trimming+0x51/0x145 [btrfs]
      [11509.608179]  [<ffffffff81434f37>] _raw_spin_lock+0x34/0x44
      [11509.608179]  [<ffffffffa04cc876>] ? do_trimming+0x51/0x145 [btrfs]
      [11509.608179]  [<ffffffffa04cc876>] do_trimming+0x51/0x145 [btrfs]
      [11509.608179]  [<ffffffffa04cde7d>] btrfs_trim_block_group+0x201/0x491 [btrfs]
      [11509.608179]  [<ffffffffa04849e2>] btrfs_trim_fs+0xe0/0x129 [btrfs]
      [11509.608179]  [<ffffffffa04bb80a>] btrfs_ioctl_fitrim+0x138/0x167 [btrfs]
      [11509.608179]  [<ffffffffa04c002f>] btrfs_ioctl+0x50d/0x21e8 [btrfs]
      [11509.608179]  [<ffffffff81123bda>] ? might_fault+0x58/0xb5
      [11509.608179]  [<ffffffff81123bda>] ? might_fault+0x58/0xb5
      [11509.608179]  [<ffffffff81123bda>] ? might_fault+0x58/0xb5
      [11509.608179]  [<ffffffff81158050>] ? cp_new_stat+0x147/0x15e
      [11509.608179]  [<ffffffff81163041>] do_vfs_ioctl+0x3c6/0x479
      [11509.608179]  [<ffffffff81158116>] ? SYSC_newfstat+0x25/0x2e
      [11509.608179]  [<ffffffff81435b54>] ? ret_from_sys_call+0x1d/0x58
      [11509.608179]  [<ffffffff8116b915>] ? __fget_light+0x2d/0x4f
      [11509.608179]  [<ffffffff8116314e>] SyS_ioctl+0x5a/0x7f
      [11509.608179]  [<ffffffff81435b32>] system_call_fastpath+0x12/0x17
      [11509.608179] Code: f4 01 00 0f 85 c0 00 00 00 48 c7 c1 f3 1f 7d 81 48 c7 c2 aa cb 7c 81 be fc 0b 00 00 eb 70 83 3d 61 eb 9c 00 00 0f 84 a5 00 00 00 <49> 81 3e 40 a3 2b 82 b8 00 00 00
      [11509.608179] RIP  [<ffffffff8107d675>] __lock_acquire+0xb4/0xf02
      [11509.608179]  RSP <ffff8801b3edf9e8>
      [11509.608179] CR2: 0000000000000018
      [11509.608179] ---[ end trace 570a5c6769f0e49a ]---
      
      Which corresponds to the following access in fs/btrfs/free-space-cache.c:
      
        static int do_trimming(struct btrfs_block_group_cache *block_group,
                               u64 *total_trimmed, u64 start, u64 bytes,
                               u64 reserved_start, u64 reserved_bytes,
                               struct btrfs_trim_range *trim_entry)
        {
             struct btrfs_space_info *space_info = block_group->space_info;
        (...)
             spin_lock(&space_info->lock);
             ^^^^^ - block_group->space_info is NULL...
      
      Fix this by ensuring the block group's ->space_info is set before adding
      the block group to the rbtree.
      Signed-off-by: NFilipe Manana <fdmanana@suse.com>
      Signed-off-by: NChris Mason <clm@fb.com>
      2e6e5183
    • A
      Btrfs: check error before reporting missing device and add uuid · 33b97e43
      Anand Jain 提交于
      Report missing device when add is successful,
      otherwise it would exit as ENOMEM. And add uuid
      to the report.
      Signed-off-by: NAnand Jain <anand.jain@oracle.com>
      Reviewed-by: NDavid Sterba <dsterba@suse.cz>
      Signed-off-by: NChris Mason <clm@fb.com>
      33b97e43