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  1. May 06, 2016
    • Zygo Blaxell's avatar
      btrfs: don't force mounts to wait for cleaner_kthread to delete one or more subvolumes · 2f3165ec
      Zygo Blaxell authored
      During a mount, we start the cleaner kthread first because the transaction
      kthread wants to wake up the cleaner kthread.  We start the transaction
      kthread next because everything in btrfs wants transactions.  We do reloc
      recovery in the thread that was doing the original mount call once the
      transaction kthread is running.  This means that the cleaner kthread
      could already be running when reloc recovery happens (e.g. if a snapshot
      delete was started before a crash).
      
      Relocation does not play well with the cleaner kthread, so a mutex was
      added in commit 5f316481
      
       "Btrfs: fix
      race between balance recovery and root deletion" to prevent both from
      being active at the same time.
      
      If the cleaner kthread is already holding the mutex by the time we get
      to btrfs_recover_relocation, the mount will be blocked until at least
      one deleted subvolume is cleaned (possibly more if the mount process
      doesn't get the lock right away).  During this time (which could be an
      arbitrarily long time on a large/slow filesystem), the mount process is
      stuck and the filesystem is unnecessarily inaccessible.
      
      Fix this by locking cleaner_mutex before we start cleaner_kthread, and
      unlocking the mutex after mount no longer requires it.  This ensures
      that the mounting process will not be blocked by the cleaner kthread.
      The cleaner kthread is already prepared for mutex contention and will
      just go to sleep until the mutex is available.
      
      Signed-off-by: default avatarZygo Blaxell <ce3g8jdj@umail.furryterror.org>
      Reviewed-by: default avatarFilipe Manana <fdmanana@suse.com>
      Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
      2f3165ec
    • David Sterba's avatar
      btrfs: ioctl: reorder exclusive op check in RM_DEV · 58d7bbf8
      David Sterba authored
      
      
      Move the op exclusivity check before the other code (same as in
      ADD_DEV).
      
      Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
      58d7bbf8
    • David Sterba's avatar
      btrfs: add write protection to SET_FEATURES ioctl · 7ab19625
      David Sterba authored
      
      
      Perform the want_write check if we get far enough to do any writes.
      
      Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
      7ab19625
    • Anand Jain's avatar
      btrfs: fix lock dep warning move scratch super outside of chunk_mutex · 48b3b9d4
      Anand Jain authored
      Move scratch super outside of the chunk lock to avoid below
      lockdep warning. The better place to scratch super is in
      the function btrfs_rm_dev_replace_free_srcdev() just before
      free_device, which is outside of the chunk lock as well.
      
      To reproduce:
        (fresh boot)
        mkfs.btrfs -f -draid5 -mraid5 /dev/sdc /dev/sdd /dev/sde
        mount /dev/sdc /btrfs
        dd if=/dev/zero of=/btrfs/tf1 bs=4096 count=100
        (get devmgt from https://github.com/asj/devmgt.git
      
      )
        devmgt detach /dev/sde
        dd if=/dev/zero of=/btrfs/tf1 bs=4096 count=100
        sync
        btrfs replace start -Brf 3 /dev/sdf /btrfs <--
        devmgt attach host7
      
      ======================================================
      [ INFO: possible circular locking dependency detected ]
      4.6.0-rc2asj+ #1 Not tainted
      ---------------------------------------------------
      
      btrfs/2174 is trying to acquire lock:
      (sb_writers){.+.+.+}, at:
      [<ffffffff812449b4>] __sb_start_write+0xb4/0xf0
      
      but task is already holding lock:
      (&fs_info->chunk_mutex){+.+.+.}, at:
      [<ffffffffa05c5f55>] btrfs_dev_replace_finishing+0x145/0x980 [btrfs]
      
      which lock already depends on the new lock.
      
      Chain exists of:
      sb_writers --> &fs_devs->device_list_mutex --> &fs_info->chunk_mutex
      Possible unsafe locking scenario:
      CPU0				CPU1
      ----				----
      lock(&fs_info->chunk_mutex);
      				lock(&fs_devs->device_list_mutex);
      				lock(&fs_info->chunk_mutex);
      lock(sb_writers);
      
      *** DEADLOCK ***
      
      -> #0 (sb_writers){.+.+.+}:
      [<ffffffff810e6415>] __lock_acquire+0x1bc5/0x1ee0
      [<ffffffff810e707e>] lock_acquire+0xbe/0x210
      [<ffffffff810df49a>] percpu_down_read+0x4a/0xa0
      [<ffffffff812449b4>] __sb_start_write+0xb4/0xf0
      [<ffffffff81265534>] mnt_want_write+0x24/0x50
      [<ffffffff812508a2>] path_openat+0x952/0x1190
      [<ffffffff81252451>] do_filp_open+0x91/0x100
      [<ffffffff8123f5cc>] file_open_name+0xfc/0x140
      [<ffffffff8123f643>] filp_open+0x33/0x60
      [<ffffffffa0572bb6>] update_dev_time+0x16/0x40 [btrfs]
      [<ffffffffa057f60d>] btrfs_scratch_superblocks+0x5d/0xb0 [btrfs]
      [<ffffffffa057f70e>] btrfs_rm_dev_replace_remove_srcdev+0xae/0xd0 [btrfs]
      [<ffffffffa05c62c5>] btrfs_dev_replace_finishing+0x4b5/0x980 [btrfs]
      [<ffffffffa05c6ae8>] btrfs_dev_replace_start+0x358/0x530 [btrfs]
      
      Signed-off-by: default avatarAnand Jain <anand.jain@oracle.com>
      Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
      48b3b9d4
    • Ashish Samant's avatar
      btrfs: Fix BUG_ON condition in scrub_setup_recheck_block() · 24731149
      Ashish Samant authored
      
      
      pagev array in scrub_block{} is of size SCRUB_MAX_PAGES_PER_BLOCK.
      page_index should be checked with the same to trigger BUG_ON().
      
      Signed-off-by: default avatarAshish Samant <ashish.samant@oracle.com>
      Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
      Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
      24731149
    • Josef Bacik's avatar
      Btrfs: remove BUG_ON()'s in btrfs_map_block · e042d1ec
      Josef Bacik authored
      
      
      btrfs_map_block can go horribly wrong in the face of fs corruption, lets agree
      to not be assholes and panic at any possible chance things are all fucked up.
      
      Signed-off-by: default avatarJosef Bacik <jbacik@fb.com>
      [ removed type casts ]
      Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
      e042d1ec
    • Liu Bo's avatar
      Btrfs: fix divide error upon chunk's stripe_len · 3d8da678
      Liu Bo authored
      
      
      The struct 'map_lookup' uses type int for @stripe_len, while
      btrfs_chunk_stripe_len() can return a u64 value, and it may end up with
      @stripe_len being undefined value and it can lead to 'divide error' in
       __btrfs_map_block().
      
      This changes 'map_lookup' to use type u64 for stripe_len, also right now
      we only use BTRFS_STRIPE_LEN for stripe_len, so this adds a valid checker for
      BTRFS_STRIPE_LEN.
      
      Reported-by: default avatarVegard Nossum <vegard.nossum@oracle.com>
      Reported-by: default avatarQuentin Casasnovas <quentin.casasnovas@oracle.com>
      Signed-off-by: default avatarLiu Bo <bo.li.liu@oracle.com>
      Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
      [ folded division fix to scrub_raid56_parity ]
      Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
      3d8da678
    • David Sterba's avatar
      btrfs: sysfs: protect reading label by lock · ee17fc80
      David Sterba authored
      
      
      If the label setting ioctl races with sysfs label handler, we could get
      mixed result in the output, part old part new. We should either get the
      old or new label. The chances to hit this race are low.
      
      Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
      ee17fc80
    • David Sterba's avatar
      btrfs: add check to sysfs handler of label · 66ac9fe7
      David Sterba authored
      
      
      Add a sanity check for the fs_info as we will dereference it, similar to
      what the 'store features' handler does.
      
      Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
      66ac9fe7
    • David Sterba's avatar
      btrfs: add read-only check to sysfs handler of features · ee611138
      David Sterba authored
      
      
      We don't want to trigger the change on a read-only filesystem, similar
      to what the label handler does.
      
      Signed-off-by: default avatarDavid Sterba <dsterba@suse.cz>
      ee611138
    • David Sterba's avatar
      btrfs: reuse existing variable in scrub_stripe, reduce stack usage · e6c11f9a
      David Sterba authored
      
      
      The key variable occupies 17 bytes, the key_start is used once, we can
      simply reuse existing 'key' for that purpose. As the key is not a simple
      type, compiler doest not do it on itself.
      
      Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
      e6c11f9a
    • David Sterba's avatar
      btrfs: use dynamic allocation for root item in create_subvol · 49a3c4d9
      David Sterba authored
      
      
      The size of root item is more than 400 bytes, which is quite a lot of
      stack space. As we do IO from inside the subvolume ioctls, we should
      keep the stack usage low in case the filesystem is on top of other
      layers (NFS, device mapper, iscsi, etc).
      
      Reviewed-by: default avatarTsutomu Itoh <t-itoh@jp.fujitsu.com>
      Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
      49a3c4d9
    • David Sterba's avatar
    • David Sterba's avatar
    • David Sterba's avatar
    • David Sterba's avatar
      btrfs: send: use temporary variable to store allocation size · e55d1153
      David Sterba authored
      
      
      We're going to use the argument multiple times later.
      
      Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
      e55d1153
    • David Sterba's avatar
      eb5b75fe
    • David Sterba's avatar
      6ff48ce0
    • Anand Jain's avatar
      btrfs: fix lock dep warning, move scratch dev out of device_list_mutex and uuid_mutex · 779bf3fe
      Anand Jain authored
      
      
      When the replace target fails, the target device will be taken
      out of fs device list, scratch + update_dev_time and freed. However
      we could do the scratch  + update_dev_time and free part after the
      device has been taken out of device list, so that we don't have to
      hold the device_list_mutex and uuid_mutex locks.
      
      Reported issue:
      
      [ 5375.718845] ======================================================
      [ 5375.718846] [ INFO: possible circular locking dependency detected ]
      [ 5375.718849] 4.4.5-scst31x-debug-11+ #40 Not tainted
      [ 5375.718849] -------------------------------------------------------
      [ 5375.718851] btrfs-health/4662 is trying to acquire lock:
      [ 5375.718861]  (sb_writers){.+.+.+}, at: [<ffffffff812214f7>] __sb_start_write+0xb7/0xf0
      [ 5375.718862]
      [ 5375.718862] but task is already holding lock:
      [ 5375.718907]  (&fs_devs->device_list_mutex){+.+.+.}, at: [<ffffffffa028263c>] btrfs_destroy_dev_replace_tgtdev+0x3c/0x150 [btrfs]
      [ 5375.718907]
      [ 5375.718907] which lock already depends on the new lock.
      [ 5375.718907]
      [ 5375.718908]
      [ 5375.718908] the existing dependency chain (in reverse order) is:
      [ 5375.718911]
      [ 5375.718911] -> #3 (&fs_devs->device_list_mutex){+.+.+.}:
      [ 5375.718917]        [<ffffffff810da4be>] lock_acquire+0xce/0x1e0
      [ 5375.718921]        [<ffffffff81633949>] mutex_lock_nested+0x69/0x3c0
      [ 5375.718940]        [<ffffffffa0219bf6>] btrfs_show_devname+0x36/0x210 [btrfs]
      [ 5375.718945]        [<ffffffff81267079>] show_vfsmnt+0x49/0x150
      [ 5375.718948]        [<ffffffff81240b07>] m_show+0x17/0x20
      [ 5375.718951]        [<ffffffff81246868>] seq_read+0x2d8/0x3b0
      [ 5375.718955]        [<ffffffff8121df28>] __vfs_read+0x28/0xd0
      [ 5375.718959]        [<ffffffff8121e806>] vfs_read+0x86/0x130
      [ 5375.718962]        [<ffffffff8121f4c9>] SyS_read+0x49/0xa0
      [ 5375.718966]        [<ffffffff81637976>] entry_SYSCALL_64_fastpath+0x16/0x7a
      [ 5375.718968]
      [ 5375.718968] -> #2 (namespace_sem){+++++.}:
      [ 5375.718971]        [<ffffffff810da4be>] lock_acquire+0xce/0x1e0
      [ 5375.718974]        [<ffffffff81635199>] down_write+0x49/0x80
      [ 5375.718977]        [<ffffffff81243593>] lock_mount+0x43/0x1c0
      [ 5375.718979]        [<ffffffff81243c13>] do_add_mount+0x23/0xd0
      [ 5375.718982]        [<ffffffff81244afb>] do_mount+0x27b/0xe30
      [ 5375.718985]        [<ffffffff812459dc>] SyS_mount+0x8c/0xd0
      [ 5375.718988]        [<ffffffff81637976>] entry_SYSCALL_64_fastpath+0x16/0x7a
      [ 5375.718991]
      [ 5375.718991] -> #1 (&sb->s_type->i_mutex_key#5){+.+.+.}:
      [ 5375.718994]        [<ffffffff810da4be>] lock_acquire+0xce/0x1e0
      [ 5375.718996]        [<ffffffff81633949>] mutex_lock_nested+0x69/0x3c0
      [ 5375.719001]        [<ffffffff8122d608>] path_openat+0x468/0x1360
      [ 5375.719004]        [<ffffffff8122f86e>] do_filp_open+0x7e/0xe0
      [ 5375.719007]        [<ffffffff8121da7b>] do_sys_open+0x12b/0x210
      [ 5375.719010]        [<ffffffff8121db7e>] SyS_open+0x1e/0x20
      [ 5375.719013]        [<ffffffff81637976>] entry_SYSCALL_64_fastpath+0x16/0x7a
      [ 5375.719015]
      [ 5375.719015] -> #0 (sb_writers){.+.+.+}:
      [ 5375.719018]        [<ffffffff810d97ca>] __lock_acquire+0x17ba/0x1ae0
      [ 5375.719021]        [<ffffffff810da4be>] lock_acquire+0xce/0x1e0
      [ 5375.719026]        [<ffffffff810d3bef>] percpu_down_read+0x4f/0xa0
      [ 5375.719028]        [<ffffffff812214f7>] __sb_start_write+0xb7/0xf0
      [ 5375.719031]        [<ffffffff81242eb4>] mnt_want_write+0x24/0x50
      [ 5375.719035]        [<ffffffff8122ded2>] path_openat+0xd32/0x1360
      [ 5375.719037]        [<ffffffff8122f86e>] do_filp_open+0x7e/0xe0
      [ 5375.719040]        [<ffffffff8121d8a4>] file_open_name+0xe4/0x130
      [ 5375.719043]        [<ffffffff8121d923>] filp_open+0x33/0x60
      [ 5375.719073]        [<ffffffffa02776a6>] update_dev_time+0x16/0x40 [btrfs]
      [ 5375.719099]        [<ffffffffa02825be>] btrfs_scratch_superblocks+0x4e/0x90 [btrfs]
      [ 5375.719123]        [<ffffffffa0282665>] btrfs_destroy_dev_replace_tgtdev+0x65/0x150 [btrfs]
      [ 5375.719150]        [<ffffffffa02c6c80>] btrfs_dev_replace_finishing+0x6b0/0x990 [btrfs]
      [ 5375.719175]        [<ffffffffa02c729e>] btrfs_dev_replace_start+0x33e/0x540 [btrfs]
      [ 5375.719199]        [<ffffffffa02c7f58>] btrfs_auto_replace_start+0xf8/0x140 [btrfs]
      [ 5375.719222]        [<ffffffffa02464e6>] health_kthread+0x246/0x490 [btrfs]
      [ 5375.719225]        [<ffffffff810a70df>] kthread+0xef/0x110
      [ 5375.719229]        [<ffffffff81637d2f>] ret_from_fork+0x3f/0x70
      [ 5375.719230]
      [ 5375.719230] other info that might help us debug this:
      [ 5375.719230]
      [ 5375.719233] Chain exists of:
      [ 5375.719233]   sb_writers --> namespace_sem --> &fs_devs->device_list_mutex
      [ 5375.719233]
      [ 5375.719234]  Possible unsafe locking scenario:
      [ 5375.719234]
      [ 5375.719234]        CPU0                    CPU1
      [ 5375.719235]        ----                    ----
      [ 5375.719236]   lock(&fs_devs->device_list_mutex);
      [ 5375.719238]                                lock(namespace_sem);
      [ 5375.719239]                                lock(&fs_devs->device_list_mutex);
      [ 5375.719241]   lock(sb_writers);
      [ 5375.719241]
      [ 5375.719241]  *** DEADLOCK ***
      [ 5375.719241]
      [ 5375.719243] 4 locks held by btrfs-health/4662:
      [ 5375.719266]  #0:  (&fs_info->health_mutex){+.+.+.}, at: [<ffffffffa0246303>] health_kthread+0x63/0x490 [btrfs]
      [ 5375.719293]  #1:  (&fs_info->dev_replace.lock_finishing_cancel_unmount){+.+.+.}, at: [<ffffffffa02c6611>] btrfs_dev_replace_finishing+0x41/0x990 [btrfs]
      [ 5375.719319]  #2:  (uuid_mutex){+.+.+.}, at: [<ffffffffa0282620>] btrfs_destroy_dev_replace_tgtdev+0x20/0x150 [btrfs]
      [ 5375.719343]  #3:  (&fs_devs->device_list_mutex){+.+.+.}, at: [<ffffffffa028263c>] btrfs_destroy_dev_replace_tgtdev+0x3c/0x150 [btrfs]
      [ 5375.719343]
      [ 5375.719343] stack backtrace:
      [ 5375.719347] CPU: 2 PID: 4662 Comm: btrfs-health Not tainted 4.4.5-scst31x-debug-11+ #40
      [ 5375.719348] Hardware name: Supermicro SYS-6018R-WTRT/X10DRW-iT, BIOS 1.0c 01/07/2015
      [ 5375.719352]  0000000000000000 ffff880856f73880 ffffffff813529e3 ffffffff826182a0
      [ 5375.719354]  ffffffff8260c090 ffff880856f738c0 ffffffff810d667c ffff880856f73930
      [ 5375.719357]  ffff880861f32b40 ffff880861f32b68 0000000000000003 0000000000000004
      [ 5375.719357] Call Trace:
      [ 5375.719363]  [<ffffffff813529e3>] dump_stack+0x85/0xc2
      [ 5375.719366]  [<ffffffff810d667c>] print_circular_bug+0x1ec/0x260
      [ 5375.719369]  [<ffffffff810d97ca>] __lock_acquire+0x17ba/0x1ae0
      [ 5375.719373]  [<ffffffff810f606d>] ? debug_lockdep_rcu_enabled+0x1d/0x20
      [ 5375.719376]  [<ffffffff810da4be>] lock_acquire+0xce/0x1e0
      [ 5375.719378]  [<ffffffff812214f7>] ? __sb_start_write+0xb7/0xf0
      [ 5375.719383]  [<ffffffff810d3bef>] percpu_down_read+0x4f/0xa0
      [ 5375.719385]  [<ffffffff812214f7>] ? __sb_start_write+0xb7/0xf0
      [ 5375.719387]  [<ffffffff812214f7>] __sb_start_write+0xb7/0xf0
      [ 5375.719389]  [<ffffffff81242eb4>] mnt_want_write+0x24/0x50
      [ 5375.719393]  [<ffffffff8122ded2>] path_openat+0xd32/0x1360
      [ 5375.719415]  [<ffffffffa02462a0>] ? btrfs_congested_fn+0x180/0x180 [btrfs]
      [ 5375.719418]  [<ffffffff810f606d>] ? debug_lockdep_rcu_enabled+0x1d/0x20
      [ 5375.719420]  [<ffffffff8122f86e>] do_filp_open+0x7e/0xe0
      [ 5375.719423]  [<ffffffff810f615d>] ? rcu_read_lock_sched_held+0x6d/0x80
      [ 5375.719426]  [<ffffffff81201a9b>] ? kmem_cache_alloc+0x26b/0x5d0
      [ 5375.719430]  [<ffffffff8122e7d4>] ? getname_kernel+0x34/0x120
      [ 5375.719433]  [<ffffffff8121d8a4>] file_open_name+0xe4/0x130
      [ 5375.719436]  [<ffffffff8121d923>] filp_open+0x33/0x60
      [ 5375.719462]  [<ffffffffa02776a6>] update_dev_time+0x16/0x40 [btrfs]
      [ 5375.719485]  [<ffffffffa02825be>] btrfs_scratch_superblocks+0x4e/0x90 [btrfs]
      [ 5375.719506]  [<ffffffffa0282665>] btrfs_destroy_dev_replace_tgtdev+0x65/0x150 [btrfs]
      [ 5375.719530]  [<ffffffffa02c6c80>] btrfs_dev_replace_finishing+0x6b0/0x990 [btrfs]
      [ 5375.719554]  [<ffffffffa02c6b23>] ? btrfs_dev_replace_finishing+0x553/0x990 [btrfs]
      [ 5375.719576]  [<ffffffffa02c729e>] btrfs_dev_replace_start+0x33e/0x540 [btrfs]
      [ 5375.719598]  [<ffffffffa02c7f58>] btrfs_auto_replace_start+0xf8/0x140 [btrfs]
      [ 5375.719621]  [<ffffffffa02464e6>] health_kthread+0x246/0x490 [btrfs]
      [ 5375.719641]  [<ffffffffa02463d8>] ? health_kthread+0x138/0x490 [btrfs]
      [ 5375.719661]  [<ffffffffa02462a0>] ? btrfs_congested_fn+0x180/0x180 [btrfs]
      [ 5375.719663]  [<ffffffff810a70df>] kthread+0xef/0x110
      [ 5375.719666]  [<ffffffff810a6ff0>] ? kthread_create_on_node+0x200/0x200
      [ 5375.719669]  [<ffffffff81637d2f>] ret_from_fork+0x3f/0x70
      [ 5375.719672]  [<ffffffff810a6ff0>] ? kthread_create_on_node+0x200/0x200
      [ 5375.719697] ------------[ cut here ]------------
      
      Signed-off-by: default avatarAnand Jain <anand.jain@oracle.com>
      Reported-by: default avatarYauhen Kharuzhy <yauhen.kharuzhy@zavadatar.com>
      Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
      779bf3fe
    • Dan Carpenter's avatar
      btrfs: send: silence an integer overflow warning · f5ecec3c
      Dan Carpenter authored
      
      
      The "sizeof(*arg->clone_sources) * arg->clone_sources_count" expression
      can overflow.  It causes several static checker warnings.  It's all
      under CAP_SYS_ADMIN so it's not that serious but lets silence the
      warnings.
      
      Signed-off-by: default avatarDan Carpenter <dan.carpenter@oracle.com>
      Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
      Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
      f5ecec3c
    • Luis de Bethencourt's avatar
      btrfs: avoid overflowing f_bfree · 41b34acc
      Luis de Bethencourt authored
      
      
      Since mixed block groups accounting isn't byte-accurate and f_bree is an
      unsigned integer, it could overflow. Avoid this.
      
      Signed-off-by: default avatarLuis de Bethencourt <luisbg@osg.samsung.com>
      Suggested-by: default avatarDavid Sterba <dsterba@suse.com>
      Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
      41b34acc
    • Luis de Bethencourt's avatar
      btrfs: fix mixed block count of available space · ae02d1bd
      Luis de Bethencourt authored
      
      
      Metadata for mixed block is already accounted in total data and should not
      be counted as part of the free metadata space.
      
      Signed-off-by: default avatarLuis de Bethencourt <luisbg@osg.samsung.com>
      Link: https://bugzilla.kernel.org/show_bug.cgi?id=114281
      
      
      Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
      ae02d1bd
    • Austin S. Hemmelgarn's avatar
      btrfs: allow balancing to dup with multi-device · 88be159c
      Austin S. Hemmelgarn authored
      
      
      Currently, we don't allow the user to try and rebalance to a dup profile
      on a multi-device filesystem.  In most cases, this is a perfectly sensible
      restriction as raid1 uses the same amount of space and provides better
      protection.
      
      However, when reshaping a multi-device filesystem down to a single device
      filesystem, this requires the user to convert metadata and system chunks
      to single profile before deleting devices, and then convert again to dup,
      which leaves a period of time where metadata integrity is reduced.
      
      This patch removes the single-device-only restriction from converting to
      dup profile to remove this potential data integrity reduction.
      
      Signed-off-by: default avatarAustin S. Hemmelgarn <ahferroin7@gmail.com>
      Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
      88be159c
  2. Apr 28, 2016
  3. Apr 25, 2016
  4. Apr 24, 2016