1. 19 Oct, 2011 40 commits
    • Josef Bacik's avatar
      Btrfs: fix regression in re-setting a large xattr · ed3ee9f4
      Josef Bacik authored
      Recently I changed the xattr stuff to unconditionally set the xattr first in
      case the xattr didn't exist yet.  This has introduced a regression when setting
      an xattr that already exists with a large value.  If we find the key we are
      looking for split_leaf will assume that we're extending that item.  The problem
      is the size we pass down to btrfs_search_slot includes the size of the item
      already, so if we have the largest xattr we can possibly have plus the size of
      the xattr item plus the xattr item that btrfs_search_slot we'd overflow the
      leaf.  Thankfully this is not what we're doing, but split_leaf doesn't know this
      so it just returns EOVERFLOW.  So in the xattr code we need to check and see if
      we got back EOVERFLOW and treat it like EEXIST since that's really what
      happened.  Thanks,
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      ed3ee9f4
    • Josef Bacik's avatar
      Btrfs: fix the amount of space reserved for unlink · e70bea5f
      Josef Bacik authored
      Our unlink reservations were a bit much, we were reserving 10 and I only count 8
      possible items we're touching, so comment what we're reserving for and fix the
      count value.  Thanks,
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      e70bea5f
    • Josef Bacik's avatar
      Btrfs: wait for ordered extents if we didn't reclaim enough · 4b91c14f
      Josef Bacik authored
      I noticed recently that my overcommit patch was causing one of my enospc tests
      to fail 25% of the time with early ENOSPC.  This is because my overcommit patch
      was letting us go way over board, but it wasn't waiting long enough to let the
      delalloc shrinker do it's job.  The problem is we just start writeback and wait
      a little bit hoping we flush enough, but we only free up delalloc space by
      having the writes complete all the way.  We do this by waiting for ordered
      extents, which we do but only if we already free'd enough for the reservation,
      which isn't right, we should flush ordered extents if we didn't reclaim enough
      in case that will push us over the edge.  With this patch I've not seen a
      failure in this enospc test after running it in a loop for an hour.  Thanks,
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      4b91c14f
    • Josef Bacik's avatar
      Btrfs: inline checksums into the disk free space cache · 5b0e95bf
      Josef Bacik authored
      Yeah yeah I know this is how we used to do it and then I changed it, but damnit
      I'm changing it back.  The fact is that writing out checksums will modify
      metadata, which could cause us to dirty a block group we've already written out,
      so we have to truncate it and all of it's checksums and re-write it which will
      write new checksums which could dirty a blockg roup that has already been
      written and you see where I'm going with this?  This can cause unmount or really
      anything that depends on a transaction to commit to take it's sweet damned time
      to happen.  So go back to the way it was, only this time we're specifically
      setting NODATACOW because we can't go through the COW pathway anyway and we're
      doing our own built-in cow'ing by truncating the free space cache.  The other
      new thing is once we truncate the old cache and preallocate the new space, we
      don't need to do that song and dance at all for the rest of the transaction, we
      can just overwrite the existing space with the new cache if the block group
      changes for whatever reason, and the NODATACOW will let us do this fine.  So
      keep track of which transaction we last cleared our cache in and if we cleared
      it in this transaction just say we're all setup and carry on.  This survives
      xfstests and stress.sh.
      
      The inode cache will continue to use the normal csum infrastructure since it
      only gets written once and there will be no more modifications to the fs tree in
      a transaction commit.
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      5b0e95bf
    • Josef Bacik's avatar
      Btrfs: take overflow into account in reserving space · 9a82ca65
      Josef Bacik authored
      My overcommit stuff can be a little racy when we're filling up the disk with
      fs_mark and we overcommit into things that quickly get used up for data.  So use
      num_bytes to see if we have enough available space so we're less likely to
      overcommit ourselves out of the ability to make reservations.  Thanks,
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      9a82ca65
    • Josef Bacik's avatar
      Btrfs: check the return value of filemap_write_and_wait in the space cache · 549b4fdb
      Josef Bacik authored
      We need to check the return value of filemap_write_and_wait in the space cache
      writeout code.  Also don't set the inode's generation until we're sure nothing
      else is going to fail.  Thanks,
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      549b4fdb
    • Josef Bacik's avatar
      Btrfs: add a io_ctl struct and helpers for dealing with the space cache · a67509c3
      Josef Bacik authored
      In writing and reading the space cache we have one big loop that keeps track of
      which page we are on and then a bunch of sizeable loops underneath this big loop
      to try and read/write out properly.  Especially in the write case this makes
      things hugely complicated and hard to follow, and makes our error checking and
      recovery equally as complex.  So add a io_ctl struct with a bunch of helpers to
      keep track of the pages we have, where we are, if we have enough space etc.
      This unifies how we deal with the pages we're writing and keeps all the messy
      tracking internal.  This allows us to kill the big loops in both the read and
      write case and makes reviewing and chaning the write and read paths much
      simpler.  I've run xfstests and stress.sh on this code and it survives.  Thanks,
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      a67509c3
    • Josef Bacik's avatar
      Btrfs: don't skip writing out a empty block groups cache · f75b130e
      Josef Bacik authored
      I noticed a slight bug where we will not bother writing out the block group
      cache's space cache if it's space tree is empty.  Since it could have a cluster
      or pinned extents that need to be written out this is just not a valid test.
      Thanks,
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      f75b130e
    • Josef Bacik's avatar
      Btrfs: introduce mount option no_space_cache · 73bc1876
      Josef Bacik authored
      Some users have requested this and I've found I needed a way to disable cache
      loading without actually clearing the cache, so introduce the no_space_cache
      option.  Before we check the super blocks cache generation field and if it was
      populated we always turned space caching on.  Now we check this and set the
      space cache option on, and then parse the mount options so that if we want it
      off it get's turned off.  Then we check the mount option all the places we do
      the caching work instead of checking the super's cache generation.  This makes
      things more consistent and lets us turn space caching off.  Thanks,
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      73bc1876
    • Josef Bacik's avatar
      Btrfs: only inherit btrfs specific flags when creating files · e27425d6
      Josef Bacik authored
      Xfstests 79 was failing because we were inheriting the S_APPEND flag when we
      weren't supposed to.  There isn't any specific documentation on this so I'm
      taking the test as the standard of how things work, and having S_APPEND set on a
      directory doesn't mean that S_APPEND gets inherited by its children according to
      this test.  So only inherit btrfs specific things.  This will let us set
      compress/nocompress on specific directories and everything in the directories
      will inherit this flag, same with nodatacow.  With this patch test 79 passes.
      Thanks,
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      e27425d6
    • Josef Bacik's avatar
      Btrfs: allow us to overcommit our enospc reservations · 2bf64758
      Josef Bacik authored
      One of the things that kills us is the fact that our ENOSPC reservations are
      horribly over the top in most normal cases.  There isn't too much that can be
      done about this because when we are completely full we really need them to work
      like this so we don't under reserve.  However if there is plenty of unallocated
      chunks on the disk we can use that to gauge how much we can overcommit.  So this
      patch adds chunk free space accounting so we always know how much unallocated
      space we have.  Then if we fail to make a reservation within our allocated
      space, check to see if we can overcommit.  In the normal flushing case (like
      with delalloc metadata reservations) we'll take the free space and divide it by
      2 if our metadata profile is setup for DUP or any of those, and then divide it
      by 8 to make sure we don't overcommit too much.  Then if we're in a non-flushing
      case (we really need this reservation now!) we only limit ourselves to half of
      the free space.  This makes this fio test
      
      [torrent]
      filename=torrent-test
      rw=randwrite
      size=4g
      ioengine=sync
      directory=/mnt/btrfs-test
      
      go from taking around 45 minutes to 10 seconds on my freshly formatted 3 TiB
      file system.  This doesn't seem to break my other enospc tests, but could really
      use some more testing as this is a super scary change.  Thanks,
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      2bf64758
    • Josef Bacik's avatar
      Btrfs: break out of orphan cleanup if we can't make progress · 8f6d7f4f
      Josef Bacik authored
      I noticed while running xfstests 83 that if we didn't have enough space to
      delete our inode the orphan cleanup would just loop.  This is because it keeps
      finding the same orphan item and keeps trying to kill it but can't because we
      don't get an error back from iput for deleting the inode.  So keep track of the
      last guy we tried to kill, if it's the same as the one we're trying to kill
      currently we know we are having problems and can just error out.  I don't have a
      way to test this so look hard and make sure it's right.  Thanks,
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      8f6d7f4f
    • Josef Bacik's avatar
      Btrfs: use the global reserve as a backup for deleting inodes · 726c35fa
      Josef Bacik authored
      Xfstests 83 really stresses our ENOSPC since it uses a 100mb fs which ends up
      with the mixed block group stuff.  Because of this we can run into a situation
      where we don't have enough space to delete inodes, or even worse we can't free
      the inodes when we next mount the fs which causes the orphan code to lose its
      mind.  So if we fail to make our reservation, steal from the global reserve.
      The global reserve will end up taking up the entire rest of the free space on
      the fs in this worst case so there really is no other option.  With this patch
      test 83 doesn't freak out.  Thanks,
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      726c35fa
    • Josef Bacik's avatar
      Btrfs: stop using write_one_page · 1728366e
      Josef Bacik authored
      While looking for a performance regression a user was complaining about, I
      noticed that we had a regression with the varmail test of filebench.  This was
      introduced by
      
      0d10ee2e
      
      which keeps us from calling writepages in writepage.  This is a correct change,
      however it happens to help the varmail test because we write out in larger
      chunks.  This is largly to do with how we write out dirty pages for each
      transaction.  If you run filebench with
      
      load varmail
      set $dir=/mnt/btrfs-test
      run 60
      
      prior to this patch you would get ~1420 ops/second, but with the patch you get
      ~1200 ops/second.  This is a 16% decrease.  So since we know the range of dirty
      pages we want to write out, don't write out in one page chunks, write out in
      ranges.  So to do this we call filemap_fdatawrite_range() on the range of bytes.
      Then we convert the DIRTY extents to NEED_WAIT extents.  When we then call
      btrfs_wait_marked_extents() we only have to filemap_fdatawait_range() on that
      range and clear the NEED_WAIT extents.  This doesn't get us back to our original
      speeds, but I've been seeing ~1380 ops/second, which is a <5% regression as
      opposed to a >15% regression.  That is acceptable given that the original commit
      greatly reduces our latency to begin with.  Thanks,
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      1728366e
    • Josef Bacik's avatar
      Btrfs: introduce convert_extent_bit · 462d6fac
      Josef Bacik authored
      If I have a range where I know a certain bit is and I want to set it to another
      bit the only option I have is to call set and then clear bit, which will result
      in 2 tree searches.  This is inefficient, so introduce convert_extent_bit which
      will go through and set the bit I want and clear the old bit I don't want.
      Thanks,
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      462d6fac
    • Josef Bacik's avatar
      Btrfs: check unused against how much space we actually want · ef3be457
      Josef Bacik authored
      There is a bug that may lead to early ENOSPC in our reservation code.  We've
      been checking against num_bytes which may be above and beyond what we want to
      actually reserve, which could give us a false ENOSPC.  Fix this by making sure
      the unused space is above how much we want to reserve and not how much we're
      trying to flush.  Thanks,
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      ef3be457
    • Josef Bacik's avatar
      Btrfs: fix orphan cleanup regression · a8c9e576
      Josef Bacik authored
      In fixing how we deal with bad inodes, we had a regression in the orphan cleanup
      code, since it expects to get a bad inode back.  So fix it to deal with getting
      -ESTALE back by deleting the orphan item manually and moving on.  Thanks,
      Reported-by: default avatarSimon Kirby <sim@hostway.ca>
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      a8c9e576
    • Josef Bacik's avatar
      Btrfs: use the inode's mapping mask for allocating pages · 3b16a4e3
      Josef Bacik authored
      Johannes pointed out we were allocating only kernel pages for doing writes,
      which is kind of a big deal if you are on 32bit and have more than a gig of ram.
      So fix our allocations to use the mapping's gfp but still clear __GFP_FS so we
      don't re-enter.  Thanks,
      Reported-by: default avatarJohannes Weiner <jweiner@redhat.com>
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      3b16a4e3
    • Josef Bacik's avatar
      Btrfs: delay iput when deleting a block group · 455757c3
      Josef Bacik authored
      I kept getting warnings from evict because we were calling
      btrfs_start_transaction() with a transaction already started when doing a
      balance.  This is because we remove a block group which requires a transaction,
      and the put the last reference on the cache inode.  Instead of doing this we
      need to delay the iput so it is done not within a transaction having started.
      This gets rid of our warnings.  Thanks,
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      455757c3
    • Josef Bacik's avatar
      Btrfs: make sure to unset trans->block_rsv before running delayed refs · 9c8d86db
      Josef Bacik authored
      Checksums are charged in 2 different ways.  The first case is when we're writing
      to the disk, we account for the new checksums with the delalloc block rsv.  In
      order for this to work we check if we're allocating a block for the csum root
      and if trans->block_rsv == the delalloc block rsv.  But when we're deleting the
      csums because of cow, this is charged to the global block rsv, and is done when
      we run the delayed refs.  So we need to make sure that trans->block_rsv == NULL
      when running the delayed refs.  So set it to NULL and reset it in
      should_end_transaction, and set it to NULL in commit_transaction.  This got rid
      of the ridiculous amount of warnings I was seeing when trying to do a balance.
      Thanks,
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      9c8d86db
    • Josef Bacik's avatar
      Btrfs: stop passing a trans handle all around the reservation code · 4a92b1b8
      Josef Bacik authored
      The only thing that we need to have a trans handle for is in
      reserve_metadata_bytes and thats to know how much flushing we can do.  So
      instead of passing it around, just check current->journal_info for a
      trans_handle so we know if we can commit a transaction to try and free up space
      or not.  Thanks,
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      4a92b1b8
    • Josef Bacik's avatar
      Btrfs: don't get the block_rsv in btrfs_free_tree_block · d02c9955
      Josef Bacik authored
      Since the durable block rsv stuff has been killed there is no need to get the
      block_rsv in btrfs_free_tree_block anymore.
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      d02c9955
    • Josef Bacik's avatar
      Btrfs: use the transactions block_rsv for the csum root · 4c13d758
      Josef Bacik authored
      The alloc warnings everybody has been seeing is because we have been reserving
      space for csums, but we weren't actually using that space.  So make
      get_block_rsv() return the trans->block_rsv if we're modifying the csum root.
      Also set the trans->block_rsv to NULL so that if we modify the csum root when
      running delayed ref's that comes out of the global reserve like it's supposed
      to.  With this patch I'm not seeing those alloc warnings anymore.  Thanks,
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      4c13d758
    • Josef Bacik's avatar
      Btrfs: handle enospc accounting for free space inodes · c09544e0
      Josef Bacik authored
      Since free space inodes now use normal checksumming we need to make sure to
      account for their metadata use.  So reserve metadata space, and then if we fail
      to write out the metadata we can just release it, otherwise it will be freed up
      when the io completes.  Thanks,
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      c09544e0
    • Josef Bacik's avatar
      Btrfs: put the block group cache after we commit the super · 300e4f8a
      Josef Bacik authored
      In moving some enospc stuff around I noticed that when we unmount we are often
      evicting the free space cache inodes before we do our last commit.  This isn't
      bad, but it makes us constantly have to re-read the inodes back.  So instead
      don't evict the cache until after we do our last commit, this will make things a
      little less crappy and makes a future enospc change work properly.  Thanks,
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      300e4f8a
    • Josef Bacik's avatar
      Btrfs: set truncate block rsv's size · 4a338542
      Josef Bacik authored
      While debugging a different issue I noticed that we were always reserving space
      when we tried to use our truncate block rsv's.  This is because they didn't have
      a ->size value, so use_block_rsv just assumes there is nothing reserved and it
      does a reserve_metadata_bytes.  This is because btrfs_check_block_rsv() doesn't
      actually add to the size of the block rsv.  That seems to be the right thing to
      do so set ->size to the minimum truncate size we need, since we will always only
      refill to that size anyway, and this way everything works out correctly.
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      4a338542
    • Josef Bacik's avatar
      Btrfs: don't increase the block_rsv's size when emergency allocating space · 7f701508
      Josef Bacik authored
      If we have to emergency reserve space we need to not increase the block_rsv
      size, otherwise we'll leak space.  Take for instance delalloc, say we reserve
      4k, and we use that 4k, and then we have to emergency allocate another 4k, we
      bump the size up to 8k, however we've only accounted for 4k in reservations in
      all of our supporting logic, so we'll go to free the 4k and end up having a size
      of 4k, which will cause us to later not free as much space.  I saw this doing
      testing where I wasn't reserving enough space for something but was still
      leaking space, very frustrating.  Thanks,
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      7f701508
    • Josef Bacik's avatar
      Btrfs: fix space leak when we fail to make an allocation · 7ed49f18
      Josef Bacik authored
      When changing back to using a spin_lock to protect the extent counters I decided
      that since we would only be dropping our original extent, it was ok to just drop
      the extent and return.  However since somebody else could have come in and done
      a reservation, we need to do the normal song and dance to clear the reservation
      out properly.  So calculate how much space we need to free, and then subtract
      what we just attempted to reserve.  If it's more then we know we need to drop
      those bytes from the delalloc block rsv.  Thanks,
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      7ed49f18
    • Josef Bacik's avatar
      Btrfs: fix call to btrfs_search_slot in free space cache · a9b5fcdd
      Josef Bacik authored
      We are setting ins_len to 1 even tho we are just modifying an item that should
      be there already.  This may cause the search stuff to split nodes on the way
      down needelessly.  Set this to 0 since we aren't inserting anything.  Thanks,
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      a9b5fcdd
    • Josef Bacik's avatar
      Btrfs: allow callers to specify if flushing can occur for btrfs_block_rsv_check · 482e6dc5
      Josef Bacik authored
      If you run xfstest 224 it you will get lots of messages about not being able to
      delete inodes and that they will be cleaned up next mount.  This is because
      btrfs_block_rsv_check was not calling reserve_metadata_bytes with the ability to
      flush, so if there was not enough space, it simply failed.  But in truncate and
      evict case we could easily flush space to try and get enough space to do our
      work, so make btrfs_block_rsv_check take a flush argument to pass down to
      reserve_metadata_bytes.  Now xfstests 224 runs fine without all those
      complaints.  Thanks,
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      482e6dc5
    • Josef Bacik's avatar
      Btrfs: reduce the amount of space needed for truncates · 07127184
      Josef Bacik authored
      With btrfs_truncate_inode_items we always return if we have to go to another
      leaf, which makes us do our reservation again.  This means we will only ever
      modify one leaf at a time, so we only need 1 items worth of slack space.  Also,
      since we are deleting we will not be creating nodes as we go down, if anything
      we'll be free'ing them as we merge them together, so make a different
      calculation for truncate which will only have the worst case useage of COW'ing
      the entire path down to the leaf.  Thanks,
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      07127184
    • Josef Bacik's avatar
      Btrfs: only reserve space in fallocate if we have to do a preallocate · 1b9c332b
      Josef Bacik authored
      Lukas found a problem where if he tries to fallocate over the same region twice
      and the first fallocate took up all the space we would fail with ENOSPC.  This
      is because we reserve the total space we want to use for fallocate, regardless
      of wether or not we will have to actually preallocate.  So instead move the
      check into the loop where we actually have to do the preallocate.  Thanks,
      Tested-by: default avatarLukas Czerner <lczerner@redhat.com>
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      1b9c332b
    • Josef Bacik's avatar
      Btrfs: kill btrfs_truncate_reserve_metadata · 5e962c78
      Josef Bacik authored
      Since we've optimized the truncate path, we no longer require this function.
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      5e962c78
    • Josef Bacik's avatar
      Btrfs: optimize how we account for space in truncate · 907cbceb
      Josef Bacik authored
      Currently we're starting and stopping a transaction for no real reason, so kill
      that and just reserve enough space as if we can truncate all in one transaction.
      Also use btrfs_block_rsv_check() for our reserve to minimize the amount of space
      we may have to allocate for our slack space.  Thanks,
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      907cbceb
    • Josef Bacik's avatar
      Btrfs: don't try to commit in btrfs_block_rsv_check · 13553e52
      Josef Bacik authored
      We will try and reserve metadata bytes in btrfs_block_rsv_check and if we cannot
      because we have a transaction open it will return EAGAIN, so we do not need to
      try and commit the transaction again.
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      13553e52
    • Josef Bacik's avatar
      Btrfs: kill unused parts of block_rsv · dabdb640
      Josef Bacik authored
      The priority and refill_used flags are not used anymore, and neither is the
      usage counter, so just remove them from btrfs_block_rsv.
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      dabdb640
    • Josef Bacik's avatar
      Btrfs: ratelimit the generation printk for the free space cache · 6ab60601
      Josef Bacik authored
      A user reported getting spammed when moving to 3.0 by this message.  Since we
      switched to the normal checksumming infrastructure all old free space caches
      will be wrong and need to be regenerated so people are likely to see this
      message a lot, so ratelimit it so it doesn't fill up their logs and freak them
      out.  Thanks,
      Reported-by: default avatarAndrew Lutomirski <luto@mit.edu>
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      6ab60601
    • Josef Bacik's avatar
      Btrfs: fix how we reserve space for deleting inodes · 4289a667
      Josef Bacik authored
      I converted btrfs_truncate to do sane reservations for truncate, but didn't
      convert btrfs_evict_inode.  Basically we need to save the orphan_rsv for
      deleting the orphan item, and do normal reservations for our truncate.  Thanks,
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      4289a667
    • Josef Bacik's avatar
      Btrfs: kill the durable block rsv stuff · 37be25bc
      Josef Bacik authored
      This is confusing code and isn't used by anything anymore, so delete it.
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      37be25bc
    • Josef Bacik's avatar
      Btrfs: kill the orphan space calculation for snapshots · dba68306
      Josef Bacik authored
      This patch kills off the calculation for the amount of space needed for the
      orphan operations during a snapshot.  The thing is we only do snapshots on
      commit, so any space that is in the block_rsv->freed[] isn't going to be in the
      new snapshot anyway, so there isn't any reason to require that space to be
      reserved for the snapshot to occur.  Thanks,
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      dba68306