write_cache_pages tries to build up a large bio to stuff down the pipe.
But if it needs to wait for a page lock, it needs to make sure and send
down any pending writes so we don't deadlock with anyone who has the
page lock and is waiting for writeback of things inside the bio.
Dave Sterba triggered this as a deadlock between the autodefrag code and
the extent write_cache_pages
Signed-off-by: Chris Mason <chris.mason@oracle.com>
The tree log had two important bugs that could cause corruptions after a
crash. Sometimes we were allowing tree log blocks to be reused after
the tree log was committed but before the transaction commit was done.
This allowed a future metadata write to overwrite the tree log data. It
is fixed by adding a new variant of freeing reserved extents that always
pins them. Credit goes to Stefan Behrens and Arne Jansen for many many
hours spent tracking this bug down.
During tree log replay, we do a pass through the tree log and pin all
the extents we find. This makes sure the replay code won't go in and
use any of those blocks for new allocations during replay. The problem
is the free space cache isn't honoring these pinned extents. So the
allocator can end up handing them out, leading to all kinds of problems
during replay.
The fix here is to force any free space cache to load while we pin the
extents, and then to make sure we remove the pinned extents from the
free space rbtree.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Reported-by: Stefan Behrens <sbehrens@giantdisaster.de>
btrfs_remove_free_space needs to make sure to set ret back to a
valid return value after setting it to EAGAIN, otherwise we return
it to the callers.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
When we're doing log commits, we try to wait for more writers to come in
and make the commit bigger. This helps improve performance on rotating
disks, but on SSDs it adds latencies.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
The WARN_ON under some circumstances heavily polute log and slow down
the machine. This is just a safety, as the warning should be fixed by
another patch, nevertheless, it still pops up during testing.
Signed-off-by: David Sterba <dsterba@suse.cz>
There's a missing test whether the path passed to subvol=path option
during mount is a real subvolume, allowing any directory located in
default subovlume to be passed and accepted for mount.
(current btrfs progs prevent this early)
$ btrfs subvol snapshot . p1-snap
ERROR: '.' is not a subvolume
(with "is subvolume?" test bypassed)
$ btrfs subvol snapshot . p1-snap
Create a snapshot of '.' in './p1-snap'
$ btrfs subvol list -p .
ID 258 parent 5 top level 5 path subvol
ID 259 parent 5 top level 5 path subvol1
ID 260 parent 5 top level 5 path default-subvol1
ID 262 parent 5 top level 5 path p1/p1-snapshot
ID 263 parent 259 top level 5 path subvol1/subvol1-snap
The problem I see is that this makes a false impression of snapshotting the
given subvolume but in fact snapshots the default one: a user expects outcome
like ID 263 but in fact gets ID 262 .
This patch makes mount fail with EINVAL with a message in syslog.
Signed-off-by: David Sterba <dsterba@suse.cz>
Fix a bug introduced by 20b45077. We have to return EINVAL on mount
failure, but doing that too early in the sequence leaves all of the
devices opened exclusively. This also fixes an issue where under some
scenarios only a second mount -o degraded <devices> command would
succeed.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Initialize fs_info->bdev_holder a bit earlier to be able to pass a
correct holder id to blkdev_get() when opening seed devices with O_EXCL.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
If lookup_extent_backref fails, path->nodes[0] reasonably could be
null along with other callers of btrfs_print_leaf, so ensure we have a
valid extent buffer before dereferencing.
Signed-off-by: Daniel J Blueman <daniel.blueman@gmail.com>
The task may fail to get free space though it is enough when multi-task
space allocation and caching space happen at the same time.
Task1 Caching Thread Task2
------------------------------------------------------------------------
find_free_extent
The space has not
be cached, and start
caching thread. And
wait for it.
cache space, if
the space is > 2MB
wake up Task1
find_free_extent
get all the space that
is cached.
try to allocate space,
but there is no space
now.
trigger BUG_ON()
The message is following:
btrfs allocation failed flags 1, wanted 4096
space_info has 1040187392 free, is not full
space_info total=1082130432, used=4096, pinned=41938944, reserved=0, may_use=40828928, readonly=0
block group 12582912 has 8388608 bytes, 0 used 8388608 pinned 0 reserved
block group has cluster?: no
0 blocks of free space at or bigger than bytes is
block group 1103101952 has 1073741824 bytes, 4096 used 33550336 pinned 0 reserved
block group has cluster?: no
0 blocks of free space at or bigger than bytes is
------------[ cut here ]------------
kernel BUG at fs/btrfs/inode.c:835!
[<ffffffffa031261b>] __extent_writepage+0x1bf/0x5ce [btrfs]
[<ffffffff810cbcb8>] ? __set_page_dirty_nobuffers+0xfe/0x108
[<ffffffffa02f8ada>] ? wait_current_trans+0x23/0xec [btrfs]
[<ffffffff810c3fbf>] ? find_get_pages_tag+0x73/0xe2
[<ffffffffa0312d12>] extent_write_cache_pages.clone.0+0x176/0x29a [btrfs]
[<ffffffffa0312e74>] extent_writepages+0x3e/0x53 [btrfs]
[<ffffffff8110ad2c>] ? do_sync_write+0xc6/0x103
[<ffffffffa0302d6e>] ? btrfs_submit_direct+0x414/0x414 [btrfs]
[<ffffffff811380fa>] ? fsnotify+0x236/0x266
[<ffffffffa02fc930>] btrfs_writepages+0x22/0x24 [btrfs]
[<ffffffff810cc215>] do_writepages+0x1c/0x25
[<ffffffff810c4958>] __filemap_fdatawrite_range+0x4e/0x50
[<ffffffff810c4982>] filemap_write_and_wait_range+0x28/0x51
[<ffffffffa0306b2e>] btrfs_sync_file+0x7d/0x198 [btrfs]
[<ffffffff8110aa26>] ? fsnotify_modify+0x5d/0x65
[<ffffffff8112d150>] vfs_fsync_range+0x18/0x21
[<ffffffff8112d170>] vfs_fsync+0x17/0x19
[<ffffffff8112d316>] do_fsync+0x29/0x3e
[<ffffffff8112d348>] sys_fsync+0xb/0xf
[<ffffffff81468352>] system_call_fastpath+0x16/0x1b
[SNIP]
RIP [<ffffffffa02fe08c>] cow_file_range+0x1c4/0x32b [btrfs]
We fix this bug by trying to allocate the space again if there are block groups
in caching.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
In btrfs_get_acl(), when the second __btrfs_getxattr() call fails,
acl is not correctly set.
Therefore, a wrong value might return to the caller.
Signed-off-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Free space items are located in tree of tree roots, not in the extent
tree. It didn't pop up because lookup_free_space_inode() grabs the
inode all the time instead of actually searching the tree.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
To reproduce the bug:
# mount -o nodatacow /dev/sda7 /mnt/
# dd if=/dev/zero of=/mnt/tmp bs=4K count=1
1+0 records in
1+0 records out
4096 bytes (4.1 kB) copied, 0.000136115 s, 30.1 MB/s
# dd if=/dev/zero of=/mnt/tmp bs=4K count=1 conv=notrunc oflag=direct
dd: writing `/mnt/tmp': Input/output error
1+0 records in
0+0 records out
btrfs_ordered_update_i_size() may return 1, but btrfs_endio_direct_write()
mistakenly takes it as an error.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
It's not a big deal if we fail to allocate the array, and instead of
panic we can just give up compressing.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
We should retirn EINVAL if the start is beyond the end of the file
system in the btrfs_ioctl_fitrim(). Fix that by adding the appropriate
check for it.
Also in the btrfs_trim_fs() it is possible that len+start might overflow
if big values are passed. Fix it by decrementing the len so that start+len
is equal to the file system size in the worst case.
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
We won't defrag an extent, if it's bigger than the threshold we
specified and there's no small extent before it, but actually
the code doesn't work this way.
There are three bugs:
- When should_defrag_range() decides we should keep on defragmenting
an extent, last_len is not incremented. (old bug)
- The length that passes to should_defrag_range() is not the length
we're going to defrag. (new bug)
- We always defrag 256K bytes data, and a big extent can be part of
this range. (new bug)
For a file with 4 extents:
| 4K | 4K | 256K | 256K |
The result of defrag with (the default) 256K extent thresh should be:
| 264K | 256K |
but with those bugs, we'll get:
| 520K |
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
It's off-by-one, and thus we may skip the last page while defragmenting.
An example case:
# create /mnt/file with 2 4K file extents
# btrfs fi defrag /mnt/file
# sync
# filefrag /mnt/file
/mnt/file: 2 extents found
So it's not defragmented.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Don't use inode->i_size directly, since we're not holding i_mutex.
This also fixes another bug, that i_size can change after it's checked
against 0 and then (i_size - 1) can be negative.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Offset field in data extent backref can underflow if clone range ioctl
is used. We can reliably detect the underflow because max file size is
limited to 2^63 and max data extent size is limited by block group size.
Signed-off-by: Zheng Yan <zheng.z.yan@intel.com>
I noticed we had a little bit of latency when writing out the space cache
inodes. It's because we flush it before we write anything in case we have dirty
pages already there. This doesn't matter though since we're just going to
overwrite the space, and there really shouldn't be any dirty pages anyway. This
makes some of my tests run a little bit faster. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
Mitch kept hitting a panic because he was getting ENOSPC. One of my previous
patches makes it so we are much better at not allocating new metadata chunks.
Unfortunately coupled with the overcommit patch this works us into a bit of a
problem if we are removing a bunch of space and end up chewing up all of our
space with pinned extents. We can allocate chunks fine and overflow is ok, but
the only way to reclaim this space is to commit the transaction. So if we go to
overcommit, first check and see how much pinned space we have. If we have more
than 80% of the free space chewed up with pinned extents, just commit the
transaction, this will free up enough space for our reservation and we won't
have this problem anymore. With this patch Mitch's test doesn't blow up
anymore. Thanks,
Reported-and-tested-by: Mitch Harder <mitch.harder@sabayonlinux.org>
Signed-off-by: Josef Bacik <josef@redhat.com>
Currently btrfs_block_rsv_check does 2 things, it will either refill a block
reserve like in the truncate or refill case, or it will check to see if there is
enough space in the global reserve and possibly refill it. However because of
overcommit we could be well overcommitting ourselves just to try and refill the
global reserve, when really we should just be committing the transaction. So
breack this out into btrfs_block_rsv_refill and btrfs_block_rsv_check. Refill
will try to reserve more metadata if it can and btrfs_block_rsv_check will not,
it will only tell you if the factor of the total space is still reserved.
Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
In __unlink_start_trans() if we don't have enough room for a reservation we will
check to see if the unlink will free up space. If it does that's great, but we
will still could add an orphan item, so we need to reserve enough space to add
the orphan item. Do this and migrate the space the global reserve so it all
works out right. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
We started setting trans->block_rsv = NULL to allow the delayed refs flushing
stuff to use the right block_rsv and then just made
btrfs_trans_release_metadata() unconditionally use the trans block rsv. The
problem with this is we need to reserve some space in the transaction and then
migrate it to the global block rsv, so we need to be able to free that out
properly. So instead just move btrfs_trans_release_metadata() before the
delayed ref flushing and use trans->block_rsv for the freeing. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
Currently we only allow a maximum of 2 megabytes of pages to be flushed at a
time. This was ok before, but now we have overcommit which will screw us in a
heartbeat if we are quickly filling the disk. So instead pick either 2
megabytes or the number of pages we need to reclaim to be safe again, which ever
is larger. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
The only way we actually reclaim delalloc space is waiting for the IO to
completely finish. Usually we kick off a bunch of IO and wait for a little bit
and hope we can make our reservation, and usually this works out pretty well.
With overcommit however we can get seriously underwater if we're filling up the
disk quickly, so we need to be able to force the delalloc shrinker to wait for
the ordered IO to finish to give us a better chance of actually reclaiming
enough space to get our reservation. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
Before the only reason to commit the transaction to recover space in
reserve_metadata_bytes() was if there were enough pinned_bytes to satisfy our
reservation. But now we have the delayed inode stuff which will hold it's
reservations until we commit the transaction. So say we max out our reservation
by creating a bunch of files but don't have any pinned bytes we will ENOSPC out
early even though we could commit the transaction and get that space back. So
now just unconditionally commit the transaction since currently there is no way
to know how much metadata space is being reserved by delayed inode stuff.
Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
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: Josef Bacik <josef@redhat.com>
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: Josef Bacik <josef@redhat.com>
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: Josef Bacik <josef@redhat.com>
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: Josef Bacik <josef@redhat.com>
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: Josef Bacik <josef@redhat.com>
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: Josef Bacik <josef@redhat.com>
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: Josef Bacik <josef@redhat.com>
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: Josef Bacik <josef@redhat.com>
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: Josef Bacik <josef@redhat.com>
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: Josef Bacik <josef@redhat.com>
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: Josef Bacik <josef@redhat.com>
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: Josef Bacik <josef@redhat.com>
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: Josef Bacik <josef@redhat.com>
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
0d10ee2e6d
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: Josef Bacik <josef@redhat.com>
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: Josef Bacik <josef@redhat.com>
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: Josef Bacik <josef@redhat.com>
