The reason is:
Task1 Space balance task
do_chunk_alloc()
__finish_chunk_alloc()
update device info
in the chunk tree
alloc system metadata block
relocate system metadata block group
set system metadata block group
readonly, This block group is the
only one that can allocate space. So
there is no free space that can be
allocated now.
find no space and don't try
to alloc new chunk, and then
return ENOSPC
BUG_ON() in __finish_chunk_alloc()
was triggered.
Fix this bug by allocating a new system metadata chunk before relocating the
old one if we find there is no free space which can be allocated after setting
the old block group to be read-only.
Josef Bacik [Fri, 15 Jul 2011 21:26:38 +0000 (21:26 +0000)]
Btrfs: tag pages for writeback in sync
Everybody else does this, we need to do it too. If we're syncing, we need to
tag the pages we're going to write for writeback so we don't end up writing the
same stuff over and over again if somebody is constantly redirtying our file.
This will keep us from having latencies with heavy sync workloads. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
Josef Bacik [Fri, 15 Jul 2011 15:16:44 +0000 (15:16 +0000)]
Btrfs: fix enospc problems with delalloc
So I had this brilliant idea to use atomic counters for outstanding and reserved
extents, but this turned out to be a bad idea. Consider this where we have 1
outstanding extent and 1 reserved extent
Reserver Releaser
atomic_dec(outstanding) now 0
atomic_read(outstanding)+1 get 1
atomic_read(reserved) get 1
don't actually reserve anything because
they are the same
atomic_cmpxchg(reserved, 1, 0)
atomic_inc(outstanding)
atomic_add(0, reserved)
free reserved space for 1 extent
Then the reserver now has no actual space reserved for it, and when it goes to
finish the ordered IO it won't have enough space to do it's allocation and you
get those lovely warnings.
Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
Josef Bacik [Fri, 15 Jul 2011 16:01:03 +0000 (16:01 +0000)]
Btrfs: don't flush delalloc arbitrarily
Kill the check to see if we have 512mb of reserved space in delalloc and
shrink_delalloc if we do. This causes unexpected latencies and we have other
logic to see if we need to throttle. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
Josef Bacik [Mon, 11 Jul 2011 14:47:06 +0000 (10:47 -0400)]
Btrfs: use find_or_create_page instead of grab_cache_page
grab_cache_page will use mapping_gfp_mask(), which for all inodes is set to
GFP_HIGHUSER_MOVABLE. So instead use find_or_create_page in all cases where we
need GFP_NOFS so we don't deadlock. Thanks,
Josef Bacik [Thu, 30 Jun 2011 18:42:28 +0000 (14:42 -0400)]
Btrfs: use a worker thread to do caching
A user reported a deadlock when copying a bunch of files. This is because they
were low on memory and kthreadd got hung up trying to migrate pages for an
allocation when starting the caching kthread. The page was locked by the person
starting the caching kthread. To fix this we just need to use the async thread
stuff so that the threads are already created and we don't have to worry about
deadlocks. Thanks,
Reported-by: Roman Mamedov <rm@romanrm.ru> Signed-off-by: Josef Bacik <josef@redhat.com>
Josef Bacik [Mon, 20 Jun 2011 18:53:48 +0000 (14:53 -0400)]
Btrfs: fix how we merge extent states and deal with cached states
First, we can sometimes free the state we're merging, which means anybody who
calls merge_state() may have the state it passed in free'ed. This is
problematic because we could end up caching the state, which makes caching
useless as the state will no longer be part of the tree. So instead of free'ing
the state we passed into merge_state(), set it's end to the other->end and free
the other state. This way we are sure to cache the correct state. Also because
we can merge states together, instead of only using the cache'd state if it's
start == the start we are looking for, go ahead and use it if the start we are
looking for is within the range of the cached state. Thanks,
Josef Bacik [Fri, 10 Jun 2011 19:31:13 +0000 (15:31 -0400)]
Btrfs: use the normal checksumming infrastructure for free space cache
We used to store the checksums of the space cache directly in the space cache,
however that doesn't work out too well if we have more space than we can fit the
checksums into the first page. So instead use the normal checksumming
infrastructure. There were problems with doing this originally but those
problems don't exist now so this works out fine. Thanks,
Josef Bacik [Tue, 7 Jun 2011 20:07:44 +0000 (16:07 -0400)]
Btrfs: serialize flushers in reserve_metadata_bytes
We keep having problems with early enospc, and that's because our method of
making space is inherently racy. The problem is we can have one guy trying to
make space for himself, and in the meantime people come in and steal his
reservation. In order to stop this we make a waitqueue and put anybody who
comes into reserve_metadata_bytes on that waitqueue if somebody is trying to
make more space. Thanks,
Josef Bacik [Tue, 7 Jun 2011 19:07:51 +0000 (15:07 -0400)]
Btrfs: do transaction space reservation before joining the transaction
We have to do weird things when handling enospc in the transaction joining code.
Because we've already joined the transaction we cannot commit the transaction
within the reservation code since it will deadlock, so we have to return EAGAIN
and then make sure we don't retry too many times. Instead of doing this, just
do the reservation the normal way before we join the transaction, that way we
can do whatever we want to try and reclaim space, and then if it fails we know
for sure we are out of space and we can return ENOSPC. Thanks,
Josef Bacik [Fri, 27 May 2011 16:06:11 +0000 (12:06 -0400)]
Btrfs: try to only do one btrfs_search_slot in do_setxattr
I've been watching how many btrfs_search_slot()'s we do and I noticed that when
we create a file with selinux enabled we were doing 2 each time we initialize
the security context. That's because we lookup the xattr first so we can delete
it if we're setting a new value to an existing xattr. But in the create case we
don't have any xattrs, so it is completely useless to have the extra lookup. So
re-arrange things so that we only lookup first if we specifically have
XATTR_REPLACE. That way in the basic case we only do 1 search, and in the more
complicated case we do the normal 2 lookups. Thanks,
Josef Bacik [Sat, 2 Jul 2011 21:24:41 +0000 (21:24 +0000)]
Btrfs: don't panic if we get an error while balancing V2
A user reported an error where if we try to balance an fs after a device has
been removed it will blow up. This is because we get an EIO back and this is
where BUG_ON(ret) bites us in the ass. To fix we just exit. Thanks,
Reported-by: Anand Jain <Anand.Jain@oracle.com> Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
Miao Xie [Thu, 23 Jun 2011 07:27:13 +0000 (07:27 +0000)]
btrfs: fix inconsonant inode information
When iputting the inode, We may leave the delayed nodes if they have some
delayed items that have not been dealt with. So when the inode is read again,
we must look up the relative delayed node, and use the information in it to
initialize the inode. Or we will get inconsonant inode information, it may
cause that the same directory index number is allocated again, and hit the
following oops:
Josef Bacik [Fri, 24 Jun 2011 16:02:51 +0000 (16:02 +0000)]
Btrfs: make sure to update total_bitmaps when freeing cache V3
A user reported this bug again where we have more bitmaps than we are supposed
to. This is because we failed to load the free space cache, but don't update
the ctl->total_bitmaps counter when we remove entries from the tree. This patch
fixes this problem and we should be good to go again. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
Ilya Dryomov [Sat, 18 Jun 2011 20:26:38 +0000 (20:26 +0000)]
Btrfs: fix type mismatch in find_free_extent()
data parameter should be u64 because a full-sized chunk flags field is
passed instead of 0/1 for distinguishing data from metadata. All
underlying functions expect u64.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
Chris Mason [Fri, 17 Jun 2011 20:14:09 +0000 (16:14 -0400)]
Btrfs: avoid delayed metadata items during commits
Snapshot creation has two phases. One is the initial snapshot setup,
and the second is done during commit, while nobody is allowed to modify
the root we are snapshotting.
The delayed metadata insertion code can break that rule, it does a
delayed inode update on the inode of the parent of the snapshot,
and delayed directory item insertion.
This makes sure to run the pending delayed operations before we
record the snapshot root, which avoids corruptions.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Miao Xie [Wed, 15 Jun 2011 10:47:30 +0000 (10:47 +0000)]
btrfs: fix wrong reservation when doing delayed inode operations
We have migrated the space for the delayed inode items from
trans_block_rsv to global_block_rsv, but we forgot to set trans->block_rsv to
global_block_rsv when we doing delayed inode operations, and the following Oops
happened:
Chris Mason [Tue, 14 Jun 2011 00:00:16 +0000 (20:00 -0400)]
Btrfs: fix relocation races
The recent commit to get rid of our trans_mutex introduced
some races with block group relocation. The problem is that relocation
needs to do some record keeping about each root, and it was relying
on the transaction mutex to coordinate things in subtle ways.
This fix adds a mutex just for the relocation code and makes sure
it doesn't have a big impact on normal operations. The race is
really fixed in btrfs_record_root_in_trans, which is where we
step back and wait for the relocation code to finish accounting
setup.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Josef Bacik [Tue, 14 Jun 2011 20:22:15 +0000 (16:22 -0400)]
Btrfs: set no_trans_join after trying to expand the transaction
We can lockup if we try to allow new writers join the transaction and we have
flushoncommit set or have a pending snapshot. This is because we set
no_trans_join and then loop around and try to wait for ordered extents again.
The problem is the ordered endio stuff needs to join the transaction, which it
can't do because no_trans_join is set. So instead wait until after this loop to
set no_trans_join and then make sure to wait for num_writers == 1 in case
anybody got started in between us exiting the loop and setting no_trans_join.
This could easily be reproduced by mounting -o flushoncommit and running xfstest
13. It cannot be reproduced with this patch. Thanks,
Reported-by: Jim Schutt <jaschut@sandia.gov> Signed-off-by: Josef Bacik <josef@redhat.com>
Josef Bacik [Tue, 14 Jun 2011 19:16:14 +0000 (15:16 -0400)]
Btrfs: protect the pending_snapshots list with trans_lock
Currently there is nothing protecting the pending_snapshots list on the
transaction. We only hold the directory mutex that we are snapshotting and a
read lock on the subvol_sem, so we could race with somebody else creating a
snapshot in a different directory and end up with list corruption. So protect
this list with the trans_lock. Thanks,
Li Zefan [Wed, 8 Jun 2011 03:56:44 +0000 (03:56 +0000)]
Btrfs: use join_transaction in btrfs_evict_inode()
The WARN_ON() in start_transaction() was triggered while balancing.
The cause is btrfs_relocate_chunk() started a transaction and
then called iput() on the inode that stores free space cache,
and iput() called btrfs_start_transaction() again.
Reported-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Reviewed-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
Jan Schmidt [Wed, 4 May 2011 14:18:50 +0000 (16:18 +0200)]
Btrfs: fix extent state leak on failed nodatasum reads
When encountering an EIO while reading from a nodatasum extent, we
insert an error record into the inode's failure tree.
btrfs_readpage_end_io_hook returns early for nodatasum inodes. We'd
better clear the failure tree in that case, otherwise the kernel
complains about
BUG extent_state: Objects remaining on kmem_cache_close()
on rmmod.
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net> Signed-off-by: Chris Mason <chris.mason@oracle.com>
David Sterba [Thu, 9 Jun 2011 10:02:51 +0000 (10:02 +0000)]
btrfs: fix unlocked access of delalloc_inodes
list_splice_init will make delalloc_inodes empty, but without a spinlock
around, this may produce corrupted list head, accessed in many placess,
The race window is very tight and nobody seems to have hit it so far.
Signed-off-by: David Sterba <dsterba@suse.cz> Signed-off-by: Chris Mason <chris.mason@oracle.com>
richard kennedy [Tue, 7 Jun 2011 10:46:32 +0000 (10:46 +0000)]
btrfs: remove 64bit alignment padding to allow extent_buffer to fit into one fewer cacheline
Reorder extent_buffer to remove 8 bytes of alignment padding on 64 bit
builds. This shrinks its size to 128 bytes allowing it to fit into one
fewer cache lines and allows more objects per slab in its kmem_cache.
slabinfo extent_buffer reports :-
before:-
Sizes (bytes) Slabs
----------------------------------
Object : 136 Total : 123
SlabObj: 136 Full : 121
SlabSiz: 4096 Partial: 0
Loss : 0 CpuSlab: 2
Align : 8 Objects: 30
after :-
Object : 128 Total : 4
SlabObj: 128 Full : 2
SlabSiz: 4096 Partial: 0
Loss : 0 CpuSlab: 2
Align : 8 Objects: 32
Signed-off-by: Richard Kennedy <richard@rsk.demon.co.uk> Signed-off-by: Chris Mason <chris.mason@oracle.com>
Sage Weil [Fri, 10 Jun 2011 18:43:13 +0000 (18:43 +0000)]
Btrfs: clear current->journal_info on async transaction commit
Normally current->jouranl_info is cleared by commit_transaction. For an
async snap or subvol creation, though, it runs in a work queue. Clear
it in btrfs_commit_transaction_async() to avoid leaking a non-NULL
journal_info when we return to userspace. When the actual commit runs in
the other thread it won't care that it's current->journal_info is already
NULL.
Signed-off-by: Sage Weil <sage@newdream.net> Tested-by: Jim Schutt <jaschut@sandia.gov> Signed-off-by: Chris Mason <chris.mason@oracle.com>
Chris Mason [Fri, 10 Jun 2011 20:36:57 +0000 (16:36 -0400)]
Btrfs: make sure to recheck for bitmaps in clusters
Josef recently changed the free extent cache to look in
the block group cluster for any bitmaps before trying to
add a new bitmap for the same offset. This avoids BUG_ON()s due
covering duplicate ranges.
But it didn't go quite far enough. A given free range might span
between one or more bitmaps or free space entries. The code has
looping to cover this, but it doesn't check for clustered bitmaps
every time.
This shuffles our gotos to check for a bitmap in the cluster
for every new bitmap entry we try to add.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Arne Jansen [Fri, 10 Jun 2011 10:07:07 +0000 (12:07 +0200)]
btrfs: reinitialize scrub workers
Scrub starts the workers each time a scrub starts and stops them after it
finished. This patch adds an initialization for the workers before each
start, otherwise the workers behave strangely.
Arne Jansen [Fri, 3 Jun 2011 08:09:26 +0000 (10:09 +0200)]
btrfs: scrub: errors in tree enumeration
due to the semantics of btrfs_search_slot the path can point to an
invalid slot when ret > 0. This condition went unnoticed, which in
turn could have led to an incomplete scrubbing.
Josef Bacik [Wed, 8 Jun 2011 18:45:50 +0000 (14:45 -0400)]
Btrfs: don't map extent buffer if path->skip_locking is set
Arne's scrub stuff exposed a problem with mapping the extent buffer in
reada_for_search. He searches the commit root with multiple threads and with
skip_locking set, so we can race and overwrite node->map_token since node isn't
locked. So fix this so that we only map the extent buffer if we don't already
have a map_token and skip_locking isn't set. Without this patch scrub would
panic almost immediately, with the patch it doesn't panic anymore. Thanks,
Reported-by: Arne Jansen <sensille@gmx.net> Signed-off-by: Josef Bacik <josef@redhat.com>
Josef Bacik [Thu, 9 Jun 2011 14:15:17 +0000 (10:15 -0400)]
Btrfs: unlock the trans lock properly
In btrfs_wait_for_commit if we came upon a transaction that had committed we
just exited, but that's bad since we are holding the trans_lock. So break
instead so that the lock is dropped. Thanks,
Reported-by: David Sterba <dsterba@suse.cz> Signed-off-by: Josef Bacik <josef@redhat.com>
Josef Bacik [Wed, 8 Jun 2011 18:36:54 +0000 (14:36 -0400)]
Btrfs: don't map extent buffer if path->skip_locking is set
Arne's scrub stuff exposed a problem with mapping the extent buffer in
reada_for_search. He searches the commit root with multiple threads and with
skip_locking set, so we can race and overwrite node->map_token since node isn't
locked. So fix this so that we only map the extent buffer if we don't already
have a map_token and skip_locking isn't set. Without this patch scrub would
panic almost immediately, with the patch it doesn't panic anymore. Thanks,
Reported-by: Arne Jansen <sensille@gmx.net> Signed-off-by: Josef Bacik <josef@redhat.com>
Josef Bacik [Mon, 6 Jun 2011 14:50:35 +0000 (10:50 -0400)]
Btrfs: fix duplicate checking logic
When merging my code into the integration test the second check for duplicate
entries got screwed up. This patch fixes it by dropping ret2 and just using ret
for the return value, and checking if we got an error before adding the bitmap
to the local list. Thanks,
Josef Bacik [Fri, 27 May 2011 20:11:38 +0000 (16:11 -0400)]
Btrfs: fix the allocator loop logic
I was testing with empty_cluster = 0 to try and reproduce a problem and kept
hitting early enospc panics. This was because our loop logic was a little
confused. So this is what I did
1) Make the loop variable the ultimate decider on wether we should loop again
isntead of checking to see if we had an uncached bg, empty size or empty
cluster.
2) Increment loop before checking to see what we are on to make the loop
definitions make more sense.
3) If we are on the chunk alloc loop don't set empty_size/empty_cluster to 0
unless we didn't actually allocate a chunk. If we did allocate a chunk we
should be able to easily setup a new cluster so clearing
empty_size/empty_cluster makes us less efficient.
This kept me from hitting panics while trying to reproduce the other problem.
Thanks,
Josef Bacik [Fri, 27 May 2011 18:07:49 +0000 (14:07 -0400)]
Btrfs: fix bitmap regression
In cleaning up the clustering code I accidently introduced a regression by
adding bitmap entries to the cluster rb tree. The problem is if we've maxed out
the number of bitmaps we can have for the block group we can only add free space
to the bitmaps, but since the bitmap is on the cluster we can't find it and we
try to create another one. This would result in a panic because the total
bitmaps was bigger than the max bitmaps that were allowed. This patch fixes
this by checking to see if we have a cluster, and then looking at the cluster rb
tree to see if it has a bitmap entry and if it does and that space belongs to
that bitmap, go ahead and add it to that bitmap.
I could hit this panic every time with an fs_mark test within a couple of
minutes. With this patch I no longer hit the panic and fs_mark goes to
completion. Thanks,
Josef Bacik [Wed, 25 May 2011 17:10:16 +0000 (13:10 -0400)]
Btrfs: don't commit the transaction if we dont have enough pinned bytes
I noticed when running an enospc test that we would get stuck committing the
transaction in check_data_space even though we truly didn't have enough space.
So check to see if bytes_pinned is bigger than num_bytes, if it's not don't
commit the transaction. Thanks,
Josef Bacik [Wed, 25 May 2011 17:07:37 +0000 (13:07 -0400)]
Btrfs: noinline the cluster searching functions
When profiling the find cluster code it's hard to tell where we are spending our
time because the bitmap and non-bitmap functions get inlined by the compiler, so
make that not happen. Thanks,
Josef Bacik [Wed, 25 May 2011 17:03:16 +0000 (13:03 -0400)]
Btrfs: cache bitmaps when searching for a cluster
If we are looking for a cluster in a particularly sparse or fragmented block
group, we will do a lot of looping through the free space tree looking for
various things, and if we need to look at bitmaps we will endup doing the whole
dance twice. So instead add the bitmap entries to a temporary list so if we
have to do the bitmap search we can just look through the list of entries we've
found quickly instead of having to loop through the entire tree again. Thanks,
David Sterba [Fri, 3 Jun 2011 14:29:08 +0000 (16:29 +0200)]
btrfs: fix uninitialized variable warning
With Linus' tree, today's linux-next build (powercp ppc64_defconfig)
produced this warning:
fs/btrfs/delayed-inode.c: In function 'btrfs_delayed_update_inode':
fs/btrfs/delayed-inode.c:1598:6: warning: 'ret' may be used
uninitialized in this function
Introduced by commit 16cdcec736cd ("btrfs: implement delayed inode items
operation").
This fixes a bug in btrfs_update_inode(): if the returned value from
btrfs_delayed_update_inode is a nonzero garbage, inode stat data are not
updated and several call paths may hit a BUG_ON or fail with strange
code.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: David Sterba <dsterba@suse.cz>
David Sterba [Tue, 31 May 2011 17:08:14 +0000 (17:08 +0000)]
btrfs: use btrfs_ino to access inode number
commit 4cb5300bc ("Btrfs: add mount -o auto_defrag") accesses inode
number directly while it should use the helper with the new inode
number allocator.
Signed-off-by: David Sterba <dsterba@suse.cz> Signed-off-by: Chris Mason <chris.mason@oracle.com>
Josef Bacik [Tue, 31 May 2011 19:33:33 +0000 (19:33 +0000)]
Btrfs: don't save the inode cache if we are deleting this root
With xfstest 254 I can panic the box every time with the inode number caching
stuff on. This is because we clean the inodes out when we delete the subvolume,
but then we write out the inode cache which adds an inode to the subvolume inode
tree, and then when it gets evicted again the root gets added back on the dead
roots list and is deleted again, so we have a double free. To stop this from
happening just return 0 if refs is 0 (and we're not the tree root since tree
root always has refs of 0). With this fix 254 no longer panics. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com> Tested-by: David Sterba <dsterba@suse.cz> Signed-off-by: Chris Mason <chris.mason@oracle.com>
Arne Jansen [Mon, 30 May 2011 08:36:16 +0000 (08:36 +0000)]
btrfs: false BUG_ON when degraded
In degraded mode the struct btrfs_device of missing devs don't have
device->name set. A kstrdup of NULL correctly returns NULL. Don't
BUG in this case.
Signed-off-by: Arne Jansen <sensille@gmx.net> Signed-off-by: Chris Mason <chris.mason@oracle.com>
liubo [Wed, 1 Jun 2011 09:42:49 +0000 (09:42 +0000)]
Btrfs: don't save the inode cache in non-FS roots
This adds extra checks to make sure the inode map we are caching really
belongs to a FS root instead of a special relocation tree. It
prevents crashes during balancing operations.
Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
Chris Mason [Fri, 3 Jun 2011 05:26:53 +0000 (01:26 -0400)]
Btrfs: make sure we don't overflow the free space cache crc page
The free space cache uses only one page for crcs right now,
which means we can't have a cache file bigger than the
crcs we can fit in the first page. This adds a check to
enforce that restriction.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Arne Jansen [Sat, 28 May 2011 19:57:55 +0000 (21:57 +0200)]
btrfs: scrub: don't reuse bios and pages
The current scrub implementation reuses bios and pages as often as possible,
allocating them only on start and releasing them when finished. This leads
to more problems with the block layer than it's worth. The elevator gets
confused when there are more pages added to the bio than bi_size suggests.
This patch completely rips out the reuse of bios and pages and allocates
them freshly for each submit.
Signed-off-by: Arne Jansen <sensille@gmx.net> Signed-off-by: Chris Maosn <chris.mason@oracle.com>
Chris Mason [Fri, 27 May 2011 14:03:58 +0000 (10:03 -0400)]
Btrfs: use the device_list_mutex during write_dev_supers
write_dev_supers was changed to use RCU to protect the list of
devices, but it was then sleeping while it actually wrote the supers.
This fixes it to just use the mutex, since we really don't any
concurrency in write_dev_supers anyway.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Li Zefan [Thu, 26 May 2011 06:38:30 +0000 (06:38 +0000)]
Btrfs: setup free ino caching in a more asynchronous way
For a filesystem that has lots of files in it, the first time we mount
it with free ino caching support, it can take quite a long time to
setup the caching before we can create new files.
Here we fill the cache with [highest_ino, BTRFS_LAST_FREE_OBJECTID]
before we start the caching thread to search through the extent tree.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
Arne Jansen [Wed, 25 May 2011 12:22:50 +0000 (12:22 +0000)]
btrfs scrub: don't coalesce pages that are logically discontiguous
scrub_page collects several pages into one bio as long as they are physically
contiguous. As we only save one logical address for the whole bio, don't
collect pages that are physically contiguous but logically discontiguous.
Signed-off-by: Arne Jansen <sensille@gmx.net> Signed-off-by: Chris Mason <chris.mason@oracle.com>
Chris Mason [Tue, 24 May 2011 19:35:30 +0000 (15:35 -0400)]
Btrfs: add mount -o auto_defrag
This will detect small random writes into files and
queue the up for an auto defrag process. It isn't well suited to
database workloads yet, but works for smaller files such as rpm, sqlite
or bdb databases.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Drop device_list_mutex for the reader side on clone_fs_devices and
btrfs_rm_device pathes since the fs_info->volume_mutex can ensure the device
list is not updated
btrfs_close_extra_devices is the initialized path, we can not add or remove
device at this time, so we can simply drop the mutex safely, like other
initialized function does(add_missing_dev, __find_device, __btrfs_open_devices
...).
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
Btrfs: fix the race between reading and updating devices
On btrfs_congested_fn and __unplug_io_fn paths, we should hold
device_list_mutex to avoid remove/add device path to
update fs_devices->devices
On __btrfs_close_devices and btrfs_prepare_sprout paths, the devices in
fs_devices->devices or fs_devices->devices is updated, so we should hold
the mutex to avoid the reader side to reach them
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
merge_state can free the current state if it can be merged with the next node,
but in set_extent_bit(), after merge_state, we still use the current extent to
get the next node and cache it into cached_state
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
Julia Lawall [Sat, 14 May 2011 07:10:51 +0000 (07:10 +0000)]
fs/btrfs: Add missing btrfs_free_path
Btrfs_alloc_path should be matched with btrfs_free_path in error-handling code.
A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)
// <smpl>
@r exists@
local idexpression struct btrfs_path * x;
expression ra,rb;
position p1,p2;
@@
x = btrfs_alloc_path@p1(...)
... when != btrfs_free_path(x,...)
when != if (...) { ... btrfs_free_path(x,...) ...}
when != x = ra
if(...) { ... when != x = rb
when forall
when != btrfs_free_path(x,...)
\(return <+...x...+>; \| return@p2...; \) }
btrfs: don't spin in shrink_delalloc if there is nothing to free
Observed as a large delay when --mixed filesystem is filled up.
Test example:
1. create tiny --mixed FS:
$ dd if=/dev/zero of=2G.img seek=$((2048 * 1024 * 1024 - 1)) count=1 bs=1
$ mkfs.btrfs --mixed 2G.img
$ mount -oloop 2G.img /mnt/ut/
2. Try to fill it up:
$ dd if=/dev/urandom of=10M.file bs=10240 count=1024
$ seq 1 256 | while read file_no; do echo $file_no; time cp 10M.file ${file_no}.copy; done
Up to '200.copy' it goes fast, but when disk fills-up each -ENOSPC
message takes 3 seconds to pop-up _every_ ENOSPC (and in usermode linux
it's even more: 30-60 seconds!). (Maybe, time depends on kernel's timer resolution).
No IO, no CPU load, just rescheduling. Some debugging revealed busy spinning
in shrink_delalloc.
Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org> Reviewed-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
Hugo Mills [Sat, 14 May 2011 17:43:41 +0000 (17:43 +0000)]
btrfs: Ensure the tree search ioctl returns the right number of records
Btrfs's tree search ioctl has a field to indicate that no more than a
given number of records should be returned. The ioctl doesn't honour
this, as the tested value is not incremented until the end of the
copy_to_sk function. This patch removes an unnecessary local variable,
and updates the num_found counter as each key is found in the tree.
Signed-off-by: Hugo Mills <hugo@carfax.org.uk> Signed-off-by: Chris Mason <chris.mason@oracle.com>
Josef Bacik [Tue, 17 May 2011 13:50:54 +0000 (09:50 -0400)]
Btrfs: leave spinning on lookup and map the leaf
On lookup we only want to read the inode item, so leave the path spinning. Also
we're just wholesale reading the leaf off, so map the leaf so we don't do a
bunch of kmap/kunmaps. Thanks,
Josef Bacik [Fri, 13 May 2011 15:07:12 +0000 (11:07 -0400)]
Btrfs: don't try to allocate from a block group that doesn't have enough space
If we have a very large filesystem, we can spend a lot of time in
find_free_extent just trying to allocate from empty block groups. So instead
check to see if the block group even has enough space for the allocation, and if
not go on to the next block group.
Josef Bacik [Fri, 13 May 2011 14:32:11 +0000 (10:32 -0400)]
Btrfs: don't always do readahead
Our readahead is sort of sloppy, and really isn't always needed. For example if
ls is doing a stating ls (which is the default) it's going to stat in non-disk
order, so if say you have a directory with a stupid amount of files, readahead
is going to do nothing but waste time in the case of doing the stat. Taking the
unconditional readahead out made my test go from 57 minutes to 36 minutes. This
means that everywhere we do loop through the tree we want to make sure we do set
path->reada properly, so I went through and found all of the places where we
loop through the path and set reada to 1. Thanks,
Josef Bacik [Wed, 11 May 2011 21:30:53 +0000 (17:30 -0400)]
Btrfs: try not to sleep as much when doing slow caching
When the fs is super full and we unmount the fs, we could get stuck in this
thing where unmount is waiting for the caching kthread to make progress and the
caching kthread keeps scheduling because we're in the middle of a commit. So
instead just let the caching kthread keep going and only yeild if
need_resched(). This makes my horrible umount case go from taking up to 10
minutes to taking less than 20 seconds. Thanks,
Josef Bacik [Wed, 11 May 2011 19:26:06 +0000 (15:26 -0400)]
Btrfs: kill BTRFS_I(inode)->block_group
Originally this was going to be used as a way to give hints to the allocator,
but frankly we can get much better hints elsewhere and it's not even used at all
for anything usefull. In addition to be completely useless, when we initialize
an inode we try and find a freeish block group to set as the inodes block group,
and with a completely full 40gb fs this takes _forever_, so I imagine with say
1tb fs this is just unbearable. So just axe the thing altoghether, we don't
need it and it saves us 8 bytes in the inode and saves us 500 microseconds per
inode lookup in my testcase. Thanks,
Josef Bacik [Wed, 11 May 2011 16:25:37 +0000 (12:25 -0400)]
Btrfs: don't look at the extent buffer level 3 times in a row
We have a bit of debugging in btrfs_search_slot to make sure the level of the
cow block is the same as the original block we were cow'ing. I don't think I've
ever seen this tripped, so kill it. This saves us 2 kmap's per level in our
search. Thanks,
Josef Bacik [Wed, 11 May 2011 16:17:34 +0000 (12:17 -0400)]
Btrfs: map the node block when looking for readahead targets
If we have particularly full nodes, we could call btrfs_node_blockptr up to 32
times, which is 32 pairs of kmap/kunmap, which _sucks_. So go ahead and map the
extent buffer while we look for readahead targets. Thanks,
Josef Bacik [Wed, 4 May 2011 15:11:17 +0000 (11:11 -0400)]
Btrfs: set range_start to the right start in count_range_bits
In count_range_bits we are adjusting total_bytes based on the range we are
searching for, but we don't adjust the range start according to the range we are
searching for, which makes for weird results. For example, if the range
[0-8192]
is set DELALLOC, but I search for 4096-8192, I will get back 4096 for the number
of bytes found, but the range_start will be 0, which makes it look like the
range is [0-4096]. So instead set range_start = max(cur_start, state->start).
This makes everything come out right. Thanks,
Josef Bacik [Tue, 3 May 2011 14:40:22 +0000 (10:40 -0400)]
Btrfs: fix how we do space reservation for truncate
The ceph guys keep running into problems where we have space reserved in our
orphan block rsv when freeing it up. This is because they tend to do snapshots
alot, so their truncates tend to use a bunch of space, so when we go to do
things like update the inode we have to steal reservation space in order to make
the reservation happen. This happens because truncate can use as much space as
it freaking feels like, but we still have to hold space for removing the orphan
item and updating the inode, which will definitely always happen. So in order
to fix this we need to split all of the reservation stuf up. So with this patch
we have
1) The orphan block reserve which only holds the space for deleting our orphan
item when everything is over.
2) The truncate block reserve which gets allocated and used specifically for the
space that the truncate will use on a per truncate basis.
3) The transaction will always have 1 item's worth of data reserved so we can
update the inode normally.
Hopefully this will make the ceph problem go away. Thanks,
Josef Bacik [Mon, 11 Apr 2011 21:25:13 +0000 (17:25 -0400)]
Btrfs: kill trans_mutex
We use trans_mutex for lots of things, here's a basic list
1) To serialize trans_handles joining the currently running transaction
2) To make sure that no new trans handles are started while we are committing
3) To protect the dead_roots list and the transaction lists
Really the serializing trans_handles joining is not too hard, and can really get
bogged down in acquiring a reference to the transaction. So replace the
trans_mutex with a trans_lock spinlock and use it to do the following
1) Protect fs_info->running_transaction. All trans handles have to do is check
this, and then take a reference of the transaction and keep on going.
2) Protect the fs_info->trans_list. This doesn't get used too much, basically
it just holds the current transactions, which will usually just be the currently
committing transaction and the currently running transaction at most.
3) Protect the dead roots list. This is only ever processed by splicing the
list so this is relatively simple.
4) Protect the fs_info->reloc_ctl stuff. This is very lightweight and was using
the trans_mutex before, so this is a pretty straightforward change.
5) Protect fs_info->no_trans_join. Because we don't hold the trans_lock over
the entirety of the commit we need to have a way to block new people from
creating a new transaction while we're doing our work. So we set no_trans_join
and in join_transaction we test to see if that is set, and if it is we do a
wait_on_commit.
6) Make the transaction use count atomic so we don't need to take locks to
modify it when we're dropping references.
7) Add a commit_lock to the transaction to make sure multiple people trying to
commit the same transaction don't race and commit at the same time.
8) Make open_ioctl_trans an atomic so we don't have to take any locks for ioctl
trans.
I have tested this with xfstests, but obviously it is a pretty hairy change so
lots of testing is greatly appreciated. Thanks,
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