Hit this nice little deadlock.  What happens is this

__btrfs_end_transaction with throttle set, --use_count so it equals 0
  btrfs_commit_transaction
    <somebody else actually manages to start the commit>
    btrfs_end_transaction --use_count so now its -1 <== BAD
      we just return and wait on the transaction

This is bad because we just return after our use_count is -1 and don't let go
of our num_writer count on the transaction, so the guy committing the
transaction just sits there forever.  Fix this by inc'ing our use_count if we're
going to call commit_transaction so that if we call btrfs_end_transaction it's
valid.  Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

The extent_buffers have a very complex interface where
we use HIGHMEM for metadata and try to cache a kmap mapping
to access the memory.

The next commit adds reader/writer locks, and concurrent use
of this kmap cache would make it even more complex.

This commit drops the ability to use HIGHMEM with extent buffers,
and rips out all of the related code.
Signed-off-by: Chris Mason <chris.mason@oracle.com>

When we balanced the chunks across the devices, BUG_ON() in
__finish_chunk_alloc() was triggered.

------------[ cut here ]------------
kernel BUG at fs/btrfs/volumes.c:2568!
[SNIP]
Call Trace:
 [<ffffffffa049525e>] btrfs_alloc_chunk+0x8e/0xa0 [btrfs]
 [<ffffffffa04546b0>] do_chunk_alloc+0x330/0x3a0 [btrfs]
 [<ffffffffa045c654>] btrfs_reserve_extent+0xb4/0x1f0 [btrfs]
 [<ffffffffa045c86b>] btrfs_alloc_free_block+0xdb/0x350 [btrfs]
 [<ffffffffa048a8d8>] ? read_extent_buffer+0xd8/0x1d0 [btrfs]
 [<ffffffffa04476fd>] __btrfs_cow_block+0x14d/0x5e0 [btrfs]
 [<ffffffffa044660d>] ? read_block_for_search+0x14d/0x4d0 [btrfs]
 [<ffffffffa0447c9b>] btrfs_cow_block+0x10b/0x240 [btrfs]
 [<ffffffffa044dd5e>] btrfs_search_slot+0x49e/0x7a0 [btrfs]
 [<ffffffffa044f07d>] btrfs_insert_empty_items+0x8d/0xf0 [btrfs]
 [<ffffffffa045e973>] insert_with_overflow+0x43/0x110 [btrfs]
 [<ffffffffa045eb0d>] btrfs_insert_dir_item+0xcd/0x1f0 [btrfs]
 [<ffffffffa0489bd0>] ? map_extent_buffer+0xb0/0xc0 [btrfs]
 [<ffffffff812276ad>] ? rb_insert_color+0x9d/0x160
 [<ffffffffa046cc40>] ? inode_tree_add+0xf0/0x150 [btrfs]
 [<ffffffffa0474801>] btrfs_add_link+0xc1/0x1c0 [btrfs]
 [<ffffffff811dacac>] ? security_inode_init_security+0x1c/0x30
 [<ffffffffa04a28aa>] ? btrfs_init_acl+0x4a/0x180 [btrfs]
 [<ffffffffa047492f>] btrfs_add_nondir+0x2f/0x70 [btrfs]
 [<ffffffffa046af16>] ? btrfs_init_inode_security+0x46/0x60 [btrfs]
 [<ffffffffa0474ac0>] btrfs_create+0x150/0x1d0 [btrfs]
 [<ffffffff81159c63>] ? generic_permission+0x23/0xb0
 [<ffffffff8115b415>] vfs_create+0xa5/0xc0
 [<ffffffff8115ce6e>] do_last+0x5fe/0x880
 [<ffffffff8115dc0d>] path_openat+0xcd/0x3d0
 [<ffffffff8115e029>] do_filp_open+0x49/0xa0
 [<ffffffff8116a965>] ? alloc_fd+0x95/0x160
 [<ffffffff8114f0c7>] do_sys_open+0x107/0x1e0
 [<ffffffff810bcc3f>] ? audit_syscall_entry+0x1bf/0x1f0
 [<ffffffff8114f1e0>] sys_open+0x20/0x30
 [<ffffffff81484ec2>] system_call_fastpath+0x16/0x1b
[SNIP]
RIP  [<ffffffffa049444a>] __finish_chunk_alloc+0x20a/0x220 [btrfs]

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.
Reported-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Tested-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

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>

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>

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>

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,
Signed-off-by: Josef Bacik <josef@redhat.com>

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>

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,
Signed-off-by: Josef Bacik <josef@redhat.com>

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,
Signed-off-by: Josef Bacik <josef@redhat.com>

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,
Signed-off-by: Josef Bacik <josef@redhat.com>

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,
Signed-off-by: Josef Bacik <josef@redhat.com>

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,
Signed-off-by: Josef Bacik <josef@redhat.com>

We need to make sure the data relocation inode doesn't go through
the delayed metadata updates, otherwise we get an oops during balance:

kernel BUG at fs/btrfs/relocation.c:4303!
[SNIP]
Call Trace:
 [<ffffffffa03143fd>] ? update_ref_for_cow+0x22d/0x330 [btrfs]
 [<ffffffffa0314951>] __btrfs_cow_block+0x451/0x5e0 [btrfs]
 [<ffffffffa031355d>] ? read_block_for_search+0x14d/0x4d0 [btrfs]
 [<ffffffffa0314beb>] btrfs_cow_block+0x10b/0x240 [btrfs]
 [<ffffffffa031acae>] btrfs_search_slot+0x49e/0x7a0 [btrfs]
 [<ffffffffa032d8af>] btrfs_lookup_inode+0x2f/0xa0 [btrfs]
 [<ffffffff8147bf0e>] ? mutex_lock+0x1e/0x50
 [<ffffffffa0380cf1>] btrfs_update_delayed_inode+0x71/0x160 [btrfs]
 [<ffffffffa037ff27>] ? __btrfs_release_delayed_node+0x67/0x190 [btrfs]
 [<ffffffffa0381cf8>] btrfs_run_delayed_items+0xe8/0x120 [btrfs]
 [<ffffffffa03365e0>] btrfs_commit_transaction+0x250/0x850 [btrfs]
 [<ffffffff810f91d9>] ? find_get_pages+0x39/0x130
 [<ffffffffa0336cd5>] ? join_transaction+0x25/0x250 [btrfs]
 [<ffffffff81081de0>] ? wake_up_bit+0x40/0x40
 [<ffffffffa03785fa>] prepare_to_relocate+0xda/0xf0 [btrfs]
 [<ffffffffa037f2bb>] relocate_block_group+0x4b/0x620 [btrfs]
 [<ffffffffa0334cf5>] ? btrfs_clean_old_snapshots+0x35/0x150 [btrfs]
 [<ffffffffa037fa43>] btrfs_relocate_block_group+0x1b3/0x2e0 [btrfs]
 [<ffffffffa0368ec0>] ? btrfs_tree_unlock+0x50/0x50 [btrfs]
 [<ffffffffa035e39b>] btrfs_relocate_chunk+0x8b/0x670 [btrfs]
 [<ffffffffa031303d>] ? btrfs_set_path_blocking+0x3d/0x50 [btrfs]
 [<ffffffffa03577d8>] ? read_extent_buffer+0xd8/0x1d0 [btrfs]
 [<ffffffffa031bea1>] ? btrfs_previous_item+0xb1/0x150 [btrfs]
 [<ffffffffa03577d8>] ? read_extent_buffer+0xd8/0x1d0 [btrfs]
 [<ffffffffa035f5aa>] btrfs_balance+0x21a/0x2b0 [btrfs]
 [<ffffffffa0368898>] btrfs_ioctl+0x798/0xd20 [btrfs]
 [<ffffffff8111e358>] ? handle_mm_fault+0x148/0x270
 [<ffffffff814809e8>] ? do_page_fault+0x1d8/0x4b0
 [<ffffffff81160d6a>] do_vfs_ioctl+0x9a/0x540
 [<ffffffff811612b1>] sys_ioctl+0xa1/0xb0
 [<ffffffff81484ec2>] system_call_fastpath+0x16/0x1b
[SNIP]
RIP  [<ffffffffa037c1cc>] btrfs_reloc_cow_block+0x22c/0x270 [btrfs]
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

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>

There are three missed mount options settable by user which are not
currently displayed in mount output.
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

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:

[ 5447.554187] err add delayed dir index item(name: pglog_0.965_0) into the
insertion tree of the delayed node(root id: 262, inode id: 258, errno: -17)
[ 5447.569766] ------------[ cut here ]------------
[ 5447.575361] kernel BUG at fs/btrfs/delayed-inode.c:1301!
[SNIP]
[ 5447.790721] Call Trace:
[ 5447.793191]  [<ffffffffa0641c4e>] btrfs_insert_dir_item+0x189/0x1bb [btrfs]
[ 5447.800156]  [<ffffffffa0651a45>] btrfs_add_link+0x12b/0x191 [btrfs]
[ 5447.806517]  [<ffffffffa0651adc>] btrfs_add_nondir+0x31/0x58 [btrfs]
[ 5447.812876]  [<ffffffffa0651d6a>] btrfs_create+0xf9/0x197 [btrfs]
[ 5447.818961]  [<ffffffff8111f840>] vfs_create+0x72/0x92
[ 5447.824090]  [<ffffffff8111fa8c>] do_last+0x22c/0x40b
[ 5447.829133]  [<ffffffff8112076a>] path_openat+0xc0/0x2ef
[ 5447.834438]  [<ffffffff810c58e2>] ? __perf_event_task_sched_out+0x24/0x44
[ 5447.841216]  [<ffffffff8103ecdd>] ? perf_event_task_sched_out+0x59/0x67
[ 5447.847846]  [<ffffffff81121a79>] do_filp_open+0x3d/0x87
[ 5447.853156]  [<ffffffff811e126c>] ? strncpy_from_user+0x43/0x4d
[ 5447.859072]  [<ffffffff8111f1f5>] ? getname_flags+0x2e/0x80
[ 5447.864636]  [<ffffffff8111f179>] ? do_getname+0x14b/0x173
[ 5447.870112]  [<ffffffff8111f1b7>] ? audit_getname+0x16/0x26
[ 5447.875682]  [<ffffffff8112b1ab>] ? spin_lock+0xe/0x10
[ 5447.880882]  [<ffffffff81112d39>] do_sys_open+0x69/0xae
[ 5447.886153]  [<ffffffff81112db1>] sys_open+0x20/0x22
[ 5447.891114]  [<ffffffff813b9aab>] system_call_fastpath+0x16/0x1b

Fix it by reusing the old delayed node.
Reported-by: Jim Schutt <jaschut@sandia.gov>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Tested-by: Jim Schutt <jaschut@sandia.gov>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

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>

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>

When we create a new inode, we aren't filling in the
field that records the transaction that last changed this
inode.

If we then go to fsync that inode, it will be skipped because the field
isn't filled in.
Signed-off-by: Chris Mason <chris.mason@oracle.com>

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>

When allocation fails in btrfs_read_fs_root_no_name, ret is not set
although it is returned, holding a garbage value.
Signed-off-by: David Sterba <dsterba@suse.cz>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

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:

[ 9792.654889] ------------[ cut here ]------------
[ 9792.654898] WARNING: at fs/btrfs/extent-tree.c:5681
btrfs_alloc_free_block+0xca/0x27c [btrfs]()
[ 9792.654899] Hardware name: To Be Filled By O.E.M.
[ 9792.654900] Modules linked in: btrfs zlib_deflate libcrc32c
ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 ip6table_filter ip6_tables
arc4 rt61pci rt2x00pci rt2x00lib snd_hda_codec_hdmi mac80211
snd_hda_codec_realtek cfg80211 snd_hda_intel edac_core snd_seq rfkill
pcspkr serio_raw snd_hda_codec eeprom_93cx6 edac_mce_amd sp5100_tco
i2c_piix4 k10temp snd_hwdep snd_seq_device snd_pcm floppy r8169 xhci_hcd
mii snd_timer snd soundcore snd_page_alloc ipv6 firewire_ohci pata_acpi
ata_generic firewire_core pata_via crc_itu_t radeon ttm drm_kms_helper
drm i2c_algo_bit i2c_core [last unloaded: scsi_wait_scan]
[ 9792.654919] Pid: 2762, comm: rm Tainted: G        W   2.6.39+ #1
[ 9792.654920] Call Trace:
[ 9792.654922]  [<ffffffff81053c4a>] warn_slowpath_common+0x83/0x9b
[ 9792.654925]  [<ffffffff81053c7c>] warn_slowpath_null+0x1a/0x1c
[ 9792.654933]  [<ffffffffa038e747>] btrfs_alloc_free_block+0xca/0x27c [btrfs]
[ 9792.654945]  [<ffffffffa03b8562>] ? map_extent_buffer+0x6e/0xa8 [btrfs]
[ 9792.654953]  [<ffffffffa038189b>] __btrfs_cow_block+0xfc/0x30c [btrfs]
[ 9792.654963]  [<ffffffffa0396aa6>] ? btrfs_buffer_uptodate+0x47/0x58 [btrfs]
[ 9792.654970]  [<ffffffffa0382e48>] ? read_block_for_search+0x94/0x368 [btrfs]
[ 9792.654978]  [<ffffffffa0381ba9>] btrfs_cow_block+0xfe/0x146 [btrfs]
[ 9792.654986]  [<ffffffffa03848b0>] btrfs_search_slot+0x14d/0x4b6 [btrfs]
[ 9792.654997]  [<ffffffffa03b8562>] ? map_extent_buffer+0x6e/0xa8 [btrfs]
[ 9792.655022]  [<ffffffffa03938e8>] btrfs_lookup_inode+0x2f/0x8f [btrfs]
[ 9792.655025]  [<ffffffff8147afac>] ? _cond_resched+0xe/0x22
[ 9792.655027]  [<ffffffff8147b892>] ? mutex_lock+0x29/0x50
[ 9792.655039]  [<ffffffffa03d41b1>] btrfs_update_delayed_inode+0x72/0x137 [btrfs]
[ 9792.655051]  [<ffffffffa03d4ea2>] btrfs_run_delayed_items+0x90/0xdb [btrfs]
[ 9792.655062]  [<ffffffffa039a69b>] btrfs_commit_transaction+0x228/0x654 [btrfs]
[ 9792.655064]  [<ffffffff8106e8da>] ? remove_wait_queue+0x3a/0x3a
[ 9792.655075]  [<ffffffffa03a2fa5>] btrfs_evict_inode+0x14d/0x202 [btrfs]
[ 9792.655077]  [<ffffffff81132bd6>] evict+0x71/0x111
[ 9792.655079]  [<ffffffff81132de0>] iput+0x12a/0x132
[ 9792.655081]  [<ffffffff8112aa3a>] do_unlinkat+0x106/0x155
[ 9792.655083]  [<ffffffff81127b83>] ? path_put+0x1f/0x23
[ 9792.655085]  [<ffffffff8109c53c>] ? audit_syscall_entry+0x145/0x171
[ 9792.655087]  [<ffffffff81128410>] ? putname+0x34/0x36
[ 9792.655090]  [<ffffffff8112b441>] sys_unlinkat+0x29/0x2b
[ 9792.655092]  [<ffffffff81482c42>] system_call_fastpath+0x16/0x1b
[ 9792.655093] ---[ end trace 02b696eb02b3f768 ]---

This patch fix it by setting the reservation of the transaction handle to the
correct one.
Reported-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

Removes code no longer used. The sysfs file itself is kept, because the
btrfs developers expressed interest in putting new entries to sysfs.
Signed-off-by: Maarten Lankhorst <m.b.lankhorst@gmail.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

smatch reports:

btrfs_recover_log_trees error: 'wc.replay_dest' dereferencing
possible ERR_PTR()
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

Merge branch 'for-chris' of git://git.kernel.org/pub/scm/linux/kernel/git/josef/btrfs-work into for-linus

Conflicts:
	fs/btrfs/transaction.c
Signed-off-by: Chris Mason <chris.mason@oracle.com>

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>

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>

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,
Signed-off-by: Josef Bacik <josef@redhat.com>

The delayed ref patch accidently removed the btrfs_free_path in
btrfs_unlink_subvol, this puts it back and means we don't leak a path.  Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>

Even when delalloc_bytes is zero, we may need to sleep while waiting
for delalloc space.
Signed-off-by: Chris Mason <chris.mason@oracle.com>

Al Viro noticed we weren't checking for set_anon_super failures.  This
adds the required checks.
Signed-off-by: Chris Mason <chris.mason@oracle.com>

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>

Get rid of FIXME comment.  Uuids from dmesg are now the same as uuids
given by btrfs-progs.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

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>

Merge branch 'for-chris' of git://git.kernel.org/pub/scm/linux/kernel/git/arne/btrfs-unstable-arne into for-linus

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>

The size of struct btrfs_ioctl_fs_info_args is as big as 1KB, so
don't declare the variable on stack.
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>

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>

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>