Commit Graph

255107 Commits

Author SHA1 Message Date
Liu Bo
65450aa645 Btrfs: reset to appropriate block rsv after orphan operations
While truncating free space cache, we forget to change trans->block_rsv
back to the original one, but leave it with the orphan_block_rsv, and
then with option inode_cache enable, it leads to countless warnings of
btrfs_alloc_free_block and btrfs_orphan_commit_root:

WARNING: at fs/btrfs/extent-tree.c:5711 btrfs_alloc_free_block+0x180/0x350 [btrfs]()
...
WARNING: at fs/btrfs/inode.c:2193 btrfs_orphan_commit_root+0xb0/0xc0 [btrfs]()

Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-09-11 10:52:24 -04:00
Josef Bacik
ddf23b3fc6 Btrfs: skip locking if searching the commit root in csum lookup
It's not enough to just search the commit root, since we could be cow'ing the
very block we need to search through, which would mean that its locked and we'll
still deadlock.  So use path->skip_locking as well.  Thanks,

Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-09-11 10:52:24 -04:00
Sergei Trofimovich
e0b6d65be5 btrfs: fix warning in iput for bad-inode
iput() shouldn't be called for inodes in I_NEW state.
We need to mark inode as constructed first.

WARNING: at fs/inode.c:1309 iput+0x20b/0x210()
Call Trace:
 [<ffffffff8103e7ba>] warn_slowpath_common+0x7a/0xb0
 [<ffffffff8103e805>] warn_slowpath_null+0x15/0x20
 [<ffffffff810eaf0b>] iput+0x20b/0x210
 [<ffffffff811b96fb>] btrfs_iget+0x1eb/0x4a0
 [<ffffffff811c3ad6>] btrfs_run_defrag_inodes+0x136/0x210
 [<ffffffff811ad55f>] cleaner_kthread+0x17f/0x1a0
 [<ffffffff81035b7d>] ? sub_preempt_count+0x9d/0xd0
 [<ffffffff811ad3e0>] ? transaction_kthread+0x280/0x280
 [<ffffffff8105af86>] kthread+0x96/0xa0
 [<ffffffff814336d4>] kernel_thread_helper+0x4/0x10
 [<ffffffff8105aef0>] ? kthread_worker_fn+0x190/0x190
 [<ffffffff814336d0>] ? gs_change+0xb/0xb

Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>
CC: Konstantin Khlebnikov <khlebnikov@openvz.org>
Tested-by: David Sterba <dsterba@suse.cz>
CC: Josef Bacik <josef@redhat.com>
CC: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-09-11 10:52:24 -04:00
Liu Bo
14c7cca780 Btrfs: fix an oops when deleting snapshots
We can reproduce this oops via the following steps:

$ mkfs.btrfs /dev/sdb7
$ mount /dev/sdb7 /mnt/btrfs
$ for ((i=0; i<3; i++)); do btrfs sub snap /mnt/btrfs /mnt/btrfs/s_$i; done
$ rm -fr /mnt/btrfs/*
$ rm -fr /mnt/btrfs/*

then we'll get
------------[ cut here ]------------
kernel BUG at fs/btrfs/inode.c:2264!
[...]
Call Trace:
 [<ffffffffa05578c7>] btrfs_rmdir+0xf7/0x1b0 [btrfs]
 [<ffffffff81150b95>] vfs_rmdir+0xa5/0xf0
 [<ffffffff81153cc3>] do_rmdir+0x123/0x140
 [<ffffffff81145ac7>] ? fput+0x197/0x260
 [<ffffffff810aecff>] ? audit_syscall_entry+0x1bf/0x1f0
 [<ffffffff81153d0d>] sys_unlinkat+0x2d/0x40
 [<ffffffff8147896b>] system_call_fastpath+0x16/0x1b
RIP  [<ffffffffa054f7b9>] btrfs_orphan_add+0x179/0x1a0 [btrfs]

When it comes to btrfs_lookup_dentry, we may set a snapshot's inode->i_ino
to BTRFS_EMPTY_SUBVOL_DIR_OBJECTID instead of BTRFS_FIRST_FREE_OBJECTID,
while the snapshot's location.objectid remains unchanged.

However, btrfs_ino() does not take this into account, and returns a wrong ino,
and causes the oops.

Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-09-11 10:52:24 -04:00
Josef Bacik
f1e490a7eb Btrfs: set i_size properly when fallocating and we already
xfstests exposed a problem with preallocate when it fallocates a range that
already has an extent.  We don't set the new i_size properly because we see that
we already have an extent.  This isn't right and we should update i_size if the
space already exists.  With this patch we now pass xfstests 075.  Thanks,

Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-08-18 10:36:39 -04:00
Sage Weil
f81c9cdc56 Btrfs: truncate pages from clone ioctl target range
We need to truncate page cache pages for the clone ioctl target range or
else we'll confuse ourselves to no end.  If the old data was cached, we
used to still see it (until remount).  If the page was partially updated
we used to get a mix of old and new data.

Signed-off-by: Sage Weil <sage@newdream.net>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-08-16 21:09:31 -04:00
Miao Xie
0e58885961 Btrfs: fix uninitialized sync_pending
sync_pending is uninitialized before it be used, fix it.

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-08-16 21:09:31 -04:00
Miao Xie
bb3ac5a4df Btrfs: fix wrong free space information
Btrfs subtracted the size of the allocated space twice when it allocated
the space from the bitmap in the cluster, it broke the free space information
and led to oops finally.

And this patch also fixes the bug that ctl->free_space was subtracted
without lock.

Reported-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-08-16 21:09:31 -04:00
Dan Carpenter
f4ac904c41 btrfs: memory leak in btrfs_add_inode_defrag()
We don't use the defrag struct on this path.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-08-16 21:09:15 -04:00
Li Zefan
c97c2916e2 Btrfs: use plain page_address() in header fields setget functions
We've stopped using highmem for extent buffers.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-08-16 21:09:15 -04:00
Tsutomu Itoh
cb1b69f450 Btrfs: forced readonly when btrfs_drop_snapshot() fails
The filesystem turns readonly instead of returning the error to the
caller when detected error in btrfs_drop_snapshot().
and, because the caller doesn't check the error, the function type is
changed to 'void'.

Signed-off-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-08-16 21:09:15 -04:00
liubo
cdcb725c05 Btrfs: check if there is enough space for balancing smarter
When checking if there is enough space for balancing a block group,
since we do not take raid types into consideration, we do not account
corrent amounts of space that we needed.  This makes us do some extra
work before we get ENOSPC.

Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-08-16 21:09:15 -04:00
liubo
38c01b9605 Btrfs: fix a bug of balance on full multi-disk partitions
When balancing, we'll first try to shrink devices for some space,
but if it is working on a full multi-disk partition with raid protection,
we may encounter a bug, that is, while shrinking, total_bytes may be less
than bytes_used, and btrfs may allocate a dev extent that accesses out of
device's bounds.

Then we will not be able to write or read the data which stores at the end
of the device, and get the followings:

device fsid 0939f071-7ea3-46c8-95df-f176d773bfb6 devid 1 transid 10 /dev/sdb5
Btrfs detected SSD devices, enabling SSD mode
btrfs: relocating block group 476315648 flags 9
btrfs: found 4 extents
attempt to access beyond end of device
sdb5: rw=145, want=546176, limit=546147
attempt to access beyond end of device
sdb5: rw=145, want=546304, limit=546147
attempt to access beyond end of device
sdb5: rw=145, want=546432, limit=546147
attempt to access beyond end of device
sdb5: rw=145, want=546560, limit=546147
attempt to access beyond end of device

Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-08-16 21:09:15 -04:00
liubo
34f3e4f23c Btrfs: fix an oops of log replay
When btrfs recovers from a crash, it may hit the oops below:

------------[ cut here ]------------
kernel BUG at fs/btrfs/inode.c:4580!
[...]
RIP: 0010:[<ffffffffa03df251>]  [<ffffffffa03df251>] btrfs_add_link+0x161/0x1c0 [btrfs]
[...]
Call Trace:
 [<ffffffffa03e7b31>] ? btrfs_inode_ref_index+0x31/0x80 [btrfs]
 [<ffffffffa04054e9>] add_inode_ref+0x319/0x3f0 [btrfs]
 [<ffffffffa0407087>] replay_one_buffer+0x2c7/0x390 [btrfs]
 [<ffffffffa040444a>] walk_down_log_tree+0x32a/0x480 [btrfs]
 [<ffffffffa0404695>] walk_log_tree+0xf5/0x240 [btrfs]
 [<ffffffffa0406cc0>] btrfs_recover_log_trees+0x250/0x350 [btrfs]
 [<ffffffffa0406dc0>] ? btrfs_recover_log_trees+0x350/0x350 [btrfs]
 [<ffffffffa03d18b2>] open_ctree+0x1442/0x17d0 [btrfs]
[...]

This comes from that while replaying an inode ref item, we forget to
check those old conflicting DIR_ITEM and DIR_INDEX items in fs/file tree,
then we will come to conflict corners which lead to BUG_ON().

Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Tested-by: Andy Lutomirski <luto@mit.edu>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-08-16 21:09:15 -04:00
Josef Bacik
d5e2003c2b Btrfs: detect wether a device supports discard
We have a problem where if a user specifies discard but doesn't actually support
it we will return EOPNOTSUPP from btrfs_discard_extent.  This is a problem
because this gets called (in a fashion) from the tree log recovery code, which
has a nice little BUG_ON(ret) after it, which causes us to fail the tree log
replay.  So instead detect wether our devices support discard when we're adding
them and then don't issue discards if we know that the device doesn't support
it.  And just for good measure set ret = 0 in btrfs_issue_discard just in case
we still get EOPNOTSUPP so we don't screw anybody up like this again.  Thanks,

Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-08-16 21:09:15 -04:00
Chris Mason
2ab1ba68ae Btrfs: force unplugs when switching from high to regular priority bios
Btrfs does bio submissions from a worker thread, and each device
has a list of high priority bios and regular priority bios.

Synchronous writes go to the high priority thread while async writes
go to regular list.  This commit brings back an explicit unplug
any time we switch from high to regular priority, which makes it
easier for the block layer to give us low latencies.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-08-05 13:48:18 -04:00
Josef Bacik
0d10ee2e6d Btrfs: don't call writepages from within write_full_page
When doing a writepage we call writepages to try and write out any other dirty
pages in the area.  This could cause problems where we commit a transaction and
then have somebody else dirtying metadata in the area as we could end up writing
out a lot more than we care about, which could cause latency on anybody who is
waiting for the transaction to completely finish committing.  Thanks,

Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-08-01 14:37:36 -04:00
Mitch Harder
341d14f161 Btrfs: Remove unused variable 'last_index' in file.c
The variable 'last_index' is calculated in the __btrfs_buffered_write
function and passed as a parameter to the prepare_pages function,
but is not used anywhere in the prepare_pages function.

Remove instances of 'last_index' in these functions.

Signed-off-by: Mitch Harder <mitch.harder@sabayonlinux.org>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-08-01 14:32:39 -04:00
Xiao Guangrong
69261c4b6a Btrfs: clean up for find_first_extent_bit()
find_first_extent_bit() and find_first_extent_bit_state() share
most of the code, and we can just make the former call the latter.

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-08-01 14:32:39 -04:00
Xiao Guangrong
ded91f0814 Btrfs: clean up for wait_extent_bit()
We can just use cond_resched_lock().

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-08-01 14:32:38 -04:00
Xiao Guangrong
3150b69969 Btrfs: clean up for insert_state()
Don't duplicate set_state_bits().

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-08-01 14:32:30 -04:00
Xiao Guangrong
3a6d457ec7 Btrfs: remove unused members from struct extent_state
These members are not used at all.

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-08-01 14:30:50 -04:00
Li Zefan
4d2c8f62f1 Btrfs: clean up code for merging extent maps
unpin_extent_cache() and add_extent_mapping() shares the same code
that merges extent maps.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-08-01 14:30:50 -04:00
Li Zefan
ed64f06652 Btrfs: clean up code for extent_map lookup
lookup_extent_map() and search_extent_map() can share most of code.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-08-01 14:30:49 -04:00
Li Zefan
7e016a038e Btrfs: clean up search_extent_mapping()
rb_node returned by __tree_search() can be a valid pointer or NULL,
but won't be some errno.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-08-01 14:30:49 -04:00
Li Zefan
85d85a743d Btrfs: remove redundant code for dir item lookup
When we search a dir item with a specific hash code, we can
just return NULL without further checking if btrfs_search_slot()
returns 1.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-08-01 14:30:48 -04:00
Li Zefan
9b89d95a14 Btrfs: make acl functions really no-op if acl is not enabled
So there's no overhead for something we don't use.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-08-01 14:30:48 -04:00
Li Zefan
15de900d08 Btrfs: remove remaining ref-cache code
Since commit f2a97a9dbd
("btrfs: remove all unused functions"), there's no extern functions
at all in ref-cache.c, so just remove the remaining dead code.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-08-01 14:30:47 -04:00
Li Zefan
b9c8300c2a Btrfs: remove a BUG_ON() in btrfs_commit_transaction()
wait_for_commit() always returns 0.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-08-01 14:30:47 -04:00
Li Zefan
72d63ed642 Btrfs: use wait_event()
Use wait_event() when possible to avoid code duplication.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-08-01 14:30:46 -04:00
Li Zefan
e55179b3d7 Btrfs: check the nodatasum flag when writing compressed files
If mounting with nodatasum option, we won't csum file data for
general write or direct-io write, and this rule should also be
applied when writing compressed files.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-08-01 14:30:46 -04:00
Li Zefan
77906a5075 Btrfs: copy string correctly in INO_LOOKUP ioctl
Memory areas [ptr, ptr+total_len] and [name, name+total_len]
may overlap, so it's wrong to use memcpy().

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-08-01 14:30:45 -04:00
Josef Bacik
b783e62d96 Btrfs: don't print the leaf if we had an error
In __btrfs_free_extent we will print the leaf if we fail to find the extent we
wanted, but the problem is if we get an error we won't have a leaf so often this
leads to a NULL pointer dereference and we lose the error that actually
occurred.  So only print the leaf if ret > 0, which means we didn't find the
item we were looking for but we didn't error either.  This way the error is
preserved.

Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-08-01 14:30:45 -04:00
Mark Fasheh
bf5f32ecb6 btrfs: make btrfs_set_root_node void
This is fairly trivial - btrfs_set_root_node() - always returns zero so we
can just make it void.  All callers ignore the return code now anyway.  I
also made sure to check that none of the functions that
btrfs_set_root_node() calls returns an error that we might have needed to
catch and pass back.

Signed-off-by: Mark Fasheh <mfasheh@suse.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-08-01 14:30:44 -04:00
liubo
ff1f2b4407 Btrfs: fix oops while writing data to SSD partitions
Here I have a two SSD-partitions btrfs, and they are defaultly set to
"data=raid0, metadata=raid1", then I try to fill my btrfs partition
till "No space left on device", via "dd if=/dev/zero of=/mnt/btrfs/tmp".

I get an oops panic from kernel BUG at fs/btrfs/extent-tree.c:5199!, which
refers to find_free_extent's
BUG_ON(index != get_block_group_index(block_group));

In SSD mode, in order to find enough space to alloc, we may check the
block_group cache which has been checked sometime before, but the index is not
updated, where it hits the BUG_ON.

Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Acked-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-08-01 14:30:44 -04:00
WuBo
61cfea9bb8 Btrfs: Protect the readonly flag of block group
The access for ro in btrfs_block_group_cache should be protected
because of the racy lock in relocation.

Signed-off-by: Wu Bo <wu.bo@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-08-01 14:30:43 -04:00
Jeff Mahoney
1bf85046e4 btrfs: Make extent-io callbacks that never fail return void
The set/clear bit and the extent split/merge hooks only ever return 0.

 Changing them to return void simplifies the error handling cases later.

 This patch changes the hook prototypes, the single implementation of each,
 and the functions that call them to return void instead.

 Since all four of these hooks execute under a spinlock, they're necessarily
 simple.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-08-01 14:30:43 -04:00
Li Zefan
b6973aa622 Btrfs: fix readahead in file defrag
We passed the wrong value to btrfs_force_ra(). Fix this by changing
the argument of btrfs_force_ra() from last_index to nr_page.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-08-01 14:30:42 -04:00
Tsutomu Itoh
b532402e4d Btrfs: return error to caller when btrfs_unlink() failes
When btrfs_unlink_inode() and btrfs_orphan_add() in btrfs_unlink()
are error, the error code is returned to the caller instead of
BUG_ON().

Signed-off-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-08-01 14:30:42 -04:00
Wanlong Gao
a0f98dde11 Btrfs:don't check the return value of __btrfs_add_inode_defrag
Don't need to check the return value of __btrfs_add_inode_defrag(),
since it will always return 0.

Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-08-01 14:30:41 -04:00
Chris Mason
b43b31bdf2 Merge branch 'alloc_path' of git://git.kernel.org/pub/scm/linux/kernel/git/mfasheh/btrfs-error-handling into for-linus 2011-08-01 14:27:34 -04:00
Chris Mason
ff95acb673 Merge branch 'integration' into for-linus 2011-07-27 16:18:13 -04:00
Chris Mason
75c195a2ca Btrfs: make sure reserve_metadata_bytes doesn't leak out strange errors
The btrfs transaction code will return any errors that come from
reserve_metadata_bytes.  We need to make sure we don't return funny
things like 1 or EAGAIN.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-07-27 16:11:41 -04:00
Chris Mason
2cf8572dac Btrfs: use the commit_root for reading free_space_inode crcs
Now that we are using regular file crcs for the free space cache,
we can deadlock if we try to read the free_space_inode while we are
updating the crc tree.

This commit fixes things by using the commit_root to read the crcs.  This is
safe because we the free space cache file would already be loaded if
that block group had been changed in the current transaction.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-07-27 12:46:48 -04:00
Chris Mason
19b6caf4ac Btrfs: reduce extent_state lock contention for metadata
For metadata buffers that don't straddle pages (all of them), btrfs
can safely use the page uptodate bits and extent_buffer uptodate bit
instead of needing to use the extent_state tree.

This greatly reduces contention on the state tree lock.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-07-27 12:46:47 -04:00
Chris Mason
31533fb263 Btrfs: remove lockdep magic from btrfs_next_leaf
Before the reader/writer locks, btrfs_next_leaf needed to keep
the path blocking to avoid making lockdep upset.

Now that btrfs_next_leaf only takes read locks, this isn't required.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-07-27 12:46:47 -04:00
Chris Mason
85d4e46111 Btrfs: make a lockdep class for each root
This patch was originally from Tejun Heo.  lockdep complains about the btrfs
locking because we sometimes take btree locks from two different trees at the
same time.  The current classes are based only on level in the btree, which
isn't enough information for lockdep to figure out if the lock is safe.

This patch makes a class for each type of tree, and lumps all the FS trees that
actually have files and directories into the same class.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-07-27 12:46:46 -04:00
Chris Mason
bd681513fa Btrfs: switch the btrfs tree locks to reader/writer
The btrfs metadata btree is the source of significant
lock contention, especially in the root node.   This
commit changes our locking to use a reader/writer
lock.

The lock is built on top of rw spinlocks, and it
extends the lock tracking to remember if we have a
read lock or a write lock when we go to blocking.  Atomics
count the number of blocking readers or writers at any
given time.

It removes all of the adaptive spinning from the old code
and uses only the spinning/blocking hints inside of btrfs
to decide when it should continue spinning.

In read heavy workloads this is dramatically faster.  In write
heavy workloads we're still faster because of less contention
on the root node lock.

We suffer slightly in dbench because we schedule more often
during write locks, but all other benchmarks so far are improved.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-07-27 12:46:46 -04:00
Josef Bacik
81317fdedd Btrfs: fix deadlock when throttling transactions
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>
2011-07-27 12:46:46 -04:00
Chris Mason
a65917156e Btrfs: stop using highmem for extent_buffers
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>
2011-07-27 12:46:45 -04:00