Commit Graph

312211 Commits

Author SHA1 Message Date
Josef Bacik
66657b318e Btrfs: barrier before waitqueue_active
We need a barrir before calling waitqueue_active otherwise we will miss
wakeups.  So in places that do atomic_dec(); then atomic_read() use
atomic_dec_return() which imply a memory barrier (see memory-barriers.txt)
and then add an explicit memory barrier everywhere else that need them.
Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2012-08-28 16:53:33 -04:00
Arne Jansen
1fa11e265f Btrfs: fix deadlock in wait_for_more_refs
Commit a168650c introduced a waiting mechanism to prevent busy waiting in
btrfs_run_delayed_refs. This can deadlock with btrfs_run_ordered_operations,
where a tree_mod_seq is held while waiting for the io to complete, while
the end_io calls btrfs_run_delayed_refs.
This whole mechanism is unnecessary. If not enough runnable refs are
available to satisfy count, just return as count is more like a guideline
than a strict requirement.
In case we have to run all refs, commit transaction makes sure that no
other threads are working in the transaction anymore, so we just assert
here that no refs are blocked.

Signed-off-by: Arne Jansen <sensille@gmx.net>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-08-28 16:53:32 -04:00
Fengguang Wu
6209526531 btrfs: fix second lock in btrfs_delete_delayed_items()
Fix a real bug caught by coccinelle.

fs/btrfs/delayed-inode.c:1013:1-11: second lock on line 1013

Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
2012-08-28 16:53:31 -04:00
Josef Bacik
c329861da4 Btrfs: don't allocate a seperate csums array for direct reads
We've been allocating a big array for csums instead of storing them in the
io_tree like we do for buffered reads because previously we were locking the
entire range, so we didn't have an extent state for each sector of the
range.  But now that we do the range locking as we map the buffers we can
limit the mapping lenght to sectorsize and use the private part of the
io_tree for our csums.  This allows us to avoid an extra memory allocation
for direct reads which could incur latency.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2012-08-28 16:53:30 -04:00
Josef Bacik
99f5944b84 Btrfs: do not strdup non existent strings
When we close devices we add back empty devices for some reason that escapes
me.  In the case of a missing dev we don't allocate an rcu_string for it's
name, so check to see if the device has a name and if it doesn't don't
bother strdup()'ing it.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2012-08-28 16:53:29 -04:00
Josef Bacik
aa9ddcd4b5 Btrfs: do not use missing devices when showing devname
If you do the following

mkfs.btrfs /dev/sdb /dev/sdc
rmmod btrfs
dd if=/dev/zero of=/dev/sdb bs=1M count=1
mount -o degraded /dev/sdc /mnt/btrfs-test

the box will panic trying to deref the name for the missing dev since it is
the lower numbered devid.  So fix show_devname to not use missing devices.
Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2012-08-28 16:53:29 -04:00
Stefan Behrens
3627bf4503 Btrfs: fix that error value is changed by mistake
In iterate_inodes_from_logical() the error result from
extent_from_logical() is patched by mistake. Typically ENOENT is
patched to EINVAL because (-ENOENT & BTRFS_EXTENT_FLAG_TREE_BLOCK)
evaluates to true.

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
2012-08-28 16:53:28 -04:00
Josef Bacik
eb838e73dc Btrfs: lock extents as we map them in DIO
A deadlock in xfstests 113 was uncovered by commit

d187663ef2

This is because we would not return EIOCBQUEUED for short AIO reads, instead
we'd wait for the DIO to complete and then return the amount of data we
transferred, which would allow our stuff to unlock the remaning amount.  But
with this change this no longer happens, so if we have a short AIO read (for
example if we try to read past EOF), we could leave the section from EOF to
the end of where we tried to read locked.  Fixing this is tricky since there
is no clear way to know exactly how much data DIO truly submitted for IO, so
to make this less hard on ourselves and less combersome we need to lock the
extents as we try to map them, and then we unlock any areas we didn't
actually map.  This makes us completely safe from deadlocks and reliance on
a particular behavior of the DIO code.  This also lays the groundwork for
allowing us to use the normal csum storage method for reads which means we
can remove an allocation.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2012-08-28 16:53:27 -04:00
Dan Carpenter
dadd1105ca Btrfs: fix some endian bugs handling the root times
"trans->transid" is cpu endian but we want to store the data as little
endian.  "item->ctime.nsec" is only 32 bits, not 64.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
2012-08-28 16:53:26 -04:00
Dan Carpenter
55e591ffde Btrfs: unlock on error in btrfs_delalloc_reserve_metadata()
We should release this mutex before returning the error code.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
2012-08-28 16:53:25 -04:00
Dan Carpenter
57a5a88203 Btrfs: checking for NULL instead of IS_ERR
add_qgroup_rb() never returns NULL, only error pointers.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
2012-08-28 16:53:25 -04:00
Dan Carpenter
5986802c2f Btrfs: fix some error codes in btrfs_qgroup_inherit()
These are returning zero when it should be returning a negative error
code.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
2012-08-28 16:53:24 -04:00
Stefan Behrens
aa2ffd0616 Btrfs: fix a misplaced address operator in a condition
This should obviously not be "if (&flag)" but "if (flag)".

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
2012-08-28 16:53:23 -04:00
Chris Mason
b24baf6917 Btrfs: uninit variable fixes in send/receive
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-07-25 19:21:10 -04:00
Chris Mason
113c1cb530 Merge branch 'send-v2' of git://github.com/ablock84/linux-btrfs into for-linus
This is the kernel portion of btrfs send/receive

Conflicts:
	fs/btrfs/Makefile
	fs/btrfs/backref.h
	fs/btrfs/ctree.c
	fs/btrfs/ioctl.c
	fs/btrfs/ioctl.h

Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-07-25 19:19:10 -04:00
Alexander Block
31db9f7c23 Btrfs: introduce BTRFS_IOC_SEND for btrfs send/receive
This patch introduces the BTRFS_IOC_SEND ioctl that is
required for send. It allows btrfs-progs to implement
full and incremental sends. Patches for btrfs-progs will
follow.

Signed-off-by: Alexander Block <ablock84@googlemail.com>
Reviewed-by: David Sterba <dave@jikos.cz>
Reviewed-by: Arne Jansen <sensille@gmx.net>
Reviewed-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
Reviewed-by: Alex Lyakas <alex.bolshoy.btrfs@gmail.com>
2012-07-25 23:30:19 +02:00
Alexander Block
7069830a9e Btrfs: add btrfs_compare_trees function
This function is used to find the differences between
two trees. The tree compare skips whole subtrees if it
detects shared tree blocks and thus is pretty fast.

Signed-off-by: Alexander Block <ablock84@googlemail.com>
Reviewed-by: David Sterba <dave@jikos.cz>
Reviewed-by: Arne Jansen <sensille@gmx.net>
Reviewed-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
Reviewed-by: Alex Lyakas <alex.bolshoy.btrfs@gmail.com>
2012-07-25 23:30:14 +02:00
Alexander Block
8ea05e3a42 Btrfs: introduce subvol uuids and times
This patch introduces uuids for subvolumes. Each
subvolume has it's own uuid. In case it was snapshotted,
it also contains parent_uuid. In case it was received,
it also contains received_uuid.

It also introduces subvolume ctime/otime/stime/rtime. The
first two are comparable to the times found in inodes. otime
is the origin/creation time and ctime is the change time.
stime/rtime are only valid on received subvolumes.
stime is the time of the subvolume when it was
sent. rtime is the time of the subvolume when it was
received.

Additionally to the times, we have a transid for each
time. They are updated at the same place as the times.

btrfs receive uses stransid and rtransid to find out
if a received subvolume changed in the meantime.

If an older kernel mounts a filesystem with the
extented fields, all fields become invalid. The next
mount with a new kernel will detect this and reset the
fields.

Signed-off-by: Alexander Block <ablock84@googlemail.com>
Reviewed-by: David Sterba <dave@jikos.cz>
Reviewed-by: Arne Jansen <sensille@gmx.net>
Reviewed-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
Reviewed-by: Alex Lyakas <alex.bolshoy.btrfs@gmail.com>
2012-07-25 23:28:38 +02:00
Alexander Block
91cb916ca2 Btrfs: make iref_to_path non static
Make iref_to_path non static (needed in send) and rename
it to btrfs_iref_to_path

Signed-off-by: Alexander Block <ablock84@googlemail.com>
2012-07-25 23:25:06 +02:00
Chris Mason
cd1cfc4915 Btrfs: add a barrier before a waitqueue_active check
We were missing wakeups on the delayed ref waitqueue due
to races on waitqueue_active.

Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-07-25 16:15:08 -04:00
Chris Mason
e9fbcb4220 Btrfs: call the ordered free operation without any locks held
Each ordered operation has a free callback, and this was called with the
worker spinlock held.  Josef made the free callback also call iput,
which we can't do with the spinlock.

This drops the spinlock for the free operation and grabs it again before
moving through the rest of the list.  We'll circle back around to this
and find a cleaner way that doesn't bounce the lock around so much.

Signed-off-by: Chris Mason <chris.mason@fusionio.com>
cc: stable@kernel.org
2012-07-25 16:15:07 -04:00
Mitch Harder
2b0ce2c290 Btrfs: Check INCOMPAT flags on remount and add helper function
In support of the recently added capability to remount with lzo
compression, provide a helper function to check the compression
INCOMPAT flags when remounting with lzo compression, and set
the flags if necessary.

Also, implement the new helper function when defragmenting with
explicit lzo compression and when setting the default subvolume.

Signed-off-by: Mitch Harder <mitch.harder@sabayonlinux.org>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-07-25 16:14:31 -04:00
Chris Mason
b478b2baa3 Merge branch 'qgroup' of git://git.jan-o-sch.net/btrfs-unstable into for-linus
Conflicts:
	fs/btrfs/ioctl.c
	fs/btrfs/ioctl.h
	fs/btrfs/transaction.c
	fs/btrfs/transaction.h

Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-07-25 16:11:38 -04:00
Arne Jansen
e679376911 Btrfs: add helper for tree enumeration
Often no exact match is wanted but just the next lower or
higher item. There's a lot of duplicated code throughout
btrfs to deal with the corner cases. This patch adds a
helper function that can facilitate searching.

Signed-off-by: Arne Jansen <sensille@gmx.net>
2012-07-25 17:33:18 +02:00
David Sterba
362a20c5e2 btrfs: allow cross-subvolume file clone
Lift the EXDEV condition and allow different root trees for files being
cloned, then pass source inode's root when searching for extents.
Cloning is not allowed to cross vfsmounts, ie. when two subvolumes from
one filesystem are mounted separately.

Signed-off-by: David Sterba <dsterba@suse.cz>
2012-07-25 17:33:09 +02:00
Liu Bo
67c9684f48 Btrfs: improve multi-thread buffer read
While testing with my buffer read fio jobs[1], I find that btrfs does not
perform well enough.

Here is a scenario in fio jobs:

We have 4 threads, "t1 t2 t3 t4", starting to buffer read a same file,
and all of them will race on add_to_page_cache_lru(), and if one thread
successfully puts its page into the page cache, it takes the responsibility
to read the page's data.

And what's more, reading a page needs a period of time to finish, in which
other threads can slide in and process rest pages:

     t1          t2          t3          t4
   add Page1
   read Page1  add Page2
     |         read Page2  add Page3
     |            |        read Page3  add Page4
     |            |           |        read Page4
-----|------------|-----------|-----------|--------
     v            v           v           v
    bio          bio         bio         bio

Now we have four bios, each of which holds only one page since we need to
maintain consecutive pages in bio.  Thus, we can end up with far more bios
than we need.

Here we're going to
a) delay the real read-page section and
b) try to put more pages into page cache.

With that said, we can make each bio hold more pages and reduce the number
of bios we need.

Here is some numbers taken from fio results:
         w/o patch                 w patch
       -------------  --------  ---------------
READ:    745MB/s        +25%       934MB/s

[1]:
[global]
group_reporting
thread
numjobs=4
bs=32k
rw=read
ioengine=sync
directory=/mnt/btrfs/

[READ]
filename=foobar
size=2000M
invalidate=1

Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2012-07-23 16:28:10 -04:00
Liu Bo
df57dbe6bf Btrfs: make btrfs's allocation smoothly with preallocation
For backref walking, we've introduce delayed ref's sequence.  However,
it changes our preallocation behavior.

The story is that when we preallocate an extent and then mark it written
piece by piece, the ideal case should be that we don't need to COW the
extent, which is why we use 'preallocate'.

But we may not make use of preallocation, since when we check for cross refs on
the extent, we may have two ref entries which have the same content except
the sequence value, and we recognize them as cross refs and do COW to allocate
another extent.

So we end up with several pieces of space instead of an whole extent.

Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2012-07-23 16:28:10 -04:00
Josef Bacik
51561ffec9 Btrfs: lock the transition from dirty to writeback for an eb
There is a small window where an eb can have no IO bits set on it, which
could potentially result in extent_buffer_under_io() returning false when we
want it to return true, which could result in not fun things happening.  So
in order to protect this case we need to hold the refs_lock when we make
this transition to make sure we get reliable results out of
extent_buffer_udner_io().  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2012-07-23 16:28:09 -04:00
Josef Bacik
594831c4b2 Btrfs: fix potential race in extent buffer freeing
This sounds sort of impossible but it is the only thing I can think of and
at the very least it is theoretically possible so here it goes.

If we are in try_release_extent_buffer we will check that the ref count on
the extent buffer is 1 and not under IO, and then go down and clear the tree
ref.  If between this check and clearing the tree ref somebody else comes in
and grabs a ref on the eb and the marks it dirty before
try_release_extent_buffer() does it's tree ref clear we can end up with a
dirty eb that will be freed while it is still dirty which will result in a
panic.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2012-07-23 16:28:09 -04:00
Josef Bacik
e64860aa05 Btrfs: don't return true in releasepage unless we actually freed the eb
I noticed while looking at an extent_buffer race that we will
unconditionally return 1 if we get down to release_extent_buffer after
clearing the tree ref.  However we can easily race in here and get a ref on
the eb and not actually free the eb.  So make release_extent_buffer return 1
if it free'd the eb and 0 if not so we can be a little kinder to the vm.
Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2012-07-23 16:28:08 -04:00
Stefan Behrens
a98cdb85b9 Btrfs: suppress printk() if all device I/O stats are zero
Code is added to suppress the I/O stats printing at mount time if all
statistic values are zero.

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
2012-07-23 16:28:07 -04:00
Stefan Behrens
5021976d8d Btrfs: remove unwanted printk() for btrfs device I/O stats
People complained about the annoying kernel log message
"btrfs: no dev_stats entry found ... (OK on first mount after mkfs)"
everytime a filesystem is mounted for the first time after running
mkfs. Since the distribution of the btrfs-progs is not synchronized
to the kernel version, mkfs like it is now will be used also in the
future. Then this message is not useful to find errors, it is just
annoying. This commit removes the printk().

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
2012-07-23 16:28:07 -04:00
Li Zefan
18077bb413 Btrfs: rewrite BTRFS_SETGET_FUNCS
BTRFS_SETGET_FUNCS macro is used to generate btrfs_set_foo() and
btrfs_foo() functions, which read and write specific fields in the
extent buffer.

The total number of set/get functions is ~200, but in fact we only
need 8 functions: 2 for u8 field, 2 for u16, 2 for u32 and 2 for u64.

It results in redunction of ~37K bytes.

   text    data     bss     dec     hex filename
 629661   12489     216  642366   9cd3e fs/btrfs/btrfs.o.orig
 592637   12489     216  605342   93c9e fs/btrfs/btrfs.o

Signed-off-by: Li Zefan <lizefan@huawei.com>
2012-07-23 16:28:06 -04:00
Li Zefan
293f7e0740 Btrfs: zero unused bytes in inode item
The otime field is not zeroed, so users will see random otime in an old
filesystem with a new kernel which has otime support in the future.

The reserved bytes are also not zeroed, and we'll have compatibility
issue if we make use of those bytes.

Signed-off-by: Li Zefan <lizefan@huawei.com>
2012-07-23 16:28:05 -04:00
Li Zefan
b4d7c3c945 Btrfs: kill free_space pointer from inode structure
Inodes always allocate free space with BTRFS_BLOCK_GROUP_DATA type,
which means every inode has the same BTRFS_I(inode)->free_space pointer.

This shrinks struct btrfs_inode by 4 bytes (or 8 bytes on 64 bits).

Signed-off-by: Li Zefan <lizefan@huawei.com>
2012-07-23 16:28:05 -04:00
Anand Jain
d5b025d510 btrfs read error corrected message floods the console during recovery
Changing printk_in_rcu to printk_ratelimited_in_rcu will suffice

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2012-07-23 16:28:04 -04:00
Jan Schmidt
e6466e354a Btrfs: fix buffer leak in btrfs_next_old_leaf
When calling btrfs_next_old_leaf, we were leaking an extent buffer in the
rare case of using the deadlock avoidance code needed for the tree mod log.

Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2012-07-23 16:28:03 -04:00
Liu Bo
f6175efab1 Btrfs: do not count in readonly bytes
If a block group is ro, do not count its entries in when we dump space info.

Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2012-07-23 16:28:03 -04:00
Liu Bo
799ffc3c31 Btrfs: add ro notification to dump_space_info
Block group has ro attributes, make dump_space_info show it.

Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2012-07-23 16:28:02 -04:00
Liu Bo
cf7c1ef6e1 Btrfs: fix a bug of writting free space cache during balance
Here is the whole story:
1)
A free space cache consists of two parts:
o  free space cache inode, which is special becase it's stored in root tree.
o  free space info, which is stored as the above inode's file data.

But we only build up another new inode and does not flush its free space info
onto disk when we _clear and setup_ free space cache, and this ends up with
that the block group cache's cache_state remains DC_SETUP instead of DC_WRITTEN.

And holding DC_SETUP means that we will not truncate this free space cache inode,
which means the disk offset of its file extent will remain _unchanged_ at least
until next transaction finishes committing itself.

2)
We can set a block group readonly when we relocate the block group.

However,
if the readonly block group covers the disk offset where our free space cache
inode is going to write, it will force the free space cache inode into
cow_file_range() and it'll end up hitting a BUG_ON.

3)
Due to the above analysis, we fix this bug by adding the missing dirty flag.

4)
However, it's not over, there is still another case, nospace_cache.

With nospace_cache, we do not want to set dirty flag, instead we just truncate
free space cache inode and bail out with setting cache state DC_WRITTEN.

We can benifit from it since it saves us another 'pre-allocation' part which
usually costs a lot.

Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2012-07-23 16:28:02 -04:00
Liu Bo
0678938423 Btrfs: do not abort transaction in prealloc case
During disk balance, we prealloc new file extent for file data relocation,
but we may fail in 'no available space' case, and it leads to flipping btrfs
into readonly.

It is not necessary to bail out and abort transaction since we do have several
ways to rescue ourselves from ENOSPC case.

Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2012-07-23 16:28:01 -04:00
Liu Bo
83eea1f1ba Btrfs: kill root from btrfs_is_free_space_inode
Since root can be fetched via BTRFS_I macro directly, we can save an args
for btrfs_is_free_space_inode().

Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2012-07-23 16:28:00 -04:00
Liu Bo
51a8cf9d2d Btrfs: fix btrfs_is_free_space_inode to recognize btree inode
For btree inode, its root is also 'tree root', so btree inode can be
misunderstood as a free space inode.

We should add one more check for btree inode.

Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2012-07-23 16:28:00 -04:00
Stefan Behrens
c0901581ad Btrfs: avoid I/O repair BUG() from btree_read_extent_buffer_pages()
From btree_read_extent_buffer_pages(), currently repair_io_failure()
can be called with mirror_num being zero when submit_one_bio() returned
an error before. This used to cause a BUG_ON(!mirror_num) in
repair_io_failure() and indeed this is not a case that needs the I/O
repair code to rewrite disk blocks.
This commit prevents calling repair_io_failure() in this case and thus
avoids the BUG_ON() and malfunction.

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2012-07-23 16:27:59 -04:00
Josef Bacik
f4c738c2e7 Btrfs: rework shrink_delalloc
So shrink_delalloc has grown all sorts of cruft over the years thanks to
many reworkings of how we track enospc.  What happens now as we fill up the
disk is we will loop for freaking ever hoping to reclaim a arbitrary amount
of space of metadata, this was from when everybody flushed at the same time.
Now we only have people flushing one at a time.  So instead of trying to
reclaim a huge amount of space, just try to flush a decent chunk of space,
and stop looping as soon as we have enough free space to satisfy our
reservation.  This makes xfstests 224 go much faster.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2012-07-23 16:27:58 -04:00
Liu Bo
b9ca0664dc Btrfs: do not set subvolume flags in readonly mode
$ mkfs.btrfs /dev/sdb7
$ btrfstune -S1 /dev/sdb7
$ mount /dev/sdb7 /mnt/btrfs
mount: block device /dev/sdb7 is write-protected, mounting read-only
$ btrfs dev add /dev/sdb8 /mnt/btrfs/

Now we get a btrfs in which mnt flags has readonly but sb flags does
not.  So for those ioctls that only check sb flags with MS_RDONLY, it
is going to be a problem.
Setting subvolume flags is such an ioctl, we should use mnt_want_write_file()
to check RO flags.

Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
2012-07-23 16:27:58 -04:00
Liu Bo
e54bfa3104 Btrfs: use mnt_want_write_file instead of mnt_want_write
mnt_want_write_file is faster when file has been opened for write.

Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
2012-07-23 16:27:57 -04:00
Liu Bo
768e9dfe82 Btrfs: remove redundant r/o check for superblock
mnt_want_write() and mnt_want_write_file() will check sb->s_flags with
MS_RDONLY, and we don't need to do it ourselves.

Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
2012-07-23 16:27:56 -04:00
Liu Bo
a874a63e13 Btrfs: check write access to mount earlier while creating snapshots
Move check of write access to mount into upper functions so that we can
use mnt_want_write_file instead, which is faster than mnt_want_write.

Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
2012-07-23 16:27:56 -04:00
Liu Bo
287082b0bd Btrfs: fix typo in cow_file_range_async and async_cow_submit
It should be 10 * 1024 * 1024.

Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2012-07-23 16:27:55 -04:00