Commit Graph

129 Commits

Author SHA1 Message Date
Linus Torvalds aa3fc52546 Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable
* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable: (24 commits)
  Btrfs: don't use migrate page without CONFIG_MIGRATION
  Btrfs: deal with DIO bios that span more than one ordered extent
  Btrfs: setup blank root and fs_info for mount time
  Btrfs: fix fiemap
  Btrfs - fix race between btrfs_get_sb() and umount
  Btrfs: update inode ctime when using links
  Btrfs: make sure new inode size is ok in fallocate
  Btrfs: fix typo in fallocate to make it honor actual size
  Btrfs: avoid NULL pointer deref in try_release_extent_buffer
  Btrfs: make btrfs_add_nondir take parent inode as an argument
  Btrfs: hold i_mutex when calling btrfs_log_dentry_safe
  Btrfs: use dget_parent where we can UPDATED
  Btrfs: fix more ESTALE problems with NFS
  Btrfs: handle NFS lookups properly
  btrfs: make 1-bit signed fileds unsigned
  btrfs: Show device attr correctly for symlinks
  btrfs: Set file size correctly in file clone
  btrfs: Check if dest_offset is block-size aligned before cloning file
  Btrfs: handle the space_cache option properly
  btrfs: Fix early enospc because 'unused' calculated with wrong sign.
  ...
2010-11-29 14:11:08 -08:00
Josef Bacik 975f84fee2 Btrfs: fix fiemap
There are two big problems currently with FIEMAP

1) We return extents for holes.  This isn't supposed to happen, we just don't
return extents for holes and then userspace interprets the lack of an extent as
a hole.

2) We sometimes don't set FIEMAP_EXTENT_LAST properly.  This is because we wait
to see a EXTENT_FLAG_VACANCY flag on the em, but this won't happen if say we ask
fiemap to map up to the last extent in a file, and there is nothing but holes up
to the i_size.  To fix this we need to lookup the last extent in this file and
save the logical offset, so if we happen to try and map that extent we can be
sure to set FIEMAP_EXTENT_LAST.

With this patch we now pass xfstest 225, which we never have before.

Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-11-27 13:37:50 -05:00
Chris Mason 45f49bce99 Btrfs: avoid NULL pointer deref in try_release_extent_buffer
If we fail to find a pointer in the radix tree, don't try
to deref the NULL one we do have.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-11-21 22:27:44 -05:00
Miao Xie 88f794ede7 btrfs: cleanup duplicate bio allocating functions
extent_bio_alloc() and compressed_bio_alloc() are similar, cleanup
similar source code.

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-11-21 22:26:03 -05:00
Linus Torvalds 925d169f5b Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable: (39 commits)
  Btrfs: deal with errors from updating the tree log
  Btrfs: allow subvol deletion by unprivileged user with -o user_subvol_rm_allowed
  Btrfs: make SNAP_DESTROY async
  Btrfs: add SNAP_CREATE_ASYNC ioctl
  Btrfs: add START_SYNC, WAIT_SYNC ioctls
  Btrfs: async transaction commit
  Btrfs: fix deadlock in btrfs_commit_transaction
  Btrfs: fix lockdep warning on clone ioctl
  Btrfs: fix clone ioctl where range is adjacent to extent
  Btrfs: fix delalloc checks in clone ioctl
  Btrfs: drop unused variable in block_alloc_rsv
  Btrfs: cleanup warnings from gcc 4.6 (nonbugs)
  Btrfs: Fix variables set but not read (bugs found by gcc 4.6)
  Btrfs: Use ERR_CAST helpers
  Btrfs: use memdup_user helpers
  Btrfs: fix raid code for removing missing drives
  Btrfs: Switch the extent buffer rbtree into a radix tree
  Btrfs: restructure try_release_extent_buffer()
  Btrfs: use the flusher threads for delalloc throttling
  Btrfs: tune the chunk allocation to 5% of the FS as metadata
  ...

Fix up trivial conflicts in fs/btrfs/super.c and fs/fs-writeback.c, and
remove use of INIT_RCU_HEAD in fs/btrfs/extent_io.c (that init macro was
useless and removed in commit 5e8067adfdba: "rcu head remove init")
2010-10-30 09:05:48 -07:00
Andi Kleen 559af82114 Btrfs: cleanup warnings from gcc 4.6 (nonbugs)
These are all the cases where a variable is set, but not read which are
not bugs as far as I can see, but simply leftovers.

Still needs more review.

Found by gcc 4.6's new warnings

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-10-29 15:14:37 -04:00
Andi Kleen 411fc6bcef Btrfs: Fix variables set but not read (bugs found by gcc 4.6)
These are all the cases where a variable is set, but not
read which are really bugs.

- Couple of incorrect error handling fixed.
- One incorrect use of a allocation policy
- Some other things

Still needs more review.

Found by gcc 4.6's new warnings.

[akpm@linux-foundation.org: fix build.  Might have been bitrot]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-10-29 15:14:31 -04:00
Miao Xie 19fe0a8b78 Btrfs: Switch the extent buffer rbtree into a radix tree
This patch reduces the CPU time spent in the extent buffer search by using the
radix tree instead of the rbtree and using the rcu lock instead of the spin
lock.

I did a quick test by the benchmark tool[1] and found the patch improve the
file creation/deletion performance problem that I have reported[2].

Before applying this patch:
Create files:
	Total files: 50000
	Total time: 0.971531
	Average time: 0.000019
Delete files:
	Total files: 50000
	Total time: 1.366761
	Average time: 0.000027

After applying this patch:
Create files:
	Total files: 50000
	Total time: 0.927455
	Average time: 0.000019
Delete files:
	Total files: 50000
	Total time: 1.292280
	Average time: 0.000026

[1] http://marc.info/?l=linux-btrfs&m=128212635122920&q=p3
[2] http://marc.info/?l=linux-btrfs&m=128212635122920&w=2

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-10-29 11:25:45 -04:00
Miao Xie 897ca6e9b4 Btrfs: restructure try_release_extent_buffer()
restructure try_release_extent_buffer() and write a function to release the
extent buffer. It will be used later.

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-10-29 11:25:45 -04:00
Christoph Hellwig 9c3a8ee8a1 writeback: remove writeback_inodes_wbc
This was just an odd wrapper around writeback_inodes_wb.  Removing this
also allows to get rid of the bdi member of struct writeback_control
which was rather out of place there.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2010-07-06 08:54:03 +02:00
Chris Mason 4845e44ffd Btrfs: rework O_DIRECT enospc handling
This changes O_DIRECT write code to mark extents as delalloc
while it is processing them.  Yan Zheng has reworked the
enospc accounting based on tracking delalloc extents and
this makes it much easier to track enospc in the O_DIRECT code.

There are a few space cases with the O_DIRECT code though,
it only sets the EXTENT_DELALLOC bits, instead of doing
EXTENT_DELALLOC | EXTENT_DIRTY | EXTENT_UPTODATE, because
we don't want to mess with clearing the dirty and uptodate
bits when things go wrong.  This is important because there
are no pages in the page cache, so any extent state structs
that we put in the tree won't get freed by releasepage.  We have
to clear them ourselves as the DIO ends.

With this commit, we reserve space at in btrfs_file_aio_write,
and then as each btrfs_direct_IO call progresses it sets
EXTENT_DELALLOC on the range.

btrfs_get_blocks_direct is responsible for clearing the delalloc
at the same time it drops the extent lock.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-05-25 21:52:08 -04:00
Chris Mason eaf25d933e Btrfs: use async helpers for DIO write checksumming
The async helper threads offload crc work onto all the
CPUs, and make streaming writes much faster.  This
changes the O_DIRECT write code to use them.  The only
small complication was that we need to pass in the
logical offset in the file for each bio, because we can't
find it in the bio's pages.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-05-25 10:34:58 -04:00
Josef Bacik 11c65dccf7 Btrfs: do aio_write instead of write
In order for AIO to work, we need to implement aio_write.  This patch converts
our btrfs_file_write to btrfs_aio_write.  I've tested this with xfstests and
nothing broke, and the AIO stuff magically started working.  Thanks,

Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-05-25 10:34:57 -04:00
Yan, Zheng 0ca1f7ceb1 Btrfs: Update metadata reservation for delayed allocation
Introduce metadata reservation context for delayed allocation
and update various related functions.

This patch also introduces EXTENT_FIRST_DELALLOC control bit for
set/clear_extent_bit. It tells set/clear_bit_hook whether they
are processing the first extent_state with EXTENT_DELALLOC bit
set. This change is important if set/clear_extent_bit involves
multiple extent_state.

Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-05-25 10:34:51 -04:00
Linus Torvalds 795d580bae Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable
* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable:
  Btrfs: add check for changed leaves in setup_leaf_for_split
  Btrfs: create snapshot references in same commit as snapshot
  Btrfs: fix small race with delalloc flushing waitqueue's
  Btrfs: use add_to_page_cache_lru, use __page_cache_alloc
  Btrfs: fix chunk allocate size calculation
  Btrfs: kill max_extent mount option
  Btrfs: fail to mount if we have problems reading the block groups
  Btrfs: check btrfs_get_extent return for IS_ERR()
  Btrfs: handle kmalloc() failure in inode lookup ioctl
  Btrfs: dereferencing freed memory
  Btrfs: Simplify num_stripes's calculation logical for __btrfs_alloc_chunk()
  Btrfs: Add error handle for btrfs_search_slot() in btrfs_read_chunk_tree()
  Btrfs: Remove unnecessary finish_wait() in wait_current_trans()
  Btrfs: add NULL check for do_walk_down()
  Btrfs: remove duplicate include in ioctl.c

Fix trivial conflict in fs/btrfs/compression.c due to slab.h include
cleanups.
2010-04-05 13:21:15 -07:00
Nick Piggin 28ecb60906 Btrfs: use add_to_page_cache_lru, use __page_cache_alloc
Pagecache pages should be allocated with __page_cache_alloc, so they
obey pagecache memory policies.

add_to_page_cache_lru is exported, so it should be used. Benefits over
using a private pagevec: neater code, 128 bytes fewer stack used, percpu
lru ordering is preserved, and finally don't need to flush pagevec
before returning so batching may be shared with other LRU insertions.

Signed-off-by: Nick Piggin <npiggin@suse.de>:
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-04-05 14:41:51 -04:00
Tejun Heo 5a0e3ad6af include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-30 22:02:32 +09:00
Josef Bacik 2ac55d41b5 Btrfs: cache the extent state everywhere we possibly can V2
This patch just goes through and fixes everybody that does

lock_extent()
blah
unlock_extent()

to use

lock_extent_bits()
blah
unlock_extent_cached()

and pass around a extent_state so we only have to do the searches once per
function.  This gives me about a 3 mb/s boots on my random write test.  I have
not converted some things, like the relocation and ioctl's, since they aren't
heavily used and the relocation stuff is in the middle of being re-written.  I
also changed the clear_extent_bit() to only unset the cached state if we are
clearing EXTENT_LOCKED and related stuff, so we can do things like this

lock_extent_bits()
clear delalloc bits
unlock_extent_cached()

without losing our cached state.  I tested this thoroughly and turned on
LEAK_DEBUG to make sure we weren't leaking extent states, everything worked out
fine.

Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-15 11:00:13 -04:00
Josef Bacik c2a128d28a Btrfs: cache extent state in find_delalloc_range
This patch makes us cache the extent state we find in find_delalloc_range since
we'll have to lock the extent later on in the function.  This will keep us from
re-searching for the rang when we try to lock the extent.

Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-15 11:00:13 -04:00
Chris Mason 4125bf761c Btrfs: finish read pages in the order they are submitted
The endio is done at reverse order of bio vectors.

That means for a sequential read, the page first submitted will finish
last in a bio. Considering we will do checksum (making cache hot) for
every page, this does introduce delay (and chance to squeeze cache used
soon) for pages submitted at the begining.

I don't observe obvious performance difference with below patch at my
simple test, but seems more natural to finish read in the order they are
submitted.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-15 11:00:12 -04:00
Eric Paris 6bef4d3171 Btrfs: use RB_ROOT to intialize rb_trees instead of setting rb_node to NULL
btrfs inialize rb trees in quite a number of places by settin rb_node =
NULL;  The problem with this is that 17d9ddc72f in the
linux-next tree adds a new field to that struct which needs to be NULL for
the new rbtree library code to work properly.  This patch uses RB_ROOT as
the intializer so all of the relevant fields will be NULL'd.  Without the
patch I get a panic.

Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-08 16:26:50 -05:00
Yan, Zheng f044ba7835 Btrfs: fix race between allocate and release extent buffer.
Increase extent buffer's reference count while holding the lock.
Otherwise it can race with try_release_extent_buffer.

Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-02-04 11:31:44 -05:00
Josef Bacik 32c00aff71 Btrfs: release delalloc reservations on extent item insertion
This patch fixes an issue with the delalloc metadata space reservation
code.  The problem is we used to free the reservation as soon as we
allocated the delalloc region.  The problem with this is if we are not
inserting an inline extent, we don't actually insert the extent item until
after the ordered extent is written out.  This patch does 3 things,

1) It moves the reservation clearing stuff into the ordered code, so when
we remove the ordered extent we remove the reservation.
2) It adds a EXTENT_DO_ACCOUNTING flag that gets passed when we clear
delalloc bits in the cases where we want to clear the metadata reservation
when we clear the delalloc extent, in the case that we do an inline extent
or we invalidate the page.
3) It adds another waitqueue to the space info so that when we start a fs
wide delalloc flush, anybody else who also hits that area will simply wait
for the flush to finish and then try to make their allocation.

This has been tested thoroughly to make sure we did not regress on
performance.

Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-10-08 15:21:10 -04:00
Chris Mason a791e35e12 Btrfs: cleanup extent_clear_unlock_delalloc flags
extent_clear_unlock_delalloc has a growing set of ugly parameters
that is very difficult to read and maintain.

This switches to a flag field and well named flag defines.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-10-08 15:11:49 -04:00
Josef Bacik 9ed74f2dba Btrfs: proper -ENOSPC handling
At the start of a transaction we do a btrfs_reserve_metadata_space() and
specify how many items we plan on modifying.  Then once we've done our
modifications and such, just call btrfs_unreserve_metadata_space() for
the same number of items we reserved.

For keeping track of metadata needed for data I've had to add an extent_io op
for when we merge extents.  This lets us track space properly when we are doing
sequential writes, so we don't end up reserving way more metadata space than
what we need.

The only place where the metadata space accounting is not done is in the
relocation code.  This is because Yan is going to be reworking that code in the
near future, so running btrfs-vol -b could still possibly result in a ENOSPC
related panic.  This patch also turns off the metadata_ratio stuff in order to
allow users to more efficiently use their disk space.

This patch makes it so we track how much metadata we need for an inode's
delayed allocation extents by tracking how many extents are currently
waiting for allocation.  It introduces two new callbacks for the
extent_io tree's, merge_extent_hook and split_extent_hook.  These help
us keep track of when we merge delalloc extents together and split them
up.  Reservations are handled prior to any actually dirty'ing occurs,
and then we unreserve after we dirty.

btrfs_unreserve_metadata_for_delalloc() will make the appropriate
unreservations as needed based on the number of reservations we
currently have and the number of extents we currently have.  Doing the
reservation outside of doing any of the actual dirty'ing lets us do
things like filemap_flush() the inode to try and force delalloc to
happen, or as a last resort actually start allocation on all delalloc
inodes in the fs.  This has survived dbench, fs_mark and an fsx torture
test.

Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-28 16:29:42 -04:00
Chris Mason 11ef160fda Btrfs: fix releasepage to avoid unlocking extents we haven't locked
During releasepage, we try to drop any extent_state structs for the
bye offsets of the page we're releaseing.  But the code was incorrectly
telling clear_extent_bit to delete the state struct unconditionallly.

Normally this would be fine because we have the page locked, but other
parts of btrfs will lock down an entire extent, the most common place
being IO completion.

releasepage was deleting the extent state without first locking the extent,
which may result in removing a state struct that another process had
locked down.  The fix here is to leave the NODATASUM and EXTENT_LOCKED
bits alone in releasepage.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-23 20:30:53 -04:00
Chris Mason 46562cec98 Btrfs: Fix test_range_bit for whole file extents
If test_range_bit finds an extent that goes all the way to (u64)-1, it
can incorrectly wrap the u64 instead of treaing it like the end of
the address space.

This just adds a check for the highest possible offset so we don't wrap.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-23 20:30:52 -04:00
Chris Mason 42daec299b Btrfs: fix errors handling cached state in set/clear_extent_bit
Both set and clear_extent_bit allow passing a cached
state struct to reduce rbtree search times.  clear_extent_bit
was improperly bypassing some of the checks around making sure
the extent state fields were correct for a given operation.

The fix used here (from Yan Zheng) is to use the hit_next
goto target instead of jumping all the way down to start clearing
bits without making sure the cached state was exactly correct
for the operation we were doing.

This also fixes up the setting of the start variable for both
ops in the case where we find an overlapping extent that
begins before the range we want to change.  In both cases
we were incorrectly going backwards from the original
requested change.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-23 20:30:52 -04:00
Chris Mason f85d7d6c8f Btrfs: properly honor wbc->nr_to_write changes
When btrfs fills a delayed allocation, it tries to increase
the wbc nr_to_write to cover a big part of allocation.  The
theory is that we're doing contiguous IO and writing a few
more blocks will save seeks overall at a very low cost.

The problem is that extent_write_cache_pages could ignore
the new higher nr_to_write if nr_to_write had already gone
down to zero.  We fix that by rechecking the nr_to_write
for every page that is processed in the pagevec.

This updates the math around bumping the nr_to_write value
to make sure we don't leave a tiny amount of IO hanging
around for the very end of a new extent.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-18 16:08:46 -04:00
Chris Mason 8b62b72b26 Btrfs: Use PagePrivate2 to track pages in the data=ordered code.
Btrfs writes go through delalloc to the data=ordered code.  This
makes sure that all of the data is on disk before the metadata
that references it.  The tracking means that we have to make sure
each page in an extent is fully written before we add that extent into
the on-disk btree.

This was done in the past by setting the EXTENT_ORDERED bit for the
range of an extent when it was added to the data=ordered code, and then
clearing the EXTENT_ORDERED bit in the extent state tree as each page
finished IO.

One of the reasons we had to do this was because sometimes pages are
magically dirtied without page_mkwrite being called.  The EXTENT_ORDERED
bit is checked at writepage time, and if it isn't there, our page become
dirty without going through the proper path.

These bit operations make for a number of rbtree searches for each page,
and can cause considerable lock contention.

This commit switches from the EXTENT_ORDERED bit to use PagePrivate2.
As pages go into the ordered code, PagePrivate2 is set on each one.
This is a cheap operation because we already have all the pages locked
and ready to go.

As IO finishes, the PagePrivate2 bit is cleared and the ordered
accoutning is updated for each page.

At writepage time, if the PagePrivate2 bit is missing, we go into the
writepage fixup code to handle improperly dirtied pages.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-11 13:31:07 -04:00
Chris Mason 9655d2982b Btrfs: use a cached state for extent state operations during delalloc
This changes the btrfs code to find delalloc ranges in the extent state
tree to use the new state caching code from set/test bit.  It reduces
one of the biggest causes of rbtree searches in the writeback path.

test_range_bit is also modified to take the cached state as a starting
point while searching.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-11 13:31:07 -04:00
Chris Mason d5550c6315 Btrfs: don't lock bits in the extent tree during writepage
At writepage time, we have the page locked and we have the
extent_map entry for this extent pinned in the extent_map tree.
So, the page can't go away and its mapping can't change.

There is no need for the extra extent_state lock bits during writepage.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-11 13:31:06 -04:00
Chris Mason 2c64c53d8d Btrfs: cache values for locking extents
Many of the btrfs extent state tree users follow the same pattern.
They lock an extent range in the tree, do some operation and then
unlock.

This translates to at least 2 rbtree searches, and maybe more if they
are doing operations on the extent state tree.  A locked extent
in the tree isn't going to be merged or changed, and so we can
safely return the extent state structure as a cached handle.

This changes set_extent_bit to give back a cached handle, and also
changes both set_extent_bit and clear_extent_bit to use the cached
handle if it is available.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-11 13:31:06 -04:00
Chris Mason 1edbb734b4 Btrfs: reduce CPU usage in the extent_state tree
Btrfs is currently mirroring some of the page state bits into
its extent state tree.  The goal behind this was to use it in supporting
blocksizes other than the page size.

But, we don't currently support that, and we're using quite a lot of CPU
on the rb tree and its spin lock.  This commit starts a series of
cleanups to reduce the amount of work done in the extent state tree as
part of each IO.

This commit:

* Adds the ability to lock an extent in the state tree and also set
other bits.  The idea is to do locking and delalloc in one call

* Removes the EXTENT_WRITEBACK and EXTENT_DIRTY bits.  Btrfs is using
a combination of the page bits and the ordered write code for this
instead.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-11 13:31:06 -04:00
Chris Mason e48c465bb3 Btrfs: Fix new state initialization order
As the extent state tree is manipulated, there are call backs
that are used to take extra actions when different state bits are set
or cleared.  One example of this is a counter for the total number
of delayed allocation bytes in a single inode and in the whole FS.

When new states are inserted, this callback is being done before we
properly setup the new state.  This hasn't caused problems before
because the lock bit was always done first, and the existing call backs
don't care about the lock bit.

This patch makes sure the state is properly setup before using the
callback, which is important for later optimizations that do more work
without using the lock bit.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-11 13:31:05 -04:00
Chris Mason 890871be85 Btrfs: switch extent_map to a rw lock
There are two main users of the extent_map tree.  The
first is regular file inodes, where it is evenly spread
between readers and writers.

The second is the chunk allocation tree, which maps blocks from
logical addresses to phyiscal ones, and it is 99.99% reads.

The mapping tree is a point of lock contention during heavy IO
workloads, so this commit switches things to a rw lock.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-11 13:31:05 -04:00
Chris Mason a97adc9fff Btrfs: use larger nr_to_write for larger extents
When btrfs fills a large delayed allocation extent, it is a good idea
to try and convince the write_cache_pages caller to go ahead and
write a good chunk of that extent.  The extra IO is basically free
because we know it is contiguous.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-11 13:31:04 -04:00
Chris Mason 40431d6c12 Btrfs: optimize set extent bit
The Btrfs set_extent_bit call currently searches the rbtree
every time it needs to find more extent_state objects to fill
the requested operation.

This adds a simple test with rb_next to see if the next object
in the tree was adjacent to the one we just found.  If so,
we skip the search and just use the next object.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-11 13:31:03 -04:00
Yan Zheng 5c939df56c btrfs: Fix set/clear_extent_bit for 'end == (u64)-1'
There are some 'start = state->end + 1;' like code in set_extent_bit
and clear_extent_bit. They overflow when end == (u64)-1.

Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 11:29:46 -04:00
Chris Mason b7967db75a Btrfs: remove #if 0 code
Btrfs had some old code sitting around under #if 0, this drops it.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-04-27 07:40:52 -04:00
Christoph Hellwig 9601e3f633 Btrfs: kill btrfs_cache_create
Just use kmem_cache_create directly.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-04-24 15:46:04 -04:00
Chris Mason 11c8349b4e Btrfs: fix oops on page->mapping->host during writepage
The extent_io writepage call updates the writepage index in the inode
as it makes progress.  But, it was doing the update after unlocking the page,
which isn't legal because page->mapping can't be trusted once the page
is unlocked.

This lead to an oops, especially common with compression turned on.  The
fix here is to update the writeback index before unlocking the page.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-04-20 15:53:09 -04:00
Chris Mason d313d7a31a Btrfs: add a priority queue to the async thread helpers
Btrfs is using WRITE_SYNC_PLUG to send down synchronous IOs with a
higher priority.  But, the checksumming helper threads prevent it
from being fully effective.

There are two problems.  First, a big queue of pending checksumming
will delay the synchronous IO behind other lower priority writes.  Second,
the checksumming uses an ordered async work queue.  The ordering makes sure
that IOs are sent to the block layer in the same order they are sent
to the checksumming threads.  Usually this gives us less seeky IO.

But, when we start mixing IO priorities, the lower priority IO can delay
the higher priority IO.

This patch solves both problems by adding a high priority list to the async
helper threads, and a new btrfs_set_work_high_prio(), which is used
to make put a new async work item onto the higher priority list.

The ordering is still done on high priority IO, but all of the high
priority bios are ordered separately from the low priority bios.  This
ordering is purely an IO optimization, it is not involved in data
or metadata integrity.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-04-20 15:53:08 -04:00
Chris Mason ffbd517d5a Btrfs: use WRITE_SYNC for synchronous writes
Part of reducing fsync/O_SYNC/O_DIRECT latencies is using WRITE_SYNC for
writes we plan on waiting on in the near future.  This patch
mirrors recent changes in other filesystems and the generic code to
use WRITE_SYNC when WB_SYNC_ALL is passed and to use WRITE_SYNC for
other latency critical writes.

Btrfs uses async worker threads for checksumming before the write is done,
and then again to actually submit the bios.  The bio submission code just
runs a per-device list of bios that need to be sent down the pipe.

This list is split into low priority and high priority lists so the
WRITE_SYNC IO happens first.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-04-20 15:53:08 -04:00
Heiko Carstens 93dbfad7ac Btrfs: fix __ucmpdi2 compile bug on 32 bit builds
We get this on 32 builds:

fs/built-in.o: In function `extent_fiemap':
(.text+0x1019f2): undefined reference to `__ucmpdi2'

Happens because of a switch statement with a 64 bit argument.
Convert this to an if statement to fix this.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-04-03 10:33:45 -04:00
Chris Mason b9473439d3 Btrfs: leave btree locks spinning more often
btrfs_mark_buffer dirty would set dirty bits in the extent_io tree
for the buffers it was dirtying.  This may require a kmalloc and it
was not atomic.  So, anyone who called btrfs_mark_buffer_dirty had to
set any btree locks they were holding to blocking first.

This commit changes dirty tracking for extent buffers to just use a flag
in the extent buffer.  Now that we have one and only one extent buffer
per page, this can be safely done without losing dirty bits along the way.

This also introduces a path->leave_spinning flag that callers of
btrfs_search_slot can use to indicate they will properly deal with a
path returned where all the locks are spinning instead of blocking.

Many of the btree search callers now expect spinning paths,
resulting in better btree concurrency overall.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-03-24 16:14:28 -04:00
Qinghuang Feng a48ddf08ba Btrfs: remove unused code in split_state()
These two lines are not used, remove them.

Signed-off-by: Qinghuang Feng <qhfeng.kernel@gmail.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-02-12 14:25:23 -05:00
Chris Mason 9b0d3ace33 Btrfs: don't return congestion in write_cache_pages as often
On fast devices that go from congested to uncongested very quickly, pdflush
is waiting too often in congestion_wait, and the FS is backing off to
easily in write_cache_pages.

For now, fix this on the btrfs side by only checking congestion after
some bios have already gone down.  Longer term a real fix is needed
for pdflush, but that is a larger project.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-02-04 09:33:00 -05:00
Chris Mason b4ce94de9b Btrfs: Change btree locking to use explicit blocking points
Most of the btrfs metadata operations can be protected by a spinlock,
but some operations still need to schedule.

So far, btrfs has been using a mutex along with a trylock loop,
most of the time it is able to avoid going for the full mutex, so
the trylock loop is a big performance gain.

This commit is step one for getting rid of the blocking locks entirely.
btrfs_tree_lock takes a spinlock, and the code explicitly switches
to a blocking lock when it starts an operation that can schedule.

We'll be able get rid of the blocking locks in smaller pieces over time.
Tracing allows us to find the most common cause of blocking, so we
can start with the hot spots first.

The basic idea is:

btrfs_tree_lock() returns with the spin lock held

btrfs_set_lock_blocking() sets the EXTENT_BUFFER_BLOCKING bit in
the extent buffer flags, and then drops the spin lock.  The buffer is
still considered locked by all of the btrfs code.

If btrfs_tree_lock gets the spinlock but finds the blocking bit set, it drops
the spin lock and waits on a wait queue for the blocking bit to go away.

Much of the code that needs to set the blocking bit finishes without actually
blocking a good percentage of the time.  So, an adaptive spin is still
used against the blocking bit to avoid very high context switch rates.

btrfs_clear_lock_blocking() clears the blocking bit and returns
with the spinlock held again.

btrfs_tree_unlock() can be called on either blocking or spinning locks,
it does the right thing based on the blocking bit.

ctree.c has a helper function to set/clear all the locked buffers in a
path as blocking.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-02-04 09:25:08 -05:00
Chris Mason 3935127c50 Btrfs: disable leak debugging checks in extent_io.c
extent_io.c has debugging code to report and free leaked extent_state
and extent_buffer objects at rmmod time.  This helps track down
leaks and it saves you from rebooting just to properly remove the
kmem_cache object.

But, the code runs under a fairly expensive spinlock and the checks to
see if it is currently enabled are not entirely consistent.  Some use
#ifdef and some #if.

This changes everything to #if and disables the leak checking.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-02-04 09:24:05 -05:00