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path: root/fs/btrfs/extent_io.h
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2012-05-31Merge branch 'for-chris' of git://git.jan-o-sch.net/btrfs-unstable into ↵Chris Mason
for-linus Conflicts: fs/btrfs/ulist.h Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-05-30Btrfs: finish ordered extents in their own threadJosef Bacik
We noticed that the ordered extent completion doesn't really rely on having a page and that it could be done independantly of ending the writeback on a page. This patch makes us not do the threaded endio stuff for normal buffered writes and direct writes so we can end page writeback as soon as possible (in irq context) and only start threads to do the ordered work when it is actually done. Compression needs to be reworked some to take advantage of this as well, but atm it has to do a find_get_page in its endio handler so it must be done in its own thread. This makes direct writes quite a bit faster. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com>
2012-05-26Btrfs: dummy extent buffers for tree mod logJan Schmidt
The tree modification log needs two ways to create dummy extent buffers, once by allocating a fresh one (to rebuild an old root) and once by cloning an existing one (to make private rewind modifications) to it. Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
2012-04-18Btrfs: always store the mirror we read the eb fromJosef Bacik
A user reported a panic where we were trying to fix a bad mirror but the mirror number we were giving was 0, which is invalid. This is because we don't do the transid verification until after the read, so as far as the read code is concerned the read was a success. So instead store the mirror we read from so that if there is some failure post read we know which mirror to try next and which mirror needs to be fixed if we find a good copy of the block. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com>
2012-03-28Merge branch 'error-handling' into for-linusChris Mason
Conflicts: fs/btrfs/ctree.c fs/btrfs/disk-io.c fs/btrfs/extent-tree.c fs/btrfs/extent_io.c fs/btrfs/extent_io.h fs/btrfs/inode.c fs/btrfs/scrub.c Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-03-26Btrfs: deal with read errors on extent buffers differentlyJosef Bacik
Since we need to read and write extent buffers in their entirety we can't use the normal bio_readpage_error stuff since it only works on a per page basis. So instead make it so that if we see an io error in endio we just mark the eb as having an IO error and then in btree_read_extent_buffer_pages we will manually try other mirrors and then overwrite the bad mirror if we find a good copy. This works with larger than page size blocks. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-03-26Btrfs: ensure an entire eb is written at onceJosef Bacik
This patch simplifies how we track our extent buffers. Previously we could exit writepages with only having written half of an extent buffer, which meant we had to track the state of the pages and the state of the extent buffers differently. Now we only read in entire extent buffers and write out entire extent buffers, this allows us to simply set bits in our bflags to indicate the state of the eb and we no longer have to do things like track uptodate with our iotree. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-03-26Btrfs: introduce free_extent_buffer_staleJosef Bacik
Because btrfs cow's we can end up with extent buffers that are no longer necessary just sitting around in memory. So instead of evicting these pages, we could end up evicting things we actually care about. Thus we have free_extent_buffer_stale for use when we are freeing tree blocks. This will make it so that the ref for the eb being in the radix tree is dropped as soon as possible and then is freed when the refcount hits 0 instead of waiting to be released by releasepage. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com>
2012-03-26Btrfs: set page->private to the ebJosef Bacik
We spend a lot of time looking up extent buffers from pages when we could just store the pointer to the eb the page is associated with in page->private. This patch does just that, and it makes things a little simpler and reduces a bit of CPU overhead involved with doing metadata IO. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com>
2012-03-26Btrfs: allow metadata blocks larger than the page sizeChris Mason
A few years ago the btrfs code to support blocks lager than the page size was disabled to fix a few corner cases in the page cache handling. This fixes the code to properly support large metadata blocks again. Since current kernels will crash early and often with larger metadata blocks, this adds an incompat bit so that older kernels can't mount it. This also does away with different blocksizes for nodes and leaves. You get a single block size for all tree blocks. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-03-22btrfs: split extent_state opsJeff Mahoney
set_extent_bit can do exclusive locking but only when called by lock_extent*, Drop the exclusive bits argument except when called by lock_extent. Signed-off-by: Jeff Mahoney <jeffm@suse.com>
2012-03-22btrfs: drop gfp_t from lock_extentJeff Mahoney
lock_extent and unlock_extent are always called with GFP_NOFS, drop the argument and use GFP_NOFS consistently. Signed-off-by: Jeff Mahoney <jeffm@suse.com>
2012-03-22btrfs: return void in functions without error conditionsJeff Mahoney
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
2012-02-15btrfs: delalloc for page dirtied out-of-band in fixup workerJeff Mahoney
We encountered an issue that was easily observable on s/390 systems but could really happen anywhere. The timing just seemed to hit reliably on s/390 with limited memory. The gist is that when an unexpected set_page_dirty() happened, we'd run into the BUG() in btrfs_writepage_fixup_worker since it wasn't properly set up for delalloc. This patch does the following: - Performs the missing delalloc in the fixup worker - Allow the start hook to return -EBUSY which informs __extent_writepage that it should mark the page skipped and not to redirty it. This is required since the fixup worker can fail with -ENOSPC and the page will have already been redirtied. That causes an Oops in drop_outstanding_extents later. Retrying the fixup worker could lead to an infinite loop. Deferring the page redirty also saves us some cycles since the page would be stuck in a resubmit-redirty loop until the fixup worker completes. It's not harmful, just wasteful. - If the fixup worker fails, we mark the page and mapping as errored, and end the writeback, similar to what we would do had the page actually been submitted to writeback. Signed-off-by: Jeff Mahoney <jeffm@suse.com>
2012-01-04Btrfs: add nested locking mode for pathsArne Jansen
This patch adds the possibilty to read-lock an extent even if it is already write-locked from the same thread. btrfs_find_all_roots() needs this capability. Signed-off-by: Arne Jansen <sensille@gmx.net> Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
2011-11-20btrfs: mirror_num should be int, not u64Jan Schmidt
My previous patch introduced some u64 for failed_mirror variables, this one makes it consistent again. Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-11-06Merge git://git.jan-o-sch.net/btrfs-unstable into integrationChris Mason
Conflicts: fs/btrfs/Makefile fs/btrfs/extent_io.c fs/btrfs/extent_io.h fs/btrfs/scrub.c Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-11-06Merge branch 'for-chris' of git://github.com/sensille/linux into integrationChris Mason
Conflicts: fs/btrfs/ctree.h Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-11-06Btrfs: make sure to flush queued bios if write_cache_pages waitsChris Mason
write_cache_pages tries to build up a large bio to stuff down the pipe. But if it needs to wait for a page lock, it needs to make sure and send down any pending writes so we don't deadlock with anyone who has the page lock and is waiting for writeback of things inside the bio. Dave Sterba triggered this as a deadlock between the autodefrag code and the extent write_cache_pages Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-10-19Btrfs: stop using write_one_pageJosef Bacik
While looking for a performance regression a user was complaining about, I noticed that we had a regression with the varmail test of filebench. This was introduced by 0d10ee2e6deb5c8409ae65b970846344897d5e4e which keeps us from calling writepages in writepage. This is a correct change, however it happens to help the varmail test because we write out in larger chunks. This is largly to do with how we write out dirty pages for each transaction. If you run filebench with load varmail set $dir=/mnt/btrfs-test run 60 prior to this patch you would get ~1420 ops/second, but with the patch you get ~1200 ops/second. This is a 16% decrease. So since we know the range of dirty pages we want to write out, don't write out in one page chunks, write out in ranges. So to do this we call filemap_fdatawrite_range() on the range of bytes. Then we convert the DIRTY extents to NEED_WAIT extents. When we then call btrfs_wait_marked_extents() we only have to filemap_fdatawait_range() on that range and clear the NEED_WAIT extents. This doesn't get us back to our original speeds, but I've been seeing ~1380 ops/second, which is a <5% regression as opposed to a >15% regression. That is acceptable given that the original commit greatly reduces our latency to begin with. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com>
2011-10-19Btrfs: introduce convert_extent_bitJosef Bacik
If I have a range where I know a certain bit is and I want to set it to another bit the only option I have is to call set and then clear bit, which will result in 2 tree searches. This is inefficient, so introduce convert_extent_bit which will go through and set the bit I want and clear the old bit I don't want. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com>
2011-10-02btrfs: add READAHEAD extent buffer flagArne Jansen
Add a READAHEAD extent buffer flag. Add a function to trigger a read with this flag set. Changes v2: - use extent buffer flags instead of extent state flags Changes v5: - adapt to changed read_extent_buffer_pages interface - don't return eb from reada_tree_block_flagged if it has CORRUPT flag set Signed-off-by: Arne Jansen <sensille@gmx.net>
2011-10-02btrfs: add an extra wait mode to read_extent_buffer_pagesArne Jansen
read_extent_buffer_pages currently has two modes, either trigger a read without waiting for anything, or wait for the I/O to finish. The former also bails when it's unable to lock the page. This patch now adds an additional parameter to allow it to block on page lock, but don't wait for completion. Changes v5: - merge the 2 wait parameters into one and define WAIT_NONE, WAIT_COMPLETE and WAIT_PAGE_LOCK Change v6: - fix bug introduced in v5 Signed-off-by: Arne Jansen <sensille@gmx.net>
2011-09-29btrfs: Moved repair code from inode.c to extent_io.cJan Schmidt
The raid-retry code in inode.c can be generalized so that it works for metadata as well. Thus, this patch moves it to extent_io.c and makes the raid-retry code a raid-repair code. Repair works that way: Whenever a read error occurs and we have more mirrors to try, note the failed mirror, and retry another. If we find a good one, check if we did note a failure earlier and if so, do not allow the read to complete until after the bad sector was written with the good data we just fetched. As we have the extent locked while reading, no one can change the data in between. Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
2011-09-29btrfs scrub: add fixup code for errors on nodatasum filesJan Schmidt
This removes a FIXME comment and introduces the first part of nodatasum fixup: It gets the corresponding inode for a logical address and triggers a regular readpage for the corrupted sector. Once we have on-the-fly error correction our error will be automatically corrected. The correction code is expected to clear the newly introduced EXTENT_DAMAGED flag, making scrub report that error as "corrected" instead of "uncorrectable" eventually. Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
2011-09-29btrfs: add mirror_num to extent_read_full_pageJan Schmidt
Currently, extent_read_full_page always assumes we are trying to read mirror 0, which generally is the best we can do. To add flexibility, pass it as a parameter. This will be needed by scrub fixup code. Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
2011-08-01Btrfs: remove unused members from struct extent_stateXiao Guangrong
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>
2011-08-01btrfs: Make extent-io callbacks that never fail return voidJeff Mahoney
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>
2011-07-27Btrfs: switch the btrfs tree locks to reader/writerChris Mason
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>
2011-07-27Btrfs: stop using highmem for extent_buffersChris Mason
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>
2011-06-10btrfs: remove 64bit alignment padding to allow extent_buffer to fit into one ↵richard kennedy
fewer cacheline Reorder extent_buffer to remove 8 bytes of alignment padding on 64 bit builds. This shrinks its size to 128 bytes allowing it to fit into one fewer cache lines and allows more objects per slab in its kmem_cache. slabinfo extent_buffer reports :- before:- Sizes (bytes) Slabs ---------------------------------- Object : 136 Total : 123 SlabObj: 136 Full : 121 SlabSiz: 4096 Partial: 0 Loss : 0 CpuSlab: 2 Align : 8 Objects: 30 after :- Object : 128 Total : 4 SlabObj: 128 Full : 2 SlabSiz: 4096 Partial: 0 Loss : 0 CpuSlab: 2 Align : 8 Objects: 32 Signed-off-by: Richard Kennedy <richard@rsk.demon.co.uk> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-05-06btrfs: remove all unused functionsDavid Sterba
Remove static and global declarations and/or definitions. Reduces size of btrfs.ko by ~3.4kB. text data bss dec hex filename 402081 7464 200 409745 64091 btrfs.ko.base 398620 7144 200 405964 631cc btrfs.ko.remove-all Signed-off-by: David Sterba <dsterba@suse.cz>
2011-05-04btrfs: remove unused function prototypesDavid Sterba
function prototypes without a body Signed-off-by: David Sterba <dsterba@suse.cz>
2011-05-02btrfs: drop gfp parameter from alloc_extent_bufferDavid Sterba
pass GFP_NOFS directly to kmem_cache_alloc Signed-off-by: David Sterba <dsterba@suse.cz>
2011-05-02btrfs: drop gfp parameter from find_extent_bufferDavid Sterba
pass GFP_NOFS directly to kmem_cache_alloc Signed-off-by: David Sterba <dsterba@suse.cz>
2011-05-02btrfs: drop unused argument from extent_io_tree_initDavid Sterba
all callers pass GFP_NOFS, but the GFP mask argument is not used in the function; GFP_ATOMIC is passed to radix tree initialization and it's the only correct one, since we're using the preload/insert mechanism of radix tree. Let's drop the gfp mask from btrfs function, this will not change behaviour. Signed-off-by: David Sterba <dsterba@suse.cz>
2011-05-02btrfs: rename variables clashing with global function namesDavid Sterba
reported by gcc -Wshadow: page_index, page_offset, new_inode, dev_name Signed-off-by: David Sterba <dsterba@suse.cz>
2011-04-11btrfs: using cached extent_state in set/unlock combinationsArne Jansen
In several places the sequence (set_extent_uptodate, unlock_extent) is used. This leads to a duplicate lookup of the extent state. This patch lets set_extent_uptodate return a cached extent_state which can be passed to unlock_extent_cached. The occurences of the above sequences are updated to use the cache. Only end_bio_extent_readpage is updated that it first gets a cached state to pass it to the readpage_end_io_hook as the prototype requested and is later on being used for set/unlock. Signed-off-by: Arne Jansen <sensille@gmx.net> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-03-17Btrfs: check items for correctness as we searchJosef Bacik
Currently if we have corrupted items things will blow up in spectacular ways. So as we read in blocks and they are leaves, check the entire leaf to make sure all of the items are correct and point to valid parts in the leaf for the item data the are responsible for. If the item is corrupt we will kick back EIO and not read any of the copies since they are likely to not be correct either. This will catch generic corruptions, it will be up to the individual callers of btrfs_search_slot to make sure their items are right. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com>
2011-02-23Btrfs: fix fiemap bugs with delallocChris Mason
The Btrfs fiemap code wasn't properly returning delalloc extents, so applications that trust fiemap to decide if there are holes in the file see holes instead of delalloc. This reworks the btrfs fiemap code, adding a get_extent helper that searches for delalloc ranges and also adding a helper for extent_fiemap that skips past holes in the file. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-12-22btrfs: Allow to add new compression algorithmLi Zefan
Make the code aware of compression type, instead of always assuming zlib compression. Also make the zlib workspace function as common code for all compression types. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
2010-11-21btrfs: cleanup duplicate bio allocating functionsMiao Xie
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>
2010-10-29Btrfs: Switch the extent buffer rbtree into a radix treeMiao Xie
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>
2010-05-25Btrfs: rework O_DIRECT enospc handlingChris Mason
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>
2010-05-25Btrfs: use async helpers for DIO write checksummingChris Mason
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>
2010-05-25Btrfs: Update metadata reservation for delayed allocationYan, Zheng
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>
2010-03-15Btrfs: cache the extent state everywhere we possibly can V2Josef Bacik
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>
2009-10-08Btrfs: release delalloc reservations on extent item insertionJosef Bacik
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>
2009-10-08Btrfs: cleanup extent_clear_unlock_delalloc flagsChris Mason
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>
2009-09-28Btrfs: proper -ENOSPC handlingJosef Bacik
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>