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path: root/fs/btrfs/extent_io.h
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2010-03-15Btrfs: cache the extent state everywhere we possibly can V2Josef Bacik1-3/+7
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 Bacik1-0/+2
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 Mason1-6/+10
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 Bacik1-2/+11
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>
2009-09-11Btrfs: Use PagePrivate2 to track pages in the data=ordered code.Chris Mason1-5/+4
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>
2009-09-11Btrfs: use a cached state for extent state operations during delallocChris Mason1-1/+1
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>
2009-09-11Btrfs: cache values for locking extentsChris Mason1-2/+3
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>
2009-09-11Btrfs: reduce CPU usage in the extent_state treeChris Mason1-0/+2
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>
2009-03-24Btrfs: leave btree locks spinning more oftenChris Mason1-0/+3
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>
2009-02-04Btrfs: Change btree locking to use explicit blocking pointsChris Mason1-2/+14
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>
2009-01-21Btrfs: fiemap supportYehuda Sadeh1-0/+2
Now that bmap support is gone, this is the only way to get extent mappings for userland. These are still not valid for IO, but they can tell us if a file has holes or how much fragmentation there is. Signed-off-by: Yehuda Sadeh <yehuda@hq.newdream.net>
2008-12-12Btrfs: fix nodatasum handling in balancing codeYan Zheng1-0/+1
Checksums on data can be disabled by mount option, so it's possible some data extents don't have checksums or have invalid checksums. This causes trouble for data relocation. This patch contains following things to make data relocation work. 1) make nodatasum/nodatacow mount option only affects new files. Checksums and COW on data are only controlled by the inode flags. 2) check the existence of checksum in the nodatacow checker. If checksums exist, force COW the data extent. This ensure that checksum for a given block is either valid or does not exist. 3) update data relocation code to properly handle the case of checksum missing. Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
2008-11-06Btrfs: Optimize compressed writeback and readsChris Mason1-3/+10
When reading compressed extents, try to put pages into the page cache for any pages covered by the compressed extent that readpages didn't already preload. Add an async work queue to handle transformations at delayed allocation processing time. Right now this is just compression. The workflow is: 1) Find offsets in the file marked for delayed allocation 2) Lock the pages 3) Lock the state bits 4) Call the async delalloc code The async delalloc code clears the state lock bits and delalloc bits. It is important this happens before the range goes into the work queue because otherwise it might deadlock with other work queue items that try to lock those extent bits. The file pages are compressed, and if the compression doesn't work the pages are written back directly. An ordered work queue is used to make sure the inodes are written in the same order that pdflush or writepages sent them down. This changes extent_write_cache_pages to let the writepage function update the wbc nr_written count. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29Btrfs: nuke fs wide allocation mutex V2Josef Bacik1-0/+2
This patch removes the giant fs_info->alloc_mutex and replaces it with a bunch of little locks. There is now a pinned_mutex, which is used when messing with the pinned_extents extent io tree, and the extent_ins_mutex which is used with the pending_del and extent_ins extent io trees. The locking for the extent tree stuff was inspired by a patch that Yan Zheng wrote to fix a race condition, I cleaned it up some and changed the locking around a little bit, but the idea remains the same. Basically instead of holding the extent_ins_mutex throughout the processing of an extent on the extent_ins or pending_del trees, we just hold it while we're searching and when we clear the bits on those trees, and lock the extent for the duration of the operations on the extent. Also to keep from getting hung up waiting to lock an extent, I've added a try_lock_extent so if we cannot lock the extent, move on to the next one in the tree and we'll come back to that one. I have tested this heavily and it does not appear to break anything. This has to be applied on top of my find_free_extent redo patch. I tested this patch on top of Yan's space reblancing code and it worked fine. The only thing that has changed since the last version is I pulled out all my debugging stuff, apparently I forgot to run guilt refresh before I sent the last patch out. Thank you, Signed-off-by: Josef Bacik <jbacik@redhat.com>
2008-10-29Btrfs: Add zlib compression supportChris Mason1-3/+14
This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26Btrfs: extent_map and data=ordered fixes for space balancingZheng Yan1-0/+1
* Add an EXTENT_BOUNDARY state bit to keep the writepage code from merging data extents that are in the process of being relocated. This allows us to do accounting for them properly. * The balancing code relocates data extents indepdent of the underlying inode. The extent_map code was modified to properly account for things moving around (invalidating extent_map caches in the inode). * Don't take the drop_mutex in the create_subvol ioctl. It isn't required. * Fix walking of the ordered extent list to avoid races with sys_unlink * Change the lock ordering rules. Transaction start goes outside the drop_mutex. This allows btrfs_commit_transaction to directly drop the relocation trees. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Btrfs: Tree logging fixesChris Mason1-0/+1
* Pin down data blocks to prevent them from being reallocated like so: trans 1: allocate file extent trans 2: free file extent trans 3: free file extent during old snapshot deletion trans 3: allocate file extent to new file trans 3: fsync new file Before the tree logging code, this was legal because the fsync would commit the transation that did the final data extent free and the transaction that allocated the extent to the new file at the same time. With the tree logging code, the tree log subtransaction can commit before the transaction that freed the extent. If we crash, we're left with two different files using the extent. * Don't wait in start_transaction if log replay is going on. This avoids deadlocks from iput while we're cleaning up link counts in the replay code. * Don't deadlock in replay_one_name by trying to read an inode off the disk while holding paths for the directory * Hold the buffer lock while we mark a buffer as written. This closes a race where someone is changing a buffer while we write it. They are supposed to mark it dirty again after they change it, but this violates the cow rules. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Btrfs: Fix some data=ordered related data corruptionsChris Mason1-1/+0
Stress testing was showing data checksum errors, most of which were caused by a lookup bug in the extent_map tree. The tree was caching the last pointer returned, and searches would check the last pointer first. But, search callers also expect the search to return the very first matching extent in the range, which wasn't always true with the last pointer usage. For now, the code to cache the last return value is just removed. It is easy to fix, but I think lookups are rare enough that it isn't required anymore. This commit also replaces do_sync_mapping_range with a local copy of the related functions. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Btrfs: Use a mutex in the extent buffer for tree block lockingChris Mason1-0/+1
This replaces the use of the page cache lock bit for locking, which wasn't suitable for block size < page size and couldn't be used recursively. The mutexes alone don't fix either problem, but they are the first step. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Btrfs: Index extent buffers in an rbtreeChris Mason1-7/+4
Before, extent buffers were a temporary object, meant to map a number of pages at once and collect operations on them. But, a few extra fields have crept in, and they are also the best place to store a per-tree block lock field as well. This commit puts the extent buffers into an rbtree, and ensures a single extent buffer for each tree block. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Btrfs: Use async helpers to deal with pages that have been improperly dirtiedChris Mason1-0/+1
Higher layers sometimes call set_page_dirty without asking the filesystem to help. This causes many problems for the data=ordered and cow code. This commit detects pages that haven't been properly setup for IO and kicks off an async helper to deal with them. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Btrfs: New data=ordered implementationChris Mason1-1/+13
The old data=ordered code would force commit to wait until all the data extents from the transaction were fully on disk. This introduced large latencies into the commit and stalled new writers in the transaction for a long time. The new code changes the way data allocations and extents work: * When delayed allocation is filled, data extents are reserved, and the extent bit EXTENT_ORDERED is set on the entire range of the extent. A struct btrfs_ordered_extent is allocated an inserted into a per-inode rbtree to track the pending extents. * As each page is written EXTENT_ORDERED is cleared on the bytes corresponding to that page. * When all of the bytes corresponding to a single struct btrfs_ordered_extent are written, The previously reserved extent is inserted into the FS btree and into the extent allocation trees. The checksums for the file data are also updated. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Btrfs: Handle write errors on raid1 and raid10Chris Mason1-1/+6
When duplicate copies exist, writes are allowed to fail to one of those copies. This changeset includes a few changes that allow the FS to continue even when some IOs fail. It also adds verification of the parent generation number for btree blocks. This generation is stored in the pointer to a block, and it ensures that missed writes to are detected. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Btrfs: Don't drop extent_map cache during releasepage on the btree inodeChris Mason1-0/+3
The btree inode should only have a single extent_map in the cache, it doesn't make sense to ever drop it. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Btrfs: Create a work queue for bio writesChris Mason1-2/+3
This allows checksumming to happen in parallel among many cpus, and keeps us from bogging down pdflush with the checksumming code. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Btrfs: Handle checksumming errors while reading data blocksChris Mason1-0/+3
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Btrfs: Retry metadata reads in the face of checksum failuresChris Mason1-2/+3
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Btrfs: Do metadata checksums for reads via a workqueueChris Mason1-1/+3
Before, metadata checksumming was done by the callers of read_tree_block, which would set EXTENT_CSUM bits in the extent tree to show that a given range of pages was already checksummed and didn't need to be verified again. But, those bits could go away via try_to_releasepage, and the end result was bogus checksum failures on pages that never left the cache. The new code validates checksums when the page is read. It is a little tricky because metadata blocks can span pages and a single read may end up going via multiple bios. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Btrfs: Add additional debugging for metadata checksum failuresChris Mason1-0/+2
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Btrfs: Add leak debugging for extent_buffer and extent_stateChris Mason1-1/+2
This also fixes one leak around the super block when failing to mount the FS. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Btrfs: Bring back mount -o ssd optimizationsChris Mason1-0/+2
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Btrfs: Add support for multiple devices per filesystemChris Mason1-1/+1
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Btrfs: checksum file data at bio submission time instead of during writepageChris Mason1-0/+1
When we checkum file data during writepage, the checksumming is done one page at a time, making it difficult to do bulk metadata modifications to insert checksums for large ranges of the file at once. This patch changes btrfs to checksum on a per-bio basis instead. The bios are checksummed before they are handed off to the block layer, so each bio is contiguous and only has pages from the same inode. Checksumming on a bio basis allows us to insert and modify the file checksum items in large groups. It also allows the checksumming to be done more easily by async worker threads. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Btrfs: Allocator improvementsChris Mason1-0/+11
Reduce CPU time searching for free blocks by optimizing find_first_extent_bit Fix find_free_extent to make better use of the last_alloc hint. Before it was often finding blocks just before the hint. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Btrfs: Create larger bios for btree blocksChris Mason1-1/+2
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Btrfs: Add a lookup cache to the extent state treeChris Mason1-0/+1
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Btrfs: Enable delalloc accountingChris Mason1-2/+2
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Btrfs: Do delalloc accounting via hooks in the extent_state codeChris Mason1-0/+4
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Btrfs: extent_io and extent_state optimizationsChris Mason1-5/+10
The end_bio routines are changed to take a pointer to the extent state struct, and the state tree is walked in order to set/clear appropriate bits as IO completes. This greatly reduces the number of rbtree searches done by the end_bio handlers, and reduces lock contention. The extent_io releasepage function is changed to avoid expensive searches for locked state. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Btrfs: Split the extent_map code into two partsChris Mason1-0/+193
There is now extent_map for mapping offsets in the file to disk and extent_io for state tracking, IO submission and extent_bufers. The new extent_map code shifts from [start,end] pairs to [start,len], and pushes the locking out into the caller. This allows a few performance optimizations and is easier to use. A number of extent_map usage bugs were fixed, mostly with failing to remove extent_map entries when changing the file. Signed-off-by: Chris Mason <chris.mason@oracle.com>