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path: root/fs/btrfs/ordered-data.c
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2009-01-05Btrfs: Fix checkpatch.pl warningsChris Mason
There were many, most are fixed now. struct-funcs.c generates some warnings but these are bogus. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-12-08Btrfs: move data checksumming into a dedicated treeChris Mason
Btrfs stores checksums for each data block. Until now, they have been stored in the subvolume trees, indexed by the inode that is referencing the data block. This means that when we read the inode, we've probably read in at least some checksums as well. But, this has a few problems: * The checksums are indexed by logical offset in the file. When compression is on, this means we have to do the expensive checksumming on the uncompressed data. It would be faster if we could checksum the compressed data instead. * If we implement encryption, we'll be checksumming the plain text and storing that on disk. This is significantly less secure. * For either compression or encryption, we have to get the plain text back before we can verify the checksum as correct. This makes the raid layer balancing and extent moving much more expensive. * It makes the front end caching code more complex, as we have touch the subvolume and inodes as we cache extents. * There is potentitally one copy of the checksum in each subvolume referencing an extent. The solution used here is to store the extent checksums in a dedicated tree. This allows us to index the checksums by phyiscal extent start and length. It means: * The checksum is against the data stored on disk, after any compression or encryption is done. * The checksum is stored in a central location, and can be verified without following back references, or reading inodes. This makes compression significantly faster by reducing the amount of data that needs to be checksummed. It will also allow much faster raid management code in general. The checksums are indexed by a key with a fixed objectid (a magic value in ctree.h) and offset set to the starting byte of the extent. This allows us to copy the checksum items into the fsync log tree directly (or any other tree), without having to invent a second format for them. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-11-06Btrfs: Optimize compressed writeback and readsChris Mason
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>
2008-10-30Btrfs: Add fallocate support v2Yan Zheng
This patch updates btrfs-progs for fallocate support. fallocate is a little different in Btrfs because we need to tell the COW system that a given preallocated extent doesn't need to be cow'd as long as there are no snapshots of it. This leverages the -o nodatacow checks. Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
2008-10-30Btrfs: update nodatacow code v2Yan Zheng
This patch simplifies the nodatacow checker. If all references were created after the latest snapshot, then we can avoid COW safely. This patch also updates run_delalloc_nocow to do more fine-grained checking. Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
2008-10-29Btrfs: Add zlib compression supportChris Mason
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>
2008-10-03Btrfs: O_DIRECT writes via buffered writes + invaldiateChris Mason
This reworks the btrfs O_DIRECT write code a bit. It had always fallen back to buffered IO and done an invalidate, but needed to be updated for the data=ordered code. The invalidate wasn't actually removing pages because they were still inside an ordered extent. This also combines the O_DIRECT/O_SYNC paths where possible, and kicks off IO in the main btrfs_file_write loop to keep the pipe down the the disk full as we process long writes. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-29Btrfs: add and improve commentsChris Mason
This improves the comments at the top of many functions. It didn't dive into the guts of functions because I was trying to avoid merging problems with the new allocator and back reference work. extent-tree.c and volumes.c were both skipped, and there is definitely more work todo in cleaning and commenting the code. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26Btrfs: extent_map and data=ordered fixes for space balancingZheng Yan
* 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: Fix nodatacow for the new data=ordered modeYan Zheng
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Btrfs: Various small fixes.Yan Zheng
This trivial patch contains two locking fixes and a off by one fix. --- Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Btrfs: Fix the defragmention code and the block relocation code for data=orderedChris Mason
Before setting an extent to delalloc, the code needs to wait for pending ordered extents. Also, the relocation code needs to wait for ordered IO before scanning the block group again. This is because the extents are not removed until the IO for the new extents is finished Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Btrfs: Search data ordered extents first for checksums on readChris Mason
Checksum items are not inserted into the tree until all of the io from a given extent is complete. This means one dirty page from an extent may be written, freed, and then read again before the entire extent is on disk and the checksum item is inserted. The checksums themselves are stored in the ordered extent so they can be inserted in bulk when IO is complete. On read, if a checksum item isn't found, the ordered extents were being searched for a checksum record. This all worked most of the time, but the checksum insertion code tries to reduce the number of tree operations by pre-inserting checksum items based on i_size and a few other factors. This means the read code might find a checksum item that hasn't yet really been filled in. This commit changes things to check the ordered extents first and only dive into the btree if nothing was found. This removes the need for extra locking and is more reliable. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Btrfs: Take the csum mutex while reading checksumsChris Mason
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Btrfs: Fix some data=ordered related data corruptionsChris Mason
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: Data ordered fixesChris Mason
* In btrfs_delete_inode, wait for ordered extents after calling truncate_inode_pages. This is much faster, and more correct * Properly clear our the PageChecked bit everywhere we redirty the page. * Change the writepage fixup handler to lock the page range and check to see if an ordered extent had been inserted since the improperly dirtied page was discovered * Wait for ordered extents outside the transaction. This isn't required for locking rules but does improve transaction latencies * Reduce contention on the alloc_mutex by dropping it while incrementing refs on a node/leaf and while dropping refs on a leaf. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Fix btrfs_wait_ordered_extent_range to properly waitChris Mason
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Btrfs: Handle data checksumming on bios that span multiple ordered extentsChris Mason
Data checksumming is done right before the bio is sent down the IO stack, which means a single bio might span more than one ordered extent. In this case, the checksumming data is split between two ordered extents. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Btrfs: Cleanup and comment ordered-data.cChris Mason
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Btrfs: Don't pin pages in ram until the entire ordered extent is on disk.Chris Mason
Checksum items are not inserted until the entire ordered extent is on disk, but individual pages might be clean and available for reclaim long before the whole extent is on disk. In order to allow those pages to be freed, we need to be able to search the list of ordered extents to find the checksum that is going to be inserted in the tree. This way if the page needs to be read back in before the checksums are in the btree, we'll be able to verify the checksum on the page. This commit adds the ability to search the pending ordered extents for a given offset in the file, and changes btrfs_releasepage to allow ordered pages to be freed. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Btrfs: Update on disk i_size only after pending ordered extents are doneChris Mason
This changes the ordered data code to update i_size after the extent is on disk. An on disk i_size is maintained in the in-memory btrfs inode structures, and this is updated as extents finish. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Btrfs: New data=ordered implementationChris Mason
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: Add a per-inode csum mutex to avoid races creating csum itemsChris Mason
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Fix btrfs_del_ordered_inode to allow forcing the drop during unlinksChris Mason
This allows us to delete an unlinked inode with dirty pages from the list instead of forcing commit to write these out before deleting the inode. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25btrfs delete ordered inode handling fixMingming
Use btrfs_release_file instead of a put_inode call Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Btrfs: Fixes for 2.6.18 enterprise kernelsChris Mason
2.6.18 seems to get caught in an infinite loop when cancel_rearming_delayed_workqueue is called more than once, so this switches to cancel_delayed_work, which is arguably more correct. Also, balance_dirty_pages can run into problems with 2.6.18 based kernels because it doesn't have the per-bdi dirty limits. This avoids calling balance_dirty_pages on the btree inode unless there is actually something to balance, which is a good optimization in general. Finally there's a compile fix for ordered-data.h Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Btrfs: Throttle file_write when data=ordered is flushing the inodeChris Mason
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Btrfs: Fix data=ordered vs wait_on_inode deadlock on older kernelsChris Mason
Using ilookup5 during data=ordered writeback could deadlock on I_LOCK. This saves a pointer to the inode instead. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Btrfs: Run igrab on data=ordered inodes to prevent deadlocks during writeoutChris Mason
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Rework btrfs_drop_inode to avoid schedulingChris Mason
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25Btrfs: Add data=ordered supportChris Mason
This forces file data extents down the disk along with the metadata that references them. The current implementation is fairly simple, and just writes out all of the dirty pages in an inode before the commit. Signed-off-by: Chris Mason <chris.mason@oracle.com>