- 09 Oct, 2008 3 commits
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Yan Zheng authored
Due to the optimization for truncate, tree leaves only containing checksum items can be deleted without being COW'ed first. This causes reference cache misses. The way to fix the miss is create cache entries for tree leaves only contain checksum. This patch also fixes a -EEXIST issue in shared reference cache. Signed-off-by:Yan Zheng <zheng.yan@oracle.com>
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Yan Zheng authored
The offset field in struct btrfs_extent_ref records the position inside file that file extent is referenced by. In the new back reference system, tree leaves holding references to file extent are recorded explicitly. We can scan these tree leaves very quickly, so the offset field is not required. This patch also makes the back reference system check the objectid when extents are in deleting. Signed-off-by: -
Yan Zheng authored
This patch makes btrfs count space allocated to file in bytes instead of 512 byte sectors. Everything else in btrfs uses a byte count instead of sector sizes or blocks sizes, so this fits better. Signed-off-by:
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- 03 Oct, 2008 3 commits
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Chris Mason authored
On 32 bit machines without CONFIG_LBD, the bi_sector field is only 32 bits. Btrfs needs to cast it before shifting up, or we end up doing IO into the wrong place. Signed-off-by:Chris Mason <chris.mason@oracle.com>
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Chris Mason authored
The tree logging code was trying to separate tree log allocations from normal metadata allocations to improve writeback patterns during an fsync. But, the code was not effective and ended up just mixing tree log blocks with regular metadata. That seems to be working fairly well, so the last_log_alloc code can be removed. Signed-off-by: -
Chris Mason authored
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:
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- 01 Oct, 2008 4 commits
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Chris Mason authored
Checksum items take up a significant portion of the metadata for large files. It is possible to avoid reading them during truncates by checking the keys in the higher level nodes. If a given leaf is followed by another leaf where the lowest key is a checksum item from the same file, we know we can safely delete the leaf without reading it. For a 32GB file on a 6 drive raid0 array, Btrfs needs 8s to delete the file with a cold cache. It is read bound during the run. With this change, Btrfs is able to delete the file in 0.5s Signed-off-by: -
Josef Bacik authored
This fixes a deadlock that happens between the alloc_mutex and chunk_mutex. Process A comes in, decides to do a do_chunk_alloc, which takes the chunk_mutex, and is holding the alloc_mutex because the only way you get to do_chunk_alloc is by holding the alloc_mutex. btrfs_alloc_chunk does its thing and goes to insert a new item, which results in a cow of the block. We get into del_pending_extents from there, where if we need to be rescheduled we drop the alloc_mutex and schedule. At this point process B comes in to do an allocation and gets the alloc_mutex, and because process A did not do the chunk allocation completely it thinks its a good time to do a chunk allocation as well, and hangs on the chunk_mutex. Process A wakes up and tries to take the alloc_mutex and cannot. The way to fix this is do a mutex_trylock() on chunk_mutex. If we return 0 we didn't get the lock, and if this is just a "hey it may be a good time to allocate a chunk" then we just exit. If we are trying to force an allocation then we reschedule and keep trying to acquire the chunk_mutex. If once we acquire it the space is already full then we can just exit, otherwise we can continue with the chunk allocation. Thank you, Signed-off-by:Josef Bacik <jbacik@redhat.com>
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Jim Meyering authored
Signed-off-by: -
Jim Meyering authored
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- 30 Sep, 2008 2 commits
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Chris Mason authored
When reading in block groups, a global mask of the available raid policies should be adjusted based on the types of block groups found on disk. This global mask is then used to decide which raid policy to use for new block groups. The recent allocator changes dropped the call that updated the global mask, making all the block groups allocated at run time single striped onto a single drive. This also fixes the async worker threads to set any thread that uses the requeue mechanism as busy. This allows us to avoid blocking on get_request_wait for the async bio submission threads. Signed-off-by: -
Josef Bacik authored
This patch fixes a problem where we end up seeking too much when *last_ptr is valid. This happens because btrfs_lookup_first_block_group only returns a block group that starts on or after the given search start, so if the search_start is in the middle of a block group it will return the block group after the given search_start, which is suboptimal. This patch fixes that by doing a btrfs_lookup_block_group, which will return the block group that contains the given search start. If we fail to find a block group, we fall back on btrfs_lookup_first_block_group so we can find the next block group, not sure if this is absolutely needed, but better safe than sorry. Also if we can't find the block group that we need, or it happens to not be of the right type, we need to add empty_cluster since *last_ptr could point to a mismatched block group, which means we need to start over with empty_cluster added to total needed. Thank you, Signed-off-by:
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- 29 Sep, 2008 3 commits
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Chris Mason authored
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 authored
btrfs_add_leaf_ref was doing checks on the objects it found in the rbtree to make sure they were properly linked into the tree. But, the field it was checking can be safely changed outside of the tree spin lock. The WARN_ON was for debugging the initial implementation and can be safely removed. Signed-off-by: -
Chris Mason authored
btrfs-vol -a /dev/xxx will zero the first and last two MB of the device. The kernel code needs to wait for this IO to finish before it adds the device. btrfs metadata IO does not happen through the block device inode. A separate address space is used, allowing the zero filled buffer heads in the block device inode to be written to disk after FS metadata starts going down to the disk via the btrfs metadata inode. The end result is zero filled metadata blocks after adding new devices into the filesystem. The fix is a simple filemap_write_and_wait on the block device inode before actually inserting it into the pool of available devices. Signed-off-by:
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- 26 Sep, 2008 4 commits
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Zheng Yan authored
This patch updates the space balancing code to utilize the new backref format. Before, btrfs-vol -b would break any COW links on data blocks or metadata. This was slow and caused the amount of space used to explode if a large number of snapshots were present. The new code can keeps the sharing of all data extents and most of the tree blocks. To maintain the sharing of data extents, the space balance code uses a seperate inode hold data extent pointers, then updates the references to point to the new location. To maintain the sharing of tree blocks, the space balance code uses reloc trees to relocate tree blocks in reference counted roots. There is one reloc tree for each subvol, and all reloc trees share same root key objectid. Reloc trees are snapshots of the latest committed roots of subvols (root->commit_root). To relocate a tree block referenced by a subvol, there are two steps. COW the block through subvol's reloc tree, then update block pointer in the subvol to point to the new block. Since all reloc trees share same root key objectid, doing special handing for tree blocks owned by them is easy. Once a tree block has been COWed in one reloc tree, we can use the resulting new block directly when the same block is required to COW again through other reloc trees. In this way, relocated tree blocks are shared between reloc trees, so they are also shared between subvols. Signed-off-by: -
Zheng Yan authored
* 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: -
Zheng Yan authored
Btrfs has a cache of reference counts in leaves, allowing it to avoid reading tree leaves while deleting snapshots. To reduce contention with multiple subvolumes, this cache is private to each subvolume. This patch adds shared reference cache support. The new space balancing code plays with multiple subvols at the same time, So the old per-subvol reference cache is not well suited. Signed-off-by: -
Zheng Yan authored
* Reserved extent accounting: reserved extents have been allocated in the rbtrees that track free space but have not been allocated on disk. They were never properly accounted for in the past, making it hard to know how much space was really free. * btrfs_find_block_group used to return NULL for block groups that had been removed by the space balancing code. This made it hard to account for space during the final stages of a balance run. Signed-off-by:
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- 25 Sep, 2008 21 commits
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Chris Mason authored
Btrfs metadata writeback is fairly expensive. Once a tree block is written it must be cowed before it can be changed again. The btree writepages code has a threshold based on a count of dirty btree bytes which is updated as IO is sent out. This changes btree_writepages to skip the writeout if there are less than 32MB of dirty bytes from the btrees, improving performance across many workloads. Signed-off-by: -
Chris Mason authored
The code to free block groups needs to drop the space info spin lock before calling btrfs_remove_free_space_cache (which can schedule). This is safe because at unmount time, nobody else is going to play with the block groups. Signed-off-by: -
Chris Mason authored
Btrfs had compatibility code for kernels back to 2.6.18. These have been removed, and will be maintained in a separate backport git tree from now on. Signed-off-by: -
Chris Mason authored
After a crash, the tree log code uses btrfs_alloc_logged_extent to record allocations of data extents that it finds in the log tree. These come in basically random order, which does not fit how btrfs_remove_free_space() expects to be called. btrfs_remove_free_space was changed to support recording an extent allocation in the middle of a region of free space. Signed-off-by: -
Chris Mason authored
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Chris Mason authored
btrfs had magic to put the chagneset id into a printk on module load. This removes that from the Makefile and hardcodes the printk to print "Btrfs" Signed-off-by: -
Chris Mason authored
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Chris Mason authored
The code to update the on disk i_size happens before the ordered_extent record is removed. So, it is possible for multiple ordered_extent completion routines to run at the same time, and to find each other in the ordered tree. The end result is they both decide not to update disk_i_size, leaving it too small. This temporary fix just puts the updates inside the extent_mutex. A real solution would be stronger ordering of disk_i_size updates against removing the ordered extent from the tree. Signed-off-by: -
Zheng Yan authored
This patch makes the back reference system to explicit record the location of parent node for all types of extents. The location of parent node is placed into the offset field of backref key. Every time a tree block is balanced, the back references for the affected lower level extents are updated. Signed-off-by: -
Chris Mason authored
Tree log blocks are only reserved, and should not ever get fully allocated on disk. This check makes sure they stay out of the extent tree. Signed-off-by: -
Chris Mason authored
Tree blocks were using async bio submission, but the sum was still being done directly during writepage. This moves the checksumming into the worker thread. Signed-off-by: -
Josef Bacik authored
1) replace the per fs_info extent_io_tree that tracked free space with two rb-trees per block group to track free space areas via offset and size. The reason to do this is because most allocations come with a hint byte where to start, so we can usually find a chunk of free space at that hint byte to satisfy the allocation and get good space packing. If we cannot find free space at or after the given offset we fall back on looking for a chunk of the given size as close to that given offset as possible. When we fall back on the size search we also try to find a slot as close to the size we want as possible, to avoid breaking small chunks off of huge areas if possible. 2) remove the extent_io_tree that tracked the block group cache from fs_info and replaced it with an rb-tree thats tracks block group cache via offset. also added a per space_info list that tracks the block group cache for the particular space so we can lookup related block groups easily. 3) cleaned up the allocation code to make it a little easier to read and a little less complicated. Basically there are 3 steps, first look from our provided hint. If we couldn't find from that given hint, start back at our original search start and look for space from there. If that fails try to allocate space if we can and start looking again. If not we're screwed and need to start over again. 4) small fixes. there were some issues in volumes.c where we wouldn't allocate the rest of the disk. fixed cow_file_range to actually pass the alloc_hint, which has helped a good bit in making the fs_mark test I run have semi-normal results as we run out of space. Generally with data allocations we don't track where we last allocated from, so everytime we did a data allocation we'd search through every block group that we have looking for free space. Now searching a block group with no free space isn't terribly time consuming, it was causing a slight degradation as we got more data block groups. The alloc_hint has fixed this slight degredation and made things semi-normal. There is still one nagging problem I'm working on where we will get ENOSPC when there is definitely plenty of space. This only happens with metadata allocations, and only when we are almost full. So you generally hit the 85% mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm still tracking it down, but until then this seems to be pretty stable and make a significant performance gain. Signed-off-by: -
Josef Bacik authored
cache block group had a few bugs in the error handling code, this makes sure paths get properly released and the correct return value goes out. Signed-off-by: -
Chris Mason authored
It was incorrectly adding an extra sizeof(struct btrfs_item) and causing false positives (oops) Signed-off-by: -
Chris Mason authored
I had incorrectly disabled the check for the block number being correct in the header block. Signed-off-by: -
Chris Mason authored
More testing has turned up a bug, disable this for now. Signed-off-by: -
Chris Mason authored
This is the same way the transaction code makes sure that all the other tree blocks are safely on disk. There's an extent_io tree for each root, and any blocks allocated to the tree logs are recorded in that tree. At tree-log sync, the extent_io tree is walked to flush down the dirty pages and wait for them. The main benefit is less time spent walking the tree log and skipping clean pages, and getting sequential IO down to the drive. Signed-off-by: -
Chris Mason authored
This changes the log tree copy code to use btrfs_insert_items and to work in larger batches where possible. Signed-off-by: -
Chris Mason authored
Since tree log blocks get freed every transaction, they never really need to be written to disk. This skips the step where we update metadata to record they were allocated. Signed-off-by: -
Chris Mason authored
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Chris Mason authored
Drop i_mutex during the commit Don't bother doing the fsync at all unless the dir is marked as dirtied and needing fsync in this transaction. For directories, this means that someone has unlinked a file from the dir without fsyncing the file. Signed-off-by:
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