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path: root/fs/btrfs/ref-cache.c
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* Btrfs: Fix checkpatch.pl warningsChris Mason2009-01-05
| | | | | | | 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>
* Btrfs: add and improve commentsChris Mason2008-09-29
| | | | | | | | | | | 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>
* Btrfs: drop WARN_ON from btrfs_add_leaf_refChris Mason2008-09-29
| | | | | | | | | | | | 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 <chris.mason@oracle.com>
* Btrfs: Add shared reference cacheZheng Yan2008-09-26
| | | | | | | | | | | | | 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: Chris Mason <chris.mason@oracle.com>
* Btrfs: implement memory reclaim for leaf reference cacheYan2008-09-25
| | | | | | | | | | | | | | The memory reclaiming issue happens when snapshot exists. In that case, some cache entries may not be used during old snapshot dropping, so they will remain in the cache until umount. The patch adds a field to struct btrfs_leaf_ref to record create time. Besides, the patch makes all dead roots of a given snapshot linked together in order of create time. After a old snapshot was completely dropped, we check the dead root list and remove all cache entries created before the oldest dead root in the list. Signed-off-by: Chris Mason <chris.mason@oracle.com>
* Btrfs: Leaf reference cache updateChris Mason2008-09-25
| | | | | | | | | | | | | | | This changes the reference cache to make a single cache per root instead of one cache per transaction, and to key by the byte number of the disk block instead of the keys inside. This makes it much less likely to have cache misses if a snapshot or something has an extra reference on a higher node or a leaf while the first transaction that added the leaf into the cache is dropping. Some throttling is added to functions that free blocks heavily so they wait for old transactions to drop. Signed-off-by: Chris Mason <chris.mason@oracle.com>
* Btrfs: Add a leaf reference cacheYan Zheng2008-09-25
Much of the IO done while dropping snapshots is done looking up leaves in the filesystem trees to see if they point to any extents and to drop the references on any extents found. This creates a cache so that IO isn't required. Signed-off-by: Chris Mason <chris.mason@oracle.com>