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由 Qu Wenruo 提交于
Unlike reservation calculation used in inode rsv for metadata, qgroup doesn't really need to care about things like csum size or extent usage for the whole tree COW. Qgroups care more about net change of the extent usage. That's to say, if we're going to insert one file extent, it will mostly find its place in COWed tree block, leaving no change in extent usage. Or causing a leaf split, resulting in one new net extent and increasing qgroup number by nodesize. Or in an even more rare case, increase the tree level, increasing qgroup number by 2 * nodesize. So here instead of using the complicated calculation for extent allocator, which cares more about accuracy and no error, qgroup doesn't need that over-estimated reservation. This patch will maintain 2 new members in btrfs_block_rsv structure for qgroup, using much smaller calculation for qgroup rsv, reducing false EDQUOT. Signed-off-by: NDavid Sterba <dsterba@suse.com> Signed-off-by: NQu Wenruo <wqu@suse.com>
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