forked from Minki/linux
fcebe4562d
Currently qgroups account for space by intercepting delayed ref updates to fs trees. It does this by adding sequence numbers to delayed ref updates so that it can figure out how the tree looked before the update so we can adjust the counters properly. The problem with this is that it does not allow delayed refs to be merged, so if you say are defragging an extent with 5k snapshots pointing to it we will thrash the delayed ref lock because we need to go back and manually merge these things together. Instead we want to process quota changes when we know they are going to happen, like when we first allocate an extent, we free a reference for an extent, we add new references etc. This patch accomplishes this by only adding qgroup operations for real ref changes. We only modify the sequence number when we need to lookup roots for bytenrs, this reduces the amount of churn on the sequence number and allows us to merge delayed refs as we add them most of the time. This patch encompasses a bunch of architectural changes 1) qgroup ref operations: instead of tracking qgroup operations through the delayed refs we simply add new ref operations whenever we notice that we need to when we've modified the refs themselves. 2) tree mod seq: we no longer have this separation of major/minor counters. this makes the sequence number stuff much more sane and we can remove some locking that was needed to protect the counter. 3) delayed ref seq: we now read the tree mod seq number and use that as our sequence. This means each new delayed ref doesn't have it's own unique sequence number, rather whenever we go to lookup backrefs we inc the sequence number so we can make sure to keep any new operations from screwing up our world view at that given point. This allows us to merge delayed refs during runtime. With all of these changes the delayed ref stuff is a little saner and the qgroup accounting stuff no longer goes negative in some cases like it was before. Thanks, Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
78 lines
2.6 KiB
C
78 lines
2.6 KiB
C
/*
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* Copyright (C) 2011 STRATO. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License v2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 021110-1307, USA.
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*/
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#ifndef __BTRFS_BACKREF__
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#define __BTRFS_BACKREF__
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#include <linux/btrfs.h>
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#include "ulist.h"
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#include "extent_io.h"
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struct inode_fs_paths {
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struct btrfs_path *btrfs_path;
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struct btrfs_root *fs_root;
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struct btrfs_data_container *fspath;
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};
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typedef int (iterate_extent_inodes_t)(u64 inum, u64 offset, u64 root,
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void *ctx);
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int inode_item_info(u64 inum, u64 ioff, struct btrfs_root *fs_root,
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struct btrfs_path *path);
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int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical,
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struct btrfs_path *path, struct btrfs_key *found_key,
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u64 *flags);
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int tree_backref_for_extent(unsigned long *ptr, struct extent_buffer *eb,
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struct btrfs_extent_item *ei, u32 item_size,
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u64 *out_root, u8 *out_level);
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int iterate_extent_inodes(struct btrfs_fs_info *fs_info,
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u64 extent_item_objectid,
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u64 extent_offset, int search_commit_root,
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iterate_extent_inodes_t *iterate, void *ctx);
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int iterate_inodes_from_logical(u64 logical, struct btrfs_fs_info *fs_info,
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struct btrfs_path *path,
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iterate_extent_inodes_t *iterate, void *ctx);
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int paths_from_inode(u64 inum, struct inode_fs_paths *ipath);
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int btrfs_find_all_roots(struct btrfs_trans_handle *trans,
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struct btrfs_fs_info *fs_info, u64 bytenr,
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u64 time_seq, struct ulist **roots);
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char *btrfs_ref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path,
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u32 name_len, unsigned long name_off,
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struct extent_buffer *eb_in, u64 parent,
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char *dest, u32 size);
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struct btrfs_data_container *init_data_container(u32 total_bytes);
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struct inode_fs_paths *init_ipath(s32 total_bytes, struct btrfs_root *fs_root,
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struct btrfs_path *path);
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void free_ipath(struct inode_fs_paths *ipath);
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int btrfs_find_one_extref(struct btrfs_root *root, u64 inode_objectid,
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u64 start_off, struct btrfs_path *path,
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struct btrfs_inode_extref **ret_extref,
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u64 *found_off);
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int __init btrfs_prelim_ref_init(void);
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void btrfs_prelim_ref_exit(void);
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#endif
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