From 54c2258cd63a81283cf88b2bd9457c61ee2cd66f Mon Sep 17 00:00:00 2001 From: Chao Yu Date: Tue, 11 Apr 2017 09:25:22 +0800 Subject: [PATCH] f2fs: extract rb-tree operation infrastructure rb-tree lookup/update functions are deeply coupled into extent cache codes, it's very hard to reuse these basic functions, this patch extracts common rb-tree operation infrastructure for latter reusing. Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim --- fs/f2fs/extent_cache.c | 291 +++++++++++++++++++++++------------------ fs/f2fs/f2fs.h | 20 ++- 2 files changed, 179 insertions(+), 132 deletions(-) diff --git a/fs/f2fs/extent_cache.c b/fs/f2fs/extent_cache.c index c6934f014e0f..68e649a31c7d 100644 --- a/fs/f2fs/extent_cache.c +++ b/fs/f2fs/extent_cache.c @@ -18,6 +18,146 @@ #include "node.h" #include +static struct rb_entry *__lookup_rb_tree_fast(struct rb_entry *cached_re, + unsigned int ofs) +{ + if (cached_re) { + if (cached_re->ofs <= ofs && + cached_re->ofs + cached_re->len > ofs) { + return cached_re; + } + } + return NULL; +} + +static struct rb_entry *__lookup_rb_tree_slow(struct rb_root *root, + unsigned int ofs) +{ + struct rb_node *node = root->rb_node; + struct rb_entry *re; + + while (node) { + re = rb_entry(node, struct rb_entry, rb_node); + + if (ofs < re->ofs) + node = node->rb_left; + else if (ofs >= re->ofs + re->len) + node = node->rb_right; + else + return re; + } + return NULL; +} + +static struct rb_entry *__lookup_rb_tree(struct rb_root *root, + struct rb_entry *cached_re, unsigned int ofs) +{ + struct rb_entry *re; + + re = __lookup_rb_tree_fast(cached_re, ofs); + if (!re) + return __lookup_rb_tree_slow(root, ofs); + + return re; +} + +static struct rb_node **__lookup_rb_tree_for_insert(struct f2fs_sb_info *sbi, + struct rb_root *root, struct rb_node **parent, + unsigned int ofs) +{ + struct rb_node **p = &root->rb_node; + struct rb_entry *re; + + while (*p) { + *parent = *p; + re = rb_entry(*parent, struct rb_entry, rb_node); + + if (ofs < re->ofs) + p = &(*p)->rb_left; + else if (ofs >= re->ofs + re->len) + p = &(*p)->rb_right; + else + f2fs_bug_on(sbi, 1); + } + + return p; +} + +/* + * lookup rb entry in position of @ofs in rb-tree, + * if hit, return the entry, otherwise, return NULL + * @prev_ex: extent before ofs + * @next_ex: extent after ofs + * @insert_p: insert point for new extent at ofs + * in order to simpfy the insertion after. + * tree must stay unchanged between lookup and insertion. + */ +static struct rb_entry *__lookup_rb_tree_ret(struct rb_root *root, + struct rb_entry *cached_re, + unsigned int ofs, + struct rb_entry **prev_entry, + struct rb_entry **next_entry, + struct rb_node ***insert_p, + struct rb_node **insert_parent) +{ + struct rb_node **pnode = &root->rb_node; + struct rb_node *parent = NULL, *tmp_node; + struct rb_entry *re = cached_re; + + *insert_p = NULL; + *insert_parent = NULL; + *prev_entry = NULL; + *next_entry = NULL; + + if (RB_EMPTY_ROOT(root)) + return NULL; + + if (re) { + if (re->ofs <= ofs && re->ofs + re->len > ofs) + goto lookup_neighbors; + } + + while (*pnode) { + parent = *pnode; + re = rb_entry(*pnode, struct rb_entry, rb_node); + + if (ofs < re->ofs) + pnode = &(*pnode)->rb_left; + else if (ofs >= re->ofs + re->len) + pnode = &(*pnode)->rb_right; + else + goto lookup_neighbors; + } + + *insert_p = pnode; + *insert_parent = parent; + + re = rb_entry(parent, struct rb_entry, rb_node); + tmp_node = parent; + if (parent && ofs > re->ofs) + tmp_node = rb_next(parent); + *next_entry = rb_entry_safe(tmp_node, struct rb_entry, rb_node); + + tmp_node = parent; + if (parent && ofs < re->ofs) + tmp_node = rb_prev(parent); + *prev_entry = rb_entry_safe(tmp_node, struct rb_entry, rb_node); + return NULL; + +lookup_neighbors: + if (ofs == re->ofs) { + /* lookup prev node for merging backward later */ + tmp_node = rb_prev(&re->rb_node); + *prev_entry = rb_entry_safe(tmp_node, struct rb_entry, rb_node); + } + if (ofs == re->ofs + re->len - 1) { + /* lookup next node for merging frontward later */ + tmp_node = rb_next(&re->rb_node); + *next_entry = rb_entry_safe(tmp_node, struct rb_entry, rb_node); + } + return re; +} + static struct kmem_cache *extent_tree_slab; static struct kmem_cache *extent_node_slab; @@ -102,36 +242,6 @@ static struct extent_tree *__grab_extent_tree(struct inode *inode) return et; } -static struct extent_node *__lookup_extent_tree(struct f2fs_sb_info *sbi, - struct extent_tree *et, unsigned int fofs) -{ - struct rb_node *node = et->root.rb_node; - struct extent_node *en = et->cached_en; - - if (en) { - struct extent_info *cei = &en->ei; - - if (cei->fofs <= fofs && cei->fofs + cei->len > fofs) { - stat_inc_cached_node_hit(sbi); - return en; - } - } - - while (node) { - en = rb_entry(node, struct extent_node, rb_node); - - if (fofs < en->ei.fofs) { - node = node->rb_left; - } else if (fofs >= en->ei.fofs + en->ei.len) { - node = node->rb_right; - } else { - stat_inc_rbtree_node_hit(sbi); - return en; - } - } - return NULL; -} - static struct extent_node *__init_extent_tree(struct f2fs_sb_info *sbi, struct extent_tree *et, struct extent_info *ei) { @@ -237,17 +347,24 @@ static bool f2fs_lookup_extent_tree(struct inode *inode, pgoff_t pgofs, goto out; } - en = __lookup_extent_tree(sbi, et, pgofs); - if (en) { - *ei = en->ei; - spin_lock(&sbi->extent_lock); - if (!list_empty(&en->list)) { - list_move_tail(&en->list, &sbi->extent_list); - et->cached_en = en; - } - spin_unlock(&sbi->extent_lock); - ret = true; + en = (struct extent_node *)__lookup_rb_tree(&et->root, + (struct rb_entry *)et->cached_en, pgofs); + if (!en) + goto out; + + if (en == et->cached_en) + stat_inc_cached_node_hit(sbi); + else + stat_inc_rbtree_node_hit(sbi); + + *ei = en->ei; + spin_lock(&sbi->extent_lock); + if (!list_empty(&en->list)) { + list_move_tail(&en->list, &sbi->extent_list); + et->cached_en = en; } + spin_unlock(&sbi->extent_lock); + ret = true; out: stat_inc_total_hit(sbi); read_unlock(&et->lock); @@ -256,83 +373,6 @@ out: return ret; } - -/* - * lookup extent at @fofs, if hit, return the extent - * if not, return NULL and - * @prev_ex: extent before fofs - * @next_ex: extent after fofs - * @insert_p: insert point for new extent at fofs - * in order to simpfy the insertion after. - * tree must stay unchanged between lookup and insertion. - */ -static struct extent_node *__lookup_extent_tree_ret(struct extent_tree *et, - unsigned int fofs, - struct extent_node **prev_ex, - struct extent_node **next_ex, - struct rb_node ***insert_p, - struct rb_node **insert_parent) -{ - struct rb_node **pnode = &et->root.rb_node; - struct rb_node *parent = NULL, *tmp_node; - struct extent_node *en = et->cached_en; - - *insert_p = NULL; - *insert_parent = NULL; - *prev_ex = NULL; - *next_ex = NULL; - - if (RB_EMPTY_ROOT(&et->root)) - return NULL; - - if (en) { - struct extent_info *cei = &en->ei; - - if (cei->fofs <= fofs && cei->fofs + cei->len > fofs) - goto lookup_neighbors; - } - - while (*pnode) { - parent = *pnode; - en = rb_entry(*pnode, struct extent_node, rb_node); - - if (fofs < en->ei.fofs) - pnode = &(*pnode)->rb_left; - else if (fofs >= en->ei.fofs + en->ei.len) - pnode = &(*pnode)->rb_right; - else - goto lookup_neighbors; - } - - *insert_p = pnode; - *insert_parent = parent; - - en = rb_entry(parent, struct extent_node, rb_node); - tmp_node = parent; - if (parent && fofs > en->ei.fofs) - tmp_node = rb_next(parent); - *next_ex = rb_entry_safe(tmp_node, struct extent_node, rb_node); - - tmp_node = parent; - if (parent && fofs < en->ei.fofs) - tmp_node = rb_prev(parent); - *prev_ex = rb_entry_safe(tmp_node, struct extent_node, rb_node); - return NULL; - -lookup_neighbors: - if (fofs == en->ei.fofs) { - /* lookup prev node for merging backward later */ - tmp_node = rb_prev(&en->rb_node); - *prev_ex = rb_entry_safe(tmp_node, struct extent_node, rb_node); - } - if (fofs == en->ei.fofs + en->ei.len - 1) { - /* lookup next node for merging frontward later */ - tmp_node = rb_next(&en->rb_node); - *next_ex = rb_entry_safe(tmp_node, struct extent_node, rb_node); - } - return en; -} - static struct extent_node *__try_merge_extent_node(struct inode *inode, struct extent_tree *et, struct extent_info *ei, struct extent_node *prev_ex, @@ -387,17 +427,7 @@ static struct extent_node *__insert_extent_tree(struct inode *inode, goto do_insert; } - while (*p) { - parent = *p; - en = rb_entry(parent, struct extent_node, rb_node); - - if (ei->fofs < en->ei.fofs) - p = &(*p)->rb_left; - else if (ei->fofs >= en->ei.fofs + en->ei.len) - p = &(*p)->rb_right; - else - f2fs_bug_on(sbi, 1); - } + p = __lookup_rb_tree_for_insert(sbi, &et->root, &parent, ei->fofs); do_insert: en = __attach_extent_node(sbi, et, ei, parent, p); if (!en) @@ -447,7 +477,10 @@ static void f2fs_update_extent_tree_range(struct inode *inode, __drop_largest_extent(inode, fofs, len); /* 1. lookup first extent node in range [fofs, fofs + len - 1] */ - en = __lookup_extent_tree_ret(et, fofs, &prev_en, &next_en, + en = (struct extent_node *)__lookup_rb_tree_ret(&et->root, + (struct rb_entry *)et->cached_en, fofs, + (struct rb_entry **)&prev_en, + (struct rb_entry **)&next_en, &insert_p, &insert_parent); if (!en) en = next_en; diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index 4615c96f8e39..562db8989a4e 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -377,16 +377,30 @@ enum { /* number of extent info in extent cache we try to shrink */ #define EXTENT_CACHE_SHRINK_NUMBER 128 +struct rb_entry { + struct rb_node rb_node; /* rb node located in rb-tree */ + unsigned int ofs; /* start offset of the entry */ + unsigned int len; /* length of the entry */ +}; + struct extent_info { unsigned int fofs; /* start offset in a file */ - u32 blk; /* start block address of the extent */ unsigned int len; /* length of the extent */ + u32 blk; /* start block address of the extent */ }; struct extent_node { - struct rb_node rb_node; /* rb node located in rb-tree */ + struct rb_node rb_node; + union { + struct { + unsigned int fofs; + unsigned int len; + u32 blk; + }; + struct extent_info ei; /* extent info */ + + }; struct list_head list; /* node in global extent list of sbi */ - struct extent_info ei; /* extent info */ struct extent_tree *et; /* extent tree pointer */ }; -- 2.20.1