Fix two potential problems: 1. when largest extent needs to be invalidated, it will be reset in __drop_largest_extent, which makes __is_extent_same after always return false, and largest extent unchanged. Now we update it properly.
2. When extent is split and the latter part remains in tree, next_en should be the latter part instead of next extent of original extent. It will cause merge failure if there is in-place update, although there is not, I think this fix will still makes codes less ambiguous. This patch also simpfies codes of invalidating extents, and optimizes the procedues that split extent into two. Signed-off-by: Fan li <[email protected]> --- fs/f2fs/extent_cache.c | 150 +++++++++++++++++++----------------------------- 1 file changed, 58 insertions(+), 92 deletions(-) diff --git a/fs/f2fs/extent_cache.c b/fs/f2fs/extent_cache.c index 997ac86..b95cfb3 100644 --- a/fs/f2fs/extent_cache.c +++ b/fs/f2fs/extent_cache.c @@ -399,7 +399,7 @@ unsigned int f2fs_update_extent_tree_range(struct inode *inode, { struct f2fs_sb_info *sbi = F2FS_I_SB(inode); struct extent_tree *et = F2FS_I(inode)->extent_tree; - struct extent_node *en = NULL, *en1 = NULL, *en2 = NULL, *en3 = NULL; + struct extent_node *en = NULL, *en1 = NULL; struct extent_node *prev_en = NULL, *next_en = NULL; struct extent_info ei, dei, prev; struct rb_node **insert_p = NULL, *insert_parent = NULL; @@ -419,9 +419,6 @@ unsigned int f2fs_update_extent_tree_range(struct inode *inode, prev = et->largest; dei.len = 0; - /* we do not guarantee that the largest extent is cached all the time */ - __drop_largest_extent(inode, fofs); - /* 1. lookup first extent node in range [fofs, fofs + len - 1] */ en = __lookup_extent_tree_ret(et, fofs, &prev_en, &next_en, &insert_p, &insert_parent); @@ -441,114 +438,83 @@ unsigned int f2fs_update_extent_tree_range(struct inode *inode, /* 2. invlidate all extent nodes in range [fofs, fofs + len - 1] */ while (en) { - struct rb_node *node; + struct rb_node *node = NULL; + int parts = 0; /* # of parts current extent split into */ + unsigned int org_end; if (pos >= end) break; dei = en->ei; - en1 = en2 = NULL; + next_en = en1 = NULL; - node = rb_next(&en->rb_node); + f2fs_bug_on(sbi, pos < dei.fofs || pos >= dei.fofs + dei.len); - /* - * 2.1 there are four cases when we invalidate blkaddr in extent - * node, |V: valid address, X: will be invalidated| - */ - /* case#1, invalidate right part of extent node |VVVVVXXXXX| */ - if (pos > dei.fofs && end >= dei.fofs + dei.len) { + __drop_largest_extent(inode, pos); + + if (pos > dei.fofs && pos - dei.fofs >= F2FS_MIN_EXTENT_LEN) { en->ei.len = pos - dei.fofs; + parts = 1; + } - if (en->ei.len < F2FS_MIN_EXTENT_LEN) { - __detach_extent_node(sbi, et, en); - insert_p = NULL; - insert_parent = NULL; - goto update; + org_end = dei.fofs + dei.len; + if (end < org_end && + org_end - end >= F2FS_MIN_EXTENT_LEN) { + if (parts) { + set_extent_info(&ei, end, + end - dei.fofs + dei.blk, + org_end - end); + en1 = __insert_extent_tree(sbi, et, &ei, + NULL, NULL); + next_en = en1; + } else { + en->ei.fofs = end; + en->ei.blk += end - dei.fofs; + en->ei.len -= end - dei.fofs; + next_en = en; } - - if (__is_extent_same(&dei, &et->largest)) - et->largest = en->ei; - goto next; + parts++; } - /* case#2, invalidate left part of extent node |XXXXXVVVVV| */ - if (pos <= dei.fofs && end < dei.fofs + dei.len) { - en->ei.fofs = end; - en->ei.blk += end - dei.fofs; - en->ei.len -= end - dei.fofs; - - if (en->ei.len < F2FS_MIN_EXTENT_LEN) { - __detach_extent_node(sbi, et, en); - insert_p = NULL; - insert_parent = NULL; - goto update; - } + if (!next_en) { + node = rb_next(&en->rb_node); + next_en = node ? + rb_entry(node, struct extent_node, rb_node) + : NULL; + } - if (__is_extent_same(&dei, &et->largest)) + if (parts) { + if (en->ei.len > et->largest.len) et->largest = en->ei; - goto next; + } else { + __detach_extent_node(sbi, et, en); } - __detach_extent_node(sbi, et, en); - /* - * if we remove node in rb-tree, our parent node pointer may - * point the wrong place, discard them. + * if original extent is split into zero or two parts, extent + * tree has been altered by deletion or insertion, therefore + * invalidate pointers regard to tree. */ - insert_p = NULL; - insert_parent = NULL; - - /* case#3, invalidate entire extent node |XXXXXXXXXX| */ - if (pos <= dei.fofs && end >= dei.fofs + dei.len) { - if (__is_extent_same(&dei, &et->largest)) - et->largest.len = 0; - goto update; + if (parts != 1) { + insert_p = NULL; + insert_parent = NULL; } - /* - * case#4, invalidate data in the middle of extent node - * |VVVXXXXVVV| - */ - if (dei.len > F2FS_MIN_EXTENT_LEN) { - unsigned int endofs; - - /* insert left part of split extent into cache */ - if (pos - dei.fofs >= F2FS_MIN_EXTENT_LEN) { - set_extent_info(&ei, dei.fofs, dei.blk, - pos - dei.fofs); - en1 = __insert_extent_tree(sbi, et, &ei, - NULL, NULL); - } - - /* insert right part of split extent into cache */ - endofs = dei.fofs + dei.len; - if (endofs - end >= F2FS_MIN_EXTENT_LEN) { - set_extent_info(&ei, end, - end - dei.fofs + dei.blk, - endofs - end); - en2 = __insert_extent_tree(sbi, et, &ei, - NULL, NULL); - } - } -update: - /* 2.2 update in global extent list */ + /* update in global extent list */ spin_lock(&sbi->extent_lock); - if (en && !list_empty(&en->list)) + if (!parts && !list_empty(&en->list)) list_del(&en->list); if (en1) list_add_tail(&en1->list, &sbi->extent_list); - if (en2) - list_add_tail(&en2->list, &sbi->extent_list); spin_unlock(&sbi->extent_lock); - /* 2.3 release extent node */ - if (en) + /* release extent node */ + if (!parts) kmem_cache_free(extent_node_slab, en); -next: - en = node ? rb_entry(node, struct extent_node, rb_node) : NULL; - next_en = en; - if (en) - pos = en->ei.fofs; + + en = next_en; + if (next_en) + pos = next_en->ei.fofs; } update_extent: @@ -557,10 +523,10 @@ update_extent: struct extent_node *den = NULL; set_extent_info(&ei, fofs, blkaddr, len); - en3 = __try_merge_extent_node(sbi, et, &ei, &den, + en1 = __try_merge_extent_node(sbi, et, &ei, &den, prev_en, next_en); - if (!en3) - en3 = __insert_extent_tree(sbi, et, &ei, + if (!en1) + en1 = __insert_extent_tree(sbi, et, &ei, insert_p, insert_parent); /* give up extent_cache, if split and small updates happen */ @@ -572,11 +538,11 @@ update_extent: } spin_lock(&sbi->extent_lock); - if (en3) { - if (list_empty(&en3->list)) - list_add_tail(&en3->list, &sbi->extent_list); + if (en1) { + if (list_empty(&en1->list)) + list_add_tail(&en1->list, &sbi->extent_list); else - list_move_tail(&en3->list, &sbi->extent_list); + list_move_tail(&en1->list, &sbi->extent_list); } if (den && !list_empty(&den->list)) list_del(&den->list); -- 1.7.9.5 ------------------------------------------------------------------------------ Monitor Your Dynamic Infrastructure at Any Scale With Datadog! 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