diff options
Diffstat (limited to 'fs/ext4/extents_status.c')
| -rw-r--r-- | fs/ext4/extents_status.c | 631 |
1 files changed, 467 insertions, 164 deletions
diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c index 564d981a2fc..f768f4a98a2 100644 --- a/fs/ext4/extents_status.c +++ b/fs/ext4/extents_status.c @@ -23,40 +23,53 @@ * (e.g. Reservation space warning), and provide extent-level locking. * Delay extent tree is the first step to achieve this goal. It is * original built by Yongqiang Yang. At that time it is called delay - * extent tree, whose goal is only track delay extent in memory to + * extent tree, whose goal is only track delayed extents in memory to * simplify the implementation of fiemap and bigalloc, and introduce * lseek SEEK_DATA/SEEK_HOLE support. That is why it is still called - * delay extent tree at the following comment. But for better - * understand what it does, it has been rename to extent status tree. + * delay extent tree at the first commit. But for better understand + * what it does, it has been rename to extent status tree. * - * Currently the first step has been done. All delay extents are - * tracked in the tree. It maintains the delay extent when a delay - * allocation is issued, and the delay extent is written out or + * Step1: + * Currently the first step has been done. All delayed extents are + * tracked in the tree. It maintains the delayed extent when a delayed + * allocation is issued, and the delayed extent is written out or * invalidated. Therefore the implementation of fiemap and bigalloc * are simplified, and SEEK_DATA/SEEK_HOLE are introduced. * * The following comment describes the implemenmtation of extent * status tree and future works. + * + * Step2: + * In this step all extent status are tracked by extent status tree. + * Thus, we can first try to lookup a block mapping in this tree before + * finding it in extent tree. Hence, single extent cache can be removed + * because extent status tree can do a better job. Extents in status + * tree are loaded on-demand. Therefore, the extent status tree may not + * contain all of the extents in a file. Meanwhile we define a shrinker + * to reclaim memory from extent status tree because fragmented extent + * tree will make status tree cost too much memory. written/unwritten/- + * hole extents in the tree will be reclaimed by this shrinker when we + * are under high memory pressure. Delayed extents will not be + * reclimed because fiemap, bigalloc, and seek_data/hole need it. */ /* - * extents status tree implementation for ext4. + * Extent status tree implementation for ext4. * * * ========================================================================== - * Extents status encompass delayed extents and extent locks + * Extent status tree tracks all extent status. * - * 1. Why delayed extent implementation ? + * 1. Why we need to implement extent status tree? * - * Without delayed extent, ext4 identifies a delayed extent by looking + * Without extent status tree, ext4 identifies a delayed extent by looking * up page cache, this has several deficiencies - complicated, buggy, * and inefficient code. * - * FIEMAP, SEEK_HOLE/DATA, bigalloc, punch hole and writeout all need - * to know if a block or a range of blocks are belonged to a delayed - * extent. + * FIEMAP, SEEK_HOLE/DATA, bigalloc, and writeout all need to know if a + * block or a range of blocks are belonged to a delayed extent. * - * Let us have a look at how they do without delayed extents implementation. + * Let us have a look at how they do without extent status tree. * -- FIEMAP * FIEMAP looks up page cache to identify delayed allocations from holes. * @@ -68,47 +81,48 @@ * already under delayed allocation or not to determine whether * quota reserving is needed for the cluster. * - * -- punch hole - * punch hole looks up page cache to identify a delayed extent. - * * -- writeout * Writeout looks up whole page cache to see if a buffer is * mapped, If there are not very many delayed buffers, then it is * time comsuming. * - * With delayed extents implementation, FIEMAP, SEEK_HOLE/DATA, + * With extent status tree implementation, FIEMAP, SEEK_HOLE/DATA, * bigalloc and writeout can figure out if a block or a range of * blocks is under delayed allocation(belonged to a delayed extent) or - * not by searching the delayed extent tree. + * not by searching the extent tree. * * * ========================================================================== - * 2. ext4 delayed extents impelmentation + * 2. Ext4 extent status tree impelmentation + * + * -- extent + * A extent is a range of blocks which are contiguous logically and + * physically. Unlike extent in extent tree, this extent in ext4 is + * a in-memory struct, there is no corresponding on-disk data. There + * is no limit on length of extent, so an extent can contain as many + * blocks as they are contiguous logically and physically. * - * -- delayed extent - * A delayed extent is a range of blocks which are contiguous - * logically and under delayed allocation. Unlike extent in - * ext4, delayed extent in ext4 is a in-memory struct, there is - * no corresponding on-disk data. There is no limit on length of - * delayed extent, so a delayed extent can contain as many blocks - * as they are contiguous logically. + * -- extent status tree + * Every inode has an extent status tree and all allocation blocks + * are added to the tree with different status. The extent in the + * tree are ordered by logical block no. * - * -- delayed extent tree - * Every inode has a delayed extent tree and all under delayed - * allocation blocks are added to the tree as delayed extents. - * Delayed extents in the tree are ordered by logical block no. + * -- operations on a extent status tree + * There are three important operations on a delayed extent tree: find + * next extent, adding a extent(a range of blocks) and removing a extent. * - * -- operations on a delayed extent tree - * There are three operations on a delayed extent tree: find next - * delayed extent, adding a space(a range of blocks) and removing - * a space. + * -- race on a extent status tree + * Extent status tree is protected by inode->i_es_lock. * - * -- race on a delayed extent tree - * Delayed extent tree is protected inode->i_es_lock. + * -- memory consumption + * Fragmented extent tree will make extent status tree cost too much + * memory. Hence, we will reclaim written/unwritten/hole extents from + * the tree under a heavy memory pressure. * * * ========================================================================== - * 3. performance analysis + * 3. Performance analysis + * * -- overhead * 1. There is a cache extent for write access, so if writes are * not very random, adding space operaions are in O(1) time. @@ -120,15 +134,21 @@ * * ========================================================================== * 4. TODO list - * -- Track all extent status * - * -- Improve get block process + * -- Refactor delayed space reservation * * -- Extent-level locking */ static struct kmem_cache *ext4_es_cachep; +static int __es_insert_extent(struct inode *inode, struct extent_status *newes); +static int __es_remove_extent(struct inode *inode, ext4_lblk_t lblk, + ext4_lblk_t end); +static int __es_try_to_reclaim_extents(struct ext4_inode_info *ei, + int nr_to_scan); +static int ext4_es_reclaim_extents_count(struct super_block *sb); + int __init ext4_init_es(void) { ext4_es_cachep = KMEM_CACHE(extent_status, SLAB_RECLAIM_ACCOUNT); @@ -161,7 +181,9 @@ static void ext4_es_print_tree(struct inode *inode) while (node) { struct extent_status *es; es = rb_entry(node, struct extent_status, rb_node); - printk(KERN_DEBUG " [%u/%u)", es->start, es->len); + printk(KERN_DEBUG " [%u/%u) %llu %llx", + es->es_lblk, es->es_len, + ext4_es_pblock(es), ext4_es_status(es)); node = rb_next(node); } printk(KERN_DEBUG "\n"); @@ -170,10 +192,10 @@ static void ext4_es_print_tree(struct inode *inode) #define ext4_es_print_tree(inode) #endif -static inline ext4_lblk_t extent_status_end(struct extent_status *es) +static inline ext4_lblk_t ext4_es_end(struct extent_status *es) { - BUG_ON(es->start + es->len < es->start); - return es->start + es->len - 1; + BUG_ON(es->es_lblk + es->es_len < es->es_lblk); + return es->es_lblk + es->es_len - 1; } /* @@ -181,25 +203,25 @@ static inline ext4_lblk_t extent_status_end(struct extent_status *es) * it can't be found, try to find next extent. */ static struct extent_status *__es_tree_search(struct rb_root *root, - ext4_lblk_t offset) + ext4_lblk_t lblk) { struct rb_node *node = root->rb_node; struct extent_status *es = NULL; while (node) { es = rb_entry(node, struct extent_status, rb_node); - if (offset < es->start) + if (lblk < es->es_lblk) node = node->rb_left; - else if (offset > extent_status_end(es)) + else if (lblk > ext4_es_end(es)) node = node->rb_right; else return es; } - if (es && offset < es->start) + if (es && lblk < es->es_lblk) return es; - if (es && offset > extent_status_end(es)) { + if (es && lblk > ext4_es_end(es)) { node = rb_next(&es->rb_node); return node ? rb_entry(node, struct extent_status, rb_node) : NULL; @@ -209,79 +231,121 @@ static struct extent_status *__es_tree_search(struct rb_root *root, } /* - * ext4_es_find_extent: find the 1st delayed extent covering @es->start - * if it exists, otherwise, the next extent after @es->start. + * ext4_es_find_delayed_extent: find the 1st delayed extent covering @es->lblk + * if it exists, otherwise, the next extent after @es->lblk. * * @inode: the inode which owns delayed extents + * @lblk: the offset where we start to search * @es: delayed extent that we found - * - * Returns the first block of the next extent after es, otherwise - * EXT_MAX_BLOCKS if no delay extent is found. - * Delayed extent is returned via @es. */ -ext4_lblk_t ext4_es_find_extent(struct inode *inode, struct extent_status *es) +void ext4_es_find_delayed_extent(struct inode *inode, ext4_lblk_t lblk, + struct extent_status *es) { struct ext4_es_tree *tree = NULL; struct extent_status *es1 = NULL; struct rb_node *node; - ext4_lblk_t ret = EXT_MAX_BLOCKS; - trace_ext4_es_find_extent_enter(inode, es->start); + BUG_ON(es == NULL); + trace_ext4_es_find_delayed_extent_enter(inode, lblk); read_lock(&EXT4_I(inode)->i_es_lock); tree = &EXT4_I(inode)->i_es_tree; - /* find delay extent in cache firstly */ + /* find extent in cache firstly */ + es->es_lblk = es->es_len = es->es_pblk = 0; if (tree->cache_es) { es1 = tree->cache_es; - if (in_range(es->start, es1->start, es1->len)) { - es_debug("%u cached by [%u/%u)\n", - es->start, es1->start, es1->len); + if (in_range(lblk, es1->es_lblk, es1->es_len)) { + es_debug("%u cached by [%u/%u) %llu %llx\n", + lblk, es1->es_lblk, es1->es_len, + ext4_es_pblock(es1), ext4_es_status(es1)); goto out; } } - es->len = 0; - es1 = __es_tree_search(&tree->root, es->start); + es1 = __es_tree_search(&tree->root, lblk); out: - if (es1) { - tree->cache_es = es1; - es->start = es1->start; - es->len = es1->len; - node = rb_next(&es1->rb_node); - if (node) { + if (es1 && !ext4_es_is_delayed(es1)) { + while ((node = rb_next(&es1->rb_node)) != NULL) { es1 = rb_entry(node, struct extent_status, rb_node); - ret = es1->start; + if (ext4_es_is_delayed(es1)) + break; } } + if (es1 && ext4_es_is_delayed(es1)) { + tree->cache_es = es1; + es->es_lblk = es1->es_lblk; + es->es_len = es1->es_len; + es->es_pblk = es1->es_pblk; + } + read_unlock(&EXT4_I(inode)->i_es_lock); - trace_ext4_es_find_extent_exit(inode, es, ret); - return ret; + ext4_es_lru_add(inode); + trace_ext4_es_find_delayed_extent_exit(inode, es); } static struct extent_status * -ext4_es_alloc_extent(ext4_lblk_t start, ext4_lblk_t len) +ext4_es_alloc_extent(struct inode *inode, ext4_lblk_t lblk, ext4_lblk_t len, + ext4_fsblk_t pblk) { struct extent_status *es; es = kmem_cache_alloc(ext4_es_cachep, GFP_ATOMIC); if (es == NULL) return NULL; - es->start = start; - es->len = len; + es->es_lblk = lblk; + es->es_len = len; + es->es_pblk = pblk; + + /* + * We don't count delayed extent because we never try to reclaim them + */ + if (!ext4_es_is_delayed(es)) + EXT4_I(inode)->i_es_lru_nr++; + return es; } -static void ext4_es_free_extent(struct extent_status *es) +static void ext4_es_free_extent(struct inode *inode, struct extent_status *es) { + /* Decrease the lru counter when this es is not delayed */ + if (!ext4_es_is_delayed(es)) { + BUG_ON(EXT4_I(inode)->i_es_lru_nr == 0); + EXT4_I(inode)->i_es_lru_nr--; + } + kmem_cache_free(ext4_es_cachep, es); } +/* + * Check whether or not two extents can be merged + * Condition: + * - logical block number is contiguous + * - physical block number is contiguous + * - status is equal + */ +static int ext4_es_can_be_merged(struct extent_status *es1, + struct extent_status *es2) +{ + if (es1->es_lblk + es1->es_len != es2->es_lblk) + return 0; + + if (ext4_es_status(es1) != ext4_es_status(es2)) + return 0; + + if ((ext4_es_is_written(es1) || ext4_es_is_unwritten(es1)) && + (ext4_es_pblock(es1) + es1->es_len != ext4_es_pblock(es2))) + return 0; + + return 1; +} + static struct extent_status * -ext4_es_try_to_merge_left(struct ext4_es_tree *tree, struct extent_status *es) +ext4_es_try_to_merge_left(struct inode *inode, struct extent_status *es) { + struct ext4_es_tree *tree = &EXT4_I(inode)->i_es_tree; struct extent_status *es1; struct rb_node *node; @@ -290,10 +354,10 @@ ext4_es_try_to_merge_left(struct ext4_es_tree *tree, struct extent_status *es) return es; es1 = rb_entry(node, struct extent_status, rb_node); - if (es->start == extent_status_end(es1) + 1) { - es1->len += es->len; + if (ext4_es_can_be_merged(es1, es)) { + es1->es_len += es->es_len; rb_erase(&es->rb_node, &tree->root); - ext4_es_free_extent(es); + ext4_es_free_extent(inode, es); es = es1; } @@ -301,8 +365,9 @@ ext4_es_try_to_merge_left(struct ext4_es_tree *tree, struct extent_status *es) } static struct extent_status * -ext4_es_try_to_merge_right(struct ext4_es_tree *tree, struct extent_status *es) +ext4_es_try_to_merge_right(struct inode *inode, struct extent_status *es) { + struct ext4_es_tree *tree = &EXT4_I(inode)->i_es_tree; struct extent_status *es1; struct rb_node *node; @@ -311,69 +376,57 @@ ext4_es_try_to_merge_right(struct ext4_es_tree *tree, struct extent_status *es) return es; es1 = rb_entry(node, struct extent_status, rb_node); - if (es1->start == extent_status_end(es) + 1) { - es->len += es1->len; + if (ext4_es_can_be_merged(es, es1)) { + es->es_len += es1->es_len; rb_erase(node, &tree->root); - ext4_es_free_extent(es1); + ext4_es_free_extent(inode, es1); } return es; } -static int __es_insert_extent(struct ext4_es_tree *tree, ext4_lblk_t offset, - ext4_lblk_t len) +static int __es_insert_extent(struct inode *inode, struct extent_status *newes) { + struct ext4_es_tree *tree = &EXT4_I(inode)->i_es_tree; struct rb_node **p = &tree->root.rb_node; struct rb_node *parent = NULL; struct extent_status *es; - ext4_lblk_t end = offset + len - 1; - - BUG_ON(end < offset); - es = tree->cache_es; - if (es && offset == (extent_status_end(es) + 1)) { - es_debug("cached by [%u/%u)\n", es->start, es->len); - es->len += len; - es = ext4_es_try_to_merge_right(tree, es); - goto out; - } else if (es && es->start == end + 1) { - es_debug("cached by [%u/%u)\n", es->start, es->len); - es->start = offset; - es->len += len; - es = ext4_es_try_to_merge_left(tree, es); - goto out; - } else if (es && es->start <= offset && - end <= extent_status_end(es)) { - es_debug("cached by [%u/%u)\n", es->start, es->len); - goto out; - } while (*p) { parent = *p; es = rb_entry(parent, struct extent_status, rb_node); - if (offset < es->start) { - if (es->start == end + 1) { - es->start = offset; - es->len += len; - es = ext4_es_try_to_merge_left(tree, es); + if (newes->es_lblk < es->es_lblk) { + if (ext4_es_can_be_merged(newes, es)) { + /* + * Here we can modify es_lblk directly + * because it isn't overlapped. + */ + es->es_lblk = newes->es_lblk; + es->es_len += newes->es_len; + if (ext4_es_is_written(es) || + ext4_es_is_unwritten(es)) + ext4_es_store_pblock(es, + newes->es_pblk); + es = ext4_es_try_to_merge_left(inode, es); goto out; } p = &(*p)->rb_left; - } else if (offset > extent_status_end(es)) { - if (offset == extent_status_end(es) + 1) { - es->len += len; - es = ext4_es_try_to_merge_right(tree, es); + } else if (newes->es_lblk > ext4_es_end(es)) { + if (ext4_es_can_be_merged(es, newes)) { + es->es_len += newes->es_len; + es = ext4_es_try_to_merge_right(inode, es); goto out; } p = &(*p)->rb_right; } else { - if (extent_status_end(es) <= end) - es->len = offset - es->start + len; - goto out; + BUG_ON(1); + return -EINVAL; } } - es = ext4_es_alloc_extent(offset, len); + es = ext4_es_alloc_extent(inode, newes->es_lblk, newes->es_len, + newes->es_pblk); if (!es) return -ENOMEM; rb_link_node(&es->rb_node, parent, p); @@ -385,85 +438,166 @@ out: } /* - * ext4_es_insert_extent() adds a space to a delayed extent tree. - * Caller holds inode->i_es_lock. + * ext4_es_insert_extent() adds a space to a extent status tree. * * ext4_es_insert_extent is called by ext4_da_write_begin and * ext4_es_remove_extent. * * Return 0 on success, error code on failure. */ -int ext4_es_insert_extent(struct inode *inode, ext4_lblk_t offset, - ext4_lblk_t len) +int ext4_es_insert_extent(struct inode *inode, ext4_lblk_t lblk, + ext4_lblk_t len, ext4_fsblk_t pblk, + unsigned long long status) { - struct ext4_es_tree *tree; + struct extent_status newes; + ext4_lblk_t end = lblk + len - 1; int err = 0; - trace_ext4_es_insert_extent(inode, offset, len); - es_debug("add [%u/%u) to extent status tree of inode %lu\n", - offset, len, inode->i_ino); + es_debug("add [%u/%u) %llu %llx to extent status tree of inode %lu\n", + lblk, len, pblk, status, inode->i_ino); + + if (!len) + return 0; + + BUG_ON(end < lblk); + + newes.es_lblk = lblk; + newes.es_len = len; + ext4_es_store_pblock(&newes, pblk); + ext4_es_store_status(&newes, status); + trace_ext4_es_insert_extent(inode, &newes); write_lock(&EXT4_I(inode)->i_es_lock); - tree = &EXT4_I(inode)->i_es_tree; - err = __es_insert_extent(tree, offset, len); + err = __es_remove_extent(inode, lblk, end); + if (err != 0) + goto error; + err = __es_insert_extent(inode, &newes); + +error: write_unlock(&EXT4_I(inode)->i_es_lock); + ext4_es_lru_add(inode); ext4_es_print_tree(inode); return err; } /* - * ext4_es_remove_extent() removes a space from a delayed extent tree. - * Caller holds inode->i_es_lock. + * ext4_es_lookup_extent() looks up an extent in extent status tree. * - * Return 0 on success, error code on failure. + * ext4_es_lookup_extent is called by ext4_map_blocks/ext4_da_map_blocks. + * + * Return: 1 on found, 0 on not */ -int ext4_es_remove_extent(struct inode *inode, ext4_lblk_t offset, - ext4_lblk_t len) +int ext4_es_lookup_extent(struct inode *inode, ext4_lblk_t lblk, + struct extent_status *es) { - struct rb_node *node; struct ext4_es_tree *tree; + struct extent_status *es1 = NULL; + struct rb_node *node; + int found = 0; + + trace_ext4_es_lookup_extent_enter(inode, lblk); + es_debug("lookup extent in block %u\n", lblk); + + tree = &EXT4_I(inode)->i_es_tree; + read_lock(&EXT4_I(inode)->i_es_lock); + + /* find extent in cache firstly */ + es->es_lblk = es->es_len = es->es_pblk = 0; + if (tree->cache_es) { + es1 = tree->cache_es; + if (in_range(lblk, es1->es_lblk, es1->es_len)) { + es_debug("%u cached by [%u/%u)\n", + lblk, es1->es_lblk, es1->es_len); + found = 1; + goto out; + } + } + + node = tree->root.rb_node; + while (node) { + es1 = rb_entry(node, struct extent_status, rb_node); + if (lblk < es1->es_lblk) + node = node->rb_left; + else if (lblk > ext4_es_end(es1)) + node = node->rb_right; + else { + found = 1; + break; + } + } + +out: + if (found) { + BUG_ON(!es1); + es->es_lblk = es1->es_lblk; + es->es_len = es1->es_len; + es->es_pblk = es1->es_pblk; + } + + read_unlock(&EXT4_I(inode)->i_es_lock); + + ext4_es_lru_add(inode); + trace_ext4_es_lookup_extent_exit(inode, es, found); + return found; +} + +static int __es_remove_extent(struct inode *inode, ext4_lblk_t lblk, + ext4_lblk_t end) +{ + struct ext4_es_tree *tree = &EXT4_I(inode)->i_es_tree; + struct rb_node *node; struct extent_status *es; struct extent_status orig_es; - ext4_lblk_t len1, len2, end; + ext4_lblk_t len1, len2; + ext4_fsblk_t block; int err = 0; - trace_ext4_es_remove_extent(inode, offset, len); - es_debug("remove [%u/%u) from extent status tree of inode %lu\n", - offset, len, inode->i_ino); - - end = offset + len - 1; - BUG_ON(end < offset); - write_lock(&EXT4_I(inode)->i_es_lock); - tree = &EXT4_I(inode)->i_es_tree; - es = __es_tree_search(&tree->root, offset); + es = __es_tree_search(&tree->root, lblk); if (!es) goto out; - if (es->start > end) + if (es->es_lblk > end) goto out; /* Simply invalidate cache_es. */ tree->cache_es = NULL; - orig_es.start = es->start; - orig_es.len = es->len; - len1 = offset > es->start ? offset - es->start : 0; - len2 = extent_status_end(es) > end ? - extent_status_end(es) - end : 0; + orig_es.es_lblk = es->es_lblk; + orig_es.es_len = es->es_len; + orig_es.es_pblk = es->es_pblk; + + len1 = lblk > es->es_lblk ? lblk - es->es_lblk : 0; + len2 = ext4_es_end(es) > end ? ext4_es_end(es) - end : 0; if (len1 > 0) - es->len = len1; + es->es_len = len1; if (len2 > 0) { if (len1 > 0) { - err = __es_insert_extent(tree, end + 1, len2); + struct extent_status newes; + + newes.es_lblk = end + 1; + newes.es_len = len2; + if (ext4_es_is_written(&orig_es) || + ext4_es_is_unwritten(&orig_es)) { + block = ext4_es_pblock(&orig_es) + + orig_es.es_len - len2; + ext4_es_store_pblock(&newes, block); + } + ext4_es_store_status(&newes, ext4_es_status(&orig_es)); + err = __es_insert_extent(inode, &newes); if (err) { - es->start = orig_es.start; - es->len = orig_es.len; + es->es_lblk = orig_es.es_lblk; + es->es_len = orig_es.es_len; goto out; } } else { - es->start = end + 1; - es->len = len2; + es->es_lblk = end + 1; + es->es_len = len2; + if (ext4_es_is_written(es) || + ext4_es_is_unwritten(es)) { + block = orig_es.es_pblk + orig_es.es_len - len2; + ext4_es_store_pblock(es, block); + } } goto out; } @@ -476,10 +610,10 @@ int ext4_es_remove_extent(struct inode *inode, ext4_lblk_t offset, es = NULL; } - while (es && extent_status_end(es) <= end) { + while (es && ext4_es_end(es) <= end) { node = rb_next(&es->rb_node); rb_erase(&es->rb_node, &tree->root); - ext4_es_free_extent(es); + ext4_es_free_extent(inode, es); if (!node) { es = NULL; break; @@ -487,14 +621,183 @@ int ext4_es_remove_extent(struct inode *inode, ext4_lblk_t offset, es = rb_entry(node, struct extent_status, rb_node); } - if (es && es->start < end + 1) { - len1 = extent_status_end(es) - end; - es->start = end + 1; - es->len = len1; + if (es && es->es_lblk < end + 1) { + ext4_lblk_t orig_len = es->es_len; + + len1 = ext4_es_end(es) - end; + es->es_lblk = end + 1; + es->es_len = len1; + if (ext4_es_is_written(es) || ext4_es_is_unwritten(es)) { + block = es->es_pblk + orig_len - len1; + ext4_es_store_pblock(es, block); + } } out: + return err; +} + +/* + * ext4_es_remove_extent() removes a space from a extent status tree. + * + * Return 0 on success, error code on failure. + */ +int ext4_es_remove_extent(struct inode *inode, ext4_lblk_t lblk, + ext4_lblk_t len) +{ + ext4_lblk_t end; + int err = 0; + + trace_ext4_es_remove_extent(inode, lblk, len); + es_debug("remove [%u/%u) from extent status tree of inode %lu\n", + lblk, len, inode->i_ino); + + if (!len) + return err; + + end = lblk + len - 1; + BUG_ON(end < lblk); + + write_lock(&EXT4_I(inode)->i_es_lock); + err = __es_remove_extent(inode, lblk, end); write_unlock(&EXT4_I(inode)->i_es_lock); ext4_es_print_tree(inode); return err; } + +static int ext4_es_shrink(struct shrinker *shrink, struct shrink_control *sc) +{ + struct ext4_sb_info *sbi = container_of(shrink, + struct ext4_sb_info, s_es_shrinker); + struct ext4_inode_info *ei; + struct list_head *cur, *tmp, scanned; + int nr_to_scan = sc->nr_to_scan; + int ret, nr_shrunk = 0; + + trace_ext4_es_shrink_enter(sbi->s_sb, nr_to_scan); + + if (!nr_to_scan) + return ext4_es_reclaim_extents_count(sbi->s_sb); + + INIT_LIST_HEAD(&scanned); + + spin_lock(&sbi->s_es_lru_lock); + list_for_each_safe(cur, tmp, &sbi->s_es_lru) { + list_move_tail(cur, &scanned); + + ei = list_entry(cur, struct ext4_inode_info, i_es_lru); + + read_lock(&ei->i_es_lock); + if (ei->i_es_lru_nr == 0) { + read_unlock(&ei->i_es_lock); + continue; + } + read_unlock(&ei->i_es_lock); + + write_lock(&ei->i_es_lock); + ret = __es_try_to_reclaim_extents(ei, nr_to_scan); + write_unlock(&ei->i_es_lock); + + nr_shrunk += ret; + nr_to_scan -= ret; + if (nr_to_scan == 0) + break; + } + list_splice_tail(&scanned, &sbi->s_es_lru); + spin_unlock(&sbi->s_es_lru_lock); + trace_ext4_es_shrink_exit(sbi->s_sb, nr_shrunk); + + return ext4_es_reclaim_extents_count(sbi->s_sb); +} + +void ext4_es_register_shrinker(struct super_block *sb) +{ + struct ext4_sb_info *sbi; + + sbi = EXT4_SB(sb); + INIT_LIST_HEAD(&sbi->s_es_lru); + spin_lock_init(&sbi->s_es_lru_lock); + sbi->s_es_shrinker.shrink = ext4_es_shrink; + sbi->s_es_shrinker.seeks = DEFAULT_SEEKS; + register_shrinker(&sbi->s_es_shrinker); +} + +void ext4_es_unregister_shrinker(struct super_block *sb) +{ + unregister_shrinker(&EXT4_SB(sb)->s_es_shrinker); +} + +void ext4_es_lru_add(struct inode *inode) +{ + struct ext4_inode_info *ei = EXT4_I(inode); + struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); + + spin_lock(&sbi->s_es_lru_lock); + if (list_empty(&ei->i_es_lru)) + list_add_tail(&ei->i_es_lru, &sbi->s_es_lru); + else + list_move_tail(&ei->i_es_lru, &sbi->s_es_lru); + spin_unlock(&sbi->s_es_lru_lock); +} + +void ext4_es_lru_del(struct inode *inode) +{ + struct ext4_inode_info *ei = EXT4_I(inode); + struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); + + spin_lock(&sbi->s_es_lru_lock); + if (!list_empty(&ei->i_es_lru)) + list_del_init(&ei->i_es_lru); + spin_unlock(&sbi->s_es_lru_lock); +} + +static int ext4_es_reclaim_extents_count(struct super_block *sb) +{ + struct ext4_sb_info *sbi = EXT4_SB(sb); + struct ext4_inode_info *ei; + struct list_head *cur; + int nr_cached = 0; + + spin_lock(&sbi->s_es_lru_lock); + list_for_each(cur, &sbi->s_es_lru) { + ei = list_entry(cur, struct ext4_inode_info, i_es_lru); + read_lock(&ei->i_es_lock); + nr_cached += ei->i_es_lru_nr; + read_unlock(&ei->i_es_lock); + } + spin_unlock(&sbi->s_es_lru_lock); + trace_ext4_es_reclaim_extents_count(sb, nr_cached); + return nr_cached; +} + +static int __es_try_to_reclaim_extents(struct ext4_inode_info *ei, + int nr_to_scan) +{ + struct inode *inode = &ei->vfs_inode; + struct ext4_es_tree *tree = &ei->i_es_tree; + struct rb_node *node; + struct extent_status *es; + int nr_shrunk = 0; + + if (ei->i_es_lru_nr == 0) + return 0; + + node = rb_first(&tree->root); + while (node != NULL) { + es = rb_entry(node, struct extent_status, rb_node); + node = rb_next(&es->rb_node); + /* + * We can't reclaim delayed extent from status tree because + * fiemap, bigallic, and seek_data/hole need to use it. + */ + if (!ext4_es_is_delayed(es)) { + rb_erase(&es->rb_node, &tree->root); + ext4_es_free_extent(inode, es); + nr_shrunk++; + if (--nr_to_scan == 0) + break; + } + } + tree->cache_es = NULL; + return nr_shrunk; +} |