diff options
Diffstat (limited to 'fs/ext4/extents_status.c')
| -rw-r--r-- | fs/ext4/extents_status.c | 2309 |
1 files changed, 2309 insertions, 0 deletions
diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c new file mode 100644 index 0000000000..f4b50652f0 --- /dev/null +++ b/fs/ext4/extents_status.c @@ -0,0 +1,2309 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * fs/ext4/extents_status.c + * + * Written by Yongqiang Yang <xiaoqiangnk@gmail.com> + * Modified by + * Allison Henderson <achender@linux.vnet.ibm.com> + * Hugh Dickins <hughd@google.com> + * Zheng Liu <wenqing.lz@taobao.com> + * + * Ext4 extents status tree core functions. + */ +#include <linux/list_sort.h> +#include <linux/proc_fs.h> +#include <linux/seq_file.h> +#include "ext4.h" + +#include <trace/events/ext4.h> + +/* + * According to previous discussion in Ext4 Developer Workshop, we + * will introduce a new structure called io tree to track all extent + * status in order to solve some problems that we have met + * (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 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 first commit. But for better understand + * what it does, it has been rename to extent status tree. + * + * 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. + */ + +/* + * Extent status tree implementation for ext4. + * + * + * ========================================================================== + * Extent status tree tracks all extent status. + * + * 1. Why we need to implement extent status tree? + * + * 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, 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 extent status tree. + * -- FIEMAP + * FIEMAP looks up page cache to identify delayed allocations from holes. + * + * -- SEEK_HOLE/DATA + * SEEK_HOLE/DATA has the same problem as FIEMAP. + * + * -- bigalloc + * bigalloc looks up page cache to figure out if a block is + * already under delayed allocation or not to determine whether + * quota reserving is needed for the cluster. + * + * -- 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 consuming. + * + * 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 extent tree. + * + * + * ========================================================================== + * 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. + * + * -- 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. + * + * -- 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. + * + * -- race on a extent status tree + * Extent status tree is protected by 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 + * + * -- 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. + * + * -- gain + * 2. Code is much simpler, more readable, more maintainable and + * more efficient. + * + * + * ========================================================================== + * 4. TODO list + * + * -- Refactor delayed space reservation + * + * -- Extent-level locking + */ + +static struct kmem_cache *ext4_es_cachep; +static struct kmem_cache *ext4_pending_cachep; + +static int __es_insert_extent(struct inode *inode, struct extent_status *newes, + struct extent_status *prealloc); +static int __es_remove_extent(struct inode *inode, ext4_lblk_t lblk, + ext4_lblk_t end, int *reserved, + struct extent_status *prealloc); +static int es_reclaim_extents(struct ext4_inode_info *ei, int *nr_to_scan); +static int __es_shrink(struct ext4_sb_info *sbi, int nr_to_scan, + struct ext4_inode_info *locked_ei); +static int __revise_pending(struct inode *inode, ext4_lblk_t lblk, + ext4_lblk_t len, + struct pending_reservation **prealloc); + +int __init ext4_init_es(void) +{ + ext4_es_cachep = KMEM_CACHE(extent_status, SLAB_RECLAIM_ACCOUNT); + if (ext4_es_cachep == NULL) + return -ENOMEM; + return 0; +} + +void ext4_exit_es(void) +{ + kmem_cache_destroy(ext4_es_cachep); +} + +void ext4_es_init_tree(struct ext4_es_tree *tree) +{ + tree->root = RB_ROOT; + tree->cache_es = NULL; +} + +#ifdef ES_DEBUG__ +static void ext4_es_print_tree(struct inode *inode) +{ + struct ext4_es_tree *tree; + struct rb_node *node; + + printk(KERN_DEBUG "status extents for inode %lu:", inode->i_ino); + tree = &EXT4_I(inode)->i_es_tree; + node = rb_first(&tree->root); + while (node) { + struct extent_status *es; + es = rb_entry(node, struct extent_status, rb_node); + printk(KERN_DEBUG " [%u/%u) %llu %x", + es->es_lblk, es->es_len, + ext4_es_pblock(es), ext4_es_status(es)); + node = rb_next(node); + } + printk(KERN_DEBUG "\n"); +} +#else +#define ext4_es_print_tree(inode) +#endif + +static inline ext4_lblk_t ext4_es_end(struct extent_status *es) +{ + BUG_ON(es->es_lblk + es->es_len < es->es_lblk); + return es->es_lblk + es->es_len - 1; +} + +/* + * search through the tree for an delayed extent with a given offset. If + * it can't be found, try to find next extent. + */ +static struct extent_status *__es_tree_search(struct rb_root *root, + 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 (lblk < es->es_lblk) + node = node->rb_left; + else if (lblk > ext4_es_end(es)) + node = node->rb_right; + else + return es; + } + + if (es && lblk < es->es_lblk) + return 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; + } + + return NULL; +} + +/* + * ext4_es_find_extent_range - find extent with specified status within block + * range or next extent following block range in + * extents status tree + * + * @inode - file containing the range + * @matching_fn - pointer to function that matches extents with desired status + * @lblk - logical block defining start of range + * @end - logical block defining end of range + * @es - extent found, if any + * + * Find the first extent within the block range specified by @lblk and @end + * in the extents status tree that satisfies @matching_fn. If a match + * is found, it's returned in @es. If not, and a matching extent is found + * beyond the block range, it's returned in @es. If no match is found, an + * extent is returned in @es whose es_lblk, es_len, and es_pblk components + * are 0. + */ +static void __es_find_extent_range(struct inode *inode, + int (*matching_fn)(struct extent_status *es), + ext4_lblk_t lblk, ext4_lblk_t end, + struct extent_status *es) +{ + struct ext4_es_tree *tree = NULL; + struct extent_status *es1 = NULL; + struct rb_node *node; + + WARN_ON(es == NULL); + WARN_ON(end < lblk); + + tree = &EXT4_I(inode)->i_es_tree; + + /* see if the extent has been cached */ + es->es_lblk = es->es_len = es->es_pblk = 0; + es1 = READ_ONCE(tree->cache_es); + if (es1 && in_range(lblk, es1->es_lblk, es1->es_len)) { + es_debug("%u cached by [%u/%u) %llu %x\n", + lblk, es1->es_lblk, es1->es_len, + ext4_es_pblock(es1), ext4_es_status(es1)); + goto out; + } + + es1 = __es_tree_search(&tree->root, lblk); + +out: + if (es1 && !matching_fn(es1)) { + while ((node = rb_next(&es1->rb_node)) != NULL) { + es1 = rb_entry(node, struct extent_status, rb_node); + if (es1->es_lblk > end) { + es1 = NULL; + break; + } + if (matching_fn(es1)) + break; + } + } + + if (es1 && matching_fn(es1)) { + WRITE_ONCE(tree->cache_es, es1); + es->es_lblk = es1->es_lblk; + es->es_len = es1->es_len; + es->es_pblk = es1->es_pblk; + } + +} + +/* + * Locking for __es_find_extent_range() for external use + */ +void ext4_es_find_extent_range(struct inode *inode, + int (*matching_fn)(struct extent_status *es), + ext4_lblk_t lblk, ext4_lblk_t end, + struct extent_status *es) +{ + if (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY) + return; + + trace_ext4_es_find_extent_range_enter(inode, lblk); + + read_lock(&EXT4_I(inode)->i_es_lock); + __es_find_extent_range(inode, matching_fn, lblk, end, es); + read_unlock(&EXT4_I(inode)->i_es_lock); + + trace_ext4_es_find_extent_range_exit(inode, es); +} + +/* + * __es_scan_range - search block range for block with specified status + * in extents status tree + * + * @inode - file containing the range + * @matching_fn - pointer to function that matches extents with desired status + * @lblk - logical block defining start of range + * @end - logical block defining end of range + * + * Returns true if at least one block in the specified block range satisfies + * the criterion specified by @matching_fn, and false if not. If at least + * one extent has the specified status, then there is at least one block + * in the cluster with that status. Should only be called by code that has + * taken i_es_lock. + */ +static bool __es_scan_range(struct inode *inode, + int (*matching_fn)(struct extent_status *es), + ext4_lblk_t start, ext4_lblk_t end) +{ + struct extent_status es; + + __es_find_extent_range(inode, matching_fn, start, end, &es); + if (es.es_len == 0) + return false; /* no matching extent in the tree */ + else if (es.es_lblk <= start && + start < es.es_lblk + es.es_len) + return true; + else if (start <= es.es_lblk && es.es_lblk <= end) + return true; + else + return false; +} +/* + * Locking for __es_scan_range() for external use + */ +bool ext4_es_scan_range(struct inode *inode, + int (*matching_fn)(struct extent_status *es), + ext4_lblk_t lblk, ext4_lblk_t end) +{ + bool ret; + + if (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY) + return false; + + read_lock(&EXT4_I(inode)->i_es_lock); + ret = __es_scan_range(inode, matching_fn, lblk, end); + read_unlock(&EXT4_I(inode)->i_es_lock); + + return ret; +} + +/* + * __es_scan_clu - search cluster for block with specified status in + * extents status tree + * + * @inode - file containing the cluster + * @matching_fn - pointer to function that matches extents with desired status + * @lblk - logical block in cluster to be searched + * + * Returns true if at least one extent in the cluster containing @lblk + * satisfies the criterion specified by @matching_fn, and false if not. If at + * least one extent has the specified status, then there is at least one block + * in the cluster with that status. Should only be called by code that has + * taken i_es_lock. + */ +static bool __es_scan_clu(struct inode *inode, + int (*matching_fn)(struct extent_status *es), + ext4_lblk_t lblk) +{ + struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); + ext4_lblk_t lblk_start, lblk_end; + + lblk_start = EXT4_LBLK_CMASK(sbi, lblk); + lblk_end = lblk_start + sbi->s_cluster_ratio - 1; + + return __es_scan_range(inode, matching_fn, lblk_start, lblk_end); +} + +/* + * Locking for __es_scan_clu() for external use + */ +bool ext4_es_scan_clu(struct inode *inode, + int (*matching_fn)(struct extent_status *es), + ext4_lblk_t lblk) +{ + bool ret; + + if (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY) + return false; + + read_lock(&EXT4_I(inode)->i_es_lock); + ret = __es_scan_clu(inode, matching_fn, lblk); + read_unlock(&EXT4_I(inode)->i_es_lock); + + return ret; +} + +static void ext4_es_list_add(struct inode *inode) +{ + struct ext4_inode_info *ei = EXT4_I(inode); + struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); + + if (!list_empty(&ei->i_es_list)) + return; + + spin_lock(&sbi->s_es_lock); + if (list_empty(&ei->i_es_list)) { + list_add_tail(&ei->i_es_list, &sbi->s_es_list); + sbi->s_es_nr_inode++; + } + spin_unlock(&sbi->s_es_lock); +} + +static void ext4_es_list_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_lock); + if (!list_empty(&ei->i_es_list)) { + list_del_init(&ei->i_es_list); + sbi->s_es_nr_inode--; + WARN_ON_ONCE(sbi->s_es_nr_inode < 0); + } + spin_unlock(&sbi->s_es_lock); +} + +static inline struct pending_reservation *__alloc_pending(bool nofail) +{ + if (!nofail) + return kmem_cache_alloc(ext4_pending_cachep, GFP_ATOMIC); + + return kmem_cache_zalloc(ext4_pending_cachep, GFP_KERNEL | __GFP_NOFAIL); +} + +static inline void __free_pending(struct pending_reservation *pr) +{ + kmem_cache_free(ext4_pending_cachep, pr); +} + +/* + * Returns true if we cannot fail to allocate memory for this extent_status + * entry and cannot reclaim it until its status changes. + */ +static inline bool ext4_es_must_keep(struct extent_status *es) +{ + /* fiemap, bigalloc, and seek_data/hole need to use it. */ + if (ext4_es_is_delayed(es)) + return true; + + return false; +} + +static inline struct extent_status *__es_alloc_extent(bool nofail) +{ + if (!nofail) + return kmem_cache_alloc(ext4_es_cachep, GFP_ATOMIC); + + return kmem_cache_zalloc(ext4_es_cachep, GFP_KERNEL | __GFP_NOFAIL); +} + +static void ext4_es_init_extent(struct inode *inode, struct extent_status *es, + ext4_lblk_t lblk, ext4_lblk_t len, ext4_fsblk_t pblk) +{ + es->es_lblk = lblk; + es->es_len = len; + es->es_pblk = pblk; + + /* We never try to reclaim a must kept extent, so we don't count it. */ + if (!ext4_es_must_keep(es)) { + if (!EXT4_I(inode)->i_es_shk_nr++) + ext4_es_list_add(inode); + percpu_counter_inc(&EXT4_SB(inode->i_sb)-> + s_es_stats.es_stats_shk_cnt); + } + + EXT4_I(inode)->i_es_all_nr++; + percpu_counter_inc(&EXT4_SB(inode->i_sb)->s_es_stats.es_stats_all_cnt); +} + +static inline void __es_free_extent(struct extent_status *es) +{ + kmem_cache_free(ext4_es_cachep, es); +} + +static void ext4_es_free_extent(struct inode *inode, struct extent_status *es) +{ + EXT4_I(inode)->i_es_all_nr--; + percpu_counter_dec(&EXT4_SB(inode->i_sb)->s_es_stats.es_stats_all_cnt); + + /* Decrease the shrink counter when we can reclaim the extent. */ + if (!ext4_es_must_keep(es)) { + BUG_ON(EXT4_I(inode)->i_es_shk_nr == 0); + if (!--EXT4_I(inode)->i_es_shk_nr) + ext4_es_list_del(inode); + percpu_counter_dec(&EXT4_SB(inode->i_sb)-> + s_es_stats.es_stats_shk_cnt); + } + + __es_free_extent(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 (ext4_es_type(es1) != ext4_es_type(es2)) + return 0; + + if (((__u64) es1->es_len) + es2->es_len > EXT_MAX_BLOCKS) { + pr_warn("ES assertion failed when merging extents. " + "The sum of lengths of es1 (%d) and es2 (%d) " + "is bigger than allowed file size (%d)\n", + es1->es_len, es2->es_len, EXT_MAX_BLOCKS); + WARN_ON(1); + return 0; + } + + if (((__u64) es1->es_lblk) + es1->es_len != es2->es_lblk) + 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 1; + + if (ext4_es_is_hole(es1)) + return 1; + + /* we need to check delayed extent is without unwritten status */ + if (ext4_es_is_delayed(es1) && !ext4_es_is_unwritten(es1)) + return 1; + + return 0; +} + +static struct extent_status * +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; + + node = rb_prev(&es->rb_node); + if (!node) + return es; + + es1 = rb_entry(node, struct extent_status, rb_node); + if (ext4_es_can_be_merged(es1, es)) { + es1->es_len += es->es_len; + if (ext4_es_is_referenced(es)) + ext4_es_set_referenced(es1); + rb_erase(&es->rb_node, &tree->root); + ext4_es_free_extent(inode, es); + es = es1; + } + + return es; +} + +static struct extent_status * +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; + + node = rb_next(&es->rb_node); + if (!node) + return es; + + es1 = rb_entry(node, struct extent_status, rb_node); + if (ext4_es_can_be_merged(es, es1)) { + es->es_len += es1->es_len; + if (ext4_es_is_referenced(es1)) + ext4_es_set_referenced(es); + rb_erase(node, &tree->root); + ext4_es_free_extent(inode, es1); + } + + return es; +} + +#ifdef ES_AGGRESSIVE_TEST +#include "ext4_extents.h" /* Needed when ES_AGGRESSIVE_TEST is defined */ + +static void ext4_es_insert_extent_ext_check(struct inode *inode, + struct extent_status *es) +{ + struct ext4_ext_path *path = NULL; + struct ext4_extent *ex; + ext4_lblk_t ee_block; + ext4_fsblk_t ee_start; + unsigned short ee_len; + int depth, ee_status, es_status; + + path = ext4_find_extent(inode, es->es_lblk, NULL, EXT4_EX_NOCACHE); + if (IS_ERR(path)) + return; + + depth = ext_depth(inode); + ex = path[depth].p_ext; + + if (ex) { + + ee_block = le32_to_cpu(ex->ee_block); + ee_start = ext4_ext_pblock(ex); + ee_len = ext4_ext_get_actual_len(ex); + + ee_status = ext4_ext_is_unwritten(ex) ? 1 : 0; + es_status = ext4_es_is_unwritten(es) ? 1 : 0; + + /* + * Make sure ex and es are not overlap when we try to insert + * a delayed/hole extent. + */ + if (!ext4_es_is_written(es) && !ext4_es_is_unwritten(es)) { + if (in_range(es->es_lblk, ee_block, ee_len)) { + pr_warn("ES insert assertion failed for " + "inode: %lu we can find an extent " + "at block [%d/%d/%llu/%c], but we " + "want to add a delayed/hole extent " + "[%d/%d/%llu/%x]\n", + inode->i_ino, ee_block, ee_len, + ee_start, ee_status ? 'u' : 'w', + es->es_lblk, es->es_len, + ext4_es_pblock(es), ext4_es_status(es)); + } + goto out; + } + + /* + * We don't check ee_block == es->es_lblk, etc. because es + * might be a part of whole extent, vice versa. + */ + if (es->es_lblk < ee_block || + ext4_es_pblock(es) != ee_start + es->es_lblk - ee_block) { + pr_warn("ES insert assertion failed for inode: %lu " + "ex_status [%d/%d/%llu/%c] != " + "es_status [%d/%d/%llu/%c]\n", inode->i_ino, + ee_block, ee_len, ee_start, + ee_status ? 'u' : 'w', es->es_lblk, es->es_len, + ext4_es_pblock(es), es_status ? 'u' : 'w'); + goto out; + } + + if (ee_status ^ es_status) { + pr_warn("ES insert assertion failed for inode: %lu " + "ex_status [%d/%d/%llu/%c] != " + "es_status [%d/%d/%llu/%c]\n", inode->i_ino, + ee_block, ee_len, ee_start, + ee_status ? 'u' : 'w', es->es_lblk, es->es_len, + ext4_es_pblock(es), es_status ? 'u' : 'w'); + } + } else { + /* + * We can't find an extent on disk. So we need to make sure + * that we don't want to add an written/unwritten extent. + */ + if (!ext4_es_is_delayed(es) && !ext4_es_is_hole(es)) { + pr_warn("ES insert assertion failed for inode: %lu " + "can't find an extent at block %d but we want " + "to add a written/unwritten extent " + "[%d/%d/%llu/%x]\n", inode->i_ino, + es->es_lblk, es->es_lblk, es->es_len, + ext4_es_pblock(es), ext4_es_status(es)); + } + } +out: + ext4_free_ext_path(path); +} + +static void ext4_es_insert_extent_ind_check(struct inode *inode, + struct extent_status *es) +{ + struct ext4_map_blocks map; + int retval; + + /* + * Here we call ext4_ind_map_blocks to lookup a block mapping because + * 'Indirect' structure is defined in indirect.c. So we couldn't + * access direct/indirect tree from outside. It is too dirty to define + * this function in indirect.c file. + */ + + map.m_lblk = es->es_lblk; + map.m_len = es->es_len; + + retval = ext4_ind_map_blocks(NULL, inode, &map, 0); + if (retval > 0) { + if (ext4_es_is_delayed(es) || ext4_es_is_hole(es)) { + /* + * We want to add a delayed/hole extent but this + * block has been allocated. + */ + pr_warn("ES insert assertion failed for inode: %lu " + "We can find blocks but we want to add a " + "delayed/hole extent [%d/%d/%llu/%x]\n", + inode->i_ino, es->es_lblk, es->es_len, + ext4_es_pblock(es), ext4_es_status(es)); + return; + } else if (ext4_es_is_written(es)) { + if (retval != es->es_len) { + pr_warn("ES insert assertion failed for " + "inode: %lu retval %d != es_len %d\n", + inode->i_ino, retval, es->es_len); + return; + } + if (map.m_pblk != ext4_es_pblock(es)) { + pr_warn("ES insert assertion failed for " + "inode: %lu m_pblk %llu != " + "es_pblk %llu\n", + inode->i_ino, map.m_pblk, + ext4_es_pblock(es)); + return; + } + } else { + /* + * We don't need to check unwritten extent because + * indirect-based file doesn't have it. + */ + BUG(); + } + } else if (retval == 0) { + if (ext4_es_is_written(es)) { + pr_warn("ES insert assertion failed for inode: %lu " + "We can't find the block but we want to add " + "a written extent [%d/%d/%llu/%x]\n", + inode->i_ino, es->es_lblk, es->es_len, + ext4_es_pblock(es), ext4_es_status(es)); + return; + } + } +} + +static inline void ext4_es_insert_extent_check(struct inode *inode, + struct extent_status *es) +{ + /* + * We don't need to worry about the race condition because + * caller takes i_data_sem locking. + */ + BUG_ON(!rwsem_is_locked(&EXT4_I(inode)->i_data_sem)); + if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) + ext4_es_insert_extent_ext_check(inode, es); + else + ext4_es_insert_extent_ind_check(inode, es); +} +#else +static inline void ext4_es_insert_extent_check(struct inode *inode, + struct extent_status *es) +{ +} +#endif + +static int __es_insert_extent(struct inode *inode, struct extent_status *newes, + struct extent_status *prealloc) +{ + 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; + + while (*p) { + parent = *p; + es = rb_entry(parent, struct extent_status, rb_node); + + 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 (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 { + BUG(); + return -EINVAL; + } + } + + if (prealloc) + es = prealloc; + else + es = __es_alloc_extent(false); + if (!es) + return -ENOMEM; + ext4_es_init_extent(inode, es, newes->es_lblk, newes->es_len, + newes->es_pblk); + + rb_link_node(&es->rb_node, parent, p); + rb_insert_color(&es->rb_node, &tree->root); + +out: + tree->cache_es = es; + return 0; +} + +/* + * ext4_es_insert_extent() adds information to an inode's extent + * status tree. + */ +void ext4_es_insert_extent(struct inode *inode, ext4_lblk_t lblk, + ext4_lblk_t len, ext4_fsblk_t pblk, + unsigned int status) +{ + struct extent_status newes; + ext4_lblk_t end = lblk + len - 1; + int err1 = 0, err2 = 0, err3 = 0; + struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); + struct extent_status *es1 = NULL; + struct extent_status *es2 = NULL; + struct pending_reservation *pr = NULL; + bool revise_pending = false; + + if (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY) + return; + + es_debug("add [%u/%u) %llu %x to extent status tree of inode %lu\n", + lblk, len, pblk, status, inode->i_ino); + + if (!len) + return; + + BUG_ON(end < lblk); + + if ((status & EXTENT_STATUS_DELAYED) && + (status & EXTENT_STATUS_WRITTEN)) { + ext4_warning(inode->i_sb, "Inserting extent [%u/%u] as " + " delayed and written which can potentially " + " cause data loss.", lblk, len); + WARN_ON(1); + } + + newes.es_lblk = lblk; + newes.es_len = len; + ext4_es_store_pblock_status(&newes, pblk, status); + trace_ext4_es_insert_extent(inode, &newes); + + ext4_es_insert_extent_check(inode, &newes); + + revise_pending = sbi->s_cluster_ratio > 1 && + test_opt(inode->i_sb, DELALLOC) && + (status & (EXTENT_STATUS_WRITTEN | + EXTENT_STATUS_UNWRITTEN)); +retry: + if (err1 && !es1) + es1 = __es_alloc_extent(true); + if ((err1 || err2) && !es2) + es2 = __es_alloc_extent(true); + if ((err1 || err2 || err3) && revise_pending && !pr) + pr = __alloc_pending(true); + write_lock(&EXT4_I(inode)->i_es_lock); + + err1 = __es_remove_extent(inode, lblk, end, NULL, es1); + if (err1 != 0) + goto error; + /* Free preallocated extent if it didn't get used. */ + if (es1) { + if (!es1->es_len) + __es_free_extent(es1); + es1 = NULL; + } + + err2 = __es_insert_extent(inode, &newes, es2); + if (err2 == -ENOMEM && !ext4_es_must_keep(&newes)) + err2 = 0; + if (err2 != 0) + goto error; + /* Free preallocated extent if it didn't get used. */ + if (es2) { + if (!es2->es_len) + __es_free_extent(es2); + es2 = NULL; + } + + if (revise_pending) { + err3 = __revise_pending(inode, lblk, len, &pr); + if (err3 != 0) + goto error; + if (pr) { + __free_pending(pr); + pr = NULL; + } + } +error: + write_unlock(&EXT4_I(inode)->i_es_lock); + if (err1 || err2 || err3) + goto retry; + + ext4_es_print_tree(inode); + return; +} + +/* + * ext4_es_cache_extent() inserts information into the extent status + * tree if and only if there isn't information about the range in + * question already. + */ +void ext4_es_cache_extent(struct inode *inode, ext4_lblk_t lblk, + ext4_lblk_t len, ext4_fsblk_t pblk, + unsigned int status) +{ + struct extent_status *es; + struct extent_status newes; + ext4_lblk_t end = lblk + len - 1; + + if (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY) + return; + + newes.es_lblk = lblk; + newes.es_len = len; + ext4_es_store_pblock_status(&newes, pblk, status); + trace_ext4_es_cache_extent(inode, &newes); + + if (!len) + return; + + BUG_ON(end < lblk); + + write_lock(&EXT4_I(inode)->i_es_lock); + + es = __es_tree_search(&EXT4_I(inode)->i_es_tree.root, lblk); + if (!es || es->es_lblk > end) + __es_insert_extent(inode, &newes, NULL); + write_unlock(&EXT4_I(inode)->i_es_lock); +} + +/* + * ext4_es_lookup_extent() looks up an extent in extent status tree. + * + * ext4_es_lookup_extent is called by ext4_map_blocks/ext4_da_map_blocks. + * + * Return: 1 on found, 0 on not + */ +int ext4_es_lookup_extent(struct inode *inode, ext4_lblk_t lblk, + ext4_lblk_t *next_lblk, + struct extent_status *es) +{ + struct ext4_es_tree *tree; + struct ext4_es_stats *stats; + struct extent_status *es1 = NULL; + struct rb_node *node; + int found = 0; + + if (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY) + return 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; + es1 = READ_ONCE(tree->cache_es); + if (es1 && 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: + stats = &EXT4_SB(inode->i_sb)->s_es_stats; + if (found) { + BUG_ON(!es1); + es->es_lblk = es1->es_lblk; + es->es_len = es1->es_len; + es->es_pblk = es1->es_pblk; + if (!ext4_es_is_referenced(es1)) + ext4_es_set_referenced(es1); + percpu_counter_inc(&stats->es_stats_cache_hits); + if (next_lblk) { + node = rb_next(&es1->rb_node); + if (node) { + es1 = rb_entry(node, struct extent_status, + rb_node); + *next_lblk = es1->es_lblk; + } else + *next_lblk = 0; + } + } else { + percpu_counter_inc(&stats->es_stats_cache_misses); + } + + read_unlock(&EXT4_I(inode)->i_es_lock); + + trace_ext4_es_lookup_extent_exit(inode, es, found); + return found; +} + +struct rsvd_count { + int ndelonly; + bool first_do_lblk_found; + ext4_lblk_t first_do_lblk; + ext4_lblk_t last_do_lblk; + struct extent_status *left_es; + bool partial; + ext4_lblk_t lclu; +}; + +/* + * init_rsvd - initialize reserved count data before removing block range + * in file from extent status tree + * + * @inode - file containing range + * @lblk - first block in range + * @es - pointer to first extent in range + * @rc - pointer to reserved count data + * + * Assumes es is not NULL + */ +static void init_rsvd(struct inode *inode, ext4_lblk_t lblk, + struct extent_status *es, struct rsvd_count *rc) +{ + struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); + struct rb_node *node; + + rc->ndelonly = 0; + + /* + * for bigalloc, note the first delonly block in the range has not + * been found, record the extent containing the block to the left of + * the region to be removed, if any, and note that there's no partial + * cluster to track + */ + if (sbi->s_cluster_ratio > 1) { + rc->first_do_lblk_found = false; + if (lblk > es->es_lblk) { + rc->left_es = es; + } else { + node = rb_prev(&es->rb_node); + rc->left_es = node ? rb_entry(node, + struct extent_status, + rb_node) : NULL; + } + rc->partial = false; + } +} + +/* + * count_rsvd - count the clusters containing delayed and not unwritten + * (delonly) blocks in a range within an extent and add to + * the running tally in rsvd_count + * + * @inode - file containing extent + * @lblk - first block in range + * @len - length of range in blocks + * @es - pointer to extent containing clusters to be counted + * @rc - pointer to reserved count data + * + * Tracks partial clusters found at the beginning and end of extents so + * they aren't overcounted when they span adjacent extents + */ +static void count_rsvd(struct inode *inode, ext4_lblk_t lblk, long len, + struct extent_status *es, struct rsvd_count *rc) +{ + struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); + ext4_lblk_t i, end, nclu; + + if (!ext4_es_is_delonly(es)) + return; + + WARN_ON(len <= 0); + + if (sbi->s_cluster_ratio == 1) { + rc->ndelonly += (int) len; + return; + } + + /* bigalloc */ + + i = (lblk < es->es_lblk) ? es->es_lblk : lblk; + end = lblk + (ext4_lblk_t) len - 1; + end = (end > ext4_es_end(es)) ? ext4_es_end(es) : end; + + /* record the first block of the first delonly extent seen */ + if (!rc->first_do_lblk_found) { + rc->first_do_lblk = i; + rc->first_do_lblk_found = true; + } + + /* update the last lblk in the region seen so far */ + rc->last_do_lblk = end; + + /* + * if we're tracking a partial cluster and the current extent + * doesn't start with it, count it and stop tracking + */ + if (rc->partial && (rc->lclu != EXT4_B2C(sbi, i))) { + rc->ndelonly++; + rc->partial = false; + } + + /* + * if the first cluster doesn't start on a cluster boundary but + * ends on one, count it + */ + if (EXT4_LBLK_COFF(sbi, i) != 0) { + if (end >= EXT4_LBLK_CFILL(sbi, i)) { + rc->ndelonly++; + rc->partial = false; + i = EXT4_LBLK_CFILL(sbi, i) + 1; + } + } + + /* + * if the current cluster starts on a cluster boundary, count the + * number of whole delonly clusters in the extent + */ + if ((i + sbi->s_cluster_ratio - 1) <= end) { + nclu = (end - i + 1) >> sbi->s_cluster_bits; + rc->ndelonly += nclu; + i += nclu << sbi->s_cluster_bits; + } + + /* + * start tracking a partial cluster if there's a partial at the end + * of the current extent and we're not already tracking one + */ + if (!rc->partial && i <= end) { + rc->partial = true; + rc->lclu = EXT4_B2C(sbi, i); + } +} + +/* + * __pr_tree_search - search for a pending cluster reservation + * + * @root - root of pending reservation tree + * @lclu - logical cluster to search for + * + * Returns the pending reservation for the cluster identified by @lclu + * if found. If not, returns a reservation for the next cluster if any, + * and if not, returns NULL. + */ +static struct pending_reservation *__pr_tree_search(struct rb_root *root, + ext4_lblk_t lclu) +{ + struct rb_node *node = root->rb_node; + struct pending_reservation *pr = NULL; + + while (node) { + pr = rb_entry(node, struct pending_reservation, rb_node); + if (lclu < pr->lclu) + node = node->rb_left; + else if (lclu > pr->lclu) + node = node->rb_right; + else + return pr; + } + if (pr && lclu < pr->lclu) + return pr; + if (pr && lclu > pr->lclu) { + node = rb_next(&pr->rb_node); + return node ? rb_entry(node, struct pending_reservation, + rb_node) : NULL; + } + return NULL; +} + +/* + * get_rsvd - calculates and returns the number of cluster reservations to be + * released when removing a block range from the extent status tree + * and releases any pending reservations within the range + * + * @inode - file containing block range + * @end - last block in range + * @right_es - pointer to extent containing next block beyond end or NULL + * @rc - pointer to reserved count data + * + * The number of reservations to be released is equal to the number of + * clusters containing delayed and not unwritten (delonly) blocks within + * the range, minus the number of clusters still containing delonly blocks + * at the ends of the range, and minus the number of pending reservations + * within the range. + */ +static unsigned int get_rsvd(struct inode *inode, ext4_lblk_t end, + struct extent_status *right_es, + struct rsvd_count *rc) +{ + struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); + struct pending_reservation *pr; + struct ext4_pending_tree *tree = &EXT4_I(inode)->i_pending_tree; + struct rb_node *node; + ext4_lblk_t first_lclu, last_lclu; + bool left_delonly, right_delonly, count_pending; + struct extent_status *es; + + if (sbi->s_cluster_ratio > 1) { + /* count any remaining partial cluster */ + if (rc->partial) + rc->ndelonly++; + + if (rc->ndelonly == 0) + return 0; + + first_lclu = EXT4_B2C(sbi, rc->first_do_lblk); + last_lclu = EXT4_B2C(sbi, rc->last_do_lblk); + + /* + * decrease the delonly count by the number of clusters at the + * ends of the range that still contain delonly blocks - + * these clusters still need to be reserved + */ + left_delonly = right_delonly = false; + + es = rc->left_es; + while (es && ext4_es_end(es) >= + EXT4_LBLK_CMASK(sbi, rc->first_do_lblk)) { + if (ext4_es_is_delonly(es)) { + rc->ndelonly--; + left_delonly = true; + break; + } + node = rb_prev(&es->rb_node); + if (!node) + break; + es = rb_entry(node, struct extent_status, rb_node); + } + if (right_es && (!left_delonly || first_lclu != last_lclu)) { + if (end < ext4_es_end(right_es)) { + es = right_es; + } else { + node = rb_next(&right_es->rb_node); + es = node ? rb_entry(node, struct extent_status, + rb_node) : NULL; + } + while (es && es->es_lblk <= + EXT4_LBLK_CFILL(sbi, rc->last_do_lblk)) { + if (ext4_es_is_delonly(es)) { + rc->ndelonly--; + right_delonly = true; + break; + } + node = rb_next(&es->rb_node); + if (!node) + break; + es = rb_entry(node, struct extent_status, + rb_node); + } + } + + /* + * Determine the block range that should be searched for + * pending reservations, if any. Clusters on the ends of the + * original removed range containing delonly blocks are + * excluded. They've already been accounted for and it's not + * possible to determine if an associated pending reservation + * should be released with the information available in the + * extents status tree. + */ + if (first_lclu == last_lclu) { + if (left_delonly | right_delonly) + count_pending = false; + else + count_pending = true; + } else { + if (left_delonly) + first_lclu++; + if (right_delonly) + last_lclu--; + if (first_lclu <= last_lclu) + count_pending = true; + else + count_pending = false; + } + + /* + * a pending reservation found between first_lclu and last_lclu + * represents an allocated cluster that contained at least one + * delonly block, so the delonly total must be reduced by one + * for each pending reservation found and released + */ + if (count_pending) { + pr = __pr_tree_search(&tree->root, first_lclu); + while (pr && pr->lclu <= last_lclu) { + rc->ndelonly--; + node = rb_next(&pr->rb_node); + rb_erase(&pr->rb_node, &tree->root); + __free_pending(pr); + if (!node) + break; + pr = rb_entry(node, struct pending_reservation, + rb_node); + } + } + } + return rc->ndelonly; +} + + +/* + * __es_remove_extent - removes block range from extent status tree + * + * @inode - file containing range + * @lblk - first block in range + * @end - last block in range + * @reserved - number of cluster reservations released + * @prealloc - pre-allocated es to avoid memory allocation failures + * + * If @reserved is not NULL and delayed allocation is enabled, counts + * block/cluster reservations freed by removing range and if bigalloc + * enabled cancels pending reservations as needed. Returns 0 on success, + * error code on failure. + */ +static int __es_remove_extent(struct inode *inode, ext4_lblk_t lblk, + ext4_lblk_t end, int *reserved, + struct extent_status *prealloc) +{ + 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; + ext4_fsblk_t block; + int err = 0; + bool count_reserved = true; + struct rsvd_count rc; + + if (reserved == NULL || !test_opt(inode->i_sb, DELALLOC)) + count_reserved = false; + + es = __es_tree_search(&tree->root, lblk); + if (!es) + goto out; + if (es->es_lblk > end) + goto out; + + /* Simply invalidate cache_es. */ + tree->cache_es = NULL; + if (count_reserved) + init_rsvd(inode, lblk, es, &rc); + + 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->es_len = len1; + if (len2 > 0) { + if (len1 > 0) { + struct extent_status newes; + + newes.es_lblk = end + 1; + newes.es_len = len2; + block = 0x7FDEADBEEFULL; + 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_status(&newes, block, + ext4_es_status(&orig_es)); + err = __es_insert_extent(inode, &newes, prealloc); + if (err) { + if (!ext4_es_must_keep(&newes)) + return 0; + + es->es_lblk = orig_es.es_lblk; + es->es_len = orig_es.es_len; + goto out; + } + } else { + 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); + } + } + if (count_reserved) + count_rsvd(inode, orig_es.es_lblk + len1, + orig_es.es_len - len1 - len2, &orig_es, &rc); + goto out_get_reserved; + } + + if (len1 > 0) { + if (count_reserved) + count_rsvd(inode, lblk, orig_es.es_len - len1, + &orig_es, &rc); + node = rb_next(&es->rb_node); + if (node) + es = rb_entry(node, struct extent_status, rb_node); + else + es = NULL; + } + + while (es && ext4_es_end(es) <= end) { + if (count_reserved) + count_rsvd(inode, es->es_lblk, es->es_len, es, &rc); + node = rb_next(&es->rb_node); + rb_erase(&es->rb_node, &tree->root); + ext4_es_free_extent(inode, es); + if (!node) { + es = NULL; + break; + } + es = rb_entry(node, struct extent_status, rb_node); + } + + if (es && es->es_lblk < end + 1) { + ext4_lblk_t orig_len = es->es_len; + + len1 = ext4_es_end(es) - end; + if (count_reserved) + count_rsvd(inode, es->es_lblk, orig_len - len1, + es, &rc); + 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_get_reserved: + if (count_reserved) + *reserved = get_rsvd(inode, end, es, &rc); +out: + return err; +} + +/* + * ext4_es_remove_extent - removes block range from extent status tree + * + * @inode - file containing range + * @lblk - first block in range + * @len - number of blocks to remove + * + * Reduces block/cluster reservation count and for bigalloc cancels pending + * reservations as needed. + */ +void ext4_es_remove_extent(struct inode *inode, ext4_lblk_t lblk, + ext4_lblk_t len) +{ + ext4_lblk_t end; + int err = 0; + int reserved = 0; + struct extent_status *es = NULL; + + if (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY) + return; + + 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; + + end = lblk + len - 1; + BUG_ON(end < lblk); + +retry: + if (err && !es) + es = __es_alloc_extent(true); + /* + * ext4_clear_inode() depends on us taking i_es_lock unconditionally + * so that we are sure __es_shrink() is done with the inode before it + * is reclaimed. + */ + write_lock(&EXT4_I(inode)->i_es_lock); + err = __es_remove_extent(inode, lblk, end, &reserved, es); + /* Free preallocated extent if it didn't get used. */ + if (es) { + if (!es->es_len) + __es_free_extent(es); + es = NULL; + } + write_unlock(&EXT4_I(inode)->i_es_lock); + if (err) + goto retry; + + ext4_es_print_tree(inode); + ext4_da_release_space(inode, reserved); + return; +} + +static int __es_shrink(struct ext4_sb_info *sbi, int nr_to_scan, + struct ext4_inode_info *locked_ei) +{ + struct ext4_inode_info *ei; + struct ext4_es_stats *es_stats; + ktime_t start_time; + u64 scan_time; + int nr_to_walk; + int nr_shrunk = 0; + int retried = 0, nr_skipped = 0; + + es_stats = &sbi->s_es_stats; + start_time = ktime_get(); + +retry: + spin_lock(&sbi->s_es_lock); + nr_to_walk = sbi->s_es_nr_inode; + while (nr_to_walk-- > 0) { + if (list_empty(&sbi->s_es_list)) { + spin_unlock(&sbi->s_es_lock); + goto out; + } + ei = list_first_entry(&sbi->s_es_list, struct ext4_inode_info, + i_es_list); + /* Move the inode to the tail */ + list_move_tail(&ei->i_es_list, &sbi->s_es_list); + + /* + * Normally we try hard to avoid shrinking precached inodes, + * but we will as a last resort. + */ + if (!retried && ext4_test_inode_state(&ei->vfs_inode, + EXT4_STATE_EXT_PRECACHED)) { + nr_skipped++; + continue; + } + + if (ei == locked_ei || !write_trylock(&ei->i_es_lock)) { + nr_skipped++; + continue; + } + /* + * Now we hold i_es_lock which protects us from inode reclaim + * freeing inode under us + */ + spin_unlock(&sbi->s_es_lock); + + nr_shrunk += es_reclaim_extents(ei, &nr_to_scan); + write_unlock(&ei->i_es_lock); + + if (nr_to_scan <= 0) + goto out; + spin_lock(&sbi->s_es_lock); + } + spin_unlock(&sbi->s_es_lock); + + /* + * If we skipped any inodes, and we weren't able to make any + * forward progress, try again to scan precached inodes. + */ + if ((nr_shrunk == 0) && nr_skipped && !retried) { + retried++; + goto retry; + } + + if (locked_ei && nr_shrunk == 0) + nr_shrunk = es_reclaim_extents(locked_ei, &nr_to_scan); + +out: + scan_time = ktime_to_ns(ktime_sub(ktime_get(), start_time)); + if (likely(es_stats->es_stats_scan_time)) + es_stats->es_stats_scan_time = (scan_time + + es_stats->es_stats_scan_time*3) / 4; + else + es_stats->es_stats_scan_time = scan_time; + if (scan_time > es_stats->es_stats_max_scan_time) + es_stats->es_stats_max_scan_time = scan_time; + if (likely(es_stats->es_stats_shrunk)) + es_stats->es_stats_shrunk = (nr_shrunk + + es_stats->es_stats_shrunk*3) / 4; + else + es_stats->es_stats_shrunk = nr_shrunk; + + trace_ext4_es_shrink(sbi->s_sb, nr_shrunk, scan_time, + nr_skipped, retried); + return nr_shrunk; +} + +static unsigned long ext4_es_count(struct shrinker *shrink, + struct shrink_control *sc) +{ + unsigned long nr; + struct ext4_sb_info *sbi; + + sbi = container_of(shrink, struct ext4_sb_info, s_es_shrinker); + nr = percpu_counter_read_positive(&sbi->s_es_stats.es_stats_shk_cnt); + trace_ext4_es_shrink_count(sbi->s_sb, sc->nr_to_scan, nr); + return nr; +} + +static unsigned long ext4_es_scan(struct shrinker *shrink, + struct shrink_control *sc) +{ + struct ext4_sb_info *sbi = container_of(shrink, + struct ext4_sb_info, s_es_shrinker); + int nr_to_scan = sc->nr_to_scan; + int ret, nr_shrunk; + + ret = percpu_counter_read_positive(&sbi->s_es_stats.es_stats_shk_cnt); + trace_ext4_es_shrink_scan_enter(sbi->s_sb, nr_to_scan, ret); + + nr_shrunk = __es_shrink(sbi, nr_to_scan, NULL); + + ret = percpu_counter_read_positive(&sbi->s_es_stats.es_stats_shk_cnt); + trace_ext4_es_shrink_scan_exit(sbi->s_sb, nr_shrunk, ret); + return nr_shrunk; +} + +int ext4_seq_es_shrinker_info_show(struct seq_file *seq, void *v) +{ + struct ext4_sb_info *sbi = EXT4_SB((struct super_block *) seq->private); + struct ext4_es_stats *es_stats = &sbi->s_es_stats; + struct ext4_inode_info *ei, *max = NULL; + unsigned int inode_cnt = 0; + + if (v != SEQ_START_TOKEN) + return 0; + + /* here we just find an inode that has the max nr. of objects */ + spin_lock(&sbi->s_es_lock); + list_for_each_entry(ei, &sbi->s_es_list, i_es_list) { + inode_cnt++; + if (max && max->i_es_all_nr < ei->i_es_all_nr) + max = ei; + else if (!max) + max = ei; + } + spin_unlock(&sbi->s_es_lock); + + seq_printf(seq, "stats:\n %lld objects\n %lld reclaimable objects\n", + percpu_counter_sum_positive(&es_stats->es_stats_all_cnt), + percpu_counter_sum_positive(&es_stats->es_stats_shk_cnt)); + seq_printf(seq, " %lld/%lld cache hits/misses\n", + percpu_counter_sum_positive(&es_stats->es_stats_cache_hits), + percpu_counter_sum_positive(&es_stats->es_stats_cache_misses)); + if (inode_cnt) + seq_printf(seq, " %d inodes on list\n", inode_cnt); + + seq_printf(seq, "average:\n %llu us scan time\n", + div_u64(es_stats->es_stats_scan_time, 1000)); + seq_printf(seq, " %lu shrunk objects\n", es_stats->es_stats_shrunk); + if (inode_cnt) + seq_printf(seq, + "maximum:\n %lu inode (%u objects, %u reclaimable)\n" + " %llu us max scan time\n", + max->vfs_inode.i_ino, max->i_es_all_nr, max->i_es_shk_nr, + div_u64(es_stats->es_stats_max_scan_time, 1000)); + + return 0; +} + +int ext4_es_register_shrinker(struct ext4_sb_info *sbi) +{ + int err; + + /* Make sure we have enough bits for physical block number */ + BUILD_BUG_ON(ES_SHIFT < 48); + INIT_LIST_HEAD(&sbi->s_es_list); + sbi->s_es_nr_inode = 0; + spin_lock_init(&sbi->s_es_lock); + sbi->s_es_stats.es_stats_shrunk = 0; + err = percpu_counter_init(&sbi->s_es_stats.es_stats_cache_hits, 0, + GFP_KERNEL); + if (err) + return err; + err = percpu_counter_init(&sbi->s_es_stats.es_stats_cache_misses, 0, + GFP_KERNEL); + if (err) + goto err1; + sbi->s_es_stats.es_stats_scan_time = 0; + sbi->s_es_stats.es_stats_max_scan_time = 0; + err = percpu_counter_init(&sbi->s_es_stats.es_stats_all_cnt, 0, GFP_KERNEL); + if (err) + goto err2; + err = percpu_counter_init(&sbi->s_es_stats.es_stats_shk_cnt, 0, GFP_KERNEL); + if (err) + goto err3; + + sbi->s_es_shrinker.scan_objects = ext4_es_scan; + sbi->s_es_shrinker.count_objects = ext4_es_count; + sbi->s_es_shrinker.seeks = DEFAULT_SEEKS; + err = register_shrinker(&sbi->s_es_shrinker, "ext4-es:%s", + sbi->s_sb->s_id); + if (err) + goto err4; + + return 0; +err4: + percpu_counter_destroy(&sbi->s_es_stats.es_stats_shk_cnt); +err3: + percpu_counter_destroy(&sbi->s_es_stats.es_stats_all_cnt); +err2: + percpu_counter_destroy(&sbi->s_es_stats.es_stats_cache_misses); +err1: + percpu_counter_destroy(&sbi->s_es_stats.es_stats_cache_hits); + return err; +} + +void ext4_es_unregister_shrinker(struct ext4_sb_info *sbi) +{ + percpu_counter_destroy(&sbi->s_es_stats.es_stats_cache_hits); + percpu_counter_destroy(&sbi->s_es_stats.es_stats_cache_misses); + percpu_counter_destroy(&sbi->s_es_stats.es_stats_all_cnt); + percpu_counter_destroy(&sbi->s_es_stats.es_stats_shk_cnt); + unregister_shrinker(&sbi->s_es_shrinker); +} + +/* + * Shrink extents in given inode from ei->i_es_shrink_lblk till end. Scan at + * most *nr_to_scan extents, update *nr_to_scan accordingly. + * + * Return 0 if we hit end of tree / interval, 1 if we exhausted nr_to_scan. + * Increment *nr_shrunk by the number of reclaimed extents. Also update + * ei->i_es_shrink_lblk to where we should continue scanning. + */ +static int es_do_reclaim_extents(struct ext4_inode_info *ei, ext4_lblk_t end, + int *nr_to_scan, int *nr_shrunk) +{ + struct inode *inode = &ei->vfs_inode; + struct ext4_es_tree *tree = &ei->i_es_tree; + struct extent_status *es; + struct rb_node *node; + + es = __es_tree_search(&tree->root, ei->i_es_shrink_lblk); + if (!es) + goto out_wrap; + + while (*nr_to_scan > 0) { + if (es->es_lblk > end) { + ei->i_es_shrink_lblk = end + 1; + return 0; + } + + (*nr_to_scan)--; + node = rb_next(&es->rb_node); + + if (ext4_es_must_keep(es)) + goto next; + if (ext4_es_is_referenced(es)) { + ext4_es_clear_referenced(es); + goto next; + } + + rb_erase(&es->rb_node, &tree->root); + ext4_es_free_extent(inode, es); + (*nr_shrunk)++; +next: + if (!node) + goto out_wrap; + es = rb_entry(node, struct extent_status, rb_node); + } + ei->i_es_shrink_lblk = es->es_lblk; + return 1; +out_wrap: + ei->i_es_shrink_lblk = 0; + return 0; +} + +static int es_reclaim_extents(struct ext4_inode_info *ei, int *nr_to_scan) +{ + struct inode *inode = &ei->vfs_inode; + int nr_shrunk = 0; + ext4_lblk_t start = ei->i_es_shrink_lblk; + static DEFINE_RATELIMIT_STATE(_rs, DEFAULT_RATELIMIT_INTERVAL, + DEFAULT_RATELIMIT_BURST); + + if (ei->i_es_shk_nr == 0) + return 0; + + if (ext4_test_inode_state(inode, EXT4_STATE_EXT_PRECACHED) && + __ratelimit(&_rs)) + ext4_warning(inode->i_sb, "forced shrink of precached extents"); + + if (!es_do_reclaim_extents(ei, EXT_MAX_BLOCKS, nr_to_scan, &nr_shrunk) && + start != 0) + es_do_reclaim_extents(ei, start - 1, nr_to_scan, &nr_shrunk); + + ei->i_es_tree.cache_es = NULL; + return nr_shrunk; +} + +/* + * Called to support EXT4_IOC_CLEAR_ES_CACHE. We can only remove + * discretionary entries from the extent status cache. (Some entries + * must be present for proper operations.) + */ +void ext4_clear_inode_es(struct inode *inode) +{ + struct ext4_inode_info *ei = EXT4_I(inode); + struct extent_status *es; + struct ext4_es_tree *tree; + struct rb_node *node; + + write_lock(&ei->i_es_lock); + tree = &EXT4_I(inode)->i_es_tree; + tree->cache_es = NULL; + node = rb_first(&tree->root); + while (node) { + es = rb_entry(node, struct extent_status, rb_node); + node = rb_next(node); + if (!ext4_es_must_keep(es)) { + rb_erase(&es->rb_node, &tree->root); + ext4_es_free_extent(inode, es); + } + } + ext4_clear_inode_state(inode, EXT4_STATE_EXT_PRECACHED); + write_unlock(&ei->i_es_lock); +} + +#ifdef ES_DEBUG__ +static void ext4_print_pending_tree(struct inode *inode) +{ + struct ext4_pending_tree *tree; + struct rb_node *node; + struct pending_reservation *pr; + + printk(KERN_DEBUG "pending reservations for inode %lu:", inode->i_ino); + tree = &EXT4_I(inode)->i_pending_tree; + node = rb_first(&tree->root); + while (node) { + pr = rb_entry(node, struct pending_reservation, rb_node); + printk(KERN_DEBUG " %u", pr->lclu); + node = rb_next(node); + } + printk(KERN_DEBUG "\n"); +} +#else +#define ext4_print_pending_tree(inode) +#endif + +int __init ext4_init_pending(void) +{ + ext4_pending_cachep = KMEM_CACHE(pending_reservation, SLAB_RECLAIM_ACCOUNT); + if (ext4_pending_cachep == NULL) + return -ENOMEM; + return 0; +} + +void ext4_exit_pending(void) +{ + kmem_cache_destroy(ext4_pending_cachep); +} + +void ext4_init_pending_tree(struct ext4_pending_tree *tree) +{ + tree->root = RB_ROOT; +} + +/* + * __get_pending - retrieve a pointer to a pending reservation + * + * @inode - file containing the pending cluster reservation + * @lclu - logical cluster of interest + * + * Returns a pointer to a pending reservation if it's a member of + * the set, and NULL if not. Must be called holding i_es_lock. + */ +static struct pending_reservation *__get_pending(struct inode *inode, + ext4_lblk_t lclu) +{ + struct ext4_pending_tree *tree; + struct rb_node *node; + struct pending_reservation *pr = NULL; + + tree = &EXT4_I(inode)->i_pending_tree; + node = (&tree->root)->rb_node; + + while (node) { + pr = rb_entry(node, struct pending_reservation, rb_node); + if (lclu < pr->lclu) + node = node->rb_left; + else if (lclu > pr->lclu) + node = node->rb_right; + else if (lclu == pr->lclu) + return pr; + } + return NULL; +} + +/* + * __insert_pending - adds a pending cluster reservation to the set of + * pending reservations + * + * @inode - file containing the cluster + * @lblk - logical block in the cluster to be added + * @prealloc - preallocated pending entry + * + * Returns 0 on successful insertion and -ENOMEM on failure. If the + * pending reservation is already in the set, returns successfully. + */ +static int __insert_pending(struct inode *inode, ext4_lblk_t lblk, + struct pending_reservation **prealloc) +{ + struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); + struct ext4_pending_tree *tree = &EXT4_I(inode)->i_pending_tree; + struct rb_node **p = &tree->root.rb_node; + struct rb_node *parent = NULL; + struct pending_reservation *pr; + ext4_lblk_t lclu; + int ret = 0; + + lclu = EXT4_B2C(sbi, lblk); + /* search to find parent for insertion */ + while (*p) { + parent = *p; + pr = rb_entry(parent, struct pending_reservation, rb_node); + + if (lclu < pr->lclu) { + p = &(*p)->rb_left; + } else if (lclu > pr->lclu) { + p = &(*p)->rb_right; + } else { + /* pending reservation already inserted */ + goto out; + } + } + + if (likely(*prealloc == NULL)) { + pr = __alloc_pending(false); + if (!pr) { + ret = -ENOMEM; + goto out; + } + } else { + pr = *prealloc; + *prealloc = NULL; + } + pr->lclu = lclu; + + rb_link_node(&pr->rb_node, parent, p); + rb_insert_color(&pr->rb_node, &tree->root); + +out: + return ret; +} + +/* + * __remove_pending - removes a pending cluster reservation from the set + * of pending reservations + * + * @inode - file containing the cluster + * @lblk - logical block in the pending cluster reservation to be removed + * + * Returns successfully if pending reservation is not a member of the set. + */ +static void __remove_pending(struct inode *inode, ext4_lblk_t lblk) +{ + struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); + struct pending_reservation *pr; + struct ext4_pending_tree *tree; + + pr = __get_pending(inode, EXT4_B2C(sbi, lblk)); + if (pr != NULL) { + tree = &EXT4_I(inode)->i_pending_tree; + rb_erase(&pr->rb_node, &tree->root); + __free_pending(pr); + } +} + +/* + * ext4_remove_pending - removes a pending cluster reservation from the set + * of pending reservations + * + * @inode - file containing the cluster + * @lblk - logical block in the pending cluster reservation to be removed + * + * Locking for external use of __remove_pending. + */ +void ext4_remove_pending(struct inode *inode, ext4_lblk_t lblk) +{ + struct ext4_inode_info *ei = EXT4_I(inode); + + write_lock(&ei->i_es_lock); + __remove_pending(inode, lblk); + write_unlock(&ei->i_es_lock); +} + +/* + * ext4_is_pending - determine whether a cluster has a pending reservation + * on it + * + * @inode - file containing the cluster + * @lblk - logical block in the cluster + * + * Returns true if there's a pending reservation for the cluster in the + * set of pending reservations, and false if not. + */ +bool ext4_is_pending(struct inode *inode, ext4_lblk_t lblk) +{ + struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); + struct ext4_inode_info *ei = EXT4_I(inode); + bool ret; + + read_lock(&ei->i_es_lock); + ret = (bool)(__get_pending(inode, EXT4_B2C(sbi, lblk)) != NULL); + read_unlock(&ei->i_es_lock); + + return ret; +} + +/* + * ext4_es_insert_delayed_block - adds a delayed block to the extents status + * tree, adding a pending reservation where + * needed + * + * @inode - file containing the newly added block + * @lblk - logical block to be added + * @allocated - indicates whether a physical cluster has been allocated for + * the logical cluster that contains the block + */ +void ext4_es_insert_delayed_block(struct inode *inode, ext4_lblk_t lblk, + bool allocated) +{ + struct extent_status newes; + int err1 = 0, err2 = 0, err3 = 0; + struct extent_status *es1 = NULL; + struct extent_status *es2 = NULL; + struct pending_reservation *pr = NULL; + + if (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY) + return; + + es_debug("add [%u/1) delayed to extent status tree of inode %lu\n", + lblk, inode->i_ino); + + newes.es_lblk = lblk; + newes.es_len = 1; + ext4_es_store_pblock_status(&newes, ~0, EXTENT_STATUS_DELAYED); + trace_ext4_es_insert_delayed_block(inode, &newes, allocated); + + ext4_es_insert_extent_check(inode, &newes); + +retry: + if (err1 && !es1) + es1 = __es_alloc_extent(true); + if ((err1 || err2) && !es2) + es2 = __es_alloc_extent(true); + if ((err1 || err2 || err3) && allocated && !pr) + pr = __alloc_pending(true); + write_lock(&EXT4_I(inode)->i_es_lock); + + err1 = __es_remove_extent(inode, lblk, lblk, NULL, es1); + if (err1 != 0) + goto error; + /* Free preallocated extent if it didn't get used. */ + if (es1) { + if (!es1->es_len) + __es_free_extent(es1); + es1 = NULL; + } + + err2 = __es_insert_extent(inode, &newes, es2); + if (err2 != 0) + goto error; + /* Free preallocated extent if it didn't get used. */ + if (es2) { + if (!es2->es_len) + __es_free_extent(es2); + es2 = NULL; + } + + if (allocated) { + err3 = __insert_pending(inode, lblk, &pr); + if (err3 != 0) + goto error; + if (pr) { + __free_pending(pr); + pr = NULL; + } + } +error: + write_unlock(&EXT4_I(inode)->i_es_lock); + if (err1 || err2 || err3) + goto retry; + + ext4_es_print_tree(inode); + ext4_print_pending_tree(inode); + return; +} + +/* + * __es_delayed_clu - count number of clusters containing blocks that + * are delayed only + * + * @inode - file containing block range + * @start - logical block defining start of range + * @end - logical block defining end of range + * + * Returns the number of clusters containing only delayed (not delayed + * and unwritten) blocks in the range specified by @start and @end. Any + * cluster or part of a cluster within the range and containing a delayed + * and not unwritten block within the range is counted as a whole cluster. + */ +static unsigned int __es_delayed_clu(struct inode *inode, ext4_lblk_t start, + ext4_lblk_t end) +{ + struct ext4_es_tree *tree = &EXT4_I(inode)->i_es_tree; + struct extent_status *es; + struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); + struct rb_node *node; + ext4_lblk_t first_lclu, last_lclu; + unsigned long long last_counted_lclu; + unsigned int n = 0; + + /* guaranteed to be unequal to any ext4_lblk_t value */ + last_counted_lclu = ~0ULL; + + es = __es_tree_search(&tree->root, start); + + while (es && (es->es_lblk <= end)) { + if (ext4_es_is_delonly(es)) { + if (es->es_lblk <= start) + first_lclu = EXT4_B2C(sbi, start); + else + first_lclu = EXT4_B2C(sbi, es->es_lblk); + + if (ext4_es_end(es) >= end) + last_lclu = EXT4_B2C(sbi, end); + else + last_lclu = EXT4_B2C(sbi, ext4_es_end(es)); + + if (first_lclu == last_counted_lclu) + n += last_lclu - first_lclu; + else + n += last_lclu - first_lclu + 1; + last_counted_lclu = last_lclu; + } + node = rb_next(&es->rb_node); + if (!node) + break; + es = rb_entry(node, struct extent_status, rb_node); + } + + return n; +} + +/* + * ext4_es_delayed_clu - count number of clusters containing blocks that + * are both delayed and unwritten + * + * @inode - file containing block range + * @lblk - logical block defining start of range + * @len - number of blocks in range + * + * Locking for external use of __es_delayed_clu(). + */ +unsigned int ext4_es_delayed_clu(struct inode *inode, ext4_lblk_t lblk, + ext4_lblk_t len) +{ + struct ext4_inode_info *ei = EXT4_I(inode); + ext4_lblk_t end; + unsigned int n; + + if (len == 0) + return 0; + + end = lblk + len - 1; + WARN_ON(end < lblk); + + read_lock(&ei->i_es_lock); + + n = __es_delayed_clu(inode, lblk, end); + + read_unlock(&ei->i_es_lock); + + return n; +} + +/* + * __revise_pending - makes, cancels, or leaves unchanged pending cluster + * reservations for a specified block range depending + * upon the presence or absence of delayed blocks + * outside the range within clusters at the ends of the + * range + * + * @inode - file containing the range + * @lblk - logical block defining the start of range + * @len - length of range in blocks + * @prealloc - preallocated pending entry + * + * Used after a newly allocated extent is added to the extents status tree. + * Requires that the extents in the range have either written or unwritten + * status. Must be called while holding i_es_lock. + */ +static int __revise_pending(struct inode *inode, ext4_lblk_t lblk, + ext4_lblk_t len, + struct pending_reservation **prealloc) +{ + struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); + ext4_lblk_t end = lblk + len - 1; + ext4_lblk_t first, last; + bool f_del = false, l_del = false; + int ret = 0; + + if (len == 0) + return 0; + + /* + * Two cases - block range within single cluster and block range + * spanning two or more clusters. Note that a cluster belonging + * to a range starting and/or ending on a cluster boundary is treated + * as if it does not contain a delayed extent. The new range may + * have allocated space for previously delayed blocks out to the + * cluster boundary, requiring that any pre-existing pending + * reservation be canceled. Because this code only looks at blocks + * outside the range, it should revise pending reservations + * correctly even if the extent represented by the range can't be + * inserted in the extents status tree due to ENOSPC. + */ + + if (EXT4_B2C(sbi, lblk) == EXT4_B2C(sbi, end)) { + first = EXT4_LBLK_CMASK(sbi, lblk); + if (first != lblk) + f_del = __es_scan_range(inode, &ext4_es_is_delonly, + first, lblk - 1); + if (f_del) { + ret = __insert_pending(inode, first, prealloc); + if (ret < 0) + goto out; + } else { + last = EXT4_LBLK_CMASK(sbi, end) + + sbi->s_cluster_ratio - 1; + if (last != end) + l_del = __es_scan_range(inode, + &ext4_es_is_delonly, + end + 1, last); + if (l_del) { + ret = __insert_pending(inode, last, prealloc); + if (ret < 0) + goto out; + } else + __remove_pending(inode, last); + } + } else { + first = EXT4_LBLK_CMASK(sbi, lblk); + if (first != lblk) + f_del = __es_scan_range(inode, &ext4_es_is_delonly, + first, lblk - 1); + if (f_del) { + ret = __insert_pending(inode, first, prealloc); + if (ret < 0) + goto out; + } else + __remove_pending(inode, first); + + last = EXT4_LBLK_CMASK(sbi, end) + sbi->s_cluster_ratio - 1; + if (last != end) + l_del = __es_scan_range(inode, &ext4_es_is_delonly, + end + 1, last); + if (l_del) { + ret = __insert_pending(inode, last, prealloc); + if (ret < 0) + goto out; + } else + __remove_pending(inode, last); + } +out: + return ret; +} |