fs/ext4/extents

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This source file includes following definitions.
ext4_init_es
ext4_exit_es
ext4_es_init_tree
ext4_es_print_tree
ext4_es_end
__es_tree_search
__es_find_extent_range
ext4_es_find_extent_range
__es_scan_range
ext4_es_scan_range
__es_scan_clu
ext4_es_scan_clu
ext4_es_list_add
ext4_es_list_del
ext4_es_alloc_extent
ext4_es_free_extent
ext4_es_can_be_merged
ext4_es_try_to_merge_left
ext4_es_try_to_merge_right
ext4_es_insert_extent_ext_check
ext4_es_insert_extent_ind_check
ext4_es_insert_extent_check
ext4_es_insert_extent_check
__es_insert_extent
ext4_es_insert_extent
ext4_es_cache_extent
ext4_es_lookup_extent
init_rsvd
count_rsvd
__pr_tree_search
get_rsvd
__es_remove_extent
ext4_es_remove_extent
__es_shrink
ext4_es_count
ext4_es_scan
ext4_seq_es_shrinker_info_show
ext4_es_register_shrinker
ext4_es_unregister_shrinker
es_do_reclaim_extents
es_reclaim_extents
ext4_clear_inode_es
ext4_print_pending_tree
ext4_init_pending
ext4_exit_pending
ext4_init_pending_tree
__get_pending
__insert_pending
__remove_pending
ext4_remove_pending
ext4_is_pending
ext4_es_insert_delayed_block
__es_delayed_clu
ext4_es_delayed_clu
__revise_pending
   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  fs/ext4/extents_status.c
   4  *
   5  * Written by Yongqiang Yang <xiaoqiangnk@gmail.com>
   6  * Modified by
   7  *      Allison Henderson <achender@linux.vnet.ibm.com>
   8  *      Hugh Dickins <hughd@google.com>
   9  *      Zheng Liu <wenqing.lz@taobao.com>
  10  *
  11  * Ext4 extents status tree core functions.
  12  */
  13 #include <linux/list_sort.h>
  14 #include <linux/proc_fs.h>
  15 #include <linux/seq_file.h>
  16 #include "ext4.h"
  17 
  18 #include <trace/events/ext4.h>
  19 
  20 /*
  21  * According to previous discussion in Ext4 Developer Workshop, we
  22  * will introduce a new structure called io tree to track all extent
  23  * status in order to solve some problems that we have met
  24  * (e.g. Reservation space warning), and provide extent-level locking.
  25  * Delay extent tree is the first step to achieve this goal.  It is
  26  * original built by Yongqiang Yang.  At that time it is called delay
  27  * extent tree, whose goal is only track delayed extents in memory to
  28  * simplify the implementation of fiemap and bigalloc, and introduce
  29  * lseek SEEK_DATA/SEEK_HOLE support.  That is why it is still called
  30  * delay extent tree at the first commit.  But for better understand
  31  * what it does, it has been rename to extent status tree.
  32  *
  33  * Step1:
  34  * Currently the first step has been done.  All delayed extents are
  35  * tracked in the tree.  It maintains the delayed extent when a delayed
  36  * allocation is issued, and the delayed extent is written out or
  37  * invalidated.  Therefore the implementation of fiemap and bigalloc
  38  * are simplified, and SEEK_DATA/SEEK_HOLE are introduced.
  39  *
  40  * The following comment describes the implemenmtation of extent
  41  * status tree and future works.
  42  *
  43  * Step2:
  44  * In this step all extent status are tracked by extent status tree.
  45  * Thus, we can first try to lookup a block mapping in this tree before
  46  * finding it in extent tree.  Hence, single extent cache can be removed
  47  * because extent status tree can do a better job.  Extents in status
  48  * tree are loaded on-demand.  Therefore, the extent status tree may not
  49  * contain all of the extents in a file.  Meanwhile we define a shrinker
  50  * to reclaim memory from extent status tree because fragmented extent
  51  * tree will make status tree cost too much memory.  written/unwritten/-
  52  * hole extents in the tree will be reclaimed by this shrinker when we
  53  * are under high memory pressure.  Delayed extents will not be
  54  * reclimed because fiemap, bigalloc, and seek_data/hole need it.
  55  */
  56 
  57 /*
  58  * Extent status tree implementation for ext4.
  59  *
  60  *
  61  * ==========================================================================
  62  * Extent status tree tracks all extent status.
  63  *
  64  * 1. Why we need to implement extent status tree?
  65  *
  66  * Without extent status tree, ext4 identifies a delayed extent by looking
  67  * up page cache, this has several deficiencies - complicated, buggy,
  68  * and inefficient code.
  69  *
  70  * FIEMAP, SEEK_HOLE/DATA, bigalloc, and writeout all need to know if a
  71  * block or a range of blocks are belonged to a delayed extent.
  72  *
  73  * Let us have a look at how they do without extent status tree.
  74  *   -- FIEMAP
  75  *      FIEMAP looks up page cache to identify delayed allocations from holes.
  76  *
  77  *   -- SEEK_HOLE/DATA
  78  *      SEEK_HOLE/DATA has the same problem as FIEMAP.
  79  *
  80  *   -- bigalloc
  81  *      bigalloc looks up page cache to figure out if a block is
  82  *      already under delayed allocation or not to determine whether
  83  *      quota reserving is needed for the cluster.
  84  *
  85  *   -- writeout
  86  *      Writeout looks up whole page cache to see if a buffer is
  87  *      mapped, If there are not very many delayed buffers, then it is
  88  *      time consuming.
  89  *
  90  * With extent status tree implementation, FIEMAP, SEEK_HOLE/DATA,
  91  * bigalloc and writeout can figure out if a block or a range of
  92  * blocks is under delayed allocation(belonged to a delayed extent) or
  93  * not by searching the extent tree.
  94  *
  95  *
  96  * ==========================================================================
  97  * 2. Ext4 extent status tree impelmentation
  98  *
  99  *   -- extent
 100  *      A extent is a range of blocks which are contiguous logically and
 101  *      physically.  Unlike extent in extent tree, this extent in ext4 is
 102  *      a in-memory struct, there is no corresponding on-disk data.  There
 103  *      is no limit on length of extent, so an extent can contain as many
 104  *      blocks as they are contiguous logically and physically.
 105  *
 106  *   -- extent status tree
 107  *      Every inode has an extent status tree and all allocation blocks
 108  *      are added to the tree with different status.  The extent in the
 109  *      tree are ordered by logical block no.
 110  *
 111  *   -- operations on a extent status tree
 112  *      There are three important operations on a delayed extent tree: find
 113  *      next extent, adding a extent(a range of blocks) and removing a extent.
 114  *
 115  *   -- race on a extent status tree
 116  *      Extent status tree is protected by inode->i_es_lock.
 117  *
 118  *   -- memory consumption
 119  *      Fragmented extent tree will make extent status tree cost too much
 120  *      memory.  Hence, we will reclaim written/unwritten/hole extents from
 121  *      the tree under a heavy memory pressure.
 122  *
 123  *
 124  * ==========================================================================
 125  * 3. Performance analysis
 126  *
 127  *   -- overhead
 128  *      1. There is a cache extent for write access, so if writes are
 129  *      not very random, adding space operaions are in O(1) time.
 130  *
 131  *   -- gain
 132  *      2. Code is much simpler, more readable, more maintainable and
 133  *      more efficient.
 134  *
 135  *
 136  * ==========================================================================
 137  * 4. TODO list
 138  *
 139  *   -- Refactor delayed space reservation
 140  *
 141  *   -- Extent-level locking
 142  */
 143 
 144 static struct kmem_cache *ext4_es_cachep;
 145 static struct kmem_cache *ext4_pending_cachep;
 146 
 147 static int __es_insert_extent(struct inode *inode, struct extent_status *newes);
 148 static int __es_remove_extent(struct inode *inode, ext4_lblk_t lblk,
 149                               ext4_lblk_t end, int *reserved);
 150 static int es_reclaim_extents(struct ext4_inode_info *ei, int *nr_to_scan);
 151 static int __es_shrink(struct ext4_sb_info *sbi, int nr_to_scan,
 152                        struct ext4_inode_info *locked_ei);
 153 static void __revise_pending(struct inode *inode, ext4_lblk_t lblk,
 154                              ext4_lblk_t len);
 155 
 156 int __init ext4_init_es(void)
 157 {
 158         ext4_es_cachep = kmem_cache_create("ext4_extent_status",
 159                                            sizeof(struct extent_status),
 160                                            0, (SLAB_RECLAIM_ACCOUNT), NULL);
 161         if (ext4_es_cachep == NULL)
 162                 return -ENOMEM;
 163         return 0;
 164 }
 165 
 166 void ext4_exit_es(void)
 167 {
 168         kmem_cache_destroy(ext4_es_cachep);
 169 }
 170 
 171 void ext4_es_init_tree(struct ext4_es_tree *tree)
 172 {
 173         tree->root = RB_ROOT;
 174         tree->cache_es = NULL;
 175 }
 176 
 177 #ifdef ES_DEBUG__
 178 static void ext4_es_print_tree(struct inode *inode)
 179 {
 180         struct ext4_es_tree *tree;
 181         struct rb_node *node;
 182 
 183         printk(KERN_DEBUG "status extents for inode %lu:", inode->i_ino);
 184         tree = &EXT4_I(inode)->i_es_tree;
 185         node = rb_first(&tree->root);
 186         while (node) {
 187                 struct extent_status *es;
 188                 es = rb_entry(node, struct extent_status, rb_node);
 189                 printk(KERN_DEBUG " [%u/%u) %llu %x",
 190                        es->es_lblk, es->es_len,
 191                        ext4_es_pblock(es), ext4_es_status(es));
 192                 node = rb_next(node);
 193         }
 194         printk(KERN_DEBUG "\n");
 195 }
 196 #else
 197 #define ext4_es_print_tree(inode)
 198 #endif
 199 
 200 static inline ext4_lblk_t ext4_es_end(struct extent_status *es)
 201 {
 202         BUG_ON(es->es_lblk + es->es_len < es->es_lblk);
 203         return es->es_lblk + es->es_len - 1;
 204 }
 205 
 206 /*
 207  * search through the tree for an delayed extent with a given offset.  If
 208  * it can't be found, try to find next extent.
 209  */
 210 static struct extent_status *__es_tree_search(struct rb_root *root,
 211                                               ext4_lblk_t lblk)
 212 {
 213         struct rb_node *node = root->rb_node;
 214         struct extent_status *es = NULL;
 215 
 216         while (node) {
 217                 es = rb_entry(node, struct extent_status, rb_node);
 218                 if (lblk < es->es_lblk)
 219                         node = node->rb_left;
 220                 else if (lblk > ext4_es_end(es))
 221                         node = node->rb_right;
 222                 else
 223                         return es;
 224         }
 225 
 226         if (es && lblk < es->es_lblk)
 227                 return es;
 228 
 229         if (es && lblk > ext4_es_end(es)) {
 230                 node = rb_next(&es->rb_node);
 231                 return node ? rb_entry(node, struct extent_status, rb_node) :
 232                               NULL;
 233         }
 234 
 235         return NULL;
 236 }
 237 
 238 /*
 239  * ext4_es_find_extent_range - find extent with specified status within block
 240  *                             range or next extent following block range in
 241  *                             extents status tree
 242  *
 243  * @inode - file containing the range
 244  * @matching_fn - pointer to function that matches extents with desired status
 245  * @lblk - logical block defining start of range
 246  * @end - logical block defining end of range
 247  * @es - extent found, if any
 248  *
 249  * Find the first extent within the block range specified by @lblk and @end
 250  * in the extents status tree that satisfies @matching_fn.  If a match
 251  * is found, it's returned in @es.  If not, and a matching extent is found
 252  * beyond the block range, it's returned in @es.  If no match is found, an
 253  * extent is returned in @es whose es_lblk, es_len, and es_pblk components
 254  * are 0.
 255  */
 256 static void __es_find_extent_range(struct inode *inode,
 257                                    int (*matching_fn)(struct extent_status *es),
 258                                    ext4_lblk_t lblk, ext4_lblk_t end,
 259                                    struct extent_status *es)
 260 {
 261         struct ext4_es_tree *tree = NULL;
 262         struct extent_status *es1 = NULL;
 263         struct rb_node *node;
 264 
 265         WARN_ON(es == NULL);
 266         WARN_ON(end < lblk);
 267 
 268         tree = &EXT4_I(inode)->i_es_tree;
 269 
 270         /* see if the extent has been cached */
 271         es->es_lblk = es->es_len = es->es_pblk = 0;
 272         if (tree->cache_es) {
 273                 es1 = tree->cache_es;
 274                 if (in_range(lblk, es1->es_lblk, es1->es_len)) {
 275                         es_debug("%u cached by [%u/%u) %llu %x\n",
 276                                  lblk, es1->es_lblk, es1->es_len,
 277                                  ext4_es_pblock(es1), ext4_es_status(es1));
 278                         goto out;
 279                 }
 280         }
 281 
 282         es1 = __es_tree_search(&tree->root, lblk);
 283 
 284 out:
 285         if (es1 && !matching_fn(es1)) {
 286                 while ((node = rb_next(&es1->rb_node)) != NULL) {
 287                         es1 = rb_entry(node, struct extent_status, rb_node);
 288                         if (es1->es_lblk > end) {
 289                                 es1 = NULL;
 290                                 break;
 291                         }
 292                         if (matching_fn(es1))
 293                                 break;
 294                 }
 295         }
 296 
 297         if (es1 && matching_fn(es1)) {
 298                 tree->cache_es = es1;
 299                 es->es_lblk = es1->es_lblk;
 300                 es->es_len = es1->es_len;
 301                 es->es_pblk = es1->es_pblk;
 302         }
 303 
 304 }
 305 
 306 /*
 307  * Locking for __es_find_extent_range() for external use
 308  */
 309 void ext4_es_find_extent_range(struct inode *inode,
 310                                int (*matching_fn)(struct extent_status *es),
 311                                ext4_lblk_t lblk, ext4_lblk_t end,
 312                                struct extent_status *es)
 313 {
 314         trace_ext4_es_find_extent_range_enter(inode, lblk);
 315 
 316         read_lock(&EXT4_I(inode)->i_es_lock);
 317         __es_find_extent_range(inode, matching_fn, lblk, end, es);
 318         read_unlock(&EXT4_I(inode)->i_es_lock);
 319 
 320         trace_ext4_es_find_extent_range_exit(inode, es);
 321 }
 322 
 323 /*
 324  * __es_scan_range - search block range for block with specified status
 325  *                   in extents status tree
 326  *
 327  * @inode - file containing the range
 328  * @matching_fn - pointer to function that matches extents with desired status
 329  * @lblk - logical block defining start of range
 330  * @end - logical block defining end of range
 331  *
 332  * Returns true if at least one block in the specified block range satisfies
 333  * the criterion specified by @matching_fn, and false if not.  If at least
 334  * one extent has the specified status, then there is at least one block
 335  * in the cluster with that status.  Should only be called by code that has
 336  * taken i_es_lock.
 337  */
 338 static bool __es_scan_range(struct inode *inode,
 339                             int (*matching_fn)(struct extent_status *es),
 340                             ext4_lblk_t start, ext4_lblk_t end)
 341 {
 342         struct extent_status es;
 343 
 344         __es_find_extent_range(inode, matching_fn, start, end, &es);
 345         if (es.es_len == 0)
 346                 return false;   /* no matching extent in the tree */
 347         else if (es.es_lblk <= start &&
 348                  start < es.es_lblk + es.es_len)
 349                 return true;
 350         else if (start <= es.es_lblk && es.es_lblk <= end)
 351                 return true;
 352         else
 353                 return false;
 354 }
 355 /*
 356  * Locking for __es_scan_range() for external use
 357  */
 358 bool ext4_es_scan_range(struct inode *inode,
 359                         int (*matching_fn)(struct extent_status *es),
 360                         ext4_lblk_t lblk, ext4_lblk_t end)
 361 {
 362         bool ret;
 363 
 364         read_lock(&EXT4_I(inode)->i_es_lock);
 365         ret = __es_scan_range(inode, matching_fn, lblk, end);
 366         read_unlock(&EXT4_I(inode)->i_es_lock);
 367 
 368         return ret;
 369 }
 370 
 371 /*
 372  * __es_scan_clu - search cluster for block with specified status in
 373  *                 extents status tree
 374  *
 375  * @inode - file containing the cluster
 376  * @matching_fn - pointer to function that matches extents with desired status
 377  * @lblk - logical block in cluster to be searched
 378  *
 379  * Returns true if at least one extent in the cluster containing @lblk
 380  * satisfies the criterion specified by @matching_fn, and false if not.  If at
 381  * least one extent has the specified status, then there is at least one block
 382  * in the cluster with that status.  Should only be called by code that has
 383  * taken i_es_lock.
 384  */
 385 static bool __es_scan_clu(struct inode *inode,
 386                           int (*matching_fn)(struct extent_status *es),
 387                           ext4_lblk_t lblk)
 388 {
 389         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 390         ext4_lblk_t lblk_start, lblk_end;
 391 
 392         lblk_start = EXT4_LBLK_CMASK(sbi, lblk);
 393         lblk_end = lblk_start + sbi->s_cluster_ratio - 1;
 394 
 395         return __es_scan_range(inode, matching_fn, lblk_start, lblk_end);
 396 }
 397 
 398 /*
 399  * Locking for __es_scan_clu() for external use
 400  */
 401 bool ext4_es_scan_clu(struct inode *inode,
 402                       int (*matching_fn)(struct extent_status *es),
 403                       ext4_lblk_t lblk)
 404 {
 405         bool ret;
 406 
 407         read_lock(&EXT4_I(inode)->i_es_lock);
 408         ret = __es_scan_clu(inode, matching_fn, lblk);
 409         read_unlock(&EXT4_I(inode)->i_es_lock);
 410 
 411         return ret;
 412 }
 413 
 414 static void ext4_es_list_add(struct inode *inode)
 415 {
 416         struct ext4_inode_info *ei = EXT4_I(inode);
 417         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 418 
 419         if (!list_empty(&ei->i_es_list))
 420                 return;
 421 
 422         spin_lock(&sbi->s_es_lock);
 423         if (list_empty(&ei->i_es_list)) {
 424                 list_add_tail(&ei->i_es_list, &sbi->s_es_list);
 425                 sbi->s_es_nr_inode++;
 426         }
 427         spin_unlock(&sbi->s_es_lock);
 428 }
 429 
 430 static void ext4_es_list_del(struct inode *inode)
 431 {
 432         struct ext4_inode_info *ei = EXT4_I(inode);
 433         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 434 
 435         spin_lock(&sbi->s_es_lock);
 436         if (!list_empty(&ei->i_es_list)) {
 437                 list_del_init(&ei->i_es_list);
 438                 sbi->s_es_nr_inode--;
 439                 WARN_ON_ONCE(sbi->s_es_nr_inode < 0);
 440         }
 441         spin_unlock(&sbi->s_es_lock);
 442 }
 443 
 444 static struct extent_status *
 445 ext4_es_alloc_extent(struct inode *inode, ext4_lblk_t lblk, ext4_lblk_t len,
 446                      ext4_fsblk_t pblk)
 447 {
 448         struct extent_status *es;
 449         es = kmem_cache_alloc(ext4_es_cachep, GFP_ATOMIC);
 450         if (es == NULL)
 451                 return NULL;
 452         es->es_lblk = lblk;
 453         es->es_len = len;
 454         es->es_pblk = pblk;
 455 
 456         /*
 457          * We don't count delayed extent because we never try to reclaim them
 458          */
 459         if (!ext4_es_is_delayed(es)) {
 460                 if (!EXT4_I(inode)->i_es_shk_nr++)
 461                         ext4_es_list_add(inode);
 462                 percpu_counter_inc(&EXT4_SB(inode->i_sb)->
 463                                         s_es_stats.es_stats_shk_cnt);
 464         }
 465 
 466         EXT4_I(inode)->i_es_all_nr++;
 467         percpu_counter_inc(&EXT4_SB(inode->i_sb)->s_es_stats.es_stats_all_cnt);
 468 
 469         return es;
 470 }
 471 
 472 static void ext4_es_free_extent(struct inode *inode, struct extent_status *es)
 473 {
 474         EXT4_I(inode)->i_es_all_nr--;
 475         percpu_counter_dec(&EXT4_SB(inode->i_sb)->s_es_stats.es_stats_all_cnt);
 476 
 477         /* Decrease the shrink counter when this es is not delayed */
 478         if (!ext4_es_is_delayed(es)) {
 479                 BUG_ON(EXT4_I(inode)->i_es_shk_nr == 0);
 480                 if (!--EXT4_I(inode)->i_es_shk_nr)
 481                         ext4_es_list_del(inode);
 482                 percpu_counter_dec(&EXT4_SB(inode->i_sb)->
 483                                         s_es_stats.es_stats_shk_cnt);
 484         }
 485 
 486         kmem_cache_free(ext4_es_cachep, es);
 487 }
 488 
 489 /*
 490  * Check whether or not two extents can be merged
 491  * Condition:
 492  *  - logical block number is contiguous
 493  *  - physical block number is contiguous
 494  *  - status is equal
 495  */
 496 static int ext4_es_can_be_merged(struct extent_status *es1,
 497                                  struct extent_status *es2)
 498 {
 499         if (ext4_es_type(es1) != ext4_es_type(es2))
 500                 return 0;
 501 
 502         if (((__u64) es1->es_len) + es2->es_len > EXT_MAX_BLOCKS) {
 503                 pr_warn("ES assertion failed when merging extents. "
 504                         "The sum of lengths of es1 (%d) and es2 (%d) "
 505                         "is bigger than allowed file size (%d)\n",
 506                         es1->es_len, es2->es_len, EXT_MAX_BLOCKS);
 507                 WARN_ON(1);
 508                 return 0;
 509         }
 510 
 511         if (((__u64) es1->es_lblk) + es1->es_len != es2->es_lblk)
 512                 return 0;
 513 
 514         if ((ext4_es_is_written(es1) || ext4_es_is_unwritten(es1)) &&
 515             (ext4_es_pblock(es1) + es1->es_len == ext4_es_pblock(es2)))
 516                 return 1;
 517 
 518         if (ext4_es_is_hole(es1))
 519                 return 1;
 520 
 521         /* we need to check delayed extent is without unwritten status */
 522         if (ext4_es_is_delayed(es1) && !ext4_es_is_unwritten(es1))
 523                 return 1;
 524 
 525         return 0;
 526 }
 527 
 528 static struct extent_status *
 529 ext4_es_try_to_merge_left(struct inode *inode, struct extent_status *es)
 530 {
 531         struct ext4_es_tree *tree = &EXT4_I(inode)->i_es_tree;
 532         struct extent_status *es1;
 533         struct rb_node *node;
 534 
 535         node = rb_prev(&es->rb_node);
 536         if (!node)
 537                 return es;
 538 
 539         es1 = rb_entry(node, struct extent_status, rb_node);
 540         if (ext4_es_can_be_merged(es1, es)) {
 541                 es1->es_len += es->es_len;
 542                 if (ext4_es_is_referenced(es))
 543                         ext4_es_set_referenced(es1);
 544                 rb_erase(&es->rb_node, &tree->root);
 545                 ext4_es_free_extent(inode, es);
 546                 es = es1;
 547         }
 548 
 549         return es;
 550 }
 551 
 552 static struct extent_status *
 553 ext4_es_try_to_merge_right(struct inode *inode, struct extent_status *es)
 554 {
 555         struct ext4_es_tree *tree = &EXT4_I(inode)->i_es_tree;
 556         struct extent_status *es1;
 557         struct rb_node *node;
 558 
 559         node = rb_next(&es->rb_node);
 560         if (!node)
 561                 return es;
 562 
 563         es1 = rb_entry(node, struct extent_status, rb_node);
 564         if (ext4_es_can_be_merged(es, es1)) {
 565                 es->es_len += es1->es_len;
 566                 if (ext4_es_is_referenced(es1))
 567                         ext4_es_set_referenced(es);
 568                 rb_erase(node, &tree->root);
 569                 ext4_es_free_extent(inode, es1);
 570         }
 571 
 572         return es;
 573 }
 574 
 575 #ifdef ES_AGGRESSIVE_TEST
 576 #include "ext4_extents.h"       /* Needed when ES_AGGRESSIVE_TEST is defined */
 577 
 578 static void ext4_es_insert_extent_ext_check(struct inode *inode,
 579                                             struct extent_status *es)
 580 {
 581         struct ext4_ext_path *path = NULL;
 582         struct ext4_extent *ex;
 583         ext4_lblk_t ee_block;
 584         ext4_fsblk_t ee_start;
 585         unsigned short ee_len;
 586         int depth, ee_status, es_status;
 587 
 588         path = ext4_find_extent(inode, es->es_lblk, NULL, EXT4_EX_NOCACHE);
 589         if (IS_ERR(path))
 590                 return;
 591 
 592         depth = ext_depth(inode);
 593         ex = path[depth].p_ext;
 594 
 595         if (ex) {
 596 
 597                 ee_block = le32_to_cpu(ex->ee_block);
 598                 ee_start = ext4_ext_pblock(ex);
 599                 ee_len = ext4_ext_get_actual_len(ex);
 600 
 601                 ee_status = ext4_ext_is_unwritten(ex) ? 1 : 0;
 602                 es_status = ext4_es_is_unwritten(es) ? 1 : 0;
 603 
 604                 /*
 605                  * Make sure ex and es are not overlap when we try to insert
 606                  * a delayed/hole extent.
 607                  */
 608                 if (!ext4_es_is_written(es) && !ext4_es_is_unwritten(es)) {
 609                         if (in_range(es->es_lblk, ee_block, ee_len)) {
 610                                 pr_warn("ES insert assertion failed for "
 611                                         "inode: %lu we can find an extent "
 612                                         "at block [%d/%d/%llu/%c], but we "
 613                                         "want to add a delayed/hole extent "
 614                                         "[%d/%d/%llu/%x]\n",
 615                                         inode->i_ino, ee_block, ee_len,
 616                                         ee_start, ee_status ? 'u' : 'w',
 617                                         es->es_lblk, es->es_len,
 618                                         ext4_es_pblock(es), ext4_es_status(es));
 619                         }
 620                         goto out;
 621                 }
 622 
 623                 /*
 624                  * We don't check ee_block == es->es_lblk, etc. because es
 625                  * might be a part of whole extent, vice versa.
 626                  */
 627                 if (es->es_lblk < ee_block ||
 628                     ext4_es_pblock(es) != ee_start + es->es_lblk - ee_block) {
 629                         pr_warn("ES insert assertion failed for inode: %lu "
 630                                 "ex_status [%d/%d/%llu/%c] != "
 631                                 "es_status [%d/%d/%llu/%c]\n", inode->i_ino,
 632                                 ee_block, ee_len, ee_start,
 633                                 ee_status ? 'u' : 'w', es->es_lblk, es->es_len,
 634                                 ext4_es_pblock(es), es_status ? 'u' : 'w');
 635                         goto out;
 636                 }
 637 
 638                 if (ee_status ^ es_status) {
 639                         pr_warn("ES insert assertion failed for inode: %lu "
 640                                 "ex_status [%d/%d/%llu/%c] != "
 641                                 "es_status [%d/%d/%llu/%c]\n", inode->i_ino,
 642                                 ee_block, ee_len, ee_start,
 643                                 ee_status ? 'u' : 'w', es->es_lblk, es->es_len,
 644                                 ext4_es_pblock(es), es_status ? 'u' : 'w');
 645                 }
 646         } else {
 647                 /*
 648                  * We can't find an extent on disk.  So we need to make sure
 649                  * that we don't want to add an written/unwritten extent.
 650                  */
 651                 if (!ext4_es_is_delayed(es) && !ext4_es_is_hole(es)) {
 652                         pr_warn("ES insert assertion failed for inode: %lu "
 653                                 "can't find an extent at block %d but we want "
 654                                 "to add a written/unwritten extent "
 655                                 "[%d/%d/%llu/%x]\n", inode->i_ino,
 656                                 es->es_lblk, es->es_lblk, es->es_len,
 657                                 ext4_es_pblock(es), ext4_es_status(es));
 658                 }
 659         }
 660 out:
 661         ext4_ext_drop_refs(path);
 662         kfree(path);
 663 }
 664 
 665 static void ext4_es_insert_extent_ind_check(struct inode *inode,
 666                                             struct extent_status *es)
 667 {
 668         struct ext4_map_blocks map;
 669         int retval;
 670 
 671         /*
 672          * Here we call ext4_ind_map_blocks to lookup a block mapping because
 673          * 'Indirect' structure is defined in indirect.c.  So we couldn't
 674          * access direct/indirect tree from outside.  It is too dirty to define
 675          * this function in indirect.c file.
 676          */
 677 
 678         map.m_lblk = es->es_lblk;
 679         map.m_len = es->es_len;
 680 
 681         retval = ext4_ind_map_blocks(NULL, inode, &map, 0);
 682         if (retval > 0) {
 683                 if (ext4_es_is_delayed(es) || ext4_es_is_hole(es)) {
 684                         /*
 685                          * We want to add a delayed/hole extent but this
 686                          * block has been allocated.
 687                          */
 688                         pr_warn("ES insert assertion failed for inode: %lu "
 689                                 "We can find blocks but we want to add a "
 690                                 "delayed/hole extent [%d/%d/%llu/%x]\n",
 691                                 inode->i_ino, es->es_lblk, es->es_len,
 692                                 ext4_es_pblock(es), ext4_es_status(es));
 693                         return;
 694                 } else if (ext4_es_is_written(es)) {
 695                         if (retval != es->es_len) {
 696                                 pr_warn("ES insert assertion failed for "
 697                                         "inode: %lu retval %d != es_len %d\n",
 698                                         inode->i_ino, retval, es->es_len);
 699                                 return;
 700                         }
 701                         if (map.m_pblk != ext4_es_pblock(es)) {
 702                                 pr_warn("ES insert assertion failed for "
 703                                         "inode: %lu m_pblk %llu != "
 704                                         "es_pblk %llu\n",
 705                                         inode->i_ino, map.m_pblk,
 706                                         ext4_es_pblock(es));
 707                                 return;
 708                         }
 709                 } else {
 710                         /*
 711                          * We don't need to check unwritten extent because
 712                          * indirect-based file doesn't have it.
 713                          */
 714                         BUG();
 715                 }
 716         } else if (retval == 0) {
 717                 if (ext4_es_is_written(es)) {
 718                         pr_warn("ES insert assertion failed for inode: %lu "
 719                                 "We can't find the block but we want to add "
 720                                 "a written extent [%d/%d/%llu/%x]\n",
 721                                 inode->i_ino, es->es_lblk, es->es_len,
 722                                 ext4_es_pblock(es), ext4_es_status(es));
 723                         return;
 724                 }
 725         }
 726 }
 727 
 728 static inline void ext4_es_insert_extent_check(struct inode *inode,
 729                                                struct extent_status *es)
 730 {
 731         /*
 732          * We don't need to worry about the race condition because
 733          * caller takes i_data_sem locking.
 734          */
 735         BUG_ON(!rwsem_is_locked(&EXT4_I(inode)->i_data_sem));
 736         if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
 737                 ext4_es_insert_extent_ext_check(inode, es);
 738         else
 739                 ext4_es_insert_extent_ind_check(inode, es);
 740 }
 741 #else
 742 static inline void ext4_es_insert_extent_check(struct inode *inode,
 743                                                struct extent_status *es)
 744 {
 745 }
 746 #endif
 747 
 748 static int __es_insert_extent(struct inode *inode, struct extent_status *newes)
 749 {
 750         struct ext4_es_tree *tree = &EXT4_I(inode)->i_es_tree;
 751         struct rb_node **p = &tree->root.rb_node;
 752         struct rb_node *parent = NULL;
 753         struct extent_status *es;
 754 
 755         while (*p) {
 756                 parent = *p;
 757                 es = rb_entry(parent, struct extent_status, rb_node);
 758 
 759                 if (newes->es_lblk < es->es_lblk) {
 760                         if (ext4_es_can_be_merged(newes, es)) {
 761                                 /*
 762                                  * Here we can modify es_lblk directly
 763                                  * because it isn't overlapped.
 764                                  */
 765                                 es->es_lblk = newes->es_lblk;
 766                                 es->es_len += newes->es_len;
 767                                 if (ext4_es_is_written(es) ||
 768                                     ext4_es_is_unwritten(es))
 769                                         ext4_es_store_pblock(es,
 770                                                              newes->es_pblk);
 771                                 es = ext4_es_try_to_merge_left(inode, es);
 772                                 goto out;
 773                         }
 774                         p = &(*p)->rb_left;
 775                 } else if (newes->es_lblk > ext4_es_end(es)) {
 776                         if (ext4_es_can_be_merged(es, newes)) {
 777                                 es->es_len += newes->es_len;
 778                                 es = ext4_es_try_to_merge_right(inode, es);
 779                                 goto out;
 780                         }
 781                         p = &(*p)->rb_right;
 782                 } else {
 783                         BUG();
 784                         return -EINVAL;
 785                 }
 786         }
 787 
 788         es = ext4_es_alloc_extent(inode, newes->es_lblk, newes->es_len,
 789                                   newes->es_pblk);
 790         if (!es)
 791                 return -ENOMEM;
 792         rb_link_node(&es->rb_node, parent, p);
 793         rb_insert_color(&es->rb_node, &tree->root);
 794 
 795 out:
 796         tree->cache_es = es;
 797         return 0;
 798 }
 799 
 800 /*
 801  * ext4_es_insert_extent() adds information to an inode's extent
 802  * status tree.
 803  *
 804  * Return 0 on success, error code on failure.
 805  */
 806 int ext4_es_insert_extent(struct inode *inode, ext4_lblk_t lblk,
 807                           ext4_lblk_t len, ext4_fsblk_t pblk,
 808                           unsigned int status)
 809 {
 810         struct extent_status newes;
 811         ext4_lblk_t end = lblk + len - 1;
 812         int err = 0;
 813         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 814 
 815         es_debug("add [%u/%u) %llu %x to extent status tree of inode %lu\n",
 816                  lblk, len, pblk, status, inode->i_ino);
 817 
 818         if (!len)
 819                 return 0;
 820 
 821         BUG_ON(end < lblk);
 822 
 823         if ((status & EXTENT_STATUS_DELAYED) &&
 824             (status & EXTENT_STATUS_WRITTEN)) {
 825                 ext4_warning(inode->i_sb, "Inserting extent [%u/%u] as "
 826                                 " delayed and written which can potentially "
 827                                 " cause data loss.", lblk, len);
 828                 WARN_ON(1);
 829         }
 830 
 831         newes.es_lblk = lblk;
 832         newes.es_len = len;
 833         ext4_es_store_pblock_status(&newes, pblk, status);
 834         trace_ext4_es_insert_extent(inode, &newes);
 835 
 836         ext4_es_insert_extent_check(inode, &newes);
 837 
 838         write_lock(&EXT4_I(inode)->i_es_lock);
 839         err = __es_remove_extent(inode, lblk, end, NULL);
 840         if (err != 0)
 841                 goto error;
 842 retry:
 843         err = __es_insert_extent(inode, &newes);
 844         if (err == -ENOMEM && __es_shrink(EXT4_SB(inode->i_sb),
 845                                           128, EXT4_I(inode)))
 846                 goto retry;
 847         if (err == -ENOMEM && !ext4_es_is_delayed(&newes))
 848                 err = 0;
 849 
 850         if (sbi->s_cluster_ratio > 1 && test_opt(inode->i_sb, DELALLOC) &&
 851             (status & EXTENT_STATUS_WRITTEN ||
 852              status & EXTENT_STATUS_UNWRITTEN))
 853                 __revise_pending(inode, lblk, len);
 854 
 855 error:
 856         write_unlock(&EXT4_I(inode)->i_es_lock);
 857 
 858         ext4_es_print_tree(inode);
 859 
 860         return err;
 861 }
 862 
 863 /*
 864  * ext4_es_cache_extent() inserts information into the extent status
 865  * tree if and only if there isn't information about the range in
 866  * question already.
 867  */
 868 void ext4_es_cache_extent(struct inode *inode, ext4_lblk_t lblk,
 869                           ext4_lblk_t len, ext4_fsblk_t pblk,
 870                           unsigned int status)
 871 {
 872         struct extent_status *es;
 873         struct extent_status newes;
 874         ext4_lblk_t end = lblk + len - 1;
 875 
 876         newes.es_lblk = lblk;
 877         newes.es_len = len;
 878         ext4_es_store_pblock_status(&newes, pblk, status);
 879         trace_ext4_es_cache_extent(inode, &newes);
 880 
 881         if (!len)
 882                 return;
 883 
 884         BUG_ON(end < lblk);
 885 
 886         write_lock(&EXT4_I(inode)->i_es_lock);
 887 
 888         es = __es_tree_search(&EXT4_I(inode)->i_es_tree.root, lblk);
 889         if (!es || es->es_lblk > end)
 890                 __es_insert_extent(inode, &newes);
 891         write_unlock(&EXT4_I(inode)->i_es_lock);
 892 }
 893 
 894 /*
 895  * ext4_es_lookup_extent() looks up an extent in extent status tree.
 896  *
 897  * ext4_es_lookup_extent is called by ext4_map_blocks/ext4_da_map_blocks.
 898  *
 899  * Return: 1 on found, 0 on not
 900  */
 901 int ext4_es_lookup_extent(struct inode *inode, ext4_lblk_t lblk,
 902                           ext4_lblk_t *next_lblk,
 903                           struct extent_status *es)
 904 {
 905         struct ext4_es_tree *tree;
 906         struct ext4_es_stats *stats;
 907         struct extent_status *es1 = NULL;
 908         struct rb_node *node;
 909         int found = 0;
 910 
 911         trace_ext4_es_lookup_extent_enter(inode, lblk);
 912         es_debug("lookup extent in block %u\n", lblk);
 913 
 914         tree = &EXT4_I(inode)->i_es_tree;
 915         read_lock(&EXT4_I(inode)->i_es_lock);
 916 
 917         /* find extent in cache firstly */
 918         es->es_lblk = es->es_len = es->es_pblk = 0;
 919         if (tree->cache_es) {
 920                 es1 = tree->cache_es;
 921                 if (in_range(lblk, es1->es_lblk, es1->es_len)) {
 922                         es_debug("%u cached by [%u/%u)\n",
 923                                  lblk, es1->es_lblk, es1->es_len);
 924                         found = 1;
 925                         goto out;
 926                 }
 927         }
 928 
 929         node = tree->root.rb_node;
 930         while (node) {
 931                 es1 = rb_entry(node, struct extent_status, rb_node);
 932                 if (lblk < es1->es_lblk)
 933                         node = node->rb_left;
 934                 else if (lblk > ext4_es_end(es1))
 935                         node = node->rb_right;
 936                 else {
 937                         found = 1;
 938                         break;
 939                 }
 940         }
 941 
 942 out:
 943         stats = &EXT4_SB(inode->i_sb)->s_es_stats;
 944         if (found) {
 945                 BUG_ON(!es1);
 946                 es->es_lblk = es1->es_lblk;
 947                 es->es_len = es1->es_len;
 948                 es->es_pblk = es1->es_pblk;
 949                 if (!ext4_es_is_referenced(es1))
 950                         ext4_es_set_referenced(es1);
 951                 percpu_counter_inc(&stats->es_stats_cache_hits);
 952                 if (next_lblk) {
 953                         node = rb_next(&es1->rb_node);
 954                         if (node) {
 955                                 es1 = rb_entry(node, struct extent_status,
 956                                                rb_node);
 957                                 *next_lblk = es1->es_lblk;
 958                         } else
 959                                 *next_lblk = 0;
 960                 }
 961         } else {
 962                 percpu_counter_inc(&stats->es_stats_cache_misses);
 963         }
 964 
 965         read_unlock(&EXT4_I(inode)->i_es_lock);
 966 
 967         trace_ext4_es_lookup_extent_exit(inode, es, found);
 968         return found;
 969 }
 970 
 971 struct rsvd_count {
 972         int ndelonly;
 973         bool first_do_lblk_found;
 974         ext4_lblk_t first_do_lblk;
 975         ext4_lblk_t last_do_lblk;
 976         struct extent_status *left_es;
 977         bool partial;
 978         ext4_lblk_t lclu;
 979 };
 980 
 981 /*
 982  * init_rsvd - initialize reserved count data before removing block range
 983  *             in file from extent status tree
 984  *
 985  * @inode - file containing range
 986  * @lblk - first block in range
 987  * @es - pointer to first extent in range
 988  * @rc - pointer to reserved count data
 989  *
 990  * Assumes es is not NULL
 991  */
 992 static void init_rsvd(struct inode *inode, ext4_lblk_t lblk,
 993                       struct extent_status *es, struct rsvd_count *rc)
 994 {
 995         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 996         struct rb_node *node;
 997 
 998         rc->ndelonly = 0;
 999 
1000         /*
1001          * for bigalloc, note the first delonly block in the range has not
1002          * been found, record the extent containing the block to the left of
1003          * the region to be removed, if any, and note that there's no partial
1004          * cluster to track
1005          */
1006         if (sbi->s_cluster_ratio > 1) {
1007                 rc->first_do_lblk_found = false;
1008                 if (lblk > es->es_lblk) {
1009                         rc->left_es = es;
1010                 } else {
1011                         node = rb_prev(&es->rb_node);
1012                         rc->left_es = node ? rb_entry(node,
1013                                                       struct extent_status,
1014                                                       rb_node) : NULL;
1015                 }
1016                 rc->partial = false;
1017         }
1018 }
1019 
1020 /*
1021  * count_rsvd - count the clusters containing delayed and not unwritten
1022  *              (delonly) blocks in a range within an extent and add to
1023  *              the running tally in rsvd_count
1024  *
1025  * @inode - file containing extent
1026  * @lblk - first block in range
1027  * @len - length of range in blocks
1028  * @es - pointer to extent containing clusters to be counted
1029  * @rc - pointer to reserved count data
1030  *
1031  * Tracks partial clusters found at the beginning and end of extents so
1032  * they aren't overcounted when they span adjacent extents
1033  */
1034 static void count_rsvd(struct inode *inode, ext4_lblk_t lblk, long len,
1035                        struct extent_status *es, struct rsvd_count *rc)
1036 {
1037         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1038         ext4_lblk_t i, end, nclu;
1039 
1040         if (!ext4_es_is_delonly(es))
1041                 return;
1042 
1043         WARN_ON(len <= 0);
1044 
1045         if (sbi->s_cluster_ratio == 1) {
1046                 rc->ndelonly += (int) len;
1047                 return;
1048         }
1049 
1050         /* bigalloc */
1051 
1052         i = (lblk < es->es_lblk) ? es->es_lblk : lblk;
1053         end = lblk + (ext4_lblk_t) len - 1;
1054         end = (end > ext4_es_end(es)) ? ext4_es_end(es) : end;
1055 
1056         /* record the first block of the first delonly extent seen */
1057         if (rc->first_do_lblk_found == false) {
1058                 rc->first_do_lblk = i;
1059                 rc->first_do_lblk_found = true;
1060         }
1061 
1062         /* update the last lblk in the region seen so far */
1063         rc->last_do_lblk = end;
1064 
1065         /*
1066          * if we're tracking a partial cluster and the current extent
1067          * doesn't start with it, count it and stop tracking
1068          */
1069         if (rc->partial && (rc->lclu != EXT4_B2C(sbi, i))) {
1070                 rc->ndelonly++;
1071                 rc->partial = false;
1072         }
1073 
1074         /*
1075          * if the first cluster doesn't start on a cluster boundary but
1076          * ends on one, count it
1077          */
1078         if (EXT4_LBLK_COFF(sbi, i) != 0) {
1079                 if (end >= EXT4_LBLK_CFILL(sbi, i)) {
1080                         rc->ndelonly++;
1081                         rc->partial = false;
1082                         i = EXT4_LBLK_CFILL(sbi, i) + 1;
1083                 }
1084         }
1085 
1086         /*
1087          * if the current cluster starts on a cluster boundary, count the
1088          * number of whole delonly clusters in the extent
1089          */
1090         if ((i + sbi->s_cluster_ratio - 1) <= end) {
1091                 nclu = (end - i + 1) >> sbi->s_cluster_bits;
1092                 rc->ndelonly += nclu;
1093                 i += nclu << sbi->s_cluster_bits;
1094         }
1095 
1096         /*
1097          * start tracking a partial cluster if there's a partial at the end
1098          * of the current extent and we're not already tracking one
1099          */
1100         if (!rc->partial && i <= end) {
1101                 rc->partial = true;
1102                 rc->lclu = EXT4_B2C(sbi, i);
1103         }
1104 }
1105 
1106 /*
1107  * __pr_tree_search - search for a pending cluster reservation
1108  *
1109  * @root - root of pending reservation tree
1110  * @lclu - logical cluster to search for
1111  *
1112  * Returns the pending reservation for the cluster identified by @lclu
1113  * if found.  If not, returns a reservation for the next cluster if any,
1114  * and if not, returns NULL.
1115  */
1116 static struct pending_reservation *__pr_tree_search(struct rb_root *root,
1117                                                     ext4_lblk_t lclu)
1118 {
1119         struct rb_node *node = root->rb_node;
1120         struct pending_reservation *pr = NULL;
1121 
1122         while (node) {
1123                 pr = rb_entry(node, struct pending_reservation, rb_node);
1124                 if (lclu < pr->lclu)
1125                         node = node->rb_left;
1126                 else if (lclu > pr->lclu)
1127                         node = node->rb_right;
1128                 else
1129                         return pr;
1130         }
1131         if (pr && lclu < pr->lclu)
1132                 return pr;
1133         if (pr && lclu > pr->lclu) {
1134                 node = rb_next(&pr->rb_node);
1135                 return node ? rb_entry(node, struct pending_reservation,
1136                                        rb_node) : NULL;
1137         }
1138         return NULL;
1139 }
1140 
1141 /*
1142  * get_rsvd - calculates and returns the number of cluster reservations to be
1143  *            released when removing a block range from the extent status tree
1144  *            and releases any pending reservations within the range
1145  *
1146  * @inode - file containing block range
1147  * @end - last block in range
1148  * @right_es - pointer to extent containing next block beyond end or NULL
1149  * @rc - pointer to reserved count data
1150  *
1151  * The number of reservations to be released is equal to the number of
1152  * clusters containing delayed and not unwritten (delonly) blocks within
1153  * the range, minus the number of clusters still containing delonly blocks
1154  * at the ends of the range, and minus the number of pending reservations
1155  * within the range.
1156  */
1157 static unsigned int get_rsvd(struct inode *inode, ext4_lblk_t end,
1158                              struct extent_status *right_es,
1159                              struct rsvd_count *rc)
1160 {
1161         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1162         struct pending_reservation *pr;
1163         struct ext4_pending_tree *tree = &EXT4_I(inode)->i_pending_tree;
1164         struct rb_node *node;
1165         ext4_lblk_t first_lclu, last_lclu;
1166         bool left_delonly, right_delonly, count_pending;
1167         struct extent_status *es;
1168 
1169         if (sbi->s_cluster_ratio > 1) {
1170                 /* count any remaining partial cluster */
1171                 if (rc->partial)
1172                         rc->ndelonly++;
1173 
1174                 if (rc->ndelonly == 0)
1175                         return 0;
1176 
1177                 first_lclu = EXT4_B2C(sbi, rc->first_do_lblk);
1178                 last_lclu = EXT4_B2C(sbi, rc->last_do_lblk);
1179 
1180                 /*
1181                  * decrease the delonly count by the number of clusters at the
1182                  * ends of the range that still contain delonly blocks -
1183                  * these clusters still need to be reserved
1184                  */
1185                 left_delonly = right_delonly = false;
1186 
1187                 es = rc->left_es;
1188                 while (es && ext4_es_end(es) >=
1189                        EXT4_LBLK_CMASK(sbi, rc->first_do_lblk)) {
1190                         if (ext4_es_is_delonly(es)) {
1191                                 rc->ndelonly--;
1192                                 left_delonly = true;
1193                                 break;
1194                         }
1195                         node = rb_prev(&es->rb_node);
1196                         if (!node)
1197                                 break;
1198                         es = rb_entry(node, struct extent_status, rb_node);
1199                 }
1200                 if (right_es && (!left_delonly || first_lclu != last_lclu)) {
1201                         if (end < ext4_es_end(right_es)) {
1202                                 es = right_es;
1203                         } else {
1204                                 node = rb_next(&right_es->rb_node);
1205                                 es = node ? rb_entry(node, struct extent_status,
1206                                                      rb_node) : NULL;
1207                         }
1208                         while (es && es->es_lblk <=
1209                                EXT4_LBLK_CFILL(sbi, rc->last_do_lblk)) {
1210                                 if (ext4_es_is_delonly(es)) {
1211                                         rc->ndelonly--;
1212                                         right_delonly = true;
1213                                         break;
1214                                 }
1215                                 node = rb_next(&es->rb_node);
1216                                 if (!node)
1217                                         break;
1218                                 es = rb_entry(node, struct extent_status,
1219                                               rb_node);
1220                         }
1221                 }
1222 
1223                 /*
1224                  * Determine the block range that should be searched for
1225                  * pending reservations, if any.  Clusters on the ends of the
1226                  * original removed range containing delonly blocks are
1227                  * excluded.  They've already been accounted for and it's not
1228                  * possible to determine if an associated pending reservation
1229                  * should be released with the information available in the
1230                  * extents status tree.
1231                  */
1232                 if (first_lclu == last_lclu) {
1233                         if (left_delonly | right_delonly)
1234                                 count_pending = false;
1235                         else
1236                                 count_pending = true;
1237                 } else {
1238                         if (left_delonly)
1239                                 first_lclu++;
1240                         if (right_delonly)
1241                                 last_lclu--;
1242                         if (first_lclu <= last_lclu)
1243                                 count_pending = true;
1244                         else
1245                                 count_pending = false;
1246                 }
1247 
1248                 /*
1249                  * a pending reservation found between first_lclu and last_lclu
1250                  * represents an allocated cluster that contained at least one
1251                  * delonly block, so the delonly total must be reduced by one
1252                  * for each pending reservation found and released
1253                  */
1254                 if (count_pending) {
1255                         pr = __pr_tree_search(&tree->root, first_lclu);
1256                         while (pr && pr->lclu <= last_lclu) {
1257                                 rc->ndelonly--;
1258                                 node = rb_next(&pr->rb_node);
1259                                 rb_erase(&pr->rb_node, &tree->root);
1260                                 kmem_cache_free(ext4_pending_cachep, pr);
1261                                 if (!node)
1262                                         break;
1263                                 pr = rb_entry(node, struct pending_reservation,
1264                                               rb_node);
1265                         }
1266                 }
1267         }
1268         return rc->ndelonly;
1269 }
1270 
1271 
1272 /*
1273  * __es_remove_extent - removes block range from extent status tree
1274  *
1275  * @inode - file containing range
1276  * @lblk - first block in range
1277  * @end - last block in range
1278  * @reserved - number of cluster reservations released
1279  *
1280  * If @reserved is not NULL and delayed allocation is enabled, counts
1281  * block/cluster reservations freed by removing range and if bigalloc
1282  * enabled cancels pending reservations as needed. Returns 0 on success,
1283  * error code on failure.
1284  */
1285 static int __es_remove_extent(struct inode *inode, ext4_lblk_t lblk,
1286                               ext4_lblk_t end, int *reserved)
1287 {
1288         struct ext4_es_tree *tree = &EXT4_I(inode)->i_es_tree;
1289         struct rb_node *node;
1290         struct extent_status *es;
1291         struct extent_status orig_es;
1292         ext4_lblk_t len1, len2;
1293         ext4_fsblk_t block;
1294         int err;
1295         bool count_reserved = true;
1296         struct rsvd_count rc;
1297 
1298         if (reserved == NULL || !test_opt(inode->i_sb, DELALLOC))
1299                 count_reserved = false;
1300 retry:
1301         err = 0;
1302 
1303         es = __es_tree_search(&tree->root, lblk);
1304         if (!es)
1305                 goto out;
1306         if (es->es_lblk > end)
1307                 goto out;
1308 
1309         /* Simply invalidate cache_es. */
1310         tree->cache_es = NULL;
1311         if (count_reserved)
1312                 init_rsvd(inode, lblk, es, &rc);
1313 
1314         orig_es.es_lblk = es->es_lblk;
1315         orig_es.es_len = es->es_len;
1316         orig_es.es_pblk = es->es_pblk;
1317 
1318         len1 = lblk > es->es_lblk ? lblk - es->es_lblk : 0;
1319         len2 = ext4_es_end(es) > end ? ext4_es_end(es) - end : 0;
1320         if (len1 > 0)
1321                 es->es_len = len1;
1322         if (len2 > 0) {
1323                 if (len1 > 0) {
1324                         struct extent_status newes;
1325 
1326                         newes.es_lblk = end + 1;
1327                         newes.es_len = len2;
1328                         block = 0x7FDEADBEEFULL;
1329                         if (ext4_es_is_written(&orig_es) ||
1330                             ext4_es_is_unwritten(&orig_es))
1331                                 block = ext4_es_pblock(&orig_es) +
1332                                         orig_es.es_len - len2;
1333                         ext4_es_store_pblock_status(&newes, block,
1334                                                     ext4_es_status(&orig_es));
1335                         err = __es_insert_extent(inode, &newes);
1336                         if (err) {
1337                                 es->es_lblk = orig_es.es_lblk;
1338                                 es->es_len = orig_es.es_len;
1339                                 if ((err == -ENOMEM) &&
1340                                     __es_shrink(EXT4_SB(inode->i_sb),
1341                                                         128, EXT4_I(inode)))
1342                                         goto retry;
1343                                 goto out;
1344                         }
1345                 } else {
1346                         es->es_lblk = end + 1;
1347                         es->es_len = len2;
1348                         if (ext4_es_is_written(es) ||
1349                             ext4_es_is_unwritten(es)) {
1350                                 block = orig_es.es_pblk + orig_es.es_len - len2;
1351                                 ext4_es_store_pblock(es, block);
1352                         }
1353                 }
1354                 if (count_reserved)
1355                         count_rsvd(inode, lblk, orig_es.es_len - len1 - len2,
1356                                    &orig_es, &rc);
1357                 goto out;
1358         }
1359 
1360         if (len1 > 0) {
1361                 if (count_reserved)
1362                         count_rsvd(inode, lblk, orig_es.es_len - len1,
1363                                    &orig_es, &rc);
1364                 node = rb_next(&es->rb_node);
1365                 if (node)
1366                         es = rb_entry(node, struct extent_status, rb_node);
1367                 else
1368                         es = NULL;
1369         }
1370 
1371         while (es && ext4_es_end(es) <= end) {
1372                 if (count_reserved)
1373                         count_rsvd(inode, es->es_lblk, es->es_len, es, &rc);
1374                 node = rb_next(&es->rb_node);
1375                 rb_erase(&es->rb_node, &tree->root);
1376                 ext4_es_free_extent(inode, es);
1377                 if (!node) {
1378                         es = NULL;
1379                         break;
1380                 }
1381                 es = rb_entry(node, struct extent_status, rb_node);
1382         }
1383 
1384         if (es && es->es_lblk < end + 1) {
1385                 ext4_lblk_t orig_len = es->es_len;
1386 
1387                 len1 = ext4_es_end(es) - end;
1388                 if (count_reserved)
1389                         count_rsvd(inode, es->es_lblk, orig_len - len1,
1390                                    es, &rc);
1391                 es->es_lblk = end + 1;
1392                 es->es_len = len1;
1393                 if (ext4_es_is_written(es) || ext4_es_is_unwritten(es)) {
1394                         block = es->es_pblk + orig_len - len1;
1395                         ext4_es_store_pblock(es, block);
1396                 }
1397         }
1398 
1399         if (count_reserved)
1400                 *reserved = get_rsvd(inode, end, es, &rc);
1401 out:
1402         return err;
1403 }
1404 
1405 /*
1406  * ext4_es_remove_extent - removes block range from extent status tree
1407  *
1408  * @inode - file containing range
1409  * @lblk - first block in range
1410  * @len - number of blocks to remove
1411  *
1412  * Reduces block/cluster reservation count and for bigalloc cancels pending
1413  * reservations as needed. Returns 0 on success, error code on failure.
1414  */
1415 int ext4_es_remove_extent(struct inode *inode, ext4_lblk_t lblk,
1416                           ext4_lblk_t len)
1417 {
1418         ext4_lblk_t end;
1419         int err = 0;
1420         int reserved = 0;
1421 
1422         trace_ext4_es_remove_extent(inode, lblk, len);
1423         es_debug("remove [%u/%u) from extent status tree of inode %lu\n",
1424                  lblk, len, inode->i_ino);
1425 
1426         if (!len)
1427                 return err;
1428 
1429         end = lblk + len - 1;
1430         BUG_ON(end < lblk);
1431 
1432         /*
1433          * ext4_clear_inode() depends on us taking i_es_lock unconditionally
1434          * so that we are sure __es_shrink() is done with the inode before it
1435          * is reclaimed.
1436          */
1437         write_lock(&EXT4_I(inode)->i_es_lock);
1438         err = __es_remove_extent(inode, lblk, end, &reserved);
1439         write_unlock(&EXT4_I(inode)->i_es_lock);
1440         ext4_es_print_tree(inode);
1441         ext4_da_release_space(inode, reserved);
1442         return err;
1443 }
1444 
1445 static int __es_shrink(struct ext4_sb_info *sbi, int nr_to_scan,
1446                        struct ext4_inode_info *locked_ei)
1447 {
1448         struct ext4_inode_info *ei;
1449         struct ext4_es_stats *es_stats;
1450         ktime_t start_time;
1451         u64 scan_time;
1452         int nr_to_walk;
1453         int nr_shrunk = 0;
1454         int retried = 0, nr_skipped = 0;
1455 
1456         es_stats = &sbi->s_es_stats;
1457         start_time = ktime_get();
1458 
1459 retry:
1460         spin_lock(&sbi->s_es_lock);
1461         nr_to_walk = sbi->s_es_nr_inode;
1462         while (nr_to_walk-- > 0) {
1463                 if (list_empty(&sbi->s_es_list)) {
1464                         spin_unlock(&sbi->s_es_lock);
1465                         goto out;
1466                 }
1467                 ei = list_first_entry(&sbi->s_es_list, struct ext4_inode_info,
1468                                       i_es_list);
1469                 /* Move the inode to the tail */
1470                 list_move_tail(&ei->i_es_list, &sbi->s_es_list);
1471 
1472                 /*
1473                  * Normally we try hard to avoid shrinking precached inodes,
1474                  * but we will as a last resort.
1475                  */
1476                 if (!retried && ext4_test_inode_state(&ei->vfs_inode,
1477                                                 EXT4_STATE_EXT_PRECACHED)) {
1478                         nr_skipped++;
1479                         continue;
1480                 }
1481 
1482                 if (ei == locked_ei || !write_trylock(&ei->i_es_lock)) {
1483                         nr_skipped++;
1484                         continue;
1485                 }
1486                 /*
1487                  * Now we hold i_es_lock which protects us from inode reclaim
1488                  * freeing inode under us
1489                  */
1490                 spin_unlock(&sbi->s_es_lock);
1491 
1492                 nr_shrunk += es_reclaim_extents(ei, &nr_to_scan);
1493                 write_unlock(&ei->i_es_lock);
1494 
1495                 if (nr_to_scan <= 0)
1496                         goto out;
1497                 spin_lock(&sbi->s_es_lock);
1498         }
1499         spin_unlock(&sbi->s_es_lock);
1500 
1501         /*
1502          * If we skipped any inodes, and we weren't able to make any
1503          * forward progress, try again to scan precached inodes.
1504          */
1505         if ((nr_shrunk == 0) && nr_skipped && !retried) {
1506                 retried++;
1507                 goto retry;
1508         }
1509 
1510         if (locked_ei && nr_shrunk == 0)
1511                 nr_shrunk = es_reclaim_extents(locked_ei, &nr_to_scan);
1512 
1513 out:
1514         scan_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1515         if (likely(es_stats->es_stats_scan_time))
1516                 es_stats->es_stats_scan_time = (scan_time +
1517                                 es_stats->es_stats_scan_time*3) / 4;
1518         else
1519                 es_stats->es_stats_scan_time = scan_time;
1520         if (scan_time > es_stats->es_stats_max_scan_time)
1521                 es_stats->es_stats_max_scan_time = scan_time;
1522         if (likely(es_stats->es_stats_shrunk))
1523                 es_stats->es_stats_shrunk = (nr_shrunk +
1524                                 es_stats->es_stats_shrunk*3) / 4;
1525         else
1526                 es_stats->es_stats_shrunk = nr_shrunk;
1527 
1528         trace_ext4_es_shrink(sbi->s_sb, nr_shrunk, scan_time,
1529                              nr_skipped, retried);
1530         return nr_shrunk;
1531 }
1532 
1533 static unsigned long ext4_es_count(struct shrinker *shrink,
1534                                    struct shrink_control *sc)
1535 {
1536         unsigned long nr;
1537         struct ext4_sb_info *sbi;
1538 
1539         sbi = container_of(shrink, struct ext4_sb_info, s_es_shrinker);
1540         nr = percpu_counter_read_positive(&sbi->s_es_stats.es_stats_shk_cnt);
1541         trace_ext4_es_shrink_count(sbi->s_sb, sc->nr_to_scan, nr);
1542         return nr;
1543 }
1544 
1545 static unsigned long ext4_es_scan(struct shrinker *shrink,
1546                                   struct shrink_control *sc)
1547 {
1548         struct ext4_sb_info *sbi = container_of(shrink,
1549                                         struct ext4_sb_info, s_es_shrinker);
1550         int nr_to_scan = sc->nr_to_scan;
1551         int ret, nr_shrunk;
1552 
1553         ret = percpu_counter_read_positive(&sbi->s_es_stats.es_stats_shk_cnt);
1554         trace_ext4_es_shrink_scan_enter(sbi->s_sb, nr_to_scan, ret);
1555 
1556         if (!nr_to_scan)
1557                 return ret;
1558 
1559         nr_shrunk = __es_shrink(sbi, nr_to_scan, NULL);
1560 
1561         trace_ext4_es_shrink_scan_exit(sbi->s_sb, nr_shrunk, ret);
1562         return nr_shrunk;
1563 }
1564 
1565 int ext4_seq_es_shrinker_info_show(struct seq_file *seq, void *v)
1566 {
1567         struct ext4_sb_info *sbi = EXT4_SB((struct super_block *) seq->private);
1568         struct ext4_es_stats *es_stats = &sbi->s_es_stats;
1569         struct ext4_inode_info *ei, *max = NULL;
1570         unsigned int inode_cnt = 0;
1571 
1572         if (v != SEQ_START_TOKEN)
1573                 return 0;
1574 
1575         /* here we just find an inode that has the max nr. of objects */
1576         spin_lock(&sbi->s_es_lock);
1577         list_for_each_entry(ei, &sbi->s_es_list, i_es_list) {
1578                 inode_cnt++;
1579                 if (max && max->i_es_all_nr < ei->i_es_all_nr)
1580                         max = ei;
1581                 else if (!max)
1582                         max = ei;
1583         }
1584         spin_unlock(&sbi->s_es_lock);
1585 
1586         seq_printf(seq, "stats:\n  %lld objects\n  %lld reclaimable objects\n",
1587                    percpu_counter_sum_positive(&es_stats->es_stats_all_cnt),
1588                    percpu_counter_sum_positive(&es_stats->es_stats_shk_cnt));
1589         seq_printf(seq, "  %lld/%lld cache hits/misses\n",
1590                    percpu_counter_sum_positive(&es_stats->es_stats_cache_hits),
1591                    percpu_counter_sum_positive(&es_stats->es_stats_cache_misses));
1592         if (inode_cnt)
1593                 seq_printf(seq, "  %d inodes on list\n", inode_cnt);
1594 
1595         seq_printf(seq, "average:\n  %llu us scan time\n",
1596             div_u64(es_stats->es_stats_scan_time, 1000));
1597         seq_printf(seq, "  %lu shrunk objects\n", es_stats->es_stats_shrunk);
1598         if (inode_cnt)
1599                 seq_printf(seq,
1600                     "maximum:\n  %lu inode (%u objects, %u reclaimable)\n"
1601                     "  %llu us max scan time\n",
1602                     max->vfs_inode.i_ino, max->i_es_all_nr, max->i_es_shk_nr,
1603                     div_u64(es_stats->es_stats_max_scan_time, 1000));
1604 
1605         return 0;
1606 }
1607 
1608 int ext4_es_register_shrinker(struct ext4_sb_info *sbi)
1609 {
1610         int err;
1611 
1612         /* Make sure we have enough bits for physical block number */
1613         BUILD_BUG_ON(ES_SHIFT < 48);
1614         INIT_LIST_HEAD(&sbi->s_es_list);
1615         sbi->s_es_nr_inode = 0;
1616         spin_lock_init(&sbi->s_es_lock);
1617         sbi->s_es_stats.es_stats_shrunk = 0;
1618         err = percpu_counter_init(&sbi->s_es_stats.es_stats_cache_hits, 0,
1619                                   GFP_KERNEL);
1620         if (err)
1621                 return err;
1622         err = percpu_counter_init(&sbi->s_es_stats.es_stats_cache_misses, 0,
1623                                   GFP_KERNEL);
1624         if (err)
1625                 goto err1;
1626         sbi->s_es_stats.es_stats_scan_time = 0;
1627         sbi->s_es_stats.es_stats_max_scan_time = 0;
1628         err = percpu_counter_init(&sbi->s_es_stats.es_stats_all_cnt, 0, GFP_KERNEL);
1629         if (err)
1630                 goto err2;
1631         err = percpu_counter_init(&sbi->s_es_stats.es_stats_shk_cnt, 0, GFP_KERNEL);
1632         if (err)
1633                 goto err3;
1634 
1635         sbi->s_es_shrinker.scan_objects = ext4_es_scan;
1636         sbi->s_es_shrinker.count_objects = ext4_es_count;
1637         sbi->s_es_shrinker.seeks = DEFAULT_SEEKS;
1638         err = register_shrinker(&sbi->s_es_shrinker);
1639         if (err)
1640                 goto err4;
1641 
1642         return 0;
1643 err4:
1644         percpu_counter_destroy(&sbi->s_es_stats.es_stats_shk_cnt);
1645 err3:
1646         percpu_counter_destroy(&sbi->s_es_stats.es_stats_all_cnt);
1647 err2:
1648         percpu_counter_destroy(&sbi->s_es_stats.es_stats_cache_misses);
1649 err1:
1650         percpu_counter_destroy(&sbi->s_es_stats.es_stats_cache_hits);
1651         return err;
1652 }
1653 
1654 void ext4_es_unregister_shrinker(struct ext4_sb_info *sbi)
1655 {
1656         percpu_counter_destroy(&sbi->s_es_stats.es_stats_cache_hits);
1657         percpu_counter_destroy(&sbi->s_es_stats.es_stats_cache_misses);
1658         percpu_counter_destroy(&sbi->s_es_stats.es_stats_all_cnt);
1659         percpu_counter_destroy(&sbi->s_es_stats.es_stats_shk_cnt);
1660         unregister_shrinker(&sbi->s_es_shrinker);
1661 }
1662 
1663 /*
1664  * Shrink extents in given inode from ei->i_es_shrink_lblk till end. Scan at
1665  * most *nr_to_scan extents, update *nr_to_scan accordingly.
1666  *
1667  * Return 0 if we hit end of tree / interval, 1 if we exhausted nr_to_scan.
1668  * Increment *nr_shrunk by the number of reclaimed extents. Also update
1669  * ei->i_es_shrink_lblk to where we should continue scanning.
1670  */
1671 static int es_do_reclaim_extents(struct ext4_inode_info *ei, ext4_lblk_t end,
1672                                  int *nr_to_scan, int *nr_shrunk)
1673 {
1674         struct inode *inode = &ei->vfs_inode;
1675         struct ext4_es_tree *tree = &ei->i_es_tree;
1676         struct extent_status *es;
1677         struct rb_node *node;
1678 
1679         es = __es_tree_search(&tree->root, ei->i_es_shrink_lblk);
1680         if (!es)
1681                 goto out_wrap;
1682 
1683         while (*nr_to_scan > 0) {
1684                 if (es->es_lblk > end) {
1685                         ei->i_es_shrink_lblk = end + 1;
1686                         return 0;
1687                 }
1688 
1689                 (*nr_to_scan)--;
1690                 node = rb_next(&es->rb_node);
1691                 /*
1692                  * We can't reclaim delayed extent from status tree because
1693                  * fiemap, bigallic, and seek_data/hole need to use it.
1694                  */
1695                 if (ext4_es_is_delayed(es))
1696                         goto next;
1697                 if (ext4_es_is_referenced(es)) {
1698                         ext4_es_clear_referenced(es);
1699                         goto next;
1700                 }
1701 
1702                 rb_erase(&es->rb_node, &tree->root);
1703                 ext4_es_free_extent(inode, es);
1704                 (*nr_shrunk)++;
1705 next:
1706                 if (!node)
1707                         goto out_wrap;
1708                 es = rb_entry(node, struct extent_status, rb_node);
1709         }
1710         ei->i_es_shrink_lblk = es->es_lblk;
1711         return 1;
1712 out_wrap:
1713         ei->i_es_shrink_lblk = 0;
1714         return 0;
1715 }
1716 
1717 static int es_reclaim_extents(struct ext4_inode_info *ei, int *nr_to_scan)
1718 {
1719         struct inode *inode = &ei->vfs_inode;
1720         int nr_shrunk = 0;
1721         ext4_lblk_t start = ei->i_es_shrink_lblk;
1722         static DEFINE_RATELIMIT_STATE(_rs, DEFAULT_RATELIMIT_INTERVAL,
1723                                       DEFAULT_RATELIMIT_BURST);
1724 
1725         if (ei->i_es_shk_nr == 0)
1726                 return 0;
1727 
1728         if (ext4_test_inode_state(inode, EXT4_STATE_EXT_PRECACHED) &&
1729             __ratelimit(&_rs))
1730                 ext4_warning(inode->i_sb, "forced shrink of precached extents");
1731 
1732         if (!es_do_reclaim_extents(ei, EXT_MAX_BLOCKS, nr_to_scan, &nr_shrunk) &&
1733             start != 0)
1734                 es_do_reclaim_extents(ei, start - 1, nr_to_scan, &nr_shrunk);
1735 
1736         ei->i_es_tree.cache_es = NULL;
1737         return nr_shrunk;
1738 }
1739 
1740 /*
1741  * Called to support EXT4_IOC_CLEAR_ES_CACHE.  We can only remove
1742  * discretionary entries from the extent status cache.  (Some entries
1743  * must be present for proper operations.)
1744  */
1745 void ext4_clear_inode_es(struct inode *inode)
1746 {
1747         struct ext4_inode_info *ei = EXT4_I(inode);
1748         struct extent_status *es;
1749         struct ext4_es_tree *tree;
1750         struct rb_node *node;
1751 
1752         write_lock(&ei->i_es_lock);
1753         tree = &EXT4_I(inode)->i_es_tree;
1754         tree->cache_es = NULL;
1755         node = rb_first(&tree->root);
1756         while (node) {
1757                 es = rb_entry(node, struct extent_status, rb_node);
1758                 node = rb_next(node);
1759                 if (!ext4_es_is_delayed(es)) {
1760                         rb_erase(&es->rb_node, &tree->root);
1761                         ext4_es_free_extent(inode, es);
1762                 }
1763         }
1764         ext4_clear_inode_state(inode, EXT4_STATE_EXT_PRECACHED);
1765         write_unlock(&ei->i_es_lock);
1766 }
1767 
1768 #ifdef ES_DEBUG__
1769 static void ext4_print_pending_tree(struct inode *inode)
1770 {
1771         struct ext4_pending_tree *tree;
1772         struct rb_node *node;
1773         struct pending_reservation *pr;
1774 
1775         printk(KERN_DEBUG "pending reservations for inode %lu:", inode->i_ino);
1776         tree = &EXT4_I(inode)->i_pending_tree;
1777         node = rb_first(&tree->root);
1778         while (node) {
1779                 pr = rb_entry(node, struct pending_reservation, rb_node);
1780                 printk(KERN_DEBUG " %u", pr->lclu);
1781                 node = rb_next(node);
1782         }
1783         printk(KERN_DEBUG "\n");
1784 }
1785 #else
1786 #define ext4_print_pending_tree(inode)
1787 #endif
1788 
1789 int __init ext4_init_pending(void)
1790 {
1791         ext4_pending_cachep = kmem_cache_create("ext4_pending_reservation",
1792                                            sizeof(struct pending_reservation),
1793                                            0, (SLAB_RECLAIM_ACCOUNT), NULL);
1794         if (ext4_pending_cachep == NULL)
1795                 return -ENOMEM;
1796         return 0;
1797 }
1798 
1799 void ext4_exit_pending(void)
1800 {
1801         kmem_cache_destroy(ext4_pending_cachep);
1802 }
1803 
1804 void ext4_init_pending_tree(struct ext4_pending_tree *tree)
1805 {
1806         tree->root = RB_ROOT;
1807 }
1808 
1809 /*
1810  * __get_pending - retrieve a pointer to a pending reservation
1811  *
1812  * @inode - file containing the pending cluster reservation
1813  * @lclu - logical cluster of interest
1814  *
1815  * Returns a pointer to a pending reservation if it's a member of
1816  * the set, and NULL if not.  Must be called holding i_es_lock.
1817  */
1818 static struct pending_reservation *__get_pending(struct inode *inode,
1819                                                  ext4_lblk_t lclu)
1820 {
1821         struct ext4_pending_tree *tree;
1822         struct rb_node *node;
1823         struct pending_reservation *pr = NULL;
1824 
1825         tree = &EXT4_I(inode)->i_pending_tree;
1826         node = (&tree->root)->rb_node;
1827 
1828         while (node) {
1829                 pr = rb_entry(node, struct pending_reservation, rb_node);
1830                 if (lclu < pr->lclu)
1831                         node = node->rb_left;
1832                 else if (lclu > pr->lclu)
1833                         node = node->rb_right;
1834                 else if (lclu == pr->lclu)
1835                         return pr;
1836         }
1837         return NULL;
1838 }
1839 
1840 /*
1841  * __insert_pending - adds a pending cluster reservation to the set of
1842  *                    pending reservations
1843  *
1844  * @inode - file containing the cluster
1845  * @lblk - logical block in the cluster to be added
1846  *
1847  * Returns 0 on successful insertion and -ENOMEM on failure.  If the
1848  * pending reservation is already in the set, returns successfully.
1849  */
1850 static int __insert_pending(struct inode *inode, ext4_lblk_t lblk)
1851 {
1852         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1853         struct ext4_pending_tree *tree = &EXT4_I(inode)->i_pending_tree;
1854         struct rb_node **p = &tree->root.rb_node;
1855         struct rb_node *parent = NULL;
1856         struct pending_reservation *pr;
1857         ext4_lblk_t lclu;
1858         int ret = 0;
1859 
1860         lclu = EXT4_B2C(sbi, lblk);
1861         /* search to find parent for insertion */
1862         while (*p) {
1863                 parent = *p;
1864                 pr = rb_entry(parent, struct pending_reservation, rb_node);
1865 
1866                 if (lclu < pr->lclu) {
1867                         p = &(*p)->rb_left;
1868                 } else if (lclu > pr->lclu) {
1869                         p = &(*p)->rb_right;
1870                 } else {
1871                         /* pending reservation already inserted */
1872                         goto out;
1873                 }
1874         }
1875 
1876         pr = kmem_cache_alloc(ext4_pending_cachep, GFP_ATOMIC);
1877         if (pr == NULL) {
1878                 ret = -ENOMEM;
1879                 goto out;
1880         }
1881         pr->lclu = lclu;
1882 
1883         rb_link_node(&pr->rb_node, parent, p);
1884         rb_insert_color(&pr->rb_node, &tree->root);
1885 
1886 out:
1887         return ret;
1888 }
1889 
1890 /*
1891  * __remove_pending - removes a pending cluster reservation from the set
1892  *                    of pending reservations
1893  *
1894  * @inode - file containing the cluster
1895  * @lblk - logical block in the pending cluster reservation to be removed
1896  *
1897  * Returns successfully if pending reservation is not a member of the set.
1898  */
1899 static void __remove_pending(struct inode *inode, ext4_lblk_t lblk)
1900 {
1901         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1902         struct pending_reservation *pr;
1903         struct ext4_pending_tree *tree;
1904 
1905         pr = __get_pending(inode, EXT4_B2C(sbi, lblk));
1906         if (pr != NULL) {
1907                 tree = &EXT4_I(inode)->i_pending_tree;
1908                 rb_erase(&pr->rb_node, &tree->root);
1909                 kmem_cache_free(ext4_pending_cachep, pr);
1910         }
1911 }
1912 
1913 /*
1914  * ext4_remove_pending - removes a pending cluster reservation from the set
1915  *                       of pending reservations
1916  *
1917  * @inode - file containing the cluster
1918  * @lblk - logical block in the pending cluster reservation to be removed
1919  *
1920  * Locking for external use of __remove_pending.
1921  */
1922 void ext4_remove_pending(struct inode *inode, ext4_lblk_t lblk)
1923 {
1924         struct ext4_inode_info *ei = EXT4_I(inode);
1925 
1926         write_lock(&ei->i_es_lock);
1927         __remove_pending(inode, lblk);
1928         write_unlock(&ei->i_es_lock);
1929 }
1930 
1931 /*
1932  * ext4_is_pending - determine whether a cluster has a pending reservation
1933  *                   on it
1934  *
1935  * @inode - file containing the cluster
1936  * @lblk - logical block in the cluster
1937  *
1938  * Returns true if there's a pending reservation for the cluster in the
1939  * set of pending reservations, and false if not.
1940  */
1941 bool ext4_is_pending(struct inode *inode, ext4_lblk_t lblk)
1942 {
1943         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1944         struct ext4_inode_info *ei = EXT4_I(inode);
1945         bool ret;
1946 
1947         read_lock(&ei->i_es_lock);
1948         ret = (bool)(__get_pending(inode, EXT4_B2C(sbi, lblk)) != NULL);
1949         read_unlock(&ei->i_es_lock);
1950 
1951         return ret;
1952 }
1953 
1954 /*
1955  * ext4_es_insert_delayed_block - adds a delayed block to the extents status
1956  *                                tree, adding a pending reservation where
1957  *                                needed
1958  *
1959  * @inode - file containing the newly added block
1960  * @lblk - logical block to be added
1961  * @allocated - indicates whether a physical cluster has been allocated for
1962  *              the logical cluster that contains the block
1963  *
1964  * Returns 0 on success, negative error code on failure.
1965  */
1966 int ext4_es_insert_delayed_block(struct inode *inode, ext4_lblk_t lblk,
1967                                  bool allocated)
1968 {
1969         struct extent_status newes;
1970         int err = 0;
1971 
1972         es_debug("add [%u/1) delayed to extent status tree of inode %lu\n",
1973                  lblk, inode->i_ino);
1974 
1975         newes.es_lblk = lblk;
1976         newes.es_len = 1;
1977         ext4_es_store_pblock_status(&newes, ~0, EXTENT_STATUS_DELAYED);
1978         trace_ext4_es_insert_delayed_block(inode, &newes, allocated);
1979 
1980         ext4_es_insert_extent_check(inode, &newes);
1981 
1982         write_lock(&EXT4_I(inode)->i_es_lock);
1983 
1984         err = __es_remove_extent(inode, lblk, lblk, NULL);
1985         if (err != 0)
1986                 goto error;
1987 retry:
1988         err = __es_insert_extent(inode, &newes);
1989         if (err == -ENOMEM && __es_shrink(EXT4_SB(inode->i_sb),
1990                                           128, EXT4_I(inode)))
1991                 goto retry;
1992         if (err != 0)
1993                 goto error;
1994 
1995         if (allocated)
1996                 __insert_pending(inode, lblk);
1997 
1998 error:
1999         write_unlock(&EXT4_I(inode)->i_es_lock);
2000 
2001         ext4_es_print_tree(inode);
2002         ext4_print_pending_tree(inode);
2003 
2004         return err;
2005 }
2006 
2007 /*
2008  * __es_delayed_clu - count number of clusters containing blocks that
2009  *                    are delayed only
2010  *
2011  * @inode - file containing block range
2012  * @start - logical block defining start of range
2013  * @end - logical block defining end of range
2014  *
2015  * Returns the number of clusters containing only delayed (not delayed
2016  * and unwritten) blocks in the range specified by @start and @end.  Any
2017  * cluster or part of a cluster within the range and containing a delayed
2018  * and not unwritten block within the range is counted as a whole cluster.
2019  */
2020 static unsigned int __es_delayed_clu(struct inode *inode, ext4_lblk_t start,
2021                                      ext4_lblk_t end)
2022 {
2023         struct ext4_es_tree *tree = &EXT4_I(inode)->i_es_tree;
2024         struct extent_status *es;
2025         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2026         struct rb_node *node;
2027         ext4_lblk_t first_lclu, last_lclu;
2028         unsigned long long last_counted_lclu;
2029         unsigned int n = 0;
2030 
2031         /* guaranteed to be unequal to any ext4_lblk_t value */
2032         last_counted_lclu = ~0ULL;
2033 
2034         es = __es_tree_search(&tree->root, start);
2035 
2036         while (es && (es->es_lblk <= end)) {
2037                 if (ext4_es_is_delonly(es)) {
2038                         if (es->es_lblk <= start)
2039                                 first_lclu = EXT4_B2C(sbi, start);
2040                         else
2041                                 first_lclu = EXT4_B2C(sbi, es->es_lblk);
2042 
2043                         if (ext4_es_end(es) >= end)
2044                                 last_lclu = EXT4_B2C(sbi, end);
2045                         else
2046                                 last_lclu = EXT4_B2C(sbi, ext4_es_end(es));
2047 
2048                         if (first_lclu == last_counted_lclu)
2049                                 n += last_lclu - first_lclu;
2050                         else
2051                                 n += last_lclu - first_lclu + 1;
2052                         last_counted_lclu = last_lclu;
2053                 }
2054                 node = rb_next(&es->rb_node);
2055                 if (!node)
2056                         break;
2057                 es = rb_entry(node, struct extent_status, rb_node);
2058         }
2059 
2060         return n;
2061 }
2062 
2063 /*
2064  * ext4_es_delayed_clu - count number of clusters containing blocks that
2065  *                       are both delayed and unwritten
2066  *
2067  * @inode - file containing block range
2068  * @lblk - logical block defining start of range
2069  * @len - number of blocks in range
2070  *
2071  * Locking for external use of __es_delayed_clu().
2072  */
2073 unsigned int ext4_es_delayed_clu(struct inode *inode, ext4_lblk_t lblk,
2074                                  ext4_lblk_t len)
2075 {
2076         struct ext4_inode_info *ei = EXT4_I(inode);
2077         ext4_lblk_t end;
2078         unsigned int n;
2079 
2080         if (len == 0)
2081                 return 0;
2082 
2083         end = lblk + len - 1;
2084         WARN_ON(end < lblk);
2085 
2086         read_lock(&ei->i_es_lock);
2087 
2088         n = __es_delayed_clu(inode, lblk, end);
2089 
2090         read_unlock(&ei->i_es_lock);
2091 
2092         return n;
2093 }
2094 
2095 /*
2096  * __revise_pending - makes, cancels, or leaves unchanged pending cluster
2097  *                    reservations for a specified block range depending
2098  *                    upon the presence or absence of delayed blocks
2099  *                    outside the range within clusters at the ends of the
2100  *                    range
2101  *
2102  * @inode - file containing the range
2103  * @lblk - logical block defining the start of range
2104  * @len  - length of range in blocks
2105  *
2106  * Used after a newly allocated extent is added to the extents status tree.
2107  * Requires that the extents in the range have either written or unwritten
2108  * status.  Must be called while holding i_es_lock.
2109  */
2110 static void __revise_pending(struct inode *inode, ext4_lblk_t lblk,
2111                              ext4_lblk_t len)
2112 {
2113         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2114         ext4_lblk_t end = lblk + len - 1;
2115         ext4_lblk_t first, last;
2116         bool f_del = false, l_del = false;
2117 
2118         if (len == 0)
2119                 return;
2120 
2121         /*
2122          * Two cases - block range within single cluster and block range
2123          * spanning two or more clusters.  Note that a cluster belonging
2124          * to a range starting and/or ending on a cluster boundary is treated
2125          * as if it does not contain a delayed extent.  The new range may
2126          * have allocated space for previously delayed blocks out to the
2127          * cluster boundary, requiring that any pre-existing pending
2128          * reservation be canceled.  Because this code only looks at blocks
2129          * outside the range, it should revise pending reservations
2130          * correctly even if the extent represented by the range can't be
2131          * inserted in the extents status tree due to ENOSPC.
2132          */
2133 
2134         if (EXT4_B2C(sbi, lblk) == EXT4_B2C(sbi, end)) {
2135                 first = EXT4_LBLK_CMASK(sbi, lblk);
2136                 if (first != lblk)
2137                         f_del = __es_scan_range(inode, &ext4_es_is_delonly,
2138                                                 first, lblk - 1);
2139                 if (f_del) {
2140                         __insert_pending(inode, first);
2141                 } else {
2142                         last = EXT4_LBLK_CMASK(sbi, end) +
2143                                sbi->s_cluster_ratio - 1;
2144                         if (last != end)
2145                                 l_del = __es_scan_range(inode,
2146                                                         &ext4_es_is_delonly,
2147                                                         end + 1, last);
2148                         if (l_del)
2149                                 __insert_pending(inode, last);
2150                         else
2151                                 __remove_pending(inode, last);
2152                 }
2153         } else {
2154                 first = EXT4_LBLK_CMASK(sbi, lblk);
2155                 if (first != lblk)
2156                         f_del = __es_scan_range(inode, &ext4_es_is_delonly,
2157                                                 first, lblk - 1);
2158                 if (f_del)
2159                         __insert_pending(inode, first);
2160                 else
2161                         __remove_pending(inode, first);
2162 
2163                 last = EXT4_LBLK_CMASK(sbi, end) + sbi->s_cluster_ratio - 1;
2164                 if (last != end)
2165                         l_del = __es_scan_range(inode, &ext4_es_is_delonly,
2166                                                 end + 1, last);
2167                 if (l_del)
2168                         __insert_pending(inode, last);
2169                 else
2170                         __remove_pending(inode, last);
2171         }
2172 }
/* [<][>][^][v][top][bottom][index][help] */
root/fs/ext4/extents_status.c

DEFINITIONS
