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ac27a0ec | 1 | /* |
617ba13b | 2 | * linux/fs/ext4/balloc.c |
ac27a0ec DK |
3 | * |
4 | * Copyright (C) 1992, 1993, 1994, 1995 | |
5 | * Remy Card (card@masi.ibp.fr) | |
6 | * Laboratoire MASI - Institut Blaise Pascal | |
7 | * Universite Pierre et Marie Curie (Paris VI) | |
8 | * | |
9 | * Enhanced block allocation by Stephen Tweedie (sct@redhat.com), 1993 | |
10 | * Big-endian to little-endian byte-swapping/bitmaps by | |
11 | * David S. Miller (davem@caip.rutgers.edu), 1995 | |
12 | */ | |
13 | ||
14 | #include <linux/time.h> | |
15 | #include <linux/capability.h> | |
16 | #include <linux/fs.h> | |
17 | #include <linux/jbd.h> | |
617ba13b MC |
18 | #include <linux/ext4_fs.h> |
19 | #include <linux/ext4_jbd.h> | |
ac27a0ec DK |
20 | #include <linux/quotaops.h> |
21 | #include <linux/buffer_head.h> | |
22 | ||
23 | /* | |
24 | * balloc.c contains the blocks allocation and deallocation routines | |
25 | */ | |
26 | ||
27 | /* | |
28 | * The free blocks are managed by bitmaps. A file system contains several | |
29 | * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap | |
30 | * block for inodes, N blocks for the inode table and data blocks. | |
31 | * | |
32 | * The file system contains group descriptors which are located after the | |
33 | * super block. Each descriptor contains the number of the bitmap block and | |
34 | * the free blocks count in the block. The descriptors are loaded in memory | |
617ba13b | 35 | * when a file system is mounted (see ext4_read_super). |
ac27a0ec DK |
36 | */ |
37 | ||
38 | ||
39 | #define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1) | |
40 | ||
41 | /** | |
617ba13b | 42 | * ext4_get_group_desc() -- load group descriptor from disk |
ac27a0ec DK |
43 | * @sb: super block |
44 | * @block_group: given block group | |
45 | * @bh: pointer to the buffer head to store the block | |
46 | * group descriptor | |
47 | */ | |
617ba13b | 48 | struct ext4_group_desc * ext4_get_group_desc(struct super_block * sb, |
ac27a0ec DK |
49 | unsigned int block_group, |
50 | struct buffer_head ** bh) | |
51 | { | |
52 | unsigned long group_desc; | |
53 | unsigned long offset; | |
617ba13b MC |
54 | struct ext4_group_desc * desc; |
55 | struct ext4_sb_info *sbi = EXT4_SB(sb); | |
ac27a0ec DK |
56 | |
57 | if (block_group >= sbi->s_groups_count) { | |
617ba13b | 58 | ext4_error (sb, "ext4_get_group_desc", |
ac27a0ec DK |
59 | "block_group >= groups_count - " |
60 | "block_group = %d, groups_count = %lu", | |
61 | block_group, sbi->s_groups_count); | |
62 | ||
63 | return NULL; | |
64 | } | |
65 | smp_rmb(); | |
66 | ||
617ba13b MC |
67 | group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb); |
68 | offset = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1); | |
ac27a0ec | 69 | if (!sbi->s_group_desc[group_desc]) { |
617ba13b | 70 | ext4_error (sb, "ext4_get_group_desc", |
ac27a0ec DK |
71 | "Group descriptor not loaded - " |
72 | "block_group = %d, group_desc = %lu, desc = %lu", | |
73 | block_group, group_desc, offset); | |
74 | return NULL; | |
75 | } | |
76 | ||
617ba13b | 77 | desc = (struct ext4_group_desc *) sbi->s_group_desc[group_desc]->b_data; |
ac27a0ec DK |
78 | if (bh) |
79 | *bh = sbi->s_group_desc[group_desc]; | |
80 | return desc + offset; | |
81 | } | |
82 | ||
83 | /** | |
84 | * read_block_bitmap() | |
85 | * @sb: super block | |
86 | * @block_group: given block group | |
87 | * | |
88 | * Read the bitmap for a given block_group, reading into the specified | |
89 | * slot in the superblock's bitmap cache. | |
90 | * | |
91 | * Return buffer_head on success or NULL in case of failure. | |
92 | */ | |
93 | static struct buffer_head * | |
94 | read_block_bitmap(struct super_block *sb, unsigned int block_group) | |
95 | { | |
617ba13b | 96 | struct ext4_group_desc * desc; |
ac27a0ec DK |
97 | struct buffer_head * bh = NULL; |
98 | ||
617ba13b | 99 | desc = ext4_get_group_desc (sb, block_group, NULL); |
ac27a0ec DK |
100 | if (!desc) |
101 | goto error_out; | |
102 | bh = sb_bread(sb, le32_to_cpu(desc->bg_block_bitmap)); | |
103 | if (!bh) | |
617ba13b | 104 | ext4_error (sb, "read_block_bitmap", |
ac27a0ec DK |
105 | "Cannot read block bitmap - " |
106 | "block_group = %d, block_bitmap = %u", | |
107 | block_group, le32_to_cpu(desc->bg_block_bitmap)); | |
108 | error_out: | |
109 | return bh; | |
110 | } | |
111 | /* | |
112 | * The reservation window structure operations | |
113 | * -------------------------------------------- | |
114 | * Operations include: | |
115 | * dump, find, add, remove, is_empty, find_next_reservable_window, etc. | |
116 | * | |
117 | * We use a red-black tree to represent per-filesystem reservation | |
118 | * windows. | |
119 | * | |
120 | */ | |
121 | ||
122 | /** | |
123 | * __rsv_window_dump() -- Dump the filesystem block allocation reservation map | |
124 | * @rb_root: root of per-filesystem reservation rb tree | |
125 | * @verbose: verbose mode | |
126 | * @fn: function which wishes to dump the reservation map | |
127 | * | |
128 | * If verbose is turned on, it will print the whole block reservation | |
129 | * windows(start, end). Otherwise, it will only print out the "bad" windows, | |
130 | * those windows that overlap with their immediate neighbors. | |
131 | */ | |
132 | #if 1 | |
133 | static void __rsv_window_dump(struct rb_root *root, int verbose, | |
134 | const char *fn) | |
135 | { | |
136 | struct rb_node *n; | |
617ba13b | 137 | struct ext4_reserve_window_node *rsv, *prev; |
ac27a0ec DK |
138 | int bad; |
139 | ||
140 | restart: | |
141 | n = rb_first(root); | |
142 | bad = 0; | |
143 | prev = NULL; | |
144 | ||
145 | printk("Block Allocation Reservation Windows Map (%s):\n", fn); | |
146 | while (n) { | |
617ba13b | 147 | rsv = list_entry(n, struct ext4_reserve_window_node, rsv_node); |
ac27a0ec DK |
148 | if (verbose) |
149 | printk("reservation window 0x%p " | |
150 | "start: %lu, end: %lu\n", | |
151 | rsv, rsv->rsv_start, rsv->rsv_end); | |
152 | if (rsv->rsv_start && rsv->rsv_start >= rsv->rsv_end) { | |
153 | printk("Bad reservation %p (start >= end)\n", | |
154 | rsv); | |
155 | bad = 1; | |
156 | } | |
157 | if (prev && prev->rsv_end >= rsv->rsv_start) { | |
158 | printk("Bad reservation %p (prev->end >= start)\n", | |
159 | rsv); | |
160 | bad = 1; | |
161 | } | |
162 | if (bad) { | |
163 | if (!verbose) { | |
164 | printk("Restarting reservation walk in verbose mode\n"); | |
165 | verbose = 1; | |
166 | goto restart; | |
167 | } | |
168 | } | |
169 | n = rb_next(n); | |
170 | prev = rsv; | |
171 | } | |
172 | printk("Window map complete.\n"); | |
173 | if (bad) | |
174 | BUG(); | |
175 | } | |
176 | #define rsv_window_dump(root, verbose) \ | |
177 | __rsv_window_dump((root), (verbose), __FUNCTION__) | |
178 | #else | |
179 | #define rsv_window_dump(root, verbose) do {} while (0) | |
180 | #endif | |
181 | ||
182 | /** | |
183 | * goal_in_my_reservation() | |
184 | * @rsv: inode's reservation window | |
185 | * @grp_goal: given goal block relative to the allocation block group | |
186 | * @group: the current allocation block group | |
187 | * @sb: filesystem super block | |
188 | * | |
189 | * Test if the given goal block (group relative) is within the file's | |
190 | * own block reservation window range. | |
191 | * | |
192 | * If the reservation window is outside the goal allocation group, return 0; | |
193 | * grp_goal (given goal block) could be -1, which means no specific | |
194 | * goal block. In this case, always return 1. | |
195 | * If the goal block is within the reservation window, return 1; | |
196 | * otherwise, return 0; | |
197 | */ | |
198 | static int | |
617ba13b | 199 | goal_in_my_reservation(struct ext4_reserve_window *rsv, ext4_grpblk_t grp_goal, |
ac27a0ec DK |
200 | unsigned int group, struct super_block * sb) |
201 | { | |
617ba13b | 202 | ext4_fsblk_t group_first_block, group_last_block; |
ac27a0ec | 203 | |
617ba13b MC |
204 | group_first_block = ext4_group_first_block_no(sb, group); |
205 | group_last_block = group_first_block + (EXT4_BLOCKS_PER_GROUP(sb) - 1); | |
ac27a0ec DK |
206 | |
207 | if ((rsv->_rsv_start > group_last_block) || | |
208 | (rsv->_rsv_end < group_first_block)) | |
209 | return 0; | |
210 | if ((grp_goal >= 0) && ((grp_goal + group_first_block < rsv->_rsv_start) | |
211 | || (grp_goal + group_first_block > rsv->_rsv_end))) | |
212 | return 0; | |
213 | return 1; | |
214 | } | |
215 | ||
216 | /** | |
217 | * search_reserve_window() | |
218 | * @rb_root: root of reservation tree | |
219 | * @goal: target allocation block | |
220 | * | |
221 | * Find the reserved window which includes the goal, or the previous one | |
222 | * if the goal is not in any window. | |
223 | * Returns NULL if there are no windows or if all windows start after the goal. | |
224 | */ | |
617ba13b MC |
225 | static struct ext4_reserve_window_node * |
226 | search_reserve_window(struct rb_root *root, ext4_fsblk_t goal) | |
ac27a0ec DK |
227 | { |
228 | struct rb_node *n = root->rb_node; | |
617ba13b | 229 | struct ext4_reserve_window_node *rsv; |
ac27a0ec DK |
230 | |
231 | if (!n) | |
232 | return NULL; | |
233 | ||
234 | do { | |
617ba13b | 235 | rsv = rb_entry(n, struct ext4_reserve_window_node, rsv_node); |
ac27a0ec DK |
236 | |
237 | if (goal < rsv->rsv_start) | |
238 | n = n->rb_left; | |
239 | else if (goal > rsv->rsv_end) | |
240 | n = n->rb_right; | |
241 | else | |
242 | return rsv; | |
243 | } while (n); | |
244 | /* | |
245 | * We've fallen off the end of the tree: the goal wasn't inside | |
246 | * any particular node. OK, the previous node must be to one | |
247 | * side of the interval containing the goal. If it's the RHS, | |
248 | * we need to back up one. | |
249 | */ | |
250 | if (rsv->rsv_start > goal) { | |
251 | n = rb_prev(&rsv->rsv_node); | |
617ba13b | 252 | rsv = rb_entry(n, struct ext4_reserve_window_node, rsv_node); |
ac27a0ec DK |
253 | } |
254 | return rsv; | |
255 | } | |
256 | ||
257 | /** | |
617ba13b | 258 | * ext4_rsv_window_add() -- Insert a window to the block reservation rb tree. |
ac27a0ec DK |
259 | * @sb: super block |
260 | * @rsv: reservation window to add | |
261 | * | |
262 | * Must be called with rsv_lock hold. | |
263 | */ | |
617ba13b MC |
264 | void ext4_rsv_window_add(struct super_block *sb, |
265 | struct ext4_reserve_window_node *rsv) | |
ac27a0ec | 266 | { |
617ba13b | 267 | struct rb_root *root = &EXT4_SB(sb)->s_rsv_window_root; |
ac27a0ec | 268 | struct rb_node *node = &rsv->rsv_node; |
617ba13b | 269 | ext4_fsblk_t start = rsv->rsv_start; |
ac27a0ec DK |
270 | |
271 | struct rb_node ** p = &root->rb_node; | |
272 | struct rb_node * parent = NULL; | |
617ba13b | 273 | struct ext4_reserve_window_node *this; |
ac27a0ec DK |
274 | |
275 | while (*p) | |
276 | { | |
277 | parent = *p; | |
617ba13b | 278 | this = rb_entry(parent, struct ext4_reserve_window_node, rsv_node); |
ac27a0ec DK |
279 | |
280 | if (start < this->rsv_start) | |
281 | p = &(*p)->rb_left; | |
282 | else if (start > this->rsv_end) | |
283 | p = &(*p)->rb_right; | |
284 | else { | |
285 | rsv_window_dump(root, 1); | |
286 | BUG(); | |
287 | } | |
288 | } | |
289 | ||
290 | rb_link_node(node, parent, p); | |
291 | rb_insert_color(node, root); | |
292 | } | |
293 | ||
294 | /** | |
617ba13b | 295 | * ext4_rsv_window_remove() -- unlink a window from the reservation rb tree |
ac27a0ec DK |
296 | * @sb: super block |
297 | * @rsv: reservation window to remove | |
298 | * | |
299 | * Mark the block reservation window as not allocated, and unlink it | |
300 | * from the filesystem reservation window rb tree. Must be called with | |
301 | * rsv_lock hold. | |
302 | */ | |
303 | static void rsv_window_remove(struct super_block *sb, | |
617ba13b | 304 | struct ext4_reserve_window_node *rsv) |
ac27a0ec | 305 | { |
617ba13b MC |
306 | rsv->rsv_start = EXT4_RESERVE_WINDOW_NOT_ALLOCATED; |
307 | rsv->rsv_end = EXT4_RESERVE_WINDOW_NOT_ALLOCATED; | |
ac27a0ec | 308 | rsv->rsv_alloc_hit = 0; |
617ba13b | 309 | rb_erase(&rsv->rsv_node, &EXT4_SB(sb)->s_rsv_window_root); |
ac27a0ec DK |
310 | } |
311 | ||
312 | /* | |
313 | * rsv_is_empty() -- Check if the reservation window is allocated. | |
314 | * @rsv: given reservation window to check | |
315 | * | |
617ba13b | 316 | * returns 1 if the end block is EXT4_RESERVE_WINDOW_NOT_ALLOCATED. |
ac27a0ec | 317 | */ |
617ba13b | 318 | static inline int rsv_is_empty(struct ext4_reserve_window *rsv) |
ac27a0ec DK |
319 | { |
320 | /* a valid reservation end block could not be 0 */ | |
617ba13b | 321 | return rsv->_rsv_end == EXT4_RESERVE_WINDOW_NOT_ALLOCATED; |
ac27a0ec DK |
322 | } |
323 | ||
324 | /** | |
617ba13b | 325 | * ext4_init_block_alloc_info() |
ac27a0ec DK |
326 | * @inode: file inode structure |
327 | * | |
328 | * Allocate and initialize the reservation window structure, and | |
617ba13b | 329 | * link the window to the ext4 inode structure at last |
ac27a0ec DK |
330 | * |
331 | * The reservation window structure is only dynamically allocated | |
617ba13b MC |
332 | * and linked to ext4 inode the first time the open file |
333 | * needs a new block. So, before every ext4_new_block(s) call, for | |
ac27a0ec DK |
334 | * regular files, we should check whether the reservation window |
335 | * structure exists or not. In the latter case, this function is called. | |
336 | * Fail to do so will result in block reservation being turned off for that | |
337 | * open file. | |
338 | * | |
617ba13b | 339 | * This function is called from ext4_get_blocks_handle(), also called |
ac27a0ec DK |
340 | * when setting the reservation window size through ioctl before the file |
341 | * is open for write (needs block allocation). | |
342 | * | |
343 | * Needs truncate_mutex protection prior to call this function. | |
344 | */ | |
617ba13b | 345 | void ext4_init_block_alloc_info(struct inode *inode) |
ac27a0ec | 346 | { |
617ba13b MC |
347 | struct ext4_inode_info *ei = EXT4_I(inode); |
348 | struct ext4_block_alloc_info *block_i = ei->i_block_alloc_info; | |
ac27a0ec DK |
349 | struct super_block *sb = inode->i_sb; |
350 | ||
351 | block_i = kmalloc(sizeof(*block_i), GFP_NOFS); | |
352 | if (block_i) { | |
617ba13b | 353 | struct ext4_reserve_window_node *rsv = &block_i->rsv_window_node; |
ac27a0ec | 354 | |
617ba13b MC |
355 | rsv->rsv_start = EXT4_RESERVE_WINDOW_NOT_ALLOCATED; |
356 | rsv->rsv_end = EXT4_RESERVE_WINDOW_NOT_ALLOCATED; | |
ac27a0ec DK |
357 | |
358 | /* | |
359 | * if filesystem is mounted with NORESERVATION, the goal | |
360 | * reservation window size is set to zero to indicate | |
361 | * block reservation is off | |
362 | */ | |
363 | if (!test_opt(sb, RESERVATION)) | |
364 | rsv->rsv_goal_size = 0; | |
365 | else | |
617ba13b | 366 | rsv->rsv_goal_size = EXT4_DEFAULT_RESERVE_BLOCKS; |
ac27a0ec DK |
367 | rsv->rsv_alloc_hit = 0; |
368 | block_i->last_alloc_logical_block = 0; | |
369 | block_i->last_alloc_physical_block = 0; | |
370 | } | |
371 | ei->i_block_alloc_info = block_i; | |
372 | } | |
373 | ||
374 | /** | |
617ba13b | 375 | * ext4_discard_reservation() |
ac27a0ec DK |
376 | * @inode: inode |
377 | * | |
378 | * Discard(free) block reservation window on last file close, or truncate | |
379 | * or at last iput(). | |
380 | * | |
381 | * It is being called in three cases: | |
617ba13b MC |
382 | * ext4_release_file(): last writer close the file |
383 | * ext4_clear_inode(): last iput(), when nobody link to this file. | |
384 | * ext4_truncate(): when the block indirect map is about to change. | |
ac27a0ec DK |
385 | * |
386 | */ | |
617ba13b | 387 | void ext4_discard_reservation(struct inode *inode) |
ac27a0ec | 388 | { |
617ba13b MC |
389 | struct ext4_inode_info *ei = EXT4_I(inode); |
390 | struct ext4_block_alloc_info *block_i = ei->i_block_alloc_info; | |
391 | struct ext4_reserve_window_node *rsv; | |
392 | spinlock_t *rsv_lock = &EXT4_SB(inode->i_sb)->s_rsv_window_lock; | |
ac27a0ec DK |
393 | |
394 | if (!block_i) | |
395 | return; | |
396 | ||
397 | rsv = &block_i->rsv_window_node; | |
398 | if (!rsv_is_empty(&rsv->rsv_window)) { | |
399 | spin_lock(rsv_lock); | |
400 | if (!rsv_is_empty(&rsv->rsv_window)) | |
401 | rsv_window_remove(inode->i_sb, rsv); | |
402 | spin_unlock(rsv_lock); | |
403 | } | |
404 | } | |
405 | ||
406 | /** | |
617ba13b | 407 | * ext4_free_blocks_sb() -- Free given blocks and update quota |
ac27a0ec DK |
408 | * @handle: handle to this transaction |
409 | * @sb: super block | |
410 | * @block: start physcial block to free | |
411 | * @count: number of blocks to free | |
412 | * @pdquot_freed_blocks: pointer to quota | |
413 | */ | |
617ba13b MC |
414 | void ext4_free_blocks_sb(handle_t *handle, struct super_block *sb, |
415 | ext4_fsblk_t block, unsigned long count, | |
ac27a0ec DK |
416 | unsigned long *pdquot_freed_blocks) |
417 | { | |
418 | struct buffer_head *bitmap_bh = NULL; | |
419 | struct buffer_head *gd_bh; | |
420 | unsigned long block_group; | |
617ba13b | 421 | ext4_grpblk_t bit; |
ac27a0ec DK |
422 | unsigned long i; |
423 | unsigned long overflow; | |
617ba13b MC |
424 | struct ext4_group_desc * desc; |
425 | struct ext4_super_block * es; | |
426 | struct ext4_sb_info *sbi; | |
ac27a0ec | 427 | int err = 0, ret; |
617ba13b | 428 | ext4_grpblk_t group_freed; |
ac27a0ec DK |
429 | |
430 | *pdquot_freed_blocks = 0; | |
617ba13b | 431 | sbi = EXT4_SB(sb); |
ac27a0ec DK |
432 | es = sbi->s_es; |
433 | if (block < le32_to_cpu(es->s_first_data_block) || | |
434 | block + count < block || | |
435 | block + count > le32_to_cpu(es->s_blocks_count)) { | |
617ba13b | 436 | ext4_error (sb, "ext4_free_blocks", |
ac27a0ec DK |
437 | "Freeing blocks not in datazone - " |
438 | "block = "E3FSBLK", count = %lu", block, count); | |
439 | goto error_return; | |
440 | } | |
441 | ||
617ba13b | 442 | ext4_debug ("freeing block(s) %lu-%lu\n", block, block + count - 1); |
ac27a0ec DK |
443 | |
444 | do_more: | |
445 | overflow = 0; | |
446 | block_group = (block - le32_to_cpu(es->s_first_data_block)) / | |
617ba13b | 447 | EXT4_BLOCKS_PER_GROUP(sb); |
ac27a0ec | 448 | bit = (block - le32_to_cpu(es->s_first_data_block)) % |
617ba13b | 449 | EXT4_BLOCKS_PER_GROUP(sb); |
ac27a0ec DK |
450 | /* |
451 | * Check to see if we are freeing blocks across a group | |
452 | * boundary. | |
453 | */ | |
617ba13b MC |
454 | if (bit + count > EXT4_BLOCKS_PER_GROUP(sb)) { |
455 | overflow = bit + count - EXT4_BLOCKS_PER_GROUP(sb); | |
ac27a0ec DK |
456 | count -= overflow; |
457 | } | |
458 | brelse(bitmap_bh); | |
459 | bitmap_bh = read_block_bitmap(sb, block_group); | |
460 | if (!bitmap_bh) | |
461 | goto error_return; | |
617ba13b | 462 | desc = ext4_get_group_desc (sb, block_group, &gd_bh); |
ac27a0ec DK |
463 | if (!desc) |
464 | goto error_return; | |
465 | ||
466 | if (in_range (le32_to_cpu(desc->bg_block_bitmap), block, count) || | |
467 | in_range (le32_to_cpu(desc->bg_inode_bitmap), block, count) || | |
468 | in_range (block, le32_to_cpu(desc->bg_inode_table), | |
469 | sbi->s_itb_per_group) || | |
470 | in_range (block + count - 1, le32_to_cpu(desc->bg_inode_table), | |
471 | sbi->s_itb_per_group)) | |
617ba13b | 472 | ext4_error (sb, "ext4_free_blocks", |
ac27a0ec DK |
473 | "Freeing blocks in system zones - " |
474 | "Block = "E3FSBLK", count = %lu", | |
475 | block, count); | |
476 | ||
477 | /* | |
478 | * We are about to start releasing blocks in the bitmap, | |
479 | * so we need undo access. | |
480 | */ | |
481 | /* @@@ check errors */ | |
482 | BUFFER_TRACE(bitmap_bh, "getting undo access"); | |
617ba13b | 483 | err = ext4_journal_get_undo_access(handle, bitmap_bh); |
ac27a0ec DK |
484 | if (err) |
485 | goto error_return; | |
486 | ||
487 | /* | |
488 | * We are about to modify some metadata. Call the journal APIs | |
489 | * to unshare ->b_data if a currently-committing transaction is | |
490 | * using it | |
491 | */ | |
492 | BUFFER_TRACE(gd_bh, "get_write_access"); | |
617ba13b | 493 | err = ext4_journal_get_write_access(handle, gd_bh); |
ac27a0ec DK |
494 | if (err) |
495 | goto error_return; | |
496 | ||
497 | jbd_lock_bh_state(bitmap_bh); | |
498 | ||
499 | for (i = 0, group_freed = 0; i < count; i++) { | |
500 | /* | |
501 | * An HJ special. This is expensive... | |
502 | */ | |
503 | #ifdef CONFIG_JBD_DEBUG | |
504 | jbd_unlock_bh_state(bitmap_bh); | |
505 | { | |
506 | struct buffer_head *debug_bh; | |
507 | debug_bh = sb_find_get_block(sb, block + i); | |
508 | if (debug_bh) { | |
509 | BUFFER_TRACE(debug_bh, "Deleted!"); | |
510 | if (!bh2jh(bitmap_bh)->b_committed_data) | |
511 | BUFFER_TRACE(debug_bh, | |
512 | "No commited data in bitmap"); | |
513 | BUFFER_TRACE2(debug_bh, bitmap_bh, "bitmap"); | |
514 | __brelse(debug_bh); | |
515 | } | |
516 | } | |
517 | jbd_lock_bh_state(bitmap_bh); | |
518 | #endif | |
519 | if (need_resched()) { | |
520 | jbd_unlock_bh_state(bitmap_bh); | |
521 | cond_resched(); | |
522 | jbd_lock_bh_state(bitmap_bh); | |
523 | } | |
524 | /* @@@ This prevents newly-allocated data from being | |
525 | * freed and then reallocated within the same | |
526 | * transaction. | |
527 | * | |
528 | * Ideally we would want to allow that to happen, but to | |
529 | * do so requires making journal_forget() capable of | |
530 | * revoking the queued write of a data block, which | |
531 | * implies blocking on the journal lock. *forget() | |
532 | * cannot block due to truncate races. | |
533 | * | |
534 | * Eventually we can fix this by making journal_forget() | |
535 | * return a status indicating whether or not it was able | |
536 | * to revoke the buffer. On successful revoke, it is | |
537 | * safe not to set the allocation bit in the committed | |
538 | * bitmap, because we know that there is no outstanding | |
539 | * activity on the buffer any more and so it is safe to | |
540 | * reallocate it. | |
541 | */ | |
542 | BUFFER_TRACE(bitmap_bh, "set in b_committed_data"); | |
543 | J_ASSERT_BH(bitmap_bh, | |
544 | bh2jh(bitmap_bh)->b_committed_data != NULL); | |
617ba13b | 545 | ext4_set_bit_atomic(sb_bgl_lock(sbi, block_group), bit + i, |
ac27a0ec DK |
546 | bh2jh(bitmap_bh)->b_committed_data); |
547 | ||
548 | /* | |
549 | * We clear the bit in the bitmap after setting the committed | |
550 | * data bit, because this is the reverse order to that which | |
551 | * the allocator uses. | |
552 | */ | |
553 | BUFFER_TRACE(bitmap_bh, "clear bit"); | |
617ba13b | 554 | if (!ext4_clear_bit_atomic(sb_bgl_lock(sbi, block_group), |
ac27a0ec DK |
555 | bit + i, bitmap_bh->b_data)) { |
556 | jbd_unlock_bh_state(bitmap_bh); | |
617ba13b | 557 | ext4_error(sb, __FUNCTION__, |
ac27a0ec DK |
558 | "bit already cleared for block "E3FSBLK, |
559 | block + i); | |
560 | jbd_lock_bh_state(bitmap_bh); | |
561 | BUFFER_TRACE(bitmap_bh, "bit already cleared"); | |
562 | } else { | |
563 | group_freed++; | |
564 | } | |
565 | } | |
566 | jbd_unlock_bh_state(bitmap_bh); | |
567 | ||
568 | spin_lock(sb_bgl_lock(sbi, block_group)); | |
569 | desc->bg_free_blocks_count = | |
570 | cpu_to_le16(le16_to_cpu(desc->bg_free_blocks_count) + | |
571 | group_freed); | |
572 | spin_unlock(sb_bgl_lock(sbi, block_group)); | |
573 | percpu_counter_mod(&sbi->s_freeblocks_counter, count); | |
574 | ||
575 | /* We dirtied the bitmap block */ | |
576 | BUFFER_TRACE(bitmap_bh, "dirtied bitmap block"); | |
617ba13b | 577 | err = ext4_journal_dirty_metadata(handle, bitmap_bh); |
ac27a0ec DK |
578 | |
579 | /* And the group descriptor block */ | |
580 | BUFFER_TRACE(gd_bh, "dirtied group descriptor block"); | |
617ba13b | 581 | ret = ext4_journal_dirty_metadata(handle, gd_bh); |
ac27a0ec DK |
582 | if (!err) err = ret; |
583 | *pdquot_freed_blocks += group_freed; | |
584 | ||
585 | if (overflow && !err) { | |
586 | block += count; | |
587 | count = overflow; | |
588 | goto do_more; | |
589 | } | |
590 | sb->s_dirt = 1; | |
591 | error_return: | |
592 | brelse(bitmap_bh); | |
617ba13b | 593 | ext4_std_error(sb, err); |
ac27a0ec DK |
594 | return; |
595 | } | |
596 | ||
597 | /** | |
617ba13b | 598 | * ext4_free_blocks() -- Free given blocks and update quota |
ac27a0ec DK |
599 | * @handle: handle for this transaction |
600 | * @inode: inode | |
601 | * @block: start physical block to free | |
602 | * @count: number of blocks to count | |
603 | */ | |
617ba13b MC |
604 | void ext4_free_blocks(handle_t *handle, struct inode *inode, |
605 | ext4_fsblk_t block, unsigned long count) | |
ac27a0ec DK |
606 | { |
607 | struct super_block * sb; | |
608 | unsigned long dquot_freed_blocks; | |
609 | ||
610 | sb = inode->i_sb; | |
611 | if (!sb) { | |
617ba13b | 612 | printk ("ext4_free_blocks: nonexistent device"); |
ac27a0ec DK |
613 | return; |
614 | } | |
617ba13b | 615 | ext4_free_blocks_sb(handle, sb, block, count, &dquot_freed_blocks); |
ac27a0ec DK |
616 | if (dquot_freed_blocks) |
617 | DQUOT_FREE_BLOCK(inode, dquot_freed_blocks); | |
618 | return; | |
619 | } | |
620 | ||
621 | /** | |
617ba13b | 622 | * ext4_test_allocatable() |
ac27a0ec DK |
623 | * @nr: given allocation block group |
624 | * @bh: bufferhead contains the bitmap of the given block group | |
625 | * | |
617ba13b | 626 | * For ext4 allocations, we must not reuse any blocks which are |
ac27a0ec DK |
627 | * allocated in the bitmap buffer's "last committed data" copy. This |
628 | * prevents deletes from freeing up the page for reuse until we have | |
629 | * committed the delete transaction. | |
630 | * | |
631 | * If we didn't do this, then deleting something and reallocating it as | |
632 | * data would allow the old block to be overwritten before the | |
633 | * transaction committed (because we force data to disk before commit). | |
634 | * This would lead to corruption if we crashed between overwriting the | |
635 | * data and committing the delete. | |
636 | * | |
637 | * @@@ We may want to make this allocation behaviour conditional on | |
638 | * data-writes at some point, and disable it for metadata allocations or | |
639 | * sync-data inodes. | |
640 | */ | |
617ba13b | 641 | static int ext4_test_allocatable(ext4_grpblk_t nr, struct buffer_head *bh) |
ac27a0ec DK |
642 | { |
643 | int ret; | |
644 | struct journal_head *jh = bh2jh(bh); | |
645 | ||
617ba13b | 646 | if (ext4_test_bit(nr, bh->b_data)) |
ac27a0ec DK |
647 | return 0; |
648 | ||
649 | jbd_lock_bh_state(bh); | |
650 | if (!jh->b_committed_data) | |
651 | ret = 1; | |
652 | else | |
617ba13b | 653 | ret = !ext4_test_bit(nr, jh->b_committed_data); |
ac27a0ec DK |
654 | jbd_unlock_bh_state(bh); |
655 | return ret; | |
656 | } | |
657 | ||
658 | /** | |
659 | * bitmap_search_next_usable_block() | |
660 | * @start: the starting block (group relative) of the search | |
661 | * @bh: bufferhead contains the block group bitmap | |
662 | * @maxblocks: the ending block (group relative) of the reservation | |
663 | * | |
664 | * The bitmap search --- search forward alternately through the actual | |
665 | * bitmap on disk and the last-committed copy in journal, until we find a | |
666 | * bit free in both bitmaps. | |
667 | */ | |
617ba13b MC |
668 | static ext4_grpblk_t |
669 | bitmap_search_next_usable_block(ext4_grpblk_t start, struct buffer_head *bh, | |
670 | ext4_grpblk_t maxblocks) | |
ac27a0ec | 671 | { |
617ba13b | 672 | ext4_grpblk_t next; |
ac27a0ec DK |
673 | struct journal_head *jh = bh2jh(bh); |
674 | ||
675 | while (start < maxblocks) { | |
617ba13b | 676 | next = ext4_find_next_zero_bit(bh->b_data, maxblocks, start); |
ac27a0ec DK |
677 | if (next >= maxblocks) |
678 | return -1; | |
617ba13b | 679 | if (ext4_test_allocatable(next, bh)) |
ac27a0ec DK |
680 | return next; |
681 | jbd_lock_bh_state(bh); | |
682 | if (jh->b_committed_data) | |
617ba13b | 683 | start = ext4_find_next_zero_bit(jh->b_committed_data, |
ac27a0ec DK |
684 | maxblocks, next); |
685 | jbd_unlock_bh_state(bh); | |
686 | } | |
687 | return -1; | |
688 | } | |
689 | ||
690 | /** | |
691 | * find_next_usable_block() | |
692 | * @start: the starting block (group relative) to find next | |
693 | * allocatable block in bitmap. | |
694 | * @bh: bufferhead contains the block group bitmap | |
695 | * @maxblocks: the ending block (group relative) for the search | |
696 | * | |
697 | * Find an allocatable block in a bitmap. We honor both the bitmap and | |
698 | * its last-committed copy (if that exists), and perform the "most | |
699 | * appropriate allocation" algorithm of looking for a free block near | |
700 | * the initial goal; then for a free byte somewhere in the bitmap; then | |
701 | * for any free bit in the bitmap. | |
702 | */ | |
617ba13b MC |
703 | static ext4_grpblk_t |
704 | find_next_usable_block(ext4_grpblk_t start, struct buffer_head *bh, | |
705 | ext4_grpblk_t maxblocks) | |
ac27a0ec | 706 | { |
617ba13b | 707 | ext4_grpblk_t here, next; |
ac27a0ec DK |
708 | char *p, *r; |
709 | ||
710 | if (start > 0) { | |
711 | /* | |
712 | * The goal was occupied; search forward for a free | |
713 | * block within the next XX blocks. | |
714 | * | |
715 | * end_goal is more or less random, but it has to be | |
617ba13b | 716 | * less than EXT4_BLOCKS_PER_GROUP. Aligning up to the |
ac27a0ec DK |
717 | * next 64-bit boundary is simple.. |
718 | */ | |
617ba13b | 719 | ext4_grpblk_t end_goal = (start + 63) & ~63; |
ac27a0ec DK |
720 | if (end_goal > maxblocks) |
721 | end_goal = maxblocks; | |
617ba13b MC |
722 | here = ext4_find_next_zero_bit(bh->b_data, end_goal, start); |
723 | if (here < end_goal && ext4_test_allocatable(here, bh)) | |
ac27a0ec | 724 | return here; |
617ba13b | 725 | ext4_debug("Bit not found near goal\n"); |
ac27a0ec DK |
726 | } |
727 | ||
728 | here = start; | |
729 | if (here < 0) | |
730 | here = 0; | |
731 | ||
732 | p = ((char *)bh->b_data) + (here >> 3); | |
733 | r = memscan(p, 0, (maxblocks - here + 7) >> 3); | |
734 | next = (r - ((char *)bh->b_data)) << 3; | |
735 | ||
617ba13b | 736 | if (next < maxblocks && next >= start && ext4_test_allocatable(next, bh)) |
ac27a0ec DK |
737 | return next; |
738 | ||
739 | /* | |
740 | * The bitmap search --- search forward alternately through the actual | |
741 | * bitmap and the last-committed copy until we find a bit free in | |
742 | * both | |
743 | */ | |
744 | here = bitmap_search_next_usable_block(here, bh, maxblocks); | |
745 | return here; | |
746 | } | |
747 | ||
748 | /** | |
749 | * claim_block() | |
750 | * @block: the free block (group relative) to allocate | |
751 | * @bh: the bufferhead containts the block group bitmap | |
752 | * | |
753 | * We think we can allocate this block in this bitmap. Try to set the bit. | |
754 | * If that succeeds then check that nobody has allocated and then freed the | |
755 | * block since we saw that is was not marked in b_committed_data. If it _was_ | |
756 | * allocated and freed then clear the bit in the bitmap again and return | |
757 | * zero (failure). | |
758 | */ | |
759 | static inline int | |
617ba13b | 760 | claim_block(spinlock_t *lock, ext4_grpblk_t block, struct buffer_head *bh) |
ac27a0ec DK |
761 | { |
762 | struct journal_head *jh = bh2jh(bh); | |
763 | int ret; | |
764 | ||
617ba13b | 765 | if (ext4_set_bit_atomic(lock, block, bh->b_data)) |
ac27a0ec DK |
766 | return 0; |
767 | jbd_lock_bh_state(bh); | |
617ba13b MC |
768 | if (jh->b_committed_data && ext4_test_bit(block,jh->b_committed_data)) { |
769 | ext4_clear_bit_atomic(lock, block, bh->b_data); | |
ac27a0ec DK |
770 | ret = 0; |
771 | } else { | |
772 | ret = 1; | |
773 | } | |
774 | jbd_unlock_bh_state(bh); | |
775 | return ret; | |
776 | } | |
777 | ||
778 | /** | |
617ba13b | 779 | * ext4_try_to_allocate() |
ac27a0ec DK |
780 | * @sb: superblock |
781 | * @handle: handle to this transaction | |
782 | * @group: given allocation block group | |
783 | * @bitmap_bh: bufferhead holds the block bitmap | |
784 | * @grp_goal: given target block within the group | |
785 | * @count: target number of blocks to allocate | |
786 | * @my_rsv: reservation window | |
787 | * | |
788 | * Attempt to allocate blocks within a give range. Set the range of allocation | |
789 | * first, then find the first free bit(s) from the bitmap (within the range), | |
790 | * and at last, allocate the blocks by claiming the found free bit as allocated. | |
791 | * | |
792 | * To set the range of this allocation: | |
793 | * if there is a reservation window, only try to allocate block(s) from the | |
794 | * file's own reservation window; | |
795 | * Otherwise, the allocation range starts from the give goal block, ends at | |
796 | * the block group's last block. | |
797 | * | |
798 | * If we failed to allocate the desired block then we may end up crossing to a | |
799 | * new bitmap. In that case we must release write access to the old one via | |
617ba13b | 800 | * ext4_journal_release_buffer(), else we'll run out of credits. |
ac27a0ec | 801 | */ |
617ba13b MC |
802 | static ext4_grpblk_t |
803 | ext4_try_to_allocate(struct super_block *sb, handle_t *handle, int group, | |
804 | struct buffer_head *bitmap_bh, ext4_grpblk_t grp_goal, | |
805 | unsigned long *count, struct ext4_reserve_window *my_rsv) | |
ac27a0ec | 806 | { |
617ba13b MC |
807 | ext4_fsblk_t group_first_block; |
808 | ext4_grpblk_t start, end; | |
ac27a0ec DK |
809 | unsigned long num = 0; |
810 | ||
811 | /* we do allocation within the reservation window if we have a window */ | |
812 | if (my_rsv) { | |
617ba13b | 813 | group_first_block = ext4_group_first_block_no(sb, group); |
ac27a0ec DK |
814 | if (my_rsv->_rsv_start >= group_first_block) |
815 | start = my_rsv->_rsv_start - group_first_block; | |
816 | else | |
817 | /* reservation window cross group boundary */ | |
818 | start = 0; | |
819 | end = my_rsv->_rsv_end - group_first_block + 1; | |
617ba13b | 820 | if (end > EXT4_BLOCKS_PER_GROUP(sb)) |
ac27a0ec | 821 | /* reservation window crosses group boundary */ |
617ba13b | 822 | end = EXT4_BLOCKS_PER_GROUP(sb); |
ac27a0ec DK |
823 | if ((start <= grp_goal) && (grp_goal < end)) |
824 | start = grp_goal; | |
825 | else | |
826 | grp_goal = -1; | |
827 | } else { | |
828 | if (grp_goal > 0) | |
829 | start = grp_goal; | |
830 | else | |
831 | start = 0; | |
617ba13b | 832 | end = EXT4_BLOCKS_PER_GROUP(sb); |
ac27a0ec DK |
833 | } |
834 | ||
617ba13b | 835 | BUG_ON(start > EXT4_BLOCKS_PER_GROUP(sb)); |
ac27a0ec DK |
836 | |
837 | repeat: | |
617ba13b | 838 | if (grp_goal < 0 || !ext4_test_allocatable(grp_goal, bitmap_bh)) { |
ac27a0ec DK |
839 | grp_goal = find_next_usable_block(start, bitmap_bh, end); |
840 | if (grp_goal < 0) | |
841 | goto fail_access; | |
842 | if (!my_rsv) { | |
843 | int i; | |
844 | ||
845 | for (i = 0; i < 7 && grp_goal > start && | |
617ba13b | 846 | ext4_test_allocatable(grp_goal - 1, |
ac27a0ec DK |
847 | bitmap_bh); |
848 | i++, grp_goal--) | |
849 | ; | |
850 | } | |
851 | } | |
852 | start = grp_goal; | |
853 | ||
617ba13b | 854 | if (!claim_block(sb_bgl_lock(EXT4_SB(sb), group), |
ac27a0ec DK |
855 | grp_goal, bitmap_bh)) { |
856 | /* | |
857 | * The block was allocated by another thread, or it was | |
858 | * allocated and then freed by another thread | |
859 | */ | |
860 | start++; | |
861 | grp_goal++; | |
862 | if (start >= end) | |
863 | goto fail_access; | |
864 | goto repeat; | |
865 | } | |
866 | num++; | |
867 | grp_goal++; | |
868 | while (num < *count && grp_goal < end | |
617ba13b MC |
869 | && ext4_test_allocatable(grp_goal, bitmap_bh) |
870 | && claim_block(sb_bgl_lock(EXT4_SB(sb), group), | |
ac27a0ec DK |
871 | grp_goal, bitmap_bh)) { |
872 | num++; | |
873 | grp_goal++; | |
874 | } | |
875 | *count = num; | |
876 | return grp_goal - num; | |
877 | fail_access: | |
878 | *count = num; | |
879 | return -1; | |
880 | } | |
881 | ||
882 | /** | |
883 | * find_next_reservable_window(): | |
884 | * find a reservable space within the given range. | |
885 | * It does not allocate the reservation window for now: | |
886 | * alloc_new_reservation() will do the work later. | |
887 | * | |
888 | * @search_head: the head of the searching list; | |
889 | * This is not necessarily the list head of the whole filesystem | |
890 | * | |
891 | * We have both head and start_block to assist the search | |
892 | * for the reservable space. The list starts from head, | |
893 | * but we will shift to the place where start_block is, | |
894 | * then start from there, when looking for a reservable space. | |
895 | * | |
896 | * @size: the target new reservation window size | |
897 | * | |
898 | * @group_first_block: the first block we consider to start | |
899 | * the real search from | |
900 | * | |
901 | * @last_block: | |
902 | * the maximum block number that our goal reservable space | |
903 | * could start from. This is normally the last block in this | |
904 | * group. The search will end when we found the start of next | |
905 | * possible reservable space is out of this boundary. | |
906 | * This could handle the cross boundary reservation window | |
907 | * request. | |
908 | * | |
909 | * basically we search from the given range, rather than the whole | |
910 | * reservation double linked list, (start_block, last_block) | |
911 | * to find a free region that is of my size and has not | |
912 | * been reserved. | |
913 | * | |
914 | */ | |
915 | static int find_next_reservable_window( | |
617ba13b MC |
916 | struct ext4_reserve_window_node *search_head, |
917 | struct ext4_reserve_window_node *my_rsv, | |
ac27a0ec | 918 | struct super_block * sb, |
617ba13b MC |
919 | ext4_fsblk_t start_block, |
920 | ext4_fsblk_t last_block) | |
ac27a0ec DK |
921 | { |
922 | struct rb_node *next; | |
617ba13b MC |
923 | struct ext4_reserve_window_node *rsv, *prev; |
924 | ext4_fsblk_t cur; | |
ac27a0ec DK |
925 | int size = my_rsv->rsv_goal_size; |
926 | ||
927 | /* TODO: make the start of the reservation window byte-aligned */ | |
928 | /* cur = *start_block & ~7;*/ | |
929 | cur = start_block; | |
930 | rsv = search_head; | |
931 | if (!rsv) | |
932 | return -1; | |
933 | ||
934 | while (1) { | |
935 | if (cur <= rsv->rsv_end) | |
936 | cur = rsv->rsv_end + 1; | |
937 | ||
938 | /* TODO? | |
939 | * in the case we could not find a reservable space | |
940 | * that is what is expected, during the re-search, we could | |
941 | * remember what's the largest reservable space we could have | |
942 | * and return that one. | |
943 | * | |
944 | * For now it will fail if we could not find the reservable | |
945 | * space with expected-size (or more)... | |
946 | */ | |
947 | if (cur > last_block) | |
948 | return -1; /* fail */ | |
949 | ||
950 | prev = rsv; | |
951 | next = rb_next(&rsv->rsv_node); | |
617ba13b | 952 | rsv = list_entry(next,struct ext4_reserve_window_node,rsv_node); |
ac27a0ec DK |
953 | |
954 | /* | |
955 | * Reached the last reservation, we can just append to the | |
956 | * previous one. | |
957 | */ | |
958 | if (!next) | |
959 | break; | |
960 | ||
961 | if (cur + size <= rsv->rsv_start) { | |
962 | /* | |
963 | * Found a reserveable space big enough. We could | |
964 | * have a reservation across the group boundary here | |
965 | */ | |
966 | break; | |
967 | } | |
968 | } | |
969 | /* | |
970 | * we come here either : | |
971 | * when we reach the end of the whole list, | |
972 | * and there is empty reservable space after last entry in the list. | |
973 | * append it to the end of the list. | |
974 | * | |
975 | * or we found one reservable space in the middle of the list, | |
976 | * return the reservation window that we could append to. | |
977 | * succeed. | |
978 | */ | |
979 | ||
980 | if ((prev != my_rsv) && (!rsv_is_empty(&my_rsv->rsv_window))) | |
981 | rsv_window_remove(sb, my_rsv); | |
982 | ||
983 | /* | |
984 | * Let's book the whole avaliable window for now. We will check the | |
985 | * disk bitmap later and then, if there are free blocks then we adjust | |
986 | * the window size if it's larger than requested. | |
987 | * Otherwise, we will remove this node from the tree next time | |
988 | * call find_next_reservable_window. | |
989 | */ | |
990 | my_rsv->rsv_start = cur; | |
991 | my_rsv->rsv_end = cur + size - 1; | |
992 | my_rsv->rsv_alloc_hit = 0; | |
993 | ||
994 | if (prev != my_rsv) | |
617ba13b | 995 | ext4_rsv_window_add(sb, my_rsv); |
ac27a0ec DK |
996 | |
997 | return 0; | |
998 | } | |
999 | ||
1000 | /** | |
1001 | * alloc_new_reservation()--allocate a new reservation window | |
1002 | * | |
1003 | * To make a new reservation, we search part of the filesystem | |
1004 | * reservation list (the list that inside the group). We try to | |
1005 | * allocate a new reservation window near the allocation goal, | |
1006 | * or the beginning of the group, if there is no goal. | |
1007 | * | |
1008 | * We first find a reservable space after the goal, then from | |
1009 | * there, we check the bitmap for the first free block after | |
1010 | * it. If there is no free block until the end of group, then the | |
1011 | * whole group is full, we failed. Otherwise, check if the free | |
1012 | * block is inside the expected reservable space, if so, we | |
1013 | * succeed. | |
1014 | * If the first free block is outside the reservable space, then | |
1015 | * start from the first free block, we search for next available | |
1016 | * space, and go on. | |
1017 | * | |
1018 | * on succeed, a new reservation will be found and inserted into the list | |
1019 | * It contains at least one free block, and it does not overlap with other | |
1020 | * reservation windows. | |
1021 | * | |
1022 | * failed: we failed to find a reservation window in this group | |
1023 | * | |
1024 | * @rsv: the reservation | |
1025 | * | |
1026 | * @grp_goal: The goal (group-relative). It is where the search for a | |
1027 | * free reservable space should start from. | |
1028 | * if we have a grp_goal(grp_goal >0 ), then start from there, | |
1029 | * no grp_goal(grp_goal = -1), we start from the first block | |
1030 | * of the group. | |
1031 | * | |
1032 | * @sb: the super block | |
1033 | * @group: the group we are trying to allocate in | |
1034 | * @bitmap_bh: the block group block bitmap | |
1035 | * | |
1036 | */ | |
617ba13b MC |
1037 | static int alloc_new_reservation(struct ext4_reserve_window_node *my_rsv, |
1038 | ext4_grpblk_t grp_goal, struct super_block *sb, | |
ac27a0ec DK |
1039 | unsigned int group, struct buffer_head *bitmap_bh) |
1040 | { | |
617ba13b MC |
1041 | struct ext4_reserve_window_node *search_head; |
1042 | ext4_fsblk_t group_first_block, group_end_block, start_block; | |
1043 | ext4_grpblk_t first_free_block; | |
1044 | struct rb_root *fs_rsv_root = &EXT4_SB(sb)->s_rsv_window_root; | |
ac27a0ec DK |
1045 | unsigned long size; |
1046 | int ret; | |
617ba13b | 1047 | spinlock_t *rsv_lock = &EXT4_SB(sb)->s_rsv_window_lock; |
ac27a0ec | 1048 | |
617ba13b MC |
1049 | group_first_block = ext4_group_first_block_no(sb, group); |
1050 | group_end_block = group_first_block + (EXT4_BLOCKS_PER_GROUP(sb) - 1); | |
ac27a0ec DK |
1051 | |
1052 | if (grp_goal < 0) | |
1053 | start_block = group_first_block; | |
1054 | else | |
1055 | start_block = grp_goal + group_first_block; | |
1056 | ||
1057 | size = my_rsv->rsv_goal_size; | |
1058 | ||
1059 | if (!rsv_is_empty(&my_rsv->rsv_window)) { | |
1060 | /* | |
1061 | * if the old reservation is cross group boundary | |
1062 | * and if the goal is inside the old reservation window, | |
1063 | * we will come here when we just failed to allocate from | |
1064 | * the first part of the window. We still have another part | |
1065 | * that belongs to the next group. In this case, there is no | |
1066 | * point to discard our window and try to allocate a new one | |
1067 | * in this group(which will fail). we should | |
1068 | * keep the reservation window, just simply move on. | |
1069 | * | |
1070 | * Maybe we could shift the start block of the reservation | |
1071 | * window to the first block of next group. | |
1072 | */ | |
1073 | ||
1074 | if ((my_rsv->rsv_start <= group_end_block) && | |
1075 | (my_rsv->rsv_end > group_end_block) && | |
1076 | (start_block >= my_rsv->rsv_start)) | |
1077 | return -1; | |
1078 | ||
1079 | if ((my_rsv->rsv_alloc_hit > | |
1080 | (my_rsv->rsv_end - my_rsv->rsv_start + 1) / 2)) { | |
1081 | /* | |
1082 | * if the previously allocation hit ratio is | |
1083 | * greater than 1/2, then we double the size of | |
1084 | * the reservation window the next time, | |
1085 | * otherwise we keep the same size window | |
1086 | */ | |
1087 | size = size * 2; | |
617ba13b MC |
1088 | if (size > EXT4_MAX_RESERVE_BLOCKS) |
1089 | size = EXT4_MAX_RESERVE_BLOCKS; | |
ac27a0ec DK |
1090 | my_rsv->rsv_goal_size= size; |
1091 | } | |
1092 | } | |
1093 | ||
1094 | spin_lock(rsv_lock); | |
1095 | /* | |
1096 | * shift the search start to the window near the goal block | |
1097 | */ | |
1098 | search_head = search_reserve_window(fs_rsv_root, start_block); | |
1099 | ||
1100 | /* | |
1101 | * find_next_reservable_window() simply finds a reservable window | |
1102 | * inside the given range(start_block, group_end_block). | |
1103 | * | |
1104 | * To make sure the reservation window has a free bit inside it, we | |
1105 | * need to check the bitmap after we found a reservable window. | |
1106 | */ | |
1107 | retry: | |
1108 | ret = find_next_reservable_window(search_head, my_rsv, sb, | |
1109 | start_block, group_end_block); | |
1110 | ||
1111 | if (ret == -1) { | |
1112 | if (!rsv_is_empty(&my_rsv->rsv_window)) | |
1113 | rsv_window_remove(sb, my_rsv); | |
1114 | spin_unlock(rsv_lock); | |
1115 | return -1; | |
1116 | } | |
1117 | ||
1118 | /* | |
1119 | * On success, find_next_reservable_window() returns the | |
1120 | * reservation window where there is a reservable space after it. | |
1121 | * Before we reserve this reservable space, we need | |
1122 | * to make sure there is at least a free block inside this region. | |
1123 | * | |
1124 | * searching the first free bit on the block bitmap and copy of | |
1125 | * last committed bitmap alternatively, until we found a allocatable | |
1126 | * block. Search start from the start block of the reservable space | |
1127 | * we just found. | |
1128 | */ | |
1129 | spin_unlock(rsv_lock); | |
1130 | first_free_block = bitmap_search_next_usable_block( | |
1131 | my_rsv->rsv_start - group_first_block, | |
1132 | bitmap_bh, group_end_block - group_first_block + 1); | |
1133 | ||
1134 | if (first_free_block < 0) { | |
1135 | /* | |
1136 | * no free block left on the bitmap, no point | |
1137 | * to reserve the space. return failed. | |
1138 | */ | |
1139 | spin_lock(rsv_lock); | |
1140 | if (!rsv_is_empty(&my_rsv->rsv_window)) | |
1141 | rsv_window_remove(sb, my_rsv); | |
1142 | spin_unlock(rsv_lock); | |
1143 | return -1; /* failed */ | |
1144 | } | |
1145 | ||
1146 | start_block = first_free_block + group_first_block; | |
1147 | /* | |
1148 | * check if the first free block is within the | |
1149 | * free space we just reserved | |
1150 | */ | |
1151 | if (start_block >= my_rsv->rsv_start && start_block < my_rsv->rsv_end) | |
1152 | return 0; /* success */ | |
1153 | /* | |
1154 | * if the first free bit we found is out of the reservable space | |
1155 | * continue search for next reservable space, | |
1156 | * start from where the free block is, | |
1157 | * we also shift the list head to where we stopped last time | |
1158 | */ | |
1159 | search_head = my_rsv; | |
1160 | spin_lock(rsv_lock); | |
1161 | goto retry; | |
1162 | } | |
1163 | ||
1164 | /** | |
1165 | * try_to_extend_reservation() | |
1166 | * @my_rsv: given reservation window | |
1167 | * @sb: super block | |
1168 | * @size: the delta to extend | |
1169 | * | |
1170 | * Attempt to expand the reservation window large enough to have | |
1171 | * required number of free blocks | |
1172 | * | |
617ba13b | 1173 | * Since ext4_try_to_allocate() will always allocate blocks within |
ac27a0ec DK |
1174 | * the reservation window range, if the window size is too small, |
1175 | * multiple blocks allocation has to stop at the end of the reservation | |
1176 | * window. To make this more efficient, given the total number of | |
1177 | * blocks needed and the current size of the window, we try to | |
1178 | * expand the reservation window size if necessary on a best-effort | |
617ba13b | 1179 | * basis before ext4_new_blocks() tries to allocate blocks, |
ac27a0ec | 1180 | */ |
617ba13b | 1181 | static void try_to_extend_reservation(struct ext4_reserve_window_node *my_rsv, |
ac27a0ec DK |
1182 | struct super_block *sb, int size) |
1183 | { | |
617ba13b | 1184 | struct ext4_reserve_window_node *next_rsv; |
ac27a0ec | 1185 | struct rb_node *next; |
617ba13b | 1186 | spinlock_t *rsv_lock = &EXT4_SB(sb)->s_rsv_window_lock; |
ac27a0ec DK |
1187 | |
1188 | if (!spin_trylock(rsv_lock)) | |
1189 | return; | |
1190 | ||
1191 | next = rb_next(&my_rsv->rsv_node); | |
1192 | ||
1193 | if (!next) | |
1194 | my_rsv->rsv_end += size; | |
1195 | else { | |
617ba13b | 1196 | next_rsv = list_entry(next, struct ext4_reserve_window_node, rsv_node); |
ac27a0ec DK |
1197 | |
1198 | if ((next_rsv->rsv_start - my_rsv->rsv_end - 1) >= size) | |
1199 | my_rsv->rsv_end += size; | |
1200 | else | |
1201 | my_rsv->rsv_end = next_rsv->rsv_start - 1; | |
1202 | } | |
1203 | spin_unlock(rsv_lock); | |
1204 | } | |
1205 | ||
1206 | /** | |
617ba13b | 1207 | * ext4_try_to_allocate_with_rsv() |
ac27a0ec DK |
1208 | * @sb: superblock |
1209 | * @handle: handle to this transaction | |
1210 | * @group: given allocation block group | |
1211 | * @bitmap_bh: bufferhead holds the block bitmap | |
1212 | * @grp_goal: given target block within the group | |
1213 | * @count: target number of blocks to allocate | |
1214 | * @my_rsv: reservation window | |
1215 | * @errp: pointer to store the error code | |
1216 | * | |
1217 | * This is the main function used to allocate a new block and its reservation | |
1218 | * window. | |
1219 | * | |
1220 | * Each time when a new block allocation is need, first try to allocate from | |
1221 | * its own reservation. If it does not have a reservation window, instead of | |
1222 | * looking for a free bit on bitmap first, then look up the reservation list to | |
1223 | * see if it is inside somebody else's reservation window, we try to allocate a | |
1224 | * reservation window for it starting from the goal first. Then do the block | |
1225 | * allocation within the reservation window. | |
1226 | * | |
1227 | * This will avoid keeping on searching the reservation list again and | |
1228 | * again when somebody is looking for a free block (without | |
1229 | * reservation), and there are lots of free blocks, but they are all | |
1230 | * being reserved. | |
1231 | * | |
1232 | * We use a red-black tree for the per-filesystem reservation list. | |
1233 | * | |
1234 | */ | |
617ba13b MC |
1235 | static ext4_grpblk_t |
1236 | ext4_try_to_allocate_with_rsv(struct super_block *sb, handle_t *handle, | |
ac27a0ec | 1237 | unsigned int group, struct buffer_head *bitmap_bh, |
617ba13b MC |
1238 | ext4_grpblk_t grp_goal, |
1239 | struct ext4_reserve_window_node * my_rsv, | |
ac27a0ec DK |
1240 | unsigned long *count, int *errp) |
1241 | { | |
617ba13b MC |
1242 | ext4_fsblk_t group_first_block, group_last_block; |
1243 | ext4_grpblk_t ret = 0; | |
ac27a0ec DK |
1244 | int fatal; |
1245 | unsigned long num = *count; | |
1246 | ||
1247 | *errp = 0; | |
1248 | ||
1249 | /* | |
1250 | * Make sure we use undo access for the bitmap, because it is critical | |
1251 | * that we do the frozen_data COW on bitmap buffers in all cases even | |
1252 | * if the buffer is in BJ_Forget state in the committing transaction. | |
1253 | */ | |
1254 | BUFFER_TRACE(bitmap_bh, "get undo access for new block"); | |
617ba13b | 1255 | fatal = ext4_journal_get_undo_access(handle, bitmap_bh); |
ac27a0ec DK |
1256 | if (fatal) { |
1257 | *errp = fatal; | |
1258 | return -1; | |
1259 | } | |
1260 | ||
1261 | /* | |
1262 | * we don't deal with reservation when | |
1263 | * filesystem is mounted without reservation | |
1264 | * or the file is not a regular file | |
1265 | * or last attempt to allocate a block with reservation turned on failed | |
1266 | */ | |
1267 | if (my_rsv == NULL ) { | |
617ba13b | 1268 | ret = ext4_try_to_allocate(sb, handle, group, bitmap_bh, |
ac27a0ec DK |
1269 | grp_goal, count, NULL); |
1270 | goto out; | |
1271 | } | |
1272 | /* | |
1273 | * grp_goal is a group relative block number (if there is a goal) | |
617ba13b | 1274 | * 0 < grp_goal < EXT4_BLOCKS_PER_GROUP(sb) |
ac27a0ec DK |
1275 | * first block is a filesystem wide block number |
1276 | * first block is the block number of the first block in this group | |
1277 | */ | |
617ba13b MC |
1278 | group_first_block = ext4_group_first_block_no(sb, group); |
1279 | group_last_block = group_first_block + (EXT4_BLOCKS_PER_GROUP(sb) - 1); | |
ac27a0ec DK |
1280 | |
1281 | /* | |
1282 | * Basically we will allocate a new block from inode's reservation | |
1283 | * window. | |
1284 | * | |
1285 | * We need to allocate a new reservation window, if: | |
1286 | * a) inode does not have a reservation window; or | |
1287 | * b) last attempt to allocate a block from existing reservation | |
1288 | * failed; or | |
1289 | * c) we come here with a goal and with a reservation window | |
1290 | * | |
1291 | * We do not need to allocate a new reservation window if we come here | |
1292 | * at the beginning with a goal and the goal is inside the window, or | |
1293 | * we don't have a goal but already have a reservation window. | |
1294 | * then we could go to allocate from the reservation window directly. | |
1295 | */ | |
1296 | while (1) { | |
1297 | if (rsv_is_empty(&my_rsv->rsv_window) || (ret < 0) || | |
1298 | !goal_in_my_reservation(&my_rsv->rsv_window, | |
1299 | grp_goal, group, sb)) { | |
1300 | if (my_rsv->rsv_goal_size < *count) | |
1301 | my_rsv->rsv_goal_size = *count; | |
1302 | ret = alloc_new_reservation(my_rsv, grp_goal, sb, | |
1303 | group, bitmap_bh); | |
1304 | if (ret < 0) | |
1305 | break; /* failed */ | |
1306 | ||
1307 | if (!goal_in_my_reservation(&my_rsv->rsv_window, | |
1308 | grp_goal, group, sb)) | |
1309 | grp_goal = -1; | |
1310 | } else if (grp_goal > 0 && | |
1311 | (my_rsv->rsv_end-grp_goal+1) < *count) | |
1312 | try_to_extend_reservation(my_rsv, sb, | |
1313 | *count-my_rsv->rsv_end + grp_goal - 1); | |
1314 | ||
1315 | if ((my_rsv->rsv_start > group_last_block) || | |
1316 | (my_rsv->rsv_end < group_first_block)) { | |
617ba13b | 1317 | rsv_window_dump(&EXT4_SB(sb)->s_rsv_window_root, 1); |
ac27a0ec DK |
1318 | BUG(); |
1319 | } | |
617ba13b | 1320 | ret = ext4_try_to_allocate(sb, handle, group, bitmap_bh, |
ac27a0ec DK |
1321 | grp_goal, &num, &my_rsv->rsv_window); |
1322 | if (ret >= 0) { | |
1323 | my_rsv->rsv_alloc_hit += num; | |
1324 | *count = num; | |
1325 | break; /* succeed */ | |
1326 | } | |
1327 | num = *count; | |
1328 | } | |
1329 | out: | |
1330 | if (ret >= 0) { | |
1331 | BUFFER_TRACE(bitmap_bh, "journal_dirty_metadata for " | |
1332 | "bitmap block"); | |
617ba13b | 1333 | fatal = ext4_journal_dirty_metadata(handle, bitmap_bh); |
ac27a0ec DK |
1334 | if (fatal) { |
1335 | *errp = fatal; | |
1336 | return -1; | |
1337 | } | |
1338 | return ret; | |
1339 | } | |
1340 | ||
1341 | BUFFER_TRACE(bitmap_bh, "journal_release_buffer"); | |
617ba13b | 1342 | ext4_journal_release_buffer(handle, bitmap_bh); |
ac27a0ec DK |
1343 | return ret; |
1344 | } | |
1345 | ||
1346 | /** | |
617ba13b | 1347 | * ext4_has_free_blocks() |
ac27a0ec DK |
1348 | * @sbi: in-core super block structure. |
1349 | * | |
1350 | * Check if filesystem has at least 1 free block available for allocation. | |
1351 | */ | |
617ba13b | 1352 | static int ext4_has_free_blocks(struct ext4_sb_info *sbi) |
ac27a0ec | 1353 | { |
617ba13b | 1354 | ext4_fsblk_t free_blocks, root_blocks; |
ac27a0ec DK |
1355 | |
1356 | free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter); | |
1357 | root_blocks = le32_to_cpu(sbi->s_es->s_r_blocks_count); | |
1358 | if (free_blocks < root_blocks + 1 && !capable(CAP_SYS_RESOURCE) && | |
1359 | sbi->s_resuid != current->fsuid && | |
1360 | (sbi->s_resgid == 0 || !in_group_p (sbi->s_resgid))) { | |
1361 | return 0; | |
1362 | } | |
1363 | return 1; | |
1364 | } | |
1365 | ||
1366 | /** | |
617ba13b | 1367 | * ext4_should_retry_alloc() |
ac27a0ec DK |
1368 | * @sb: super block |
1369 | * @retries number of attemps has been made | |
1370 | * | |
617ba13b | 1371 | * ext4_should_retry_alloc() is called when ENOSPC is returned, and if |
ac27a0ec DK |
1372 | * it is profitable to retry the operation, this function will wait |
1373 | * for the current or commiting transaction to complete, and then | |
1374 | * return TRUE. | |
1375 | * | |
1376 | * if the total number of retries exceed three times, return FALSE. | |
1377 | */ | |
617ba13b | 1378 | int ext4_should_retry_alloc(struct super_block *sb, int *retries) |
ac27a0ec | 1379 | { |
617ba13b | 1380 | if (!ext4_has_free_blocks(EXT4_SB(sb)) || (*retries)++ > 3) |
ac27a0ec DK |
1381 | return 0; |
1382 | ||
1383 | jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id); | |
1384 | ||
617ba13b | 1385 | return journal_force_commit_nested(EXT4_SB(sb)->s_journal); |
ac27a0ec DK |
1386 | } |
1387 | ||
1388 | /** | |
617ba13b | 1389 | * ext4_new_blocks() -- core block(s) allocation function |
ac27a0ec DK |
1390 | * @handle: handle to this transaction |
1391 | * @inode: file inode | |
1392 | * @goal: given target block(filesystem wide) | |
1393 | * @count: target number of blocks to allocate | |
1394 | * @errp: error code | |
1395 | * | |
617ba13b | 1396 | * ext4_new_blocks uses a goal block to assist allocation. It tries to |
ac27a0ec DK |
1397 | * allocate block(s) from the block group contains the goal block first. If that |
1398 | * fails, it will try to allocate block(s) from other block groups without | |
1399 | * any specific goal block. | |
1400 | * | |
1401 | */ | |
617ba13b MC |
1402 | ext4_fsblk_t ext4_new_blocks(handle_t *handle, struct inode *inode, |
1403 | ext4_fsblk_t goal, unsigned long *count, int *errp) | |
ac27a0ec DK |
1404 | { |
1405 | struct buffer_head *bitmap_bh = NULL; | |
1406 | struct buffer_head *gdp_bh; | |
1407 | int group_no; | |
1408 | int goal_group; | |
617ba13b MC |
1409 | ext4_grpblk_t grp_target_blk; /* blockgroup relative goal block */ |
1410 | ext4_grpblk_t grp_alloc_blk; /* blockgroup-relative allocated block*/ | |
1411 | ext4_fsblk_t ret_block; /* filesyetem-wide allocated block */ | |
ac27a0ec DK |
1412 | int bgi; /* blockgroup iteration index */ |
1413 | int fatal = 0, err; | |
1414 | int performed_allocation = 0; | |
617ba13b | 1415 | ext4_grpblk_t free_blocks; /* number of free blocks in a group */ |
ac27a0ec | 1416 | struct super_block *sb; |
617ba13b MC |
1417 | struct ext4_group_desc *gdp; |
1418 | struct ext4_super_block *es; | |
1419 | struct ext4_sb_info *sbi; | |
1420 | struct ext4_reserve_window_node *my_rsv = NULL; | |
1421 | struct ext4_block_alloc_info *block_i; | |
ac27a0ec | 1422 | unsigned short windowsz = 0; |
617ba13b | 1423 | #ifdef EXT4FS_DEBUG |
ac27a0ec DK |
1424 | static int goal_hits, goal_attempts; |
1425 | #endif | |
1426 | unsigned long ngroups; | |
1427 | unsigned long num = *count; | |
1428 | ||
1429 | *errp = -ENOSPC; | |
1430 | sb = inode->i_sb; | |
1431 | if (!sb) { | |
617ba13b | 1432 | printk("ext4_new_block: nonexistent device"); |
ac27a0ec DK |
1433 | return 0; |
1434 | } | |
1435 | ||
1436 | /* | |
1437 | * Check quota for allocation of this block. | |
1438 | */ | |
1439 | if (DQUOT_ALLOC_BLOCK(inode, num)) { | |
1440 | *errp = -EDQUOT; | |
1441 | return 0; | |
1442 | } | |
1443 | ||
617ba13b MC |
1444 | sbi = EXT4_SB(sb); |
1445 | es = EXT4_SB(sb)->s_es; | |
1446 | ext4_debug("goal=%lu.\n", goal); | |
ac27a0ec DK |
1447 | /* |
1448 | * Allocate a block from reservation only when | |
1449 | * filesystem is mounted with reservation(default,-o reservation), and | |
1450 | * it's a regular file, and | |
1451 | * the desired window size is greater than 0 (One could use ioctl | |
617ba13b | 1452 | * command EXT4_IOC_SETRSVSZ to set the window size to 0 to turn off |
ac27a0ec DK |
1453 | * reservation on that particular file) |
1454 | */ | |
617ba13b | 1455 | block_i = EXT4_I(inode)->i_block_alloc_info; |
ac27a0ec DK |
1456 | if (block_i && ((windowsz = block_i->rsv_window_node.rsv_goal_size) > 0)) |
1457 | my_rsv = &block_i->rsv_window_node; | |
1458 | ||
617ba13b | 1459 | if (!ext4_has_free_blocks(sbi)) { |
ac27a0ec DK |
1460 | *errp = -ENOSPC; |
1461 | goto out; | |
1462 | } | |
1463 | ||
1464 | /* | |
1465 | * First, test whether the goal block is free. | |
1466 | */ | |
1467 | if (goal < le32_to_cpu(es->s_first_data_block) || | |
1468 | goal >= le32_to_cpu(es->s_blocks_count)) | |
1469 | goal = le32_to_cpu(es->s_first_data_block); | |
1470 | group_no = (goal - le32_to_cpu(es->s_first_data_block)) / | |
617ba13b | 1471 | EXT4_BLOCKS_PER_GROUP(sb); |
ac27a0ec DK |
1472 | goal_group = group_no; |
1473 | retry_alloc: | |
617ba13b | 1474 | gdp = ext4_get_group_desc(sb, group_no, &gdp_bh); |
ac27a0ec DK |
1475 | if (!gdp) |
1476 | goto io_error; | |
1477 | ||
1478 | free_blocks = le16_to_cpu(gdp->bg_free_blocks_count); | |
1479 | /* | |
1480 | * if there is not enough free blocks to make a new resevation | |
1481 | * turn off reservation for this allocation | |
1482 | */ | |
1483 | if (my_rsv && (free_blocks < windowsz) | |
1484 | && (rsv_is_empty(&my_rsv->rsv_window))) | |
1485 | my_rsv = NULL; | |
1486 | ||
1487 | if (free_blocks > 0) { | |
1488 | grp_target_blk = ((goal - le32_to_cpu(es->s_first_data_block)) % | |
617ba13b | 1489 | EXT4_BLOCKS_PER_GROUP(sb)); |
ac27a0ec DK |
1490 | bitmap_bh = read_block_bitmap(sb, group_no); |
1491 | if (!bitmap_bh) | |
1492 | goto io_error; | |
617ba13b | 1493 | grp_alloc_blk = ext4_try_to_allocate_with_rsv(sb, handle, |
ac27a0ec DK |
1494 | group_no, bitmap_bh, grp_target_blk, |
1495 | my_rsv, &num, &fatal); | |
1496 | if (fatal) | |
1497 | goto out; | |
1498 | if (grp_alloc_blk >= 0) | |
1499 | goto allocated; | |
1500 | } | |
1501 | ||
617ba13b | 1502 | ngroups = EXT4_SB(sb)->s_groups_count; |
ac27a0ec DK |
1503 | smp_rmb(); |
1504 | ||
1505 | /* | |
1506 | * Now search the rest of the groups. We assume that | |
1507 | * i and gdp correctly point to the last group visited. | |
1508 | */ | |
1509 | for (bgi = 0; bgi < ngroups; bgi++) { | |
1510 | group_no++; | |
1511 | if (group_no >= ngroups) | |
1512 | group_no = 0; | |
617ba13b | 1513 | gdp = ext4_get_group_desc(sb, group_no, &gdp_bh); |
ac27a0ec DK |
1514 | if (!gdp) { |
1515 | *errp = -EIO; | |
1516 | goto out; | |
1517 | } | |
1518 | free_blocks = le16_to_cpu(gdp->bg_free_blocks_count); | |
1519 | /* | |
1520 | * skip this group if the number of | |
1521 | * free blocks is less than half of the reservation | |
1522 | * window size. | |
1523 | */ | |
1524 | if (free_blocks <= (windowsz/2)) | |
1525 | continue; | |
1526 | ||
1527 | brelse(bitmap_bh); | |
1528 | bitmap_bh = read_block_bitmap(sb, group_no); | |
1529 | if (!bitmap_bh) | |
1530 | goto io_error; | |
1531 | /* | |
1532 | * try to allocate block(s) from this group, without a goal(-1). | |
1533 | */ | |
617ba13b | 1534 | grp_alloc_blk = ext4_try_to_allocate_with_rsv(sb, handle, |
ac27a0ec DK |
1535 | group_no, bitmap_bh, -1, my_rsv, |
1536 | &num, &fatal); | |
1537 | if (fatal) | |
1538 | goto out; | |
1539 | if (grp_alloc_blk >= 0) | |
1540 | goto allocated; | |
1541 | } | |
1542 | /* | |
1543 | * We may end up a bogus ealier ENOSPC error due to | |
1544 | * filesystem is "full" of reservations, but | |
1545 | * there maybe indeed free blocks avaliable on disk | |
1546 | * In this case, we just forget about the reservations | |
1547 | * just do block allocation as without reservations. | |
1548 | */ | |
1549 | if (my_rsv) { | |
1550 | my_rsv = NULL; | |
1551 | group_no = goal_group; | |
1552 | goto retry_alloc; | |
1553 | } | |
1554 | /* No space left on the device */ | |
1555 | *errp = -ENOSPC; | |
1556 | goto out; | |
1557 | ||
1558 | allocated: | |
1559 | ||
617ba13b | 1560 | ext4_debug("using block group %d(%d)\n", |
ac27a0ec DK |
1561 | group_no, gdp->bg_free_blocks_count); |
1562 | ||
1563 | BUFFER_TRACE(gdp_bh, "get_write_access"); | |
617ba13b | 1564 | fatal = ext4_journal_get_write_access(handle, gdp_bh); |
ac27a0ec DK |
1565 | if (fatal) |
1566 | goto out; | |
1567 | ||
617ba13b | 1568 | ret_block = grp_alloc_blk + ext4_group_first_block_no(sb, group_no); |
ac27a0ec DK |
1569 | |
1570 | if (in_range(le32_to_cpu(gdp->bg_block_bitmap), ret_block, num) || | |
1571 | in_range(le32_to_cpu(gdp->bg_inode_bitmap), ret_block, num) || | |
1572 | in_range(ret_block, le32_to_cpu(gdp->bg_inode_table), | |
617ba13b | 1573 | EXT4_SB(sb)->s_itb_per_group) || |
ac27a0ec | 1574 | in_range(ret_block + num - 1, le32_to_cpu(gdp->bg_inode_table), |
617ba13b MC |
1575 | EXT4_SB(sb)->s_itb_per_group)) |
1576 | ext4_error(sb, "ext4_new_block", | |
ac27a0ec DK |
1577 | "Allocating block in system zone - " |
1578 | "blocks from "E3FSBLK", length %lu", | |
1579 | ret_block, num); | |
1580 | ||
1581 | performed_allocation = 1; | |
1582 | ||
1583 | #ifdef CONFIG_JBD_DEBUG | |
1584 | { | |
1585 | struct buffer_head *debug_bh; | |
1586 | ||
1587 | /* Record bitmap buffer state in the newly allocated block */ | |
1588 | debug_bh = sb_find_get_block(sb, ret_block); | |
1589 | if (debug_bh) { | |
1590 | BUFFER_TRACE(debug_bh, "state when allocated"); | |
1591 | BUFFER_TRACE2(debug_bh, bitmap_bh, "bitmap state"); | |
1592 | brelse(debug_bh); | |
1593 | } | |
1594 | } | |
1595 | jbd_lock_bh_state(bitmap_bh); | |
1596 | spin_lock(sb_bgl_lock(sbi, group_no)); | |
1597 | if (buffer_jbd(bitmap_bh) && bh2jh(bitmap_bh)->b_committed_data) { | |
1598 | int i; | |
1599 | ||
1600 | for (i = 0; i < num; i++) { | |
617ba13b | 1601 | if (ext4_test_bit(grp_alloc_blk+i, |
ac27a0ec DK |
1602 | bh2jh(bitmap_bh)->b_committed_data)) { |
1603 | printk("%s: block was unexpectedly set in " | |
1604 | "b_committed_data\n", __FUNCTION__); | |
1605 | } | |
1606 | } | |
1607 | } | |
617ba13b | 1608 | ext4_debug("found bit %d\n", grp_alloc_blk); |
ac27a0ec DK |
1609 | spin_unlock(sb_bgl_lock(sbi, group_no)); |
1610 | jbd_unlock_bh_state(bitmap_bh); | |
1611 | #endif | |
1612 | ||
1613 | if (ret_block + num - 1 >= le32_to_cpu(es->s_blocks_count)) { | |
617ba13b | 1614 | ext4_error(sb, "ext4_new_block", |
ac27a0ec DK |
1615 | "block("E3FSBLK") >= blocks count(%d) - " |
1616 | "block_group = %d, es == %p ", ret_block, | |
1617 | le32_to_cpu(es->s_blocks_count), group_no, es); | |
1618 | goto out; | |
1619 | } | |
1620 | ||
1621 | /* | |
1622 | * It is up to the caller to add the new buffer to a journal | |
1623 | * list of some description. We don't know in advance whether | |
1624 | * the caller wants to use it as metadata or data. | |
1625 | */ | |
617ba13b | 1626 | ext4_debug("allocating block %lu. Goal hits %d of %d.\n", |
ac27a0ec DK |
1627 | ret_block, goal_hits, goal_attempts); |
1628 | ||
1629 | spin_lock(sb_bgl_lock(sbi, group_no)); | |
1630 | gdp->bg_free_blocks_count = | |
1631 | cpu_to_le16(le16_to_cpu(gdp->bg_free_blocks_count)-num); | |
1632 | spin_unlock(sb_bgl_lock(sbi, group_no)); | |
1633 | percpu_counter_mod(&sbi->s_freeblocks_counter, -num); | |
1634 | ||
1635 | BUFFER_TRACE(gdp_bh, "journal_dirty_metadata for group descriptor"); | |
617ba13b | 1636 | err = ext4_journal_dirty_metadata(handle, gdp_bh); |
ac27a0ec DK |
1637 | if (!fatal) |
1638 | fatal = err; | |
1639 | ||
1640 | sb->s_dirt = 1; | |
1641 | if (fatal) | |
1642 | goto out; | |
1643 | ||
1644 | *errp = 0; | |
1645 | brelse(bitmap_bh); | |
1646 | DQUOT_FREE_BLOCK(inode, *count-num); | |
1647 | *count = num; | |
1648 | return ret_block; | |
1649 | ||
1650 | io_error: | |
1651 | *errp = -EIO; | |
1652 | out: | |
1653 | if (fatal) { | |
1654 | *errp = fatal; | |
617ba13b | 1655 | ext4_std_error(sb, fatal); |
ac27a0ec DK |
1656 | } |
1657 | /* | |
1658 | * Undo the block allocation | |
1659 | */ | |
1660 | if (!performed_allocation) | |
1661 | DQUOT_FREE_BLOCK(inode, *count); | |
1662 | brelse(bitmap_bh); | |
1663 | return 0; | |
1664 | } | |
1665 | ||
617ba13b MC |
1666 | ext4_fsblk_t ext4_new_block(handle_t *handle, struct inode *inode, |
1667 | ext4_fsblk_t goal, int *errp) | |
ac27a0ec DK |
1668 | { |
1669 | unsigned long count = 1; | |
1670 | ||
617ba13b | 1671 | return ext4_new_blocks(handle, inode, goal, &count, errp); |
ac27a0ec DK |
1672 | } |
1673 | ||
1674 | /** | |
617ba13b | 1675 | * ext4_count_free_blocks() -- count filesystem free blocks |
ac27a0ec DK |
1676 | * @sb: superblock |
1677 | * | |
1678 | * Adds up the number of free blocks from each block group. | |
1679 | */ | |
617ba13b | 1680 | ext4_fsblk_t ext4_count_free_blocks(struct super_block *sb) |
ac27a0ec | 1681 | { |
617ba13b MC |
1682 | ext4_fsblk_t desc_count; |
1683 | struct ext4_group_desc *gdp; | |
ac27a0ec | 1684 | int i; |
617ba13b MC |
1685 | unsigned long ngroups = EXT4_SB(sb)->s_groups_count; |
1686 | #ifdef EXT4FS_DEBUG | |
1687 | struct ext4_super_block *es; | |
1688 | ext4_fsblk_t bitmap_count; | |
ac27a0ec DK |
1689 | unsigned long x; |
1690 | struct buffer_head *bitmap_bh = NULL; | |
1691 | ||
617ba13b | 1692 | es = EXT4_SB(sb)->s_es; |
ac27a0ec DK |
1693 | desc_count = 0; |
1694 | bitmap_count = 0; | |
1695 | gdp = NULL; | |
1696 | ||
1697 | smp_rmb(); | |
1698 | for (i = 0; i < ngroups; i++) { | |
617ba13b | 1699 | gdp = ext4_get_group_desc(sb, i, NULL); |
ac27a0ec DK |
1700 | if (!gdp) |
1701 | continue; | |
1702 | desc_count += le16_to_cpu(gdp->bg_free_blocks_count); | |
1703 | brelse(bitmap_bh); | |
1704 | bitmap_bh = read_block_bitmap(sb, i); | |
1705 | if (bitmap_bh == NULL) | |
1706 | continue; | |
1707 | ||
617ba13b | 1708 | x = ext4_count_free(bitmap_bh, sb->s_blocksize); |
ac27a0ec DK |
1709 | printk("group %d: stored = %d, counted = %lu\n", |
1710 | i, le16_to_cpu(gdp->bg_free_blocks_count), x); | |
1711 | bitmap_count += x; | |
1712 | } | |
1713 | brelse(bitmap_bh); | |
617ba13b | 1714 | printk("ext4_count_free_blocks: stored = "E3FSBLK |
ac27a0ec DK |
1715 | ", computed = "E3FSBLK", "E3FSBLK"\n", |
1716 | le32_to_cpu(es->s_free_blocks_count), | |
1717 | desc_count, bitmap_count); | |
1718 | return bitmap_count; | |
1719 | #else | |
1720 | desc_count = 0; | |
1721 | smp_rmb(); | |
1722 | for (i = 0; i < ngroups; i++) { | |
617ba13b | 1723 | gdp = ext4_get_group_desc(sb, i, NULL); |
ac27a0ec DK |
1724 | if (!gdp) |
1725 | continue; | |
1726 | desc_count += le16_to_cpu(gdp->bg_free_blocks_count); | |
1727 | } | |
1728 | ||
1729 | return desc_count; | |
1730 | #endif | |
1731 | } | |
1732 | ||
1733 | static inline int | |
617ba13b | 1734 | block_in_use(ext4_fsblk_t block, struct super_block *sb, unsigned char *map) |
ac27a0ec | 1735 | { |
617ba13b MC |
1736 | return ext4_test_bit ((block - |
1737 | le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) % | |
1738 | EXT4_BLOCKS_PER_GROUP(sb), map); | |
ac27a0ec DK |
1739 | } |
1740 | ||
1741 | static inline int test_root(int a, int b) | |
1742 | { | |
1743 | int num = b; | |
1744 | ||
1745 | while (a > num) | |
1746 | num *= b; | |
1747 | return num == a; | |
1748 | } | |
1749 | ||
617ba13b | 1750 | static int ext4_group_sparse(int group) |
ac27a0ec DK |
1751 | { |
1752 | if (group <= 1) | |
1753 | return 1; | |
1754 | if (!(group & 1)) | |
1755 | return 0; | |
1756 | return (test_root(group, 7) || test_root(group, 5) || | |
1757 | test_root(group, 3)); | |
1758 | } | |
1759 | ||
1760 | /** | |
617ba13b | 1761 | * ext4_bg_has_super - number of blocks used by the superblock in group |
ac27a0ec DK |
1762 | * @sb: superblock for filesystem |
1763 | * @group: group number to check | |
1764 | * | |
1765 | * Return the number of blocks used by the superblock (primary or backup) | |
1766 | * in this group. Currently this will be only 0 or 1. | |
1767 | */ | |
617ba13b | 1768 | int ext4_bg_has_super(struct super_block *sb, int group) |
ac27a0ec | 1769 | { |
617ba13b MC |
1770 | if (EXT4_HAS_RO_COMPAT_FEATURE(sb, |
1771 | EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER) && | |
1772 | !ext4_group_sparse(group)) | |
ac27a0ec DK |
1773 | return 0; |
1774 | return 1; | |
1775 | } | |
1776 | ||
617ba13b | 1777 | static unsigned long ext4_bg_num_gdb_meta(struct super_block *sb, int group) |
ac27a0ec | 1778 | { |
617ba13b MC |
1779 | unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); |
1780 | unsigned long first = metagroup * EXT4_DESC_PER_BLOCK(sb); | |
1781 | unsigned long last = first + EXT4_DESC_PER_BLOCK(sb) - 1; | |
ac27a0ec DK |
1782 | |
1783 | if (group == first || group == first + 1 || group == last) | |
1784 | return 1; | |
1785 | return 0; | |
1786 | } | |
1787 | ||
617ba13b | 1788 | static unsigned long ext4_bg_num_gdb_nometa(struct super_block *sb, int group) |
ac27a0ec | 1789 | { |
617ba13b MC |
1790 | if (EXT4_HAS_RO_COMPAT_FEATURE(sb, |
1791 | EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER) && | |
1792 | !ext4_group_sparse(group)) | |
ac27a0ec | 1793 | return 0; |
617ba13b | 1794 | return EXT4_SB(sb)->s_gdb_count; |
ac27a0ec DK |
1795 | } |
1796 | ||
1797 | /** | |
617ba13b | 1798 | * ext4_bg_num_gdb - number of blocks used by the group table in group |
ac27a0ec DK |
1799 | * @sb: superblock for filesystem |
1800 | * @group: group number to check | |
1801 | * | |
1802 | * Return the number of blocks used by the group descriptor table | |
1803 | * (primary or backup) in this group. In the future there may be a | |
1804 | * different number of descriptor blocks in each group. | |
1805 | */ | |
617ba13b | 1806 | unsigned long ext4_bg_num_gdb(struct super_block *sb, int group) |
ac27a0ec DK |
1807 | { |
1808 | unsigned long first_meta_bg = | |
617ba13b MC |
1809 | le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg); |
1810 | unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); | |
ac27a0ec | 1811 | |
617ba13b | 1812 | if (!EXT4_HAS_INCOMPAT_FEATURE(sb,EXT4_FEATURE_INCOMPAT_META_BG) || |
ac27a0ec | 1813 | metagroup < first_meta_bg) |
617ba13b | 1814 | return ext4_bg_num_gdb_nometa(sb,group); |
ac27a0ec | 1815 | |
617ba13b | 1816 | return ext4_bg_num_gdb_meta(sb,group); |
ac27a0ec DK |
1817 | |
1818 | } |