Commit | Line | Data |
---|---|---|
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> | |
dab291af | 17 | #include <linux/jbd2.h> |
617ba13b | 18 | #include <linux/ext4_fs.h> |
dab291af | 19 | #include <linux/ext4_jbd2.h> |
ac27a0ec DK |
20 | #include <linux/quotaops.h> |
21 | #include <linux/buffer_head.h> | |
22 | ||
717d50e4 | 23 | #include "group.h" |
ac27a0ec DK |
24 | /* |
25 | * balloc.c contains the blocks allocation and deallocation routines | |
26 | */ | |
27 | ||
72b64b59 AM |
28 | /* |
29 | * Calculate the block group number and offset, given a block number | |
30 | */ | |
31 | void ext4_get_group_no_and_offset(struct super_block *sb, ext4_fsblk_t blocknr, | |
fd2d4291 | 32 | ext4_group_t *blockgrpp, ext4_grpblk_t *offsetp) |
72b64b59 | 33 | { |
8c55e204 | 34 | struct ext4_super_block *es = EXT4_SB(sb)->s_es; |
72b64b59 AM |
35 | ext4_grpblk_t offset; |
36 | ||
8c55e204 | 37 | blocknr = blocknr - le32_to_cpu(es->s_first_data_block); |
f4e5bc24 | 38 | offset = do_div(blocknr, EXT4_BLOCKS_PER_GROUP(sb)); |
72b64b59 AM |
39 | if (offsetp) |
40 | *offsetp = offset; | |
41 | if (blockgrpp) | |
8c55e204 | 42 | *blockgrpp = blocknr; |
72b64b59 AM |
43 | |
44 | } | |
45 | ||
717d50e4 AD |
46 | /* Initializes an uninitialized block bitmap if given, and returns the |
47 | * number of blocks free in the group. */ | |
48 | unsigned ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh, | |
fd2d4291 | 49 | ext4_group_t block_group, struct ext4_group_desc *gdp) |
717d50e4 AD |
50 | { |
51 | unsigned long start; | |
52 | int bit, bit_max; | |
53 | unsigned free_blocks, group_blocks; | |
54 | struct ext4_sb_info *sbi = EXT4_SB(sb); | |
55 | ||
56 | if (bh) { | |
57 | J_ASSERT_BH(bh, buffer_locked(bh)); | |
58 | ||
59 | /* If checksum is bad mark all blocks used to prevent allocation | |
60 | * essentially implementing a per-group read-only flag. */ | |
61 | if (!ext4_group_desc_csum_verify(sbi, block_group, gdp)) { | |
62 | ext4_error(sb, __FUNCTION__, | |
fd2d4291 | 63 | "Checksum bad for group %lu\n", block_group); |
717d50e4 AD |
64 | gdp->bg_free_blocks_count = 0; |
65 | gdp->bg_free_inodes_count = 0; | |
66 | gdp->bg_itable_unused = 0; | |
67 | memset(bh->b_data, 0xff, sb->s_blocksize); | |
68 | return 0; | |
69 | } | |
70 | memset(bh->b_data, 0, sb->s_blocksize); | |
71 | } | |
72 | ||
73 | /* Check for superblock and gdt backups in this group */ | |
74 | bit_max = ext4_bg_has_super(sb, block_group); | |
75 | ||
76 | if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG) || | |
77 | block_group < le32_to_cpu(sbi->s_es->s_first_meta_bg) * | |
78 | sbi->s_desc_per_block) { | |
79 | if (bit_max) { | |
80 | bit_max += ext4_bg_num_gdb(sb, block_group); | |
81 | bit_max += | |
82 | le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks); | |
83 | } | |
84 | } else { /* For META_BG_BLOCK_GROUPS */ | |
85 | int group_rel = (block_group - | |
86 | le32_to_cpu(sbi->s_es->s_first_meta_bg)) % | |
87 | EXT4_DESC_PER_BLOCK(sb); | |
88 | if (group_rel == 0 || group_rel == 1 || | |
89 | (group_rel == EXT4_DESC_PER_BLOCK(sb) - 1)) | |
90 | bit_max += 1; | |
91 | } | |
92 | ||
93 | if (block_group == sbi->s_groups_count - 1) { | |
94 | /* | |
95 | * Even though mke2fs always initialize first and last group | |
96 | * if some other tool enabled the EXT4_BG_BLOCK_UNINIT we need | |
97 | * to make sure we calculate the right free blocks | |
98 | */ | |
99 | group_blocks = ext4_blocks_count(sbi->s_es) - | |
100 | le32_to_cpu(sbi->s_es->s_first_data_block) - | |
101 | (EXT4_BLOCKS_PER_GROUP(sb) * (sbi->s_groups_count -1)); | |
102 | } else { | |
103 | group_blocks = EXT4_BLOCKS_PER_GROUP(sb); | |
104 | } | |
105 | ||
106 | free_blocks = group_blocks - bit_max; | |
107 | ||
108 | if (bh) { | |
109 | for (bit = 0; bit < bit_max; bit++) | |
110 | ext4_set_bit(bit, bh->b_data); | |
111 | ||
112 | start = block_group * EXT4_BLOCKS_PER_GROUP(sb) + | |
113 | le32_to_cpu(sbi->s_es->s_first_data_block); | |
114 | ||
115 | /* Set bits for block and inode bitmaps, and inode table */ | |
116 | ext4_set_bit(ext4_block_bitmap(sb, gdp) - start, bh->b_data); | |
117 | ext4_set_bit(ext4_inode_bitmap(sb, gdp) - start, bh->b_data); | |
5272f837 | 118 | for (bit = (ext4_inode_table(sb, gdp) - start), |
717d50e4 AD |
119 | bit_max = bit + sbi->s_itb_per_group; bit < bit_max; bit++) |
120 | ext4_set_bit(bit, bh->b_data); | |
121 | ||
122 | /* | |
123 | * Also if the number of blocks within the group is | |
124 | * less than the blocksize * 8 ( which is the size | |
125 | * of bitmap ), set rest of the block bitmap to 1 | |
126 | */ | |
127 | mark_bitmap_end(group_blocks, sb->s_blocksize * 8, bh->b_data); | |
128 | } | |
129 | ||
130 | return free_blocks - sbi->s_itb_per_group - 2; | |
131 | } | |
132 | ||
133 | ||
ac27a0ec DK |
134 | /* |
135 | * The free blocks are managed by bitmaps. A file system contains several | |
136 | * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap | |
137 | * block for inodes, N blocks for the inode table and data blocks. | |
138 | * | |
139 | * The file system contains group descriptors which are located after the | |
140 | * super block. Each descriptor contains the number of the bitmap block and | |
141 | * the free blocks count in the block. The descriptors are loaded in memory | |
e627432c | 142 | * when a file system is mounted (see ext4_fill_super). |
ac27a0ec DK |
143 | */ |
144 | ||
145 | ||
146 | #define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1) | |
147 | ||
148 | /** | |
617ba13b | 149 | * ext4_get_group_desc() -- load group descriptor from disk |
ac27a0ec DK |
150 | * @sb: super block |
151 | * @block_group: given block group | |
152 | * @bh: pointer to the buffer head to store the block | |
153 | * group descriptor | |
154 | */ | |
617ba13b | 155 | struct ext4_group_desc * ext4_get_group_desc(struct super_block * sb, |
fd2d4291 | 156 | ext4_group_t block_group, |
ac27a0ec DK |
157 | struct buffer_head ** bh) |
158 | { | |
159 | unsigned long group_desc; | |
160 | unsigned long offset; | |
617ba13b MC |
161 | struct ext4_group_desc * desc; |
162 | struct ext4_sb_info *sbi = EXT4_SB(sb); | |
ac27a0ec DK |
163 | |
164 | if (block_group >= sbi->s_groups_count) { | |
617ba13b | 165 | ext4_error (sb, "ext4_get_group_desc", |
ac27a0ec | 166 | "block_group >= groups_count - " |
fd2d4291 | 167 | "block_group = %lu, groups_count = %lu", |
ac27a0ec DK |
168 | block_group, sbi->s_groups_count); |
169 | ||
170 | return NULL; | |
171 | } | |
172 | smp_rmb(); | |
173 | ||
617ba13b MC |
174 | group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb); |
175 | offset = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1); | |
ac27a0ec | 176 | if (!sbi->s_group_desc[group_desc]) { |
617ba13b | 177 | ext4_error (sb, "ext4_get_group_desc", |
ac27a0ec | 178 | "Group descriptor not loaded - " |
fd2d4291 | 179 | "block_group = %lu, group_desc = %lu, desc = %lu", |
ac27a0ec DK |
180 | block_group, group_desc, offset); |
181 | return NULL; | |
182 | } | |
183 | ||
0d1ee42f AR |
184 | desc = (struct ext4_group_desc *)( |
185 | (__u8 *)sbi->s_group_desc[group_desc]->b_data + | |
186 | offset * EXT4_DESC_SIZE(sb)); | |
ac27a0ec DK |
187 | if (bh) |
188 | *bh = sbi->s_group_desc[group_desc]; | |
0d1ee42f | 189 | return desc; |
ac27a0ec DK |
190 | } |
191 | ||
abcb2947 AK |
192 | static int ext4_valid_block_bitmap(struct super_block *sb, |
193 | struct ext4_group_desc *desc, | |
194 | unsigned int block_group, | |
195 | struct buffer_head *bh) | |
196 | { | |
197 | ext4_grpblk_t offset; | |
198 | ext4_grpblk_t next_zero_bit; | |
199 | ext4_fsblk_t bitmap_blk; | |
200 | ext4_fsblk_t group_first_block; | |
201 | ||
202 | if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG)) { | |
203 | /* with FLEX_BG, the inode/block bitmaps and itable | |
204 | * blocks may not be in the group at all | |
205 | * so the bitmap validation will be skipped for those groups | |
206 | * or it has to also read the block group where the bitmaps | |
207 | * are located to verify they are set. | |
208 | */ | |
209 | return 1; | |
210 | } | |
211 | group_first_block = ext4_group_first_block_no(sb, block_group); | |
212 | ||
213 | /* check whether block bitmap block number is set */ | |
214 | bitmap_blk = ext4_block_bitmap(sb, desc); | |
215 | offset = bitmap_blk - group_first_block; | |
216 | if (!ext4_test_bit(offset, bh->b_data)) | |
217 | /* bad block bitmap */ | |
218 | goto err_out; | |
219 | ||
220 | /* check whether the inode bitmap block number is set */ | |
221 | bitmap_blk = ext4_inode_bitmap(sb, desc); | |
222 | offset = bitmap_blk - group_first_block; | |
223 | if (!ext4_test_bit(offset, bh->b_data)) | |
224 | /* bad block bitmap */ | |
225 | goto err_out; | |
226 | ||
227 | /* check whether the inode table block number is set */ | |
228 | bitmap_blk = ext4_inode_table(sb, desc); | |
229 | offset = bitmap_blk - group_first_block; | |
230 | next_zero_bit = ext4_find_next_zero_bit(bh->b_data, | |
231 | offset + EXT4_SB(sb)->s_itb_per_group, | |
232 | offset); | |
233 | if (next_zero_bit >= offset + EXT4_SB(sb)->s_itb_per_group) | |
234 | /* good bitmap for inode tables */ | |
235 | return 1; | |
236 | ||
237 | err_out: | |
238 | ext4_error(sb, __FUNCTION__, | |
239 | "Invalid block bitmap - " | |
240 | "block_group = %d, block = %llu", | |
241 | block_group, bitmap_blk); | |
242 | return 0; | |
243 | } | |
ac27a0ec DK |
244 | /** |
245 | * read_block_bitmap() | |
246 | * @sb: super block | |
247 | * @block_group: given block group | |
248 | * | |
abcb2947 AK |
249 | * Read the bitmap for a given block_group,and validate the |
250 | * bits for block/inode/inode tables are set in the bitmaps | |
ac27a0ec DK |
251 | * |
252 | * Return buffer_head on success or NULL in case of failure. | |
253 | */ | |
717d50e4 | 254 | struct buffer_head * |
fd2d4291 | 255 | read_block_bitmap(struct super_block *sb, ext4_group_t block_group) |
ac27a0ec | 256 | { |
617ba13b | 257 | struct ext4_group_desc * desc; |
ac27a0ec | 258 | struct buffer_head * bh = NULL; |
7c9e69fa | 259 | ext4_fsblk_t bitmap_blk; |
ac27a0ec | 260 | |
717d50e4 | 261 | desc = ext4_get_group_desc(sb, block_group, NULL); |
ac27a0ec | 262 | if (!desc) |
7c9e69fa AK |
263 | return NULL; |
264 | bitmap_blk = ext4_block_bitmap(sb, desc); | |
abcb2947 AK |
265 | bh = sb_getblk(sb, bitmap_blk); |
266 | if (unlikely(!bh)) { | |
267 | ext4_error(sb, __FUNCTION__, | |
268 | "Cannot read block bitmap - " | |
269 | "block_group = %d, block_bitmap = %llu", | |
270 | (int)block_group, (unsigned long long)bitmap_blk); | |
271 | return NULL; | |
272 | } | |
273 | if (bh_uptodate_or_lock(bh)) | |
274 | return bh; | |
275 | ||
717d50e4 | 276 | if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) { |
abcb2947 AK |
277 | ext4_init_block_bitmap(sb, bh, block_group, desc); |
278 | set_buffer_uptodate(bh); | |
279 | unlock_buffer(bh); | |
280 | return bh; | |
717d50e4 | 281 | } |
abcb2947 AK |
282 | if (bh_submit_read(bh) < 0) { |
283 | put_bh(bh); | |
284 | ext4_error(sb, __FUNCTION__, | |
ac27a0ec | 285 | "Cannot read block bitmap - " |
abcb2947 AK |
286 | "block_group = %d, block_bitmap = %llu", |
287 | (int)block_group, (unsigned long long)bitmap_blk); | |
288 | return NULL; | |
289 | } | |
290 | if (!ext4_valid_block_bitmap(sb, desc, block_group, bh)) { | |
291 | put_bh(bh); | |
292 | return NULL; | |
293 | } | |
294 | ||
ac27a0ec DK |
295 | return bh; |
296 | } | |
297 | /* | |
298 | * The reservation window structure operations | |
299 | * -------------------------------------------- | |
300 | * Operations include: | |
301 | * dump, find, add, remove, is_empty, find_next_reservable_window, etc. | |
302 | * | |
303 | * We use a red-black tree to represent per-filesystem reservation | |
304 | * windows. | |
305 | * | |
306 | */ | |
307 | ||
308 | /** | |
309 | * __rsv_window_dump() -- Dump the filesystem block allocation reservation map | |
310 | * @rb_root: root of per-filesystem reservation rb tree | |
311 | * @verbose: verbose mode | |
312 | * @fn: function which wishes to dump the reservation map | |
313 | * | |
314 | * If verbose is turned on, it will print the whole block reservation | |
315 | * windows(start, end). Otherwise, it will only print out the "bad" windows, | |
316 | * those windows that overlap with their immediate neighbors. | |
317 | */ | |
318 | #if 1 | |
319 | static void __rsv_window_dump(struct rb_root *root, int verbose, | |
320 | const char *fn) | |
321 | { | |
322 | struct rb_node *n; | |
617ba13b | 323 | struct ext4_reserve_window_node *rsv, *prev; |
ac27a0ec DK |
324 | int bad; |
325 | ||
326 | restart: | |
327 | n = rb_first(root); | |
328 | bad = 0; | |
329 | prev = NULL; | |
330 | ||
331 | printk("Block Allocation Reservation Windows Map (%s):\n", fn); | |
332 | while (n) { | |
b78a657f | 333 | rsv = rb_entry(n, struct ext4_reserve_window_node, rsv_node); |
ac27a0ec DK |
334 | if (verbose) |
335 | printk("reservation window 0x%p " | |
2ae02107 | 336 | "start: %llu, end: %llu\n", |
ac27a0ec DK |
337 | rsv, rsv->rsv_start, rsv->rsv_end); |
338 | if (rsv->rsv_start && rsv->rsv_start >= rsv->rsv_end) { | |
339 | printk("Bad reservation %p (start >= end)\n", | |
340 | rsv); | |
341 | bad = 1; | |
342 | } | |
343 | if (prev && prev->rsv_end >= rsv->rsv_start) { | |
344 | printk("Bad reservation %p (prev->end >= start)\n", | |
345 | rsv); | |
346 | bad = 1; | |
347 | } | |
348 | if (bad) { | |
349 | if (!verbose) { | |
350 | printk("Restarting reservation walk in verbose mode\n"); | |
351 | verbose = 1; | |
352 | goto restart; | |
353 | } | |
354 | } | |
355 | n = rb_next(n); | |
356 | prev = rsv; | |
357 | } | |
358 | printk("Window map complete.\n"); | |
359 | if (bad) | |
360 | BUG(); | |
361 | } | |
362 | #define rsv_window_dump(root, verbose) \ | |
363 | __rsv_window_dump((root), (verbose), __FUNCTION__) | |
364 | #else | |
365 | #define rsv_window_dump(root, verbose) do {} while (0) | |
366 | #endif | |
367 | ||
368 | /** | |
369 | * goal_in_my_reservation() | |
370 | * @rsv: inode's reservation window | |
371 | * @grp_goal: given goal block relative to the allocation block group | |
372 | * @group: the current allocation block group | |
373 | * @sb: filesystem super block | |
374 | * | |
375 | * Test if the given goal block (group relative) is within the file's | |
376 | * own block reservation window range. | |
377 | * | |
378 | * If the reservation window is outside the goal allocation group, return 0; | |
379 | * grp_goal (given goal block) could be -1, which means no specific | |
380 | * goal block. In this case, always return 1. | |
381 | * If the goal block is within the reservation window, return 1; | |
382 | * otherwise, return 0; | |
383 | */ | |
384 | static int | |
617ba13b | 385 | goal_in_my_reservation(struct ext4_reserve_window *rsv, ext4_grpblk_t grp_goal, |
fd2d4291 | 386 | ext4_group_t group, struct super_block *sb) |
ac27a0ec | 387 | { |
617ba13b | 388 | ext4_fsblk_t group_first_block, group_last_block; |
ac27a0ec | 389 | |
617ba13b MC |
390 | group_first_block = ext4_group_first_block_no(sb, group); |
391 | group_last_block = group_first_block + (EXT4_BLOCKS_PER_GROUP(sb) - 1); | |
ac27a0ec DK |
392 | |
393 | if ((rsv->_rsv_start > group_last_block) || | |
394 | (rsv->_rsv_end < group_first_block)) | |
395 | return 0; | |
396 | if ((grp_goal >= 0) && ((grp_goal + group_first_block < rsv->_rsv_start) | |
397 | || (grp_goal + group_first_block > rsv->_rsv_end))) | |
398 | return 0; | |
399 | return 1; | |
400 | } | |
401 | ||
402 | /** | |
403 | * search_reserve_window() | |
404 | * @rb_root: root of reservation tree | |
405 | * @goal: target allocation block | |
406 | * | |
407 | * Find the reserved window which includes the goal, or the previous one | |
408 | * if the goal is not in any window. | |
409 | * Returns NULL if there are no windows or if all windows start after the goal. | |
410 | */ | |
617ba13b MC |
411 | static struct ext4_reserve_window_node * |
412 | search_reserve_window(struct rb_root *root, ext4_fsblk_t goal) | |
ac27a0ec DK |
413 | { |
414 | struct rb_node *n = root->rb_node; | |
617ba13b | 415 | struct ext4_reserve_window_node *rsv; |
ac27a0ec DK |
416 | |
417 | if (!n) | |
418 | return NULL; | |
419 | ||
420 | do { | |
617ba13b | 421 | rsv = rb_entry(n, struct ext4_reserve_window_node, rsv_node); |
ac27a0ec DK |
422 | |
423 | if (goal < rsv->rsv_start) | |
424 | n = n->rb_left; | |
425 | else if (goal > rsv->rsv_end) | |
426 | n = n->rb_right; | |
427 | else | |
428 | return rsv; | |
429 | } while (n); | |
430 | /* | |
431 | * We've fallen off the end of the tree: the goal wasn't inside | |
432 | * any particular node. OK, the previous node must be to one | |
433 | * side of the interval containing the goal. If it's the RHS, | |
434 | * we need to back up one. | |
435 | */ | |
436 | if (rsv->rsv_start > goal) { | |
437 | n = rb_prev(&rsv->rsv_node); | |
617ba13b | 438 | rsv = rb_entry(n, struct ext4_reserve_window_node, rsv_node); |
ac27a0ec DK |
439 | } |
440 | return rsv; | |
441 | } | |
442 | ||
443 | /** | |
617ba13b | 444 | * ext4_rsv_window_add() -- Insert a window to the block reservation rb tree. |
ac27a0ec DK |
445 | * @sb: super block |
446 | * @rsv: reservation window to add | |
447 | * | |
448 | * Must be called with rsv_lock hold. | |
449 | */ | |
617ba13b MC |
450 | void ext4_rsv_window_add(struct super_block *sb, |
451 | struct ext4_reserve_window_node *rsv) | |
ac27a0ec | 452 | { |
617ba13b | 453 | struct rb_root *root = &EXT4_SB(sb)->s_rsv_window_root; |
ac27a0ec | 454 | struct rb_node *node = &rsv->rsv_node; |
617ba13b | 455 | ext4_fsblk_t start = rsv->rsv_start; |
ac27a0ec DK |
456 | |
457 | struct rb_node ** p = &root->rb_node; | |
458 | struct rb_node * parent = NULL; | |
617ba13b | 459 | struct ext4_reserve_window_node *this; |
ac27a0ec DK |
460 | |
461 | while (*p) | |
462 | { | |
463 | parent = *p; | |
617ba13b | 464 | this = rb_entry(parent, struct ext4_reserve_window_node, rsv_node); |
ac27a0ec DK |
465 | |
466 | if (start < this->rsv_start) | |
467 | p = &(*p)->rb_left; | |
468 | else if (start > this->rsv_end) | |
469 | p = &(*p)->rb_right; | |
470 | else { | |
471 | rsv_window_dump(root, 1); | |
472 | BUG(); | |
473 | } | |
474 | } | |
475 | ||
476 | rb_link_node(node, parent, p); | |
477 | rb_insert_color(node, root); | |
478 | } | |
479 | ||
480 | /** | |
617ba13b | 481 | * ext4_rsv_window_remove() -- unlink a window from the reservation rb tree |
ac27a0ec DK |
482 | * @sb: super block |
483 | * @rsv: reservation window to remove | |
484 | * | |
485 | * Mark the block reservation window as not allocated, and unlink it | |
486 | * from the filesystem reservation window rb tree. Must be called with | |
487 | * rsv_lock hold. | |
488 | */ | |
489 | static void rsv_window_remove(struct super_block *sb, | |
617ba13b | 490 | struct ext4_reserve_window_node *rsv) |
ac27a0ec | 491 | { |
617ba13b MC |
492 | rsv->rsv_start = EXT4_RESERVE_WINDOW_NOT_ALLOCATED; |
493 | rsv->rsv_end = EXT4_RESERVE_WINDOW_NOT_ALLOCATED; | |
ac27a0ec | 494 | rsv->rsv_alloc_hit = 0; |
617ba13b | 495 | rb_erase(&rsv->rsv_node, &EXT4_SB(sb)->s_rsv_window_root); |
ac27a0ec DK |
496 | } |
497 | ||
498 | /* | |
499 | * rsv_is_empty() -- Check if the reservation window is allocated. | |
500 | * @rsv: given reservation window to check | |
501 | * | |
617ba13b | 502 | * returns 1 if the end block is EXT4_RESERVE_WINDOW_NOT_ALLOCATED. |
ac27a0ec | 503 | */ |
617ba13b | 504 | static inline int rsv_is_empty(struct ext4_reserve_window *rsv) |
ac27a0ec DK |
505 | { |
506 | /* a valid reservation end block could not be 0 */ | |
617ba13b | 507 | return rsv->_rsv_end == EXT4_RESERVE_WINDOW_NOT_ALLOCATED; |
ac27a0ec DK |
508 | } |
509 | ||
510 | /** | |
617ba13b | 511 | * ext4_init_block_alloc_info() |
ac27a0ec DK |
512 | * @inode: file inode structure |
513 | * | |
514 | * Allocate and initialize the reservation window structure, and | |
617ba13b | 515 | * link the window to the ext4 inode structure at last |
ac27a0ec DK |
516 | * |
517 | * The reservation window structure is only dynamically allocated | |
617ba13b MC |
518 | * and linked to ext4 inode the first time the open file |
519 | * needs a new block. So, before every ext4_new_block(s) call, for | |
ac27a0ec DK |
520 | * regular files, we should check whether the reservation window |
521 | * structure exists or not. In the latter case, this function is called. | |
522 | * Fail to do so will result in block reservation being turned off for that | |
523 | * open file. | |
524 | * | |
617ba13b | 525 | * This function is called from ext4_get_blocks_handle(), also called |
ac27a0ec DK |
526 | * when setting the reservation window size through ioctl before the file |
527 | * is open for write (needs block allocation). | |
528 | * | |
0e855ac8 | 529 | * Needs down_write(i_data_sem) protection prior to call this function. |
ac27a0ec | 530 | */ |
617ba13b | 531 | void ext4_init_block_alloc_info(struct inode *inode) |
ac27a0ec | 532 | { |
617ba13b MC |
533 | struct ext4_inode_info *ei = EXT4_I(inode); |
534 | struct ext4_block_alloc_info *block_i = ei->i_block_alloc_info; | |
ac27a0ec DK |
535 | struct super_block *sb = inode->i_sb; |
536 | ||
537 | block_i = kmalloc(sizeof(*block_i), GFP_NOFS); | |
538 | if (block_i) { | |
617ba13b | 539 | struct ext4_reserve_window_node *rsv = &block_i->rsv_window_node; |
ac27a0ec | 540 | |
617ba13b MC |
541 | rsv->rsv_start = EXT4_RESERVE_WINDOW_NOT_ALLOCATED; |
542 | rsv->rsv_end = EXT4_RESERVE_WINDOW_NOT_ALLOCATED; | |
ac27a0ec DK |
543 | |
544 | /* | |
545 | * if filesystem is mounted with NORESERVATION, the goal | |
546 | * reservation window size is set to zero to indicate | |
547 | * block reservation is off | |
548 | */ | |
549 | if (!test_opt(sb, RESERVATION)) | |
550 | rsv->rsv_goal_size = 0; | |
551 | else | |
617ba13b | 552 | rsv->rsv_goal_size = EXT4_DEFAULT_RESERVE_BLOCKS; |
ac27a0ec DK |
553 | rsv->rsv_alloc_hit = 0; |
554 | block_i->last_alloc_logical_block = 0; | |
555 | block_i->last_alloc_physical_block = 0; | |
556 | } | |
557 | ei->i_block_alloc_info = block_i; | |
558 | } | |
559 | ||
560 | /** | |
617ba13b | 561 | * ext4_discard_reservation() |
ac27a0ec DK |
562 | * @inode: inode |
563 | * | |
564 | * Discard(free) block reservation window on last file close, or truncate | |
565 | * or at last iput(). | |
566 | * | |
567 | * It is being called in three cases: | |
617ba13b MC |
568 | * ext4_release_file(): last writer close the file |
569 | * ext4_clear_inode(): last iput(), when nobody link to this file. | |
570 | * ext4_truncate(): when the block indirect map is about to change. | |
ac27a0ec DK |
571 | * |
572 | */ | |
617ba13b | 573 | void ext4_discard_reservation(struct inode *inode) |
ac27a0ec | 574 | { |
617ba13b MC |
575 | struct ext4_inode_info *ei = EXT4_I(inode); |
576 | struct ext4_block_alloc_info *block_i = ei->i_block_alloc_info; | |
577 | struct ext4_reserve_window_node *rsv; | |
578 | spinlock_t *rsv_lock = &EXT4_SB(inode->i_sb)->s_rsv_window_lock; | |
ac27a0ec | 579 | |
c9de560d AT |
580 | ext4_mb_discard_inode_preallocations(inode); |
581 | ||
ac27a0ec DK |
582 | if (!block_i) |
583 | return; | |
584 | ||
585 | rsv = &block_i->rsv_window_node; | |
586 | if (!rsv_is_empty(&rsv->rsv_window)) { | |
587 | spin_lock(rsv_lock); | |
588 | if (!rsv_is_empty(&rsv->rsv_window)) | |
589 | rsv_window_remove(inode->i_sb, rsv); | |
590 | spin_unlock(rsv_lock); | |
591 | } | |
592 | } | |
593 | ||
594 | /** | |
617ba13b | 595 | * ext4_free_blocks_sb() -- Free given blocks and update quota |
ac27a0ec DK |
596 | * @handle: handle to this transaction |
597 | * @sb: super block | |
598 | * @block: start physcial block to free | |
599 | * @count: number of blocks to free | |
600 | * @pdquot_freed_blocks: pointer to quota | |
601 | */ | |
617ba13b MC |
602 | void ext4_free_blocks_sb(handle_t *handle, struct super_block *sb, |
603 | ext4_fsblk_t block, unsigned long count, | |
ac27a0ec DK |
604 | unsigned long *pdquot_freed_blocks) |
605 | { | |
606 | struct buffer_head *bitmap_bh = NULL; | |
607 | struct buffer_head *gd_bh; | |
fd2d4291 | 608 | ext4_group_t block_group; |
617ba13b | 609 | ext4_grpblk_t bit; |
ac27a0ec DK |
610 | unsigned long i; |
611 | unsigned long overflow; | |
617ba13b MC |
612 | struct ext4_group_desc * desc; |
613 | struct ext4_super_block * es; | |
614 | struct ext4_sb_info *sbi; | |
ac27a0ec | 615 | int err = 0, ret; |
617ba13b | 616 | ext4_grpblk_t group_freed; |
ac27a0ec DK |
617 | |
618 | *pdquot_freed_blocks = 0; | |
617ba13b | 619 | sbi = EXT4_SB(sb); |
ac27a0ec DK |
620 | es = sbi->s_es; |
621 | if (block < le32_to_cpu(es->s_first_data_block) || | |
622 | block + count < block || | |
bd81d8ee | 623 | block + count > ext4_blocks_count(es)) { |
617ba13b | 624 | ext4_error (sb, "ext4_free_blocks", |
ac27a0ec | 625 | "Freeing blocks not in datazone - " |
2ae02107 | 626 | "block = %llu, count = %lu", block, count); |
ac27a0ec DK |
627 | goto error_return; |
628 | } | |
629 | ||
bd81d8ee | 630 | ext4_debug ("freeing block(s) %llu-%llu\n", block, block + count - 1); |
ac27a0ec DK |
631 | |
632 | do_more: | |
633 | overflow = 0; | |
3a5b2ecd | 634 | ext4_get_group_no_and_offset(sb, block, &block_group, &bit); |
ac27a0ec DK |
635 | /* |
636 | * Check to see if we are freeing blocks across a group | |
637 | * boundary. | |
638 | */ | |
617ba13b MC |
639 | if (bit + count > EXT4_BLOCKS_PER_GROUP(sb)) { |
640 | overflow = bit + count - EXT4_BLOCKS_PER_GROUP(sb); | |
ac27a0ec DK |
641 | count -= overflow; |
642 | } | |
643 | brelse(bitmap_bh); | |
644 | bitmap_bh = read_block_bitmap(sb, block_group); | |
645 | if (!bitmap_bh) | |
646 | goto error_return; | |
617ba13b | 647 | desc = ext4_get_group_desc (sb, block_group, &gd_bh); |
ac27a0ec DK |
648 | if (!desc) |
649 | goto error_return; | |
650 | ||
8fadc143 AR |
651 | if (in_range(ext4_block_bitmap(sb, desc), block, count) || |
652 | in_range(ext4_inode_bitmap(sb, desc), block, count) || | |
653 | in_range(block, ext4_inode_table(sb, desc), sbi->s_itb_per_group) || | |
654 | in_range(block + count - 1, ext4_inode_table(sb, desc), | |
cb47dce7 | 655 | sbi->s_itb_per_group)) { |
617ba13b | 656 | ext4_error (sb, "ext4_free_blocks", |
ac27a0ec | 657 | "Freeing blocks in system zones - " |
2ae02107 | 658 | "Block = %llu, count = %lu", |
ac27a0ec | 659 | block, count); |
cb47dce7 AK |
660 | goto error_return; |
661 | } | |
ac27a0ec DK |
662 | |
663 | /* | |
664 | * We are about to start releasing blocks in the bitmap, | |
665 | * so we need undo access. | |
666 | */ | |
667 | /* @@@ check errors */ | |
668 | BUFFER_TRACE(bitmap_bh, "getting undo access"); | |
617ba13b | 669 | err = ext4_journal_get_undo_access(handle, bitmap_bh); |
ac27a0ec DK |
670 | if (err) |
671 | goto error_return; | |
672 | ||
673 | /* | |
674 | * We are about to modify some metadata. Call the journal APIs | |
675 | * to unshare ->b_data if a currently-committing transaction is | |
676 | * using it | |
677 | */ | |
678 | BUFFER_TRACE(gd_bh, "get_write_access"); | |
617ba13b | 679 | err = ext4_journal_get_write_access(handle, gd_bh); |
ac27a0ec DK |
680 | if (err) |
681 | goto error_return; | |
682 | ||
683 | jbd_lock_bh_state(bitmap_bh); | |
684 | ||
685 | for (i = 0, group_freed = 0; i < count; i++) { | |
686 | /* | |
687 | * An HJ special. This is expensive... | |
688 | */ | |
e23291b9 | 689 | #ifdef CONFIG_JBD2_DEBUG |
ac27a0ec DK |
690 | jbd_unlock_bh_state(bitmap_bh); |
691 | { | |
692 | struct buffer_head *debug_bh; | |
693 | debug_bh = sb_find_get_block(sb, block + i); | |
694 | if (debug_bh) { | |
695 | BUFFER_TRACE(debug_bh, "Deleted!"); | |
696 | if (!bh2jh(bitmap_bh)->b_committed_data) | |
697 | BUFFER_TRACE(debug_bh, | |
698 | "No commited data in bitmap"); | |
699 | BUFFER_TRACE2(debug_bh, bitmap_bh, "bitmap"); | |
700 | __brelse(debug_bh); | |
701 | } | |
702 | } | |
703 | jbd_lock_bh_state(bitmap_bh); | |
704 | #endif | |
705 | if (need_resched()) { | |
706 | jbd_unlock_bh_state(bitmap_bh); | |
707 | cond_resched(); | |
708 | jbd_lock_bh_state(bitmap_bh); | |
709 | } | |
710 | /* @@@ This prevents newly-allocated data from being | |
711 | * freed and then reallocated within the same | |
712 | * transaction. | |
713 | * | |
714 | * Ideally we would want to allow that to happen, but to | |
dab291af | 715 | * do so requires making jbd2_journal_forget() capable of |
ac27a0ec DK |
716 | * revoking the queued write of a data block, which |
717 | * implies blocking on the journal lock. *forget() | |
718 | * cannot block due to truncate races. | |
719 | * | |
dab291af | 720 | * Eventually we can fix this by making jbd2_journal_forget() |
ac27a0ec DK |
721 | * return a status indicating whether or not it was able |
722 | * to revoke the buffer. On successful revoke, it is | |
723 | * safe not to set the allocation bit in the committed | |
724 | * bitmap, because we know that there is no outstanding | |
725 | * activity on the buffer any more and so it is safe to | |
726 | * reallocate it. | |
727 | */ | |
728 | BUFFER_TRACE(bitmap_bh, "set in b_committed_data"); | |
729 | J_ASSERT_BH(bitmap_bh, | |
730 | bh2jh(bitmap_bh)->b_committed_data != NULL); | |
617ba13b | 731 | ext4_set_bit_atomic(sb_bgl_lock(sbi, block_group), bit + i, |
ac27a0ec DK |
732 | bh2jh(bitmap_bh)->b_committed_data); |
733 | ||
734 | /* | |
735 | * We clear the bit in the bitmap after setting the committed | |
736 | * data bit, because this is the reverse order to that which | |
737 | * the allocator uses. | |
738 | */ | |
739 | BUFFER_TRACE(bitmap_bh, "clear bit"); | |
617ba13b | 740 | if (!ext4_clear_bit_atomic(sb_bgl_lock(sbi, block_group), |
ac27a0ec DK |
741 | bit + i, bitmap_bh->b_data)) { |
742 | jbd_unlock_bh_state(bitmap_bh); | |
617ba13b | 743 | ext4_error(sb, __FUNCTION__, |
2ae02107 | 744 | "bit already cleared for block %llu", |
bd81d8ee | 745 | (ext4_fsblk_t)(block + i)); |
ac27a0ec DK |
746 | jbd_lock_bh_state(bitmap_bh); |
747 | BUFFER_TRACE(bitmap_bh, "bit already cleared"); | |
748 | } else { | |
749 | group_freed++; | |
750 | } | |
751 | } | |
752 | jbd_unlock_bh_state(bitmap_bh); | |
753 | ||
754 | spin_lock(sb_bgl_lock(sbi, block_group)); | |
755 | desc->bg_free_blocks_count = | |
756 | cpu_to_le16(le16_to_cpu(desc->bg_free_blocks_count) + | |
757 | group_freed); | |
717d50e4 | 758 | desc->bg_checksum = ext4_group_desc_csum(sbi, block_group, desc); |
ac27a0ec | 759 | spin_unlock(sb_bgl_lock(sbi, block_group)); |
aa0dff2d | 760 | percpu_counter_add(&sbi->s_freeblocks_counter, count); |
ac27a0ec DK |
761 | |
762 | /* We dirtied the bitmap block */ | |
763 | BUFFER_TRACE(bitmap_bh, "dirtied bitmap block"); | |
617ba13b | 764 | err = ext4_journal_dirty_metadata(handle, bitmap_bh); |
ac27a0ec DK |
765 | |
766 | /* And the group descriptor block */ | |
767 | BUFFER_TRACE(gd_bh, "dirtied group descriptor block"); | |
617ba13b | 768 | ret = ext4_journal_dirty_metadata(handle, gd_bh); |
ac27a0ec DK |
769 | if (!err) err = ret; |
770 | *pdquot_freed_blocks += group_freed; | |
771 | ||
772 | if (overflow && !err) { | |
773 | block += count; | |
774 | count = overflow; | |
775 | goto do_more; | |
776 | } | |
777 | sb->s_dirt = 1; | |
778 | error_return: | |
779 | brelse(bitmap_bh); | |
617ba13b | 780 | ext4_std_error(sb, err); |
ac27a0ec DK |
781 | return; |
782 | } | |
783 | ||
784 | /** | |
617ba13b | 785 | * ext4_free_blocks() -- Free given blocks and update quota |
ac27a0ec DK |
786 | * @handle: handle for this transaction |
787 | * @inode: inode | |
788 | * @block: start physical block to free | |
789 | * @count: number of blocks to count | |
c9de560d | 790 | * @metadata: Are these metadata blocks |
ac27a0ec | 791 | */ |
617ba13b | 792 | void ext4_free_blocks(handle_t *handle, struct inode *inode, |
c9de560d AT |
793 | ext4_fsblk_t block, unsigned long count, |
794 | int metadata) | |
ac27a0ec DK |
795 | { |
796 | struct super_block * sb; | |
797 | unsigned long dquot_freed_blocks; | |
798 | ||
c9de560d AT |
799 | /* this isn't the right place to decide whether block is metadata |
800 | * inode.c/extents.c knows better, but for safety ... */ | |
801 | if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode) || | |
802 | ext4_should_journal_data(inode)) | |
803 | metadata = 1; | |
804 | ||
ac27a0ec | 805 | sb = inode->i_sb; |
c9de560d AT |
806 | |
807 | if (!test_opt(sb, MBALLOC) || !EXT4_SB(sb)->s_group_info) | |
808 | ext4_free_blocks_sb(handle, sb, block, count, | |
809 | &dquot_freed_blocks); | |
810 | else | |
811 | ext4_mb_free_blocks(handle, inode, block, count, | |
812 | metadata, &dquot_freed_blocks); | |
ac27a0ec DK |
813 | if (dquot_freed_blocks) |
814 | DQUOT_FREE_BLOCK(inode, dquot_freed_blocks); | |
815 | return; | |
816 | } | |
817 | ||
818 | /** | |
617ba13b | 819 | * ext4_test_allocatable() |
ac27a0ec DK |
820 | * @nr: given allocation block group |
821 | * @bh: bufferhead contains the bitmap of the given block group | |
822 | * | |
617ba13b | 823 | * For ext4 allocations, we must not reuse any blocks which are |
ac27a0ec DK |
824 | * allocated in the bitmap buffer's "last committed data" copy. This |
825 | * prevents deletes from freeing up the page for reuse until we have | |
826 | * committed the delete transaction. | |
827 | * | |
828 | * If we didn't do this, then deleting something and reallocating it as | |
829 | * data would allow the old block to be overwritten before the | |
830 | * transaction committed (because we force data to disk before commit). | |
831 | * This would lead to corruption if we crashed between overwriting the | |
832 | * data and committing the delete. | |
833 | * | |
834 | * @@@ We may want to make this allocation behaviour conditional on | |
835 | * data-writes at some point, and disable it for metadata allocations or | |
836 | * sync-data inodes. | |
837 | */ | |
617ba13b | 838 | static int ext4_test_allocatable(ext4_grpblk_t nr, struct buffer_head *bh) |
ac27a0ec DK |
839 | { |
840 | int ret; | |
841 | struct journal_head *jh = bh2jh(bh); | |
842 | ||
617ba13b | 843 | if (ext4_test_bit(nr, bh->b_data)) |
ac27a0ec DK |
844 | return 0; |
845 | ||
846 | jbd_lock_bh_state(bh); | |
847 | if (!jh->b_committed_data) | |
848 | ret = 1; | |
849 | else | |
617ba13b | 850 | ret = !ext4_test_bit(nr, jh->b_committed_data); |
ac27a0ec DK |
851 | jbd_unlock_bh_state(bh); |
852 | return ret; | |
853 | } | |
854 | ||
855 | /** | |
856 | * bitmap_search_next_usable_block() | |
857 | * @start: the starting block (group relative) of the search | |
858 | * @bh: bufferhead contains the block group bitmap | |
859 | * @maxblocks: the ending block (group relative) of the reservation | |
860 | * | |
861 | * The bitmap search --- search forward alternately through the actual | |
862 | * bitmap on disk and the last-committed copy in journal, until we find a | |
863 | * bit free in both bitmaps. | |
864 | */ | |
617ba13b MC |
865 | static ext4_grpblk_t |
866 | bitmap_search_next_usable_block(ext4_grpblk_t start, struct buffer_head *bh, | |
867 | ext4_grpblk_t maxblocks) | |
ac27a0ec | 868 | { |
617ba13b | 869 | ext4_grpblk_t next; |
ac27a0ec DK |
870 | struct journal_head *jh = bh2jh(bh); |
871 | ||
872 | while (start < maxblocks) { | |
617ba13b | 873 | next = ext4_find_next_zero_bit(bh->b_data, maxblocks, start); |
ac27a0ec DK |
874 | if (next >= maxblocks) |
875 | return -1; | |
617ba13b | 876 | if (ext4_test_allocatable(next, bh)) |
ac27a0ec DK |
877 | return next; |
878 | jbd_lock_bh_state(bh); | |
879 | if (jh->b_committed_data) | |
617ba13b | 880 | start = ext4_find_next_zero_bit(jh->b_committed_data, |
ac27a0ec DK |
881 | maxblocks, next); |
882 | jbd_unlock_bh_state(bh); | |
883 | } | |
884 | return -1; | |
885 | } | |
886 | ||
887 | /** | |
888 | * find_next_usable_block() | |
889 | * @start: the starting block (group relative) to find next | |
890 | * allocatable block in bitmap. | |
891 | * @bh: bufferhead contains the block group bitmap | |
892 | * @maxblocks: the ending block (group relative) for the search | |
893 | * | |
894 | * Find an allocatable block in a bitmap. We honor both the bitmap and | |
895 | * its last-committed copy (if that exists), and perform the "most | |
896 | * appropriate allocation" algorithm of looking for a free block near | |
897 | * the initial goal; then for a free byte somewhere in the bitmap; then | |
898 | * for any free bit in the bitmap. | |
899 | */ | |
617ba13b MC |
900 | static ext4_grpblk_t |
901 | find_next_usable_block(ext4_grpblk_t start, struct buffer_head *bh, | |
902 | ext4_grpblk_t maxblocks) | |
ac27a0ec | 903 | { |
617ba13b | 904 | ext4_grpblk_t here, next; |
ac27a0ec DK |
905 | char *p, *r; |
906 | ||
907 | if (start > 0) { | |
908 | /* | |
909 | * The goal was occupied; search forward for a free | |
910 | * block within the next XX blocks. | |
911 | * | |
912 | * end_goal is more or less random, but it has to be | |
617ba13b | 913 | * less than EXT4_BLOCKS_PER_GROUP. Aligning up to the |
ac27a0ec DK |
914 | * next 64-bit boundary is simple.. |
915 | */ | |
617ba13b | 916 | ext4_grpblk_t end_goal = (start + 63) & ~63; |
ac27a0ec DK |
917 | if (end_goal > maxblocks) |
918 | end_goal = maxblocks; | |
617ba13b MC |
919 | here = ext4_find_next_zero_bit(bh->b_data, end_goal, start); |
920 | if (here < end_goal && ext4_test_allocatable(here, bh)) | |
ac27a0ec | 921 | return here; |
617ba13b | 922 | ext4_debug("Bit not found near goal\n"); |
ac27a0ec DK |
923 | } |
924 | ||
925 | here = start; | |
926 | if (here < 0) | |
927 | here = 0; | |
928 | ||
929 | p = ((char *)bh->b_data) + (here >> 3); | |
ec0837f2 | 930 | r = memscan(p, 0, ((maxblocks + 7) >> 3) - (here >> 3)); |
ac27a0ec DK |
931 | next = (r - ((char *)bh->b_data)) << 3; |
932 | ||
617ba13b | 933 | if (next < maxblocks && next >= start && ext4_test_allocatable(next, bh)) |
ac27a0ec DK |
934 | return next; |
935 | ||
936 | /* | |
937 | * The bitmap search --- search forward alternately through the actual | |
938 | * bitmap and the last-committed copy until we find a bit free in | |
939 | * both | |
940 | */ | |
941 | here = bitmap_search_next_usable_block(here, bh, maxblocks); | |
942 | return here; | |
943 | } | |
944 | ||
945 | /** | |
946 | * claim_block() | |
947 | * @block: the free block (group relative) to allocate | |
948 | * @bh: the bufferhead containts the block group bitmap | |
949 | * | |
950 | * We think we can allocate this block in this bitmap. Try to set the bit. | |
951 | * If that succeeds then check that nobody has allocated and then freed the | |
952 | * block since we saw that is was not marked in b_committed_data. If it _was_ | |
953 | * allocated and freed then clear the bit in the bitmap again and return | |
954 | * zero (failure). | |
955 | */ | |
956 | static inline int | |
617ba13b | 957 | claim_block(spinlock_t *lock, ext4_grpblk_t block, struct buffer_head *bh) |
ac27a0ec DK |
958 | { |
959 | struct journal_head *jh = bh2jh(bh); | |
960 | int ret; | |
961 | ||
617ba13b | 962 | if (ext4_set_bit_atomic(lock, block, bh->b_data)) |
ac27a0ec DK |
963 | return 0; |
964 | jbd_lock_bh_state(bh); | |
617ba13b MC |
965 | if (jh->b_committed_data && ext4_test_bit(block,jh->b_committed_data)) { |
966 | ext4_clear_bit_atomic(lock, block, bh->b_data); | |
ac27a0ec DK |
967 | ret = 0; |
968 | } else { | |
969 | ret = 1; | |
970 | } | |
971 | jbd_unlock_bh_state(bh); | |
972 | return ret; | |
973 | } | |
974 | ||
975 | /** | |
617ba13b | 976 | * ext4_try_to_allocate() |
ac27a0ec DK |
977 | * @sb: superblock |
978 | * @handle: handle to this transaction | |
979 | * @group: given allocation block group | |
980 | * @bitmap_bh: bufferhead holds the block bitmap | |
981 | * @grp_goal: given target block within the group | |
982 | * @count: target number of blocks to allocate | |
983 | * @my_rsv: reservation window | |
984 | * | |
985 | * Attempt to allocate blocks within a give range. Set the range of allocation | |
986 | * first, then find the first free bit(s) from the bitmap (within the range), | |
987 | * and at last, allocate the blocks by claiming the found free bit as allocated. | |
988 | * | |
989 | * To set the range of this allocation: | |
990 | * if there is a reservation window, only try to allocate block(s) from the | |
991 | * file's own reservation window; | |
992 | * Otherwise, the allocation range starts from the give goal block, ends at | |
993 | * the block group's last block. | |
994 | * | |
995 | * If we failed to allocate the desired block then we may end up crossing to a | |
996 | * new bitmap. In that case we must release write access to the old one via | |
617ba13b | 997 | * ext4_journal_release_buffer(), else we'll run out of credits. |
ac27a0ec | 998 | */ |
617ba13b | 999 | static ext4_grpblk_t |
fd2d4291 AM |
1000 | ext4_try_to_allocate(struct super_block *sb, handle_t *handle, |
1001 | ext4_group_t group, struct buffer_head *bitmap_bh, | |
1002 | ext4_grpblk_t grp_goal, unsigned long *count, | |
1003 | struct ext4_reserve_window *my_rsv) | |
ac27a0ec | 1004 | { |
617ba13b MC |
1005 | ext4_fsblk_t group_first_block; |
1006 | ext4_grpblk_t start, end; | |
ac27a0ec DK |
1007 | unsigned long num = 0; |
1008 | ||
1009 | /* we do allocation within the reservation window if we have a window */ | |
1010 | if (my_rsv) { | |
617ba13b | 1011 | group_first_block = ext4_group_first_block_no(sb, group); |
ac27a0ec DK |
1012 | if (my_rsv->_rsv_start >= group_first_block) |
1013 | start = my_rsv->_rsv_start - group_first_block; | |
1014 | else | |
1015 | /* reservation window cross group boundary */ | |
1016 | start = 0; | |
1017 | end = my_rsv->_rsv_end - group_first_block + 1; | |
617ba13b | 1018 | if (end > EXT4_BLOCKS_PER_GROUP(sb)) |
ac27a0ec | 1019 | /* reservation window crosses group boundary */ |
617ba13b | 1020 | end = EXT4_BLOCKS_PER_GROUP(sb); |
ac27a0ec DK |
1021 | if ((start <= grp_goal) && (grp_goal < end)) |
1022 | start = grp_goal; | |
1023 | else | |
1024 | grp_goal = -1; | |
1025 | } else { | |
1026 | if (grp_goal > 0) | |
1027 | start = grp_goal; | |
1028 | else | |
1029 | start = 0; | |
617ba13b | 1030 | end = EXT4_BLOCKS_PER_GROUP(sb); |
ac27a0ec DK |
1031 | } |
1032 | ||
617ba13b | 1033 | BUG_ON(start > EXT4_BLOCKS_PER_GROUP(sb)); |
ac27a0ec DK |
1034 | |
1035 | repeat: | |
617ba13b | 1036 | if (grp_goal < 0 || !ext4_test_allocatable(grp_goal, bitmap_bh)) { |
ac27a0ec DK |
1037 | grp_goal = find_next_usable_block(start, bitmap_bh, end); |
1038 | if (grp_goal < 0) | |
1039 | goto fail_access; | |
1040 | if (!my_rsv) { | |
1041 | int i; | |
1042 | ||
1043 | for (i = 0; i < 7 && grp_goal > start && | |
617ba13b | 1044 | ext4_test_allocatable(grp_goal - 1, |
ac27a0ec DK |
1045 | bitmap_bh); |
1046 | i++, grp_goal--) | |
1047 | ; | |
1048 | } | |
1049 | } | |
1050 | start = grp_goal; | |
1051 | ||
617ba13b | 1052 | if (!claim_block(sb_bgl_lock(EXT4_SB(sb), group), |
ac27a0ec DK |
1053 | grp_goal, bitmap_bh)) { |
1054 | /* | |
1055 | * The block was allocated by another thread, or it was | |
1056 | * allocated and then freed by another thread | |
1057 | */ | |
1058 | start++; | |
1059 | grp_goal++; | |
1060 | if (start >= end) | |
1061 | goto fail_access; | |
1062 | goto repeat; | |
1063 | } | |
1064 | num++; | |
1065 | grp_goal++; | |
1066 | while (num < *count && grp_goal < end | |
617ba13b MC |
1067 | && ext4_test_allocatable(grp_goal, bitmap_bh) |
1068 | && claim_block(sb_bgl_lock(EXT4_SB(sb), group), | |
ac27a0ec DK |
1069 | grp_goal, bitmap_bh)) { |
1070 | num++; | |
1071 | grp_goal++; | |
1072 | } | |
1073 | *count = num; | |
1074 | return grp_goal - num; | |
1075 | fail_access: | |
1076 | *count = num; | |
1077 | return -1; | |
1078 | } | |
1079 | ||
1080 | /** | |
1081 | * find_next_reservable_window(): | |
1082 | * find a reservable space within the given range. | |
1083 | * It does not allocate the reservation window for now: | |
1084 | * alloc_new_reservation() will do the work later. | |
1085 | * | |
1086 | * @search_head: the head of the searching list; | |
1087 | * This is not necessarily the list head of the whole filesystem | |
1088 | * | |
1089 | * We have both head and start_block to assist the search | |
1090 | * for the reservable space. The list starts from head, | |
1091 | * but we will shift to the place where start_block is, | |
1092 | * then start from there, when looking for a reservable space. | |
1093 | * | |
1094 | * @size: the target new reservation window size | |
1095 | * | |
1096 | * @group_first_block: the first block we consider to start | |
1097 | * the real search from | |
1098 | * | |
1099 | * @last_block: | |
1100 | * the maximum block number that our goal reservable space | |
1101 | * could start from. This is normally the last block in this | |
1102 | * group. The search will end when we found the start of next | |
1103 | * possible reservable space is out of this boundary. | |
1104 | * This could handle the cross boundary reservation window | |
1105 | * request. | |
1106 | * | |
1107 | * basically we search from the given range, rather than the whole | |
1108 | * reservation double linked list, (start_block, last_block) | |
1109 | * to find a free region that is of my size and has not | |
1110 | * been reserved. | |
1111 | * | |
1112 | */ | |
1113 | static int find_next_reservable_window( | |
617ba13b MC |
1114 | struct ext4_reserve_window_node *search_head, |
1115 | struct ext4_reserve_window_node *my_rsv, | |
ac27a0ec | 1116 | struct super_block * sb, |
617ba13b MC |
1117 | ext4_fsblk_t start_block, |
1118 | ext4_fsblk_t last_block) | |
ac27a0ec DK |
1119 | { |
1120 | struct rb_node *next; | |
617ba13b MC |
1121 | struct ext4_reserve_window_node *rsv, *prev; |
1122 | ext4_fsblk_t cur; | |
ac27a0ec DK |
1123 | int size = my_rsv->rsv_goal_size; |
1124 | ||
1125 | /* TODO: make the start of the reservation window byte-aligned */ | |
1126 | /* cur = *start_block & ~7;*/ | |
1127 | cur = start_block; | |
1128 | rsv = search_head; | |
1129 | if (!rsv) | |
1130 | return -1; | |
1131 | ||
1132 | while (1) { | |
1133 | if (cur <= rsv->rsv_end) | |
1134 | cur = rsv->rsv_end + 1; | |
1135 | ||
1136 | /* TODO? | |
1137 | * in the case we could not find a reservable space | |
1138 | * that is what is expected, during the re-search, we could | |
1139 | * remember what's the largest reservable space we could have | |
1140 | * and return that one. | |
1141 | * | |
1142 | * For now it will fail if we could not find the reservable | |
1143 | * space with expected-size (or more)... | |
1144 | */ | |
1145 | if (cur > last_block) | |
1146 | return -1; /* fail */ | |
1147 | ||
1148 | prev = rsv; | |
1149 | next = rb_next(&rsv->rsv_node); | |
b78a657f | 1150 | rsv = rb_entry(next,struct ext4_reserve_window_node,rsv_node); |
ac27a0ec DK |
1151 | |
1152 | /* | |
1153 | * Reached the last reservation, we can just append to the | |
1154 | * previous one. | |
1155 | */ | |
1156 | if (!next) | |
1157 | break; | |
1158 | ||
1159 | if (cur + size <= rsv->rsv_start) { | |
1160 | /* | |
1161 | * Found a reserveable space big enough. We could | |
1162 | * have a reservation across the group boundary here | |
1163 | */ | |
1164 | break; | |
1165 | } | |
1166 | } | |
1167 | /* | |
1168 | * we come here either : | |
1169 | * when we reach the end of the whole list, | |
1170 | * and there is empty reservable space after last entry in the list. | |
1171 | * append it to the end of the list. | |
1172 | * | |
1173 | * or we found one reservable space in the middle of the list, | |
1174 | * return the reservation window that we could append to. | |
1175 | * succeed. | |
1176 | */ | |
1177 | ||
1178 | if ((prev != my_rsv) && (!rsv_is_empty(&my_rsv->rsv_window))) | |
1179 | rsv_window_remove(sb, my_rsv); | |
1180 | ||
1181 | /* | |
1182 | * Let's book the whole avaliable window for now. We will check the | |
1183 | * disk bitmap later and then, if there are free blocks then we adjust | |
1184 | * the window size if it's larger than requested. | |
1185 | * Otherwise, we will remove this node from the tree next time | |
1186 | * call find_next_reservable_window. | |
1187 | */ | |
1188 | my_rsv->rsv_start = cur; | |
1189 | my_rsv->rsv_end = cur + size - 1; | |
1190 | my_rsv->rsv_alloc_hit = 0; | |
1191 | ||
1192 | if (prev != my_rsv) | |
617ba13b | 1193 | ext4_rsv_window_add(sb, my_rsv); |
ac27a0ec DK |
1194 | |
1195 | return 0; | |
1196 | } | |
1197 | ||
1198 | /** | |
1199 | * alloc_new_reservation()--allocate a new reservation window | |
1200 | * | |
1201 | * To make a new reservation, we search part of the filesystem | |
1202 | * reservation list (the list that inside the group). We try to | |
1203 | * allocate a new reservation window near the allocation goal, | |
1204 | * or the beginning of the group, if there is no goal. | |
1205 | * | |
1206 | * We first find a reservable space after the goal, then from | |
1207 | * there, we check the bitmap for the first free block after | |
1208 | * it. If there is no free block until the end of group, then the | |
1209 | * whole group is full, we failed. Otherwise, check if the free | |
1210 | * block is inside the expected reservable space, if so, we | |
1211 | * succeed. | |
1212 | * If the first free block is outside the reservable space, then | |
1213 | * start from the first free block, we search for next available | |
1214 | * space, and go on. | |
1215 | * | |
1216 | * on succeed, a new reservation will be found and inserted into the list | |
1217 | * It contains at least one free block, and it does not overlap with other | |
1218 | * reservation windows. | |
1219 | * | |
1220 | * failed: we failed to find a reservation window in this group | |
1221 | * | |
1222 | * @rsv: the reservation | |
1223 | * | |
1224 | * @grp_goal: The goal (group-relative). It is where the search for a | |
1225 | * free reservable space should start from. | |
1226 | * if we have a grp_goal(grp_goal >0 ), then start from there, | |
1227 | * no grp_goal(grp_goal = -1), we start from the first block | |
1228 | * of the group. | |
1229 | * | |
1230 | * @sb: the super block | |
1231 | * @group: the group we are trying to allocate in | |
1232 | * @bitmap_bh: the block group block bitmap | |
1233 | * | |
1234 | */ | |
617ba13b MC |
1235 | static int alloc_new_reservation(struct ext4_reserve_window_node *my_rsv, |
1236 | ext4_grpblk_t grp_goal, struct super_block *sb, | |
fd2d4291 | 1237 | ext4_group_t group, struct buffer_head *bitmap_bh) |
ac27a0ec | 1238 | { |
617ba13b MC |
1239 | struct ext4_reserve_window_node *search_head; |
1240 | ext4_fsblk_t group_first_block, group_end_block, start_block; | |
1241 | ext4_grpblk_t first_free_block; | |
1242 | struct rb_root *fs_rsv_root = &EXT4_SB(sb)->s_rsv_window_root; | |
ac27a0ec DK |
1243 | unsigned long size; |
1244 | int ret; | |
617ba13b | 1245 | spinlock_t *rsv_lock = &EXT4_SB(sb)->s_rsv_window_lock; |
ac27a0ec | 1246 | |
617ba13b MC |
1247 | group_first_block = ext4_group_first_block_no(sb, group); |
1248 | group_end_block = group_first_block + (EXT4_BLOCKS_PER_GROUP(sb) - 1); | |
ac27a0ec DK |
1249 | |
1250 | if (grp_goal < 0) | |
1251 | start_block = group_first_block; | |
1252 | else | |
1253 | start_block = grp_goal + group_first_block; | |
1254 | ||
1255 | size = my_rsv->rsv_goal_size; | |
1256 | ||
1257 | if (!rsv_is_empty(&my_rsv->rsv_window)) { | |
1258 | /* | |
1259 | * if the old reservation is cross group boundary | |
1260 | * and if the goal is inside the old reservation window, | |
1261 | * we will come here when we just failed to allocate from | |
1262 | * the first part of the window. We still have another part | |
1263 | * that belongs to the next group. In this case, there is no | |
1264 | * point to discard our window and try to allocate a new one | |
1265 | * in this group(which will fail). we should | |
1266 | * keep the reservation window, just simply move on. | |
1267 | * | |
1268 | * Maybe we could shift the start block of the reservation | |
1269 | * window to the first block of next group. | |
1270 | */ | |
1271 | ||
1272 | if ((my_rsv->rsv_start <= group_end_block) && | |
1273 | (my_rsv->rsv_end > group_end_block) && | |
1274 | (start_block >= my_rsv->rsv_start)) | |
1275 | return -1; | |
1276 | ||
1277 | if ((my_rsv->rsv_alloc_hit > | |
1278 | (my_rsv->rsv_end - my_rsv->rsv_start + 1) / 2)) { | |
1279 | /* | |
1280 | * if the previously allocation hit ratio is | |
1281 | * greater than 1/2, then we double the size of | |
1282 | * the reservation window the next time, | |
1283 | * otherwise we keep the same size window | |
1284 | */ | |
1285 | size = size * 2; | |
617ba13b MC |
1286 | if (size > EXT4_MAX_RESERVE_BLOCKS) |
1287 | size = EXT4_MAX_RESERVE_BLOCKS; | |
ac27a0ec DK |
1288 | my_rsv->rsv_goal_size= size; |
1289 | } | |
1290 | } | |
1291 | ||
1292 | spin_lock(rsv_lock); | |
1293 | /* | |
1294 | * shift the search start to the window near the goal block | |
1295 | */ | |
1296 | search_head = search_reserve_window(fs_rsv_root, start_block); | |
1297 | ||
1298 | /* | |
1299 | * find_next_reservable_window() simply finds a reservable window | |
1300 | * inside the given range(start_block, group_end_block). | |
1301 | * | |
1302 | * To make sure the reservation window has a free bit inside it, we | |
1303 | * need to check the bitmap after we found a reservable window. | |
1304 | */ | |
1305 | retry: | |
1306 | ret = find_next_reservable_window(search_head, my_rsv, sb, | |
1307 | start_block, group_end_block); | |
1308 | ||
1309 | if (ret == -1) { | |
1310 | if (!rsv_is_empty(&my_rsv->rsv_window)) | |
1311 | rsv_window_remove(sb, my_rsv); | |
1312 | spin_unlock(rsv_lock); | |
1313 | return -1; | |
1314 | } | |
1315 | ||
1316 | /* | |
1317 | * On success, find_next_reservable_window() returns the | |
1318 | * reservation window where there is a reservable space after it. | |
1319 | * Before we reserve this reservable space, we need | |
1320 | * to make sure there is at least a free block inside this region. | |
1321 | * | |
1322 | * searching the first free bit on the block bitmap and copy of | |
1323 | * last committed bitmap alternatively, until we found a allocatable | |
1324 | * block. Search start from the start block of the reservable space | |
1325 | * we just found. | |
1326 | */ | |
1327 | spin_unlock(rsv_lock); | |
1328 | first_free_block = bitmap_search_next_usable_block( | |
1329 | my_rsv->rsv_start - group_first_block, | |
1330 | bitmap_bh, group_end_block - group_first_block + 1); | |
1331 | ||
1332 | if (first_free_block < 0) { | |
1333 | /* | |
1334 | * no free block left on the bitmap, no point | |
1335 | * to reserve the space. return failed. | |
1336 | */ | |
1337 | spin_lock(rsv_lock); | |
1338 | if (!rsv_is_empty(&my_rsv->rsv_window)) | |
1339 | rsv_window_remove(sb, my_rsv); | |
1340 | spin_unlock(rsv_lock); | |
1341 | return -1; /* failed */ | |
1342 | } | |
1343 | ||
1344 | start_block = first_free_block + group_first_block; | |
1345 | /* | |
1346 | * check if the first free block is within the | |
1347 | * free space we just reserved | |
1348 | */ | |
b2f2c76d | 1349 | if (start_block >= my_rsv->rsv_start && start_block <= my_rsv->rsv_end) |
ac27a0ec DK |
1350 | return 0; /* success */ |
1351 | /* | |
1352 | * if the first free bit we found is out of the reservable space | |
1353 | * continue search for next reservable space, | |
1354 | * start from where the free block is, | |
1355 | * we also shift the list head to where we stopped last time | |
1356 | */ | |
1357 | search_head = my_rsv; | |
1358 | spin_lock(rsv_lock); | |
1359 | goto retry; | |
1360 | } | |
1361 | ||
1362 | /** | |
1363 | * try_to_extend_reservation() | |
1364 | * @my_rsv: given reservation window | |
1365 | * @sb: super block | |
1366 | * @size: the delta to extend | |
1367 | * | |
1368 | * Attempt to expand the reservation window large enough to have | |
1369 | * required number of free blocks | |
1370 | * | |
617ba13b | 1371 | * Since ext4_try_to_allocate() will always allocate blocks within |
ac27a0ec DK |
1372 | * the reservation window range, if the window size is too small, |
1373 | * multiple blocks allocation has to stop at the end of the reservation | |
1374 | * window. To make this more efficient, given the total number of | |
1375 | * blocks needed and the current size of the window, we try to | |
1376 | * expand the reservation window size if necessary on a best-effort | |
617ba13b | 1377 | * basis before ext4_new_blocks() tries to allocate blocks, |
ac27a0ec | 1378 | */ |
617ba13b | 1379 | static void try_to_extend_reservation(struct ext4_reserve_window_node *my_rsv, |
ac27a0ec DK |
1380 | struct super_block *sb, int size) |
1381 | { | |
617ba13b | 1382 | struct ext4_reserve_window_node *next_rsv; |
ac27a0ec | 1383 | struct rb_node *next; |
617ba13b | 1384 | spinlock_t *rsv_lock = &EXT4_SB(sb)->s_rsv_window_lock; |
ac27a0ec DK |
1385 | |
1386 | if (!spin_trylock(rsv_lock)) | |
1387 | return; | |
1388 | ||
1389 | next = rb_next(&my_rsv->rsv_node); | |
1390 | ||
1391 | if (!next) | |
1392 | my_rsv->rsv_end += size; | |
1393 | else { | |
b78a657f | 1394 | next_rsv = rb_entry(next, struct ext4_reserve_window_node, rsv_node); |
ac27a0ec DK |
1395 | |
1396 | if ((next_rsv->rsv_start - my_rsv->rsv_end - 1) >= size) | |
1397 | my_rsv->rsv_end += size; | |
1398 | else | |
1399 | my_rsv->rsv_end = next_rsv->rsv_start - 1; | |
1400 | } | |
1401 | spin_unlock(rsv_lock); | |
1402 | } | |
1403 | ||
1404 | /** | |
617ba13b | 1405 | * ext4_try_to_allocate_with_rsv() |
ac27a0ec DK |
1406 | * @sb: superblock |
1407 | * @handle: handle to this transaction | |
1408 | * @group: given allocation block group | |
1409 | * @bitmap_bh: bufferhead holds the block bitmap | |
1410 | * @grp_goal: given target block within the group | |
1411 | * @count: target number of blocks to allocate | |
1412 | * @my_rsv: reservation window | |
1413 | * @errp: pointer to store the error code | |
1414 | * | |
1415 | * This is the main function used to allocate a new block and its reservation | |
1416 | * window. | |
1417 | * | |
1418 | * Each time when a new block allocation is need, first try to allocate from | |
1419 | * its own reservation. If it does not have a reservation window, instead of | |
1420 | * looking for a free bit on bitmap first, then look up the reservation list to | |
1421 | * see if it is inside somebody else's reservation window, we try to allocate a | |
1422 | * reservation window for it starting from the goal first. Then do the block | |
1423 | * allocation within the reservation window. | |
1424 | * | |
1425 | * This will avoid keeping on searching the reservation list again and | |
1426 | * again when somebody is looking for a free block (without | |
1427 | * reservation), and there are lots of free blocks, but they are all | |
1428 | * being reserved. | |
1429 | * | |
1430 | * We use a red-black tree for the per-filesystem reservation list. | |
1431 | * | |
1432 | */ | |
617ba13b MC |
1433 | static ext4_grpblk_t |
1434 | ext4_try_to_allocate_with_rsv(struct super_block *sb, handle_t *handle, | |
fd2d4291 | 1435 | ext4_group_t group, struct buffer_head *bitmap_bh, |
617ba13b MC |
1436 | ext4_grpblk_t grp_goal, |
1437 | struct ext4_reserve_window_node * my_rsv, | |
ac27a0ec DK |
1438 | unsigned long *count, int *errp) |
1439 | { | |
617ba13b MC |
1440 | ext4_fsblk_t group_first_block, group_last_block; |
1441 | ext4_grpblk_t ret = 0; | |
ac27a0ec DK |
1442 | int fatal; |
1443 | unsigned long num = *count; | |
1444 | ||
1445 | *errp = 0; | |
1446 | ||
1447 | /* | |
1448 | * Make sure we use undo access for the bitmap, because it is critical | |
1449 | * that we do the frozen_data COW on bitmap buffers in all cases even | |
1450 | * if the buffer is in BJ_Forget state in the committing transaction. | |
1451 | */ | |
1452 | BUFFER_TRACE(bitmap_bh, "get undo access for new block"); | |
617ba13b | 1453 | fatal = ext4_journal_get_undo_access(handle, bitmap_bh); |
ac27a0ec DK |
1454 | if (fatal) { |
1455 | *errp = fatal; | |
1456 | return -1; | |
1457 | } | |
1458 | ||
1459 | /* | |
1460 | * we don't deal with reservation when | |
1461 | * filesystem is mounted without reservation | |
1462 | * or the file is not a regular file | |
1463 | * or last attempt to allocate a block with reservation turned on failed | |
1464 | */ | |
1465 | if (my_rsv == NULL ) { | |
617ba13b | 1466 | ret = ext4_try_to_allocate(sb, handle, group, bitmap_bh, |
ac27a0ec DK |
1467 | grp_goal, count, NULL); |
1468 | goto out; | |
1469 | } | |
1470 | /* | |
1471 | * grp_goal is a group relative block number (if there is a goal) | |
e7dc95db | 1472 | * 0 <= grp_goal < EXT4_BLOCKS_PER_GROUP(sb) |
ac27a0ec DK |
1473 | * first block is a filesystem wide block number |
1474 | * first block is the block number of the first block in this group | |
1475 | */ | |
617ba13b MC |
1476 | group_first_block = ext4_group_first_block_no(sb, group); |
1477 | group_last_block = group_first_block + (EXT4_BLOCKS_PER_GROUP(sb) - 1); | |
ac27a0ec DK |
1478 | |
1479 | /* | |
1480 | * Basically we will allocate a new block from inode's reservation | |
1481 | * window. | |
1482 | * | |
1483 | * We need to allocate a new reservation window, if: | |
1484 | * a) inode does not have a reservation window; or | |
1485 | * b) last attempt to allocate a block from existing reservation | |
1486 | * failed; or | |
1487 | * c) we come here with a goal and with a reservation window | |
1488 | * | |
1489 | * We do not need to allocate a new reservation window if we come here | |
1490 | * at the beginning with a goal and the goal is inside the window, or | |
1491 | * we don't have a goal but already have a reservation window. | |
1492 | * then we could go to allocate from the reservation window directly. | |
1493 | */ | |
1494 | while (1) { | |
1495 | if (rsv_is_empty(&my_rsv->rsv_window) || (ret < 0) || | |
1496 | !goal_in_my_reservation(&my_rsv->rsv_window, | |
1497 | grp_goal, group, sb)) { | |
1498 | if (my_rsv->rsv_goal_size < *count) | |
1499 | my_rsv->rsv_goal_size = *count; | |
1500 | ret = alloc_new_reservation(my_rsv, grp_goal, sb, | |
1501 | group, bitmap_bh); | |
1502 | if (ret < 0) | |
1503 | break; /* failed */ | |
1504 | ||
1505 | if (!goal_in_my_reservation(&my_rsv->rsv_window, | |
1506 | grp_goal, group, sb)) | |
1507 | grp_goal = -1; | |
e7dc95db | 1508 | } else if (grp_goal >= 0) { |
1df1e63b MC |
1509 | int curr = my_rsv->rsv_end - |
1510 | (grp_goal + group_first_block) + 1; | |
1511 | ||
1512 | if (curr < *count) | |
1513 | try_to_extend_reservation(my_rsv, sb, | |
1514 | *count - curr); | |
1515 | } | |
ac27a0ec DK |
1516 | |
1517 | if ((my_rsv->rsv_start > group_last_block) || | |
1518 | (my_rsv->rsv_end < group_first_block)) { | |
617ba13b | 1519 | rsv_window_dump(&EXT4_SB(sb)->s_rsv_window_root, 1); |
ac27a0ec DK |
1520 | BUG(); |
1521 | } | |
617ba13b | 1522 | ret = ext4_try_to_allocate(sb, handle, group, bitmap_bh, |
ac27a0ec DK |
1523 | grp_goal, &num, &my_rsv->rsv_window); |
1524 | if (ret >= 0) { | |
1525 | my_rsv->rsv_alloc_hit += num; | |
1526 | *count = num; | |
1527 | break; /* succeed */ | |
1528 | } | |
1529 | num = *count; | |
1530 | } | |
1531 | out: | |
1532 | if (ret >= 0) { | |
1533 | BUFFER_TRACE(bitmap_bh, "journal_dirty_metadata for " | |
1534 | "bitmap block"); | |
617ba13b | 1535 | fatal = ext4_journal_dirty_metadata(handle, bitmap_bh); |
ac27a0ec DK |
1536 | if (fatal) { |
1537 | *errp = fatal; | |
1538 | return -1; | |
1539 | } | |
1540 | return ret; | |
1541 | } | |
1542 | ||
1543 | BUFFER_TRACE(bitmap_bh, "journal_release_buffer"); | |
617ba13b | 1544 | ext4_journal_release_buffer(handle, bitmap_bh); |
ac27a0ec DK |
1545 | return ret; |
1546 | } | |
1547 | ||
1548 | /** | |
617ba13b | 1549 | * ext4_has_free_blocks() |
ac27a0ec DK |
1550 | * @sbi: in-core super block structure. |
1551 | * | |
1552 | * Check if filesystem has at least 1 free block available for allocation. | |
1553 | */ | |
617ba13b | 1554 | static int ext4_has_free_blocks(struct ext4_sb_info *sbi) |
ac27a0ec | 1555 | { |
617ba13b | 1556 | ext4_fsblk_t free_blocks, root_blocks; |
ac27a0ec DK |
1557 | |
1558 | free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter); | |
bd81d8ee | 1559 | root_blocks = ext4_r_blocks_count(sbi->s_es); |
ac27a0ec DK |
1560 | if (free_blocks < root_blocks + 1 && !capable(CAP_SYS_RESOURCE) && |
1561 | sbi->s_resuid != current->fsuid && | |
1562 | (sbi->s_resgid == 0 || !in_group_p (sbi->s_resgid))) { | |
1563 | return 0; | |
1564 | } | |
1565 | return 1; | |
1566 | } | |
1567 | ||
1568 | /** | |
617ba13b | 1569 | * ext4_should_retry_alloc() |
ac27a0ec DK |
1570 | * @sb: super block |
1571 | * @retries number of attemps has been made | |
1572 | * | |
617ba13b | 1573 | * ext4_should_retry_alloc() is called when ENOSPC is returned, and if |
ac27a0ec DK |
1574 | * it is profitable to retry the operation, this function will wait |
1575 | * for the current or commiting transaction to complete, and then | |
1576 | * return TRUE. | |
1577 | * | |
1578 | * if the total number of retries exceed three times, return FALSE. | |
1579 | */ | |
617ba13b | 1580 | int ext4_should_retry_alloc(struct super_block *sb, int *retries) |
ac27a0ec | 1581 | { |
617ba13b | 1582 | if (!ext4_has_free_blocks(EXT4_SB(sb)) || (*retries)++ > 3) |
ac27a0ec DK |
1583 | return 0; |
1584 | ||
1585 | jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id); | |
1586 | ||
dab291af | 1587 | return jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal); |
ac27a0ec DK |
1588 | } |
1589 | ||
1590 | /** | |
c9de560d | 1591 | * ext4_new_blocks_old() -- core block(s) allocation function |
ac27a0ec DK |
1592 | * @handle: handle to this transaction |
1593 | * @inode: file inode | |
1594 | * @goal: given target block(filesystem wide) | |
1595 | * @count: target number of blocks to allocate | |
1596 | * @errp: error code | |
1597 | * | |
617ba13b | 1598 | * ext4_new_blocks uses a goal block to assist allocation. It tries to |
ac27a0ec DK |
1599 | * allocate block(s) from the block group contains the goal block first. If that |
1600 | * fails, it will try to allocate block(s) from other block groups without | |
1601 | * any specific goal block. | |
1602 | * | |
1603 | */ | |
c9de560d | 1604 | ext4_fsblk_t ext4_new_blocks_old(handle_t *handle, struct inode *inode, |
617ba13b | 1605 | ext4_fsblk_t goal, unsigned long *count, int *errp) |
ac27a0ec DK |
1606 | { |
1607 | struct buffer_head *bitmap_bh = NULL; | |
1608 | struct buffer_head *gdp_bh; | |
fd2d4291 AM |
1609 | ext4_group_t group_no; |
1610 | ext4_group_t goal_group; | |
617ba13b MC |
1611 | ext4_grpblk_t grp_target_blk; /* blockgroup relative goal block */ |
1612 | ext4_grpblk_t grp_alloc_blk; /* blockgroup-relative allocated block*/ | |
1613 | ext4_fsblk_t ret_block; /* filesyetem-wide allocated block */ | |
fd2d4291 | 1614 | ext4_group_t bgi; /* blockgroup iteration index */ |
ac27a0ec DK |
1615 | int fatal = 0, err; |
1616 | int performed_allocation = 0; | |
617ba13b | 1617 | ext4_grpblk_t free_blocks; /* number of free blocks in a group */ |
ac27a0ec | 1618 | struct super_block *sb; |
617ba13b MC |
1619 | struct ext4_group_desc *gdp; |
1620 | struct ext4_super_block *es; | |
1621 | struct ext4_sb_info *sbi; | |
1622 | struct ext4_reserve_window_node *my_rsv = NULL; | |
1623 | struct ext4_block_alloc_info *block_i; | |
ac27a0ec | 1624 | unsigned short windowsz = 0; |
fd2d4291 | 1625 | ext4_group_t ngroups; |
ac27a0ec DK |
1626 | unsigned long num = *count; |
1627 | ||
1628 | *errp = -ENOSPC; | |
1629 | sb = inode->i_sb; | |
1630 | if (!sb) { | |
617ba13b | 1631 | printk("ext4_new_block: nonexistent device"); |
ac27a0ec DK |
1632 | return 0; |
1633 | } | |
1634 | ||
1635 | /* | |
1636 | * Check quota for allocation of this block. | |
1637 | */ | |
1638 | if (DQUOT_ALLOC_BLOCK(inode, num)) { | |
1639 | *errp = -EDQUOT; | |
1640 | return 0; | |
1641 | } | |
1642 | ||
617ba13b MC |
1643 | sbi = EXT4_SB(sb); |
1644 | es = EXT4_SB(sb)->s_es; | |
c549a95d | 1645 | ext4_debug("goal=%llu.\n", goal); |
ac27a0ec DK |
1646 | /* |
1647 | * Allocate a block from reservation only when | |
1648 | * filesystem is mounted with reservation(default,-o reservation), and | |
1649 | * it's a regular file, and | |
1650 | * the desired window size is greater than 0 (One could use ioctl | |
617ba13b | 1651 | * command EXT4_IOC_SETRSVSZ to set the window size to 0 to turn off |
ac27a0ec DK |
1652 | * reservation on that particular file) |
1653 | */ | |
617ba13b | 1654 | block_i = EXT4_I(inode)->i_block_alloc_info; |
ac27a0ec DK |
1655 | if (block_i && ((windowsz = block_i->rsv_window_node.rsv_goal_size) > 0)) |
1656 | my_rsv = &block_i->rsv_window_node; | |
1657 | ||
617ba13b | 1658 | if (!ext4_has_free_blocks(sbi)) { |
ac27a0ec DK |
1659 | *errp = -ENOSPC; |
1660 | goto out; | |
1661 | } | |
1662 | ||
1663 | /* | |
1664 | * First, test whether the goal block is free. | |
1665 | */ | |
1666 | if (goal < le32_to_cpu(es->s_first_data_block) || | |
bd81d8ee | 1667 | goal >= ext4_blocks_count(es)) |
ac27a0ec | 1668 | goal = le32_to_cpu(es->s_first_data_block); |
3a5b2ecd | 1669 | ext4_get_group_no_and_offset(sb, goal, &group_no, &grp_target_blk); |
ac27a0ec DK |
1670 | goal_group = group_no; |
1671 | retry_alloc: | |
617ba13b | 1672 | gdp = ext4_get_group_desc(sb, group_no, &gdp_bh); |
ac27a0ec DK |
1673 | if (!gdp) |
1674 | goto io_error; | |
1675 | ||
1676 | free_blocks = le16_to_cpu(gdp->bg_free_blocks_count); | |
1677 | /* | |
1678 | * if there is not enough free blocks to make a new resevation | |
1679 | * turn off reservation for this allocation | |
1680 | */ | |
1681 | if (my_rsv && (free_blocks < windowsz) | |
1682 | && (rsv_is_empty(&my_rsv->rsv_window))) | |
1683 | my_rsv = NULL; | |
1684 | ||
1685 | if (free_blocks > 0) { | |
ac27a0ec DK |
1686 | bitmap_bh = read_block_bitmap(sb, group_no); |
1687 | if (!bitmap_bh) | |
1688 | goto io_error; | |
617ba13b | 1689 | grp_alloc_blk = ext4_try_to_allocate_with_rsv(sb, handle, |
ac27a0ec DK |
1690 | group_no, bitmap_bh, grp_target_blk, |
1691 | my_rsv, &num, &fatal); | |
1692 | if (fatal) | |
1693 | goto out; | |
1694 | if (grp_alloc_blk >= 0) | |
1695 | goto allocated; | |
1696 | } | |
1697 | ||
617ba13b | 1698 | ngroups = EXT4_SB(sb)->s_groups_count; |
ac27a0ec DK |
1699 | smp_rmb(); |
1700 | ||
1701 | /* | |
1702 | * Now search the rest of the groups. We assume that | |
144704e5 | 1703 | * group_no and gdp correctly point to the last group visited. |
ac27a0ec DK |
1704 | */ |
1705 | for (bgi = 0; bgi < ngroups; bgi++) { | |
1706 | group_no++; | |
1707 | if (group_no >= ngroups) | |
1708 | group_no = 0; | |
617ba13b | 1709 | gdp = ext4_get_group_desc(sb, group_no, &gdp_bh); |
341cee43 HD |
1710 | if (!gdp) |
1711 | goto io_error; | |
ac27a0ec DK |
1712 | free_blocks = le16_to_cpu(gdp->bg_free_blocks_count); |
1713 | /* | |
1714 | * skip this group if the number of | |
1715 | * free blocks is less than half of the reservation | |
1716 | * window size. | |
1717 | */ | |
1718 | if (free_blocks <= (windowsz/2)) | |
1719 | continue; | |
1720 | ||
1721 | brelse(bitmap_bh); | |
1722 | bitmap_bh = read_block_bitmap(sb, group_no); | |
1723 | if (!bitmap_bh) | |
1724 | goto io_error; | |
1725 | /* | |
1726 | * try to allocate block(s) from this group, without a goal(-1). | |
1727 | */ | |
617ba13b | 1728 | grp_alloc_blk = ext4_try_to_allocate_with_rsv(sb, handle, |
ac27a0ec DK |
1729 | group_no, bitmap_bh, -1, my_rsv, |
1730 | &num, &fatal); | |
1731 | if (fatal) | |
1732 | goto out; | |
1733 | if (grp_alloc_blk >= 0) | |
1734 | goto allocated; | |
1735 | } | |
1736 | /* | |
1737 | * We may end up a bogus ealier ENOSPC error due to | |
1738 | * filesystem is "full" of reservations, but | |
1739 | * there maybe indeed free blocks avaliable on disk | |
1740 | * In this case, we just forget about the reservations | |
1741 | * just do block allocation as without reservations. | |
1742 | */ | |
1743 | if (my_rsv) { | |
1744 | my_rsv = NULL; | |
cd16c8f7 | 1745 | windowsz = 0; |
ac27a0ec DK |
1746 | group_no = goal_group; |
1747 | goto retry_alloc; | |
1748 | } | |
1749 | /* No space left on the device */ | |
1750 | *errp = -ENOSPC; | |
1751 | goto out; | |
1752 | ||
1753 | allocated: | |
1754 | ||
c549a95d | 1755 | ext4_debug("using block group %lu(%d)\n", |
ac27a0ec DK |
1756 | group_no, gdp->bg_free_blocks_count); |
1757 | ||
1758 | BUFFER_TRACE(gdp_bh, "get_write_access"); | |
617ba13b | 1759 | fatal = ext4_journal_get_write_access(handle, gdp_bh); |
ac27a0ec DK |
1760 | if (fatal) |
1761 | goto out; | |
1762 | ||
617ba13b | 1763 | ret_block = grp_alloc_blk + ext4_group_first_block_no(sb, group_no); |
ac27a0ec | 1764 | |
8fadc143 | 1765 | if (in_range(ext4_block_bitmap(sb, gdp), ret_block, num) || |
29bc5b4f | 1766 | in_range(ext4_inode_bitmap(sb, gdp), ret_block, num) || |
8fadc143 | 1767 | in_range(ret_block, ext4_inode_table(sb, gdp), |
bd81d8ee | 1768 | EXT4_SB(sb)->s_itb_per_group) || |
8fadc143 | 1769 | in_range(ret_block + num - 1, ext4_inode_table(sb, gdp), |
cb47dce7 | 1770 | EXT4_SB(sb)->s_itb_per_group)) { |
617ba13b | 1771 | ext4_error(sb, "ext4_new_block", |
ac27a0ec | 1772 | "Allocating block in system zone - " |
2ae02107 | 1773 | "blocks from %llu, length %lu", |
ac27a0ec | 1774 | ret_block, num); |
cb47dce7 AK |
1775 | goto out; |
1776 | } | |
ac27a0ec DK |
1777 | |
1778 | performed_allocation = 1; | |
1779 | ||
e23291b9 | 1780 | #ifdef CONFIG_JBD2_DEBUG |
ac27a0ec DK |
1781 | { |
1782 | struct buffer_head *debug_bh; | |
1783 | ||
1784 | /* Record bitmap buffer state in the newly allocated block */ | |
1785 | debug_bh = sb_find_get_block(sb, ret_block); | |
1786 | if (debug_bh) { | |
1787 | BUFFER_TRACE(debug_bh, "state when allocated"); | |
1788 | BUFFER_TRACE2(debug_bh, bitmap_bh, "bitmap state"); | |
1789 | brelse(debug_bh); | |
1790 | } | |
1791 | } | |
1792 | jbd_lock_bh_state(bitmap_bh); | |
1793 | spin_lock(sb_bgl_lock(sbi, group_no)); | |
1794 | if (buffer_jbd(bitmap_bh) && bh2jh(bitmap_bh)->b_committed_data) { | |
1795 | int i; | |
1796 | ||
1797 | for (i = 0; i < num; i++) { | |
617ba13b | 1798 | if (ext4_test_bit(grp_alloc_blk+i, |
ac27a0ec DK |
1799 | bh2jh(bitmap_bh)->b_committed_data)) { |
1800 | printk("%s: block was unexpectedly set in " | |
1801 | "b_committed_data\n", __FUNCTION__); | |
1802 | } | |
1803 | } | |
1804 | } | |
617ba13b | 1805 | ext4_debug("found bit %d\n", grp_alloc_blk); |
ac27a0ec DK |
1806 | spin_unlock(sb_bgl_lock(sbi, group_no)); |
1807 | jbd_unlock_bh_state(bitmap_bh); | |
1808 | #endif | |
1809 | ||
bd81d8ee | 1810 | if (ret_block + num - 1 >= ext4_blocks_count(es)) { |
617ba13b | 1811 | ext4_error(sb, "ext4_new_block", |
2ae02107 | 1812 | "block(%llu) >= blocks count(%llu) - " |
3a5b2ecd | 1813 | "block_group = %lu, es == %p ", ret_block, |
bd81d8ee | 1814 | ext4_blocks_count(es), group_no, es); |
ac27a0ec DK |
1815 | goto out; |
1816 | } | |
1817 | ||
1818 | /* | |
1819 | * It is up to the caller to add the new buffer to a journal | |
1820 | * list of some description. We don't know in advance whether | |
1821 | * the caller wants to use it as metadata or data. | |
1822 | */ | |
ac27a0ec | 1823 | spin_lock(sb_bgl_lock(sbi, group_no)); |
717d50e4 AD |
1824 | if (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) |
1825 | gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT); | |
ac27a0ec DK |
1826 | gdp->bg_free_blocks_count = |
1827 | cpu_to_le16(le16_to_cpu(gdp->bg_free_blocks_count)-num); | |
717d50e4 | 1828 | gdp->bg_checksum = ext4_group_desc_csum(sbi, group_no, gdp); |
ac27a0ec | 1829 | spin_unlock(sb_bgl_lock(sbi, group_no)); |
3cb4f9fa | 1830 | percpu_counter_sub(&sbi->s_freeblocks_counter, num); |
ac27a0ec DK |
1831 | |
1832 | BUFFER_TRACE(gdp_bh, "journal_dirty_metadata for group descriptor"); | |
617ba13b | 1833 | err = ext4_journal_dirty_metadata(handle, gdp_bh); |
ac27a0ec DK |
1834 | if (!fatal) |
1835 | fatal = err; | |
1836 | ||
1837 | sb->s_dirt = 1; | |
1838 | if (fatal) | |
1839 | goto out; | |
1840 | ||
1841 | *errp = 0; | |
1842 | brelse(bitmap_bh); | |
1843 | DQUOT_FREE_BLOCK(inode, *count-num); | |
1844 | *count = num; | |
1845 | return ret_block; | |
1846 | ||
1847 | io_error: | |
1848 | *errp = -EIO; | |
1849 | out: | |
1850 | if (fatal) { | |
1851 | *errp = fatal; | |
617ba13b | 1852 | ext4_std_error(sb, fatal); |
ac27a0ec DK |
1853 | } |
1854 | /* | |
1855 | * Undo the block allocation | |
1856 | */ | |
1857 | if (!performed_allocation) | |
1858 | DQUOT_FREE_BLOCK(inode, *count); | |
1859 | brelse(bitmap_bh); | |
1860 | return 0; | |
1861 | } | |
1862 | ||
617ba13b | 1863 | ext4_fsblk_t ext4_new_block(handle_t *handle, struct inode *inode, |
c9de560d AT |
1864 | ext4_fsblk_t goal, int *errp) |
1865 | { | |
1866 | struct ext4_allocation_request ar; | |
1867 | ext4_fsblk_t ret; | |
1868 | ||
1869 | if (!test_opt(inode->i_sb, MBALLOC)) { | |
1870 | unsigned long count = 1; | |
1871 | ret = ext4_new_blocks_old(handle, inode, goal, &count, errp); | |
1872 | return ret; | |
1873 | } | |
1874 | ||
1875 | memset(&ar, 0, sizeof(ar)); | |
1876 | ar.inode = inode; | |
1877 | ar.goal = goal; | |
1878 | ar.len = 1; | |
1879 | ret = ext4_mb_new_blocks(handle, &ar, errp); | |
1880 | return ret; | |
1881 | } | |
1882 | ||
1883 | ext4_fsblk_t ext4_new_blocks(handle_t *handle, struct inode *inode, | |
1884 | ext4_fsblk_t goal, unsigned long *count, int *errp) | |
ac27a0ec | 1885 | { |
c9de560d AT |
1886 | struct ext4_allocation_request ar; |
1887 | ext4_fsblk_t ret; | |
ac27a0ec | 1888 | |
c9de560d AT |
1889 | if (!test_opt(inode->i_sb, MBALLOC)) { |
1890 | ret = ext4_new_blocks_old(handle, inode, goal, count, errp); | |
1891 | return ret; | |
1892 | } | |
1893 | ||
1894 | memset(&ar, 0, sizeof(ar)); | |
1895 | ar.inode = inode; | |
1896 | ar.goal = goal; | |
1897 | ar.len = *count; | |
1898 | ret = ext4_mb_new_blocks(handle, &ar, errp); | |
1899 | *count = ar.len; | |
1900 | return ret; | |
ac27a0ec DK |
1901 | } |
1902 | ||
c9de560d | 1903 | |
ac27a0ec | 1904 | /** |
617ba13b | 1905 | * ext4_count_free_blocks() -- count filesystem free blocks |
ac27a0ec DK |
1906 | * @sb: superblock |
1907 | * | |
1908 | * Adds up the number of free blocks from each block group. | |
1909 | */ | |
617ba13b | 1910 | ext4_fsblk_t ext4_count_free_blocks(struct super_block *sb) |
ac27a0ec | 1911 | { |
617ba13b MC |
1912 | ext4_fsblk_t desc_count; |
1913 | struct ext4_group_desc *gdp; | |
fd2d4291 AM |
1914 | ext4_group_t i; |
1915 | ext4_group_t ngroups = EXT4_SB(sb)->s_groups_count; | |
617ba13b MC |
1916 | #ifdef EXT4FS_DEBUG |
1917 | struct ext4_super_block *es; | |
1918 | ext4_fsblk_t bitmap_count; | |
ac27a0ec DK |
1919 | unsigned long x; |
1920 | struct buffer_head *bitmap_bh = NULL; | |
1921 | ||
617ba13b | 1922 | es = EXT4_SB(sb)->s_es; |
ac27a0ec DK |
1923 | desc_count = 0; |
1924 | bitmap_count = 0; | |
1925 | gdp = NULL; | |
1926 | ||
1927 | smp_rmb(); | |
1928 | for (i = 0; i < ngroups; i++) { | |
617ba13b | 1929 | gdp = ext4_get_group_desc(sb, i, NULL); |
ac27a0ec DK |
1930 | if (!gdp) |
1931 | continue; | |
1932 | desc_count += le16_to_cpu(gdp->bg_free_blocks_count); | |
1933 | brelse(bitmap_bh); | |
1934 | bitmap_bh = read_block_bitmap(sb, i); | |
1935 | if (bitmap_bh == NULL) | |
1936 | continue; | |
1937 | ||
617ba13b | 1938 | x = ext4_count_free(bitmap_bh, sb->s_blocksize); |
fd2d4291 | 1939 | printk(KERN_DEBUG "group %lu: stored = %d, counted = %lu\n", |
ac27a0ec DK |
1940 | i, le16_to_cpu(gdp->bg_free_blocks_count), x); |
1941 | bitmap_count += x; | |
1942 | } | |
1943 | brelse(bitmap_bh); | |
2ae02107 MC |
1944 | printk("ext4_count_free_blocks: stored = %llu" |
1945 | ", computed = %llu, %llu\n", | |
c549a95d | 1946 | ext4_free_blocks_count(es), |
ac27a0ec DK |
1947 | desc_count, bitmap_count); |
1948 | return bitmap_count; | |
1949 | #else | |
1950 | desc_count = 0; | |
1951 | smp_rmb(); | |
1952 | for (i = 0; i < ngroups; i++) { | |
617ba13b | 1953 | gdp = ext4_get_group_desc(sb, i, NULL); |
ac27a0ec DK |
1954 | if (!gdp) |
1955 | continue; | |
1956 | desc_count += le16_to_cpu(gdp->bg_free_blocks_count); | |
1957 | } | |
1958 | ||
1959 | return desc_count; | |
1960 | #endif | |
1961 | } | |
1962 | ||
fd2d4291 | 1963 | static inline int test_root(ext4_group_t a, int b) |
ac27a0ec DK |
1964 | { |
1965 | int num = b; | |
1966 | ||
1967 | while (a > num) | |
1968 | num *= b; | |
1969 | return num == a; | |
1970 | } | |
1971 | ||
fd2d4291 | 1972 | static int ext4_group_sparse(ext4_group_t group) |
ac27a0ec DK |
1973 | { |
1974 | if (group <= 1) | |
1975 | return 1; | |
1976 | if (!(group & 1)) | |
1977 | return 0; | |
1978 | return (test_root(group, 7) || test_root(group, 5) || | |
1979 | test_root(group, 3)); | |
1980 | } | |
1981 | ||
1982 | /** | |
617ba13b | 1983 | * ext4_bg_has_super - number of blocks used by the superblock in group |
ac27a0ec DK |
1984 | * @sb: superblock for filesystem |
1985 | * @group: group number to check | |
1986 | * | |
1987 | * Return the number of blocks used by the superblock (primary or backup) | |
1988 | * in this group. Currently this will be only 0 or 1. | |
1989 | */ | |
fd2d4291 | 1990 | int ext4_bg_has_super(struct super_block *sb, ext4_group_t group) |
ac27a0ec | 1991 | { |
617ba13b MC |
1992 | if (EXT4_HAS_RO_COMPAT_FEATURE(sb, |
1993 | EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER) && | |
1994 | !ext4_group_sparse(group)) | |
ac27a0ec DK |
1995 | return 0; |
1996 | return 1; | |
1997 | } | |
1998 | ||
fd2d4291 AM |
1999 | static unsigned long ext4_bg_num_gdb_meta(struct super_block *sb, |
2000 | ext4_group_t group) | |
ac27a0ec | 2001 | { |
617ba13b | 2002 | unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); |
fd2d4291 AM |
2003 | ext4_group_t first = metagroup * EXT4_DESC_PER_BLOCK(sb); |
2004 | ext4_group_t last = first + EXT4_DESC_PER_BLOCK(sb) - 1; | |
ac27a0ec DK |
2005 | |
2006 | if (group == first || group == first + 1 || group == last) | |
2007 | return 1; | |
2008 | return 0; | |
2009 | } | |
2010 | ||
fd2d4291 AM |
2011 | static unsigned long ext4_bg_num_gdb_nometa(struct super_block *sb, |
2012 | ext4_group_t group) | |
ac27a0ec | 2013 | { |
617ba13b MC |
2014 | if (EXT4_HAS_RO_COMPAT_FEATURE(sb, |
2015 | EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER) && | |
2016 | !ext4_group_sparse(group)) | |
ac27a0ec | 2017 | return 0; |
617ba13b | 2018 | return EXT4_SB(sb)->s_gdb_count; |
ac27a0ec DK |
2019 | } |
2020 | ||
2021 | /** | |
617ba13b | 2022 | * ext4_bg_num_gdb - number of blocks used by the group table in group |
ac27a0ec DK |
2023 | * @sb: superblock for filesystem |
2024 | * @group: group number to check | |
2025 | * | |
2026 | * Return the number of blocks used by the group descriptor table | |
2027 | * (primary or backup) in this group. In the future there may be a | |
2028 | * different number of descriptor blocks in each group. | |
2029 | */ | |
fd2d4291 | 2030 | unsigned long ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group) |
ac27a0ec DK |
2031 | { |
2032 | unsigned long first_meta_bg = | |
617ba13b MC |
2033 | le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg); |
2034 | unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); | |
ac27a0ec | 2035 | |
617ba13b | 2036 | if (!EXT4_HAS_INCOMPAT_FEATURE(sb,EXT4_FEATURE_INCOMPAT_META_BG) || |
ac27a0ec | 2037 | metagroup < first_meta_bg) |
617ba13b | 2038 | return ext4_bg_num_gdb_nometa(sb,group); |
ac27a0ec | 2039 | |
617ba13b | 2040 | return ext4_bg_num_gdb_meta(sb,group); |
ac27a0ec DK |
2041 | |
2042 | } |