Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/fs/ext2/balloc.c | |
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 | ||
1da177e4 LT |
14 | #include "ext2.h" |
15 | #include <linux/quotaops.h> | |
16 | #include <linux/sched.h> | |
17 | #include <linux/buffer_head.h> | |
16f7e0fe | 18 | #include <linux/capability.h> |
1da177e4 LT |
19 | |
20 | /* | |
21 | * balloc.c contains the blocks allocation and deallocation routines | |
22 | */ | |
23 | ||
24 | /* | |
25 | * The free blocks are managed by bitmaps. A file system contains several | |
26 | * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap | |
27 | * block for inodes, N blocks for the inode table and data blocks. | |
28 | * | |
29 | * The file system contains group descriptors which are located after the | |
30 | * super block. Each descriptor contains the number of the bitmap block and | |
31 | * the free blocks count in the block. The descriptors are loaded in memory | |
e627432c | 32 | * when a file system is mounted (see ext2_fill_super). |
1da177e4 LT |
33 | */ |
34 | ||
35 | ||
36 | #define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1) | |
37 | ||
38 | struct ext2_group_desc * ext2_get_group_desc(struct super_block * sb, | |
39 | unsigned int block_group, | |
40 | struct buffer_head ** bh) | |
41 | { | |
42 | unsigned long group_desc; | |
43 | unsigned long offset; | |
44 | struct ext2_group_desc * desc; | |
45 | struct ext2_sb_info *sbi = EXT2_SB(sb); | |
46 | ||
47 | if (block_group >= sbi->s_groups_count) { | |
48 | ext2_error (sb, "ext2_get_group_desc", | |
49 | "block_group >= groups_count - " | |
50 | "block_group = %d, groups_count = %lu", | |
51 | block_group, sbi->s_groups_count); | |
52 | ||
53 | return NULL; | |
54 | } | |
55 | ||
56 | group_desc = block_group >> EXT2_DESC_PER_BLOCK_BITS(sb); | |
57 | offset = block_group & (EXT2_DESC_PER_BLOCK(sb) - 1); | |
58 | if (!sbi->s_group_desc[group_desc]) { | |
59 | ext2_error (sb, "ext2_get_group_desc", | |
60 | "Group descriptor not loaded - " | |
61 | "block_group = %d, group_desc = %lu, desc = %lu", | |
62 | block_group, group_desc, offset); | |
63 | return NULL; | |
64 | } | |
65 | ||
66 | desc = (struct ext2_group_desc *) sbi->s_group_desc[group_desc]->b_data; | |
67 | if (bh) | |
68 | *bh = sbi->s_group_desc[group_desc]; | |
69 | return desc + offset; | |
70 | } | |
71 | ||
01584fa6 AK |
72 | static int ext2_valid_block_bitmap(struct super_block *sb, |
73 | struct ext2_group_desc *desc, | |
74 | unsigned int block_group, | |
75 | struct buffer_head *bh) | |
76 | { | |
77 | ext2_grpblk_t offset; | |
78 | ext2_grpblk_t next_zero_bit; | |
79 | ext2_fsblk_t bitmap_blk; | |
80 | ext2_fsblk_t group_first_block; | |
81 | ||
82 | group_first_block = ext2_group_first_block_no(sb, block_group); | |
83 | ||
84 | /* check whether block bitmap block number is set */ | |
85 | bitmap_blk = le32_to_cpu(desc->bg_block_bitmap); | |
86 | offset = bitmap_blk - group_first_block; | |
87 | if (!ext2_test_bit(offset, bh->b_data)) | |
88 | /* bad block bitmap */ | |
89 | goto err_out; | |
90 | ||
91 | /* check whether the inode bitmap block number is set */ | |
92 | bitmap_blk = le32_to_cpu(desc->bg_inode_bitmap); | |
93 | offset = bitmap_blk - group_first_block; | |
94 | if (!ext2_test_bit(offset, bh->b_data)) | |
95 | /* bad block bitmap */ | |
96 | goto err_out; | |
97 | ||
98 | /* check whether the inode table block number is set */ | |
99 | bitmap_blk = le32_to_cpu(desc->bg_inode_table); | |
100 | offset = bitmap_blk - group_first_block; | |
101 | next_zero_bit = ext2_find_next_zero_bit(bh->b_data, | |
102 | offset + EXT2_SB(sb)->s_itb_per_group, | |
103 | offset); | |
104 | if (next_zero_bit >= offset + EXT2_SB(sb)->s_itb_per_group) | |
105 | /* good bitmap for inode tables */ | |
106 | return 1; | |
107 | ||
108 | err_out: | |
109 | ext2_error(sb, __FUNCTION__, | |
110 | "Invalid block bitmap - " | |
111 | "block_group = %d, block = %lu", | |
112 | block_group, bitmap_blk); | |
113 | return 0; | |
114 | } | |
115 | ||
1da177e4 | 116 | /* |
01584fa6 AK |
117 | * Read the bitmap for a given block_group,and validate the |
118 | * bits for block/inode/inode tables are set in the bitmaps | |
1da177e4 LT |
119 | * |
120 | * Return buffer_head on success or NULL in case of failure. | |
121 | */ | |
122 | static struct buffer_head * | |
123 | read_block_bitmap(struct super_block *sb, unsigned int block_group) | |
124 | { | |
125 | struct ext2_group_desc * desc; | |
126 | struct buffer_head * bh = NULL; | |
01584fa6 AK |
127 | ext2_fsblk_t bitmap_blk; |
128 | ||
129 | desc = ext2_get_group_desc(sb, block_group, NULL); | |
1da177e4 | 130 | if (!desc) |
01584fa6 AK |
131 | return NULL; |
132 | bitmap_blk = le32_to_cpu(desc->bg_block_bitmap); | |
133 | bh = sb_getblk(sb, bitmap_blk); | |
134 | if (unlikely(!bh)) { | |
135 | ext2_error(sb, __FUNCTION__, | |
136 | "Cannot read block bitmap - " | |
137 | "block_group = %d, block_bitmap = %u", | |
138 | block_group, le32_to_cpu(desc->bg_block_bitmap)); | |
139 | return NULL; | |
140 | } | |
141 | if (likely(bh_uptodate_or_lock(bh))) | |
142 | return bh; | |
143 | ||
144 | if (bh_submit_read(bh) < 0) { | |
145 | brelse(bh); | |
146 | ext2_error(sb, __FUNCTION__, | |
1da177e4 LT |
147 | "Cannot read block bitmap - " |
148 | "block_group = %d, block_bitmap = %u", | |
149 | block_group, le32_to_cpu(desc->bg_block_bitmap)); | |
01584fa6 AK |
150 | return NULL; |
151 | } | |
152 | if (!ext2_valid_block_bitmap(sb, desc, block_group, bh)) { | |
153 | brelse(bh); | |
154 | return NULL; | |
155 | } | |
156 | ||
0b832a4b | 157 | return bh; |
1da177e4 LT |
158 | } |
159 | ||
1da177e4 LT |
160 | static void release_blocks(struct super_block *sb, int count) |
161 | { | |
162 | if (count) { | |
163 | struct ext2_sb_info *sbi = EXT2_SB(sb); | |
164 | ||
aa0dff2d | 165 | percpu_counter_add(&sbi->s_freeblocks_counter, count); |
1da177e4 LT |
166 | sb->s_dirt = 1; |
167 | } | |
168 | } | |
169 | ||
a686cd89 | 170 | static void group_adjust_blocks(struct super_block *sb, int group_no, |
1da177e4 LT |
171 | struct ext2_group_desc *desc, struct buffer_head *bh, int count) |
172 | { | |
173 | if (count) { | |
174 | struct ext2_sb_info *sbi = EXT2_SB(sb); | |
175 | unsigned free_blocks; | |
176 | ||
177 | spin_lock(sb_bgl_lock(sbi, group_no)); | |
178 | free_blocks = le16_to_cpu(desc->bg_free_blocks_count); | |
179 | desc->bg_free_blocks_count = cpu_to_le16(free_blocks + count); | |
180 | spin_unlock(sb_bgl_lock(sbi, group_no)); | |
181 | sb->s_dirt = 1; | |
182 | mark_buffer_dirty(bh); | |
183 | } | |
184 | } | |
185 | ||
a686cd89 MB |
186 | /* |
187 | * The reservation window structure operations | |
188 | * -------------------------------------------- | |
189 | * Operations include: | |
190 | * dump, find, add, remove, is_empty, find_next_reservable_window, etc. | |
191 | * | |
192 | * We use a red-black tree to represent per-filesystem reservation | |
193 | * windows. | |
194 | * | |
195 | */ | |
196 | ||
197 | /** | |
198 | * __rsv_window_dump() -- Dump the filesystem block allocation reservation map | |
199 | * @rb_root: root of per-filesystem reservation rb tree | |
200 | * @verbose: verbose mode | |
201 | * @fn: function which wishes to dump the reservation map | |
202 | * | |
203 | * If verbose is turned on, it will print the whole block reservation | |
204 | * windows(start, end). Otherwise, it will only print out the "bad" windows, | |
205 | * those windows that overlap with their immediate neighbors. | |
206 | */ | |
207 | #if 1 | |
208 | static void __rsv_window_dump(struct rb_root *root, int verbose, | |
209 | const char *fn) | |
210 | { | |
211 | struct rb_node *n; | |
212 | struct ext2_reserve_window_node *rsv, *prev; | |
213 | int bad; | |
214 | ||
215 | restart: | |
216 | n = rb_first(root); | |
217 | bad = 0; | |
218 | prev = NULL; | |
219 | ||
220 | printk("Block Allocation Reservation Windows Map (%s):\n", fn); | |
221 | while (n) { | |
222 | rsv = rb_entry(n, struct ext2_reserve_window_node, rsv_node); | |
223 | if (verbose) | |
224 | printk("reservation window 0x%p " | |
225 | "start: %lu, end: %lu\n", | |
226 | rsv, rsv->rsv_start, rsv->rsv_end); | |
227 | if (rsv->rsv_start && rsv->rsv_start >= rsv->rsv_end) { | |
228 | printk("Bad reservation %p (start >= end)\n", | |
229 | rsv); | |
230 | bad = 1; | |
231 | } | |
232 | if (prev && prev->rsv_end >= rsv->rsv_start) { | |
233 | printk("Bad reservation %p (prev->end >= start)\n", | |
234 | rsv); | |
235 | bad = 1; | |
236 | } | |
237 | if (bad) { | |
238 | if (!verbose) { | |
239 | printk("Restarting reservation walk in verbose mode\n"); | |
240 | verbose = 1; | |
241 | goto restart; | |
242 | } | |
243 | } | |
244 | n = rb_next(n); | |
245 | prev = rsv; | |
246 | } | |
247 | printk("Window map complete.\n"); | |
2c11619a | 248 | BUG_ON(bad); |
a686cd89 MB |
249 | } |
250 | #define rsv_window_dump(root, verbose) \ | |
251 | __rsv_window_dump((root), (verbose), __FUNCTION__) | |
252 | #else | |
253 | #define rsv_window_dump(root, verbose) do {} while (0) | |
254 | #endif | |
255 | ||
256 | /** | |
257 | * goal_in_my_reservation() | |
258 | * @rsv: inode's reservation window | |
259 | * @grp_goal: given goal block relative to the allocation block group | |
260 | * @group: the current allocation block group | |
261 | * @sb: filesystem super block | |
262 | * | |
263 | * Test if the given goal block (group relative) is within the file's | |
264 | * own block reservation window range. | |
265 | * | |
266 | * If the reservation window is outside the goal allocation group, return 0; | |
267 | * grp_goal (given goal block) could be -1, which means no specific | |
268 | * goal block. In this case, always return 1. | |
269 | * If the goal block is within the reservation window, return 1; | |
270 | * otherwise, return 0; | |
271 | */ | |
272 | static int | |
273 | goal_in_my_reservation(struct ext2_reserve_window *rsv, ext2_grpblk_t grp_goal, | |
274 | unsigned int group, struct super_block * sb) | |
275 | { | |
276 | ext2_fsblk_t group_first_block, group_last_block; | |
277 | ||
278 | group_first_block = ext2_group_first_block_no(sb, group); | |
279 | group_last_block = group_first_block + EXT2_BLOCKS_PER_GROUP(sb) - 1; | |
280 | ||
281 | if ((rsv->_rsv_start > group_last_block) || | |
282 | (rsv->_rsv_end < group_first_block)) | |
283 | return 0; | |
284 | if ((grp_goal >= 0) && ((grp_goal + group_first_block < rsv->_rsv_start) | |
285 | || (grp_goal + group_first_block > rsv->_rsv_end))) | |
286 | return 0; | |
287 | return 1; | |
288 | } | |
289 | ||
290 | /** | |
291 | * search_reserve_window() | |
292 | * @rb_root: root of reservation tree | |
293 | * @goal: target allocation block | |
294 | * | |
295 | * Find the reserved window which includes the goal, or the previous one | |
296 | * if the goal is not in any window. | |
297 | * Returns NULL if there are no windows or if all windows start after the goal. | |
298 | */ | |
299 | static struct ext2_reserve_window_node * | |
300 | search_reserve_window(struct rb_root *root, ext2_fsblk_t goal) | |
301 | { | |
302 | struct rb_node *n = root->rb_node; | |
303 | struct ext2_reserve_window_node *rsv; | |
304 | ||
305 | if (!n) | |
306 | return NULL; | |
307 | ||
308 | do { | |
309 | rsv = rb_entry(n, struct ext2_reserve_window_node, rsv_node); | |
310 | ||
311 | if (goal < rsv->rsv_start) | |
312 | n = n->rb_left; | |
313 | else if (goal > rsv->rsv_end) | |
314 | n = n->rb_right; | |
315 | else | |
316 | return rsv; | |
317 | } while (n); | |
318 | /* | |
319 | * We've fallen off the end of the tree: the goal wasn't inside | |
320 | * any particular node. OK, the previous node must be to one | |
321 | * side of the interval containing the goal. If it's the RHS, | |
322 | * we need to back up one. | |
323 | */ | |
324 | if (rsv->rsv_start > goal) { | |
325 | n = rb_prev(&rsv->rsv_node); | |
326 | rsv = rb_entry(n, struct ext2_reserve_window_node, rsv_node); | |
327 | } | |
328 | return rsv; | |
329 | } | |
330 | ||
331 | /* | |
332 | * ext2_rsv_window_add() -- Insert a window to the block reservation rb tree. | |
333 | * @sb: super block | |
334 | * @rsv: reservation window to add | |
335 | * | |
336 | * Must be called with rsv_lock held. | |
337 | */ | |
338 | void ext2_rsv_window_add(struct super_block *sb, | |
339 | struct ext2_reserve_window_node *rsv) | |
340 | { | |
341 | struct rb_root *root = &EXT2_SB(sb)->s_rsv_window_root; | |
342 | struct rb_node *node = &rsv->rsv_node; | |
343 | ext2_fsblk_t start = rsv->rsv_start; | |
344 | ||
345 | struct rb_node ** p = &root->rb_node; | |
346 | struct rb_node * parent = NULL; | |
347 | struct ext2_reserve_window_node *this; | |
348 | ||
349 | while (*p) | |
350 | { | |
351 | parent = *p; | |
352 | this = rb_entry(parent, struct ext2_reserve_window_node, rsv_node); | |
353 | ||
354 | if (start < this->rsv_start) | |
355 | p = &(*p)->rb_left; | |
356 | else if (start > this->rsv_end) | |
357 | p = &(*p)->rb_right; | |
358 | else { | |
359 | rsv_window_dump(root, 1); | |
360 | BUG(); | |
361 | } | |
362 | } | |
363 | ||
364 | rb_link_node(node, parent, p); | |
365 | rb_insert_color(node, root); | |
366 | } | |
367 | ||
368 | /** | |
369 | * rsv_window_remove() -- unlink a window from the reservation rb tree | |
370 | * @sb: super block | |
371 | * @rsv: reservation window to remove | |
372 | * | |
373 | * Mark the block reservation window as not allocated, and unlink it | |
374 | * from the filesystem reservation window rb tree. Must be called with | |
375 | * rsv_lock held. | |
376 | */ | |
377 | static void rsv_window_remove(struct super_block *sb, | |
378 | struct ext2_reserve_window_node *rsv) | |
379 | { | |
380 | rsv->rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED; | |
381 | rsv->rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED; | |
382 | rsv->rsv_alloc_hit = 0; | |
383 | rb_erase(&rsv->rsv_node, &EXT2_SB(sb)->s_rsv_window_root); | |
384 | } | |
385 | ||
386 | /* | |
387 | * rsv_is_empty() -- Check if the reservation window is allocated. | |
388 | * @rsv: given reservation window to check | |
389 | * | |
390 | * returns 1 if the end block is EXT2_RESERVE_WINDOW_NOT_ALLOCATED. | |
391 | */ | |
392 | static inline int rsv_is_empty(struct ext2_reserve_window *rsv) | |
393 | { | |
394 | /* a valid reservation end block could not be 0 */ | |
395 | return (rsv->_rsv_end == EXT2_RESERVE_WINDOW_NOT_ALLOCATED); | |
396 | } | |
397 | ||
398 | /** | |
399 | * ext2_init_block_alloc_info() | |
400 | * @inode: file inode structure | |
401 | * | |
402 | * Allocate and initialize the reservation window structure, and | |
403 | * link the window to the ext2 inode structure at last | |
404 | * | |
405 | * The reservation window structure is only dynamically allocated | |
406 | * and linked to ext2 inode the first time the open file | |
407 | * needs a new block. So, before every ext2_new_block(s) call, for | |
408 | * regular files, we should check whether the reservation window | |
409 | * structure exists or not. In the latter case, this function is called. | |
410 | * Fail to do so will result in block reservation being turned off for that | |
411 | * open file. | |
412 | * | |
413 | * This function is called from ext2_get_blocks_handle(), also called | |
414 | * when setting the reservation window size through ioctl before the file | |
415 | * is open for write (needs block allocation). | |
416 | * | |
417 | * Needs truncate_mutex protection prior to calling this function. | |
418 | */ | |
419 | void ext2_init_block_alloc_info(struct inode *inode) | |
420 | { | |
421 | struct ext2_inode_info *ei = EXT2_I(inode); | |
422 | struct ext2_block_alloc_info *block_i = ei->i_block_alloc_info; | |
423 | struct super_block *sb = inode->i_sb; | |
424 | ||
425 | block_i = kmalloc(sizeof(*block_i), GFP_NOFS); | |
426 | if (block_i) { | |
427 | struct ext2_reserve_window_node *rsv = &block_i->rsv_window_node; | |
428 | ||
429 | rsv->rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED; | |
430 | rsv->rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED; | |
431 | ||
432 | /* | |
433 | * if filesystem is mounted with NORESERVATION, the goal | |
434 | * reservation window size is set to zero to indicate | |
435 | * block reservation is off | |
436 | */ | |
437 | if (!test_opt(sb, RESERVATION)) | |
438 | rsv->rsv_goal_size = 0; | |
439 | else | |
440 | rsv->rsv_goal_size = EXT2_DEFAULT_RESERVE_BLOCKS; | |
441 | rsv->rsv_alloc_hit = 0; | |
442 | block_i->last_alloc_logical_block = 0; | |
443 | block_i->last_alloc_physical_block = 0; | |
444 | } | |
445 | ei->i_block_alloc_info = block_i; | |
446 | } | |
447 | ||
448 | /** | |
449 | * ext2_discard_reservation() | |
450 | * @inode: inode | |
451 | * | |
452 | * Discard(free) block reservation window on last file close, or truncate | |
453 | * or at last iput(). | |
454 | * | |
455 | * It is being called in three cases: | |
456 | * ext2_release_file(): last writer closes the file | |
457 | * ext2_clear_inode(): last iput(), when nobody links to this file. | |
458 | * ext2_truncate(): when the block indirect map is about to change. | |
459 | */ | |
460 | void ext2_discard_reservation(struct inode *inode) | |
461 | { | |
462 | struct ext2_inode_info *ei = EXT2_I(inode); | |
463 | struct ext2_block_alloc_info *block_i = ei->i_block_alloc_info; | |
464 | struct ext2_reserve_window_node *rsv; | |
465 | spinlock_t *rsv_lock = &EXT2_SB(inode->i_sb)->s_rsv_window_lock; | |
466 | ||
467 | if (!block_i) | |
468 | return; | |
469 | ||
470 | rsv = &block_i->rsv_window_node; | |
471 | if (!rsv_is_empty(&rsv->rsv_window)) { | |
472 | spin_lock(rsv_lock); | |
473 | if (!rsv_is_empty(&rsv->rsv_window)) | |
474 | rsv_window_remove(inode->i_sb, rsv); | |
475 | spin_unlock(rsv_lock); | |
476 | } | |
477 | } | |
478 | ||
479 | /** | |
480 | * ext2_free_blocks_sb() -- Free given blocks and update quota and i_blocks | |
481 | * @inode: inode | |
482 | * @block: start physcial block to free | |
483 | * @count: number of blocks to free | |
484 | */ | |
1da177e4 LT |
485 | void ext2_free_blocks (struct inode * inode, unsigned long block, |
486 | unsigned long count) | |
487 | { | |
488 | struct buffer_head *bitmap_bh = NULL; | |
489 | struct buffer_head * bh2; | |
490 | unsigned long block_group; | |
491 | unsigned long bit; | |
492 | unsigned long i; | |
493 | unsigned long overflow; | |
494 | struct super_block * sb = inode->i_sb; | |
495 | struct ext2_sb_info * sbi = EXT2_SB(sb); | |
496 | struct ext2_group_desc * desc; | |
497 | struct ext2_super_block * es = sbi->s_es; | |
498 | unsigned freed = 0, group_freed; | |
499 | ||
500 | if (block < le32_to_cpu(es->s_first_data_block) || | |
501 | block + count < block || | |
502 | block + count > le32_to_cpu(es->s_blocks_count)) { | |
503 | ext2_error (sb, "ext2_free_blocks", | |
504 | "Freeing blocks not in datazone - " | |
505 | "block = %lu, count = %lu", block, count); | |
506 | goto error_return; | |
507 | } | |
508 | ||
509 | ext2_debug ("freeing block(s) %lu-%lu\n", block, block + count - 1); | |
510 | ||
511 | do_more: | |
512 | overflow = 0; | |
513 | block_group = (block - le32_to_cpu(es->s_first_data_block)) / | |
514 | EXT2_BLOCKS_PER_GROUP(sb); | |
515 | bit = (block - le32_to_cpu(es->s_first_data_block)) % | |
516 | EXT2_BLOCKS_PER_GROUP(sb); | |
517 | /* | |
518 | * Check to see if we are freeing blocks across a group | |
519 | * boundary. | |
520 | */ | |
521 | if (bit + count > EXT2_BLOCKS_PER_GROUP(sb)) { | |
522 | overflow = bit + count - EXT2_BLOCKS_PER_GROUP(sb); | |
523 | count -= overflow; | |
524 | } | |
525 | brelse(bitmap_bh); | |
526 | bitmap_bh = read_block_bitmap(sb, block_group); | |
527 | if (!bitmap_bh) | |
528 | goto error_return; | |
529 | ||
530 | desc = ext2_get_group_desc (sb, block_group, &bh2); | |
531 | if (!desc) | |
532 | goto error_return; | |
533 | ||
534 | if (in_range (le32_to_cpu(desc->bg_block_bitmap), block, count) || | |
535 | in_range (le32_to_cpu(desc->bg_inode_bitmap), block, count) || | |
536 | in_range (block, le32_to_cpu(desc->bg_inode_table), | |
537 | sbi->s_itb_per_group) || | |
538 | in_range (block + count - 1, le32_to_cpu(desc->bg_inode_table), | |
7f0adaec | 539 | sbi->s_itb_per_group)) { |
1da177e4 LT |
540 | ext2_error (sb, "ext2_free_blocks", |
541 | "Freeing blocks in system zones - " | |
542 | "Block = %lu, count = %lu", | |
543 | block, count); | |
7f0adaec AK |
544 | goto error_return; |
545 | } | |
1da177e4 LT |
546 | |
547 | for (i = 0, group_freed = 0; i < count; i++) { | |
548 | if (!ext2_clear_bit_atomic(sb_bgl_lock(sbi, block_group), | |
549 | bit + i, bitmap_bh->b_data)) { | |
550 | ext2_error(sb, __FUNCTION__, | |
551 | "bit already cleared for block %lu", block + i); | |
552 | } else { | |
553 | group_freed++; | |
554 | } | |
555 | } | |
556 | ||
557 | mark_buffer_dirty(bitmap_bh); | |
558 | if (sb->s_flags & MS_SYNCHRONOUS) | |
559 | sync_dirty_buffer(bitmap_bh); | |
560 | ||
a686cd89 | 561 | group_adjust_blocks(sb, block_group, desc, bh2, group_freed); |
1da177e4 LT |
562 | freed += group_freed; |
563 | ||
564 | if (overflow) { | |
565 | block += count; | |
566 | count = overflow; | |
567 | goto do_more; | |
568 | } | |
569 | error_return: | |
570 | brelse(bitmap_bh); | |
571 | release_blocks(sb, freed); | |
572 | DQUOT_FREE_BLOCK(inode, freed); | |
573 | } | |
574 | ||
a686cd89 MB |
575 | /** |
576 | * bitmap_search_next_usable_block() | |
577 | * @start: the starting block (group relative) of the search | |
578 | * @bh: bufferhead contains the block group bitmap | |
579 | * @maxblocks: the ending block (group relative) of the reservation | |
580 | * | |
581 | * The bitmap search --- search forward through the actual bitmap on disk until | |
582 | * we find a bit free. | |
583 | */ | |
584 | static ext2_grpblk_t | |
585 | bitmap_search_next_usable_block(ext2_grpblk_t start, struct buffer_head *bh, | |
586 | ext2_grpblk_t maxblocks) | |
1da177e4 | 587 | { |
a686cd89 | 588 | ext2_grpblk_t next; |
1da177e4 | 589 | |
a686cd89 MB |
590 | next = ext2_find_next_zero_bit(bh->b_data, maxblocks, start); |
591 | if (next >= maxblocks) | |
592 | return -1; | |
593 | return next; | |
594 | } | |
1da177e4 | 595 | |
a686cd89 MB |
596 | /** |
597 | * find_next_usable_block() | |
598 | * @start: the starting block (group relative) to find next | |
599 | * allocatable block in bitmap. | |
600 | * @bh: bufferhead contains the block group bitmap | |
601 | * @maxblocks: the ending block (group relative) for the search | |
602 | * | |
603 | * Find an allocatable block in a bitmap. We perform the "most | |
604 | * appropriate allocation" algorithm of looking for a free block near | |
605 | * the initial goal; then for a free byte somewhere in the bitmap; | |
606 | * then for any free bit in the bitmap. | |
607 | */ | |
608 | static ext2_grpblk_t | |
609 | find_next_usable_block(int start, struct buffer_head *bh, int maxblocks) | |
610 | { | |
611 | ext2_grpblk_t here, next; | |
612 | char *p, *r; | |
613 | ||
614 | if (start > 0) { | |
1da177e4 LT |
615 | /* |
616 | * The goal was occupied; search forward for a free | |
617 | * block within the next XX blocks. | |
618 | * | |
619 | * end_goal is more or less random, but it has to be | |
620 | * less than EXT2_BLOCKS_PER_GROUP. Aligning up to the | |
621 | * next 64-bit boundary is simple.. | |
622 | */ | |
a686cd89 MB |
623 | ext2_grpblk_t end_goal = (start + 63) & ~63; |
624 | if (end_goal > maxblocks) | |
625 | end_goal = maxblocks; | |
626 | here = ext2_find_next_zero_bit(bh->b_data, end_goal, start); | |
627 | if (here < end_goal) | |
628 | return here; | |
629 | ext2_debug("Bit not found near goal\n"); | |
630 | } | |
631 | ||
632 | here = start; | |
633 | if (here < 0) | |
634 | here = 0; | |
635 | ||
636 | p = ((char *)bh->b_data) + (here >> 3); | |
637 | r = memscan(p, 0, ((maxblocks + 7) >> 3) - (here >> 3)); | |
638 | next = (r - ((char *)bh->b_data)) << 3; | |
639 | ||
640 | if (next < maxblocks && next >= here) | |
641 | return next; | |
642 | ||
643 | here = bitmap_search_next_usable_block(here, bh, maxblocks); | |
644 | return here; | |
645 | } | |
646 | ||
647 | /* | |
648 | * ext2_try_to_allocate() | |
649 | * @sb: superblock | |
650 | * @handle: handle to this transaction | |
651 | * @group: given allocation block group | |
652 | * @bitmap_bh: bufferhead holds the block bitmap | |
653 | * @grp_goal: given target block within the group | |
654 | * @count: target number of blocks to allocate | |
655 | * @my_rsv: reservation window | |
656 | * | |
657 | * Attempt to allocate blocks within a give range. Set the range of allocation | |
658 | * first, then find the first free bit(s) from the bitmap (within the range), | |
659 | * and at last, allocate the blocks by claiming the found free bit as allocated. | |
660 | * | |
661 | * To set the range of this allocation: | |
662 | * if there is a reservation window, only try to allocate block(s) | |
663 | * from the file's own reservation window; | |
664 | * Otherwise, the allocation range starts from the give goal block, | |
665 | * ends at the block group's last block. | |
666 | * | |
667 | * If we failed to allocate the desired block then we may end up crossing to a | |
668 | * new bitmap. | |
669 | */ | |
670 | static int | |
671 | ext2_try_to_allocate(struct super_block *sb, int group, | |
672 | struct buffer_head *bitmap_bh, ext2_grpblk_t grp_goal, | |
673 | unsigned long *count, | |
674 | struct ext2_reserve_window *my_rsv) | |
675 | { | |
676 | ext2_fsblk_t group_first_block; | |
677 | ext2_grpblk_t start, end; | |
678 | unsigned long num = 0; | |
679 | ||
680 | /* we do allocation within the reservation window if we have a window */ | |
681 | if (my_rsv) { | |
682 | group_first_block = ext2_group_first_block_no(sb, group); | |
683 | if (my_rsv->_rsv_start >= group_first_block) | |
684 | start = my_rsv->_rsv_start - group_first_block; | |
685 | else | |
686 | /* reservation window cross group boundary */ | |
687 | start = 0; | |
688 | end = my_rsv->_rsv_end - group_first_block + 1; | |
689 | if (end > EXT2_BLOCKS_PER_GROUP(sb)) | |
690 | /* reservation window crosses group boundary */ | |
691 | end = EXT2_BLOCKS_PER_GROUP(sb); | |
692 | if ((start <= grp_goal) && (grp_goal < end)) | |
693 | start = grp_goal; | |
694 | else | |
695 | grp_goal = -1; | |
696 | } else { | |
697 | if (grp_goal > 0) | |
698 | start = grp_goal; | |
699 | else | |
700 | start = 0; | |
701 | end = EXT2_BLOCKS_PER_GROUP(sb); | |
702 | } | |
703 | ||
704 | BUG_ON(start > EXT2_BLOCKS_PER_GROUP(sb)); | |
705 | ||
706 | repeat: | |
707 | if (grp_goal < 0) { | |
708 | grp_goal = find_next_usable_block(start, bitmap_bh, end); | |
709 | if (grp_goal < 0) | |
710 | goto fail_access; | |
711 | if (!my_rsv) { | |
712 | int i; | |
713 | ||
714 | for (i = 0; i < 7 && grp_goal > start && | |
715 | !ext2_test_bit(grp_goal - 1, | |
716 | bitmap_bh->b_data); | |
717 | i++, grp_goal--) | |
718 | ; | |
719 | } | |
720 | } | |
721 | start = grp_goal; | |
722 | ||
723 | if (ext2_set_bit_atomic(sb_bgl_lock(EXT2_SB(sb), group), grp_goal, | |
724 | bitmap_bh->b_data)) { | |
725 | /* | |
726 | * The block was allocated by another thread, or it was | |
727 | * allocated and then freed by another thread | |
728 | */ | |
729 | start++; | |
730 | grp_goal++; | |
731 | if (start >= end) | |
732 | goto fail_access; | |
733 | goto repeat; | |
734 | } | |
735 | num++; | |
736 | grp_goal++; | |
737 | while (num < *count && grp_goal < end | |
738 | && !ext2_set_bit_atomic(sb_bgl_lock(EXT2_SB(sb), group), | |
739 | grp_goal, bitmap_bh->b_data)) { | |
740 | num++; | |
741 | grp_goal++; | |
742 | } | |
743 | *count = num; | |
744 | return grp_goal - num; | |
745 | fail_access: | |
746 | *count = num; | |
747 | return -1; | |
748 | } | |
749 | ||
750 | /** | |
751 | * find_next_reservable_window(): | |
752 | * find a reservable space within the given range. | |
753 | * It does not allocate the reservation window for now: | |
754 | * alloc_new_reservation() will do the work later. | |
755 | * | |
756 | * @search_head: the head of the searching list; | |
757 | * This is not necessarily the list head of the whole filesystem | |
758 | * | |
759 | * We have both head and start_block to assist the search | |
760 | * for the reservable space. The list starts from head, | |
761 | * but we will shift to the place where start_block is, | |
762 | * then start from there, when looking for a reservable space. | |
763 | * | |
764 | * @size: the target new reservation window size | |
765 | * | |
766 | * @group_first_block: the first block we consider to start | |
767 | * the real search from | |
768 | * | |
769 | * @last_block: | |
770 | * the maximum block number that our goal reservable space | |
771 | * could start from. This is normally the last block in this | |
772 | * group. The search will end when we found the start of next | |
773 | * possible reservable space is out of this boundary. | |
774 | * This could handle the cross boundary reservation window | |
775 | * request. | |
776 | * | |
777 | * basically we search from the given range, rather than the whole | |
778 | * reservation double linked list, (start_block, last_block) | |
779 | * to find a free region that is of my size and has not | |
780 | * been reserved. | |
781 | * | |
782 | */ | |
783 | static int find_next_reservable_window( | |
784 | struct ext2_reserve_window_node *search_head, | |
785 | struct ext2_reserve_window_node *my_rsv, | |
786 | struct super_block * sb, | |
787 | ext2_fsblk_t start_block, | |
788 | ext2_fsblk_t last_block) | |
789 | { | |
790 | struct rb_node *next; | |
791 | struct ext2_reserve_window_node *rsv, *prev; | |
792 | ext2_fsblk_t cur; | |
793 | int size = my_rsv->rsv_goal_size; | |
794 | ||
795 | /* TODO: make the start of the reservation window byte-aligned */ | |
796 | /* cur = *start_block & ~7;*/ | |
797 | cur = start_block; | |
798 | rsv = search_head; | |
799 | if (!rsv) | |
800 | return -1; | |
801 | ||
802 | while (1) { | |
803 | if (cur <= rsv->rsv_end) | |
804 | cur = rsv->rsv_end + 1; | |
805 | ||
806 | /* TODO? | |
807 | * in the case we could not find a reservable space | |
808 | * that is what is expected, during the re-search, we could | |
809 | * remember what's the largest reservable space we could have | |
810 | * and return that one. | |
811 | * | |
812 | * For now it will fail if we could not find the reservable | |
813 | * space with expected-size (or more)... | |
814 | */ | |
815 | if (cur > last_block) | |
816 | return -1; /* fail */ | |
817 | ||
818 | prev = rsv; | |
819 | next = rb_next(&rsv->rsv_node); | |
820 | rsv = rb_entry(next,struct ext2_reserve_window_node,rsv_node); | |
821 | ||
1da177e4 | 822 | /* |
a686cd89 MB |
823 | * Reached the last reservation, we can just append to the |
824 | * previous one. | |
1da177e4 | 825 | */ |
a686cd89 MB |
826 | if (!next) |
827 | break; | |
828 | ||
829 | if (cur + size <= rsv->rsv_start) { | |
830 | /* | |
831 | * Found a reserveable space big enough. We could | |
832 | * have a reservation across the group boundary here | |
833 | */ | |
834 | break; | |
835 | } | |
1da177e4 | 836 | } |
a686cd89 MB |
837 | /* |
838 | * we come here either : | |
839 | * when we reach the end of the whole list, | |
840 | * and there is empty reservable space after last entry in the list. | |
841 | * append it to the end of the list. | |
842 | * | |
843 | * or we found one reservable space in the middle of the list, | |
844 | * return the reservation window that we could append to. | |
845 | * succeed. | |
846 | */ | |
847 | ||
848 | if ((prev != my_rsv) && (!rsv_is_empty(&my_rsv->rsv_window))) | |
849 | rsv_window_remove(sb, my_rsv); | |
850 | ||
851 | /* | |
852 | * Let's book the whole avaliable window for now. We will check the | |
853 | * disk bitmap later and then, if there are free blocks then we adjust | |
854 | * the window size if it's larger than requested. | |
855 | * Otherwise, we will remove this node from the tree next time | |
856 | * call find_next_reservable_window. | |
857 | */ | |
858 | my_rsv->rsv_start = cur; | |
859 | my_rsv->rsv_end = cur + size - 1; | |
860 | my_rsv->rsv_alloc_hit = 0; | |
861 | ||
862 | if (prev != my_rsv) | |
863 | ext2_rsv_window_add(sb, my_rsv); | |
864 | ||
865 | return 0; | |
866 | } | |
867 | ||
868 | /** | |
869 | * alloc_new_reservation()--allocate a new reservation window | |
870 | * | |
871 | * To make a new reservation, we search part of the filesystem | |
872 | * reservation list (the list that inside the group). We try to | |
873 | * allocate a new reservation window near the allocation goal, | |
874 | * or the beginning of the group, if there is no goal. | |
875 | * | |
876 | * We first find a reservable space after the goal, then from | |
877 | * there, we check the bitmap for the first free block after | |
878 | * it. If there is no free block until the end of group, then the | |
879 | * whole group is full, we failed. Otherwise, check if the free | |
880 | * block is inside the expected reservable space, if so, we | |
881 | * succeed. | |
882 | * If the first free block is outside the reservable space, then | |
883 | * start from the first free block, we search for next available | |
884 | * space, and go on. | |
885 | * | |
886 | * on succeed, a new reservation will be found and inserted into the list | |
887 | * It contains at least one free block, and it does not overlap with other | |
888 | * reservation windows. | |
889 | * | |
890 | * failed: we failed to find a reservation window in this group | |
891 | * | |
892 | * @rsv: the reservation | |
893 | * | |
894 | * @grp_goal: The goal (group-relative). It is where the search for a | |
895 | * free reservable space should start from. | |
896 | * if we have a goal(goal >0 ), then start from there, | |
897 | * no goal(goal = -1), we start from the first block | |
898 | * of the group. | |
899 | * | |
900 | * @sb: the super block | |
901 | * @group: the group we are trying to allocate in | |
902 | * @bitmap_bh: the block group block bitmap | |
903 | * | |
904 | */ | |
905 | static int alloc_new_reservation(struct ext2_reserve_window_node *my_rsv, | |
906 | ext2_grpblk_t grp_goal, struct super_block *sb, | |
907 | unsigned int group, struct buffer_head *bitmap_bh) | |
908 | { | |
909 | struct ext2_reserve_window_node *search_head; | |
910 | ext2_fsblk_t group_first_block, group_end_block, start_block; | |
911 | ext2_grpblk_t first_free_block; | |
912 | struct rb_root *fs_rsv_root = &EXT2_SB(sb)->s_rsv_window_root; | |
913 | unsigned long size; | |
914 | int ret; | |
915 | spinlock_t *rsv_lock = &EXT2_SB(sb)->s_rsv_window_lock; | |
916 | ||
917 | group_first_block = ext2_group_first_block_no(sb, group); | |
918 | group_end_block = group_first_block + (EXT2_BLOCKS_PER_GROUP(sb) - 1); | |
1da177e4 | 919 | |
a686cd89 MB |
920 | if (grp_goal < 0) |
921 | start_block = group_first_block; | |
922 | else | |
923 | start_block = grp_goal + group_first_block; | |
924 | ||
925 | size = my_rsv->rsv_goal_size; | |
926 | ||
927 | if (!rsv_is_empty(&my_rsv->rsv_window)) { | |
928 | /* | |
929 | * if the old reservation is cross group boundary | |
930 | * and if the goal is inside the old reservation window, | |
931 | * we will come here when we just failed to allocate from | |
932 | * the first part of the window. We still have another part | |
933 | * that belongs to the next group. In this case, there is no | |
934 | * point to discard our window and try to allocate a new one | |
935 | * in this group(which will fail). we should | |
936 | * keep the reservation window, just simply move on. | |
937 | * | |
938 | * Maybe we could shift the start block of the reservation | |
939 | * window to the first block of next group. | |
1da177e4 | 940 | */ |
a686cd89 MB |
941 | |
942 | if ((my_rsv->rsv_start <= group_end_block) && | |
943 | (my_rsv->rsv_end > group_end_block) && | |
944 | (start_block >= my_rsv->rsv_start)) | |
945 | return -1; | |
946 | ||
947 | if ((my_rsv->rsv_alloc_hit > | |
948 | (my_rsv->rsv_end - my_rsv->rsv_start + 1) / 2)) { | |
949 | /* | |
950 | * if the previously allocation hit ratio is | |
951 | * greater than 1/2, then we double the size of | |
952 | * the reservation window the next time, | |
953 | * otherwise we keep the same size window | |
954 | */ | |
955 | size = size * 2; | |
956 | if (size > EXT2_MAX_RESERVE_BLOCKS) | |
957 | size = EXT2_MAX_RESERVE_BLOCKS; | |
958 | my_rsv->rsv_goal_size= size; | |
959 | } | |
1da177e4 LT |
960 | } |
961 | ||
a686cd89 MB |
962 | spin_lock(rsv_lock); |
963 | /* | |
964 | * shift the search start to the window near the goal block | |
965 | */ | |
966 | search_head = search_reserve_window(fs_rsv_root, start_block); | |
967 | ||
968 | /* | |
969 | * find_next_reservable_window() simply finds a reservable window | |
970 | * inside the given range(start_block, group_end_block). | |
971 | * | |
972 | * To make sure the reservation window has a free bit inside it, we | |
973 | * need to check the bitmap after we found a reservable window. | |
974 | */ | |
975 | retry: | |
976 | ret = find_next_reservable_window(search_head, my_rsv, sb, | |
977 | start_block, group_end_block); | |
978 | ||
979 | if (ret == -1) { | |
980 | if (!rsv_is_empty(&my_rsv->rsv_window)) | |
981 | rsv_window_remove(sb, my_rsv); | |
982 | spin_unlock(rsv_lock); | |
983 | return -1; | |
1da177e4 | 984 | } |
a686cd89 MB |
985 | |
986 | /* | |
987 | * On success, find_next_reservable_window() returns the | |
988 | * reservation window where there is a reservable space after it. | |
989 | * Before we reserve this reservable space, we need | |
990 | * to make sure there is at least a free block inside this region. | |
991 | * | |
992 | * Search the first free bit on the block bitmap. Search starts from | |
993 | * the start block of the reservable space we just found. | |
994 | */ | |
995 | spin_unlock(rsv_lock); | |
996 | first_free_block = bitmap_search_next_usable_block( | |
997 | my_rsv->rsv_start - group_first_block, | |
998 | bitmap_bh, group_end_block - group_first_block + 1); | |
999 | ||
1000 | if (first_free_block < 0) { | |
1001 | /* | |
1002 | * no free block left on the bitmap, no point | |
1003 | * to reserve the space. return failed. | |
1004 | */ | |
1005 | spin_lock(rsv_lock); | |
1006 | if (!rsv_is_empty(&my_rsv->rsv_window)) | |
1007 | rsv_window_remove(sb, my_rsv); | |
1008 | spin_unlock(rsv_lock); | |
1009 | return -1; /* failed */ | |
1010 | } | |
1011 | ||
1012 | start_block = first_free_block + group_first_block; | |
1013 | /* | |
1014 | * check if the first free block is within the | |
1015 | * free space we just reserved | |
1016 | */ | |
1017 | if (start_block >= my_rsv->rsv_start && start_block <= my_rsv->rsv_end) | |
1018 | return 0; /* success */ | |
1019 | /* | |
1020 | * if the first free bit we found is out of the reservable space | |
1021 | * continue search for next reservable space, | |
1022 | * start from where the free block is, | |
1023 | * we also shift the list head to where we stopped last time | |
1024 | */ | |
1025 | search_head = my_rsv; | |
1026 | spin_lock(rsv_lock); | |
1027 | goto retry; | |
1028 | } | |
1029 | ||
1030 | /** | |
1031 | * try_to_extend_reservation() | |
1032 | * @my_rsv: given reservation window | |
1033 | * @sb: super block | |
1034 | * @size: the delta to extend | |
1035 | * | |
1036 | * Attempt to expand the reservation window large enough to have | |
1037 | * required number of free blocks | |
1038 | * | |
1039 | * Since ext2_try_to_allocate() will always allocate blocks within | |
1040 | * the reservation window range, if the window size is too small, | |
1041 | * multiple blocks allocation has to stop at the end of the reservation | |
1042 | * window. To make this more efficient, given the total number of | |
1043 | * blocks needed and the current size of the window, we try to | |
1044 | * expand the reservation window size if necessary on a best-effort | |
1045 | * basis before ext2_new_blocks() tries to allocate blocks. | |
1046 | */ | |
1047 | static void try_to_extend_reservation(struct ext2_reserve_window_node *my_rsv, | |
1048 | struct super_block *sb, int size) | |
1049 | { | |
1050 | struct ext2_reserve_window_node *next_rsv; | |
1051 | struct rb_node *next; | |
1052 | spinlock_t *rsv_lock = &EXT2_SB(sb)->s_rsv_window_lock; | |
1053 | ||
1054 | if (!spin_trylock(rsv_lock)) | |
1055 | return; | |
1056 | ||
1057 | next = rb_next(&my_rsv->rsv_node); | |
1058 | ||
1059 | if (!next) | |
1060 | my_rsv->rsv_end += size; | |
1061 | else { | |
1062 | next_rsv = rb_entry(next, struct ext2_reserve_window_node, rsv_node); | |
1063 | ||
1064 | if ((next_rsv->rsv_start - my_rsv->rsv_end - 1) >= size) | |
1065 | my_rsv->rsv_end += size; | |
1066 | else | |
1067 | my_rsv->rsv_end = next_rsv->rsv_start - 1; | |
1068 | } | |
1069 | spin_unlock(rsv_lock); | |
1070 | } | |
1071 | ||
1072 | /** | |
1073 | * ext2_try_to_allocate_with_rsv() | |
1074 | * @sb: superblock | |
1075 | * @group: given allocation block group | |
1076 | * @bitmap_bh: bufferhead holds the block bitmap | |
1077 | * @grp_goal: given target block within the group | |
1078 | * @count: target number of blocks to allocate | |
1079 | * @my_rsv: reservation window | |
1080 | * | |
1081 | * This is the main function used to allocate a new block and its reservation | |
1082 | * window. | |
1083 | * | |
1084 | * Each time when a new block allocation is need, first try to allocate from | |
1085 | * its own reservation. If it does not have a reservation window, instead of | |
1086 | * looking for a free bit on bitmap first, then look up the reservation list to | |
1087 | * see if it is inside somebody else's reservation window, we try to allocate a | |
1088 | * reservation window for it starting from the goal first. Then do the block | |
1089 | * allocation within the reservation window. | |
1090 | * | |
1091 | * This will avoid keeping on searching the reservation list again and | |
1092 | * again when somebody is looking for a free block (without | |
1093 | * reservation), and there are lots of free blocks, but they are all | |
1094 | * being reserved. | |
1095 | * | |
1096 | * We use a red-black tree for the per-filesystem reservation list. | |
1097 | */ | |
1098 | static ext2_grpblk_t | |
1099 | ext2_try_to_allocate_with_rsv(struct super_block *sb, unsigned int group, | |
1100 | struct buffer_head *bitmap_bh, ext2_grpblk_t grp_goal, | |
1101 | struct ext2_reserve_window_node * my_rsv, | |
1102 | unsigned long *count) | |
1103 | { | |
1104 | ext2_fsblk_t group_first_block, group_last_block; | |
1105 | ext2_grpblk_t ret = 0; | |
1106 | unsigned long num = *count; | |
1107 | ||
1108 | /* | |
1109 | * we don't deal with reservation when | |
1110 | * filesystem is mounted without reservation | |
1111 | * or the file is not a regular file | |
1112 | * or last attempt to allocate a block with reservation turned on failed | |
1113 | */ | |
1114 | if (my_rsv == NULL) { | |
1115 | return ext2_try_to_allocate(sb, group, bitmap_bh, | |
1116 | grp_goal, count, NULL); | |
1117 | } | |
1118 | /* | |
1119 | * grp_goal is a group relative block number (if there is a goal) | |
1120 | * 0 <= grp_goal < EXT2_BLOCKS_PER_GROUP(sb) | |
1121 | * first block is a filesystem wide block number | |
1122 | * first block is the block number of the first block in this group | |
1123 | */ | |
1124 | group_first_block = ext2_group_first_block_no(sb, group); | |
1125 | group_last_block = group_first_block + (EXT2_BLOCKS_PER_GROUP(sb) - 1); | |
1126 | ||
1127 | /* | |
1128 | * Basically we will allocate a new block from inode's reservation | |
1129 | * window. | |
1130 | * | |
1131 | * We need to allocate a new reservation window, if: | |
1132 | * a) inode does not have a reservation window; or | |
1133 | * b) last attempt to allocate a block from existing reservation | |
1134 | * failed; or | |
1135 | * c) we come here with a goal and with a reservation window | |
1136 | * | |
1137 | * We do not need to allocate a new reservation window if we come here | |
1138 | * at the beginning with a goal and the goal is inside the window, or | |
1139 | * we don't have a goal but already have a reservation window. | |
1140 | * then we could go to allocate from the reservation window directly. | |
1141 | */ | |
1142 | while (1) { | |
1143 | if (rsv_is_empty(&my_rsv->rsv_window) || (ret < 0) || | |
1144 | !goal_in_my_reservation(&my_rsv->rsv_window, | |
1145 | grp_goal, group, sb)) { | |
1146 | if (my_rsv->rsv_goal_size < *count) | |
1147 | my_rsv->rsv_goal_size = *count; | |
1148 | ret = alloc_new_reservation(my_rsv, grp_goal, sb, | |
1149 | group, bitmap_bh); | |
1150 | if (ret < 0) | |
1151 | break; /* failed */ | |
1152 | ||
1153 | if (!goal_in_my_reservation(&my_rsv->rsv_window, | |
1154 | grp_goal, group, sb)) | |
1155 | grp_goal = -1; | |
1156 | } else if (grp_goal >= 0) { | |
1157 | int curr = my_rsv->rsv_end - | |
1158 | (grp_goal + group_first_block) + 1; | |
1159 | ||
1160 | if (curr < *count) | |
1161 | try_to_extend_reservation(my_rsv, sb, | |
1162 | *count - curr); | |
1163 | } | |
1164 | ||
1165 | if ((my_rsv->rsv_start > group_last_block) || | |
1166 | (my_rsv->rsv_end < group_first_block)) { | |
1167 | rsv_window_dump(&EXT2_SB(sb)->s_rsv_window_root, 1); | |
1168 | BUG(); | |
1169 | } | |
1170 | ret = ext2_try_to_allocate(sb, group, bitmap_bh, grp_goal, | |
1171 | &num, &my_rsv->rsv_window); | |
1172 | if (ret >= 0) { | |
1173 | my_rsv->rsv_alloc_hit += num; | |
1174 | *count = num; | |
1175 | break; /* succeed */ | |
1176 | } | |
1177 | num = *count; | |
1178 | } | |
1179 | return ret; | |
1180 | } | |
1181 | ||
1182 | /** | |
1183 | * ext2_has_free_blocks() | |
1184 | * @sbi: in-core super block structure. | |
1185 | * | |
1186 | * Check if filesystem has at least 1 free block available for allocation. | |
1187 | */ | |
1188 | static int ext2_has_free_blocks(struct ext2_sb_info *sbi) | |
1189 | { | |
1190 | ext2_fsblk_t free_blocks, root_blocks; | |
1191 | ||
1192 | free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter); | |
1193 | root_blocks = le32_to_cpu(sbi->s_es->s_r_blocks_count); | |
1194 | if (free_blocks < root_blocks + 1 && !capable(CAP_SYS_RESOURCE) && | |
1195 | sbi->s_resuid != current->fsuid && | |
1196 | (sbi->s_resgid == 0 || !in_group_p (sbi->s_resgid))) { | |
1197 | return 0; | |
1198 | } | |
1199 | return 1; | |
1da177e4 LT |
1200 | } |
1201 | ||
1202 | /* | |
a686cd89 MB |
1203 | * ext2_new_blocks() -- core block(s) allocation function |
1204 | * @inode: file inode | |
1205 | * @goal: given target block(filesystem wide) | |
1206 | * @count: target number of blocks to allocate | |
1207 | * @errp: error code | |
1208 | * | |
1209 | * ext2_new_blocks uses a goal block to assist allocation. If the goal is | |
1da177e4 LT |
1210 | * free, or there is a free block within 32 blocks of the goal, that block |
1211 | * is allocated. Otherwise a forward search is made for a free block; within | |
1212 | * each block group the search first looks for an entire free byte in the block | |
1213 | * bitmap, and then for any free bit if that fails. | |
1214 | * This function also updates quota and i_blocks field. | |
1215 | */ | |
a686cd89 MB |
1216 | ext2_fsblk_t ext2_new_blocks(struct inode *inode, ext2_fsblk_t goal, |
1217 | unsigned long *count, int *errp) | |
1da177e4 LT |
1218 | { |
1219 | struct buffer_head *bitmap_bh = NULL; | |
a686cd89 MB |
1220 | struct buffer_head *gdp_bh; |
1221 | int group_no; | |
1222 | int goal_group; | |
1223 | ext2_grpblk_t grp_target_blk; /* blockgroup relative goal block */ | |
1224 | ext2_grpblk_t grp_alloc_blk; /* blockgroup-relative allocated block*/ | |
1225 | ext2_fsblk_t ret_block; /* filesyetem-wide allocated block */ | |
1226 | int bgi; /* blockgroup iteration index */ | |
1227 | int performed_allocation = 0; | |
1228 | ext2_grpblk_t free_blocks; /* number of free blocks in a group */ | |
1229 | struct super_block *sb; | |
1230 | struct ext2_group_desc *gdp; | |
1231 | struct ext2_super_block *es; | |
1232 | struct ext2_sb_info *sbi; | |
1233 | struct ext2_reserve_window_node *my_rsv = NULL; | |
1234 | struct ext2_block_alloc_info *block_i; | |
1235 | unsigned short windowsz = 0; | |
1236 | unsigned long ngroups; | |
1237 | unsigned long num = *count; | |
1238 | ||
1239 | *errp = -ENOSPC; | |
1240 | sb = inode->i_sb; | |
1241 | if (!sb) { | |
1242 | printk("ext2_new_blocks: nonexistent device"); | |
1243 | return 0; | |
1da177e4 LT |
1244 | } |
1245 | ||
a686cd89 MB |
1246 | /* |
1247 | * Check quota for allocation of this block. | |
1248 | */ | |
1249 | if (DQUOT_ALLOC_BLOCK(inode, num)) { | |
1250 | *errp = -EDQUOT; | |
1251 | return 0; | |
1252 | } | |
1da177e4 | 1253 | |
a686cd89 MB |
1254 | sbi = EXT2_SB(sb); |
1255 | es = EXT2_SB(sb)->s_es; | |
1256 | ext2_debug("goal=%lu.\n", goal); | |
1257 | /* | |
1258 | * Allocate a block from reservation only when | |
1259 | * filesystem is mounted with reservation(default,-o reservation), and | |
1260 | * it's a regular file, and | |
1261 | * the desired window size is greater than 0 (One could use ioctl | |
1262 | * command EXT2_IOC_SETRSVSZ to set the window size to 0 to turn off | |
1263 | * reservation on that particular file) | |
1264 | */ | |
1265 | block_i = EXT2_I(inode)->i_block_alloc_info; | |
1266 | if (block_i) { | |
1267 | windowsz = block_i->rsv_window_node.rsv_goal_size; | |
1268 | if (windowsz > 0) | |
1269 | my_rsv = &block_i->rsv_window_node; | |
1da177e4 LT |
1270 | } |
1271 | ||
a686cd89 MB |
1272 | if (!ext2_has_free_blocks(sbi)) { |
1273 | *errp = -ENOSPC; | |
1274 | goto out; | |
1275 | } | |
1da177e4 | 1276 | |
a686cd89 MB |
1277 | /* |
1278 | * First, test whether the goal block is free. | |
1279 | */ | |
1da177e4 LT |
1280 | if (goal < le32_to_cpu(es->s_first_data_block) || |
1281 | goal >= le32_to_cpu(es->s_blocks_count)) | |
1282 | goal = le32_to_cpu(es->s_first_data_block); | |
a686cd89 MB |
1283 | group_no = (goal - le32_to_cpu(es->s_first_data_block)) / |
1284 | EXT2_BLOCKS_PER_GROUP(sb); | |
1285 | goal_group = group_no; | |
1286 | retry_alloc: | |
1287 | gdp = ext2_get_group_desc(sb, group_no, &gdp_bh); | |
1288 | if (!gdp) | |
1da177e4 | 1289 | goto io_error; |
1da177e4 | 1290 | |
a686cd89 MB |
1291 | free_blocks = le16_to_cpu(gdp->bg_free_blocks_count); |
1292 | /* | |
1293 | * if there is not enough free blocks to make a new resevation | |
1294 | * turn off reservation for this allocation | |
1295 | */ | |
1296 | if (my_rsv && (free_blocks < windowsz) | |
1297 | && (rsv_is_empty(&my_rsv->rsv_window))) | |
1298 | my_rsv = NULL; | |
1299 | ||
1300 | if (free_blocks > 0) { | |
1301 | grp_target_blk = ((goal - le32_to_cpu(es->s_first_data_block)) % | |
1302 | EXT2_BLOCKS_PER_GROUP(sb)); | |
1da177e4 LT |
1303 | bitmap_bh = read_block_bitmap(sb, group_no); |
1304 | if (!bitmap_bh) | |
1305 | goto io_error; | |
a686cd89 MB |
1306 | grp_alloc_blk = ext2_try_to_allocate_with_rsv(sb, group_no, |
1307 | bitmap_bh, grp_target_blk, | |
1308 | my_rsv, &num); | |
1309 | if (grp_alloc_blk >= 0) | |
1310 | goto allocated; | |
1da177e4 LT |
1311 | } |
1312 | ||
a686cd89 MB |
1313 | ngroups = EXT2_SB(sb)->s_groups_count; |
1314 | smp_rmb(); | |
1da177e4 LT |
1315 | |
1316 | /* | |
144704e5 AM |
1317 | * Now search the rest of the groups. We assume that |
1318 | * group_no and gdp correctly point to the last group visited. | |
1da177e4 | 1319 | */ |
a686cd89 | 1320 | for (bgi = 0; bgi < ngroups; bgi++) { |
1da177e4 | 1321 | group_no++; |
a686cd89 | 1322 | if (group_no >= ngroups) |
1da177e4 | 1323 | group_no = 0; |
a686cd89 MB |
1324 | gdp = ext2_get_group_desc(sb, group_no, &gdp_bh); |
1325 | if (!gdp) | |
1da177e4 | 1326 | goto io_error; |
1da177e4 | 1327 | |
a686cd89 | 1328 | free_blocks = le16_to_cpu(gdp->bg_free_blocks_count); |
1da177e4 | 1329 | /* |
a686cd89 MB |
1330 | * skip this group if the number of |
1331 | * free blocks is less than half of the reservation | |
1332 | * window size. | |
1da177e4 | 1333 | */ |
a686cd89 MB |
1334 | if (free_blocks <= (windowsz/2)) |
1335 | continue; | |
1336 | ||
1337 | brelse(bitmap_bh); | |
1338 | bitmap_bh = read_block_bitmap(sb, group_no); | |
1339 | if (!bitmap_bh) | |
1da177e4 | 1340 | goto io_error; |
1da177e4 | 1341 | /* |
a686cd89 | 1342 | * try to allocate block(s) from this group, without a goal(-1). |
1da177e4 | 1343 | */ |
a686cd89 MB |
1344 | grp_alloc_blk = ext2_try_to_allocate_with_rsv(sb, group_no, |
1345 | bitmap_bh, -1, my_rsv, &num); | |
1346 | if (grp_alloc_blk >= 0) | |
1347 | goto allocated; | |
1348 | } | |
1349 | /* | |
1350 | * We may end up a bogus ealier ENOSPC error due to | |
1351 | * filesystem is "full" of reservations, but | |
1352 | * there maybe indeed free blocks avaliable on disk | |
1353 | * In this case, we just forget about the reservations | |
1354 | * just do block allocation as without reservations. | |
1355 | */ | |
1356 | if (my_rsv) { | |
1357 | my_rsv = NULL; | |
1358 | windowsz = 0; | |
1359 | group_no = goal_group; | |
1360 | goto retry_alloc; | |
1da177e4 | 1361 | } |
a686cd89 MB |
1362 | /* No space left on the device */ |
1363 | *errp = -ENOSPC; | |
1364 | goto out; | |
1365 | ||
1366 | allocated: | |
1da177e4 | 1367 | |
1da177e4 | 1368 | ext2_debug("using block group %d(%d)\n", |
a686cd89 | 1369 | group_no, gdp->bg_free_blocks_count); |
1da177e4 | 1370 | |
a686cd89 | 1371 | ret_block = grp_alloc_blk + ext2_group_first_block_no(sb, group_no); |
1da177e4 | 1372 | |
a686cd89 MB |
1373 | if (in_range(le32_to_cpu(gdp->bg_block_bitmap), ret_block, num) || |
1374 | in_range(le32_to_cpu(gdp->bg_inode_bitmap), ret_block, num) || | |
1375 | in_range(ret_block, le32_to_cpu(gdp->bg_inode_table), | |
1376 | EXT2_SB(sb)->s_itb_per_group) || | |
1377 | in_range(ret_block + num - 1, le32_to_cpu(gdp->bg_inode_table), | |
7f0adaec | 1378 | EXT2_SB(sb)->s_itb_per_group)) { |
a686cd89 | 1379 | ext2_error(sb, "ext2_new_blocks", |
1da177e4 | 1380 | "Allocating block in system zone - " |
a686cd89 MB |
1381 | "blocks from "E2FSBLK", length %lu", |
1382 | ret_block, num); | |
7f0adaec AK |
1383 | goto out; |
1384 | } | |
a686cd89 MB |
1385 | |
1386 | performed_allocation = 1; | |
1da177e4 | 1387 | |
a686cd89 MB |
1388 | if (ret_block + num - 1 >= le32_to_cpu(es->s_blocks_count)) { |
1389 | ext2_error(sb, "ext2_new_blocks", | |
1390 | "block("E2FSBLK") >= blocks count(%d) - " | |
1da177e4 LT |
1391 | "block_group = %d, es == %p ", ret_block, |
1392 | le32_to_cpu(es->s_blocks_count), group_no, es); | |
a686cd89 | 1393 | goto out; |
1da177e4 | 1394 | } |
1da177e4 | 1395 | |
a686cd89 MB |
1396 | group_adjust_blocks(sb, group_no, gdp, gdp_bh, -num); |
1397 | percpu_counter_sub(&sbi->s_freeblocks_counter, num); | |
1da177e4 LT |
1398 | |
1399 | mark_buffer_dirty(bitmap_bh); | |
1400 | if (sb->s_flags & MS_SYNCHRONOUS) | |
1401 | sync_dirty_buffer(bitmap_bh); | |
1402 | ||
a686cd89 MB |
1403 | *errp = 0; |
1404 | brelse(bitmap_bh); | |
1405 | DQUOT_FREE_BLOCK(inode, *count-num); | |
1406 | *count = num; | |
1407 | return ret_block; | |
1da177e4 | 1408 | |
a686cd89 MB |
1409 | io_error: |
1410 | *errp = -EIO; | |
1da177e4 | 1411 | out: |
a686cd89 MB |
1412 | /* |
1413 | * Undo the block allocation | |
1414 | */ | |
1415 | if (!performed_allocation) | |
1416 | DQUOT_FREE_BLOCK(inode, *count); | |
1da177e4 | 1417 | brelse(bitmap_bh); |
a686cd89 MB |
1418 | return 0; |
1419 | } | |
1da177e4 | 1420 | |
a686cd89 MB |
1421 | ext2_fsblk_t ext2_new_block(struct inode *inode, unsigned long goal, int *errp) |
1422 | { | |
1423 | unsigned long count = 1; | |
1424 | ||
1425 | return ext2_new_blocks(inode, goal, &count, errp); | |
1da177e4 LT |
1426 | } |
1427 | ||
21730eed VH |
1428 | #ifdef EXT2FS_DEBUG |
1429 | ||
febfcf91 | 1430 | static const int nibblemap[] = {4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0}; |
21730eed VH |
1431 | |
1432 | unsigned long ext2_count_free (struct buffer_head * map, unsigned int numchars) | |
1433 | { | |
1434 | unsigned int i; | |
1435 | unsigned long sum = 0; | |
1436 | ||
1437 | if (!map) | |
1438 | return (0); | |
1439 | for (i = 0; i < numchars; i++) | |
1440 | sum += nibblemap[map->b_data[i] & 0xf] + | |
1441 | nibblemap[(map->b_data[i] >> 4) & 0xf]; | |
1442 | return (sum); | |
1443 | } | |
1444 | ||
1445 | #endif /* EXT2FS_DEBUG */ | |
1446 | ||
1da177e4 LT |
1447 | unsigned long ext2_count_free_blocks (struct super_block * sb) |
1448 | { | |
1449 | struct ext2_group_desc * desc; | |
1450 | unsigned long desc_count = 0; | |
1451 | int i; | |
1452 | #ifdef EXT2FS_DEBUG | |
1453 | unsigned long bitmap_count, x; | |
1454 | struct ext2_super_block *es; | |
1455 | ||
1da177e4 LT |
1456 | es = EXT2_SB(sb)->s_es; |
1457 | desc_count = 0; | |
1458 | bitmap_count = 0; | |
1459 | desc = NULL; | |
1460 | for (i = 0; i < EXT2_SB(sb)->s_groups_count; i++) { | |
1461 | struct buffer_head *bitmap_bh; | |
1462 | desc = ext2_get_group_desc (sb, i, NULL); | |
1463 | if (!desc) | |
1464 | continue; | |
1465 | desc_count += le16_to_cpu(desc->bg_free_blocks_count); | |
1466 | bitmap_bh = read_block_bitmap(sb, i); | |
1467 | if (!bitmap_bh) | |
1468 | continue; | |
1469 | ||
1470 | x = ext2_count_free(bitmap_bh, sb->s_blocksize); | |
1471 | printk ("group %d: stored = %d, counted = %lu\n", | |
1472 | i, le16_to_cpu(desc->bg_free_blocks_count), x); | |
1473 | bitmap_count += x; | |
1474 | brelse(bitmap_bh); | |
1475 | } | |
1476 | printk("ext2_count_free_blocks: stored = %lu, computed = %lu, %lu\n", | |
1477 | (long)le32_to_cpu(es->s_free_blocks_count), | |
1478 | desc_count, bitmap_count); | |
1da177e4 LT |
1479 | return bitmap_count; |
1480 | #else | |
1481 | for (i = 0; i < EXT2_SB(sb)->s_groups_count; i++) { | |
1482 | desc = ext2_get_group_desc (sb, i, NULL); | |
1483 | if (!desc) | |
1484 | continue; | |
1485 | desc_count += le16_to_cpu(desc->bg_free_blocks_count); | |
1486 | } | |
1487 | return desc_count; | |
1488 | #endif | |
1489 | } | |
1490 | ||
1da177e4 LT |
1491 | static inline int test_root(int a, int b) |
1492 | { | |
1493 | int num = b; | |
1494 | ||
1495 | while (a > num) | |
1496 | num *= b; | |
1497 | return num == a; | |
1498 | } | |
1499 | ||
1500 | static int ext2_group_sparse(int group) | |
1501 | { | |
1502 | if (group <= 1) | |
1503 | return 1; | |
1504 | return (test_root(group, 3) || test_root(group, 5) || | |
1505 | test_root(group, 7)); | |
1506 | } | |
1507 | ||
1508 | /** | |
1509 | * ext2_bg_has_super - number of blocks used by the superblock in group | |
1510 | * @sb: superblock for filesystem | |
1511 | * @group: group number to check | |
1512 | * | |
1513 | * Return the number of blocks used by the superblock (primary or backup) | |
1514 | * in this group. Currently this will be only 0 or 1. | |
1515 | */ | |
1516 | int ext2_bg_has_super(struct super_block *sb, int group) | |
1517 | { | |
1518 | if (EXT2_HAS_RO_COMPAT_FEATURE(sb,EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER)&& | |
1519 | !ext2_group_sparse(group)) | |
1520 | return 0; | |
1521 | return 1; | |
1522 | } | |
1523 | ||
1524 | /** | |
1525 | * ext2_bg_num_gdb - number of blocks used by the group table in group | |
1526 | * @sb: superblock for filesystem | |
1527 | * @group: group number to check | |
1528 | * | |
1529 | * Return the number of blocks used by the group descriptor table | |
1530 | * (primary or backup) in this group. In the future there may be a | |
1531 | * different number of descriptor blocks in each group. | |
1532 | */ | |
1533 | unsigned long ext2_bg_num_gdb(struct super_block *sb, int group) | |
1534 | { | |
859cb936 | 1535 | return ext2_bg_has_super(sb, group) ? EXT2_SB(sb)->s_gdb_count : 0; |
1da177e4 LT |
1536 | } |
1537 |