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authorDave Kleikamp <shaggy@austin.ibm.com>2006-10-11 04:20:50 -0400
committerLinus Torvalds <torvalds@g5.osdl.org>2006-10-11 14:14:15 -0400
commitac27a0ec112a089f1a5102bc8dffc79c8c815571 (patch)
treebcbcc0a5a88bf99b35119d9d9d660a37c503d787 /fs/ext4/balloc.c
parent502717f4e112b18d9c37753a32f675bec9f2838b (diff)
[PATCH] ext4: initial copy of files from ext3
Start of the ext4 patch series. See Documentation/filesystems/ext4.txt for details. This is a simple copy of the files in fs/ext3 to fs/ext4 and /usr/incude/linux/ext3* to /usr/include/ex4* Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'fs/ext4/balloc.c')
-rw-r--r--fs/ext4/balloc.c1818
1 files changed, 1818 insertions, 0 deletions
diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
new file mode 100644
index 000000000000..b41a7d7e20f0
--- /dev/null
+++ b/fs/ext4/balloc.c
@@ -0,0 +1,1818 @@
1/*
2 * linux/fs/ext3/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
14#include <linux/time.h>
15#include <linux/capability.h>
16#include <linux/fs.h>
17#include <linux/jbd.h>
18#include <linux/ext3_fs.h>
19#include <linux/ext3_jbd.h>
20#include <linux/quotaops.h>
21#include <linux/buffer_head.h>
22
23/*
24 * balloc.c contains the blocks allocation and deallocation routines
25 */
26
27/*
28 * The free blocks are managed by bitmaps. A file system contains several
29 * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap
30 * block for inodes, N blocks for the inode table and data blocks.
31 *
32 * The file system contains group descriptors which are located after the
33 * super block. Each descriptor contains the number of the bitmap block and
34 * the free blocks count in the block. The descriptors are loaded in memory
35 * when a file system is mounted (see ext3_read_super).
36 */
37
38
39#define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1)
40
41/**
42 * ext3_get_group_desc() -- load group descriptor from disk
43 * @sb: super block
44 * @block_group: given block group
45 * @bh: pointer to the buffer head to store the block
46 * group descriptor
47 */
48struct ext3_group_desc * ext3_get_group_desc(struct super_block * sb,
49 unsigned int block_group,
50 struct buffer_head ** bh)
51{
52 unsigned long group_desc;
53 unsigned long offset;
54 struct ext3_group_desc * desc;
55 struct ext3_sb_info *sbi = EXT3_SB(sb);
56
57 if (block_group >= sbi->s_groups_count) {
58 ext3_error (sb, "ext3_get_group_desc",
59 "block_group >= groups_count - "
60 "block_group = %d, groups_count = %lu",
61 block_group, sbi->s_groups_count);
62
63 return NULL;
64 }
65 smp_rmb();
66
67 group_desc = block_group >> EXT3_DESC_PER_BLOCK_BITS(sb);
68 offset = block_group & (EXT3_DESC_PER_BLOCK(sb) - 1);
69 if (!sbi->s_group_desc[group_desc]) {
70 ext3_error (sb, "ext3_get_group_desc",
71 "Group descriptor not loaded - "
72 "block_group = %d, group_desc = %lu, desc = %lu",
73 block_group, group_desc, offset);
74 return NULL;
75 }
76
77 desc = (struct ext3_group_desc *) sbi->s_group_desc[group_desc]->b_data;
78 if (bh)
79 *bh = sbi->s_group_desc[group_desc];
80 return desc + offset;
81}
82
83/**
84 * read_block_bitmap()
85 * @sb: super block
86 * @block_group: given block group
87 *
88 * Read the bitmap for a given block_group, reading into the specified
89 * slot in the superblock's bitmap cache.
90 *
91 * Return buffer_head on success or NULL in case of failure.
92 */
93static struct buffer_head *
94read_block_bitmap(struct super_block *sb, unsigned int block_group)
95{
96 struct ext3_group_desc * desc;
97 struct buffer_head * bh = NULL;
98
99 desc = ext3_get_group_desc (sb, block_group, NULL);
100 if (!desc)
101 goto error_out;
102 bh = sb_bread(sb, le32_to_cpu(desc->bg_block_bitmap));
103 if (!bh)
104 ext3_error (sb, "read_block_bitmap",
105 "Cannot read block bitmap - "
106 "block_group = %d, block_bitmap = %u",
107 block_group, le32_to_cpu(desc->bg_block_bitmap));
108error_out:
109 return bh;
110}
111/*
112 * The reservation window structure operations
113 * --------------------------------------------
114 * Operations include:
115 * dump, find, add, remove, is_empty, find_next_reservable_window, etc.
116 *
117 * We use a red-black tree to represent per-filesystem reservation
118 * windows.
119 *
120 */
121
122/**
123 * __rsv_window_dump() -- Dump the filesystem block allocation reservation map
124 * @rb_root: root of per-filesystem reservation rb tree
125 * @verbose: verbose mode
126 * @fn: function which wishes to dump the reservation map
127 *
128 * If verbose is turned on, it will print the whole block reservation
129 * windows(start, end). Otherwise, it will only print out the "bad" windows,
130 * those windows that overlap with their immediate neighbors.
131 */
132#if 1
133static void __rsv_window_dump(struct rb_root *root, int verbose,
134 const char *fn)
135{
136 struct rb_node *n;
137 struct ext3_reserve_window_node *rsv, *prev;
138 int bad;
139
140restart:
141 n = rb_first(root);
142 bad = 0;
143 prev = NULL;
144
145 printk("Block Allocation Reservation Windows Map (%s):\n", fn);
146 while (n) {
147 rsv = list_entry(n, struct ext3_reserve_window_node, rsv_node);
148 if (verbose)
149 printk("reservation window 0x%p "
150 "start: %lu, end: %lu\n",
151 rsv, rsv->rsv_start, rsv->rsv_end);
152 if (rsv->rsv_start && rsv->rsv_start >= rsv->rsv_end) {
153 printk("Bad reservation %p (start >= end)\n",
154 rsv);
155 bad = 1;
156 }
157 if (prev && prev->rsv_end >= rsv->rsv_start) {
158 printk("Bad reservation %p (prev->end >= start)\n",
159 rsv);
160 bad = 1;
161 }
162 if (bad) {
163 if (!verbose) {
164 printk("Restarting reservation walk in verbose mode\n");
165 verbose = 1;
166 goto restart;
167 }
168 }
169 n = rb_next(n);
170 prev = rsv;
171 }
172 printk("Window map complete.\n");
173 if (bad)
174 BUG();
175}
176#define rsv_window_dump(root, verbose) \
177 __rsv_window_dump((root), (verbose), __FUNCTION__)
178#else
179#define rsv_window_dump(root, verbose) do {} while (0)
180#endif
181
182/**
183 * goal_in_my_reservation()
184 * @rsv: inode's reservation window
185 * @grp_goal: given goal block relative to the allocation block group
186 * @group: the current allocation block group
187 * @sb: filesystem super block
188 *
189 * Test if the given goal block (group relative) is within the file's
190 * own block reservation window range.
191 *
192 * If the reservation window is outside the goal allocation group, return 0;
193 * grp_goal (given goal block) could be -1, which means no specific
194 * goal block. In this case, always return 1.
195 * If the goal block is within the reservation window, return 1;
196 * otherwise, return 0;
197 */
198static int
199goal_in_my_reservation(struct ext3_reserve_window *rsv, ext3_grpblk_t grp_goal,
200 unsigned int group, struct super_block * sb)
201{
202 ext3_fsblk_t group_first_block, group_last_block;
203
204 group_first_block = ext3_group_first_block_no(sb, group);
205 group_last_block = group_first_block + (EXT3_BLOCKS_PER_GROUP(sb) - 1);
206
207 if ((rsv->_rsv_start > group_last_block) ||
208 (rsv->_rsv_end < group_first_block))
209 return 0;
210 if ((grp_goal >= 0) && ((grp_goal + group_first_block < rsv->_rsv_start)
211 || (grp_goal + group_first_block > rsv->_rsv_end)))
212 return 0;
213 return 1;
214}
215
216/**
217 * search_reserve_window()
218 * @rb_root: root of reservation tree
219 * @goal: target allocation block
220 *
221 * Find the reserved window which includes the goal, or the previous one
222 * if the goal is not in any window.
223 * Returns NULL if there are no windows or if all windows start after the goal.
224 */
225static struct ext3_reserve_window_node *
226search_reserve_window(struct rb_root *root, ext3_fsblk_t goal)
227{
228 struct rb_node *n = root->rb_node;
229 struct ext3_reserve_window_node *rsv;
230
231 if (!n)
232 return NULL;
233
234 do {
235 rsv = rb_entry(n, struct ext3_reserve_window_node, rsv_node);
236
237 if (goal < rsv->rsv_start)
238 n = n->rb_left;
239 else if (goal > rsv->rsv_end)
240 n = n->rb_right;
241 else
242 return rsv;
243 } while (n);
244 /*
245 * We've fallen off the end of the tree: the goal wasn't inside
246 * any particular node. OK, the previous node must be to one
247 * side of the interval containing the goal. If it's the RHS,
248 * we need to back up one.
249 */
250 if (rsv->rsv_start > goal) {
251 n = rb_prev(&rsv->rsv_node);
252 rsv = rb_entry(n, struct ext3_reserve_window_node, rsv_node);
253 }
254 return rsv;
255}
256
257/**
258 * ext3_rsv_window_add() -- Insert a window to the block reservation rb tree.
259 * @sb: super block
260 * @rsv: reservation window to add
261 *
262 * Must be called with rsv_lock hold.
263 */
264void ext3_rsv_window_add(struct super_block *sb,
265 struct ext3_reserve_window_node *rsv)
266{
267 struct rb_root *root = &EXT3_SB(sb)->s_rsv_window_root;
268 struct rb_node *node = &rsv->rsv_node;
269 ext3_fsblk_t start = rsv->rsv_start;
270
271 struct rb_node ** p = &root->rb_node;
272 struct rb_node * parent = NULL;
273 struct ext3_reserve_window_node *this;
274
275 while (*p)
276 {
277 parent = *p;
278 this = rb_entry(parent, struct ext3_reserve_window_node, rsv_node);
279
280 if (start < this->rsv_start)
281 p = &(*p)->rb_left;
282 else if (start > this->rsv_end)
283 p = &(*p)->rb_right;
284 else {
285 rsv_window_dump(root, 1);
286 BUG();
287 }
288 }
289
290 rb_link_node(node, parent, p);
291 rb_insert_color(node, root);
292}
293
294/**
295 * ext3_rsv_window_remove() -- unlink a window from the reservation rb tree
296 * @sb: super block
297 * @rsv: reservation window to remove
298 *
299 * Mark the block reservation window as not allocated, and unlink it
300 * from the filesystem reservation window rb tree. Must be called with
301 * rsv_lock hold.
302 */
303static void rsv_window_remove(struct super_block *sb,
304 struct ext3_reserve_window_node *rsv)
305{
306 rsv->rsv_start = EXT3_RESERVE_WINDOW_NOT_ALLOCATED;
307 rsv->rsv_end = EXT3_RESERVE_WINDOW_NOT_ALLOCATED;
308 rsv->rsv_alloc_hit = 0;
309 rb_erase(&rsv->rsv_node, &EXT3_SB(sb)->s_rsv_window_root);
310}
311
312/*
313 * rsv_is_empty() -- Check if the reservation window is allocated.
314 * @rsv: given reservation window to check
315 *
316 * returns 1 if the end block is EXT3_RESERVE_WINDOW_NOT_ALLOCATED.
317 */
318static inline int rsv_is_empty(struct ext3_reserve_window *rsv)
319{
320 /* a valid reservation end block could not be 0 */
321 return rsv->_rsv_end == EXT3_RESERVE_WINDOW_NOT_ALLOCATED;
322}
323
324/**
325 * ext3_init_block_alloc_info()
326 * @inode: file inode structure
327 *
328 * Allocate and initialize the reservation window structure, and
329 * link the window to the ext3 inode structure at last
330 *
331 * The reservation window structure is only dynamically allocated
332 * and linked to ext3 inode the first time the open file
333 * needs a new block. So, before every ext3_new_block(s) call, for
334 * regular files, we should check whether the reservation window
335 * structure exists or not. In the latter case, this function is called.
336 * Fail to do so will result in block reservation being turned off for that
337 * open file.
338 *
339 * This function is called from ext3_get_blocks_handle(), also called
340 * when setting the reservation window size through ioctl before the file
341 * is open for write (needs block allocation).
342 *
343 * Needs truncate_mutex protection prior to call this function.
344 */
345void ext3_init_block_alloc_info(struct inode *inode)
346{
347 struct ext3_inode_info *ei = EXT3_I(inode);
348 struct ext3_block_alloc_info *block_i = ei->i_block_alloc_info;
349 struct super_block *sb = inode->i_sb;
350
351 block_i = kmalloc(sizeof(*block_i), GFP_NOFS);
352 if (block_i) {
353 struct ext3_reserve_window_node *rsv = &block_i->rsv_window_node;
354
355 rsv->rsv_start = EXT3_RESERVE_WINDOW_NOT_ALLOCATED;
356 rsv->rsv_end = EXT3_RESERVE_WINDOW_NOT_ALLOCATED;
357
358 /*
359 * if filesystem is mounted with NORESERVATION, the goal
360 * reservation window size is set to zero to indicate
361 * block reservation is off
362 */
363 if (!test_opt(sb, RESERVATION))
364 rsv->rsv_goal_size = 0;
365 else
366 rsv->rsv_goal_size = EXT3_DEFAULT_RESERVE_BLOCKS;
367 rsv->rsv_alloc_hit = 0;
368 block_i->last_alloc_logical_block = 0;
369 block_i->last_alloc_physical_block = 0;
370 }
371 ei->i_block_alloc_info = block_i;
372}
373
374/**
375 * ext3_discard_reservation()
376 * @inode: inode
377 *
378 * Discard(free) block reservation window on last file close, or truncate
379 * or at last iput().
380 *
381 * It is being called in three cases:
382 * ext3_release_file(): last writer close the file
383 * ext3_clear_inode(): last iput(), when nobody link to this file.
384 * ext3_truncate(): when the block indirect map is about to change.
385 *
386 */
387void ext3_discard_reservation(struct inode *inode)
388{
389 struct ext3_inode_info *ei = EXT3_I(inode);
390 struct ext3_block_alloc_info *block_i = ei->i_block_alloc_info;
391 struct ext3_reserve_window_node *rsv;
392 spinlock_t *rsv_lock = &EXT3_SB(inode->i_sb)->s_rsv_window_lock;
393
394 if (!block_i)
395 return;
396
397 rsv = &block_i->rsv_window_node;
398 if (!rsv_is_empty(&rsv->rsv_window)) {
399 spin_lock(rsv_lock);
400 if (!rsv_is_empty(&rsv->rsv_window))
401 rsv_window_remove(inode->i_sb, rsv);
402 spin_unlock(rsv_lock);
403 }
404}
405
406/**
407 * ext3_free_blocks_sb() -- Free given blocks and update quota
408 * @handle: handle to this transaction
409 * @sb: super block
410 * @block: start physcial block to free
411 * @count: number of blocks to free
412 * @pdquot_freed_blocks: pointer to quota
413 */
414void ext3_free_blocks_sb(handle_t *handle, struct super_block *sb,
415 ext3_fsblk_t block, unsigned long count,
416 unsigned long *pdquot_freed_blocks)
417{
418 struct buffer_head *bitmap_bh = NULL;
419 struct buffer_head *gd_bh;
420 unsigned long block_group;
421 ext3_grpblk_t bit;
422 unsigned long i;
423 unsigned long overflow;
424 struct ext3_group_desc * desc;
425 struct ext3_super_block * es;
426 struct ext3_sb_info *sbi;
427 int err = 0, ret;
428 ext3_grpblk_t group_freed;
429
430 *pdquot_freed_blocks = 0;
431 sbi = EXT3_SB(sb);
432 es = sbi->s_es;
433 if (block < le32_to_cpu(es->s_first_data_block) ||
434 block + count < block ||
435 block + count > le32_to_cpu(es->s_blocks_count)) {
436 ext3_error (sb, "ext3_free_blocks",
437 "Freeing blocks not in datazone - "
438 "block = "E3FSBLK", count = %lu", block, count);
439 goto error_return;
440 }
441
442 ext3_debug ("freeing block(s) %lu-%lu\n", block, block + count - 1);
443
444do_more:
445 overflow = 0;
446 block_group = (block - le32_to_cpu(es->s_first_data_block)) /
447 EXT3_BLOCKS_PER_GROUP(sb);
448 bit = (block - le32_to_cpu(es->s_first_data_block)) %
449 EXT3_BLOCKS_PER_GROUP(sb);
450 /*
451 * Check to see if we are freeing blocks across a group
452 * boundary.
453 */
454 if (bit + count > EXT3_BLOCKS_PER_GROUP(sb)) {
455 overflow = bit + count - EXT3_BLOCKS_PER_GROUP(sb);
456 count -= overflow;
457 }
458 brelse(bitmap_bh);
459 bitmap_bh = read_block_bitmap(sb, block_group);
460 if (!bitmap_bh)
461 goto error_return;
462 desc = ext3_get_group_desc (sb, block_group, &gd_bh);
463 if (!desc)
464 goto error_return;
465
466 if (in_range (le32_to_cpu(desc->bg_block_bitmap), block, count) ||
467 in_range (le32_to_cpu(desc->bg_inode_bitmap), block, count) ||
468 in_range (block, le32_to_cpu(desc->bg_inode_table),
469 sbi->s_itb_per_group) ||
470 in_range (block + count - 1, le32_to_cpu(desc->bg_inode_table),
471 sbi->s_itb_per_group))
472 ext3_error (sb, "ext3_free_blocks",
473 "Freeing blocks in system zones - "
474 "Block = "E3FSBLK", count = %lu",
475 block, count);
476
477 /*
478 * We are about to start releasing blocks in the bitmap,
479 * so we need undo access.
480 */
481 /* @@@ check errors */
482 BUFFER_TRACE(bitmap_bh, "getting undo access");
483 err = ext3_journal_get_undo_access(handle, bitmap_bh);
484 if (err)
485 goto error_return;
486
487 /*
488 * We are about to modify some metadata. Call the journal APIs
489 * to unshare ->b_data if a currently-committing transaction is
490 * using it
491 */
492 BUFFER_TRACE(gd_bh, "get_write_access");
493 err = ext3_journal_get_write_access(handle, gd_bh);
494 if (err)
495 goto error_return;
496
497 jbd_lock_bh_state(bitmap_bh);
498
499 for (i = 0, group_freed = 0; i < count; i++) {
500 /*
501 * An HJ special. This is expensive...
502 */
503#ifdef CONFIG_JBD_DEBUG
504 jbd_unlock_bh_state(bitmap_bh);
505 {
506 struct buffer_head *debug_bh;
507 debug_bh = sb_find_get_block(sb, block + i);
508 if (debug_bh) {
509 BUFFER_TRACE(debug_bh, "Deleted!");
510 if (!bh2jh(bitmap_bh)->b_committed_data)
511 BUFFER_TRACE(debug_bh,
512 "No commited data in bitmap");
513 BUFFER_TRACE2(debug_bh, bitmap_bh, "bitmap");
514 __brelse(debug_bh);
515 }
516 }
517 jbd_lock_bh_state(bitmap_bh);
518#endif
519 if (need_resched()) {
520 jbd_unlock_bh_state(bitmap_bh);
521 cond_resched();
522 jbd_lock_bh_state(bitmap_bh);
523 }
524 /* @@@ This prevents newly-allocated data from being
525 * freed and then reallocated within the same
526 * transaction.
527 *
528 * Ideally we would want to allow that to happen, but to
529 * do so requires making journal_forget() capable of
530 * revoking the queued write of a data block, which
531 * implies blocking on the journal lock. *forget()
532 * cannot block due to truncate races.
533 *
534 * Eventually we can fix this by making journal_forget()
535 * return a status indicating whether or not it was able
536 * to revoke the buffer. On successful revoke, it is
537 * safe not to set the allocation bit in the committed
538 * bitmap, because we know that there is no outstanding
539 * activity on the buffer any more and so it is safe to
540 * reallocate it.
541 */
542 BUFFER_TRACE(bitmap_bh, "set in b_committed_data");
543 J_ASSERT_BH(bitmap_bh,
544 bh2jh(bitmap_bh)->b_committed_data != NULL);
545 ext3_set_bit_atomic(sb_bgl_lock(sbi, block_group), bit + i,
546 bh2jh(bitmap_bh)->b_committed_data);
547
548 /*
549 * We clear the bit in the bitmap after setting the committed
550 * data bit, because this is the reverse order to that which
551 * the allocator uses.
552 */
553 BUFFER_TRACE(bitmap_bh, "clear bit");
554 if (!ext3_clear_bit_atomic(sb_bgl_lock(sbi, block_group),
555 bit + i, bitmap_bh->b_data)) {
556 jbd_unlock_bh_state(bitmap_bh);
557 ext3_error(sb, __FUNCTION__,
558 "bit already cleared for block "E3FSBLK,
559 block + i);
560 jbd_lock_bh_state(bitmap_bh);
561 BUFFER_TRACE(bitmap_bh, "bit already cleared");
562 } else {
563 group_freed++;
564 }
565 }
566 jbd_unlock_bh_state(bitmap_bh);
567
568 spin_lock(sb_bgl_lock(sbi, block_group));
569 desc->bg_free_blocks_count =
570 cpu_to_le16(le16_to_cpu(desc->bg_free_blocks_count) +
571 group_freed);
572 spin_unlock(sb_bgl_lock(sbi, block_group));
573 percpu_counter_mod(&sbi->s_freeblocks_counter, count);
574
575 /* We dirtied the bitmap block */
576 BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
577 err = ext3_journal_dirty_metadata(handle, bitmap_bh);
578
579 /* And the group descriptor block */
580 BUFFER_TRACE(gd_bh, "dirtied group descriptor block");
581 ret = ext3_journal_dirty_metadata(handle, gd_bh);
582 if (!err) err = ret;
583 *pdquot_freed_blocks += group_freed;
584
585 if (overflow && !err) {
586 block += count;
587 count = overflow;
588 goto do_more;
589 }
590 sb->s_dirt = 1;
591error_return:
592 brelse(bitmap_bh);
593 ext3_std_error(sb, err);
594 return;
595}
596
597/**
598 * ext3_free_blocks() -- Free given blocks and update quota
599 * @handle: handle for this transaction
600 * @inode: inode
601 * @block: start physical block to free
602 * @count: number of blocks to count
603 */
604void ext3_free_blocks(handle_t *handle, struct inode *inode,
605 ext3_fsblk_t block, unsigned long count)
606{
607 struct super_block * sb;
608 unsigned long dquot_freed_blocks;
609
610 sb = inode->i_sb;
611 if (!sb) {
612 printk ("ext3_free_blocks: nonexistent device");
613 return;
614 }
615 ext3_free_blocks_sb(handle, sb, block, count, &dquot_freed_blocks);
616 if (dquot_freed_blocks)
617 DQUOT_FREE_BLOCK(inode, dquot_freed_blocks);
618 return;
619}
620
621/**
622 * ext3_test_allocatable()
623 * @nr: given allocation block group
624 * @bh: bufferhead contains the bitmap of the given block group
625 *
626 * For ext3 allocations, we must not reuse any blocks which are
627 * allocated in the bitmap buffer's "last committed data" copy. This
628 * prevents deletes from freeing up the page for reuse until we have
629 * committed the delete transaction.
630 *
631 * If we didn't do this, then deleting something and reallocating it as
632 * data would allow the old block to be overwritten before the
633 * transaction committed (because we force data to disk before commit).
634 * This would lead to corruption if we crashed between overwriting the
635 * data and committing the delete.
636 *
637 * @@@ We may want to make this allocation behaviour conditional on
638 * data-writes at some point, and disable it for metadata allocations or
639 * sync-data inodes.
640 */
641static int ext3_test_allocatable(ext3_grpblk_t nr, struct buffer_head *bh)
642{
643 int ret;
644 struct journal_head *jh = bh2jh(bh);
645
646 if (ext3_test_bit(nr, bh->b_data))
647 return 0;
648
649 jbd_lock_bh_state(bh);
650 if (!jh->b_committed_data)
651 ret = 1;
652 else
653 ret = !ext3_test_bit(nr, jh->b_committed_data);
654 jbd_unlock_bh_state(bh);
655 return ret;
656}
657
658/**
659 * bitmap_search_next_usable_block()
660 * @start: the starting block (group relative) of the search
661 * @bh: bufferhead contains the block group bitmap
662 * @maxblocks: the ending block (group relative) of the reservation
663 *
664 * The bitmap search --- search forward alternately through the actual
665 * bitmap on disk and the last-committed copy in journal, until we find a
666 * bit free in both bitmaps.
667 */
668static ext3_grpblk_t
669bitmap_search_next_usable_block(ext3_grpblk_t start, struct buffer_head *bh,
670 ext3_grpblk_t maxblocks)
671{
672 ext3_grpblk_t next;
673 struct journal_head *jh = bh2jh(bh);
674
675 while (start < maxblocks) {
676 next = ext3_find_next_zero_bit(bh->b_data, maxblocks, start);
677 if (next >= maxblocks)
678 return -1;
679 if (ext3_test_allocatable(next, bh))
680 return next;
681 jbd_lock_bh_state(bh);
682 if (jh->b_committed_data)
683 start = ext3_find_next_zero_bit(jh->b_committed_data,
684 maxblocks, next);
685 jbd_unlock_bh_state(bh);
686 }
687 return -1;
688}
689
690/**
691 * find_next_usable_block()
692 * @start: the starting block (group relative) to find next
693 * allocatable block in bitmap.
694 * @bh: bufferhead contains the block group bitmap
695 * @maxblocks: the ending block (group relative) for the search
696 *
697 * Find an allocatable block in a bitmap. We honor both the bitmap and
698 * its last-committed copy (if that exists), and perform the "most
699 * appropriate allocation" algorithm of looking for a free block near
700 * the initial goal; then for a free byte somewhere in the bitmap; then
701 * for any free bit in the bitmap.
702 */
703static ext3_grpblk_t
704find_next_usable_block(ext3_grpblk_t start, struct buffer_head *bh,
705 ext3_grpblk_t maxblocks)
706{
707 ext3_grpblk_t here, next;
708 char *p, *r;
709
710 if (start > 0) {
711 /*
712 * The goal was occupied; search forward for a free
713 * block within the next XX blocks.
714 *
715 * end_goal is more or less random, but it has to be
716 * less than EXT3_BLOCKS_PER_GROUP. Aligning up to the
717 * next 64-bit boundary is simple..
718 */
719 ext3_grpblk_t end_goal = (start + 63) & ~63;
720 if (end_goal > maxblocks)
721 end_goal = maxblocks;
722 here = ext3_find_next_zero_bit(bh->b_data, end_goal, start);
723 if (here < end_goal && ext3_test_allocatable(here, bh))
724 return here;
725 ext3_debug("Bit not found near goal\n");
726 }
727
728 here = start;
729 if (here < 0)
730 here = 0;
731
732 p = ((char *)bh->b_data) + (here >> 3);
733 r = memscan(p, 0, (maxblocks - here + 7) >> 3);
734 next = (r - ((char *)bh->b_data)) << 3;
735
736 if (next < maxblocks && next >= start && ext3_test_allocatable(next, bh))
737 return next;
738
739 /*
740 * The bitmap search --- search forward alternately through the actual
741 * bitmap and the last-committed copy until we find a bit free in
742 * both
743 */
744 here = bitmap_search_next_usable_block(here, bh, maxblocks);
745 return here;
746}
747
748/**
749 * claim_block()
750 * @block: the free block (group relative) to allocate
751 * @bh: the bufferhead containts the block group bitmap
752 *
753 * We think we can allocate this block in this bitmap. Try to set the bit.
754 * If that succeeds then check that nobody has allocated and then freed the
755 * block since we saw that is was not marked in b_committed_data. If it _was_
756 * allocated and freed then clear the bit in the bitmap again and return
757 * zero (failure).
758 */
759static inline int
760claim_block(spinlock_t *lock, ext3_grpblk_t block, struct buffer_head *bh)
761{
762 struct journal_head *jh = bh2jh(bh);
763 int ret;
764
765 if (ext3_set_bit_atomic(lock, block, bh->b_data))
766 return 0;
767 jbd_lock_bh_state(bh);
768 if (jh->b_committed_data && ext3_test_bit(block,jh->b_committed_data)) {
769 ext3_clear_bit_atomic(lock, block, bh->b_data);
770 ret = 0;
771 } else {
772 ret = 1;
773 }
774 jbd_unlock_bh_state(bh);
775 return ret;
776}
777
778/**
779 * ext3_try_to_allocate()
780 * @sb: superblock
781 * @handle: handle to this transaction
782 * @group: given allocation block group
783 * @bitmap_bh: bufferhead holds the block bitmap
784 * @grp_goal: given target block within the group
785 * @count: target number of blocks to allocate
786 * @my_rsv: reservation window
787 *
788 * Attempt to allocate blocks within a give range. Set the range of allocation
789 * first, then find the first free bit(s) from the bitmap (within the range),
790 * and at last, allocate the blocks by claiming the found free bit as allocated.
791 *
792 * To set the range of this allocation:
793 * if there is a reservation window, only try to allocate block(s) from the
794 * file's own reservation window;
795 * Otherwise, the allocation range starts from the give goal block, ends at
796 * the block group's last block.
797 *
798 * If we failed to allocate the desired block then we may end up crossing to a
799 * new bitmap. In that case we must release write access to the old one via
800 * ext3_journal_release_buffer(), else we'll run out of credits.
801 */
802static ext3_grpblk_t
803ext3_try_to_allocate(struct super_block *sb, handle_t *handle, int group,
804 struct buffer_head *bitmap_bh, ext3_grpblk_t grp_goal,
805 unsigned long *count, struct ext3_reserve_window *my_rsv)
806{
807 ext3_fsblk_t group_first_block;
808 ext3_grpblk_t start, end;
809 unsigned long num = 0;
810
811 /* we do allocation within the reservation window if we have a window */
812 if (my_rsv) {
813 group_first_block = ext3_group_first_block_no(sb, group);
814 if (my_rsv->_rsv_start >= group_first_block)
815 start = my_rsv->_rsv_start - group_first_block;
816 else
817 /* reservation window cross group boundary */
818 start = 0;
819 end = my_rsv->_rsv_end - group_first_block + 1;
820 if (end > EXT3_BLOCKS_PER_GROUP(sb))
821 /* reservation window crosses group boundary */
822 end = EXT3_BLOCKS_PER_GROUP(sb);
823 if ((start <= grp_goal) && (grp_goal < end))
824 start = grp_goal;
825 else
826 grp_goal = -1;
827 } else {
828 if (grp_goal > 0)
829 start = grp_goal;
830 else
831 start = 0;
832 end = EXT3_BLOCKS_PER_GROUP(sb);
833 }
834
835 BUG_ON(start > EXT3_BLOCKS_PER_GROUP(sb));
836
837repeat:
838 if (grp_goal < 0 || !ext3_test_allocatable(grp_goal, bitmap_bh)) {
839 grp_goal = find_next_usable_block(start, bitmap_bh, end);
840 if (grp_goal < 0)
841 goto fail_access;
842 if (!my_rsv) {
843 int i;
844
845 for (i = 0; i < 7 && grp_goal > start &&
846 ext3_test_allocatable(grp_goal - 1,
847 bitmap_bh);
848 i++, grp_goal--)
849 ;
850 }
851 }
852 start = grp_goal;
853
854 if (!claim_block(sb_bgl_lock(EXT3_SB(sb), group),
855 grp_goal, bitmap_bh)) {
856 /*
857 * The block was allocated by another thread, or it was
858 * allocated and then freed by another thread
859 */
860 start++;
861 grp_goal++;
862 if (start >= end)
863 goto fail_access;
864 goto repeat;
865 }
866 num++;
867 grp_goal++;
868 while (num < *count && grp_goal < end
869 && ext3_test_allocatable(grp_goal, bitmap_bh)
870 && claim_block(sb_bgl_lock(EXT3_SB(sb), group),
871 grp_goal, bitmap_bh)) {
872 num++;
873 grp_goal++;
874 }
875 *count = num;
876 return grp_goal - num;
877fail_access:
878 *count = num;
879 return -1;
880}
881
882/**
883 * find_next_reservable_window():
884 * find a reservable space within the given range.
885 * It does not allocate the reservation window for now:
886 * alloc_new_reservation() will do the work later.
887 *
888 * @search_head: the head of the searching list;
889 * This is not necessarily the list head of the whole filesystem
890 *
891 * We have both head and start_block to assist the search
892 * for the reservable space. The list starts from head,
893 * but we will shift to the place where start_block is,
894 * then start from there, when looking for a reservable space.
895 *
896 * @size: the target new reservation window size
897 *
898 * @group_first_block: the first block we consider to start
899 * the real search from
900 *
901 * @last_block:
902 * the maximum block number that our goal reservable space
903 * could start from. This is normally the last block in this
904 * group. The search will end when we found the start of next
905 * possible reservable space is out of this boundary.
906 * This could handle the cross boundary reservation window
907 * request.
908 *
909 * basically we search from the given range, rather than the whole
910 * reservation double linked list, (start_block, last_block)
911 * to find a free region that is of my size and has not
912 * been reserved.
913 *
914 */
915static int find_next_reservable_window(
916 struct ext3_reserve_window_node *search_head,
917 struct ext3_reserve_window_node *my_rsv,
918 struct super_block * sb,
919 ext3_fsblk_t start_block,
920 ext3_fsblk_t last_block)
921{
922 struct rb_node *next;
923 struct ext3_reserve_window_node *rsv, *prev;
924 ext3_fsblk_t cur;
925 int size = my_rsv->rsv_goal_size;
926
927 /* TODO: make the start of the reservation window byte-aligned */
928 /* cur = *start_block & ~7;*/
929 cur = start_block;
930 rsv = search_head;
931 if (!rsv)
932 return -1;
933
934 while (1) {
935 if (cur <= rsv->rsv_end)
936 cur = rsv->rsv_end + 1;
937
938 /* TODO?
939 * in the case we could not find a reservable space
940 * that is what is expected, during the re-search, we could
941 * remember what's the largest reservable space we could have
942 * and return that one.
943 *
944 * For now it will fail if we could not find the reservable
945 * space with expected-size (or more)...
946 */
947 if (cur > last_block)
948 return -1; /* fail */
949
950 prev = rsv;
951 next = rb_next(&rsv->rsv_node);
952 rsv = list_entry(next,struct ext3_reserve_window_node,rsv_node);
953
954 /*
955 * Reached the last reservation, we can just append to the
956 * previous one.
957 */
958 if (!next)
959 break;
960
961 if (cur + size <= rsv->rsv_start) {
962 /*
963 * Found a reserveable space big enough. We could
964 * have a reservation across the group boundary here
965 */
966 break;
967 }
968 }
969 /*
970 * we come here either :
971 * when we reach the end of the whole list,
972 * and there is empty reservable space after last entry in the list.
973 * append it to the end of the list.
974 *
975 * or we found one reservable space in the middle of the list,
976 * return the reservation window that we could append to.
977 * succeed.
978 */
979
980 if ((prev != my_rsv) && (!rsv_is_empty(&my_rsv->rsv_window)))
981 rsv_window_remove(sb, my_rsv);
982
983 /*
984 * Let's book the whole avaliable window for now. We will check the
985 * disk bitmap later and then, if there are free blocks then we adjust
986 * the window size if it's larger than requested.
987 * Otherwise, we will remove this node from the tree next time
988 * call find_next_reservable_window.
989 */
990 my_rsv->rsv_start = cur;
991 my_rsv->rsv_end = cur + size - 1;
992 my_rsv->rsv_alloc_hit = 0;
993
994 if (prev != my_rsv)
995 ext3_rsv_window_add(sb, my_rsv);
996
997 return 0;
998}
999
1000/**
1001 * alloc_new_reservation()--allocate a new reservation window
1002 *
1003 * To make a new reservation, we search part of the filesystem
1004 * reservation list (the list that inside the group). We try to
1005 * allocate a new reservation window near the allocation goal,
1006 * or the beginning of the group, if there is no goal.
1007 *
1008 * We first find a reservable space after the goal, then from
1009 * there, we check the bitmap for the first free block after
1010 * it. If there is no free block until the end of group, then the
1011 * whole group is full, we failed. Otherwise, check if the free
1012 * block is inside the expected reservable space, if so, we
1013 * succeed.
1014 * If the first free block is outside the reservable space, then
1015 * start from the first free block, we search for next available
1016 * space, and go on.
1017 *
1018 * on succeed, a new reservation will be found and inserted into the list
1019 * It contains at least one free block, and it does not overlap with other
1020 * reservation windows.
1021 *
1022 * failed: we failed to find a reservation window in this group
1023 *
1024 * @rsv: the reservation
1025 *
1026 * @grp_goal: The goal (group-relative). It is where the search for a
1027 * free reservable space should start from.
1028 * if we have a grp_goal(grp_goal >0 ), then start from there,
1029 * no grp_goal(grp_goal = -1), we start from the first block
1030 * of the group.
1031 *
1032 * @sb: the super block
1033 * @group: the group we are trying to allocate in
1034 * @bitmap_bh: the block group block bitmap
1035 *
1036 */
1037static int alloc_new_reservation(struct ext3_reserve_window_node *my_rsv,
1038 ext3_grpblk_t grp_goal, struct super_block *sb,
1039 unsigned int group, struct buffer_head *bitmap_bh)
1040{
1041 struct ext3_reserve_window_node *search_head;
1042 ext3_fsblk_t group_first_block, group_end_block, start_block;
1043 ext3_grpblk_t first_free_block;
1044 struct rb_root *fs_rsv_root = &EXT3_SB(sb)->s_rsv_window_root;
1045 unsigned long size;
1046 int ret;
1047 spinlock_t *rsv_lock = &EXT3_SB(sb)->s_rsv_window_lock;
1048
1049 group_first_block = ext3_group_first_block_no(sb, group);
1050 group_end_block = group_first_block + (EXT3_BLOCKS_PER_GROUP(sb) - 1);
1051
1052 if (grp_goal < 0)
1053 start_block = group_first_block;
1054 else
1055 start_block = grp_goal + group_first_block;
1056
1057 size = my_rsv->rsv_goal_size;
1058
1059 if (!rsv_is_empty(&my_rsv->rsv_window)) {
1060 /*
1061 * if the old reservation is cross group boundary
1062 * and if the goal is inside the old reservation window,
1063 * we will come here when we just failed to allocate from
1064 * the first part of the window. We still have another part
1065 * that belongs to the next group. In this case, there is no
1066 * point to discard our window and try to allocate a new one
1067 * in this group(which will fail). we should
1068 * keep the reservation window, just simply move on.
1069 *
1070 * Maybe we could shift the start block of the reservation
1071 * window to the first block of next group.
1072 */
1073
1074 if ((my_rsv->rsv_start <= group_end_block) &&
1075 (my_rsv->rsv_end > group_end_block) &&
1076 (start_block >= my_rsv->rsv_start))
1077 return -1;
1078
1079 if ((my_rsv->rsv_alloc_hit >
1080 (my_rsv->rsv_end - my_rsv->rsv_start + 1) / 2)) {
1081 /*
1082 * if the previously allocation hit ratio is
1083 * greater than 1/2, then we double the size of
1084 * the reservation window the next time,
1085 * otherwise we keep the same size window
1086 */
1087 size = size * 2;
1088 if (size > EXT3_MAX_RESERVE_BLOCKS)
1089 size = EXT3_MAX_RESERVE_BLOCKS;
1090 my_rsv->rsv_goal_size= size;
1091 }
1092 }
1093
1094 spin_lock(rsv_lock);
1095 /*
1096 * shift the search start to the window near the goal block
1097 */
1098 search_head = search_reserve_window(fs_rsv_root, start_block);
1099
1100 /*
1101 * find_next_reservable_window() simply finds a reservable window
1102 * inside the given range(start_block, group_end_block).
1103 *
1104 * To make sure the reservation window has a free bit inside it, we
1105 * need to check the bitmap after we found a reservable window.
1106 */
1107retry:
1108 ret = find_next_reservable_window(search_head, my_rsv, sb,
1109 start_block, group_end_block);
1110
1111 if (ret == -1) {
1112 if (!rsv_is_empty(&my_rsv->rsv_window))
1113 rsv_window_remove(sb, my_rsv);
1114 spin_unlock(rsv_lock);
1115 return -1;
1116 }
1117
1118 /*
1119 * On success, find_next_reservable_window() returns the
1120 * reservation window where there is a reservable space after it.
1121 * Before we reserve this reservable space, we need
1122 * to make sure there is at least a free block inside this region.
1123 *
1124 * searching the first free bit on the block bitmap and copy of
1125 * last committed bitmap alternatively, until we found a allocatable
1126 * block. Search start from the start block of the reservable space
1127 * we just found.
1128 */
1129 spin_unlock(rsv_lock);
1130 first_free_block = bitmap_search_next_usable_block(
1131 my_rsv->rsv_start - group_first_block,
1132 bitmap_bh, group_end_block - group_first_block + 1);
1133
1134 if (first_free_block < 0) {
1135 /*
1136 * no free block left on the bitmap, no point
1137 * to reserve the space. return failed.
1138 */
1139 spin_lock(rsv_lock);
1140 if (!rsv_is_empty(&my_rsv->rsv_window))
1141 rsv_window_remove(sb, my_rsv);
1142 spin_unlock(rsv_lock);
1143 return -1; /* failed */
1144 }
1145
1146 start_block = first_free_block + group_first_block;
1147 /*
1148 * check if the first free block is within the
1149 * free space we just reserved
1150 */
1151 if (start_block >= my_rsv->rsv_start && start_block < my_rsv->rsv_end)
1152 return 0; /* success */
1153 /*
1154 * if the first free bit we found is out of the reservable space
1155 * continue search for next reservable space,
1156 * start from where the free block is,
1157 * we also shift the list head to where we stopped last time
1158 */
1159 search_head = my_rsv;
1160 spin_lock(rsv_lock);
1161 goto retry;
1162}
1163
1164/**
1165 * try_to_extend_reservation()
1166 * @my_rsv: given reservation window
1167 * @sb: super block
1168 * @size: the delta to extend
1169 *
1170 * Attempt to expand the reservation window large enough to have
1171 * required number of free blocks
1172 *
1173 * Since ext3_try_to_allocate() will always allocate blocks within
1174 * the reservation window range, if the window size is too small,
1175 * multiple blocks allocation has to stop at the end of the reservation
1176 * window. To make this more efficient, given the total number of
1177 * blocks needed and the current size of the window, we try to
1178 * expand the reservation window size if necessary on a best-effort
1179 * basis before ext3_new_blocks() tries to allocate blocks,
1180 */
1181static void try_to_extend_reservation(struct ext3_reserve_window_node *my_rsv,
1182 struct super_block *sb, int size)
1183{
1184 struct ext3_reserve_window_node *next_rsv;
1185 struct rb_node *next;
1186 spinlock_t *rsv_lock = &EXT3_SB(sb)->s_rsv_window_lock;
1187
1188 if (!spin_trylock(rsv_lock))
1189 return;
1190
1191 next = rb_next(&my_rsv->rsv_node);
1192
1193 if (!next)
1194 my_rsv->rsv_end += size;
1195 else {
1196 next_rsv = list_entry(next, struct ext3_reserve_window_node, rsv_node);
1197
1198 if ((next_rsv->rsv_start - my_rsv->rsv_end - 1) >= size)
1199 my_rsv->rsv_end += size;
1200 else
1201 my_rsv->rsv_end = next_rsv->rsv_start - 1;
1202 }
1203 spin_unlock(rsv_lock);
1204}
1205
1206/**
1207 * ext3_try_to_allocate_with_rsv()
1208 * @sb: superblock
1209 * @handle: handle to this transaction
1210 * @group: given allocation block group
1211 * @bitmap_bh: bufferhead holds the block bitmap
1212 * @grp_goal: given target block within the group
1213 * @count: target number of blocks to allocate
1214 * @my_rsv: reservation window
1215 * @errp: pointer to store the error code
1216 *
1217 * This is the main function used to allocate a new block and its reservation
1218 * window.
1219 *
1220 * Each time when a new block allocation is need, first try to allocate from
1221 * its own reservation. If it does not have a reservation window, instead of
1222 * looking for a free bit on bitmap first, then look up the reservation list to
1223 * see if it is inside somebody else's reservation window, we try to allocate a
1224 * reservation window for it starting from the goal first. Then do the block
1225 * allocation within the reservation window.
1226 *
1227 * This will avoid keeping on searching the reservation list again and
1228 * again when somebody is looking for a free block (without
1229 * reservation), and there are lots of free blocks, but they are all
1230 * being reserved.
1231 *
1232 * We use a red-black tree for the per-filesystem reservation list.
1233 *
1234 */
1235static ext3_grpblk_t
1236ext3_try_to_allocate_with_rsv(struct super_block *sb, handle_t *handle,
1237 unsigned int group, struct buffer_head *bitmap_bh,
1238 ext3_grpblk_t grp_goal,
1239 struct ext3_reserve_window_node * my_rsv,
1240 unsigned long *count, int *errp)
1241{
1242 ext3_fsblk_t group_first_block, group_last_block;
1243 ext3_grpblk_t ret = 0;
1244 int fatal;
1245 unsigned long num = *count;
1246
1247 *errp = 0;
1248
1249 /*
1250 * Make sure we use undo access for the bitmap, because it is critical
1251 * that we do the frozen_data COW on bitmap buffers in all cases even
1252 * if the buffer is in BJ_Forget state in the committing transaction.
1253 */
1254 BUFFER_TRACE(bitmap_bh, "get undo access for new block");
1255 fatal = ext3_journal_get_undo_access(handle, bitmap_bh);
1256 if (fatal) {
1257 *errp = fatal;
1258 return -1;
1259 }
1260
1261 /*
1262 * we don't deal with reservation when
1263 * filesystem is mounted without reservation
1264 * or the file is not a regular file
1265 * or last attempt to allocate a block with reservation turned on failed
1266 */
1267 if (my_rsv == NULL ) {
1268 ret = ext3_try_to_allocate(sb, handle, group, bitmap_bh,
1269 grp_goal, count, NULL);
1270 goto out;
1271 }
1272 /*
1273 * grp_goal is a group relative block number (if there is a goal)
1274 * 0 < grp_goal < EXT3_BLOCKS_PER_GROUP(sb)
1275 * first block is a filesystem wide block number
1276 * first block is the block number of the first block in this group
1277 */
1278 group_first_block = ext3_group_first_block_no(sb, group);
1279 group_last_block = group_first_block + (EXT3_BLOCKS_PER_GROUP(sb) - 1);
1280
1281 /*
1282 * Basically we will allocate a new block from inode's reservation
1283 * window.
1284 *
1285 * We need to allocate a new reservation window, if:
1286 * a) inode does not have a reservation window; or
1287 * b) last attempt to allocate a block from existing reservation
1288 * failed; or
1289 * c) we come here with a goal and with a reservation window
1290 *
1291 * We do not need to allocate a new reservation window if we come here
1292 * at the beginning with a goal and the goal is inside the window, or
1293 * we don't have a goal but already have a reservation window.
1294 * then we could go to allocate from the reservation window directly.
1295 */
1296 while (1) {
1297 if (rsv_is_empty(&my_rsv->rsv_window) || (ret < 0) ||
1298 !goal_in_my_reservation(&my_rsv->rsv_window,
1299 grp_goal, group, sb)) {
1300 if (my_rsv->rsv_goal_size < *count)
1301 my_rsv->rsv_goal_size = *count;
1302 ret = alloc_new_reservation(my_rsv, grp_goal, sb,
1303 group, bitmap_bh);
1304 if (ret < 0)
1305 break; /* failed */
1306
1307 if (!goal_in_my_reservation(&my_rsv->rsv_window,
1308 grp_goal, group, sb))
1309 grp_goal = -1;
1310 } else if (grp_goal > 0 &&
1311 (my_rsv->rsv_end-grp_goal+1) < *count)
1312 try_to_extend_reservation(my_rsv, sb,
1313 *count-my_rsv->rsv_end + grp_goal - 1);
1314
1315 if ((my_rsv->rsv_start > group_last_block) ||
1316 (my_rsv->rsv_end < group_first_block)) {
1317 rsv_window_dump(&EXT3_SB(sb)->s_rsv_window_root, 1);
1318 BUG();
1319 }
1320 ret = ext3_try_to_allocate(sb, handle, group, bitmap_bh,
1321 grp_goal, &num, &my_rsv->rsv_window);
1322 if (ret >= 0) {
1323 my_rsv->rsv_alloc_hit += num;
1324 *count = num;
1325 break; /* succeed */
1326 }
1327 num = *count;
1328 }
1329out:
1330 if (ret >= 0) {
1331 BUFFER_TRACE(bitmap_bh, "journal_dirty_metadata for "
1332 "bitmap block");
1333 fatal = ext3_journal_dirty_metadata(handle, bitmap_bh);
1334 if (fatal) {
1335 *errp = fatal;
1336 return -1;
1337 }
1338 return ret;
1339 }
1340
1341 BUFFER_TRACE(bitmap_bh, "journal_release_buffer");
1342 ext3_journal_release_buffer(handle, bitmap_bh);
1343 return ret;
1344}
1345
1346/**
1347 * ext3_has_free_blocks()
1348 * @sbi: in-core super block structure.
1349 *
1350 * Check if filesystem has at least 1 free block available for allocation.
1351 */
1352static int ext3_has_free_blocks(struct ext3_sb_info *sbi)
1353{
1354 ext3_fsblk_t free_blocks, root_blocks;
1355
1356 free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
1357 root_blocks = le32_to_cpu(sbi->s_es->s_r_blocks_count);
1358 if (free_blocks < root_blocks + 1 && !capable(CAP_SYS_RESOURCE) &&
1359 sbi->s_resuid != current->fsuid &&
1360 (sbi->s_resgid == 0 || !in_group_p (sbi->s_resgid))) {
1361 return 0;
1362 }
1363 return 1;
1364}
1365
1366/**
1367 * ext3_should_retry_alloc()
1368 * @sb: super block
1369 * @retries number of attemps has been made
1370 *
1371 * ext3_should_retry_alloc() is called when ENOSPC is returned, and if
1372 * it is profitable to retry the operation, this function will wait
1373 * for the current or commiting transaction to complete, and then
1374 * return TRUE.
1375 *
1376 * if the total number of retries exceed three times, return FALSE.
1377 */
1378int ext3_should_retry_alloc(struct super_block *sb, int *retries)
1379{
1380 if (!ext3_has_free_blocks(EXT3_SB(sb)) || (*retries)++ > 3)
1381 return 0;
1382
1383 jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id);
1384
1385 return journal_force_commit_nested(EXT3_SB(sb)->s_journal);
1386}
1387
1388/**
1389 * ext3_new_blocks() -- core block(s) allocation function
1390 * @handle: handle to this transaction
1391 * @inode: file inode
1392 * @goal: given target block(filesystem wide)
1393 * @count: target number of blocks to allocate
1394 * @errp: error code
1395 *
1396 * ext3_new_blocks uses a goal block to assist allocation. It tries to
1397 * allocate block(s) from the block group contains the goal block first. If that
1398 * fails, it will try to allocate block(s) from other block groups without
1399 * any specific goal block.
1400 *
1401 */
1402ext3_fsblk_t ext3_new_blocks(handle_t *handle, struct inode *inode,
1403 ext3_fsblk_t goal, unsigned long *count, int *errp)
1404{
1405 struct buffer_head *bitmap_bh = NULL;
1406 struct buffer_head *gdp_bh;
1407 int group_no;
1408 int goal_group;
1409 ext3_grpblk_t grp_target_blk; /* blockgroup relative goal block */
1410 ext3_grpblk_t grp_alloc_blk; /* blockgroup-relative allocated block*/
1411 ext3_fsblk_t ret_block; /* filesyetem-wide allocated block */
1412 int bgi; /* blockgroup iteration index */
1413 int fatal = 0, err;
1414 int performed_allocation = 0;
1415 ext3_grpblk_t free_blocks; /* number of free blocks in a group */
1416 struct super_block *sb;
1417 struct ext3_group_desc *gdp;
1418 struct ext3_super_block *es;
1419 struct ext3_sb_info *sbi;
1420 struct ext3_reserve_window_node *my_rsv = NULL;
1421 struct ext3_block_alloc_info *block_i;
1422 unsigned short windowsz = 0;
1423#ifdef EXT3FS_DEBUG
1424 static int goal_hits, goal_attempts;
1425#endif
1426 unsigned long ngroups;
1427 unsigned long num = *count;
1428
1429 *errp = -ENOSPC;
1430 sb = inode->i_sb;
1431 if (!sb) {
1432 printk("ext3_new_block: nonexistent device");
1433 return 0;
1434 }
1435
1436 /*
1437 * Check quota for allocation of this block.
1438 */
1439 if (DQUOT_ALLOC_BLOCK(inode, num)) {
1440 *errp = -EDQUOT;
1441 return 0;
1442 }
1443
1444 sbi = EXT3_SB(sb);
1445 es = EXT3_SB(sb)->s_es;
1446 ext3_debug("goal=%lu.\n", goal);
1447 /*
1448 * Allocate a block from reservation only when
1449 * filesystem is mounted with reservation(default,-o reservation), and
1450 * it's a regular file, and
1451 * the desired window size is greater than 0 (One could use ioctl
1452 * command EXT3_IOC_SETRSVSZ to set the window size to 0 to turn off
1453 * reservation on that particular file)
1454 */
1455 block_i = EXT3_I(inode)->i_block_alloc_info;
1456 if (block_i && ((windowsz = block_i->rsv_window_node.rsv_goal_size) > 0))
1457 my_rsv = &block_i->rsv_window_node;
1458
1459 if (!ext3_has_free_blocks(sbi)) {
1460 *errp = -ENOSPC;
1461 goto out;
1462 }
1463
1464 /*
1465 * First, test whether the goal block is free.
1466 */
1467 if (goal < le32_to_cpu(es->s_first_data_block) ||
1468 goal >= le32_to_cpu(es->s_blocks_count))
1469 goal = le32_to_cpu(es->s_first_data_block);
1470 group_no = (goal - le32_to_cpu(es->s_first_data_block)) /
1471 EXT3_BLOCKS_PER_GROUP(sb);
1472 goal_group = group_no;
1473retry_alloc:
1474 gdp = ext3_get_group_desc(sb, group_no, &gdp_bh);
1475 if (!gdp)
1476 goto io_error;
1477
1478 free_blocks = le16_to_cpu(gdp->bg_free_blocks_count);
1479 /*
1480 * if there is not enough free blocks to make a new resevation
1481 * turn off reservation for this allocation
1482 */
1483 if (my_rsv && (free_blocks < windowsz)
1484 && (rsv_is_empty(&my_rsv->rsv_window)))
1485 my_rsv = NULL;
1486
1487 if (free_blocks > 0) {
1488 grp_target_blk = ((goal - le32_to_cpu(es->s_first_data_block)) %
1489 EXT3_BLOCKS_PER_GROUP(sb));
1490 bitmap_bh = read_block_bitmap(sb, group_no);
1491 if (!bitmap_bh)
1492 goto io_error;
1493 grp_alloc_blk = ext3_try_to_allocate_with_rsv(sb, handle,
1494 group_no, bitmap_bh, grp_target_blk,
1495 my_rsv, &num, &fatal);
1496 if (fatal)
1497 goto out;
1498 if (grp_alloc_blk >= 0)
1499 goto allocated;
1500 }
1501
1502 ngroups = EXT3_SB(sb)->s_groups_count;
1503 smp_rmb();
1504
1505 /*
1506 * Now search the rest of the groups. We assume that
1507 * i and gdp correctly point to the last group visited.
1508 */
1509 for (bgi = 0; bgi < ngroups; bgi++) {
1510 group_no++;
1511 if (group_no >= ngroups)
1512 group_no = 0;
1513 gdp = ext3_get_group_desc(sb, group_no, &gdp_bh);
1514 if (!gdp) {
1515 *errp = -EIO;
1516 goto out;
1517 }
1518 free_blocks = le16_to_cpu(gdp->bg_free_blocks_count);
1519 /*
1520 * skip this group if the number of
1521 * free blocks is less than half of the reservation
1522 * window size.
1523 */
1524 if (free_blocks <= (windowsz/2))
1525 continue;
1526
1527 brelse(bitmap_bh);
1528 bitmap_bh = read_block_bitmap(sb, group_no);
1529 if (!bitmap_bh)
1530 goto io_error;
1531 /*
1532 * try to allocate block(s) from this group, without a goal(-1).
1533 */
1534 grp_alloc_blk = ext3_try_to_allocate_with_rsv(sb, handle,
1535 group_no, bitmap_bh, -1, my_rsv,
1536 &num, &fatal);
1537 if (fatal)
1538 goto out;
1539 if (grp_alloc_blk >= 0)
1540 goto allocated;
1541 }
1542 /*
1543 * We may end up a bogus ealier ENOSPC error due to
1544 * filesystem is "full" of reservations, but
1545 * there maybe indeed free blocks avaliable on disk
1546 * In this case, we just forget about the reservations
1547 * just do block allocation as without reservations.
1548 */
1549 if (my_rsv) {
1550 my_rsv = NULL;
1551 group_no = goal_group;
1552 goto retry_alloc;
1553 }
1554 /* No space left on the device */
1555 *errp = -ENOSPC;
1556 goto out;
1557
1558allocated:
1559
1560 ext3_debug("using block group %d(%d)\n",
1561 group_no, gdp->bg_free_blocks_count);
1562
1563 BUFFER_TRACE(gdp_bh, "get_write_access");
1564 fatal = ext3_journal_get_write_access(handle, gdp_bh);
1565 if (fatal)
1566 goto out;
1567
1568 ret_block = grp_alloc_blk + ext3_group_first_block_no(sb, group_no);
1569
1570 if (in_range(le32_to_cpu(gdp->bg_block_bitmap), ret_block, num) ||
1571 in_range(le32_to_cpu(gdp->bg_inode_bitmap), ret_block, num) ||
1572 in_range(ret_block, le32_to_cpu(gdp->bg_inode_table),
1573 EXT3_SB(sb)->s_itb_per_group) ||
1574 in_range(ret_block + num - 1, le32_to_cpu(gdp->bg_inode_table),
1575 EXT3_SB(sb)->s_itb_per_group))
1576 ext3_error(sb, "ext3_new_block",
1577 "Allocating block in system zone - "
1578 "blocks from "E3FSBLK", length %lu",
1579 ret_block, num);
1580
1581 performed_allocation = 1;
1582
1583#ifdef CONFIG_JBD_DEBUG
1584 {
1585 struct buffer_head *debug_bh;
1586
1587 /* Record bitmap buffer state in the newly allocated block */
1588 debug_bh = sb_find_get_block(sb, ret_block);
1589 if (debug_bh) {
1590 BUFFER_TRACE(debug_bh, "state when allocated");
1591 BUFFER_TRACE2(debug_bh, bitmap_bh, "bitmap state");
1592 brelse(debug_bh);
1593 }
1594 }
1595 jbd_lock_bh_state(bitmap_bh);
1596 spin_lock(sb_bgl_lock(sbi, group_no));
1597 if (buffer_jbd(bitmap_bh) && bh2jh(bitmap_bh)->b_committed_data) {
1598 int i;
1599
1600 for (i = 0; i < num; i++) {
1601 if (ext3_test_bit(grp_alloc_blk+i,
1602 bh2jh(bitmap_bh)->b_committed_data)) {
1603 printk("%s: block was unexpectedly set in "
1604 "b_committed_data\n", __FUNCTION__);
1605 }
1606 }
1607 }
1608 ext3_debug("found bit %d\n", grp_alloc_blk);
1609 spin_unlock(sb_bgl_lock(sbi, group_no));
1610 jbd_unlock_bh_state(bitmap_bh);
1611#endif
1612
1613 if (ret_block + num - 1 >= le32_to_cpu(es->s_blocks_count)) {
1614 ext3_error(sb, "ext3_new_block",
1615 "block("E3FSBLK") >= blocks count(%d) - "
1616 "block_group = %d, es == %p ", ret_block,
1617 le32_to_cpu(es->s_blocks_count), group_no, es);
1618 goto out;
1619 }
1620
1621 /*
1622 * It is up to the caller to add the new buffer to a journal
1623 * list of some description. We don't know in advance whether
1624 * the caller wants to use it as metadata or data.
1625 */
1626 ext3_debug("allocating block %lu. Goal hits %d of %d.\n",
1627 ret_block, goal_hits, goal_attempts);
1628
1629 spin_lock(sb_bgl_lock(sbi, group_no));
1630 gdp->bg_free_blocks_count =
1631 cpu_to_le16(le16_to_cpu(gdp->bg_free_blocks_count)-num);
1632 spin_unlock(sb_bgl_lock(sbi, group_no));
1633 percpu_counter_mod(&sbi->s_freeblocks_counter, -num);
1634
1635 BUFFER_TRACE(gdp_bh, "journal_dirty_metadata for group descriptor");
1636 err = ext3_journal_dirty_metadata(handle, gdp_bh);
1637 if (!fatal)
1638 fatal = err;
1639
1640 sb->s_dirt = 1;
1641 if (fatal)
1642 goto out;
1643
1644 *errp = 0;
1645 brelse(bitmap_bh);
1646 DQUOT_FREE_BLOCK(inode, *count-num);
1647 *count = num;
1648 return ret_block;
1649
1650io_error:
1651 *errp = -EIO;
1652out:
1653 if (fatal) {
1654 *errp = fatal;
1655 ext3_std_error(sb, fatal);
1656 }
1657 /*
1658 * Undo the block allocation
1659 */
1660 if (!performed_allocation)
1661 DQUOT_FREE_BLOCK(inode, *count);
1662 brelse(bitmap_bh);
1663 return 0;
1664}
1665
1666ext3_fsblk_t ext3_new_block(handle_t *handle, struct inode *inode,
1667 ext3_fsblk_t goal, int *errp)
1668{
1669 unsigned long count = 1;
1670
1671 return ext3_new_blocks(handle, inode, goal, &count, errp);
1672}
1673
1674/**
1675 * ext3_count_free_blocks() -- count filesystem free blocks
1676 * @sb: superblock
1677 *
1678 * Adds up the number of free blocks from each block group.
1679 */
1680ext3_fsblk_t ext3_count_free_blocks(struct super_block *sb)
1681{
1682 ext3_fsblk_t desc_count;
1683 struct ext3_group_desc *gdp;
1684 int i;
1685 unsigned long ngroups = EXT3_SB(sb)->s_groups_count;
1686#ifdef EXT3FS_DEBUG
1687 struct ext3_super_block *es;
1688 ext3_fsblk_t bitmap_count;
1689 unsigned long x;
1690 struct buffer_head *bitmap_bh = NULL;
1691
1692 es = EXT3_SB(sb)->s_es;
1693 desc_count = 0;
1694 bitmap_count = 0;
1695 gdp = NULL;
1696
1697 smp_rmb();
1698 for (i = 0; i < ngroups; i++) {
1699 gdp = ext3_get_group_desc(sb, i, NULL);
1700 if (!gdp)
1701 continue;
1702 desc_count += le16_to_cpu(gdp->bg_free_blocks_count);
1703 brelse(bitmap_bh);
1704 bitmap_bh = read_block_bitmap(sb, i);
1705 if (bitmap_bh == NULL)
1706 continue;
1707
1708 x = ext3_count_free(bitmap_bh, sb->s_blocksize);
1709 printk("group %d: stored = %d, counted = %lu\n",
1710 i, le16_to_cpu(gdp->bg_free_blocks_count), x);
1711 bitmap_count += x;
1712 }
1713 brelse(bitmap_bh);
1714 printk("ext3_count_free_blocks: stored = "E3FSBLK
1715 ", computed = "E3FSBLK", "E3FSBLK"\n",
1716 le32_to_cpu(es->s_free_blocks_count),
1717 desc_count, bitmap_count);
1718 return bitmap_count;
1719#else
1720 desc_count = 0;
1721 smp_rmb();
1722 for (i = 0; i < ngroups; i++) {
1723 gdp = ext3_get_group_desc(sb, i, NULL);
1724 if (!gdp)
1725 continue;
1726 desc_count += le16_to_cpu(gdp->bg_free_blocks_count);
1727 }
1728
1729 return desc_count;
1730#endif
1731}
1732
1733static inline int
1734block_in_use(ext3_fsblk_t block, struct super_block *sb, unsigned char *map)
1735{
1736 return ext3_test_bit ((block -
1737 le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block)) %
1738 EXT3_BLOCKS_PER_GROUP(sb), map);
1739}
1740
1741static inline int test_root(int a, int b)
1742{
1743 int num = b;
1744
1745 while (a > num)
1746 num *= b;
1747 return num == a;
1748}
1749
1750static int ext3_group_sparse(int group)
1751{
1752 if (group <= 1)
1753 return 1;
1754 if (!(group & 1))
1755 return 0;
1756 return (test_root(group, 7) || test_root(group, 5) ||
1757 test_root(group, 3));
1758}
1759
1760/**
1761 * ext3_bg_has_super - number of blocks used by the superblock in group
1762 * @sb: superblock for filesystem
1763 * @group: group number to check
1764 *
1765 * Return the number of blocks used by the superblock (primary or backup)
1766 * in this group. Currently this will be only 0 or 1.
1767 */
1768int ext3_bg_has_super(struct super_block *sb, int group)
1769{
1770 if (EXT3_HAS_RO_COMPAT_FEATURE(sb,
1771 EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER) &&
1772 !ext3_group_sparse(group))
1773 return 0;
1774 return 1;
1775}
1776
1777static unsigned long ext3_bg_num_gdb_meta(struct super_block *sb, int group)
1778{
1779 unsigned long metagroup = group / EXT3_DESC_PER_BLOCK(sb);
1780 unsigned long first = metagroup * EXT3_DESC_PER_BLOCK(sb);
1781 unsigned long last = first + EXT3_DESC_PER_BLOCK(sb) - 1;
1782
1783 if (group == first || group == first + 1 || group == last)
1784 return 1;
1785 return 0;
1786}
1787
1788static unsigned long ext3_bg_num_gdb_nometa(struct super_block *sb, int group)
1789{
1790 if (EXT3_HAS_RO_COMPAT_FEATURE(sb,
1791 EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER) &&
1792 !ext3_group_sparse(group))
1793 return 0;
1794 return EXT3_SB(sb)->s_gdb_count;
1795}
1796
1797/**
1798 * ext3_bg_num_gdb - number of blocks used by the group table in group
1799 * @sb: superblock for filesystem
1800 * @group: group number to check
1801 *
1802 * Return the number of blocks used by the group descriptor table
1803 * (primary or backup) in this group. In the future there may be a
1804 * different number of descriptor blocks in each group.
1805 */
1806unsigned long ext3_bg_num_gdb(struct super_block *sb, int group)
1807{
1808 unsigned long first_meta_bg =
1809 le32_to_cpu(EXT3_SB(sb)->s_es->s_first_meta_bg);
1810 unsigned long metagroup = group / EXT3_DESC_PER_BLOCK(sb);
1811
1812 if (!EXT3_HAS_INCOMPAT_FEATURE(sb,EXT3_FEATURE_INCOMPAT_META_BG) ||
1813 metagroup < first_meta_bg)
1814 return ext3_bg_num_gdb_nometa(sb,group);
1815
1816 return ext3_bg_num_gdb_meta(sb,group);
1817
1818}
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-11 02:14:56 -0500