2 * the_nilfs.c - the_nilfs shared structure.
4 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
20 * Written by Ryusuke Konishi <ryusuke@osrg.net>
24 #include <linux/buffer_head.h>
25 #include <linux/slab.h>
26 #include <linux/blkdev.h>
27 #include <linux/backing-dev.h>
28 #include <linux/crc32.h>
38 static LIST_HEAD(nilfs_objects);
39 static DEFINE_SPINLOCK(nilfs_lock);
41 static int nilfs_valid_sb(struct nilfs_super_block *sbp);
43 void nilfs_set_last_segment(struct the_nilfs *nilfs,
44 sector_t start_blocknr, u64 seq, __u64 cno)
46 spin_lock(&nilfs->ns_last_segment_lock);
47 nilfs->ns_last_pseg = start_blocknr;
48 nilfs->ns_last_seq = seq;
49 nilfs->ns_last_cno = cno;
51 if (!nilfs_sb_dirty(nilfs)) {
52 if (nilfs->ns_prev_seq == nilfs->ns_last_seq)
55 set_nilfs_sb_dirty(nilfs);
57 nilfs->ns_prev_seq = nilfs->ns_last_seq;
60 spin_unlock(&nilfs->ns_last_segment_lock);
64 * alloc_nilfs - allocate the_nilfs structure
65 * @bdev: block device to which the_nilfs is related
67 * alloc_nilfs() allocates memory for the_nilfs and
68 * initializes its reference count and locks.
70 * Return Value: On success, pointer to the_nilfs is returned.
71 * On error, NULL is returned.
73 static struct the_nilfs *alloc_nilfs(struct block_device *bdev)
75 struct the_nilfs *nilfs;
77 nilfs = kzalloc(sizeof(*nilfs), GFP_KERNEL);
81 nilfs->ns_bdev = bdev;
82 atomic_set(&nilfs->ns_count, 1);
83 atomic_set(&nilfs->ns_ndirtyblks, 0);
84 init_rwsem(&nilfs->ns_sem);
85 init_rwsem(&nilfs->ns_super_sem);
86 mutex_init(&nilfs->ns_mount_mutex);
87 init_rwsem(&nilfs->ns_writer_sem);
88 INIT_LIST_HEAD(&nilfs->ns_list);
89 INIT_LIST_HEAD(&nilfs->ns_supers);
90 spin_lock_init(&nilfs->ns_last_segment_lock);
91 nilfs->ns_gc_inodes_h = NULL;
92 init_rwsem(&nilfs->ns_segctor_sem);
98 * find_or_create_nilfs - find or create nilfs object
99 * @bdev: block device to which the_nilfs is related
101 * find_nilfs() looks up an existent nilfs object created on the
102 * device and gets the reference count of the object. If no nilfs object
103 * is found on the device, a new nilfs object is allocated.
105 * Return Value: On success, pointer to the nilfs object is returned.
106 * On error, NULL is returned.
108 struct the_nilfs *find_or_create_nilfs(struct block_device *bdev)
110 struct the_nilfs *nilfs, *new = NULL;
113 spin_lock(&nilfs_lock);
114 list_for_each_entry(nilfs, &nilfs_objects, ns_list) {
115 if (nilfs->ns_bdev == bdev) {
117 spin_unlock(&nilfs_lock);
120 return nilfs; /* existing object */
124 list_add_tail(&new->ns_list, &nilfs_objects);
125 spin_unlock(&nilfs_lock);
126 return new; /* new object */
128 spin_unlock(&nilfs_lock);
130 new = alloc_nilfs(bdev);
133 return NULL; /* insufficient memory */
137 * put_nilfs - release a reference to the_nilfs
138 * @nilfs: the_nilfs structure to be released
140 * put_nilfs() decrements a reference counter of the_nilfs.
141 * If the reference count reaches zero, the_nilfs is freed.
143 void put_nilfs(struct the_nilfs *nilfs)
145 spin_lock(&nilfs_lock);
146 if (!atomic_dec_and_test(&nilfs->ns_count)) {
147 spin_unlock(&nilfs_lock);
150 list_del_init(&nilfs->ns_list);
151 spin_unlock(&nilfs_lock);
154 * Increment of ns_count never occurs below because the caller
155 * of get_nilfs() holds at least one reference to the_nilfs.
156 * Thus its exclusion control is not required here.
160 if (nilfs_loaded(nilfs)) {
161 nilfs_mdt_destroy(nilfs->ns_sufile);
162 nilfs_mdt_destroy(nilfs->ns_cpfile);
163 nilfs_mdt_destroy(nilfs->ns_dat);
164 nilfs_mdt_destroy(nilfs->ns_gc_dat);
166 if (nilfs_init(nilfs)) {
167 nilfs_destroy_gccache(nilfs);
168 brelse(nilfs->ns_sbh[0]);
169 brelse(nilfs->ns_sbh[1]);
174 static int nilfs_load_super_root(struct the_nilfs *nilfs, sector_t sr_block)
176 struct buffer_head *bh_sr;
177 struct nilfs_super_root *raw_sr;
178 struct nilfs_super_block **sbp = nilfs->ns_sbp;
179 unsigned dat_entry_size, segment_usage_size, checkpoint_size;
183 err = nilfs_read_super_root_block(nilfs, sr_block, &bh_sr, 1);
187 down_read(&nilfs->ns_sem);
188 dat_entry_size = le16_to_cpu(sbp[0]->s_dat_entry_size);
189 checkpoint_size = le16_to_cpu(sbp[0]->s_checkpoint_size);
190 segment_usage_size = le16_to_cpu(sbp[0]->s_segment_usage_size);
191 up_read(&nilfs->ns_sem);
193 inode_size = nilfs->ns_inode_size;
196 nilfs->ns_dat = nilfs_dat_new(nilfs, dat_entry_size);
197 if (unlikely(!nilfs->ns_dat))
200 nilfs->ns_gc_dat = nilfs_dat_new(nilfs, dat_entry_size);
201 if (unlikely(!nilfs->ns_gc_dat))
204 nilfs->ns_cpfile = nilfs_cpfile_new(nilfs, checkpoint_size);
205 if (unlikely(!nilfs->ns_cpfile))
208 nilfs->ns_sufile = nilfs_sufile_new(nilfs, segment_usage_size);
209 if (unlikely(!nilfs->ns_sufile))
212 nilfs_mdt_set_shadow(nilfs->ns_dat, nilfs->ns_gc_dat);
214 err = nilfs_dat_read(nilfs->ns_dat, (void *)bh_sr->b_data +
215 NILFS_SR_DAT_OFFSET(inode_size));
219 err = nilfs_cpfile_read(nilfs->ns_cpfile, (void *)bh_sr->b_data +
220 NILFS_SR_CPFILE_OFFSET(inode_size));
224 err = nilfs_sufile_read(nilfs->ns_sufile, (void *)bh_sr->b_data +
225 NILFS_SR_SUFILE_OFFSET(inode_size));
229 raw_sr = (struct nilfs_super_root *)bh_sr->b_data;
230 nilfs->ns_nongc_ctime = le64_to_cpu(raw_sr->sr_nongc_ctime);
237 nilfs_mdt_destroy(nilfs->ns_sufile);
240 nilfs_mdt_destroy(nilfs->ns_cpfile);
243 nilfs_mdt_destroy(nilfs->ns_gc_dat);
246 nilfs_mdt_destroy(nilfs->ns_dat);
250 static void nilfs_init_recovery_info(struct nilfs_recovery_info *ri)
252 memset(ri, 0, sizeof(*ri));
253 INIT_LIST_HEAD(&ri->ri_used_segments);
256 static void nilfs_clear_recovery_info(struct nilfs_recovery_info *ri)
258 nilfs_dispose_segment_list(&ri->ri_used_segments);
262 * nilfs_store_log_cursor - load log cursor from a super block
263 * @nilfs: nilfs object
264 * @sbp: buffer storing super block to be read
266 * nilfs_store_log_cursor() reads the last position of the log
267 * containing a super root from a given super block, and initializes
268 * relevant information on the nilfs object preparatory for log
269 * scanning and recovery.
271 static int nilfs_store_log_cursor(struct the_nilfs *nilfs,
272 struct nilfs_super_block *sbp)
276 nilfs->ns_last_pseg = le64_to_cpu(sbp->s_last_pseg);
277 nilfs->ns_last_cno = le64_to_cpu(sbp->s_last_cno);
278 nilfs->ns_last_seq = le64_to_cpu(sbp->s_last_seq);
280 nilfs->ns_prev_seq = nilfs->ns_last_seq;
281 nilfs->ns_seg_seq = nilfs->ns_last_seq;
283 nilfs_get_segnum_of_block(nilfs, nilfs->ns_last_pseg);
284 nilfs->ns_cno = nilfs->ns_last_cno + 1;
285 if (nilfs->ns_segnum >= nilfs->ns_nsegments) {
286 printk(KERN_ERR "NILFS invalid last segment number.\n");
293 * load_nilfs - load and recover the nilfs
294 * @nilfs: the_nilfs structure to be released
295 * @sbi: nilfs_sb_info used to recover past segment
297 * load_nilfs() searches and load the latest super root,
298 * attaches the last segment, and does recovery if needed.
299 * The caller must call this exclusively for simultaneous mounts.
301 int load_nilfs(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi)
303 struct nilfs_recovery_info ri;
304 unsigned int s_flags = sbi->s_super->s_flags;
305 int really_read_only = bdev_read_only(nilfs->ns_bdev);
306 int valid_fs = nilfs_valid_fs(nilfs);
309 if (nilfs_loaded(nilfs)) {
311 ((s_flags & MS_RDONLY) && nilfs_test_opt(sbi, NORECOVERY)))
313 printk(KERN_ERR "NILFS: the filesystem is in an incomplete "
314 "recovery state.\n");
319 printk(KERN_WARNING "NILFS warning: mounting unchecked fs\n");
320 if (s_flags & MS_RDONLY) {
321 printk(KERN_INFO "NILFS: INFO: recovery "
322 "required for readonly filesystem.\n");
323 printk(KERN_INFO "NILFS: write access will "
324 "be enabled during recovery.\n");
328 nilfs_init_recovery_info(&ri);
330 err = nilfs_search_super_root(nilfs, &ri);
332 struct nilfs_super_block **sbp = nilfs->ns_sbp;
338 if (!nilfs_valid_sb(sbp[1])) {
340 "NILFS warning: unable to fall back to spare"
345 "NILFS: try rollback from an earlier position\n");
348 * restore super block with its spare and reconfigure
349 * relevant states of the nilfs object.
351 memcpy(sbp[0], sbp[1], nilfs->ns_sbsize);
352 nilfs->ns_crc_seed = le32_to_cpu(sbp[0]->s_crc_seed);
353 nilfs->ns_sbwtime = le64_to_cpu(sbp[0]->s_wtime);
355 /* verify consistency between two super blocks */
356 blocksize = BLOCK_SIZE << le32_to_cpu(sbp[0]->s_log_block_size);
357 if (blocksize != nilfs->ns_blocksize) {
359 "NILFS warning: blocksize differs between "
360 "two super blocks (%d != %d)\n",
361 blocksize, nilfs->ns_blocksize);
365 err = nilfs_store_log_cursor(nilfs, sbp[0]);
369 /* drop clean flag to allow roll-forward and recovery */
370 nilfs->ns_mount_state &= ~NILFS_VALID_FS;
373 err = nilfs_search_super_root(nilfs, &ri);
378 err = nilfs_load_super_root(nilfs, ri.ri_super_root);
380 printk(KERN_ERR "NILFS: error loading super root.\n");
387 if (s_flags & MS_RDONLY) {
388 if (nilfs_test_opt(sbi, NORECOVERY)) {
389 printk(KERN_INFO "NILFS: norecovery option specified. "
390 "skipping roll-forward recovery\n");
393 if (really_read_only) {
394 printk(KERN_ERR "NILFS: write access "
395 "unavailable, cannot proceed.\n");
399 sbi->s_super->s_flags &= ~MS_RDONLY;
400 } else if (nilfs_test_opt(sbi, NORECOVERY)) {
401 printk(KERN_ERR "NILFS: recovery cancelled because norecovery "
402 "option was specified for a read/write mount\n");
407 err = nilfs_salvage_orphan_logs(nilfs, sbi, &ri);
411 down_write(&nilfs->ns_sem);
412 nilfs->ns_mount_state |= NILFS_VALID_FS; /* set "clean" flag */
413 err = nilfs_cleanup_super(sbi);
414 up_write(&nilfs->ns_sem);
417 printk(KERN_ERR "NILFS: failed to update super block. "
418 "recovery unfinished.\n");
421 printk(KERN_INFO "NILFS: recovery complete.\n");
424 set_nilfs_loaded(nilfs);
425 nilfs_clear_recovery_info(&ri);
426 sbi->s_super->s_flags = s_flags;
430 printk(KERN_ERR "NILFS: error searching super root.\n");
434 nilfs_mdt_destroy(nilfs->ns_cpfile);
435 nilfs_mdt_destroy(nilfs->ns_sufile);
436 nilfs_mdt_destroy(nilfs->ns_dat);
439 nilfs_clear_recovery_info(&ri);
440 sbi->s_super->s_flags = s_flags;
444 static unsigned long long nilfs_max_size(unsigned int blkbits)
446 unsigned int max_bits;
447 unsigned long long res = MAX_LFS_FILESIZE; /* page cache limit */
449 max_bits = blkbits + NILFS_BMAP_KEY_BIT; /* bmap size limit */
451 res = min_t(unsigned long long, res, (1ULL << max_bits) - 1);
455 static int nilfs_store_disk_layout(struct the_nilfs *nilfs,
456 struct nilfs_super_block *sbp)
458 if (le32_to_cpu(sbp->s_rev_level) != NILFS_CURRENT_REV) {
459 printk(KERN_ERR "NILFS: revision mismatch "
460 "(superblock rev.=%d.%d, current rev.=%d.%d). "
461 "Please check the version of mkfs.nilfs.\n",
462 le32_to_cpu(sbp->s_rev_level),
463 le16_to_cpu(sbp->s_minor_rev_level),
464 NILFS_CURRENT_REV, NILFS_MINOR_REV);
467 nilfs->ns_sbsize = le16_to_cpu(sbp->s_bytes);
468 if (nilfs->ns_sbsize > BLOCK_SIZE)
471 nilfs->ns_inode_size = le16_to_cpu(sbp->s_inode_size);
472 nilfs->ns_first_ino = le32_to_cpu(sbp->s_first_ino);
474 nilfs->ns_blocks_per_segment = le32_to_cpu(sbp->s_blocks_per_segment);
475 if (nilfs->ns_blocks_per_segment < NILFS_SEG_MIN_BLOCKS) {
476 printk(KERN_ERR "NILFS: too short segment.\n");
480 nilfs->ns_first_data_block = le64_to_cpu(sbp->s_first_data_block);
481 nilfs->ns_nsegments = le64_to_cpu(sbp->s_nsegments);
482 nilfs->ns_r_segments_percentage =
483 le32_to_cpu(sbp->s_r_segments_percentage);
485 max_t(unsigned long, NILFS_MIN_NRSVSEGS,
486 DIV_ROUND_UP(nilfs->ns_nsegments *
487 nilfs->ns_r_segments_percentage, 100));
488 nilfs->ns_crc_seed = le32_to_cpu(sbp->s_crc_seed);
492 static int nilfs_valid_sb(struct nilfs_super_block *sbp)
494 static unsigned char sum[4];
495 const int sumoff = offsetof(struct nilfs_super_block, s_sum);
499 if (!sbp || le16_to_cpu(sbp->s_magic) != NILFS_SUPER_MAGIC)
501 bytes = le16_to_cpu(sbp->s_bytes);
502 if (bytes > BLOCK_SIZE)
504 crc = crc32_le(le32_to_cpu(sbp->s_crc_seed), (unsigned char *)sbp,
506 crc = crc32_le(crc, sum, 4);
507 crc = crc32_le(crc, (unsigned char *)sbp + sumoff + 4,
509 return crc == le32_to_cpu(sbp->s_sum);
512 static int nilfs_sb2_bad_offset(struct nilfs_super_block *sbp, u64 offset)
514 return offset < ((le64_to_cpu(sbp->s_nsegments) *
515 le32_to_cpu(sbp->s_blocks_per_segment)) <<
516 (le32_to_cpu(sbp->s_log_block_size) + 10));
519 static void nilfs_release_super_block(struct the_nilfs *nilfs)
523 for (i = 0; i < 2; i++) {
524 if (nilfs->ns_sbp[i]) {
525 brelse(nilfs->ns_sbh[i]);
526 nilfs->ns_sbh[i] = NULL;
527 nilfs->ns_sbp[i] = NULL;
532 void nilfs_fall_back_super_block(struct the_nilfs *nilfs)
534 brelse(nilfs->ns_sbh[0]);
535 nilfs->ns_sbh[0] = nilfs->ns_sbh[1];
536 nilfs->ns_sbp[0] = nilfs->ns_sbp[1];
537 nilfs->ns_sbh[1] = NULL;
538 nilfs->ns_sbp[1] = NULL;
541 void nilfs_swap_super_block(struct the_nilfs *nilfs)
543 struct buffer_head *tsbh = nilfs->ns_sbh[0];
544 struct nilfs_super_block *tsbp = nilfs->ns_sbp[0];
546 nilfs->ns_sbh[0] = nilfs->ns_sbh[1];
547 nilfs->ns_sbp[0] = nilfs->ns_sbp[1];
548 nilfs->ns_sbh[1] = tsbh;
549 nilfs->ns_sbp[1] = tsbp;
552 static int nilfs_load_super_block(struct the_nilfs *nilfs,
553 struct super_block *sb, int blocksize,
554 struct nilfs_super_block **sbpp)
556 struct nilfs_super_block **sbp = nilfs->ns_sbp;
557 struct buffer_head **sbh = nilfs->ns_sbh;
558 u64 sb2off = NILFS_SB2_OFFSET_BYTES(nilfs->ns_bdev->bd_inode->i_size);
559 int valid[2], swp = 0;
561 sbp[0] = nilfs_read_super_block(sb, NILFS_SB_OFFSET_BYTES, blocksize,
563 sbp[1] = nilfs_read_super_block(sb, sb2off, blocksize, &sbh[1]);
567 printk(KERN_ERR "NILFS: unable to read superblock\n");
571 "NILFS warning: unable to read primary superblock\n");
574 "NILFS warning: unable to read secondary superblock\n");
577 * Compare two super blocks and set 1 in swp if the secondary
578 * super block is valid and newer. Otherwise, set 0 in swp.
580 valid[0] = nilfs_valid_sb(sbp[0]);
581 valid[1] = nilfs_valid_sb(sbp[1]);
582 swp = valid[1] && (!valid[0] ||
583 le64_to_cpu(sbp[1]->s_last_cno) >
584 le64_to_cpu(sbp[0]->s_last_cno));
586 if (valid[swp] && nilfs_sb2_bad_offset(sbp[swp], sb2off)) {
593 nilfs_release_super_block(nilfs);
594 printk(KERN_ERR "NILFS: Can't find nilfs on dev %s.\n",
600 printk(KERN_WARNING "NILFS warning: broken superblock. "
601 "using spare superblock.\n");
602 nilfs_swap_super_block(nilfs);
605 nilfs->ns_sbwcount = 0;
606 nilfs->ns_sbwtime = le64_to_cpu(sbp[0]->s_wtime);
607 nilfs->ns_prot_seq = le64_to_cpu(sbp[valid[1] & !swp]->s_last_seq);
613 * init_nilfs - initialize a NILFS instance.
614 * @nilfs: the_nilfs structure
615 * @sbi: nilfs_sb_info
617 * @data: mount options
619 * init_nilfs() performs common initialization per block device (e.g.
620 * reading the super block, getting disk layout information, initializing
621 * shared fields in the_nilfs). It takes on some portion of the jobs
622 * typically done by a fill_super() routine. This division arises from
623 * the nature that multiple NILFS instances may be simultaneously
624 * mounted on a device.
625 * For multiple mounts on the same device, only the first mount
626 * invokes these tasks.
628 * Return Value: On success, 0 is returned. On error, a negative error
631 int init_nilfs(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi, char *data)
633 struct super_block *sb = sbi->s_super;
634 struct nilfs_super_block *sbp;
635 struct backing_dev_info *bdi;
639 down_write(&nilfs->ns_sem);
640 if (nilfs_init(nilfs)) {
641 /* Load values from existing the_nilfs */
642 sbp = nilfs->ns_sbp[0];
643 err = nilfs_store_magic_and_option(sb, sbp, data);
647 blocksize = BLOCK_SIZE << le32_to_cpu(sbp->s_log_block_size);
648 if (sb->s_blocksize != blocksize &&
649 !sb_set_blocksize(sb, blocksize)) {
650 printk(KERN_ERR "NILFS: blocksize %d unfit to device\n",
654 sb->s_maxbytes = nilfs_max_size(sb->s_blocksize_bits);
658 blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
660 printk(KERN_ERR "NILFS: unable to set blocksize\n");
664 err = nilfs_load_super_block(nilfs, sb, blocksize, &sbp);
668 err = nilfs_store_magic_and_option(sb, sbp, data);
672 blocksize = BLOCK_SIZE << le32_to_cpu(sbp->s_log_block_size);
673 if (sb->s_blocksize != blocksize) {
674 int hw_blocksize = bdev_logical_block_size(sb->s_bdev);
676 if (blocksize < hw_blocksize) {
678 "NILFS: blocksize %d too small for device "
679 "(sector-size = %d).\n",
680 blocksize, hw_blocksize);
684 nilfs_release_super_block(nilfs);
685 sb_set_blocksize(sb, blocksize);
687 err = nilfs_load_super_block(nilfs, sb, blocksize, &sbp);
690 /* not failed_sbh; sbh is released automatically
691 when reloading fails. */
693 nilfs->ns_blocksize_bits = sb->s_blocksize_bits;
694 nilfs->ns_blocksize = blocksize;
696 err = nilfs_store_disk_layout(nilfs, sbp);
700 sb->s_maxbytes = nilfs_max_size(sb->s_blocksize_bits);
702 nilfs->ns_mount_state = le16_to_cpu(sbp->s_state);
704 bdi = nilfs->ns_bdev->bd_inode->i_mapping->backing_dev_info;
705 nilfs->ns_bdi = bdi ? : &default_backing_dev_info;
707 err = nilfs_store_log_cursor(nilfs, sbp);
711 /* Initialize gcinode cache */
712 err = nilfs_init_gccache(nilfs);
716 set_nilfs_init(nilfs);
719 up_write(&nilfs->ns_sem);
723 nilfs_release_super_block(nilfs);
727 int nilfs_discard_segments(struct the_nilfs *nilfs, __u64 *segnump,
730 sector_t seg_start, seg_end;
731 sector_t start = 0, nblocks = 0;
732 unsigned int sects_per_block;
736 sects_per_block = (1 << nilfs->ns_blocksize_bits) /
737 bdev_logical_block_size(nilfs->ns_bdev);
738 for (sn = segnump; sn < segnump + nsegs; sn++) {
739 nilfs_get_segment_range(nilfs, *sn, &seg_start, &seg_end);
743 nblocks = seg_end - seg_start + 1;
744 } else if (start + nblocks == seg_start) {
745 nblocks += seg_end - seg_start + 1;
747 ret = blkdev_issue_discard(nilfs->ns_bdev,
748 start * sects_per_block,
749 nblocks * sects_per_block,
758 ret = blkdev_issue_discard(nilfs->ns_bdev,
759 start * sects_per_block,
760 nblocks * sects_per_block,
761 GFP_NOFS, BLKDEV_IFL_BARRIER);
765 int nilfs_count_free_blocks(struct the_nilfs *nilfs, sector_t *nblocks)
767 struct inode *dat = nilfs_dat_inode(nilfs);
768 unsigned long ncleansegs;
770 down_read(&NILFS_MDT(dat)->mi_sem); /* XXX */
771 ncleansegs = nilfs_sufile_get_ncleansegs(nilfs->ns_sufile);
772 up_read(&NILFS_MDT(dat)->mi_sem); /* XXX */
773 *nblocks = (sector_t)ncleansegs * nilfs->ns_blocks_per_segment;
777 int nilfs_near_disk_full(struct the_nilfs *nilfs)
779 unsigned long ncleansegs, nincsegs;
781 ncleansegs = nilfs_sufile_get_ncleansegs(nilfs->ns_sufile);
782 nincsegs = atomic_read(&nilfs->ns_ndirtyblks) /
783 nilfs->ns_blocks_per_segment + 1;
785 return ncleansegs <= nilfs->ns_nrsvsegs + nincsegs;
789 * nilfs_find_sbinfo - find existing nilfs_sb_info structure
790 * @nilfs: nilfs object
791 * @rw_mount: mount type (non-zero value for read/write mount)
792 * @cno: checkpoint number (zero for read-only mount)
794 * nilfs_find_sbinfo() returns the nilfs_sb_info structure which
795 * @rw_mount and @cno (in case of snapshots) matched. If no instance
796 * was found, NULL is returned. Although the super block instance can
797 * be unmounted after this function returns, the nilfs_sb_info struct
798 * is kept on memory until nilfs_put_sbinfo() is called.
800 struct nilfs_sb_info *nilfs_find_sbinfo(struct the_nilfs *nilfs,
801 int rw_mount, __u64 cno)
803 struct nilfs_sb_info *sbi;
805 down_read(&nilfs->ns_super_sem);
807 * The SNAPSHOT flag and sb->s_flags are supposed to be
808 * protected with nilfs->ns_super_sem.
810 sbi = nilfs->ns_current;
812 if (sbi && !(sbi->s_super->s_flags & MS_RDONLY))
813 goto found; /* read/write mount */
816 } else if (cno == 0) {
817 if (sbi && (sbi->s_super->s_flags & MS_RDONLY))
818 goto found; /* read-only mount */
823 list_for_each_entry(sbi, &nilfs->ns_supers, s_list) {
824 if (nilfs_test_opt(sbi, SNAPSHOT) &&
825 sbi->s_snapshot_cno == cno)
826 goto found; /* snapshot mount */
829 up_read(&nilfs->ns_super_sem);
833 atomic_inc(&sbi->s_count);
834 up_read(&nilfs->ns_super_sem);
838 int nilfs_checkpoint_is_mounted(struct the_nilfs *nilfs, __u64 cno,
841 struct nilfs_sb_info *sbi;
844 down_read(&nilfs->ns_super_sem);
845 if (cno == 0 || cno > nilfs->ns_cno)
848 list_for_each_entry(sbi, &nilfs->ns_supers, s_list) {
849 if (sbi->s_snapshot_cno == cno &&
850 (!snapshot_mount || nilfs_test_opt(sbi, SNAPSHOT))) {
851 /* exclude read-only mounts */
856 /* for protecting recent checkpoints */
857 if (cno >= nilfs_last_cno(nilfs))
861 up_read(&nilfs->ns_super_sem);