/* * the_nilfs.c - the_nilfs shared structure. * * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * Written by Ryusuke Konishi. * */ #include <linux/buffer_head.h> #include <linux/slab.h> #include <linux/blkdev.h> #include <linux/backing-dev.h> #include <linux/random.h> #include <linux/crc32.h> #include "nilfs.h" #include "segment.h" #include "alloc.h" #include "cpfile.h" #include "sufile.h" #include "dat.h" #include "segbuf.h" static int nilfs_valid_sb(struct nilfs_super_block *sbp); void nilfs_set_last_segment(struct the_nilfs *nilfs, sector_t start_blocknr, u64 seq, __u64 cno) { spin_lock(&nilfs->ns_last_segment_lock); nilfs->ns_last_pseg = start_blocknr; nilfs->ns_last_seq = seq; nilfs->ns_last_cno = cno; if (!nilfs_sb_dirty(nilfs)) { if (nilfs->ns_prev_seq == nilfs->ns_last_seq) goto stay_cursor; set_nilfs_sb_dirty(nilfs); } nilfs->ns_prev_seq = nilfs->ns_last_seq; stay_cursor: spin_unlock(&nilfs->ns_last_segment_lock); } /** * alloc_nilfs - allocate a nilfs object * @sb: super block instance * * Return Value: On success, pointer to the_nilfs is returned. * On error, NULL is returned. */ struct the_nilfs *alloc_nilfs(struct super_block *sb) { struct the_nilfs *nilfs; nilfs = kzalloc(sizeof(*nilfs), GFP_KERNEL); if (!nilfs) return NULL; nilfs->ns_sb = sb; nilfs->ns_bdev = sb->s_bdev; atomic_set(&nilfs->ns_ndirtyblks, 0); init_rwsem(&nilfs->ns_sem); mutex_init(&nilfs->ns_snapshot_mount_mutex); INIT_LIST_HEAD(&nilfs->ns_dirty_files); INIT_LIST_HEAD(&nilfs->ns_gc_inodes); spin_lock_init(&nilfs->ns_inode_lock); spin_lock_init(&nilfs->ns_next_gen_lock); spin_lock_init(&nilfs->ns_last_segment_lock); nilfs->ns_cptree = RB_ROOT; spin_lock_init(&nilfs->ns_cptree_lock); init_rwsem(&nilfs->ns_segctor_sem); nilfs->ns_sb_update_freq = NILFS_SB_FREQ; return nilfs; } /** * destroy_nilfs - destroy nilfs object * @nilfs: nilfs object to be released */ void destroy_nilfs(struct the_nilfs *nilfs) { might_sleep(); if (nilfs_init(nilfs)) { nilfs_sysfs_delete_device_group(nilfs); brelse(nilfs->ns_sbh[0]); brelse(nilfs->ns_sbh[1]); } kfree(nilfs); } static int nilfs_load_super_root(struct the_nilfs *nilfs, struct super_block *sb, sector_t sr_block) { struct buffer_head *bh_sr; struct nilfs_super_root *raw_sr; struct nilfs_super_block **sbp = nilfs->ns_sbp; struct nilfs_inode *rawi; unsigned int dat_entry_size, segment_usage_size, checkpoint_size; unsigned int inode_size; int err; err = nilfs_read_super_root_block(nilfs, sr_block, &bh_sr, 1); if (unlikely(err)) return err; down_read(&nilfs->ns_sem); dat_entry_size = le16_to_cpu(sbp[0]->s_dat_entry_size); checkpoint_size = le16_to_cpu(sbp[0]->s_checkpoint_size); segment_usage_size = le16_to_cpu(sbp[0]->s_segment_usage_size); up_read(&nilfs->ns_sem); inode_size = nilfs->ns_inode_size; rawi = (void *)bh_sr->b_data + NILFS_SR_DAT_OFFSET(inode_size); err = nilfs_dat_read(sb, dat_entry_size, rawi, &nilfs->ns_dat); if (err) goto failed; rawi = (void *)bh_sr->b_data + NILFS_SR_CPFILE_OFFSET(inode_size); err = nilfs_cpfile_read(sb, checkpoint_size, rawi, &nilfs->ns_cpfile); if (err) goto failed_dat; rawi = (void *)bh_sr->b_data + NILFS_SR_SUFILE_OFFSET(inode_size); err = nilfs_sufile_read(sb, segment_usage_size, rawi, &nilfs->ns_sufile); if (err) goto failed_cpfile; raw_sr = (struct nilfs_super_root *)bh_sr->b_data; nilfs->ns_nongc_ctime = le64_to_cpu(raw_sr->sr_nongc_ctime); failed: brelse(bh_sr); return err; failed_cpfile: iput(nilfs->ns_cpfile); failed_dat: iput(nilfs->ns_dat); goto failed; } static void nilfs_init_recovery_info(struct nilfs_recovery_info *ri) { memset(ri, 0, sizeof(*ri)); INIT_LIST_HEAD(&ri->ri_used_segments); } static void nilfs_clear_recovery_info(struct nilfs_recovery_info *ri) { nilfs_dispose_segment_list(&ri->ri_used_segments); } /** * nilfs_store_log_cursor - load log cursor from a super block * @nilfs: nilfs object * @sbp: buffer storing super block to be read * * nilfs_store_log_cursor() reads the last position of the log * containing a super root from a given super block, and initializes * relevant information on the nilfs object preparatory for log * scanning and recovery. */ static int nilfs_store_log_cursor(struct the_nilfs *nilfs, struct nilfs_super_block *sbp) { int ret = 0; nilfs->ns_last_pseg = le64_to_cpu(sbp->s_last_pseg); nilfs->ns_last_cno = le64_to_cpu(sbp->s_last_cno); nilfs->ns_last_seq = le64_to_cpu(sbp->s_last_seq); nilfs->ns_prev_seq = nilfs->ns_last_seq; nilfs->ns_seg_seq = nilfs->ns_last_seq; nilfs->ns_segnum = nilfs_get_segnum_of_block(nilfs, nilfs->ns_last_pseg); nilfs->ns_cno = nilfs->ns_last_cno + 1; if (nilfs->ns_segnum >= nilfs->ns_nsegments) { nilfs_msg(nilfs->ns_sb, KERN_ERR, "pointed segment number is out of range: segnum=%llu, nsegments=%lu", (unsigned long long)nilfs->ns_segnum, nilfs->ns_nsegments); ret = -EINVAL; } return ret; } /** * load_nilfs - load and recover the nilfs * @nilfs: the_nilfs structure to be released * @sb: super block isntance used to recover past segment * * load_nilfs() searches and load the latest super root, * attaches the last segment, and does recovery if needed. * The caller must call this exclusively for simultaneous mounts. */ int load_nilfs(struct the_nilfs *nilfs, struct super_block *sb) { struct nilfs_recovery_info ri; unsigned int s_flags = sb->s_flags; int really_read_only = bdev_read_only(nilfs->ns_bdev); int valid_fs = nilfs_valid_fs(nilfs); int err; if (!valid_fs) { nilfs_msg(sb, KERN_WARNING, "mounting unchecked fs"); if (s_flags & MS_RDONLY) { nilfs_msg(sb, KERN_INFO, "recovery required for readonly filesystem"); nilfs_msg(sb, KERN_INFO, "write access will be enabled during recovery"); } } nilfs_init_recovery_info(&ri); err = nilfs_search_super_root(nilfs, &ri); if (unlikely(err)) { struct nilfs_super_block **sbp = nilfs->ns_sbp; int blocksize; if (err != -EINVAL) goto scan_error; if (!nilfs_valid_sb(sbp[1])) { nilfs_msg(sb, KERN_WARNING, "unable to fall back to spare super block"); goto scan_error; } nilfs_msg(sb, KERN_INFO, "trying rollback from an earlier position"); /* * restore super block with its spare and reconfigure * relevant states of the nilfs object. */ memcpy(sbp[0], sbp[1], nilfs->ns_sbsize); nilfs->ns_crc_seed = le32_to_cpu(sbp[0]->s_crc_seed); nilfs->ns_sbwtime = le64_to_cpu(sbp[0]->s_wtime); /* verify consistency between two super blocks */ blocksize = BLOCK_SIZE << le32_to_cpu(sbp[0]->s_log_block_size); if (blocksize != nilfs->ns_blocksize) { nilfs_msg(sb, KERN_WARNING, "blocksize differs between two super blocks (%d != %d)", blocksize, nilfs->ns_blocksize); goto scan_error; } err = nilfs_store_log_cursor(nilfs, sbp[0]); if (err) goto scan_error; /* drop clean flag to allow roll-forward and recovery */ nilfs->ns_mount_state &= ~NILFS_VALID_FS; valid_fs = 0; err = nilfs_search_super_root(nilfs, &ri); if (err) goto scan_error; } err = nilfs_load_super_root(nilfs, sb, ri.ri_super_root); if (unlikely(err)) { nilfs_msg(sb, KERN_ERR, "error %d while loading super root", err); goto failed; } if (valid_fs) goto skip_recovery; if (s_flags & MS_RDONLY) { __u64 features; if (nilfs_test_opt(nilfs, NORECOVERY)) { nilfs_msg(sb, KERN_INFO, "norecovery option specified, skipping roll-forward recovery"); goto skip_recovery; } features = le64_to_cpu(nilfs->ns_sbp[0]->s_feature_compat_ro) & ~NILFS_FEATURE_COMPAT_RO_SUPP; if (features) { nilfs_msg(sb, KERN_ERR, "couldn't proceed with recovery because of unsupported optional features (%llx)", (unsigned long long)features); err = -EROFS; goto failed_unload; } if (really_read_only) { nilfs_msg(sb, KERN_ERR, "write access unavailable, cannot proceed"); err = -EROFS; goto failed_unload; } sb->s_flags &= ~MS_RDONLY; } else if (nilfs_test_opt(nilfs, NORECOVERY)) { nilfs_msg(sb, KERN_ERR, "recovery cancelled because norecovery option was specified for a read/write mount"); err = -EINVAL; goto failed_unload; } err = nilfs_salvage_orphan_logs(nilfs, sb, &ri); if (err) goto failed_unload; down_write(&nilfs->ns_sem); nilfs->ns_mount_state |= NILFS_VALID_FS; /* set "clean" flag */ err = nilfs_cleanup_super(sb); up_write(&nilfs->ns_sem); if (err) { nilfs_msg(sb, KERN_ERR, "error %d updating super block. recovery unfinished.", err); goto failed_unload; } nilfs_msg(sb, KERN_INFO, "recovery complete"); skip_recovery: nilfs_clear_recovery_info(&ri); sb->s_flags = s_flags; return 0; scan_error: nilfs_msg(sb, KERN_ERR, "error %d while searching super root", err); goto failed; failed_unload: iput(nilfs->ns_cpfile); iput(nilfs->ns_sufile); iput(nilfs->ns_dat); failed: nilfs_clear_recovery_info(&ri); sb->s_flags = s_flags; return err; } static unsigned long long nilfs_max_size(unsigned int blkbits) { unsigned int max_bits; unsigned long long res = MAX_LFS_FILESIZE; /* page cache limit */ max_bits = blkbits + NILFS_BMAP_KEY_BIT; /* bmap size limit */ if (max_bits < 64) res = min_t(unsigned long long, res, (1ULL << max_bits) - 1); return res; } /** * nilfs_nrsvsegs - calculate the number of reserved segments * @nilfs: nilfs object * @nsegs: total number of segments */ unsigned long nilfs_nrsvsegs(struct the_nilfs *nilfs, unsigned long nsegs) { return max_t(unsigned long, NILFS_MIN_NRSVSEGS, DIV_ROUND_UP(nsegs * nilfs->ns_r_segments_percentage, 100)); } void nilfs_set_nsegments(struct the_nilfs *nilfs, unsigned long nsegs) { nilfs->ns_nsegments = nsegs; nilfs->ns_nrsvsegs = nilfs_nrsvsegs(nilfs, nsegs); } static int nilfs_store_disk_layout(struct the_nilfs *nilfs, struct nilfs_super_block *sbp) { if (le32_to_cpu(sbp->s_rev_level) < NILFS_MIN_SUPP_REV) { nilfs_msg(nilfs->ns_sb, KERN_ERR, "unsupported revision (superblock rev.=%d.%d, current rev.=%d.%d). Please check the version of mkfs.nilfs(2).", le32_to_cpu(sbp->s_rev_level), le16_to_cpu(sbp->s_minor_rev_level), NILFS_CURRENT_REV, NILFS_MINOR_REV); return -EINVAL; } nilfs->ns_sbsize = le16_to_cpu(sbp->s_bytes); if (nilfs->ns_sbsize > BLOCK_SIZE) return -EINVAL; nilfs->ns_inode_size = le16_to_cpu(sbp->s_inode_size); if (nilfs->ns_inode_size > nilfs->ns_blocksize) { nilfs_msg(nilfs->ns_sb, KERN_ERR, "too large inode size: %d bytes", nilfs->ns_inode_size); return -EINVAL; } else if (nilfs->ns_inode_size < NILFS_MIN_INODE_SIZE) { nilfs_msg(nilfs->ns_sb, KERN_ERR, "too small inode size: %d bytes", nilfs->ns_inode_size); return -EINVAL; } nilfs->ns_first_ino = le32_to_cpu(sbp->s_first_ino); nilfs->ns_blocks_per_segment = le32_to_cpu(sbp->s_blocks_per_segment); if (nilfs->ns_blocks_per_segment < NILFS_SEG_MIN_BLOCKS) { nilfs_msg(nilfs->ns_sb, KERN_ERR, "too short segment: %lu blocks", nilfs->ns_blocks_per_segment); return -EINVAL; } nilfs->ns_first_data_block = le64_to_cpu(sbp->s_first_data_block); nilfs->ns_r_segments_percentage = le32_to_cpu(sbp->s_r_segments_percentage); if (nilfs->ns_r_segments_percentage < 1 || nilfs->ns_r_segments_percentage > 99) { nilfs_msg(nilfs->ns_sb, KERN_ERR, "invalid reserved segments percentage: %lu", nilfs->ns_r_segments_percentage); return -EINVAL; } nilfs_set_nsegments(nilfs, le64_to_cpu(sbp->s_nsegments)); nilfs->ns_crc_seed = le32_to_cpu(sbp->s_crc_seed); return 0; } static int nilfs_valid_sb(struct nilfs_super_block *sbp) { static unsigned char sum[4]; const int sumoff = offsetof(struct nilfs_super_block, s_sum); size_t bytes; u32 crc; if (!sbp || le16_to_cpu(sbp->s_magic) != NILFS_SUPER_MAGIC) return 0; bytes = le16_to_cpu(sbp->s_bytes); if (bytes < sumoff + 4 || bytes > BLOCK_SIZE) return 0; crc = crc32_le(le32_to_cpu(sbp->s_crc_seed), (unsigned char *)sbp, sumoff); crc = crc32_le(crc, sum, 4); crc = crc32_le(crc, (unsigned char *)sbp + sumoff + 4, bytes - sumoff - 4); return crc == le32_to_cpu(sbp->s_sum); } static int nilfs_sb2_bad_offset(struct nilfs_super_block *sbp, u64 offset) { return offset < ((le64_to_cpu(sbp->s_nsegments) * le32_to_cpu(sbp->s_blocks_per_segment)) << (le32_to_cpu(sbp->s_log_block_size) + 10)); } static void nilfs_release_super_block(struct the_nilfs *nilfs) { int i; for (i = 0; i < 2; i++) { if (nilfs->ns_sbp[i]) { brelse(nilfs->ns_sbh[i]); nilfs->ns_sbh[i] = NULL; nilfs->ns_sbp[i] = NULL; } } } void nilfs_fall_back_super_block(struct the_nilfs *nilfs) { brelse(nilfs->ns_sbh[0]); nilfs->ns_sbh[0] = nilfs->ns_sbh[1]; nilfs->ns_sbp[0] = nilfs->ns_sbp[1]; nilfs->ns_sbh[1] = NULL; nilfs->ns_sbp[1] = NULL; } void nilfs_swap_super_block(struct the_nilfs *nilfs) { struct buffer_head *tsbh = nilfs->ns_sbh[0]; struct nilfs_super_block *tsbp = nilfs->ns_sbp[0]; nilfs->ns_sbh[0] = nilfs->ns_sbh[1]; nilfs->ns_sbp[0] = nilfs->ns_sbp[1]; nilfs->ns_sbh[1] = tsbh; nilfs->ns_sbp[1] = tsbp; } static int nilfs_load_super_block(struct the_nilfs *nilfs, struct super_block *sb, int blocksize, struct nilfs_super_block **sbpp) { struct nilfs_super_block **sbp = nilfs->ns_sbp; struct buffer_head **sbh = nilfs->ns_sbh; u64 sb2off = NILFS_SB2_OFFSET_BYTES(nilfs->ns_bdev->bd_inode->i_size); int valid[2], swp = 0; sbp[0] = nilfs_read_super_block(sb, NILFS_SB_OFFSET_BYTES, blocksize, &sbh[0]); sbp[1] = nilfs_read_super_block(sb, sb2off, blocksize, &sbh[1]); if (!sbp[0]) { if (!sbp[1]) { nilfs_msg(sb, KERN_ERR, "unable to read superblock"); return -EIO; } nilfs_msg(sb, KERN_WARNING, "unable to read primary superblock (blocksize = %d)", blocksize); } else if (!sbp[1]) { nilfs_msg(sb, KERN_WARNING, "unable to read secondary superblock (blocksize = %d)", blocksize); } /* * Compare two super blocks and set 1 in swp if the secondary * super block is valid and newer. Otherwise, set 0 in swp. */ valid[0] = nilfs_valid_sb(sbp[0]); valid[1] = nilfs_valid_sb(sbp[1]); swp = valid[1] && (!valid[0] || le64_to_cpu(sbp[1]->s_last_cno) > le64_to_cpu(sbp[0]->s_last_cno)); if (valid[swp] && nilfs_sb2_bad_offset(sbp[swp], sb2off)) { brelse(sbh[1]); sbh[1] = NULL; sbp[1] = NULL; valid[1] = 0; swp = 0; } if (!valid[swp]) { nilfs_release_super_block(nilfs); nilfs_msg(sb, KERN_ERR, "couldn't find nilfs on the device"); return -EINVAL; } if (!valid[!swp]) nilfs_msg(sb, KERN_WARNING, "broken superblock, retrying with spare superblock (blocksize = %d)", blocksize); if (swp) nilfs_swap_super_block(nilfs); nilfs->ns_sbwcount = 0; nilfs->ns_sbwtime = le64_to_cpu(sbp[0]->s_wtime); nilfs->ns_prot_seq = le64_to_cpu(sbp[valid[1] & !swp]->s_last_seq); *sbpp = sbp[0]; return 0; } /** * init_nilfs - initialize a NILFS instance. * @nilfs: the_nilfs structure * @sb: super block * @data: mount options * * init_nilfs() performs common initialization per block device (e.g. * reading the super block, getting disk layout information, initializing * shared fields in the_nilfs). * * Return Value: On success, 0 is returned. On error, a negative error * code is returned. */ int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb, char *data) { struct nilfs_super_block *sbp; int blocksize; int err; down_write(&nilfs->ns_sem); blocksize = sb_min_blocksize(sb, NILFS_MIN_BLOCK_SIZE); if (!blocksize) { nilfs_msg(sb, KERN_ERR, "unable to set blocksize"); err = -EINVAL; goto out; } err = nilfs_load_super_block(nilfs, sb, blocksize, &sbp); if (err) goto out; err = nilfs_store_magic_and_option(sb, sbp, data); if (err) goto failed_sbh; err = nilfs_check_feature_compatibility(sb, sbp); if (err) goto failed_sbh; blocksize = BLOCK_SIZE << le32_to_cpu(sbp->s_log_block_size); if (blocksize < NILFS_MIN_BLOCK_SIZE || blocksize > NILFS_MAX_BLOCK_SIZE) { nilfs_msg(sb, KERN_ERR, "couldn't mount because of unsupported filesystem blocksize %d", blocksize); err = -EINVAL; goto failed_sbh; } if (sb->s_blocksize != blocksize) { int hw_blocksize = bdev_logical_block_size(sb->s_bdev); if (blocksize < hw_blocksize) { nilfs_msg(sb, KERN_ERR, "blocksize %d too small for device (sector-size = %d)", blocksize, hw_blocksize); err = -EINVAL; goto failed_sbh; } nilfs_release_super_block(nilfs); sb_set_blocksize(sb, blocksize); err = nilfs_load_super_block(nilfs, sb, blocksize, &sbp); if (err) goto out; /* * Not to failed_sbh; sbh is released automatically * when reloading fails. */ } nilfs->ns_blocksize_bits = sb->s_blocksize_bits; nilfs->ns_blocksize = blocksize; get_random_bytes(&nilfs->ns_next_generation, sizeof(nilfs->ns_next_generation)); err = nilfs_store_disk_layout(nilfs, sbp); if (err) goto failed_sbh; sb->s_maxbytes = nilfs_max_size(sb->s_blocksize_bits); nilfs->ns_mount_state = le16_to_cpu(sbp->s_state); err = nilfs_store_log_cursor(nilfs, sbp); if (err) goto failed_sbh; err = nilfs_sysfs_create_device_group(sb); if (err) goto failed_sbh; set_nilfs_init(nilfs); err = 0; out: up_write(&nilfs->ns_sem); return err; failed_sbh: nilfs_release_super_block(nilfs); goto out; } int nilfs_discard_segments(struct the_nilfs *nilfs, __u64 *segnump, size_t nsegs) { sector_t seg_start, seg_end; sector_t start = 0, nblocks = 0; unsigned int sects_per_block; __u64 *sn; int ret = 0; sects_per_block = (1 << nilfs->ns_blocksize_bits) / bdev_logical_block_size(nilfs->ns_bdev); for (sn = segnump; sn < segnump + nsegs; sn++) { nilfs_get_segment_range(nilfs, *sn, &seg_start, &seg_end); if (!nblocks) { start = seg_start; nblocks = seg_end - seg_start + 1; } else if (start + nblocks == seg_start) { nblocks += seg_end - seg_start + 1; } else { ret = blkdev_issue_discard(nilfs->ns_bdev, start * sects_per_block, nblocks * sects_per_block, GFP_NOFS, 0); if (ret < 0) return ret; nblocks = 0; } } if (nblocks) ret = blkdev_issue_discard(nilfs->ns_bdev, start * sects_per_block, nblocks * sects_per_block, GFP_NOFS, 0); return ret; } int nilfs_count_free_blocks(struct the_nilfs *nilfs, sector_t *nblocks) { unsigned long ncleansegs; down_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem); ncleansegs = nilfs_sufile_get_ncleansegs(nilfs->ns_sufile); up_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem); *nblocks = (sector_t)ncleansegs * nilfs->ns_blocks_per_segment; return 0; } int nilfs_near_disk_full(struct the_nilfs *nilfs) { unsigned long ncleansegs, nincsegs; ncleansegs = nilfs_sufile_get_ncleansegs(nilfs->ns_sufile); nincsegs = atomic_read(&nilfs->ns_ndirtyblks) / nilfs->ns_blocks_per_segment + 1; return ncleansegs <= nilfs->ns_nrsvsegs + nincsegs; } struct nilfs_root *nilfs_lookup_root(struct the_nilfs *nilfs, __u64 cno) { struct rb_node *n; struct nilfs_root *root; spin_lock(&nilfs->ns_cptree_lock); n = nilfs->ns_cptree.rb_node; while (n) { root = rb_entry(n, struct nilfs_root, rb_node); if (cno < root->cno) { n = n->rb_left; } else if (cno > root->cno) { n = n->rb_right; } else { atomic_inc(&root->count); spin_unlock(&nilfs->ns_cptree_lock); return root; } } spin_unlock(&nilfs->ns_cptree_lock); return NULL; } struct nilfs_root * nilfs_find_or_create_root(struct the_nilfs *nilfs, __u64 cno) { struct rb_node **p, *parent; struct nilfs_root *root, *new; int err; root = nilfs_lookup_root(nilfs, cno); if (root) return root; new = kzalloc(sizeof(*root), GFP_KERNEL); if (!new) return NULL; spin_lock(&nilfs->ns_cptree_lock); p = &nilfs->ns_cptree.rb_node; parent = NULL; while (*p) { parent = *p; root = rb_entry(parent, struct nilfs_root, rb_node); if (cno < root->cno) { p = &(*p)->rb_left; } else if (cno > root->cno) { p = &(*p)->rb_right; } else { atomic_inc(&root->count); spin_unlock(&nilfs->ns_cptree_lock); kfree(new); return root; } } new->cno = cno; new->ifile = NULL; new->nilfs = nilfs; atomic_set(&new->count, 1); atomic64_set(&new->inodes_count, 0); atomic64_set(&new->blocks_count, 0); rb_link_node(&new->rb_node, parent, p); rb_insert_color(&new->rb_node, &nilfs->ns_cptree); spin_unlock(&nilfs->ns_cptree_lock); err = nilfs_sysfs_create_snapshot_group(new); if (err) { kfree(new); new = NULL; } return new; } void nilfs_put_root(struct nilfs_root *root) { if (atomic_dec_and_test(&root->count)) { struct the_nilfs *nilfs = root->nilfs; nilfs_sysfs_delete_snapshot_group(root); spin_lock(&nilfs->ns_cptree_lock); rb_erase(&root->rb_node, &nilfs->ns_cptree); spin_unlock(&nilfs->ns_cptree_lock); iput(root->ifile); kfree(root); } }