diff options
Diffstat (limited to 'fs/nilfs2/the_nilfs.c')
| -rw-r--r-- | fs/nilfs2/the_nilfs.c | 815 |
1 files changed, 815 insertions, 0 deletions
diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c new file mode 100644 index 000000000..69bd801af --- /dev/null +++ b/fs/nilfs2/the_nilfs.c @@ -0,0 +1,815 @@ +/* + * 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. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + * + * Written by Ryusuke Konishi <ryusuke@osrg.net> + * + */ + +#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 + * @bdev: block device to which the_nilfs is related + * + * Return Value: On success, pointer to the_nilfs is returned. + * On error, NULL is returned. + */ +struct the_nilfs *alloc_nilfs(struct block_device *bdev) +{ + struct the_nilfs *nilfs; + + nilfs = kzalloc(sizeof(*nilfs), GFP_KERNEL); + if (!nilfs) + return NULL; + + nilfs->ns_bdev = 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 dat_entry_size, segment_usage_size, checkpoint_size; + unsigned 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) { + printk(KERN_ERR "NILFS invalid last segment number.\n"); + 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) { + printk(KERN_WARNING "NILFS warning: mounting unchecked fs\n"); + if (s_flags & MS_RDONLY) { + printk(KERN_INFO "NILFS: INFO: recovery " + "required for readonly filesystem.\n"); + printk(KERN_INFO "NILFS: write access will " + "be enabled during recovery.\n"); + } + } + + 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])) { + printk(KERN_WARNING + "NILFS warning: unable to fall back to spare" + "super block\n"); + goto scan_error; + } + printk(KERN_INFO + "NILFS: try rollback from an earlier position\n"); + + /* + * 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) { + printk(KERN_WARNING + "NILFS warning: blocksize differs between " + "two super blocks (%d != %d)\n", + 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)) { + printk(KERN_ERR "NILFS: error loading super root.\n"); + goto failed; + } + + if (valid_fs) + goto skip_recovery; + + if (s_flags & MS_RDONLY) { + __u64 features; + + if (nilfs_test_opt(nilfs, NORECOVERY)) { + printk(KERN_INFO "NILFS: norecovery option specified. " + "skipping roll-forward recovery\n"); + goto skip_recovery; + } + features = le64_to_cpu(nilfs->ns_sbp[0]->s_feature_compat_ro) & + ~NILFS_FEATURE_COMPAT_RO_SUPP; + if (features) { + printk(KERN_ERR "NILFS: couldn't proceed with " + "recovery because of unsupported optional " + "features (%llx)\n", + (unsigned long long)features); + err = -EROFS; + goto failed_unload; + } + if (really_read_only) { + printk(KERN_ERR "NILFS: write access " + "unavailable, cannot proceed.\n"); + err = -EROFS; + goto failed_unload; + } + sb->s_flags &= ~MS_RDONLY; + } else if (nilfs_test_opt(nilfs, NORECOVERY)) { + printk(KERN_ERR "NILFS: recovery cancelled because norecovery " + "option was specified for a read/write mount\n"); + 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) { + printk(KERN_ERR "NILFS: failed to update super block. " + "recovery unfinished.\n"); + goto failed_unload; + } + printk(KERN_INFO "NILFS: recovery complete.\n"); + + skip_recovery: + nilfs_clear_recovery_info(&ri); + sb->s_flags = s_flags; + return 0; + + scan_error: + printk(KERN_ERR "NILFS: error searching super root.\n"); + 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) { + printk(KERN_ERR "NILFS: unsupported revision " + "(superblock rev.=%d.%d, current rev.=%d.%d). " + "Please check the version of mkfs.nilfs.\n", + 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) { + printk(KERN_ERR "NILFS: too large inode size: %d bytes.\n", + nilfs->ns_inode_size); + return -EINVAL; + } else if (nilfs->ns_inode_size < NILFS_MIN_INODE_SIZE) { + printk(KERN_ERR "NILFS: too small inode size: %d bytes.\n", + 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) { + printk(KERN_ERR "NILFS: too short segment.\n"); + 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) { + printk(KERN_ERR "NILFS: invalid reserved segments percentage.\n"); + 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 > 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]) { + printk(KERN_ERR "NILFS: unable to read superblock\n"); + return -EIO; + } + printk(KERN_WARNING + "NILFS warning: unable to read primary superblock " + "(blocksize = %d)\n", blocksize); + } else if (!sbp[1]) { + printk(KERN_WARNING + "NILFS warning: unable to read secondary superblock " + "(blocksize = %d)\n", 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); + printk(KERN_ERR "NILFS: Can't find nilfs on dev %s.\n", + sb->s_id); + return -EINVAL; + } + + if (!valid[!swp]) + printk(KERN_WARNING "NILFS warning: broken superblock. " + "using spare superblock (blocksize = %d).\n", 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) { + printk(KERN_ERR "NILFS: unable to set blocksize\n"); + 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) { + printk(KERN_ERR "NILFS: couldn't mount because of unsupported " + "filesystem blocksize %d\n", 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) { + printk(KERN_ERR + "NILFS: blocksize %d too small for device " + "(sector-size = %d).\n", + 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 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); + } +} |