/* * cpfile.c - NILFS checkpoint file. * * Copyright (C) 2006-2008 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 Koji Sato <koji@osrg.net>. */ #include <linux/kernel.h> #include <linux/fs.h> #include <linux/string.h> #include <linux/buffer_head.h> #include <linux/errno.h> #include <linux/nilfs2_fs.h> #include "mdt.h" #include "cpfile.h" static inline unsigned long nilfs_cpfile_checkpoints_per_block(const struct inode *cpfile) { return NILFS_MDT(cpfile)->mi_entries_per_block; } /* block number from the beginning of the file */ static unsigned long nilfs_cpfile_get_blkoff(const struct inode *cpfile, __u64 cno) { __u64 tcno = cno + NILFS_MDT(cpfile)->mi_first_entry_offset - 1; do_div(tcno, nilfs_cpfile_checkpoints_per_block(cpfile)); return (unsigned long)tcno; } /* offset in block */ static unsigned long nilfs_cpfile_get_offset(const struct inode *cpfile, __u64 cno) { __u64 tcno = cno + NILFS_MDT(cpfile)->mi_first_entry_offset - 1; return do_div(tcno, nilfs_cpfile_checkpoints_per_block(cpfile)); } static unsigned long nilfs_cpfile_checkpoints_in_block(const struct inode *cpfile, __u64 curr, __u64 max) { return min_t(__u64, nilfs_cpfile_checkpoints_per_block(cpfile) - nilfs_cpfile_get_offset(cpfile, curr), max - curr); } static inline int nilfs_cpfile_is_in_first(const struct inode *cpfile, __u64 cno) { return nilfs_cpfile_get_blkoff(cpfile, cno) == 0; } static unsigned int nilfs_cpfile_block_add_valid_checkpoints(const struct inode *cpfile, struct buffer_head *bh, void *kaddr, unsigned int n) { struct nilfs_checkpoint *cp = kaddr + bh_offset(bh); unsigned int count; count = le32_to_cpu(cp->cp_checkpoints_count) + n; cp->cp_checkpoints_count = cpu_to_le32(count); return count; } static unsigned int nilfs_cpfile_block_sub_valid_checkpoints(const struct inode *cpfile, struct buffer_head *bh, void *kaddr, unsigned int n) { struct nilfs_checkpoint *cp = kaddr + bh_offset(bh); unsigned int count; WARN_ON(le32_to_cpu(cp->cp_checkpoints_count) < n); count = le32_to_cpu(cp->cp_checkpoints_count) - n; cp->cp_checkpoints_count = cpu_to_le32(count); return count; } static inline struct nilfs_cpfile_header * nilfs_cpfile_block_get_header(const struct inode *cpfile, struct buffer_head *bh, void *kaddr) { return kaddr + bh_offset(bh); } static struct nilfs_checkpoint * nilfs_cpfile_block_get_checkpoint(const struct inode *cpfile, __u64 cno, struct buffer_head *bh, void *kaddr) { return kaddr + bh_offset(bh) + nilfs_cpfile_get_offset(cpfile, cno) * NILFS_MDT(cpfile)->mi_entry_size; } static void nilfs_cpfile_block_init(struct inode *cpfile, struct buffer_head *bh, void *kaddr) { struct nilfs_checkpoint *cp = kaddr + bh_offset(bh); size_t cpsz = NILFS_MDT(cpfile)->mi_entry_size; int n = nilfs_cpfile_checkpoints_per_block(cpfile); while (n-- > 0) { nilfs_checkpoint_set_invalid(cp); cp = (void *)cp + cpsz; } } static inline int nilfs_cpfile_get_header_block(struct inode *cpfile, struct buffer_head **bhp) { return nilfs_mdt_get_block(cpfile, 0, 0, NULL, bhp); } static inline int nilfs_cpfile_get_checkpoint_block(struct inode *cpfile, __u64 cno, int create, struct buffer_head **bhp) { return nilfs_mdt_get_block(cpfile, nilfs_cpfile_get_blkoff(cpfile, cno), create, nilfs_cpfile_block_init, bhp); } static inline int nilfs_cpfile_delete_checkpoint_block(struct inode *cpfile, __u64 cno) { return nilfs_mdt_delete_block(cpfile, nilfs_cpfile_get_blkoff(cpfile, cno)); } /** * nilfs_cpfile_get_checkpoint - get a checkpoint * @cpfile: inode of checkpoint file * @cno: checkpoint number * @create: create flag * @cpp: pointer to a checkpoint * @bhp: pointer to a buffer head * * Description: nilfs_cpfile_get_checkpoint() acquires the checkpoint * specified by @cno. A new checkpoint will be created if @cno is the current * checkpoint number and @create is nonzero. * * Return Value: On success, 0 is returned, and the checkpoint and the * buffer head of the buffer on which the checkpoint is located are stored in * the place pointed by @cpp and @bhp, respectively. On error, one of the * following negative error codes is returned. * * %-EIO - I/O error. * * %-ENOMEM - Insufficient amount of memory available. * * %-ENOENT - No such checkpoint. * * %-EINVAL - invalid checkpoint. */ int nilfs_cpfile_get_checkpoint(struct inode *cpfile, __u64 cno, int create, struct nilfs_checkpoint **cpp, struct buffer_head **bhp) { struct buffer_head *header_bh, *cp_bh; struct nilfs_cpfile_header *header; struct nilfs_checkpoint *cp; void *kaddr; int ret; if (unlikely(cno < 1 || cno > nilfs_mdt_cno(cpfile) || (cno < nilfs_mdt_cno(cpfile) && create))) return -EINVAL; down_write(&NILFS_MDT(cpfile)->mi_sem); ret = nilfs_cpfile_get_header_block(cpfile, &header_bh); if (ret < 0) goto out_sem; ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, create, &cp_bh); if (ret < 0) goto out_header; kaddr = kmap(cp_bh->b_page); cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr); if (nilfs_checkpoint_invalid(cp)) { if (!create) { kunmap(cp_bh->b_page); brelse(cp_bh); ret = -ENOENT; goto out_header; } /* a newly-created checkpoint */ nilfs_checkpoint_clear_invalid(cp); if (!nilfs_cpfile_is_in_first(cpfile, cno)) nilfs_cpfile_block_add_valid_checkpoints(cpfile, cp_bh, kaddr, 1); nilfs_mdt_mark_buffer_dirty(cp_bh); kaddr = kmap_atomic(header_bh->b_page, KM_USER0); header = nilfs_cpfile_block_get_header(cpfile, header_bh, kaddr); le64_add_cpu(&header->ch_ncheckpoints, 1); kunmap_atomic(kaddr, KM_USER0); nilfs_mdt_mark_buffer_dirty(header_bh); nilfs_mdt_mark_dirty(cpfile); } if (cpp != NULL) *cpp = cp; *bhp = cp_bh; out_header: brelse(header_bh); out_sem: up_write(&NILFS_MDT(cpfile)->mi_sem); return ret; } /** * nilfs_cpfile_put_checkpoint - put a checkpoint * @cpfile: inode of checkpoint file * @cno: checkpoint number * @bh: buffer head * * Description: nilfs_cpfile_put_checkpoint() releases the checkpoint * specified by @cno. @bh must be the buffer head which has been returned by * a previous call to nilfs_cpfile_get_checkpoint() with @cno. */ void nilfs_cpfile_put_checkpoint(struct inode *cpfile, __u64 cno, struct buffer_head *bh) { kunmap(bh->b_page); brelse(bh); } /** * nilfs_cpfile_delete_checkpoints - delete checkpoints * @cpfile: inode of checkpoint file * @start: start checkpoint number * @end: end checkpoint numer * * Description: nilfs_cpfile_delete_checkpoints() deletes the checkpoints in * the period from @start to @end, excluding @end itself. The checkpoints * which have been already deleted are ignored. * * Return Value: On success, 0 is returned. On error, one of the following * negative error codes is returned. * * %-EIO - I/O error. * * %-ENOMEM - Insufficient amount of memory available. * * %-EINVAL - invalid checkpoints. */ int nilfs_cpfile_delete_checkpoints(struct inode *cpfile, __u64 start, __u64 end) { struct buffer_head *header_bh, *cp_bh; struct nilfs_cpfile_header *header; struct nilfs_checkpoint *cp; size_t cpsz = NILFS_MDT(cpfile)->mi_entry_size; __u64 cno; void *kaddr; unsigned long tnicps; int ret, ncps, nicps, count, i; if (unlikely(start == 0 || start > end)) { printk(KERN_ERR "%s: invalid range of checkpoint numbers: " "[%llu, %llu)\n", __func__, (unsigned long long)start, (unsigned long long)end); return -EINVAL; } down_write(&NILFS_MDT(cpfile)->mi_sem); ret = nilfs_cpfile_get_header_block(cpfile, &header_bh); if (ret < 0) goto out_sem; tnicps = 0; for (cno = start; cno < end; cno += ncps) { ncps = nilfs_cpfile_checkpoints_in_block(cpfile, cno, end); ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh); if (ret < 0) { if (ret != -ENOENT) break; /* skip hole */ ret = 0; continue; } kaddr = kmap_atomic(cp_bh->b_page, KM_USER0); cp = nilfs_cpfile_block_get_checkpoint( cpfile, cno, cp_bh, kaddr); nicps = 0; for (i = 0; i < ncps; i++, cp = (void *)cp + cpsz) { WARN_ON(nilfs_checkpoint_snapshot(cp)); if (!nilfs_checkpoint_invalid(cp)) { nilfs_checkpoint_set_invalid(cp); nicps++; } } if (nicps > 0) { tnicps += nicps; nilfs_mdt_mark_buffer_dirty(cp_bh); nilfs_mdt_mark_dirty(cpfile); if (!nilfs_cpfile_is_in_first(cpfile, cno) && (count = nilfs_cpfile_block_sub_valid_checkpoints( cpfile, cp_bh, kaddr, nicps)) == 0) { /* make hole */ kunmap_atomic(kaddr, KM_USER0); brelse(cp_bh); ret = nilfs_cpfile_delete_checkpoint_block( cpfile, cno); if (ret == 0) continue; printk(KERN_ERR "%s: cannot delete block\n", __func__); break; } } kunmap_atomic(kaddr, KM_USER0); brelse(cp_bh); } if (tnicps > 0) { kaddr = kmap_atomic(header_bh->b_page, KM_USER0); header = nilfs_cpfile_block_get_header(cpfile, header_bh, kaddr); le64_add_cpu(&header->ch_ncheckpoints, -(u64)tnicps); nilfs_mdt_mark_buffer_dirty(header_bh); nilfs_mdt_mark_dirty(cpfile); kunmap_atomic(kaddr, KM_USER0); } brelse(header_bh); out_sem: up_write(&NILFS_MDT(cpfile)->mi_sem); return ret; } static void nilfs_cpfile_checkpoint_to_cpinfo(struct inode *cpfile, struct nilfs_checkpoint *cp, struct nilfs_cpinfo *ci) { ci->ci_flags = le32_to_cpu(cp->cp_flags); ci->ci_cno = le64_to_cpu(cp->cp_cno); ci->ci_create = le64_to_cpu(cp->cp_create); ci->ci_nblk_inc = le64_to_cpu(cp->cp_nblk_inc); ci->ci_inodes_count = le64_to_cpu(cp->cp_inodes_count); ci->ci_blocks_count = le64_to_cpu(cp->cp_blocks_count); ci->ci_next = le64_to_cpu(cp->cp_snapshot_list.ssl_next); } static ssize_t nilfs_cpfile_do_get_cpinfo(struct inode *cpfile, __u64 *cnop, void *buf, unsigned cisz, size_t nci) { struct nilfs_checkpoint *cp; struct nilfs_cpinfo *ci = buf; struct buffer_head *bh; size_t cpsz = NILFS_MDT(cpfile)->mi_entry_size; __u64 cur_cno = nilfs_mdt_cno(cpfile), cno = *cnop; void *kaddr; int n, ret; int ncps, i; if (cno == 0) return -ENOENT; /* checkpoint number 0 is invalid */ down_read(&NILFS_MDT(cpfile)->mi_sem); for (n = 0; cno < cur_cno && n < nci; cno += ncps) { ncps = nilfs_cpfile_checkpoints_in_block(cpfile, cno, cur_cno); ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &bh); if (ret < 0) { if (ret != -ENOENT) goto out; continue; /* skip hole */ } kaddr = kmap_atomic(bh->b_page, KM_USER0); cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr); for (i = 0; i < ncps && n < nci; i++, cp = (void *)cp + cpsz) { if (!nilfs_checkpoint_invalid(cp)) { nilfs_cpfile_checkpoint_to_cpinfo(cpfile, cp, ci); ci = (void *)ci + cisz; n++; } } kunmap_atomic(kaddr, KM_USER0); brelse(bh); } ret = n; if (n > 0) { ci = (void *)ci - cisz; *cnop = ci->ci_cno + 1; } out: up_read(&NILFS_MDT(cpfile)->mi_sem); return ret; } static ssize_t nilfs_cpfile_do_get_ssinfo(struct inode *cpfile, __u64 *cnop, void *buf, unsigned cisz, size_t nci) { struct buffer_head *bh; struct nilfs_cpfile_header *header; struct nilfs_checkpoint *cp; struct nilfs_cpinfo *ci = buf; __u64 curr = *cnop, next; unsigned long curr_blkoff, next_blkoff; void *kaddr; int n = 0, ret; down_read(&NILFS_MDT(cpfile)->mi_sem); if (curr == 0) { ret = nilfs_cpfile_get_header_block(cpfile, &bh); if (ret < 0) goto out; kaddr = kmap_atomic(bh->b_page, KM_USER0); header = nilfs_cpfile_block_get_header(cpfile, bh, kaddr); curr = le64_to_cpu(header->ch_snapshot_list.ssl_next); kunmap_atomic(kaddr, KM_USER0); brelse(bh); if (curr == 0) { ret = 0; goto out; } } else if (unlikely(curr == ~(__u64)0)) { ret = 0; goto out; } curr_blkoff = nilfs_cpfile_get_blkoff(cpfile, curr); ret = nilfs_cpfile_get_checkpoint_block(cpfile, curr, 0, &bh); if (unlikely(ret < 0)) { if (ret == -ENOENT) ret = 0; /* No snapshots (started from a hole block) */ goto out; } kaddr = kmap_atomic(bh->b_page, KM_USER0); while (n < nci) { cp = nilfs_cpfile_block_get_checkpoint(cpfile, curr, bh, kaddr); curr = ~(__u64)0; /* Terminator */ if (unlikely(nilfs_checkpoint_invalid(cp) || !nilfs_checkpoint_snapshot(cp))) break; nilfs_cpfile_checkpoint_to_cpinfo(cpfile, cp, ci); ci = (void *)ci + cisz; n++; next = le64_to_cpu(cp->cp_snapshot_list.ssl_next); if (next == 0) break; /* reach end of the snapshot list */ next_blkoff = nilfs_cpfile_get_blkoff(cpfile, next); if (curr_blkoff != next_blkoff) { kunmap_atomic(kaddr, KM_USER0); brelse(bh); ret = nilfs_cpfile_get_checkpoint_block(cpfile, next, 0, &bh); if (unlikely(ret < 0)) { WARN_ON(ret == -ENOENT); goto out; } kaddr = kmap_atomic(bh->b_page, KM_USER0); } curr = next; curr_blkoff = next_blkoff; } kunmap_atomic(kaddr, KM_USER0); brelse(bh); *cnop = curr; ret = n; out: up_read(&NILFS_MDT(cpfile)->mi_sem); return ret; } /** * nilfs_cpfile_get_cpinfo - * @cpfile: * @cno: * @ci: * @nci: */ ssize_t nilfs_cpfile_get_cpinfo(struct inode *cpfile, __u64 *cnop, int mode, void *buf, unsigned cisz, size_t nci) { switch (mode) { case NILFS_CHECKPOINT: return nilfs_cpfile_do_get_cpinfo(cpfile, cnop, buf, cisz, nci); case NILFS_SNAPSHOT: return nilfs_cpfile_do_get_ssinfo(cpfile, cnop, buf, cisz, nci); default: return -EINVAL; } } /** * nilfs_cpfile_delete_checkpoint - * @cpfile: * @cno: */ int nilfs_cpfile_delete_checkpoint(struct inode *cpfile, __u64 cno) { struct nilfs_cpinfo ci; __u64 tcno = cno; ssize_t nci; nci = nilfs_cpfile_do_get_cpinfo(cpfile, &tcno, &ci, sizeof(ci), 1); if (nci < 0) return nci; else if (nci == 0 || ci.ci_cno != cno) return -ENOENT; else if (nilfs_cpinfo_snapshot(&ci)) return -EBUSY; return nilfs_cpfile_delete_checkpoints(cpfile, cno, cno + 1); } static struct nilfs_snapshot_list * nilfs_cpfile_block_get_snapshot_list(const struct inode *cpfile, __u64 cno, struct buffer_head *bh, void *kaddr) { struct nilfs_cpfile_header *header; struct nilfs_checkpoint *cp; struct nilfs_snapshot_list *list; if (cno != 0) { cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr); list = &cp->cp_snapshot_list; } else { header = nilfs_cpfile_block_get_header(cpfile, bh, kaddr); list = &header->ch_snapshot_list; } return list; } static int nilfs_cpfile_set_snapshot(struct inode *cpfile, __u64 cno) { struct buffer_head *header_bh, *curr_bh, *prev_bh, *cp_bh; struct nilfs_cpfile_header *header; struct nilfs_checkpoint *cp; struct nilfs_snapshot_list *list; __u64 curr, prev; unsigned long curr_blkoff, prev_blkoff; void *kaddr; int ret; if (cno == 0) return -ENOENT; /* checkpoint number 0 is invalid */ down_write(&NILFS_MDT(cpfile)->mi_sem); ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh); if (ret < 0) goto out_sem; kaddr = kmap_atomic(cp_bh->b_page, KM_USER0); cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr); if (nilfs_checkpoint_invalid(cp)) { ret = -ENOENT; kunmap_atomic(kaddr, KM_USER0); goto out_cp; } if (nilfs_checkpoint_snapshot(cp)) { ret = 0; kunmap_atomic(kaddr, KM_USER0); goto out_cp; } kunmap_atomic(kaddr, KM_USER0); ret = nilfs_cpfile_get_header_block(cpfile, &header_bh); if (ret < 0) goto out_cp; kaddr = kmap_atomic(header_bh->b_page, KM_USER0); header = nilfs_cpfile_block_get_header(cpfile, header_bh, kaddr); list = &header->ch_snapshot_list; curr_bh = header_bh; get_bh(curr_bh); curr = 0; curr_blkoff = 0; prev = le64_to_cpu(list->ssl_prev); while (prev > cno) { prev_blkoff = nilfs_cpfile_get_blkoff(cpfile, prev); curr = prev; if (curr_blkoff != prev_blkoff) { kunmap_atomic(kaddr, KM_USER0); brelse(curr_bh); ret = nilfs_cpfile_get_checkpoint_block(cpfile, curr, 0, &curr_bh); if (ret < 0) goto out_header; kaddr = kmap_atomic(curr_bh->b_page, KM_USER0); } curr_blkoff = prev_blkoff; cp = nilfs_cpfile_block_get_checkpoint( cpfile, curr, curr_bh, kaddr); list = &cp->cp_snapshot_list; prev = le64_to_cpu(list->ssl_prev); } kunmap_atomic(kaddr, KM_USER0); if (prev != 0) { ret = nilfs_cpfile_get_checkpoint_block(cpfile, prev, 0, &prev_bh); if (ret < 0) goto out_curr; } else { prev_bh = header_bh; get_bh(prev_bh); } kaddr = kmap_atomic(curr_bh->b_page, KM_USER0); list = nilfs_cpfile_block_get_snapshot_list( cpfile, curr, curr_bh, kaddr); list->ssl_prev = cpu_to_le64(cno); kunmap_atomic(kaddr, KM_USER0); kaddr = kmap_atomic(cp_bh->b_page, KM_USER0); cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr); cp->cp_snapshot_list.ssl_next = cpu_to_le64(curr); cp->cp_snapshot_list.ssl_prev = cpu_to_le64(prev); nilfs_checkpoint_set_snapshot(cp); kunmap_atomic(kaddr, KM_USER0); kaddr = kmap_atomic(prev_bh->b_page, KM_USER0); list = nilfs_cpfile_block_get_snapshot_list( cpfile, prev, prev_bh, kaddr); list->ssl_next = cpu_to_le64(cno); kunmap_atomic(kaddr, KM_USER0); kaddr = kmap_atomic(header_bh->b_page, KM_USER0); header = nilfs_cpfile_block_get_header(cpfile, header_bh, kaddr); le64_add_cpu(&header->ch_nsnapshots, 1); kunmap_atomic(kaddr, KM_USER0); nilfs_mdt_mark_buffer_dirty(prev_bh); nilfs_mdt_mark_buffer_dirty(curr_bh); nilfs_mdt_mark_buffer_dirty(cp_bh); nilfs_mdt_mark_buffer_dirty(header_bh); nilfs_mdt_mark_dirty(cpfile); brelse(prev_bh); out_curr: brelse(curr_bh); out_header: brelse(header_bh); out_cp: brelse(cp_bh); out_sem: up_write(&NILFS_MDT(cpfile)->mi_sem); return ret; } static int nilfs_cpfile_clear_snapshot(struct inode *cpfile, __u64 cno) { struct buffer_head *header_bh, *next_bh, *prev_bh, *cp_bh; struct nilfs_cpfile_header *header; struct nilfs_checkpoint *cp; struct nilfs_snapshot_list *list; __u64 next, prev; void *kaddr; int ret; if (cno == 0) return -ENOENT; /* checkpoint number 0 is invalid */ down_write(&NILFS_MDT(cpfile)->mi_sem); ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh); if (ret < 0) goto out_sem; kaddr = kmap_atomic(cp_bh->b_page, KM_USER0); cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr); if (nilfs_checkpoint_invalid(cp)) { ret = -ENOENT; kunmap_atomic(kaddr, KM_USER0); goto out_cp; } if (!nilfs_checkpoint_snapshot(cp)) { ret = 0; kunmap_atomic(kaddr, KM_USER0); goto out_cp; } list = &cp->cp_snapshot_list; next = le64_to_cpu(list->ssl_next); prev = le64_to_cpu(list->ssl_prev); kunmap_atomic(kaddr, KM_USER0); ret = nilfs_cpfile_get_header_block(cpfile, &header_bh); if (ret < 0) goto out_cp; if (next != 0) { ret = nilfs_cpfile_get_checkpoint_block(cpfile, next, 0, &next_bh); if (ret < 0) goto out_header; } else { next_bh = header_bh; get_bh(next_bh); } if (prev != 0) { ret = nilfs_cpfile_get_checkpoint_block(cpfile, prev, 0, &prev_bh); if (ret < 0) goto out_next; } else { prev_bh = header_bh; get_bh(prev_bh); } kaddr = kmap_atomic(next_bh->b_page, KM_USER0); list = nilfs_cpfile_block_get_snapshot_list( cpfile, next, next_bh, kaddr); list->ssl_prev = cpu_to_le64(prev); kunmap_atomic(kaddr, KM_USER0); kaddr = kmap_atomic(prev_bh->b_page, KM_USER0); list = nilfs_cpfile_block_get_snapshot_list( cpfile, prev, prev_bh, kaddr); list->ssl_next = cpu_to_le64(next); kunmap_atomic(kaddr, KM_USER0); kaddr = kmap_atomic(cp_bh->b_page, KM_USER0); cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr); cp->cp_snapshot_list.ssl_next = cpu_to_le64(0); cp->cp_snapshot_list.ssl_prev = cpu_to_le64(0); nilfs_checkpoint_clear_snapshot(cp); kunmap_atomic(kaddr, KM_USER0); kaddr = kmap_atomic(header_bh->b_page, KM_USER0); header = nilfs_cpfile_block_get_header(cpfile, header_bh, kaddr); le64_add_cpu(&header->ch_nsnapshots, -1); kunmap_atomic(kaddr, KM_USER0); nilfs_mdt_mark_buffer_dirty(next_bh); nilfs_mdt_mark_buffer_dirty(prev_bh); nilfs_mdt_mark_buffer_dirty(cp_bh); nilfs_mdt_mark_buffer_dirty(header_bh); nilfs_mdt_mark_dirty(cpfile); brelse(prev_bh); out_next: brelse(next_bh); out_header: brelse(header_bh); out_cp: brelse(cp_bh); out_sem: up_write(&NILFS_MDT(cpfile)->mi_sem); return ret; } /** * nilfs_cpfile_is_snapshot - * @cpfile: inode of checkpoint file * @cno: checkpoint number * * Description: * * Return Value: On success, 1 is returned if the checkpoint specified by * @cno is a snapshot, or 0 if not. On error, one of the following negative * error codes is returned. * * %-EIO - I/O error. * * %-ENOMEM - Insufficient amount of memory available. * * %-ENOENT - No such checkpoint. */ int nilfs_cpfile_is_snapshot(struct inode *cpfile, __u64 cno) { struct buffer_head *bh; struct nilfs_checkpoint *cp; void *kaddr; int ret; /* CP number is invalid if it's zero or larger than the largest exist one.*/ if (cno == 0 || cno >= nilfs_mdt_cno(cpfile)) return -ENOENT; down_read(&NILFS_MDT(cpfile)->mi_sem); ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &bh); if (ret < 0) goto out; kaddr = kmap_atomic(bh->b_page, KM_USER0); cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr); if (nilfs_checkpoint_invalid(cp)) ret = -ENOENT; else ret = nilfs_checkpoint_snapshot(cp); kunmap_atomic(kaddr, KM_USER0); brelse(bh); out: up_read(&NILFS_MDT(cpfile)->mi_sem); return ret; } /** * nilfs_cpfile_change_cpmode - change checkpoint mode * @cpfile: inode of checkpoint file * @cno: checkpoint number * @status: mode of checkpoint * * Description: nilfs_change_cpmode() changes the mode of the checkpoint * specified by @cno. The mode @mode is NILFS_CHECKPOINT or NILFS_SNAPSHOT. * * Return Value: On success, 0 is returned. On error, one of the following * negative error codes is returned. * * %-EIO - I/O error. * * %-ENOMEM - Insufficient amount of memory available. * * %-ENOENT - No such checkpoint. */ int nilfs_cpfile_change_cpmode(struct inode *cpfile, __u64 cno, int mode) { struct the_nilfs *nilfs; int ret; nilfs = NILFS_MDT(cpfile)->mi_nilfs; switch (mode) { case NILFS_CHECKPOINT: /* * Check for protecting existing snapshot mounts: * ns_mount_mutex is used to make this operation atomic and * exclusive with a new mount job. Though it doesn't cover * umount, it's enough for the purpose. */ mutex_lock(&nilfs->ns_mount_mutex); if (nilfs_checkpoint_is_mounted(nilfs, cno, 1)) { /* Current implementation does not have to protect plain read-only mounts since they are exclusive with a read/write mount and are protected from the cleaner. */ ret = -EBUSY; } else ret = nilfs_cpfile_clear_snapshot(cpfile, cno); mutex_unlock(&nilfs->ns_mount_mutex); return ret; case NILFS_SNAPSHOT: return nilfs_cpfile_set_snapshot(cpfile, cno); default: return -EINVAL; } } /** * nilfs_cpfile_get_stat - get checkpoint statistics * @cpfile: inode of checkpoint file * @stat: pointer to a structure of checkpoint statistics * * Description: nilfs_cpfile_get_stat() returns information about checkpoints. * * Return Value: On success, 0 is returned, and checkpoints information is * stored in the place pointed by @stat. On error, one of the following * negative error codes is returned. * * %-EIO - I/O error. * * %-ENOMEM - Insufficient amount of memory available. */ int nilfs_cpfile_get_stat(struct inode *cpfile, struct nilfs_cpstat *cpstat) { struct buffer_head *bh; struct nilfs_cpfile_header *header; void *kaddr; int ret; down_read(&NILFS_MDT(cpfile)->mi_sem); ret = nilfs_cpfile_get_header_block(cpfile, &bh); if (ret < 0) goto out_sem; kaddr = kmap_atomic(bh->b_page, KM_USER0); header = nilfs_cpfile_block_get_header(cpfile, bh, kaddr); cpstat->cs_cno = nilfs_mdt_cno(cpfile); cpstat->cs_ncps = le64_to_cpu(header->ch_ncheckpoints); cpstat->cs_nsss = le64_to_cpu(header->ch_nsnapshots); kunmap_atomic(kaddr, KM_USER0); brelse(bh); out_sem: up_read(&NILFS_MDT(cpfile)->mi_sem); return ret; }