diff options
Diffstat (limited to 'fs/nilfs2/cpfile.c')
| -rw-r--r-- | fs/nilfs2/cpfile.c | 925 |
1 files changed, 925 insertions, 0 deletions
diff --git a/fs/nilfs2/cpfile.c b/fs/nilfs2/cpfile.c new file mode 100644 index 00000000000..e90b60dfced --- /dev/null +++ b/fs/nilfs2/cpfile.c @@ -0,0 +1,925 @@ +/* + * 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; + } + + /* cannot delete the latest checkpoint */ + if (start == nilfs_mdt_cno(cpfile) - 1) + return -EPERM; + + 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) + goto out_sem; + /* 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__); + goto out_sem; + } + } + + 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, + struct nilfs_cpinfo *ci, size_t nci) +{ + struct nilfs_checkpoint *cp; + 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[n++]); + } + kunmap_atomic(kaddr, KM_USER0); + brelse(bh); + } + + ret = n; + if (n > 0) + *cnop = ci[n - 1].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, + struct nilfs_cpinfo *ci, size_t nci) +{ + struct buffer_head *bh; + struct nilfs_cpfile_header *header; + struct nilfs_checkpoint *cp; + __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[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, + struct nilfs_cpinfo *ci, size_t nci) +{ + switch (mode) { + case NILFS_CHECKPOINT: + return nilfs_cpfile_do_get_cpinfo(cpfile, cnop, ci, nci); + case NILFS_SNAPSHOT: + return nilfs_cpfile_do_get_ssinfo(cpfile, cnop, ci, 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; + int ret; + + nci = nilfs_cpfile_do_get_cpinfo(cpfile, &tcno, &ci, 1); + if (nci < 0) + return nci; + else if (nci == 0 || ci.ci_cno != cno) + return -ENOENT; + + /* cannot delete the latest checkpoint nor snapshots */ + ret = nilfs_cpinfo_snapshot(&ci); + if (ret < 0) + return ret; + else if (ret > 0 || cno == nilfs_mdt_cno(cpfile) - 1) + return -EPERM; + + 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; + + if (cno == 0) + return -ENOENT; /* checkpoint number 0 is invalid */ + 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); + 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: + * bd_mount_sem 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. + */ + down(&nilfs->ns_bdev->bd_mount_sem); + 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); + up(&nilfs->ns_bdev->bd_mount_sem); + 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; +} |