cpfile.rar_CPFile-v1.1_checkpoint_cpfile

/* * cpfile.c - NILFS checkpoint file. * * * * 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); 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); 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)\