nilfs2: add ioctl which limits range of segment to be allocated
This adds a new ioctl command which limits range of segment to be allocated. This is intended to gather data whithin a range of the partition before shrinking the filesystem, or to control new log location for some purpose. If a range is specified by the ioctl, segment allocator of nilfs tries to allocate new segments from the range unless no free segments are available there. Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
This commit is contained in:
Ryusuke Konishi
parent
56eb553885
commit
619205da5b
4 changed files with 100 additions and 10 deletions
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@ -698,6 +698,38 @@ static int nilfs_ioctl_sync(struct inode *inode, struct file *filp,
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return 0;
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}
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static int nilfs_ioctl_set_alloc_range(struct inode *inode, void __user *argp)
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{
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struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
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__u64 range[2];
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__u64 minseg, maxseg;
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unsigned long segbytes;
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int ret = -EPERM;
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if (!capable(CAP_SYS_ADMIN))
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goto out;
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ret = -EFAULT;
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if (copy_from_user(range, argp, sizeof(__u64[2])))
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goto out;
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ret = -ERANGE;
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if (range[1] > i_size_read(inode->i_sb->s_bdev->bd_inode))
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goto out;
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segbytes = nilfs->ns_blocks_per_segment * nilfs->ns_blocksize;
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minseg = range[0] + segbytes - 1;
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do_div(minseg, segbytes);
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maxseg = NILFS_SB2_OFFSET_BYTES(range[1]);
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do_div(maxseg, segbytes);
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maxseg--;
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ret = nilfs_sufile_set_alloc_range(nilfs->ns_sufile, minseg, maxseg);
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out:
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return ret;
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}
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static int nilfs_ioctl_get_info(struct inode *inode, struct file *filp,
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unsigned int cmd, void __user *argp,
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size_t membsz,
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@ -763,6 +795,8 @@ long nilfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
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return nilfs_ioctl_clean_segments(inode, filp, cmd, argp);
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case NILFS_IOCTL_SYNC:
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return nilfs_ioctl_sync(inode, filp, cmd, argp);
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case NILFS_IOCTL_SET_ALLOC_RANGE:
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return nilfs_ioctl_set_alloc_range(inode, argp);
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default:
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return -ENOTTY;
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}
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@ -33,7 +33,9 @@
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struct nilfs_sufile_info {
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struct nilfs_mdt_info mi;
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unsigned long ncleansegs;
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unsigned long ncleansegs;/* number of clean segments */
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__u64 allocmin; /* lower limit of allocatable segment range */
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__u64 allocmax; /* upper limit of allocatable segment range */
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};
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static inline struct nilfs_sufile_info *NILFS_SUI(struct inode *sufile)
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@ -247,6 +249,35 @@ int nilfs_sufile_update(struct inode *sufile, __u64 segnum, int create,
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return ret;
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}
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/**
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* nilfs_sufile_set_alloc_range - limit range of segment to be allocated
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* @sufile: inode of segment usage file
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* @start: minimum segment number of allocatable region (inclusive)
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* @end: maximum segment number of allocatable region (inclusive)
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*
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* Return Value: On success, 0 is returned. On error, one of the
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* following negative error codes is returned.
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*
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* %-ERANGE - invalid segment region
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*/
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int nilfs_sufile_set_alloc_range(struct inode *sufile, __u64 start, __u64 end)
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{
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struct nilfs_sufile_info *sui = NILFS_SUI(sufile);
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__u64 nsegs;
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int ret = -ERANGE;
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down_write(&NILFS_MDT(sufile)->mi_sem);
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nsegs = nilfs_sufile_get_nsegments(sufile);
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if (start <= end && end < nsegs) {
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sui->allocmin = start;
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sui->allocmax = end;
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ret = 0;
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}
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up_write(&NILFS_MDT(sufile)->mi_sem);
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return ret;
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}
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/**
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* nilfs_sufile_alloc - allocate a segment
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* @sufile: inode of segment usage file
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@ -269,11 +300,12 @@ int nilfs_sufile_alloc(struct inode *sufile, __u64 *segnump)
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struct buffer_head *header_bh, *su_bh;
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struct nilfs_sufile_header *header;
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struct nilfs_segment_usage *su;
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struct nilfs_sufile_info *sui = NILFS_SUI(sufile);
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size_t susz = NILFS_MDT(sufile)->mi_entry_size;
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__u64 segnum, maxsegnum, last_alloc;
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void *kaddr;
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unsigned long nsegments, ncleansegs, nsus;
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int ret, i, j;
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unsigned long nsegments, ncleansegs, nsus, cnt;
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int ret, j;
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down_write(&NILFS_MDT(sufile)->mi_sem);
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@ -287,13 +319,31 @@ int nilfs_sufile_alloc(struct inode *sufile, __u64 *segnump)
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kunmap_atomic(kaddr, KM_USER0);
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nsegments = nilfs_sufile_get_nsegments(sufile);
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maxsegnum = sui->allocmax;
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segnum = last_alloc + 1;
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maxsegnum = nsegments - 1;
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for (i = 0; i < nsegments; i += nsus) {
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if (segnum >= nsegments) {
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/* wrap around */
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segnum = 0;
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if (segnum < sui->allocmin || segnum > sui->allocmax)
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segnum = sui->allocmin;
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for (cnt = 0; cnt < nsegments; cnt += nsus) {
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if (segnum > maxsegnum) {
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if (cnt < sui->allocmax - sui->allocmin + 1) {
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/*
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* wrap around in the limited region.
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* if allocation started from
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* sui->allocmin, this never happens.
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*/
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segnum = sui->allocmin;
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maxsegnum = last_alloc;
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} else if (segnum > sui->allocmin &&
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sui->allocmax + 1 < nsegments) {
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segnum = sui->allocmax + 1;
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maxsegnum = nsegments - 1;
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} else if (sui->allocmin > 0) {
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segnum = 0;
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maxsegnum = sui->allocmin - 1;
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} else {
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break; /* never happens */
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}
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}
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ret = nilfs_sufile_get_segment_usage_block(sufile, segnum, 1,
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&su_bh);
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@ -319,7 +369,7 @@ int nilfs_sufile_alloc(struct inode *sufile, __u64 *segnump)
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header->sh_last_alloc = cpu_to_le64(segnum);
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kunmap_atomic(kaddr, KM_USER0);
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NILFS_SUI(sufile)->ncleansegs--;
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sui->ncleansegs--;
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nilfs_mdt_mark_buffer_dirty(header_bh);
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nilfs_mdt_mark_buffer_dirty(su_bh);
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nilfs_mdt_mark_dirty(sufile);
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@ -679,6 +729,9 @@ int nilfs_sufile_read(struct super_block *sb, size_t susize,
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kunmap_atomic(kaddr, KM_USER0);
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brelse(header_bh);
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sui->allocmax = nilfs_sufile_get_nsegments(sufile) - 1;
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sui->allocmin = 0;
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unlock_new_inode(sufile);
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out:
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*inodep = sufile;
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@ -36,6 +36,7 @@ static inline unsigned long nilfs_sufile_get_nsegments(struct inode *sufile)
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unsigned long nilfs_sufile_get_ncleansegs(struct inode *sufile);
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int nilfs_sufile_set_alloc_range(struct inode *sufile, __u64 start, __u64 end);
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int nilfs_sufile_alloc(struct inode *, __u64 *);
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int nilfs_sufile_mark_dirty(struct inode *sufile, __u64 segnum);
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int nilfs_sufile_set_segment_usage(struct inode *sufile, __u64 segnum,
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@ -845,5 +845,7 @@ struct nilfs_bdesc {
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_IOR(NILFS_IOCTL_IDENT, 0x8A, __u64)
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#define NILFS_IOCTL_RESIZE \
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_IOW(NILFS_IOCTL_IDENT, 0x8B, __u64)
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#define NILFS_IOCTL_SET_ALLOC_RANGE \
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_IOW(NILFS_IOCTL_IDENT, 0x8C, __u64[2])
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#endif /* _LINUX_NILFS_FS_H */
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