/**
* nilfs_sufile_trim_fs() - trim ioctl handle function
* @sufile: inode of segment usage file
* @range: fstrim_range structure
*
* start: First Byte to trim
* len: number of Bytes to trim from start
* minlen: minimum extent length in Bytes
*
* Decription: nilfs_sufile_trim_fs goes through all segments containing bytes
* from start to start+len. start is rounded up to the next block boundary
* and start+len is rounded down. For each clean segment blkdev_issue_discard
* function is invoked.
*
* Return Value: On success, 0 is returned or negative error code, otherwise.
*/
int nilfs_sufile_trim_fs(struct inode *sufile, struct fstrim_range *range)
{
struct the_nilfs *nilfs = sufile->i_sb->s_fs_info;
struct buffer_head *su_bh;
struct nilfs_segment_usage *su;
void *kaddr;
size_t n, i, susz = NILFS_MDT(sufile)->mi_entry_size;
sector_t seg_start, seg_end, start_block, end_block;
sector_t start = 0, nblocks = 0;
u64 segnum, segnum_end, minlen, len, max_blocks, ndiscarded = 0;
int ret = 0;
unsigned int sects_per_block;
sects_per_block = (1 << nilfs->ns_blocksize_bits) /
bdev_logical_block_size(nilfs->ns_bdev);
len = range->len >> nilfs->ns_blocksize_bits;
minlen = range->minlen >> nilfs->ns_blocksize_bits;
max_blocks = ((u64)nilfs->ns_nsegments * nilfs->ns_blocks_per_segment);
if (!len || range->start >= max_blocks << nilfs->ns_blocksize_bits)
return -EINVAL;
start_block = (range->start + nilfs->ns_blocksize - 1) >>
nilfs->ns_blocksize_bits;
/*
* range->len can be very large (actually, it is set to
* ULLONG_MAX by default) - truncate upper end of the range
* carefully so as not to overflow.
*/
if (max_blocks - start_block < len)
end_block = max_blocks - 1;
else
end_block = start_block + len - 1;
segnum = nilfs_get_segnum_of_block(nilfs, start_block);
segnum_end = nilfs_get_segnum_of_block(nilfs, end_block);
down_read(&NILFS_MDT(sufile)->mi_sem);
while (segnum <= segnum_end) {
n = nilfs_sufile_segment_usages_in_block(sufile, segnum,
segnum_end);
ret = nilfs_sufile_get_segment_usage_block(sufile, segnum, 0,
&su_bh);
if (ret < 0) {
if (ret != -ENOENT)
goto out_sem;
/* hole */
segnum += n;
continue;
}
kaddr = kmap_atomic(su_bh->b_page, KM_USER0);
su = nilfs_sufile_block_get_segment_usage(sufile, segnum,
su_bh, kaddr);
for (i = 0; i < n; ++i, ++segnum, su = (void *)su + susz) {
if (!nilfs_segment_usage_clean(su))
continue;
nilfs_get_segment_range(nilfs, segnum, &seg_start,
&seg_end);
if (!nblocks) {
/* start new extent */
start = seg_start;
nblocks = seg_end - seg_start + 1;
continue;
}
if (start + nblocks == seg_start) {
/* add to previous extent */
nblocks += seg_end - seg_start + 1;
continue;
}
/* discard previous extent */
if (start < start_block) {
nblocks -= start_block - start;
start = start_block;
}
if (nblocks >= minlen) {
kunmap_atomic(kaddr, KM_USER0);
ret = compat_blkdev_issue_discard(
nilfs->ns_bdev, start * sects_per_block,
nblocks * sects_per_block, GFP_NOFS, 0);
if (ret < 0) {
put_bh(su_bh);
goto out_sem;
}
ndiscarded += nblocks;
kaddr = kmap_atomic(su_bh->b_page, KM_USER0);
su = nilfs_sufile_block_get_segment_usage(
sufile, segnum, su_bh, kaddr);
}
/* start new extent */
start = seg_start;
nblocks = seg_end - seg_start + 1;
}
kunmap_atomic(kaddr, KM_USER0);
put_bh(su_bh);
}
if (nblocks) {
/* discard last extent */
if (start < start_block) {
nblocks -= start_block - start;
start = start_block;
}
if (start + nblocks > end_block + 1)
nblocks = end_block - start + 1;
if (nblocks >= minlen) {
ret = compat_blkdev_issue_discard(
nilfs->ns_bdev, start * sects_per_block,
nblocks * sects_per_block, GFP_NOFS, 0);
if (!ret)
ndiscarded += nblocks;
}
}
out_sem:
up_read(&NILFS_MDT(sufile)->mi_sem);
range->len = ndiscarded << nilfs->ns_blocksize_bits;
return ret;
}
int nilfs_sufile_alloc(struct inode *sufile, __u64 *segnump)
{
struct buffer_head *header_bh, *su_bh;
struct nilfs_sufile_header *header;
struct nilfs_segment_usage *su;
struct nilfs_sufile_info *sui = NILFS_SUI(sufile);
size_t susz = NILFS_MDT(sufile)->mi_entry_size;
__u64 segnum, maxsegnum, last_alloc;
void *kaddr;
unsigned long nsegments, ncleansegs, nsus, cnt;
int ret, j;
down_write(&NILFS_MDT(sufile)->mi_sem);
ret = nilfs_sufile_get_header_block(sufile, &header_bh);
if (ret < 0)
goto out_sem;
kaddr = kmap_atomic(header_bh->b_page);
header = kaddr + bh_offset(header_bh);
ncleansegs = le64_to_cpu(header->sh_ncleansegs);
last_alloc = le64_to_cpu(header->sh_last_alloc);
kunmap_atomic(kaddr);
nsegments = nilfs_sufile_get_nsegments(sufile);
maxsegnum = sui->allocmax;
segnum = last_alloc + 1;
if (segnum < sui->allocmin || segnum > sui->allocmax)
segnum = sui->allocmin;
for (cnt = 0; cnt < nsegments; cnt += nsus) {
if (segnum > maxsegnum) {
if (cnt < sui->allocmax - sui->allocmin + 1) {
segnum = sui->allocmin;
maxsegnum = last_alloc;
} else if (segnum > sui->allocmin &&
sui->allocmax + 1 < nsegments) {
segnum = sui->allocmax + 1;
maxsegnum = nsegments - 1;
} else if (sui->allocmin > 0) {
segnum = 0;
maxsegnum = sui->allocmin - 1;
} else {
break;
}
}
ret = nilfs_sufile_get_segment_usage_block(sufile, segnum, 1,
&su_bh);
if (ret < 0)
goto out_header;
kaddr = kmap_atomic(su_bh->b_page);
su = nilfs_sufile_block_get_segment_usage(
sufile, segnum, su_bh, kaddr);
nsus = nilfs_sufile_segment_usages_in_block(
sufile, segnum, maxsegnum);
for (j = 0; j < nsus; j++, su = (void *)su + susz, segnum++) {
if (!nilfs_segment_usage_clean(su))
continue;
nilfs_segment_usage_set_dirty(su);
kunmap_atomic(kaddr);
kaddr = kmap_atomic(header_bh->b_page);
header = kaddr + bh_offset(header_bh);
le64_add_cpu(&header->sh_ncleansegs, -1);
le64_add_cpu(&header->sh_ndirtysegs, 1);
header->sh_last_alloc = cpu_to_le64(segnum);
kunmap_atomic(kaddr);
sui->ncleansegs--;
mark_buffer_dirty(header_bh);
mark_buffer_dirty(su_bh);
nilfs_mdt_mark_dirty(sufile);
brelse(su_bh);
*segnump = segnum;
goto out_header;
}
kunmap_atomic(kaddr);
brelse(su_bh);
}
ret = -ENOSPC;
out_header:
brelse(header_bh);
out_sem:
up_write(&NILFS_MDT(sufile)->mi_sem);
return ret;
}
/**
* nilfs_sufile_alloc - allocate a segment
* @sufile: inode of segment usage file
* @segnump: pointer to segment number
*
* Description: nilfs_sufile_alloc() allocates a clean segment.
*
* Return Value: On success, 0 is returned and the segment number of the
* allocated segment is stored in the place pointed by @segnump. On error, one
* of the following negative error codes is returned.
*
* %-EIO - I/O error.
*
* %-ENOMEM - Insufficient amount of memory available.
*
* %-ENOSPC - No clean segment left.
*/
int nilfs_sufile_alloc(struct inode *sufile, __u64 *segnump)
{
struct buffer_head *header_bh, *su_bh;
struct nilfs_sufile_header *header;
struct nilfs_segment_usage *su;
size_t susz = NILFS_MDT(sufile)->mi_entry_size;
__u64 segnum, maxsegnum, last_alloc;
void *kaddr;
unsigned long nsegments, ncleansegs, nsus;
int ret, i, j;
down_write(&NILFS_MDT(sufile)->mi_sem);
ret = nilfs_sufile_get_header_block(sufile, &header_bh);
if (ret < 0)
goto out_sem;
kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
header = nilfs_sufile_block_get_header(sufile, header_bh, kaddr);
ncleansegs = le64_to_cpu(header->sh_ncleansegs);
last_alloc = le64_to_cpu(header->sh_last_alloc);
kunmap_atomic(kaddr, KM_USER0);
nsegments = nilfs_sufile_get_nsegments(sufile);
segnum = last_alloc + 1;
maxsegnum = nsegments - 1;
for (i = 0; i < nsegments; i += nsus) {
if (segnum >= nsegments) {
/* wrap around */
segnum = 0;
maxsegnum = last_alloc;
}
ret = nilfs_sufile_get_segment_usage_block(sufile, segnum, 1,
&su_bh);
if (ret < 0)
goto out_header;
kaddr = kmap_atomic(su_bh->b_page, KM_USER0);
su = nilfs_sufile_block_get_segment_usage(
sufile, segnum, su_bh, kaddr);
nsus = nilfs_sufile_segment_usages_in_block(
sufile, segnum, maxsegnum);
for (j = 0; j < nsus; j++, su = (void *)su + susz, segnum++) {
if (!nilfs_segment_usage_clean(su))
continue;
/* found a clean segment */
nilfs_segment_usage_set_dirty(su);
kunmap_atomic(kaddr, KM_USER0);
kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
header = nilfs_sufile_block_get_header(
sufile, header_bh, kaddr);
le64_add_cpu(&header->sh_ncleansegs, -1);
le64_add_cpu(&header->sh_ndirtysegs, 1);
header->sh_last_alloc = cpu_to_le64(segnum);
kunmap_atomic(kaddr, KM_USER0);
nilfs_mdt_mark_buffer_dirty(header_bh);
nilfs_mdt_mark_buffer_dirty(su_bh);
nilfs_mdt_mark_dirty(sufile);
brelse(su_bh);
*segnump = segnum;
goto out_header;
}
kunmap_atomic(kaddr, KM_USER0);
brelse(su_bh);
}
/* no segments left */
ret = -ENOSPC;
out_header:
brelse(header_bh);
out_sem:
up_write(&NILFS_MDT(sufile)->mi_sem);
return ret;
}
