This patch adds the nilfs_sufile_trim_fs function, which takes a
fstrim_range structure and calls blkdev_issue_discard for every
clean segment in the specified range. The range is truncated to sector
boundaries.
Signed-off-by: Andreas Rohner <andreas.rohner@xxxxxxx>
---
fs/nilfs2/sufile.c | 144 +++++++++++++++++++++++++++++++++++++++++++++++++++++
fs/nilfs2/sufile.h | 1 +
2 files changed, 145 insertions(+)
diff --git a/fs/nilfs2/sufile.c b/fs/nilfs2/sufile.c
index 3127e9f..3605cc9 100644
--- a/fs/nilfs2/sufile.c
+++ b/fs/nilfs2/sufile.c
@@ -870,6 +870,150 @@ ssize_t nilfs_sufile_get_suinfo(struct inode *sufile, __u64 segnum, void *buf,
}
/**
+ * 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 sector boundary
+ * and start+len is rounded down. For each clean segment blkdev_issue_discard
+ * function is invoked to trim it.
+ *
+ * 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, real_start, real_end,
+ start = 0, nblocks = 0;
+ u64 segnum, end, minlen, trimmed = 0;
+ int ret = 0;
+ unsigned int sect_size, sects_per_block;
+
+ sect_size = bdev_logical_block_size(nilfs->ns_bdev);
+ sects_per_block = (1 << nilfs->ns_blocksize_bits) / sect_size;
+ real_start = (range->start + sect_size - 1) / sect_size;
+ real_end = (range->start + range->len) / sect_size;
+ segnum = nilfs_get_segnum_of_block(nilfs, real_start / sects_per_block);
+ end = nilfs_get_segnum_of_block(nilfs, ((real_end + sects_per_block - 1)
+ / sects_per_block) + nilfs->ns_blocks_per_segment - 1);
+ minlen = range->minlen / sect_size;
+
+
+ if (end > nilfs->ns_nsegments)
+ end = nilfs->ns_nsegments;
+ if (segnum >= nilfs->ns_nsegments || end <= segnum)
+ goto out;
+
+ down_read(&NILFS_MDT(sufile)->mi_sem);
+
+ while (segnum < end) {
+ n = nilfs_sufile_segment_usages_in_block(sufile, segnum,
+ end - 1);
+
+ 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);
+ 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 */
+ start *= sects_per_block;
+ nblocks *= sects_per_block;
+ if (start < real_start) {
+ nblocks -= real_start - start;
+ start = real_start;
+ }
+ if (start + nblocks > real_end)
+ nblocks = real_end - start;
+
+ if (nblocks >= minlen) {
+ kunmap_atomic(kaddr);
+
+ ret = blkdev_issue_discard(nilfs->ns_bdev,
+ start, nblocks, GFP_NOFS, 0);
+ if (ret < 0) {
+ put_bh(su_bh);
+ goto out_sem;
+ }
+
+ trimmed += nblocks;
+ kaddr = kmap_atomic(su_bh->b_page);
+ 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);
+ put_bh(su_bh);
+ }
+
+
+ if (nblocks) {
+ /* discard last extent */
+ start *= sects_per_block;
+ nblocks *= sects_per_block;
+ if (start < real_start) {
+ nblocks -= real_start - start;
+ start = real_start;
+ }
+ if (start + nblocks > real_end)
+ nblocks = real_end - start;
+
+ if (nblocks >= minlen) {
+ ret = blkdev_issue_discard(nilfs->ns_bdev, start,
+ nblocks, GFP_NOFS, 0);
+ if (!ret)
+ trimmed += nblocks;
+ }
+ }
+
+out_sem:
+ up_read(&NILFS_MDT(sufile)->mi_sem);
+out:
+ range->len = trimmed * sect_size;
+ return ret;
+}
+
+/**
* nilfs_sufile_read - read or get sufile inode
* @sb: super block instance
* @susize: size of a segment usage entry
diff --git a/fs/nilfs2/sufile.h b/fs/nilfs2/sufile.h
index e84bc5b..2434abd 100644
--- a/fs/nilfs2/sufile.h
+++ b/fs/nilfs2/sufile.h
@@ -65,6 +65,7 @@ void nilfs_sufile_do_set_error(struct inode *, __u64, struct buffer_head *,
int nilfs_sufile_resize(struct inode *sufile, __u64 newnsegs);
int nilfs_sufile_read(struct super_block *sb, size_t susize,
struct nilfs_inode *raw_inode, struct inode **inodep);
+int nilfs_sufile_trim_fs(struct inode *sufile, struct fstrim_range *range);
/**
* nilfs_sufile_scrap - make a segment garbage
--
1.9.0
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