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.

Signed-off-by: Andreas Rohner <[email protected]>
---
 fs/nilfs2/sufile.c | 114 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 fs/nilfs2/sufile.h |   1 +
 2 files changed, 115 insertions(+)

diff --git a/fs/nilfs2/sufile.c b/fs/nilfs2/sufile.c
index 3127e9f..022b17f 100644
--- a/fs/nilfs2/sufile.c
+++ b/fs/nilfs2/sufile.c
@@ -870,6 +870,120 @@ 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. 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 susz = NILFS_MDT(sufile)->mi_entry_size;
+       ssize_t n;
+       sector_t seg_start, seg_end, start = 0, nblocks = 0;
+       u64 segnum, end, minlen, trimmed = 0;
+       int i, ret = 0;
+       unsigned long segusages_per_block;
+       unsigned int sects_per_block;
+
+       segusages_per_block = nilfs_sufile_segment_usages_per_block(sufile);
+       sects_per_block = (1 << nilfs->ns_blocksize_bits) /
+               bdev_logical_block_size(nilfs->ns_bdev);
+       segnum = nilfs_get_segnum_of_block(nilfs, range->start >>
+                       nilfs->ns_blocksize_bits);
+       end = nilfs_get_segnum_of_block(nilfs, (range->start + range->len)
+                       >> nilfs->ns_blocksize_bits);
+       minlen = range->minlen >> nilfs->ns_blocksize_bits;
+
+       if (minlen > nilfs->ns_blocks_per_segment ||
+           segnum >= nilfs->ns_nsegments ||
+           range->len < nilfs->ns_blocksize)
+               return -EINVAL;
+       if (end > nilfs->ns_nsegments)
+               end = nilfs->ns_nsegments;
+       if (end == segnum)
+               goto out;
+
+       down_read(&NILFS_MDT(sufile)->mi_sem);
+
+       while (segnum < end) {
+               n = min_t(unsigned long,
+                         segusages_per_block -
+                                 nilfs_sufile_get_offset(sufile, segnum),
+                         end - segnum);
+               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(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 = seg_start;
+                               nblocks = seg_end - seg_start + 1;
+                       } else if (start + nblocks == seg_start) {
+                               nblocks += seg_end - seg_start + 1;
+                       } else {
+                               ret = blkdev_issue_discard(nilfs->ns_bdev,
+                                               start * sects_per_block,
+                                               nblocks * sects_per_block,
+                                               GFP_NOFS, 0);
+                               if (ret < 0) {
+                                       kunmap(kaddr);
+                                       put_bh(su_bh);
+                                       goto out_sem;
+                               }
+
+                               trimmed += nblocks;
+                               nblocks = 0;
+                       }
+               }
+               kunmap(kaddr);
+               put_bh(su_bh);
+       }
+
+       if (nblocks) {
+               ret = blkdev_issue_discard(nilfs->ns_bdev,
+                                          start * sects_per_block,
+                                          nblocks * sects_per_block,
+                                          GFP_NOFS, 0);
+               if (!ret)
+                       trimmed += nblocks;
+       }
+
+out_sem:
+       up_read(&NILFS_MDT(sufile)->mi_sem);
+out:
+       range->len = trimmed << nilfs->ns_blocksize_bits;
+       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
-- 
1.8.5.4

--
To unsubscribe from this list: send the line "unsubscribe linux-nilfs" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Reply via email to