nilfs2: issue discard request after cleaning segments

This adds a function to send discard requests for given array of
segment numbers, and calls the function when garbage collection
succeeded.

Signed-off-by: Jiro SEKIBA <jir@unicus.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

1 files changed, 38 insertions, 0 deletions

diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c
index 6241e1722efc..92733d5651d2 100644
--- a/fs/nilfs2/the_nilfs.c
+++ b/fs/nilfs2/the_nilfs.c
@@ -646,6 +646,44 @@ int init_nilfs(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi, char *data)
         goto out;
 }
 
+int nilfs_discard_segments(struct the_nilfs *nilfs, __u64 *segnump,
+                            size_t nsegs)
+{
+        sector_t seg_start, seg_end;
+        sector_t start = 0, nblocks = 0;
+        unsigned int sects_per_block;
+        __u64 *sn;
+        int ret = 0;
+
+        sects_per_block = (1 << nilfs->ns_blocksize_bits) /
+                bdev_logical_block_size(nilfs->ns_bdev);
+        for (sn = segnump; sn < segnump + nsegs; sn++) {
+                nilfs_get_segment_range(nilfs, *sn, &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,
+                                                   DISCARD_FL_BARRIER);
+                        if (ret < 0)
+                                return ret;
+                        nblocks = 0;
+                }
+        }
+        if (nblocks)
+                ret = blkdev_issue_discard(nilfs->ns_bdev,
+                                           start * sects_per_block,
+                                           nblocks * sects_per_block,
+                                           GFP_NOFS, DISCARD_FL_BARRIER);
+        return ret;
+}
+
 int nilfs_count_free_blocks(struct the_nilfs *nilfs, sector_t *nblocks)
 {
         struct inode *dat = nilfs_dat_inode(nilfs);