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>
diff --git a/Documentation/filesystems/nilfs2.txt b/Documentation/filesystems/nilfs2.txt
index 839efd8..cf6d0d8 100644
--- a/Documentation/filesystems/nilfs2.txt
+++ b/Documentation/filesystems/nilfs2.txt
@@ -74,6 +74,9 @@
This disables every write access on the device for
read-only mounts or snapshots. This option will fail
for r/w mounts on an unclean volume.
+discard Issue discard/TRIM commands to the underlying block
+ device when blocks are freed. This is useful for SSD
+ devices and sparse/thinly-provisioned LUNs.
NILFS2 usage
============
diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c
index 105b508..9280b0f 100644
--- a/fs/nilfs2/segment.c
+++ b/fs/nilfs2/segment.c
@@ -2560,6 +2560,16 @@
set_current_state(TASK_INTERRUPTIBLE);
schedule_timeout(sci->sc_interval);
}
+ if (nilfs_test_opt(sbi, DISCARD)) {
+ int ret = nilfs_discard_segments(nilfs, sci->sc_freesegs,
+ sci->sc_nfreesegs);
+ if (ret) {
+ printk(KERN_WARNING
+ "NILFS warning: error %d on discard request, "
+ "turning discards off for the device\n", ret);
+ nilfs_clear_opt(sbi, DISCARD);
+ }
+ }
out_unlock:
sci->sc_freesegs = NULL;
diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c
index 8173fae..3f88401 100644
--- a/fs/nilfs2/super.c
+++ b/fs/nilfs2/super.c
@@ -481,6 +481,8 @@
seq_printf(seq, ",order=strict");
if (nilfs_test_opt(sbi, NORECOVERY))
seq_printf(seq, ",norecovery");
+ if (nilfs_test_opt(sbi, DISCARD))
+ seq_printf(seq, ",discard");
return 0;
}
@@ -550,7 +552,7 @@
enum {
Opt_err_cont, Opt_err_panic, Opt_err_ro,
Opt_nobarrier, Opt_snapshot, Opt_order, Opt_norecovery,
- Opt_err,
+ Opt_discard, Opt_err,
};
static match_table_t tokens = {
@@ -561,6 +563,7 @@
{Opt_snapshot, "cp=%u"},
{Opt_order, "order=%s"},
{Opt_norecovery, "norecovery"},
+ {Opt_discard, "discard"},
{Opt_err, NULL}
};
@@ -614,6 +617,9 @@
case Opt_norecovery:
nilfs_set_opt(sbi, NORECOVERY);
break;
+ case Opt_discard:
+ nilfs_set_opt(sbi, DISCARD);
+ break;
default:
printk(KERN_ERR
"NILFS: Unrecognized mount option \"%s\"\n", p);
diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c
index 6241e17..92733d5 100644
--- a/fs/nilfs2/the_nilfs.c
+++ b/fs/nilfs2/the_nilfs.c
@@ -646,6 +646,44 @@
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);
diff --git a/fs/nilfs2/the_nilfs.h b/fs/nilfs2/the_nilfs.h
index 589786e..fd057f8 100644
--- a/fs/nilfs2/the_nilfs.h
+++ b/fs/nilfs2/the_nilfs.h
@@ -221,6 +221,7 @@
void put_nilfs(struct the_nilfs *);
int init_nilfs(struct the_nilfs *, struct nilfs_sb_info *, char *);
int load_nilfs(struct the_nilfs *, struct nilfs_sb_info *);
+int nilfs_discard_segments(struct the_nilfs *, __u64 *, size_t);
int nilfs_count_free_blocks(struct the_nilfs *, sector_t *);
struct nilfs_sb_info *nilfs_find_sbinfo(struct the_nilfs *, int, __u64);
int nilfs_checkpoint_is_mounted(struct the_nilfs *, __u64, int);
diff --git a/include/linux/nilfs2_fs.h b/include/linux/nilfs2_fs.h
index 3fe02cf..640702e 100644
--- a/include/linux/nilfs2_fs.h
+++ b/include/linux/nilfs2_fs.h
@@ -153,6 +153,7 @@
semantics also for data */
#define NILFS_MOUNT_NORECOVERY 0x4000 /* Disable write access during
mount-time recovery */
+#define NILFS_MOUNT_DISCARD 0x8000 /* Issue DISCARD requests */
/**