Hi Sekiba-san,
On Sat, 30 Jan 2010 13:28:52 +0900, Jiro SEKIBA <jir@xxxxxxxxx> wrote:
> Hi,
>
> This is the revised patch. The original patch is found in
> nilfs/experimental tree. I add mount option to enable the feature
> and modify block devcie layer for recent block device layer.
>
>
> 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: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxxxxxx>
> Signed-off-by: Jiro SEKIBA <jir@xxxxxxxxx>
Thank you for sending this revised patch.
I'll inline an additional comment.
> ---
> Documentation/filesystems/nilfs2.txt | 3 ++
> fs/nilfs2/segment.c | 3 ++
> fs/nilfs2/super.c | 8 +++++-
> fs/nilfs2/the_nilfs.c | 45 ++++++++++++++++++++++++++++++++++
> fs/nilfs2/the_nilfs.h | 1 +
> include/linux/nilfs2_fs.h | 1 +
> 6 files changed, 60 insertions(+), 1 deletions(-)
>
> 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 @@ norecovery Disable recovery of the filesystem on mount.
> 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 17584c5..db6869f 100644
> --- a/fs/nilfs2/segment.c
> +++ b/fs/nilfs2/segment.c
> @@ -2560,6 +2560,9 @@ int nilfs_clean_segments(struct super_block *sb, struct nilfs_argv *argv,
> set_current_state(TASK_INTERRUPTIBLE);
> schedule_timeout(sci->sc_interval);
> }
> + if (nilfs_test_opt(sbi, DISCARD))
> + nilfs_discard_segments(nilfs, sci->sc_freesegs,
> + sci->sc_nfreesegs);
>
> 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 @@ static int nilfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
> 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 @@ static const struct export_operations nilfs_export_ops = {
> 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 @@ static match_table_t tokens = {
> {Opt_snapshot, "cp=%u"},
> {Opt_order, "order=%s"},
> {Opt_norecovery, "norecovery"},
> + {Opt_discard, "discard"},
> {Opt_err, NULL}
> };
>
> @@ -614,6 +617,9 @@ static int parse_options(char *options, struct super_block *sb)
> 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..9ad5b83 100644
> --- a/fs/nilfs2/the_nilfs.c
> +++ b/fs/nilfs2/the_nilfs.c
> @@ -646,6 +646,51 @@ int init_nilfs(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi, char *data)
> goto out;
> }
>
> +void 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)
> + goto failed;
> + nblocks = 0;
> + }
> + }
> + if (nblocks) {
> + ret = blkdev_issue_discard(nilfs->ns_bdev,
> + start * sects_per_block,
> + nblocks * sects_per_block,
> + GFP_NOFS, DISCARD_FL_BARRIER);
> + if (ret < 0)
> + goto failed;
> + }
> + return;
> + failed:
> + printk(KERN_WARNING "NILFS warning: error %d on discard request, "
> + "turning discards off for the device\n", ret);
> + nilfs_clear_opt(nilfs->ns_current, DISCARD);
I prefer to move these error handling code to the caller to remove the
nilfs->ns_current reference.
You can change nilfs_discard_segments to make it return error codes,
and then the above printk and nilfs_clear_opt() can be moved to the
caller which has a valid sbi reference.
> +}
> +
> 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..8e3de6e 100644
> --- a/fs/nilfs2/the_nilfs.h
> +++ b/fs/nilfs2/the_nilfs.h
> @@ -221,6 +221,7 @@ struct the_nilfs *find_or_create_nilfs(struct block_device *);
> 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 *);
> +void 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 @@ struct nilfs_super_root {
> semantics also for data */
> #define NILFS_MOUNT_NORECOVERY 0x4000 /* Disable write access during
> mount-time recovery */
> +#define NILFS_MOUNT_DISCARD 0x8000 /* Issue DISCARD requests */
>
>
> /**
> --
> 1.5.6.5
>
> --
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Regards,
Ryusuke Konishi
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