Re: [PATCH v4] f2fs: support soft block reservation
From: Chao Yu
Date: Thu Oct 26 2017 - 23:28:34 EST
On 2017/10/27 11:11, Yunlong Song wrote:
> It renames reserved_blocks sysfs interface to target_reserved_blocks,
> and supports to extend it to be soft threshold, which allows user
> configure it exceeding current available user space. So this patch
> also introduces a new sysfs interface called current_reserved_blocks to
> show the current blocks which have already been reserved.
>
> Signed-off-by: Yunlong Song <yunlong.song@xxxxxxxxxx>
> Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx>
> ---
> Documentation/ABI/testing/sysfs-fs-f2fs | 15 +++++++++++++--
> fs/f2fs/f2fs.h | 15 ++++++++++++---
> fs/f2fs/super.c | 5 +++--
> fs/f2fs/sysfs.c | 20 +++++++++++++++-----
> 4 files changed, 43 insertions(+), 12 deletions(-)
>
> diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs
> index 11b7f4e..482d78b 100644
> --- a/Documentation/ABI/testing/sysfs-fs-f2fs
> +++ b/Documentation/ABI/testing/sysfs-fs-f2fs
> @@ -134,11 +134,22 @@ Contact: "Sheng Yong" <shengyong1@xxxxxxxxxx>
> Description:
> Controls the injection type.
>
> -What: /sys/fs/f2fs/<disk>/reserved_blocks
> +What: /sys/fs/f2fs/<disk>/target_reserved_blocks
For backward compatibility, how about keep this interface name, instead
just update its description?
Thanks,
> Date: June 2017
> Contact: "Chao Yu" <yuchao0@xxxxxxxxxx>
> Description:
> - Controls current reserved blocks in system.
> + Controls target reserved blocks in system, the threshold
> + is soft, it could exceed current available user space.
> +
> +What: /sys/fs/f2fs/<disk>/current_reserved_blocks
> +Date: October 2017
> +Contact: "Yunlong Song" <yunlong.song@xxxxxxxxxx>
> +Contact: "Chao Yu" <yuchao0@xxxxxxxxxx>
> +Description:
> + Shows current reserved blocks in system, it may be temporarily
> + smaller than target_reserved_blocks, but will gradually
> + increase to target_reserved_blocks when more free blocks are
> + freed by user later.
>
> What: /sys/fs/f2fs/<disk>/gc_urgent
> Date: August 2017
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index 13a96b8..c26fccb 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -1081,7 +1081,8 @@ struct f2fs_sb_info {
> block_t total_valid_block_count; /* # of valid blocks */
> block_t discard_blks; /* discard command candidats */
> block_t last_valid_block_count; /* for recovery */
> - block_t reserved_blocks; /* configurable reserved blocks */
> + block_t target_reserved_blocks; /* configurable reserved blocks */
> + block_t current_reserved_blocks; /* current reserved blocks */
>
> u32 s_next_generation; /* for NFS support */
>
> @@ -1557,7 +1558,8 @@ static inline int inc_valid_block_count(struct f2fs_sb_info *sbi,
>
> spin_lock(&sbi->stat_lock);
> sbi->total_valid_block_count += (block_t)(*count);
> - avail_user_block_count = sbi->user_block_count - sbi->reserved_blocks;
> + avail_user_block_count = sbi->user_block_count -
> + sbi->current_reserved_blocks;
> if (unlikely(sbi->total_valid_block_count > avail_user_block_count)) {
> diff = sbi->total_valid_block_count - avail_user_block_count;
> *count -= diff;
> @@ -1591,6 +1593,10 @@ static inline void dec_valid_block_count(struct f2fs_sb_info *sbi,
> f2fs_bug_on(sbi, sbi->total_valid_block_count < (block_t) count);
> f2fs_bug_on(sbi, inode->i_blocks < sectors);
> sbi->total_valid_block_count -= (block_t)count;
> + if (sbi->target_reserved_blocks &&
> + sbi->current_reserved_blocks < sbi->target_reserved_blocks)
> + sbi->current_reserved_blocks = min(sbi->target_reserved_blocks,
> + sbi->current_reserved_blocks + count);
> spin_unlock(&sbi->stat_lock);
> f2fs_i_blocks_write(inode, count, false, true);
> }
> @@ -1737,7 +1743,7 @@ static inline int inc_valid_node_count(struct f2fs_sb_info *sbi,
> spin_lock(&sbi->stat_lock);
>
> valid_block_count = sbi->total_valid_block_count + 1;
> - if (unlikely(valid_block_count + sbi->reserved_blocks >
> + if (unlikely(valid_block_count + sbi->current_reserved_blocks >
> sbi->user_block_count)) {
> spin_unlock(&sbi->stat_lock);
> goto enospc;
> @@ -1780,6 +1786,9 @@ static inline void dec_valid_node_count(struct f2fs_sb_info *sbi,
>
> sbi->total_valid_node_count--;
> sbi->total_valid_block_count--;
> + if (sbi->target_reserved_blocks &&
> + sbi->current_reserved_blocks < sbi->target_reserved_blocks)
> + sbi->current_reserved_blocks++;
>
> spin_unlock(&sbi->stat_lock);
>
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index 213d2c1..c682978 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -987,7 +987,7 @@ static int f2fs_statfs(struct dentry *dentry, struct kstatfs *buf)
> buf->f_blocks = total_count - start_count;
> buf->f_bfree = user_block_count - valid_user_blocks(sbi) + ovp_count;
> buf->f_bavail = user_block_count - valid_user_blocks(sbi) -
> - sbi->reserved_blocks;
> + sbi->current_reserved_blocks;
>
> avail_node_count = sbi->total_node_count - F2FS_RESERVED_NODE_NUM;
>
> @@ -2457,7 +2457,8 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
> sbi->total_valid_block_count =
> le64_to_cpu(sbi->ckpt->valid_block_count);
> sbi->last_valid_block_count = sbi->total_valid_block_count;
> - sbi->reserved_blocks = 0;
> + sbi->target_reserved_blocks = 0;
> + sbi->current_reserved_blocks = 0;
>
> for (i = 0; i < NR_INODE_TYPE; i++) {
> INIT_LIST_HEAD(&sbi->inode_list[i]);
> diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
> index e09e59c..568e32f 100644
> --- a/fs/f2fs/sysfs.c
> +++ b/fs/f2fs/sysfs.c
> @@ -30,7 +30,7 @@ enum {
> FAULT_INFO_RATE, /* struct f2fs_fault_info */
> FAULT_INFO_TYPE, /* struct f2fs_fault_info */
> #endif
> - RESERVED_BLOCKS,
> + RESERVED_BLOCKS, /* struct f2fs_sb_info */
> };
>
> struct f2fs_attr {
> @@ -114,6 +114,12 @@ static ssize_t features_show(struct f2fs_attr *a,
> return len;
> }
>
> +static ssize_t current_reserved_blocks_show(struct f2fs_attr *a,
> + struct f2fs_sb_info *sbi, char *buf)
> +{
> + return snprintf(buf, PAGE_SIZE, "%u\n", sbi->current_reserved_blocks);
> +}
> +
> static ssize_t f2fs_sbi_show(struct f2fs_attr *a,
> struct f2fs_sb_info *sbi, char *buf)
> {
> @@ -153,12 +159,13 @@ static ssize_t f2fs_sbi_store(struct f2fs_attr *a,
> #endif
> if (a->struct_type == RESERVED_BLOCKS) {
> spin_lock(&sbi->stat_lock);
> - if ((unsigned long)sbi->total_valid_block_count + t >
> - (unsigned long)sbi->user_block_count) {
> + if (t > (unsigned long)sbi->user_block_count) {
> spin_unlock(&sbi->stat_lock);
> return -EINVAL;
> }
> *ui = t;
> + sbi->current_reserved_blocks = min(sbi->target_reserved_blocks,
> + sbi->user_block_count - valid_user_blocks(sbi));
> spin_unlock(&sbi->stat_lock);
> return count;
> }
> @@ -272,7 +279,8 @@ static ssize_t f2fs_feature_show(struct f2fs_attr *a,
> F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, reclaim_segments, rec_prefree_segments);
> F2FS_RW_ATTR(DCC_INFO, discard_cmd_control, max_small_discards, max_discards);
> F2FS_RW_ATTR(DCC_INFO, discard_cmd_control, discard_granularity, discard_granularity);
> -F2FS_RW_ATTR(RESERVED_BLOCKS, f2fs_sb_info, reserved_blocks, reserved_blocks);
> +F2FS_RW_ATTR(RESERVED_BLOCKS, f2fs_sb_info, target_reserved_blocks,
> + target_reserved_blocks);
> F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, batched_trim_sections, trim_sections);
> F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, ipu_policy, ipu_policy);
> F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, min_ipu_util, min_ipu_util);
> @@ -293,6 +301,7 @@ static ssize_t f2fs_feature_show(struct f2fs_attr *a,
> F2FS_GENERAL_RO_ATTR(dirty_segments);
> F2FS_GENERAL_RO_ATTR(lifetime_write_kbytes);
> F2FS_GENERAL_RO_ATTR(features);
> +F2FS_GENERAL_RO_ATTR(current_reserved_blocks);
>
> #ifdef CONFIG_F2FS_FS_ENCRYPTION
> F2FS_FEATURE_RO_ATTR(encryption, FEAT_CRYPTO);
> @@ -337,7 +346,8 @@ static ssize_t f2fs_feature_show(struct f2fs_attr *a,
> ATTR_LIST(dirty_segments),
> ATTR_LIST(lifetime_write_kbytes),
> ATTR_LIST(features),
> - ATTR_LIST(reserved_blocks),
> + ATTR_LIST(target_reserved_blocks),
> + ATTR_LIST(current_reserved_blocks),
> NULL,
> };
>
>