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SubjectRe: [PATCH v2] f2fs: introduce cur_reserved_blocks in sysfs
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On 2017/8/11 19:43, Yunlong Song wrote:
> In this patch, we add a new sysfs interface, we can use it to gradually achieve
> the reserved_blocks finally, even when reserved_blocks is initially set over
> user_block_count - total_valid_block_count. This is very useful, especially when
> we upgrade kernel with new reserved_blocks value, but old disk image unluckily has
> user_block_count - total_valid_block_count smaller than the desired reserved_blocks.
> With this patch, f2fs can try its best to reserve space and get close to the
> reserved_blocks, and the current value of achieved reserved_blocks can be shown
> in real time.
>
> To ensure there is enough space for supporting system's activation, we safely
> increase cur_reserved_blocks in dev_valid_block(,node)_count to only take up the
> blocks which are just obsoleted.
>
> Signed-off-by: Yunlong Song <yunlong.song@huawei.com>
> ---
> Documentation/ABI/testing/sysfs-fs-f2fs | 6 ++++++
> fs/f2fs/f2fs.h | 9 +++++++--
> fs/f2fs/super.c | 3 ++-
> fs/f2fs/sysfs.c | 15 ++++++++++-----
> 4 files changed, 25 insertions(+), 8 deletions(-)
>
> diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs
> index 11b7f4e..bdbb9f3 100644
> --- a/Documentation/ABI/testing/sysfs-fs-f2fs
> +++ b/Documentation/ABI/testing/sysfs-fs-f2fs
> @@ -151,3 +151,9 @@ Date: August 2017
> Contact: "Jaegeuk Kim" <jaegeuk@kernel.org>
> Description:
> Controls sleep time of GC urgent mode
> +
> +What: /sys/fs/f2fs/<disk>/cur_reserved_blocks
> +Date: August 2017
> +Contact: "Yunlong Song" <yunlong.song@huawei.com>
> +Description:
> + Shows current reserved blocks in system.
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index 2f20b6b..62d7343 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -1041,6 +1041,7 @@ struct f2fs_sb_info {
> block_t discard_blks; /* discard command candidats */
> block_t last_valid_block_count; /* for recovery */
> block_t reserved_blocks; /* configurable reserved blocks */
> + block_t cur_reserved_blocks; /* current reserved blocks */
>
> u32 s_next_generation; /* for NFS support */
>
> @@ -1515,7 +1516,7 @@ 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->cur_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;
> @@ -1549,6 +1550,8 @@ 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;
> + sbi->cur_reserved_blocks = min(sbi->reserved_blocks,
> + sbi->cur_reserved_blocks + count);
> spin_unlock(&sbi->stat_lock);
> f2fs_i_blocks_write(inode, count, false, true);
> }
> @@ -1695,7 +1698,7 @@ 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->cur_reserved_blocks >
> sbi->user_block_count)) {
> spin_unlock(&sbi->stat_lock);
> goto enospc;
> @@ -1738,6 +1741,8 @@ static inline void dec_valid_node_count(struct f2fs_sb_info *sbi,
>
> sbi->total_valid_node_count--;
> sbi->total_valid_block_count--;
> + sbi->cur_reserved_blocks = min(sbi->reserved_blocks,
> + sbi->cur_reserved_blocks + 1);
>
> spin_unlock(&sbi->stat_lock);
>
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index 4c1bdcb..16a805f 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -957,7 +957,7 @@ 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->cur_reserved_blocks;
>
> avail_node_count = sbi->total_node_count - F2FS_RESERVED_NODE_NUM;
>
> @@ -2411,6 +2411,7 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
> le64_to_cpu(sbi->ckpt->valid_block_count);
> sbi->last_valid_block_count = sbi->total_valid_block_count;
> sbi->reserved_blocks = 0;
> + sbi->cur_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 a1be5ac..03f9d3d 100644
> --- a/fs/f2fs/sysfs.c
> +++ b/fs/f2fs/sysfs.c
> @@ -76,6 +76,12 @@ static ssize_t lifetime_write_kbytes_show(struct f2fs_attr *a,
> BD_PART_WRITTEN(sbi)));
> }
>
> +static ssize_t cur_reserved_blocks_show(struct f2fs_attr *a,
> + struct f2fs_sb_info *sbi, char *buf)
> +{
> + return snprintf(buf, PAGE_SIZE, "%u\n", sbi->cur_reserved_blocks);
> +}
> +
> static ssize_t features_show(struct f2fs_attr *a,
> struct f2fs_sb_info *sbi, char *buf)
> {
> @@ -143,12 +149,9 @@ 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) {
> - spin_unlock(&sbi->stat_lock);
> - return -EINVAL;
> - }
> *ui = t;
> + if (t < sbi->cur_reserved_blocks)
> + sbi->cur_reserved_blocks = t;
> spin_unlock(&sbi->stat_lock);
> return count;
> }
> @@ -274,6 +277,7 @@ static ssize_t f2fs_feature_show(struct f2fs_attr *a,
> #endif
> F2FS_GENERAL_RO_ATTR(lifetime_write_kbytes);
> F2FS_GENERAL_RO_ATTR(features);
> +F2FS_GENERAL_RO_ATTR(cur_reserved_blocks);
>
> #ifdef CONFIG_F2FS_FS_ENCRYPTION
> F2FS_FEATURE_RO_ATTR(encryption, FEAT_CRYPTO);
> @@ -317,6 +321,7 @@ static ssize_t f2fs_feature_show(struct f2fs_attr *a,
> ATTR_LIST(lifetime_write_kbytes),
> ATTR_LIST(features),
> ATTR_LIST(reserved_blocks),
> + ATTR_LIST(cur_reserved_blocks),
> NULL,
> };
>

--
Thanks,
Yunlong Song


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