Re: [PATCH v4] f2fs: support soft block reservation

From: Jaegeuk Kim
Date: Fri Oct 27 2017 - 07:06:38 EST


On 10/27, Chao Yu wrote:
> 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?

Good catch. It makes sense to keep the entry name. :)

Thanks,

>
> 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,
> > };
> >
> >