[PATCH] f2fs: support soft block reservation

From: Yunlong Song
Date: Wed Aug 16 2017 - 11:01:56 EST


It supports to extend reserved_blocks sysfs interface to be soft
threshold, which allows user configure it exceeding current available
user space.

Signed-off-by: Yunlong Song <yunlong.song@xxxxxxxxxx>
Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx>
---
Documentation/ABI/testing/sysfs-fs-f2fs | 3 ++-
fs/f2fs/f2fs.h | 12 ++++++++++--
fs/f2fs/super.c | 3 ++-
fs/f2fs/sysfs.c | 16 ++++++++++++++--
4 files changed, 28 insertions(+), 6 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs
index 11b7f4ebea7c..45c3d92f77c8 100644
--- a/Documentation/ABI/testing/sysfs-fs-f2fs
+++ b/Documentation/ABI/testing/sysfs-fs-f2fs
@@ -138,7 +138,8 @@ What: /sys/fs/f2fs/<disk>/reserved_blocks
Date: June 2017
Contact: "Chao Yu" <yuchao0@xxxxxxxxxx>
Description:
- Controls current reserved blocks in system.
+ Controls current reserved blocks in system, the threshold
+ is soft, it could exceed current avaible user space.

What: /sys/fs/f2fs/<disk>/gc_urgent
Date: August 2017
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 336021b9b93e..a7b2d257e8ee 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1046,6 +1046,7 @@ 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 current_reserved_blocks; /* current reserved blocks */

u32 s_next_generation; /* for NFS support */

@@ -1520,7 +1521,8 @@ 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;
@@ -1554,6 +1556,9 @@ 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->reserved_blocks)
+ sbi->current_reserved_blocks = min(sbi->reserved_blocks,
+ sbi->current_reserved_blocks + count);
spin_unlock(&sbi->stat_lock);
f2fs_i_blocks_write(inode, count, false, true);
}
@@ -1700,7 +1705,7 @@ 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;
@@ -1743,6 +1748,9 @@ static inline void dec_valid_node_count(struct f2fs_sb_info *sbi,

sbi->total_valid_node_count--;
sbi->total_valid_block_count--;
+ if (sbi->reserved_blocks)
+ sbi->current_reserved_blocks = min(sbi->reserved_blocks,
+ sbi->current_reserved_blocks + 1);

spin_unlock(&sbi->stat_lock);

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 4c1bdcb94133..036f083bbf56 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->current_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->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 4bcaa9059026..3173a272fe7c 100644
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -104,12 +104,23 @@ static ssize_t features_show(struct f2fs_attr *a,
return len;
}

+static ssize_t f2fs_reserved_blocks_show(struct f2fs_attr *a,
+ struct f2fs_sb_info *sbi, char *buf)
+{
+ return snprintf(buf, PAGE_SIZE,
+ "expected: %u\ncurrent: %u\n",
+ sbi->reserved_blocks, sbi->current_reserved_blocks);
+}
+
static ssize_t f2fs_sbi_show(struct f2fs_attr *a,
struct f2fs_sb_info *sbi, char *buf)
{
unsigned char *ptr = NULL;
unsigned int *ui;

+ if (a->struct_type == RESERVED_BLOCKS)
+ return f2fs_reserved_blocks_show(a, sbi, buf);
+
ptr = __struct_ptr(sbi, a->struct_type);
if (!ptr)
return -EINVAL;
@@ -143,12 +154,13 @@ 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->reserved_blocks,
+ sbi->user_block_count - valid_user_blocks(sbi));
spin_unlock(&sbi->stat_lock);
return count;
}
--
2.13.1.388.g69e6b9b4f4a9



On 2017/8/18 18:05, Yunlong Song wrote:
> ping...
>
> On 2017/8/15 12:08, Yunlong Song wrote:
>> ping...
>>
>> 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@xxxxxxxxxx>
>>> ---
>>> 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@xxxxxxxxxx>
>>> Description:
>>> Controls sleep time of GC urgent mode
>>> +
>>> +What: /sys/fs/f2fs/<disk>/cur_reserved_blocks
>>> +Date: August 2017
>>> +Contact: "Yunlong Song" <yunlong.song@xxxxxxxxxx>
>>> +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,
>>> };
>>
>