Re: [PATCH v2] f2fs: introduce cur_reserved_blocks in sysfs
From: Yunlong Song
Date: Wed Oct 25 2017 - 06:06:41 EST
Hi, Chao,
ping...
Please see the review comment below. And the change is already in the v3
patch.
On 2017/8/18 23:16, Yunlong Song wrote:
I send a v3 patch, please review, and the main difference is shown below.
On 2017/8/18 18:20, Chao Yu wrote:
Hi Yunlong,
IMO, we don't need additional sysfs entry, how about changing a bit
as below?
>From 3fc8206871fe457859f1537c9dc8918b45f14601 Mon Sep 17 00:00:00 2001
From: Yunlong Song <yunlong.song@xxxxxxxxxx>
Date: Wed, 16 Aug 2017 23:01:56 +0800
Subject: [PATCH] f2fs: support soft block reservation
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)
Add sbi->reserved_blocks != sbi->cur_reserved_blocks check
+ 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);
change to sbi->cur_reserved_blocks++;
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));
This is not safe for support system's activation, since the user
available space can be suddenly zero!
So I change this to only admit t < sbi->cur_reserved_blocks then
change its value.
spin_unlock(&sbi->stat_lock);
return count;
}
--
Thanks,
Yunlong Song