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,
};
