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. This patch also introduces a new sysfs interface called
current_reserved_blocks, which shows the current blocks that have
already been reserved.

Signed-off-by: Yunlong Song <yunlong.song@huawei.com>
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs
index 11b7f4ebea7c4b6a04d2ce3894ff1a8d9907e60a..7562b0d42105ecb41f5af57be0de867abdd6db2e 100644 (file)
--- a/Documentation/ABI/testing/sysfs-fs-f2fs
+++ b/Documentation/ABI/testing/sysfs-fs-f2fs
@@ -138,7 +138,18 @@ What:              /sys/fs/f2fs/<disk>/reserved_blocks
 Date:          June 2017
 Contact:       "Chao Yu" <yuchao0@huawei.com>
 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@huawei.com>
+Contact:       "Chao Yu" <yuchao0@huawei.com>
+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 13a96b8aa2d7f95d053232003fdfca08c57fde51..5ed40fbd1a367e93f7db1207c1314dc552e9c128 100644 (file)
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1082,6 +1082,7 @@ 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 */
 
@@ -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->reserved_blocks &&
+               sbi->current_reserved_blocks < 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);
 }
@@ -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->reserved_blocks &&
+               sbi->current_reserved_blocks < sbi->reserved_blocks)
+               sbi->current_reserved_blocks++;
 
        spin_unlock(&sbi->stat_lock);
 

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 213d2c1e57592d09b9fdb49faf7007781214523e..dab1fedf7148dee7b83e517131409b6446414fa5 100644 (file)
--- 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;
 
@@ -2458,6 +2458,7 @@ 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 e09e59cc678a1da0fc7fd52bcebdca16e8ea99d2..4166ac74e837006c9695337eabd6fb57933862b3 100644 (file)
--- 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->reserved_blocks,
+                               sbi->user_block_count - valid_user_blocks(sbi));
                spin_unlock(&sbi->stat_lock);
                return count;
        }
@@ -293,6 +300,7 @@ F2FS_RW_ATTR(FAULT_INFO_TYPE, f2fs_fault_info, inject_type, inject_type);
 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);
@@ -338,6 +346,7 @@ static struct attribute *f2fs_attrs[] = {
        ATTR_LIST(lifetime_write_kbytes),
        ATTR_LIST(features),
        ATTR_LIST(reserved_blocks),
+       ATTR_LIST(current_reserved_blocks),
        NULL,
 };