f2fs: introduce reserved_blocks in sysfs

In this patch, we add a new sysfs interface, with it, we can control
number of reserved blocks in system which could not be used by user,
it enable f2fs to let user to configure for adjusting over-provision
ratio dynamically instead of changing it by mkfs.

So we can expect it will help to reserve more free space for relieving
GC in both filesystem and flash device.

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 b09108811ff1f82520df46e218710ff39497019a..84c606fb3ca4dff45bbd59af27de49d6d86884ca 100644 (file)
--- a/Documentation/ABI/testing/sysfs-fs-f2fs
+++ b/Documentation/ABI/testing/sysfs-fs-f2fs
@@ -124,3 +124,9 @@ Date:               May 2016
 Contact:       "Sheng Yong" <shengyong1@huawei.com>
 Description:
                 Controls the injection type.
+
+What:          /sys/fs/f2fs/<disk>/reserved_blocks
+Date:          June 2017
+Contact:       "Chao Yu" <yuchao0@huawei.com>
+Description:
+                Controls current reserved blocks in system.

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index c27a6264d9bf2bf3d6c6ce2f35e1f9e86f0c7449..e15d55ccc4bc26cac12b2deb6384af2f27f4e1f2 100644 (file)
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -966,6 +966,8 @@ 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 */
+
        u32 s_next_generation;                  /* for NFS support */
 
        /* # of pages, see count_type */
@@ -1376,6 +1378,7 @@ static inline bool inc_valid_block_count(struct f2fs_sb_info *sbi,
                                 struct inode *inode, blkcnt_t *count)
 {
        blkcnt_t diff;
+       block_t avail_user_block_count;
 
 #ifdef CONFIG_F2FS_FAULT_INJECTION
        if (time_to_inject(sbi, FAULT_BLOCK)) {
@@ -1391,10 +1394,11 @@ static inline bool inc_valid_block_count(struct f2fs_sb_info *sbi,
 
        spin_lock(&sbi->stat_lock);
        sbi->total_valid_block_count += (block_t)(*count);
-       if (unlikely(sbi->total_valid_block_count > sbi->user_block_count)) {
-               diff = sbi->total_valid_block_count - sbi->user_block_count;
+       avail_user_block_count = sbi->user_block_count - sbi->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;
-               sbi->total_valid_block_count = sbi->user_block_count;
+               sbi->total_valid_block_count = avail_user_block_count;
                if (!*count) {
                        spin_unlock(&sbi->stat_lock);
                        percpu_counter_sub(&sbi->alloc_valid_block_count, diff);
@@ -1556,7 +1560,8 @@ static inline bool 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->user_block_count)) {
+       if (unlikely(valid_block_count + sbi->reserved_blocks >
+                                               sbi->user_block_count)) {
                spin_unlock(&sbi->stat_lock);
                return false;
        }

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 3da6fb276f8b6cd5dc564d87b01852a1a228419b..c45bac6f1795827cc7f2bc4b89ce7fe26e4fb73e 100644 (file)
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -691,7 +691,8 @@ 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);
+       buf->f_bavail = user_block_count - valid_user_blocks(sbi) -
+                                               sbi->reserved_blocks;
 
        avail_node_count = sbi->total_node_count - F2FS_RESERVED_NODE_NUM;
 
@@ -1768,6 +1769,7 @@ try_onemore:
        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;
 
        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 714a3e47bbe8d17cc72e39520a725ebcf44120ec..9adc202fcd6f76ca4e0f0b16d5b4aedd6e2e4e9c 100644 (file)
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -30,6 +30,7 @@ enum {
        FAULT_INFO_RATE,        /* struct f2fs_fault_info */
        FAULT_INFO_TYPE,        /* struct f2fs_fault_info */
 #endif
+       RESERVED_BLOCKS,
 };
 
 struct f2fs_attr {
@@ -51,7 +52,7 @@ static unsigned char *__struct_ptr(struct f2fs_sb_info *sbi, int struct_type)
                return (unsigned char *)SM_I(sbi)->dcc_info;
        else if (struct_type == NM_INFO)
                return (unsigned char *)NM_I(sbi);
-       else if (struct_type == F2FS_SBI)
+       else if (struct_type == F2FS_SBI || struct_type == RESERVED_BLOCKS)
                return (unsigned char *)sbi;
 #ifdef CONFIG_F2FS_FAULT_INJECTION
        else if (struct_type == FAULT_INFO_RATE ||
@@ -111,6 +112,17 @@ static ssize_t f2fs_sbi_store(struct f2fs_attr *a,
        if (a->struct_type == FAULT_INFO_TYPE && t >= (1 << FAULT_MAX))
                return -EINVAL;
 #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;
+               spin_unlock(&sbi->stat_lock);
+               return count;
+       }
        *ui = t;
        return count;
 }
@@ -165,6 +177,7 @@ F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_no_gc_sleep_time, no_gc_sleep_time);
 F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_idle, gc_idle);
 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(RESERVED_BLOCKS, f2fs_sb_info, reserved_blocks, 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);
@@ -208,6 +221,7 @@ static struct attribute *f2fs_attrs[] = {
        ATTR_LIST(inject_type),
 #endif
        ATTR_LIST(lifetime_write_kbytes),
+       ATTR_LIST(reserved_blocks),
        NULL,
 };