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Message-ID: <20180104065158.GB54234@jaegeuk-macbookpro.roam.corp.google.com>
Date: Wed, 3 Jan 2018 22:51:58 -0800
From: Jaegeuk Kim <jaegeuk@...nel.org>
To: linux-kernel@...r.kernel.org,
linux-f2fs-devel@...ts.sourceforge.net
Subject: Re: [PATCH 2/2 v2] f2fs: add reserved blocks for root user
This patch allows root to reserve some blocks via mount option.
"-o reserve_root=N" means N x 4KB-sized blocks for root only.
Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
---
Change log from v1:
- handle remount case to limit reserve_root=%u
fs/f2fs/f2fs.h | 20 ++++++++++++++++----
fs/f2fs/super.c | 34 +++++++++++++++++++++++++++++++++-
fs/f2fs/sysfs.c | 3 ++-
3 files changed, 51 insertions(+), 6 deletions(-)
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index a52de99a34b9..4d255aac49bb 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -95,6 +95,7 @@ extern char *fault_name[FAULT_MAX];
#define F2FS_MOUNT_PRJQUOTA 0x00200000
#define F2FS_MOUNT_QUOTA 0x00400000
#define F2FS_MOUNT_INLINE_XATTR_SIZE 0x00800000
+#define F2FS_MOUNT_RESERVE_ROOT 0x01000000
#define clear_opt(sbi, option) ((sbi)->mount_opt.opt &= ~F2FS_MOUNT_##option)
#define set_opt(sbi, option) ((sbi)->mount_opt.opt |= F2FS_MOUNT_##option)
@@ -1109,6 +1110,7 @@ struct f2fs_sb_info {
block_t last_valid_block_count; /* for recovery */
block_t reserved_blocks; /* configurable reserved blocks */
block_t current_reserved_blocks; /* current reserved blocks */
+ block_t root_reserved_blocks; /* root reserved blocks */
unsigned int nquota_files; /* # of quota sysfile */
@@ -1590,11 +1592,17 @@ static inline int inc_valid_block_count(struct f2fs_sb_info *sbi,
sbi->total_valid_block_count += (block_t)(*count);
avail_user_block_count = sbi->user_block_count -
sbi->current_reserved_blocks;
+
+ if (!(test_opt(sbi, RESERVE_ROOT) && capable(CAP_SYS_RESOURCE)))
+ avail_user_block_count -= sbi->root_reserved_blocks;
+
if (unlikely(sbi->total_valid_block_count > avail_user_block_count)) {
diff = sbi->total_valid_block_count - avail_user_block_count;
+ if (diff > *count)
+ diff = *count;
*count -= diff;
release = diff;
- sbi->total_valid_block_count = avail_user_block_count;
+ sbi->total_valid_block_count -= diff;
if (!*count) {
spin_unlock(&sbi->stat_lock);
percpu_counter_sub(&sbi->alloc_valid_block_count, diff);
@@ -1783,9 +1791,13 @@ 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->current_reserved_blocks >
- sbi->user_block_count)) {
+ valid_block_count = sbi->total_valid_block_count +
+ sbi->current_reserved_blocks + 1;
+
+ if (!(test_opt(sbi, RESERVE_ROOT) && capable(CAP_SYS_RESOURCE)))
+ valid_block_count += sbi->root_reserved_blocks;
+
+ if (unlikely(valid_block_count > sbi->user_block_count)) {
spin_unlock(&sbi->stat_lock);
goto enospc;
}
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index f1300cda6bfd..f828a3ea3c9a 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -107,6 +107,7 @@ enum {
Opt_noextent_cache,
Opt_noinline_data,
Opt_data_flush,
+ Opt_reserve_root,
Opt_mode,
Opt_io_size_bits,
Opt_fault_injection,
@@ -157,6 +158,7 @@ static match_table_t f2fs_tokens = {
{Opt_noextent_cache, "noextent_cache"},
{Opt_noinline_data, "noinline_data"},
{Opt_data_flush, "data_flush"},
+ {Opt_reserve_root, "reserve_root=%u"},
{Opt_mode, "mode=%s"},
{Opt_io_size_bits, "io_bits=%u"},
{Opt_fault_injection, "fault_injection=%u"},
@@ -191,6 +193,19 @@ void f2fs_msg(struct super_block *sb, const char *level, const char *fmt, ...)
va_end(args);
}
+static inline void limit_reserve_root(struct f2fs_sb_info *sbi)
+{
+ block_t limit = (sbi->user_block_count << 1) / 1000;
+
+ /* limit is 0.2% */
+ if (test_opt(sbi, RESERVE_ROOT) && sbi->root_reserved_blocks > limit) {
+ sbi->root_reserved_blocks = limit;
+ f2fs_msg(sbi->sb, KERN_INFO,
+ "Reduce reserved blocks for root = %u",
+ sbi->root_reserved_blocks);
+ }
+}
+
static void init_once(void *foo)
{
struct f2fs_inode_info *fi = (struct f2fs_inode_info *) foo;
@@ -488,6 +503,18 @@ static int parse_options(struct super_block *sb, char *options)
case Opt_data_flush:
set_opt(sbi, DATA_FLUSH);
break;
+ case Opt_reserve_root:
+ if (args->from && match_int(args, &arg))
+ return -EINVAL;
+ if (test_opt(sbi, RESERVE_ROOT)) {
+ f2fs_msg(sb, KERN_INFO,
+ "Preserve previous reserve_root=%u",
+ sbi->root_reserved_blocks);
+ } else {
+ sbi->root_reserved_blocks = arg;
+ set_opt(sbi, RESERVE_ROOT);
+ }
+ break;
case Opt_mode:
name = match_strdup(&args[0]);
@@ -1006,7 +1033,7 @@ 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) -
sbi->current_reserved_blocks;
- buf->f_bavail = buf->f_bfree;
+ buf->f_bavail = buf->f_bfree - sbi->root_reserved_blocks;
avail_node_count = sbi->total_node_count - sbi->nquota_files -
F2FS_RESERVED_NODE_NUM;
@@ -1135,6 +1162,9 @@ static int f2fs_show_options(struct seq_file *seq, struct dentry *root)
else if (test_opt(sbi, LFS))
seq_puts(seq, "lfs");
seq_printf(seq, ",active_logs=%u", sbi->active_logs);
+ if (test_opt(sbi, RESERVE_ROOT))
+ seq_printf(seq, ",reserve_root=%u",
+ sbi->root_reserved_blocks);
if (F2FS_IO_SIZE_BITS(sbi))
seq_printf(seq, ",io_size=%uKB", F2FS_IO_SIZE_KB(sbi));
#ifdef CONFIG_F2FS_FAULT_INJECTION
@@ -1333,6 +1363,7 @@ static int f2fs_remount(struct super_block *sb, int *flags, char *data)
sb->s_flags = (sb->s_flags & ~SB_POSIXACL) |
(test_opt(sbi, POSIX_ACL) ? SB_POSIXACL : 0);
+ limit_reserve_root(sbi);
return 0;
restore_gc:
if (need_restart_gc) {
@@ -2569,6 +2600,7 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
sbi->last_valid_block_count = sbi->total_valid_block_count;
sbi->reserved_blocks = 0;
sbi->current_reserved_blocks = 0;
+ limit_reserve_root(sbi);
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 7e15cbc5b8e1..41887e6ec1b3 100644
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -162,7 +162,8 @@ static ssize_t f2fs_sbi_store(struct f2fs_attr *a,
#endif
if (a->struct_type == RESERVED_BLOCKS) {
spin_lock(&sbi->stat_lock);
- if (t > (unsigned long)sbi->user_block_count) {
+ if (t > (unsigned long)(sbi->user_block_count -
+ sbi->root_reserved_blocks)) {
spin_unlock(&sbi->stat_lock);
return -EINVAL;
}
--
2.15.0.531.g2ccb3012c9-goog
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