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Message-ID: <8a304530-83a9-4fb0-947b-49b9e33fb19a@vivo.com>
Date: Wed, 6 Aug 2025 08:56:32 +0000
From: Chunhai Guo <guochunhai@...o.com>
To: Jaegeuk Kim <jaegeuk@...nel.org>, Chunhai Guo <guochunhai@...o.com>
CC: Chao Yu <chao@...nel.org>, "linux-f2fs-devel@...ts.sourceforge.net"
<linux-f2fs-devel@...ts.sourceforge.net>, "linux-kernel@...r.kernel.org"
<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v4] f2fs: add reserved nodes for privileged users
在 8/5/2025 10:38 AM, Jaegeuk Kim 写道:
> On 07/31, Chunhai Guo wrote:
>> 在 7/31/2025 4:46 PM, Chao Yu 写道:
>>> On 7/31/25 15:57, Chunhai Guo wrote:
>>>> This patch allows privileged users to reserve nodes via the
>>>> 'reserve_node' mount option, which is similar to the existing
>>>> 'reserve_root' option.
>>>>
>>>> "-o reserve_node=<N>" means <N> nodes are reserved for privileged
>>>> users only.
>>>>
>>>> Signed-off-by: Chunhai Guo <guochunhai@...o.com>
>>>> ---
>>>> v3->v4: Rebase this patch on https://lore.kernel.org/linux-f2fs-devel/20250731060338.1136086-1-chao@kernel.org
>>>> v2->v3: Apply Chao's suggestion from v2.
>>>> v1->v2: Add two missing handling parts.
>>>> v1: https://lore.kernel.org/linux-f2fs-devel/20250729095238.607433-1-guochunhai@vivo.com/
>>>> ---
>>>> Documentation/filesystems/f2fs.rst | 9 ++++---
>>>> fs/f2fs/f2fs.h | 14 +++++++---
>>>> fs/f2fs/super.c | 43 +++++++++++++++++++++++++-----
>>>> 3 files changed, 52 insertions(+), 14 deletions(-)
>>>>
>>>> diff --git a/Documentation/filesystems/f2fs.rst b/Documentation/filesystems/f2fs.rst
>>>> index 03b1efa6d3b2..95dbcd7ac9a8 100644
>>>> --- a/Documentation/filesystems/f2fs.rst
>>>> +++ b/Documentation/filesystems/f2fs.rst
>>>> @@ -173,9 +173,12 @@ data_flush Enable data flushing before checkpoint in order to
>>>> persist data of regular and symlink.
>>>> reserve_root=%d Support configuring reserved space which is used for
>>>> allocation from a privileged user with specified uid or
>>>> - gid, unit: 4KB, the default limit is 0.2% of user blocks.
>>>> -resuid=%d The user ID which may use the reserved blocks.
>>>> -resgid=%d The group ID which may use the reserved blocks.
>>>> + gid, unit: 4KB, the default limit is 12.5% of user blocks.
>>>> +reserve_node=%d Support configuring reserved nodes which are used for
>>>> + allocation from a privileged user with specified uid or
>>>> + gid, the default limit is 12.5% of all nodes.
>>>> +resuid=%d The user ID which may use the reserved blocks and nodes.
>>>> +resgid=%d The group ID which may use the reserved blocks and nodes.
>>>> fault_injection=%d Enable fault injection in all supported types with
>>>> specified injection rate.
>>>> fault_type=%d Support configuring fault injection type, should be
>>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>>>> index eb372af22edc..b9676ef16246 100644
>>>> --- a/fs/f2fs/f2fs.h
>>>> +++ b/fs/f2fs/f2fs.h
>>>> @@ -131,6 +131,7 @@ extern const char *f2fs_fault_name[FAULT_MAX];
>>>> * string rather than using the MS_LAZYTIME flag, so this must remain.
>>>> */
>>>> #define F2FS_MOUNT_LAZYTIME 0x40000000
>>>> +#define F2FS_MOUNT_RESERVE_NODE 0x80000000
>>>>
>>>> #define F2FS_OPTION(sbi) ((sbi)->mount_opt)
>>>> #define clear_opt(sbi, option) (F2FS_OPTION(sbi).opt &= ~F2FS_MOUNT_##option)
>>>> @@ -172,6 +173,7 @@ struct f2fs_rwsem {
>>>> struct f2fs_mount_info {
>>>> unsigned int opt;
>>>> block_t root_reserved_blocks; /* root reserved blocks */
>>>> + block_t root_reserved_nodes; /* root reserved nodes */
>>>> kuid_t s_resuid; /* reserved blocks for uid */
>>>> kgid_t s_resgid; /* reserved blocks for gid */
>>>> int active_logs; /* # of active logs */
>>>> @@ -2355,7 +2357,7 @@ static inline bool f2fs_has_xattr_block(unsigned int ofs)
>>>> return ofs == XATTR_NODE_OFFSET;
>>>> }
>>>>
>>>> -static inline bool __allow_reserved_blocks(struct f2fs_sb_info *sbi,
>>>> +static inline bool __allow_reserved_root(struct f2fs_sb_info *sbi,
>>>> struct inode *inode, bool cap)
>>>> {
>>>> if (!inode)
>>>> @@ -2380,7 +2382,7 @@ static inline unsigned int get_available_block_count(struct f2fs_sb_info *sbi,
>>>> avail_user_block_count = sbi->user_block_count -
>>>> sbi->current_reserved_blocks;
>>>>
>>>> - if (test_opt(sbi, RESERVE_ROOT) && !__allow_reserved_blocks(sbi, inode, cap))
>>>> + if (test_opt(sbi, RESERVE_ROOT) && !__allow_reserved_root(sbi, inode, cap))
>>>> avail_user_block_count -= F2FS_OPTION(sbi).root_reserved_blocks;
>>>>
>>>> if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED))) {
>>>> @@ -2738,7 +2740,7 @@ static inline int inc_valid_node_count(struct f2fs_sb_info *sbi,
>>>> struct inode *inode, bool is_inode)
>>>> {
>>>> block_t valid_block_count;
>>>> - unsigned int valid_node_count;
>>>> + unsigned int valid_node_count, avail_user_node_count;
>>>> unsigned int avail_user_block_count;
>>>> int err;
>>>>
>>>> @@ -2767,8 +2769,12 @@ static inline int inc_valid_node_count(struct f2fs_sb_info *sbi,
>>>> goto enospc;
>>>> }
>>>>
>>>> + avail_user_node_count = sbi->total_node_count - F2FS_RESERVED_NODE_NUM;
>>>> + if (test_opt(sbi, RESERVE_NODE) &&
>>>> + !__allow_reserved_root(sbi, inode, false))
>>> Chunhai,
>>>
>>> Do we need to pass cap=true to __allow_reserved_root()?
>>>
>>> In addition, do we need to change cap as well for below statement?
>>>
>>> avail_user_block_count = get_available_block_count(sbi, inode, false);
>>
>> Hi Jaegeuk,
>>
>>
>> Based on the description in commit a90a0884ac75 ("f2fs: check
>> cap_resource only for data blocks"), it seems that inode or node blocks
>> don't need to perform a check on the cap_resource. I'm not certain about
>> the reasoning behind this. Could you please help to clarify it?
> I don't quite remember as I had to fix the selinx issue long long time ago.
Got it. It seems hard to clarify the reason back then.
Thanks
>>
>> Thanks,
>>
>>> Thanks,
>>>
>>>> + avail_user_node_count -= F2FS_OPTION(sbi).root_reserved_nodes;
>>>> valid_node_count = sbi->total_valid_node_count + 1;
>>>> - if (unlikely(valid_node_count > sbi->total_node_count)) {
>>>> + if (unlikely(valid_node_count > avail_user_node_count)) {
>>>> spin_unlock(&sbi->stat_lock);
>>>> goto enospc;
>>>> }
>>>> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
>>>> index 30c038413040..a24e855a38ed 100644
>>>> --- a/fs/f2fs/super.c
>>>> +++ b/fs/f2fs/super.c
>>>> @@ -143,6 +143,7 @@ enum {
>>>> Opt_extent_cache,
>>>> Opt_data_flush,
>>>> Opt_reserve_root,
>>>> + Opt_reserve_node,
>>>> Opt_resgid,
>>>> Opt_resuid,
>>>> Opt_mode,
>>>> @@ -265,6 +266,7 @@ static const struct fs_parameter_spec f2fs_param_specs[] = {
>>>> fsparam_flag_no("extent_cache", Opt_extent_cache),
>>>> fsparam_flag("data_flush", Opt_data_flush),
>>>> fsparam_u32("reserve_root", Opt_reserve_root),
>>>> + fsparam_u32("reserve_node", Opt_reserve_node),
>>>> fsparam_gid("resgid", Opt_resgid),
>>>> fsparam_uid("resuid", Opt_resuid),
>>>> fsparam_enum("mode", Opt_mode, f2fs_param_mode),
>>>> @@ -336,6 +338,7 @@ static match_table_t f2fs_checkpoint_tokens = {
>>>> #define F2FS_SPEC_discard_unit (1 << 21)
>>>> #define F2FS_SPEC_memory_mode (1 << 22)
>>>> #define F2FS_SPEC_errors (1 << 23)
>>>> +#define F2FS_SPEC_reserve_node (1 << 24)
>>>>
>>>> struct f2fs_fs_context {
>>>> struct f2fs_mount_info info;
>>>> @@ -437,22 +440,30 @@ static void f2fs_destroy_casefold_cache(void) { }
>>>>
>>>> static inline void limit_reserve_root(struct f2fs_sb_info *sbi)
>>>> {
>>>> - block_t limit = min((sbi->user_block_count >> 3),
>>>> + block_t block_limit = min((sbi->user_block_count >> 3),
>>>> sbi->user_block_count - sbi->reserved_blocks);
>>>> + block_t node_limit = sbi->total_node_count >> 3;
>>>>
>>>> /* limit is 12.5% */
>>>> if (test_opt(sbi, RESERVE_ROOT) &&
>>>> - F2FS_OPTION(sbi).root_reserved_blocks > limit) {
>>>> - F2FS_OPTION(sbi).root_reserved_blocks = limit;
>>>> + F2FS_OPTION(sbi).root_reserved_blocks > block_limit) {
>>>> + F2FS_OPTION(sbi).root_reserved_blocks = block_limit;
>>>> f2fs_info(sbi, "Reduce reserved blocks for root = %u",
>>>> F2FS_OPTION(sbi).root_reserved_blocks);
>>>> }
>>>> - if (!test_opt(sbi, RESERVE_ROOT) &&
>>>> + if (test_opt(sbi, RESERVE_NODE) &&
>>>> + F2FS_OPTION(sbi).root_reserved_nodes > node_limit) {
>>>> + F2FS_OPTION(sbi).root_reserved_nodes = node_limit;
>>>> + f2fs_info(sbi, "Reduce reserved nodes for root = %u",
>>>> + F2FS_OPTION(sbi).root_reserved_nodes);
>>>> + }
>>>> + if (!test_opt(sbi, RESERVE_ROOT) && !test_opt(sbi, RESERVE_NODE) &&
>>>> (!uid_eq(F2FS_OPTION(sbi).s_resuid,
>>>> make_kuid(&init_user_ns, F2FS_DEF_RESUID)) ||
>>>> !gid_eq(F2FS_OPTION(sbi).s_resgid,
>>>> make_kgid(&init_user_ns, F2FS_DEF_RESGID))))
>>>> - f2fs_info(sbi, "Ignore s_resuid=%u, s_resgid=%u w/o reserve_root",
>>>> + f2fs_info(sbi, "Ignore s_resuid=%u, s_resgid=%u w/o reserve_root"
>>>> + " and reserve_node",
>>>> from_kuid_munged(&init_user_ns,
>>>> F2FS_OPTION(sbi).s_resuid),
>>>> from_kgid_munged(&init_user_ns,
>>>> @@ -841,6 +852,11 @@ static int f2fs_parse_param(struct fs_context *fc, struct fs_parameter *param)
>>>> F2FS_CTX_INFO(ctx).root_reserved_blocks = result.uint_32;
>>>> ctx->spec_mask |= F2FS_SPEC_reserve_root;
>>>> break;
>>>> + case Opt_reserve_node:
>>>> + ctx_set_opt(ctx, F2FS_MOUNT_RESERVE_NODE);
>>>> + F2FS_CTX_INFO(ctx).root_reserved_nodes = result.uint_32;
>>>> + ctx->spec_mask |= F2FS_SPEC_reserve_node;
>>>> + break;
>>>> case Opt_resuid:
>>>> F2FS_CTX_INFO(ctx).s_resuid = result.uid;
>>>> ctx->spec_mask |= F2FS_SPEC_resuid;
>>>> @@ -1424,6 +1440,14 @@ static int f2fs_check_opt_consistency(struct fs_context *fc,
>>>> ctx_clear_opt(ctx, F2FS_MOUNT_RESERVE_ROOT);
>>>> ctx->opt_mask &= ~F2FS_MOUNT_RESERVE_ROOT;
>>>> }
>>>> + if (test_opt(sbi, RESERVE_NODE) &&
>>>> + (ctx->opt_mask & F2FS_MOUNT_RESERVE_NODE) &&
>>>> + ctx_test_opt(ctx, F2FS_MOUNT_RESERVE_NODE)) {
>>>> + f2fs_info(sbi, "Preserve previous reserve_node=%u",
>>>> + F2FS_OPTION(sbi).root_reserved_nodes);
>>>> + ctx_clear_opt(ctx, F2FS_MOUNT_RESERVE_NODE);
>>>> + ctx->opt_mask &= ~F2FS_MOUNT_RESERVE_NODE;
>>>> + }
>>>>
>>>> err = f2fs_check_test_dummy_encryption(fc, sb);
>>>> if (err)
>>>> @@ -1623,6 +1647,9 @@ static void f2fs_apply_options(struct fs_context *fc, struct super_block *sb)
>>>> if (ctx->spec_mask & F2FS_SPEC_reserve_root)
>>>> F2FS_OPTION(sbi).root_reserved_blocks =
>>>> F2FS_CTX_INFO(ctx).root_reserved_blocks;
>>>> + if (ctx->spec_mask & F2FS_SPEC_reserve_node)
>>>> + F2FS_OPTION(sbi).root_reserved_nodes =
>>>> + F2FS_CTX_INFO(ctx).root_reserved_nodes;
>>>> if (ctx->spec_mask & F2FS_SPEC_resgid)
>>>> F2FS_OPTION(sbi).s_resgid = F2FS_CTX_INFO(ctx).s_resgid;
>>>> if (ctx->spec_mask & F2FS_SPEC_resuid)
>>>> @@ -2342,9 +2369,11 @@ static int f2fs_show_options(struct seq_file *seq, struct dentry *root)
>>>> else if (F2FS_OPTION(sbi).fs_mode == FS_MODE_FRAGMENT_BLK)
>>>> seq_puts(seq, "fragment:block");
>>>> seq_printf(seq, ",active_logs=%u", F2FS_OPTION(sbi).active_logs);
>>>> - if (test_opt(sbi, RESERVE_ROOT))
>>>> - seq_printf(seq, ",reserve_root=%u,resuid=%u,resgid=%u",
>>>> + if (test_opt(sbi, RESERVE_ROOT) || test_opt(sbi, RESERVE_NODE))
>>>> + seq_printf(seq, ",reserve_root=%u,reserve_node=%u,resuid=%u,"
>>>> + "resgid=%u",
>>>> F2FS_OPTION(sbi).root_reserved_blocks,
>>>> + F2FS_OPTION(sbi).root_reserved_nodes,
>>>> from_kuid_munged(&init_user_ns,
>>>> F2FS_OPTION(sbi).s_resuid),
>>>> from_kgid_munged(&init_user_ns,
>>
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