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SubjectRe: [RFC PATCH] f2fs: reduce expensive checkpoint trigger frequency
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On 2021/4/22 12:06, Jaegeuk Kim wrote:
> On 04/16, Chao Yu wrote:
>> We may trigger high frequent checkpoint for below case:
>> 1. mkdir /mnt/dir1; set dir1 encrypted
>> 2. touch /mnt/file1; fsync /mnt/file1
>> 3. mkdir /mnt/dir2; set dir2 encrypted
>> 4. touch /mnt/file2; fsync /mnt/file2
>> ...
>>
>> Although, newly created dir and file are not related, due to
>> commit bbf156f7afa7 ("f2fs: fix lost xattrs of directories"), we will
>> trigger checkpoint whenever fsync() comes after a new encrypted dir
>> created.
>
> It'll happen once? How much impact will we hit due to this?

Yunlei reports me this issue, the problems here in Honer device's specified
environment, most fsync() on regular file triggers a checkpoint() when mkdir()
happened concurrently, result in causing the performance issue.

Yunlei could explain more about details of this issue. @Yunlei

>
>>
>> In order to avoid such condition, let's record an entry including
>> directory's ino into global cache when we initialize encryption policy
>> in a checkpointed directory, and then only trigger checkpoint() when
>> target file's parent has non-persisted encryption policy, for the case
>> its parent is not checkpointed, need_do_checkpoint() has cover that
>> by verifying it with f2fs_is_checkpointed_node().
>>
>> Signed-off-by: Chao Yu <yuchao0@huawei.com>
>> ---
>> fs/f2fs/f2fs.h | 2 ++
>> fs/f2fs/file.c | 3 +++
>> fs/f2fs/xattr.c | 6 ++++--
>> include/trace/events/f2fs.h | 3 ++-
>> 4 files changed, 11 insertions(+), 3 deletions(-)
>>
>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>> index 87d734f5589d..34487e527d12 100644
>> --- a/fs/f2fs/f2fs.h
>> +++ b/fs/f2fs/f2fs.h
>> @@ -246,6 +246,7 @@ enum {
>> APPEND_INO, /* for append ino list */
>> UPDATE_INO, /* for update ino list */
>> TRANS_DIR_INO, /* for trasactions dir ino list */
>> + ENC_DIR_INO, /* for encrypted dir ino list */
>> FLUSH_INO, /* for multiple device flushing */
>> MAX_INO_ENTRY, /* max. list */
>> };
>> @@ -1090,6 +1091,7 @@ enum cp_reason_type {
>> CP_FASTBOOT_MODE,
>> CP_SPEC_LOG_NUM,
>> CP_RECOVER_DIR,
>> + CP_ENC_DIR,
>> };
>>
>> enum iostat_type {
>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
>> index 6284b2f4a60b..a6c38d8b1ec3 100644
>> --- a/fs/f2fs/file.c
>> +++ b/fs/f2fs/file.c
>> @@ -218,6 +218,9 @@ static inline enum cp_reason_type need_do_checkpoint(struct inode *inode)
>> f2fs_exist_written_data(sbi, F2FS_I(inode)->i_pino,
>> TRANS_DIR_INO))
>> cp_reason = CP_RECOVER_DIR;
>> + else if (f2fs_exist_written_data(sbi, F2FS_I(inode)->i_pino,
>> + ENC_DIR_INO))
>> + cp_reason = CP_ENC_DIR;
>>
>> return cp_reason;
>> }
>> diff --git a/fs/f2fs/xattr.c b/fs/f2fs/xattr.c
>> index c8f34decbf8e..38796d488d15 100644
>> --- a/fs/f2fs/xattr.c
>> +++ b/fs/f2fs/xattr.c
>> @@ -630,6 +630,7 @@ static int __f2fs_setxattr(struct inode *inode, int index,
>> const char *name, const void *value, size_t size,
>> struct page *ipage, int flags)
>> {
>> + struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
>> struct f2fs_xattr_entry *here, *last;
>> void *base_addr, *last_base_addr;
>> int found, newsize;
>> @@ -745,8 +746,9 @@ static int __f2fs_setxattr(struct inode *inode, int index,
>> !strcmp(name, F2FS_XATTR_NAME_ENCRYPTION_CONTEXT))
>> f2fs_set_encrypted_inode(inode);
>> f2fs_mark_inode_dirty_sync(inode, true);
>> - if (!error && S_ISDIR(inode->i_mode))
>> - set_sbi_flag(F2FS_I_SB(inode), SBI_NEED_CP);
>> + if (!error && S_ISDIR(inode->i_mode) &&
>> + f2fs_is_checkpointed_node(sbi, inode->i_ino))
>> + f2fs_add_ino_entry(sbi, inode->i_ino, ENC_DIR_INO);
>
> Is it right to say ENC_DIR_INO in this case?

Sorry, I didn't get it.

Thanks,

>
>>
>> same:
>> if (is_inode_flag_set(inode, FI_ACL_MODE)) {
>> diff --git a/include/trace/events/f2fs.h b/include/trace/events/f2fs.h
>> index 56b113e3cd6a..ca0cf12226e9 100644
>> --- a/include/trace/events/f2fs.h
>> +++ b/include/trace/events/f2fs.h
>> @@ -145,7 +145,8 @@ TRACE_DEFINE_ENUM(CP_RESIZE);
>> { CP_NODE_NEED_CP, "node needs cp" }, \
>> { CP_FASTBOOT_MODE, "fastboot mode" }, \
>> { CP_SPEC_LOG_NUM, "log type is 2" }, \
>> - { CP_RECOVER_DIR, "dir needs recovery" })
>> + { CP_RECOVER_DIR, "dir needs recovery" }, \
>> + { CP_ENC_DIR, "persist encryption policy" })
>>
>> #define show_shutdown_mode(type) \
>> __print_symbolic(type, \
>> --
>> 2.29.2
> .
>

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