Re: [PATCH v2] f2fs: reduce expensive checkpoint trigger frequency

Jaegeuk Kim
2021-04-26T17:09:30Z

On 04/25, 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.
>
> 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().
>
> Reported-by: Yunlei He <heyunlei@hihonor.com>
> Signed-off-by: Chao Yu <yuchao0@huawei.com>
> ---
> v2:
> - fix to set ENC_DIR_INO only for encrypted directory
> 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 b9d5317db0a7..0fe881309a20 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 a595050c56d3..62af29ec0879 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..70615d504f7e 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_encrypted_file(inode) &&
> + f2fs_is_checkpointed_node(sbi, inode->i_ino))
> + f2fs_add_ino_entry(sbi, inode->i_ino, ENC_DIR_INO);

What will happen, if we need to checkpoint xattr_nid on this directory?

>
> 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