[PATCH v2] f2fs: reduce expensive checkpoint trigger frequency

Chao Yu
2021-04-25T01:11:10Z

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);

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