[PATCH 4/4] fs/ntfs3: Optimize locking in ntfs_save_wsl_perm

From: Konstantin Komarov
Date: Tue Oct 26 2021 - 12:42:23 EST


Right now in ntfs_save_wsl_perm we lock/unlock 4 times.
This commit fixes this situation.
We add "locked" argument to ntfs_set_ea.

Suggested-by: Kari Argillander <kari.argillander@xxxxxxxxx>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@xxxxxxxxxxxxxxxxxxxx>
---
fs/ntfs3/xattr.c | 24 ++++++++++++++----------
1 file changed, 14 insertions(+), 10 deletions(-)

diff --git a/fs/ntfs3/xattr.c b/fs/ntfs3/xattr.c
index 157b70aecb4f..6d8b1cd7681d 100644
--- a/fs/ntfs3/xattr.c
+++ b/fs/ntfs3/xattr.c
@@ -259,7 +259,7 @@ static int ntfs_get_ea(struct inode *inode, const char *name, size_t name_len,

static noinline int ntfs_set_ea(struct inode *inode, const char *name,
size_t name_len, const void *value,
- size_t val_size, int flags)
+ size_t val_size, int flags, bool locked)
{
struct ntfs_inode *ni = ntfs_i(inode);
struct ntfs_sb_info *sbi = ni->mi.sbi;
@@ -278,7 +278,8 @@ static noinline int ntfs_set_ea(struct inode *inode, const char *name,
u64 new_sz;
void *p;

- ni_lock(ni);
+ if (!locked)
+ ni_lock(ni);

run_init(&ea_run);

@@ -467,7 +468,8 @@ static noinline int ntfs_set_ea(struct inode *inode, const char *name,
mark_inode_dirty(&ni->vfs_inode);

out:
- ni_unlock(ni);
+ if (!locked)
+ ni_unlock(ni);

run_close(&ea_run);
kfree(ea_all);
@@ -595,7 +597,7 @@ static noinline int ntfs_set_acl_ex(struct user_namespace *mnt_userns,
flags = 0;
}

- err = ntfs_set_ea(inode, name, name_len, value, size, flags);
+ err = ntfs_set_ea(inode, name, name_len, value, size, flags, 0);
if (err == -ENODATA && !size)
err = 0; /* Removing non existed xattr. */
if (!err)
@@ -989,7 +991,7 @@ static noinline int ntfs_setxattr(const struct xattr_handler *handler,
}
#endif
/* Deal with NTFS extended attribute. */
- err = ntfs_set_ea(inode, name, name_len, value, size, flags);
+ err = ntfs_set_ea(inode, name, name_len, value, size, flags, 0);

out:
inode->i_ctime = current_time(inode);
@@ -1007,35 +1009,37 @@ int ntfs_save_wsl_perm(struct inode *inode)
{
int err;
__le32 value;
+ struct ntfs_inode *ni = ntfs_i(inode);

- /* TODO: refactor this, so we don't lock 4 times in ntfs_set_ea */
+ ni_lock(ni);
value = cpu_to_le32(i_uid_read(inode));
err = ntfs_set_ea(inode, "$LXUID", sizeof("$LXUID") - 1, &value,
- sizeof(value), 0);
+ sizeof(value), 0, true); /* true == already locked. */
if (err)
goto out;

value = cpu_to_le32(i_gid_read(inode));
err = ntfs_set_ea(inode, "$LXGID", sizeof("$LXGID") - 1, &value,
- sizeof(value), 0);
+ sizeof(value), 0, true);
if (err)
goto out;

value = cpu_to_le32(inode->i_mode);
err = ntfs_set_ea(inode, "$LXMOD", sizeof("$LXMOD") - 1, &value,
- sizeof(value), 0);
+ sizeof(value), 0, true);
if (err)
goto out;

if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
value = cpu_to_le32(inode->i_rdev);
err = ntfs_set_ea(inode, "$LXDEV", sizeof("$LXDEV") - 1, &value,
- sizeof(value), 0);
+ sizeof(value), 0, true);
if (err)
goto out;
}

out:
+ ni_unlock(ni);
/* In case of error should we delete all WSL xattr? */
return err;
}
--
2.33.0