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Cleanup: !A || A && B is equivalent to !A || B 

In zfs_zaccess_dataset_check(), we have the following subexpression:

(!IS_DEVVP(ZTOV(zp)) ||
    (IS_DEVVP(ZTOV(zp)) && (v4_mode & WRITE_MASK_ATTRS)))

When !IS_DEVVP(ZTOV(zp)) is false, IS_DEVVP(ZTOV(zp)) is true under the
law of the excluded middle since we are not doing pseudoboolean alegbra.
Therefore doing:

(IS_DEVVP(ZTOV(zp)) && (v4_mode & WRITE_MASK_ATTRS))

Is unnecessary and we can just do:

(v4_mode & WRITE_MASK_ATTRS)

The Linux 5.16.14 kernel's coccicheck caught this. The semantic
patch that caught it was:

./scripts/coccinelle/misc/excluded_middle.cocci

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Closes #14372
This commit is contained in:
Richard Yao 2023-01-10 16:34:29 -05:00 committed by Brian Behlendorf
parent 9c8fabffa2
commit e6328fda2e
2 changed files with 2 additions and 4 deletions
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3
module/os/freebsd/zfs/zfs_acl.c
View File

@ -2041,8 +2041,7 @@ zfs_zaccess_dataset_check(znode_t *zp, uint32_t v4_mode)
{
if ((v4_mode & WRITE_MASK) &&
(zp->z_zfsvfs->z_vfs->vfs_flag & VFS_RDONLY) &&
(!IS_DEVVP(ZTOV(zp)) ||
(IS_DEVVP(ZTOV(zp)) && (v4_mode & WRITE_MASK_ATTRS)))) {
(!IS_DEVVP(ZTOV(zp)) || (v4_mode & WRITE_MASK_ATTRS))) {
return (SET_ERROR(EROFS));
}

3
module/os/linux/zfs/zfs_acl.c
View File

@ -2233,8 +2233,7 @@ static int
zfs_zaccess_dataset_check(znode_t *zp, uint32_t v4_mode)
{
if ((v4_mode & WRITE_MASK) && (zfs_is_readonly(ZTOZSB(zp))) &&
(!Z_ISDEV(ZTOI(zp)->i_mode) ||
(Z_ISDEV(ZTOI(zp)->i_mode) && (v4_mode & WRITE_MASK_ATTRS)))) {
(!Z_ISDEV(ZTOI(zp)->i_mode) || (v4_mode & WRITE_MASK_ATTRS))) {
return (SET_ERROR(EROFS));
}