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There is no need to use temporary statfs buffer for fsid obliteration

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and prison enforcement.  Do it on the caller buffer directly.

Besides eliminating memory copies, this change also removes large
structure from the kernel stack.

Extracted from:	ino64 work by gleb
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
This commit is contained in:
Konstantin Belousov 2017-01-02 18:59:23 +00:00
parent 3b647ba7aa
commit 7ee34a31fd
1 changed files with 5 additions and 7 deletions
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12
sys/kern/vfs_syscalls.c
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@ -247,7 +247,7 @@ statfs_scale_blocks(struct statfs *sf, long max_size)
static int
kern_do_statfs(struct thread *td, struct mount *mp, struct statfs *buf)
{
struct statfs *sp, sb;
struct statfs *sp;
int error;
if (mp == NULL)
@ -271,13 +271,11 @@ kern_do_statfs(struct thread *td, struct mount *mp, struct statfs *buf)
error = VFS_STATFS(mp, sp);
if (error != 0)
goto out;
if (priv_check(td, PRIV_VFS_GENERATION)) {
bcopy(sp, &sb, sizeof(sb));
sb.f_fsid.val[0] = sb.f_fsid.val[1] = 0;
prison_enforce_statfs(td->td_ucred, mp, &sb);
sp = &sb;
}
*buf = *sp;
if (priv_check(td, PRIV_VFS_GENERATION)) {
buf->f_fsid.val[0] = buf->f_fsid.val[1] = 0;
prison_enforce_statfs(td->td_ucred, mp, buf);
}
out:
vfs_unbusy(mp);
return (error);