diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2009-07-19 08:44:27 -0500 |
|---|---|---|
| committer | Clark Williams <williams@redhat.com> | 2011-11-14 11:02:03 -0600 |
| commit | 6fe36e5a43a46eea22b1ba469c6919f06bb4ed0f (patch) | |
| tree | 94dfd52529e0822e3da26b16f4441438c53b6520 | |
| parent | 16195d2af126e6199affe16752c9999bf17d387b (diff) | |
fs: namespace preemption fix
On RT we cannot loop with preemption disabled here as
mnt_make_readonly() might have been preempted. We can safely enable
preemption while waiting for MNT_WRITE_HOLD to be cleared. Safe on !RT
as well.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| -rw-r--r-- | fs/namespace.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/fs/namespace.c b/fs/namespace.c index e5e1c7d1839b..7253dcc4cb49 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -341,8 +341,14 @@ int mnt_want_write(struct vfsmount *mnt) * incremented count after it has set MNT_WRITE_HOLD. */ smp_mb(); - while (mnt->mnt_flags & MNT_WRITE_HOLD) + /* + * No need to keep preemption disabled accross the spin loop. + */ + while (mnt->mnt_flags & MNT_WRITE_HOLD) { + preempt_enable(); cpu_relax(); + preempt_disable(); + } /* * After the slowpath clears MNT_WRITE_HOLD, mnt_is_readonly will * be set to match its requirements. So we must not load that until @@ -352,9 +358,7 @@ int mnt_want_write(struct vfsmount *mnt) if (__mnt_is_readonly(mnt)) { mnt_dec_writers(mnt); ret = -EROFS; - goto out; } -out: preempt_enable(); return ret; } |