From 763e2ea32f408f1b620a527274fa0e8d66ef7c75 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Sun, 19 Jul 2009 08:44:27 -0500 Subject: 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 --- fs/namespace.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) (limited to 'fs') diff --git a/fs/namespace.c b/fs/namespace.c index cfc6d4448aa5..63fd6d78be27 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; } -- cgit v1.2.3