Coda: add spin lock to protect accesses to struct coda_inode_info.
We mostly need it to protect cached user permissions. The c_flags field
is advisory, reading the wrong value is harmless and in the worst case
we hit a slow path where we have to make an extra upcall to the
userspace cache manager when revalidating a dentry or inode.
Signed-off-by: Yoshihisa Abe <yoshiabe@cs.cmu.edu>
Signed-off-by: Jan Harkes <jaharkes@cs.cmu.edu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/coda/dir.c b/fs/coda/dir.c
index ccd98b0..69fbbea 100644
--- a/fs/coda/dir.c
+++ b/fs/coda/dir.c
@@ -18,6 +18,7 @@
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/smp_lock.h>
+#include <linux/spinlock.h>
#include <asm/uaccess.h>
@@ -617,7 +618,9 @@
goto out;
/* clear the flags. */
+ spin_lock(&cii->c_lock);
cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
+ spin_unlock(&cii->c_lock);
bad:
unlock_kernel();
@@ -691,7 +694,10 @@
goto return_bad;
coda_flag_inode_children(inode, C_FLUSH);
+
+ spin_lock(&cii->c_lock);
cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
+ spin_unlock(&cii->c_lock);
}
ok: