From b5ce1d83a62fc109d8e815b1fc71dcdb0d26bc49 Mon Sep 17 00:00:00 2001 From: Yoshihisa Abe Date: Mon, 25 Oct 2010 02:03:44 -0400 Subject: 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 Signed-off-by: Jan Harkes Signed-off-by: Linus Torvalds --- fs/coda/cache.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) (limited to 'fs/coda/cache.c') diff --git a/fs/coda/cache.c b/fs/coda/cache.c index a5bf5771a22a..9060f08e70cf 100644 --- a/fs/coda/cache.c +++ b/fs/coda/cache.c @@ -17,6 +17,7 @@ #include #include #include +#include #include #include @@ -31,19 +32,23 @@ void coda_cache_enter(struct inode *inode, int mask) { struct coda_inode_info *cii = ITOC(inode); + spin_lock(&cii->c_lock); cii->c_cached_epoch = atomic_read(&permission_epoch); if (cii->c_uid != current_fsuid()) { cii->c_uid = current_fsuid(); cii->c_cached_perm = mask; } else cii->c_cached_perm |= mask; + spin_unlock(&cii->c_lock); } /* remove cached acl from an inode */ void coda_cache_clear_inode(struct inode *inode) { struct coda_inode_info *cii = ITOC(inode); + spin_lock(&cii->c_lock); cii->c_cached_epoch = atomic_read(&permission_epoch) - 1; + spin_unlock(&cii->c_lock); } /* remove all acl caches */ @@ -57,13 +62,15 @@ void coda_cache_clear_all(struct super_block *sb) int coda_cache_check(struct inode *inode, int mask) { struct coda_inode_info *cii = ITOC(inode); - int hit; + int hit; - hit = (mask & cii->c_cached_perm) == mask && - cii->c_uid == current_fsuid() && - cii->c_cached_epoch == atomic_read(&permission_epoch); + spin_lock(&cii->c_lock); + hit = (mask & cii->c_cached_perm) == mask && + cii->c_uid == current_fsuid() && + cii->c_cached_epoch == atomic_read(&permission_epoch); + spin_unlock(&cii->c_lock); - return hit; + return hit; } -- cgit v1.2.3