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| author | Yoshihisa Abe <yoshiabe@cs.cmu.edu> | 2010-10-25 02:03:44 -0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-10-25 08:02:40 -0700 |
| commit | b5ce1d83a62fc109d8e815b1fc71dcdb0d26bc49 (patch) | |
| tree | ea537c1b6436c36bee3b33d8b4f750124fd7d661 /fs/coda/cache.c | |
| parent | 3a99c6319064af3f2e18eb929f638d555dbf7a62 (diff) | |
| download | linux-3.10-b5ce1d83a62fc109d8e815b1fc71dcdb0d26bc49.tar.gz linux-3.10-b5ce1d83a62fc109d8e815b1fc71dcdb0d26bc49.tar.bz2 linux-3.10-b5ce1d83a62fc109d8e815b1fc71dcdb0d26bc49.zip | |
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>
Diffstat (limited to 'fs/coda/cache.c')
| -rw-r--r-- | fs/coda/cache.c | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/fs/coda/cache.c b/fs/coda/cache.c index a5bf5771a22..9060f08e70c 100644 --- a/fs/coda/cache.c +++ b/fs/coda/cache.c @@ -17,6 +17,7 @@ #include <linux/string.h> #include <linux/list.h> #include <linux/sched.h> +#include <linux/spinlock.h> #include <linux/coda.h> #include <linux/coda_linux.h> @@ -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; } |