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authorLinus Torvalds <torvalds@linux-foundation.org>2011-08-04 16:44:40 -1000
committerLinus Torvalds <torvalds@linux-foundation.org>2011-08-04 16:44:40 -1000
commit24f0eed2668b059e847ff145848ddacb75419acc (patch)
tree010c89c06e191b068f8a078b10bfaf1d3699c834
parent8b6b4628126fd73d0a53b499a26133c15b73c1e6 (diff)
parent3567866bf26190d1e734c975c907eb06e923ba23 (diff)
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: RCUify freeing acls, let check_acl() go ahead in RCU mode if acl is cached get rid of boilerplate switches in posix_acl.h fix block device fallout from ->fsync() changes
-rw-r--r--fs/block_dev.c4
-rw-r--r--fs/namei.c17
-rw-r--r--include/linux/posix_acl.h74
3 files changed, 36 insertions, 59 deletions
diff --git a/fs/block_dev.c b/fs/block_dev.c
index f28680553288..ff77262e887c 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -387,6 +387,10 @@ int blkdev_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
struct inode *bd_inode = filp->f_mapping->host;
struct block_device *bdev = I_BDEV(bd_inode);
int error;
+
+ error = filemap_write_and_wait_range(filp->f_mapping, start, end);
+ if (error)
+ return error;
/*
* There is no need to serialise calls to blkdev_issue_flush with
diff --git a/fs/namei.c b/fs/namei.c
index 445fd5da11fa..3d607bd80e09 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -179,19 +179,14 @@ static int check_acl(struct inode *inode, int mask)
#ifdef CONFIG_FS_POSIX_ACL
struct posix_acl *acl;
- /*
- * Under RCU walk, we cannot even do a "get_cached_acl()",
- * because that involves locking and getting a refcount on
- * a cached ACL.
- *
- * So the only case we handle during RCU walking is the
- * case of a cached "no ACL at all", which needs no locks
- * or refcounts.
- */
if (mask & MAY_NOT_BLOCK) {
- if (negative_cached_acl(inode, ACL_TYPE_ACCESS))
+ acl = get_cached_acl_rcu(inode, ACL_TYPE_ACCESS);
+ if (!acl)
return -EAGAIN;
- return -ECHILD;
+ /* no ->get_acl() calls in RCU mode... */
+ if (acl == ACL_NOT_CACHED)
+ return -ECHILD;
+ return posix_acl_permission(inode, acl, mask);
}
acl = get_cached_acl(inode, ACL_TYPE_ACCESS);
diff --git a/include/linux/posix_acl.h b/include/linux/posix_acl.h
index 951bba82d50d..b7681102a4b9 100644
--- a/include/linux/posix_acl.h
+++ b/include/linux/posix_acl.h
@@ -9,6 +9,7 @@
#define __LINUX_POSIX_ACL_H
#include <linux/slab.h>
+#include <linux/rcupdate.h>
#define ACL_UNDEFINED_ID (-1)
@@ -38,7 +39,10 @@ struct posix_acl_entry {
};
struct posix_acl {
- atomic_t a_refcount;
+ union {
+ atomic_t a_refcount;
+ struct rcu_head a_rcu;
+ };
unsigned int a_count;
struct posix_acl_entry a_entries[0];
};
@@ -65,7 +69,7 @@ static inline void
posix_acl_release(struct posix_acl *acl)
{
if (acl && atomic_dec_and_test(&acl->a_refcount))
- kfree(acl);
+ kfree_rcu(acl, a_rcu);
}
@@ -84,20 +88,22 @@ extern struct posix_acl *get_posix_acl(struct inode *, int);
extern int set_posix_acl(struct inode *, int, struct posix_acl *);
#ifdef CONFIG_FS_POSIX_ACL
-static inline struct posix_acl *get_cached_acl(struct inode *inode, int type)
+static inline struct posix_acl **acl_by_type(struct inode *inode, int type)
{
- struct posix_acl **p, *acl;
switch (type) {
case ACL_TYPE_ACCESS:
- p = &inode->i_acl;
- break;
+ return &inode->i_acl;
case ACL_TYPE_DEFAULT:
- p = &inode->i_default_acl;
- break;
+ return &inode->i_default_acl;
default:
- return ERR_PTR(-EINVAL);
+ BUG();
}
- acl = ACCESS_ONCE(*p);
+}
+
+static inline struct posix_acl *get_cached_acl(struct inode *inode, int type)
+{
+ struct posix_acl **p = acl_by_type(inode, type);
+ struct posix_acl *acl = ACCESS_ONCE(*p);
if (acl) {
spin_lock(&inode->i_lock);
acl = *p;
@@ -108,41 +114,20 @@ static inline struct posix_acl *get_cached_acl(struct inode *inode, int type)
return acl;
}
-static inline int negative_cached_acl(struct inode *inode, int type)
+static inline struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type)
{
- struct posix_acl **p, *acl;
- switch (type) {
- case ACL_TYPE_ACCESS:
- p = &inode->i_acl;
- break;
- case ACL_TYPE_DEFAULT:
- p = &inode->i_default_acl;
- break;
- default:
- BUG();
- }
- acl = ACCESS_ONCE(*p);
- if (acl)
- return 0;
- return 1;
+ return rcu_dereference(*acl_by_type(inode, type));
}
static inline void set_cached_acl(struct inode *inode,
int type,
struct posix_acl *acl)
{
- struct posix_acl *old = NULL;
+ struct posix_acl **p = acl_by_type(inode, type);
+ struct posix_acl *old;
spin_lock(&inode->i_lock);
- switch (type) {
- case ACL_TYPE_ACCESS:
- old = inode->i_acl;
- inode->i_acl = posix_acl_dup(acl);
- break;
- case ACL_TYPE_DEFAULT:
- old = inode->i_default_acl;
- inode->i_default_acl = posix_acl_dup(acl);
- break;
- }
+ old = *p;
+ rcu_assign_pointer(*p, posix_acl_dup(acl));
spin_unlock(&inode->i_lock);
if (old != ACL_NOT_CACHED)
posix_acl_release(old);
@@ -150,18 +135,11 @@ static inline void set_cached_acl(struct inode *inode,
static inline void forget_cached_acl(struct inode *inode, int type)
{
- struct posix_acl *old = NULL;
+ struct posix_acl **p = acl_by_type(inode, type);
+ struct posix_acl *old;
spin_lock(&inode->i_lock);
- switch (type) {
- case ACL_TYPE_ACCESS:
- old = inode->i_acl;
- inode->i_acl = ACL_NOT_CACHED;
- break;
- case ACL_TYPE_DEFAULT:
- old = inode->i_default_acl;
- inode->i_default_acl = ACL_NOT_CACHED;
- break;
- }
+ old = *p;
+ *p = ACL_NOT_CACHED;
spin_unlock(&inode->i_lock);
if (old != ACL_NOT_CACHED)
posix_acl_release(old);