fs: provide rcu-walk aware permission i_ops

Signed-off-by: Nick Piggin <npiggin@kernel.dk>

6 files changed, 20 insertions, 13 deletions

diff --git a/fs/gfs2/acl.c b/fs/gfs2/acl.c
index 48171f4c943d..7118f1a780a9 100644
--- a/fs/gfs2/acl.c
+++ b/fs/gfs2/acl.c
@@ -75,11 +75,14 @@ static struct posix_acl *gfs2_acl_get(struct gfs2_inode *ip, int type)
  * Returns: errno
  */
 
-int gfs2_check_acl(struct inode *inode, int mask)
+int gfs2_check_acl(struct inode *inode, int mask, unsigned int flags)
 {
         struct posix_acl *acl;
         int error;
 
+        if (flags & IPERM_FLAG_RCU)
+                return -ECHILD;
+
         acl = gfs2_acl_get(GFS2_I(inode), ACL_TYPE_ACCESS);
         if (IS_ERR(acl))
                 return PTR_ERR(acl);
diff --git a/fs/gfs2/acl.h b/fs/gfs2/acl.h
index b522b0cb39ea..a93907c8159b 100644
--- a/fs/gfs2/acl.h
+++ b/fs/gfs2/acl.h
@@ -16,7 +16,7 @@
 #define GFS2_POSIX_ACL_DEFAULT          "posix_acl_default"
 #define GFS2_ACL_MAX_ENTRIES            25
 
-extern int gfs2_check_acl(struct inode *inode, int mask);
+extern int gfs2_check_acl(struct inode *inode, int mask, unsigned int);
 extern int gfs2_acl_create(struct gfs2_inode *dip, struct inode *inode);
 extern int gfs2_acl_chmod(struct gfs2_inode *ip, struct iattr *attr);
 extern const struct xattr_handler gfs2_xattr_system_handler;
diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index aa996471ec5c..fca6689e12e6 100644
--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -241,7 +241,7 @@ static int do_gfs2_set_flags(struct file *filp, u32 reqflags, u32 mask)
             !capable(CAP_LINUX_IMMUTABLE))
                 goto out;
         if (!IS_IMMUTABLE(inode)) {
-                error = gfs2_permission(inode, MAY_WRITE);
+                error = gfs2_permission(inode, MAY_WRITE, 0);
                 if (error)
                         goto out;
         }
diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index e1213f7f9217..6163be9686be 100644
--- a/fs/gfs2/inode.c
+++ b/fs/gfs2/inode.c
@@ -509,7 +509,7 @@ struct inode *gfs2_lookupi(struct inode *dir, const struct qstr *name,
         }
 
         if (!is_root) {
-                error = gfs2_permission(dir, MAY_EXEC);
+                error = gfs2_permission(dir, MAY_EXEC, 0);
                 if (error)
                         goto out;
         }
@@ -539,7 +539,7 @@ static int create_ok(struct gfs2_inode *dip, const struct qstr *name,
 {
         int error;
 
-        error = gfs2_permission(&dip->i_inode, MAY_WRITE | MAY_EXEC);
+        error = gfs2_permission(&dip->i_inode, MAY_WRITE | MAY_EXEC, 0);
         if (error)
                 return error;
 
diff --git a/fs/gfs2/inode.h b/fs/gfs2/inode.h
index d8499fadcc53..732a183efdb3 100644
--- a/fs/gfs2/inode.h
+++ b/fs/gfs2/inode.h
@@ -113,7 +113,7 @@ extern struct inode *gfs2_lookupi(struct inode *dir, const struct qstr *name,
 extern struct inode *gfs2_createi(struct gfs2_holder *ghs,
                                   const struct qstr *name,
                                   unsigned int mode, dev_t dev);
-extern int gfs2_permission(struct inode *inode, int mask);
+extern int gfs2_permission(struct inode *inode, int mask, unsigned int flags);
 extern int gfs2_setattr_simple(struct gfs2_inode *ip, struct iattr *attr);
 extern struct inode *gfs2_lookup_simple(struct inode *dip, const char *name);
 extern void gfs2_dinode_out(const struct gfs2_inode *ip, void *buf);
diff --git a/fs/gfs2/ops_inode.c b/fs/gfs2/ops_inode.c
index f28f89796f4d..5c63a06fcd7c 100644
--- a/fs/gfs2/ops_inode.c
+++ b/fs/gfs2/ops_inode.c
@@ -166,7 +166,7 @@ static int gfs2_link(struct dentry *old_dentry, struct inode *dir,
         if (error)
                 goto out_child;
 
-        error = gfs2_permission(dir, MAY_WRITE | MAY_EXEC);
+        error = gfs2_permission(dir, MAY_WRITE | MAY_EXEC, 0);
         if (error)
                 goto out_gunlock;
 
@@ -289,7 +289,7 @@ static int gfs2_unlink_ok(struct gfs2_inode *dip, const struct qstr *name,
         if (IS_APPEND(&dip->i_inode))
                 return -EPERM;
 
-        error = gfs2_permission(&dip->i_inode, MAY_WRITE | MAY_EXEC);
+        error = gfs2_permission(&dip->i_inode, MAY_WRITE | MAY_EXEC, 0);
         if (error)
                 return error;
 
@@ -822,7 +822,7 @@ static int gfs2_rename(struct inode *odir, struct dentry *odentry,
                         }
                 }
         } else {
-                error = gfs2_permission(ndir, MAY_WRITE | MAY_EXEC);
+                error = gfs2_permission(ndir, MAY_WRITE | MAY_EXEC, 0);
                 if (error)
                         goto out_gunlock;
 
@@ -857,7 +857,7 @@ static int gfs2_rename(struct inode *odir, struct dentry *odentry,
         /* Check out the dir to be renamed */
 
         if (dir_rename) {
-                error = gfs2_permission(odentry->d_inode, MAY_WRITE);
+                error = gfs2_permission(odentry->d_inode, MAY_WRITE, 0);
                 if (error)
                         goto out_gunlock;
         }
@@ -1041,13 +1041,17 @@ static void gfs2_put_link(struct dentry *dentry, struct nameidata *nd, void *p)
  * Returns: errno
  */
 
-int gfs2_permission(struct inode *inode, int mask)
+int gfs2_permission(struct inode *inode, int mask, unsigned int flags)
 {
-        struct gfs2_inode *ip = GFS2_I(inode);
+        struct gfs2_inode *ip;
         struct gfs2_holder i_gh;
         int error;
         int unlock = 0;
 
+        if (flags & IPERM_FLAG_RCU)
+                return -ECHILD;
+
+        ip = GFS2_I(inode);
         if (gfs2_glock_is_locked_by_me(ip->i_gl) == NULL) {
                 error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
                 if (error)
@@ -1058,7 +1062,7 @@ int gfs2_permission(struct inode *inode, int mask)
         if ((mask & MAY_WRITE) && IS_IMMUTABLE(inode))
                 error = -EACCES;
         else
-                error = generic_permission(inode, mask, gfs2_check_acl);
+                error = generic_permission(inode, mask, flags, gfs2_check_acl);
         if (unlock)
                 gfs2_glock_dq_uninit(&i_gh);