[Cluster-devel] [PATCH 03/30] GFS2: Fix up system xattrs

[Steven Whitehouse <swhiteho@redhat.com>]

This code has been shamelessly stolen from XFS at the suggestion
of Christoph Hellwig. I've not added support for cached ACLs so
far... watch for that in a later patch, although this is designed
in such a way that they should be easy to add.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
---
 fs/gfs2/acl.c   |  170 +++++++++++++++++++++++++++++++++++++------------------
 fs/gfs2/acl.h   |   24 ++------
 fs/gfs2/xattr.c |   18 ------
 3 files changed, 120 insertions(+), 92 deletions(-)

diff --git a/fs/gfs2/acl.c b/fs/gfs2/acl.c
index 3fc4e3a..2168da1 100644
--- a/fs/gfs2/acl.c
+++ b/fs/gfs2/acl.c
@@ -12,6 +12,7 @@
 #include <linux/spinlock.h>
 #include <linux/completion.h>
 #include <linux/buffer_head.h>
+#include <linux/xattr.h>
 #include <linux/posix_acl.h>
 #include <linux/posix_acl_xattr.h>
 #include <linux/gfs2_ondisk.h>
@@ -26,61 +27,6 @@
 #include "trans.h"
 #include "util.h"
 
-#define ACL_ACCESS 1
-#define ACL_DEFAULT 0
-
-int gfs2_acl_validate_set(struct gfs2_inode *ip, int access,
-			  struct gfs2_ea_request *er, int *remove, mode_t *mode)
-{
-	struct posix_acl *acl;
-	int error;
-
-	error = gfs2_acl_validate_remove(ip, access);
-	if (error)
-		return error;
-
-	if (!er->er_data)
-		return -EINVAL;
-
-	acl = posix_acl_from_xattr(er->er_data, er->er_data_len);
-	if (IS_ERR(acl))
-		return PTR_ERR(acl);
-	if (!acl) {
-		*remove = 1;
-		return 0;
-	}
-
-	error = posix_acl_valid(acl);
-	if (error)
-		goto out;
-
-	if (access) {
-		error = posix_acl_equiv_mode(acl, mode);
-		if (!error)
-			*remove = 1;
-		else if (error > 0)
-			error = 0;
-	}
-
-out:
-	posix_acl_release(acl);
-	return error;
-}
-
-int gfs2_acl_validate_remove(struct gfs2_inode *ip, int access)
-{
-	if (!GFS2_SB(&ip->i_inode)->sd_args.ar_posix_acl)
-		return -EOPNOTSUPP;
-	if (!is_owner_or_cap(&ip->i_inode))
-		return -EPERM;
-	if (S_ISLNK(ip->i_inode.i_mode))
-		return -EOPNOTSUPP;
-	if (!access && !S_ISDIR(ip->i_inode.i_mode))
-		return -EACCES;
-
-	return 0;
-}
-
 static int acl_get(struct gfs2_inode *ip, const char *name,
 		   struct posix_acl **acl, struct gfs2_ea_location *el,
 		   char **datap, unsigned int *lenp)
@@ -277,3 +223,117 @@ out_brelse:
 	return error;
 }
 
+static int gfs2_acl_type(const char *name)
+{
+	if (strcmp(name, GFS2_POSIX_ACL_ACCESS) == 0)
+		return ACL_TYPE_ACCESS;
+	if (strcmp(name, GFS2_POSIX_ACL_DEFAULT) == 0)
+		return ACL_TYPE_DEFAULT;
+	return -EINVAL;
+}
+
+static int gfs2_xattr_system_get(struct inode *inode, const char *name,
+				 void *buffer, size_t size)
+{
+	int type;
+
+	type = gfs2_acl_type(name);
+	if (type < 0)
+		return type;
+
+	return gfs2_xattr_get(inode, GFS2_EATYPE_SYS, name, buffer, size);
+}
+
+static int gfs2_set_mode(struct inode *inode, mode_t mode)
+{
+	int error = 0;
+
+	if (mode != inode->i_mode) {
+		struct iattr iattr;
+
+		iattr.ia_valid = ATTR_MODE;
+		iattr.ia_mode = mode;
+
+		error = gfs2_setattr_simple(GFS2_I(inode), &iattr);
+	}
+
+	return error;
+}
+
+static int gfs2_xattr_system_set(struct inode *inode, const char *name,
+				 const void *value, size_t size, int flags)
+{
+	struct gfs2_sbd *sdp = GFS2_SB(inode);
+	struct posix_acl *acl = NULL;
+	int error = 0, type;
+
+	if (!sdp->sd_args.ar_posix_acl)
+		return -EOPNOTSUPP;
+
+	type = gfs2_acl_type(name);
+	if (type < 0)
+		return type;
+	if (flags & XATTR_CREATE)
+		return -EINVAL;
+	if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
+		return value ? -EACCES : 0;
+	if ((current_fsuid() != inode->i_uid) && !capable(CAP_FOWNER))
+		return -EPERM;
+	if (S_ISLNK(inode->i_mode))
+		return -EOPNOTSUPP;
+
+	if (!value)
+		goto set_acl;
+
+	acl = posix_acl_from_xattr(value, size);
+	if (!acl) {
+		/*
+		 * acl_set_file(3) may request that we set default ACLs with
+		 * zero length -- defend (gracefully) against that here.
+		 */
+		goto out;
+	}
+	if (IS_ERR(acl)) {
+		error = PTR_ERR(acl);
+		goto out;
+	}
+
+	error = posix_acl_valid(acl);
+	if (error)
+		goto out_release;
+
+	error = -EINVAL;
+	if (acl->a_count > GFS2_ACL_MAX_ENTRIES)
+		goto out_release;
+
+	if (type == ACL_TYPE_ACCESS) {
+		mode_t mode = inode->i_mode;
+		error = posix_acl_equiv_mode(acl, &mode);
+
+		if (error <= 0) {
+			posix_acl_release(acl);
+			acl = NULL;
+
+			if (error < 0)
+				return error;
+		}
+
+		error = gfs2_set_mode(inode, mode);
+		if (error)
+			goto out_release;
+	}
+
+set_acl:
+	error = gfs2_xattr_set(inode, GFS2_EATYPE_SYS, name, value, size, 0);
+out_release:
+	posix_acl_release(acl);
+out:
+	return error;
+}
+
+struct xattr_handler gfs2_xattr_system_handler = {
+	.prefix = XATTR_SYSTEM_PREFIX,
+	.get    = gfs2_xattr_system_get,
+	.set    = gfs2_xattr_system_set,
+};
+
diff --git a/fs/gfs2/acl.h b/fs/gfs2/acl.h
index 6751930..cc95439 100644
--- a/fs/gfs2/acl.h
+++ b/fs/gfs2/acl.h
@@ -13,26 +13,12 @@
 #include "incore.h"
 
 #define GFS2_POSIX_ACL_ACCESS		"posix_acl_access"
-#define GFS2_POSIX_ACL_ACCESS_LEN	16
 #define GFS2_POSIX_ACL_DEFAULT		"posix_acl_default"
-#define GFS2_POSIX_ACL_DEFAULT_LEN	17
+#define GFS2_ACL_MAX_ENTRIES		25
 
-#define GFS2_ACL_IS_ACCESS(name, len) \
-         ((len) == GFS2_POSIX_ACL_ACCESS_LEN && \
-         !memcmp(GFS2_POSIX_ACL_ACCESS, (name), (len)))
-
-#define GFS2_ACL_IS_DEFAULT(name, len) \
-         ((len) == GFS2_POSIX_ACL_DEFAULT_LEN && \
-         !memcmp(GFS2_POSIX_ACL_DEFAULT, (name), (len)))
-
-struct gfs2_ea_request;
-
-int gfs2_acl_validate_set(struct gfs2_inode *ip, int access,
-			  struct gfs2_ea_request *er,
-			  int *remove, mode_t *mode);
-int gfs2_acl_validate_remove(struct gfs2_inode *ip, int access);
-int gfs2_check_acl(struct inode *inode, int mask);
-int gfs2_acl_create(struct gfs2_inode *dip, struct gfs2_inode *ip);
-int gfs2_acl_chmod(struct gfs2_inode *ip, struct iattr *attr);
+extern int gfs2_check_acl(struct inode *inode, int mask);
+extern int gfs2_acl_create(struct gfs2_inode *dip, struct gfs2_inode *ip);
+extern int gfs2_acl_chmod(struct gfs2_inode *ip, struct iattr *attr);
+extern struct xattr_handler gfs2_xattr_system_handler;
 
 #endif /* __ACL_DOT_H__ */
diff --git a/fs/gfs2/xattr.c b/fs/gfs2/xattr.c
index 8a0f8ef..6b80354 100644
--- a/fs/gfs2/xattr.c
+++ b/fs/gfs2/xattr.c
@@ -1507,18 +1507,6 @@ static int gfs2_xattr_user_set(struct inode *inode, const char *name,
 	return gfs2_xattr_set(inode, GFS2_EATYPE_USR, name, value, size, flags);
 }
 
-static int gfs2_xattr_system_get(struct inode *inode, const char *name,
-				 void *buffer, size_t size)
-{
-	return gfs2_xattr_get(inode, GFS2_EATYPE_SYS, name, buffer, size);
-}
-
-static int gfs2_xattr_system_set(struct inode *inode, const char *name,
-				 const void *value, size_t size, int flags)
-{
-	return gfs2_xattr_set(inode, GFS2_EATYPE_SYS, name, value, size, flags);
-}
-
 static int gfs2_xattr_security_get(struct inode *inode, const char *name,
 				   void *buffer, size_t size)
 {
@@ -1543,12 +1531,6 @@ static struct xattr_handler gfs2_xattr_security_handler = {
 	.set    = gfs2_xattr_security_set,
 };
 
-static struct xattr_handler gfs2_xattr_system_handler = {
-	.prefix = XATTR_SYSTEM_PREFIX,
-	.get    = gfs2_xattr_system_get,
-	.set    = gfs2_xattr_system_set,
-};
-
 struct xattr_handler *gfs2_xattr_handlers[] = {
 	&gfs2_xattr_user_handler,
 	&gfs2_xattr_security_handler,
-- 
1.6.2.5