cifs: Switch to generic xattr handlers

Use xattr handlers for resolving attribute names.  The amount of setup
code required on cifs is nontrivial, so use the same get and set
functions for all handlers, with switch statements for the different
types of attributes in them.

The set_EA handler can handle NULL values, so we don't need a separate
removexattr function anymore.  Remove the cifs_dbg statements related to
xattr name resolution; they don't add much.  Don't build xattr.o when
CONFIG_CIFS_XATTR is not defined.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/cifs/Makefile

@@ -5,9 +5,10 @@ obj-$(CONFIG_CIFS) += cifs.o
 
 cifs-y := cifsfs.o cifssmb.o cifs_debug.o connect.o dir.o file.o inode.o \
 	  link.o misc.o netmisc.o smbencrypt.o transport.o asn1.o \
-	  cifs_unicode.o nterr.o xattr.o cifsencrypt.o \
+	  cifs_unicode.o nterr.o cifsencrypt.o \
 	  readdir.o ioctl.o sess.o export.o smb1ops.o winucase.o
 
+cifs-$(CONFIG_CIFS_XATTR) += xattr.o
 cifs-$(CONFIG_CIFS_ACL) += cifsacl.o
 
 cifs-$(CONFIG_CIFS_UPCALL) += cifs_spnego.o

fs/cifs/cifsfs.c

@@ -37,6 +37,7 @@
 #include <linux/freezer.h>
 #include <linux/namei.h>
 #include <linux/random.h>
+#include <linux/xattr.h>
 #include <net/ipv6.h>
 #include "cifsfs.h"
 #include "cifspdu.h"
@@ -135,6 +136,7 @@ cifs_read_super(struct super_block *sb)
 
 	sb->s_magic = CIFS_MAGIC_NUMBER;
 	sb->s_op = &cifs_super_ops;
+	sb->s_xattr = cifs_xattr_handlers;
 	sb->s_bdi = &cifs_sb->bdi;
 	sb->s_blocksize = CIFS_MAX_MSGSIZE;
 	sb->s_blocksize_bits = 14;	/* default 2**14 = CIFS_MAX_MSGSIZE */
@@ -892,25 +894,21 @@ const struct inode_operations cifs_dir_inode_ops = {
 	.setattr = cifs_setattr,
 	.symlink = cifs_symlink,
 	.mknod   = cifs_mknod,
-#ifdef CONFIG_CIFS_XATTR
-	.setxattr = cifs_setxattr,
-	.getxattr = cifs_getxattr,
+	.setxattr = generic_setxattr,
+	.getxattr = generic_getxattr,
 	.listxattr = cifs_listxattr,
-	.removexattr = cifs_removexattr,
-#endif
+	.removexattr = generic_removexattr,
 };
 
 const struct inode_operations cifs_file_inode_ops = {
 /*	revalidate:cifs_revalidate, */
 	.setattr = cifs_setattr,
 	.getattr = cifs_getattr, /* do we need this anymore? */
 	.permission = cifs_permission,
-#ifdef CONFIG_CIFS_XATTR
-	.setxattr = cifs_setxattr,
-	.getxattr = cifs_getxattr,
+	.setxattr = generic_setxattr,
+	.getxattr = generic_getxattr,
 	.listxattr = cifs_listxattr,
-	.removexattr = cifs_removexattr,
-#endif
+	.removexattr = generic_removexattr,
 };
 
 const struct inode_operations cifs_symlink_inode_ops = {
@@ -920,12 +918,10 @@ const struct inode_operations cifs_symlink_inode_ops = {
 	/* BB add the following two eventually */
 	/* revalidate: cifs_revalidate,
 	   setattr:    cifs_notify_change, *//* BB do we need notify change */
-#ifdef CONFIG_CIFS_XATTR
-	.setxattr = cifs_setxattr,
-	.getxattr = cifs_getxattr,
+	.setxattr = generic_setxattr,
+	.getxattr = generic_getxattr,
 	.listxattr = cifs_listxattr,
-	.removexattr = cifs_removexattr,
-#endif
+	.removexattr = generic_removexattr,
 };
 
 static int cifs_clone_file_range(struct file *src_file, loff_t off,

fs/cifs/cifsfs.h

@@ -120,11 +120,15 @@ extern const char *cifs_get_link(struct dentry *, struct inode *,
 			struct delayed_call *);
 extern int cifs_symlink(struct inode *inode, struct dentry *direntry,
 			const char *symname);
-extern int	cifs_removexattr(struct dentry *, const char *);
-extern int	cifs_setxattr(struct dentry *, const char *, const void *,
-			size_t, int);
-extern ssize_t	cifs_getxattr(struct dentry *, struct inode *, const char *, void *, size_t);
+
+#ifdef CONFIG_CIFS_XATTR
+extern const struct xattr_handler *cifs_xattr_handlers[];
 extern ssize_t	cifs_listxattr(struct dentry *, char *, size_t);
+#else
+# define cifs_xattr_handlers NULL
+# define cifs_listxattr NULL
+#endif
+
 extern long cifs_ioctl(struct file *filep, unsigned int cmd, unsigned long arg);
 #ifdef CONFIG_CIFS_NFSD_EXPORT
 extern const struct export_operations cifs_export_ops;