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Commit aa7c5241 authored by Andreas Gruenbacher's avatar Andreas Gruenbacher Committed by Al Viro
Browse files

tmpfs: Use xattr handler infrastructure 



Use the VFS xattr handler infrastructure and get rid of similar code in
the filesystem.  For implementing shmem_xattr_handler_set, we need a
version of simple_xattr_set which removes the attribute when value is
NULL.  Use this to implement kernfs_iop_removexattr as well.

Signed-off-by: default avatarAndreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: default avatarJames Morris <james.l.morris@oracle.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: linux-mm@kvack.org
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 9172abbc

fs/kernfs/inode.c

+1 −1
Original line number Diff line number Diff line
@@ -205,7 +205,7 @@ int kernfs_iop_removexattr(struct dentry *dentry, const char *name) 
	if (!attrs)

		return -ENOMEM;



	return simple_xattr_remove(&attrs->xattrs, name);

	return simple_xattr_set(&attrs->xattrs, name, NULL, 0, XATTR_REPLACE);

}



ssize_t kernfs_iop_getxattr(struct dentry *dentry, const char *name, void *buf,

fs/xattr.c

+16 −32
Original line number Diff line number Diff line
@@ -851,7 +851,21 @@ int simple_xattr_get(struct simple_xattrs *xattrs, const char *name, 
	return ret;

}



static int __simple_xattr_set(struct simple_xattrs *xattrs, const char *name,

/**

 * simple_xattr_set - xattr SET operation for in-memory/pseudo filesystems

 * @xattrs: target simple_xattr list

 * @name: name of the extended attribute

 * @value: value of the xattr. If %NULL, will remove the attribute.

 * @size: size of the new xattr

 * @flags: %XATTR_{CREATE|REPLACE}

 *

 * %XATTR_CREATE is set, the xattr shouldn't exist already; otherwise fails

 * with -EEXIST.  If %XATTR_REPLACE is set, the xattr should exist;

 * otherwise, fails with -ENODATA.

 *

 * Returns 0 on success, -errno on failure.

 */

int simple_xattr_set(struct simple_xattrs *xattrs, const char *name,

		     const void *value, size_t size, int flags)

{

	struct simple_xattr *xattr;
@@ -902,36 +916,6 @@ static int __simple_xattr_set(struct simple_xattrs *xattrs, const char *name, 


}



/**

 * simple_xattr_set - xattr SET operation for in-memory/pseudo filesystems

 * @xattrs: target simple_xattr list

 * @name: name of the new extended attribute

 * @value: value of the new xattr. If %NULL, will remove the attribute

 * @size: size of the new xattr

 * @flags: %XATTR_{CREATE|REPLACE}

 *

 * %XATTR_CREATE is set, the xattr shouldn't exist already; otherwise fails

 * with -EEXIST.  If %XATTR_REPLACE is set, the xattr should exist;

 * otherwise, fails with -ENODATA.

 *

 * Returns 0 on success, -errno on failure.

 */

int simple_xattr_set(struct simple_xattrs *xattrs, const char *name,

		     const void *value, size_t size, int flags)

{

	if (size == 0)

		value = ""; /* empty EA, do not remove */

	return __simple_xattr_set(xattrs, name, value, size, flags);

}



/*

 * xattr REMOVE operation for in-memory/pseudo filesystems

 */

int simple_xattr_remove(struct simple_xattrs *xattrs, const char *name)

{

	return __simple_xattr_set(xattrs, name, NULL, 0, XATTR_REPLACE);

}



static bool xattr_is_trusted(const char *name)

{

	return !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN);

include/linux/xattr.h

+1 −3
Original line number Diff line number Diff line
@@ -104,9 +104,7 @@ int simple_xattr_get(struct simple_xattrs *xattrs, const char *name, 
		     void *buffer, size_t size);

int simple_xattr_set(struct simple_xattrs *xattrs, const char *name,

		     const void *value, size_t size, int flags);

int simple_xattr_remove(struct simple_xattrs *xattrs, const char *name);

ssize_t simple_xattr_list(struct simple_xattrs *xattrs, char *buffer,

			  size_t size);

ssize_t simple_xattr_list(struct simple_xattrs *xattrs, char *buffer, size_t size);

void simple_xattr_list_add(struct simple_xattrs *xattrs,

			   struct simple_xattr *new_xattr);

mm/shmem.c

+42 −89
Original line number Diff line number Diff line
@@ -2561,94 +2561,47 @@ static int shmem_initxattrs(struct inode *inode, 
	return 0;

}



static const struct xattr_handler *shmem_xattr_handlers[] = {

#ifdef CONFIG_TMPFS_POSIX_ACL

	&posix_acl_access_xattr_handler,

	&posix_acl_default_xattr_handler,

#endif

	NULL

};



static int shmem_xattr_validate(const char *name)

{

	struct { const char *prefix; size_t len; } arr[] = {

		{ XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN },

		{ XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN }

	};

	int i;



	for (i = 0; i < ARRAY_SIZE(arr); i++) {

		size_t preflen = arr[i].len;

		if (strncmp(name, arr[i].prefix, preflen) == 0) {

			if (!name[preflen])

				return -EINVAL;

			return 0;

		}

	}

	return -EOPNOTSUPP;

}



static ssize_t shmem_getxattr(struct dentry *dentry, const char *name,

static int shmem_xattr_handler_get(const struct xattr_handler *handler,

				   struct dentry *dentry, const char *name,

				   void *buffer, size_t size)

{

	struct shmem_inode_info *info = SHMEM_I(d_inode(dentry));

	int err;



	/*

	 * If this is a request for a synthetic attribute in the system.*

	 * namespace use the generic infrastructure to resolve a handler

	 * for it via sb->s_xattr.

	 */

	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))

		return generic_getxattr(dentry, name, buffer, size);



	err = shmem_xattr_validate(name);

	if (err)

		return err;



	name = xattr_full_name(handler, name);

	return simple_xattr_get(&info->xattrs, name, buffer, size);

}



static int shmem_setxattr(struct dentry *dentry, const char *name,

static int shmem_xattr_handler_set(const struct xattr_handler *handler,

				   struct dentry *dentry, const char *name,

				   const void *value, size_t size, int flags)

{

	struct shmem_inode_info *info = SHMEM_I(d_inode(dentry));

	int err;



	/*

	 * If this is a request for a synthetic attribute in the system.*

	 * namespace use the generic infrastructure to resolve a handler

	 * for it via sb->s_xattr.

	 */

	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))

		return generic_setxattr(dentry, name, value, size, flags);



	err = shmem_xattr_validate(name);

	if (err)

		return err;



	name = xattr_full_name(handler, name);

	return simple_xattr_set(&info->xattrs, name, value, size, flags);

}



static int shmem_removexattr(struct dentry *dentry, const char *name)

{

	struct shmem_inode_info *info = SHMEM_I(d_inode(dentry));

	int err;



	/*

	 * If this is a request for a synthetic attribute in the system.*

	 * namespace use the generic infrastructure to resolve a handler

	 * for it via sb->s_xattr.

	 */

	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))

		return generic_removexattr(dentry, name);

static const struct xattr_handler shmem_security_xattr_handler = {

	.prefix = XATTR_SECURITY_PREFIX,

	.get = shmem_xattr_handler_get,

	.set = shmem_xattr_handler_set,

};



	err = shmem_xattr_validate(name);

	if (err)

		return err;

static const struct xattr_handler shmem_trusted_xattr_handler = {

	.prefix = XATTR_TRUSTED_PREFIX,

	.get = shmem_xattr_handler_get,

	.set = shmem_xattr_handler_set,

};



	return simple_xattr_remove(&info->xattrs, name);

}

static const struct xattr_handler *shmem_xattr_handlers[] = {

#ifdef CONFIG_TMPFS_POSIX_ACL

	&posix_acl_access_xattr_handler,

	&posix_acl_default_xattr_handler,

#endif

	&shmem_security_xattr_handler,

	&shmem_trusted_xattr_handler,

	NULL

};



static ssize_t shmem_listxattr(struct dentry *dentry, char *buffer, size_t size)

{
@@ -2661,10 +2614,10 @@ static const struct inode_operations shmem_short_symlink_operations = { 
	.readlink	= generic_readlink,

	.follow_link	= simple_follow_link,

#ifdef CONFIG_TMPFS_XATTR

	.setxattr	= shmem_setxattr,

	.getxattr	= shmem_getxattr,

	.setxattr	= generic_setxattr,

	.getxattr	= generic_getxattr,

	.listxattr	= shmem_listxattr,

	.removexattr	= shmem_removexattr,

	.removexattr	= generic_removexattr,

#endif

};
@@ -2673,10 +2626,10 @@ static const struct inode_operations shmem_symlink_inode_operations = { 
	.follow_link	= shmem_follow_link,

	.put_link	= shmem_put_link,

#ifdef CONFIG_TMPFS_XATTR

	.setxattr	= shmem_setxattr,

	.getxattr	= shmem_getxattr,

	.setxattr	= generic_setxattr,

	.getxattr	= generic_getxattr,

	.listxattr	= shmem_listxattr,

	.removexattr	= shmem_removexattr,

	.removexattr	= generic_removexattr,

#endif

};
@@ -3148,10 +3101,10 @@ static const struct inode_operations shmem_inode_operations = { 
	.getattr	= shmem_getattr,

	.setattr	= shmem_setattr,

#ifdef CONFIG_TMPFS_XATTR

	.setxattr	= shmem_setxattr,

	.getxattr	= shmem_getxattr,

	.setxattr	= generic_setxattr,

	.getxattr	= generic_getxattr,

	.listxattr	= shmem_listxattr,

	.removexattr	= shmem_removexattr,

	.removexattr	= generic_removexattr,

	.set_acl	= simple_set_acl,

#endif

};
@@ -3170,10 +3123,10 @@ static const struct inode_operations shmem_dir_inode_operations = { 
	.tmpfile	= shmem_tmpfile,

#endif

#ifdef CONFIG_TMPFS_XATTR

	.setxattr	= shmem_setxattr,

	.getxattr	= shmem_getxattr,

	.setxattr	= generic_setxattr,

	.getxattr	= generic_getxattr,

	.listxattr	= shmem_listxattr,

	.removexattr	= shmem_removexattr,

	.removexattr	= generic_removexattr,

#endif

#ifdef CONFIG_TMPFS_POSIX_ACL

	.setattr	= shmem_setattr,
@@ -3183,10 +3136,10 @@ static const struct inode_operations shmem_dir_inode_operations = { 


static const struct inode_operations shmem_special_inode_operations = {

#ifdef CONFIG_TMPFS_XATTR

	.setxattr	= shmem_setxattr,

	.getxattr	= shmem_getxattr,

	.setxattr	= generic_setxattr,

	.getxattr	= generic_getxattr,

	.listxattr	= shmem_listxattr,

	.removexattr	= shmem_removexattr,

	.removexattr	= generic_removexattr,

#endif

#ifdef CONFIG_TMPFS_POSIX_ACL

	.setattr	= shmem_setattr,