fs/orangefs/xattr.c - kernel/msm-4.19 - Gitiles

 /*
  * (C) 2001 Clemson University and The University of Chicago
  *
  * See COPYING in top-level directory.
  */

 /*
  *  Linux VFS extended attribute operations.
  */

 #include "protocol.h"
 #include "pvfs2-kernel.h"
 #include "pvfs2-bufmap.h"
 #include <linux/posix_acl_xattr.h>
 #include <linux/xattr.h>


 #define SYSTEM_PVFS2_KEY "system.pvfs2."
 #define SYSTEM_PVFS2_KEY_LEN 13

 /*
  * this function returns
  *   0 if the key corresponding to name is not meant to be printed as part
  *     of a listxattr.
  *   1 if the key corresponding to name is meant to be returned as part of
  *     a listxattr.
  * The ones that start SYSTEM_PVFS2_KEY are the ones to avoid printing.
  */
 static int is_reserved_key(const char *key, size_t size)
 {

 	if (size < SYSTEM_PVFS2_KEY_LEN)
 		return 1;

 	return strncmp(key, SYSTEM_PVFS2_KEY, SYSTEM_PVFS2_KEY_LEN) ?  1 : 0;
 }

 static inline int convert_to_internal_xattr_flags(int setxattr_flags)
 {
 	int internal_flag = 0;

 	if (setxattr_flags & XATTR_REPLACE) {
 		/* Attribute must exist! */
 		internal_flag = PVFS_XATTR_REPLACE;
 	} else if (setxattr_flags & XATTR_CREATE) {
 		/* Attribute must not exist */
 		internal_flag = PVFS_XATTR_CREATE;
 	}
 	return internal_flag;
 }


 /*
  * Tries to get a specified key's attributes of a given
  * file into a user-specified buffer. Note that the getxattr
  * interface allows for the users to probe the size of an
  * extended attribute by passing in a value of 0 to size.
  * Thus our return value is always the size of the attribute
  * unless the key does not exist for the file and/or if
  * there were errors in fetching the attribute value.
  */
 ssize_t pvfs2_inode_getxattr(struct inode *inode, const char *prefix,
 		const char *name, void *buffer, size_t size)
 {
 	struct pvfs2_inode_s *pvfs2_inode = PVFS2_I(inode);
 	struct pvfs2_kernel_op_s *new_op = NULL;
 	ssize_t ret = -ENOMEM;
 	ssize_t length = 0;
 	int fsuid;
 	int fsgid;

 	gossip_debug(GOSSIP_XATTR_DEBUG,
 		     "%s: prefix %s name %s, buffer_size %zd\n",
 		     __func__, prefix, name, size);

 	if (name == NULL || (size > 0 && buffer == NULL)) {
 		gossip_err("pvfs2_inode_getxattr: bogus NULL pointers\n");
 		return -EINVAL;
 	}
 	if (size < 0 ||
 	    (strlen(name) + strlen(prefix)) >= PVFS_MAX_XATTR_NAMELEN) {
 		gossip_err("Invalid size (%d) or key length (%d)\n",
 			   (int)size,
 			   (int)(strlen(name) + strlen(prefix)));
 		return -EINVAL;
 	}

 	fsuid = from_kuid(current_user_ns(), current_fsuid());
 	fsgid = from_kgid(current_user_ns(), current_fsgid());

 	gossip_debug(GOSSIP_XATTR_DEBUG,
 		     "getxattr on inode %pU, name %s "
 		     "(uid %o, gid %o)\n",
 		     get_khandle_from_ino(inode),
 		     name,
 		     fsuid,
 		     fsgid);

 	down_read(&pvfs2_inode->xattr_sem);

 	new_op = op_alloc(PVFS2_VFS_OP_GETXATTR);
 	if (!new_op)
 		goto out_unlock;

 	new_op->upcall.req.getxattr.refn = pvfs2_inode->refn;
 	ret = snprintf((char *)new_op->upcall.req.getxattr.key,
 		       PVFS_MAX_XATTR_NAMELEN, "%s%s", prefix, name);

 	/*
 	 * NOTE: Although keys are meant to be NULL terminated textual
 	 * strings, I am going to explicitly pass the length just in case
 	 * we change this later on...
 	 */
 	new_op->upcall.req.getxattr.key_sz = ret + 1;

 	ret = service_operation(new_op, "pvfs2_inode_getxattr",
 				get_interruptible_flag(inode));
 	if (ret != 0) {
 		if (ret == -ENOENT) {
 			ret = -ENODATA;
 			gossip_debug(GOSSIP_XATTR_DEBUG,
 				     "pvfs2_inode_getxattr: inode %pU key %s"
 				     " does not exist!\n",
 				     get_khandle_from_ino(inode),
 				     (char *)new_op->upcall.req.getxattr.key);
 		}
 		goto out_release_op;
 	}

 	/*
 	 * Length returned includes null terminator.
 	 */
 	length = new_op->downcall.resp.getxattr.val_sz;

 	/*
 	 * Just return the length of the queried attribute.
 	 */
 	if (size == 0) {
 		ret = length;
 		goto out_release_op;
 	}

 	/*
 	 * Check to see if key length is > provided buffer size.
 	 */
 	if (length > size) {
 		ret = -ERANGE;
 		goto out_release_op;
 	}

 	memset(buffer, 0, size);
 	memcpy(buffer, new_op->downcall.resp.getxattr.val, length);
 	gossip_debug(GOSSIP_XATTR_DEBUG,
 	     "pvfs2_inode_getxattr: inode %pU "
 	     "key %s key_sz %d, val_len %d\n",
 	     get_khandle_from_ino(inode),
 	     (char *)new_op->
 		upcall.req.getxattr.key,
 		     (int)new_op->
 		upcall.req.getxattr.key_sz,
 	     (int)ret);

 	ret = length;

 out_release_op:
 	op_release(new_op);
 out_unlock:
 	up_read(&pvfs2_inode->xattr_sem);
 	return ret;
 }

 static int pvfs2_inode_removexattr(struct inode *inode,
 			    const char *prefix,
 			    const char *name,
 			    int flags)
 {
 	struct pvfs2_inode_s *pvfs2_inode = PVFS2_I(inode);
 	struct pvfs2_kernel_op_s *new_op = NULL;
 	int ret = -ENOMEM;

 	down_write(&pvfs2_inode->xattr_sem);
 	new_op = op_alloc(PVFS2_VFS_OP_REMOVEXATTR);
 	if (!new_op)
 		goto out_unlock;

 	new_op->upcall.req.removexattr.refn = pvfs2_inode->refn;
 	/*
 	 * NOTE: Although keys are meant to be NULL terminated
 	 * textual strings, I am going to explicitly pass the
 	 * length just in case we change this later on...
 	 */
 	ret = snprintf((char *)new_op->upcall.req.removexattr.key,
 		       PVFS_MAX_XATTR_NAMELEN,
 		       "%s%s",
 		       (prefix ? prefix : ""),
 		       name);
 	new_op->upcall.req.removexattr.key_sz = ret + 1;

 	gossip_debug(GOSSIP_XATTR_DEBUG,
 		     "pvfs2_inode_removexattr: key %s, key_sz %d\n",
 		     (char *)new_op->upcall.req.removexattr.key,
 		     (int)new_op->upcall.req.removexattr.key_sz);

 	ret = service_operation(new_op,
 				"pvfs2_inode_removexattr",
 				get_interruptible_flag(inode));
 	if (ret == -ENOENT) {
 		/*
 		 * Request to replace a non-existent attribute is an error.
 		 */
 		if (flags & XATTR_REPLACE)
 			ret = -ENODATA;
 		else
 			ret = 0;
 	}

 	gossip_debug(GOSSIP_XATTR_DEBUG,
 		     "pvfs2_inode_removexattr: returning %d\n", ret);

 	op_release(new_op);
 out_unlock:
 	up_write(&pvfs2_inode->xattr_sem);
 	return ret;
 }

 /*
  * Tries to set an attribute for a given key on a file.
  *
  * Returns a -ve number on error and 0 on success.  Key is text, but value
  * can be binary!
  */
 int pvfs2_inode_setxattr(struct inode *inode, const char *prefix,
 		const char *name, const void *value, size_t size, int flags)
 {
 	struct pvfs2_inode_s *pvfs2_inode = PVFS2_I(inode);
 	struct pvfs2_kernel_op_s *new_op;
 	int internal_flag = 0;
 	int ret = -ENOMEM;

 	gossip_debug(GOSSIP_XATTR_DEBUG,
 		     "%s: prefix %s, name %s, buffer_size %zd\n",
 		     __func__, prefix, name, size);

 	if (size < 0 ||
 	    size >= PVFS_MAX_XATTR_VALUELEN ||
 	    flags < 0) {
 		gossip_err("pvfs2_inode_setxattr: bogus values of size(%d), flags(%d)\n",
 			   (int)size,
 			   flags);
 		return -EINVAL;
 	}

 	if (name == NULL ||
 	    (size > 0 && value == NULL)) {
 		gossip_err("pvfs2_inode_setxattr: bogus NULL pointers!\n");
 		return -EINVAL;
 	}

 	internal_flag = convert_to_internal_xattr_flags(flags);

 	if (prefix) {
 		if (strlen(name) + strlen(prefix) >= PVFS_MAX_XATTR_NAMELEN) {
 			gossip_err
 			    ("pvfs2_inode_setxattr: bogus key size (%d)\n",
 			     (int)(strlen(name) + strlen(prefix)));
 			return -EINVAL;
 		}
 	} else {
 		if (strlen(name) >= PVFS_MAX_XATTR_NAMELEN) {
 			gossip_err
 			    ("pvfs2_inode_setxattr: bogus key size (%d)\n",
 			     (int)(strlen(name)));
 			return -EINVAL;
 		}
 	}

 	/* This is equivalent to a removexattr */
 	if (size == 0 && value == NULL) {
 		gossip_debug(GOSSIP_XATTR_DEBUG,
 			     "removing xattr (%s%s)\n",
 			     prefix,
 			     name);
 		return pvfs2_inode_removexattr(inode, prefix, name, flags);
 	}

 	gossip_debug(GOSSIP_XATTR_DEBUG,
 		     "setxattr on inode %pU, name %s\n",
 		     get_khandle_from_ino(inode),
 		     name);

 	down_write(&pvfs2_inode->xattr_sem);
 	new_op = op_alloc(PVFS2_VFS_OP_SETXATTR);
 	if (!new_op)
 		goto out_unlock;


 	new_op->upcall.req.setxattr.refn = pvfs2_inode->refn;
 	new_op->upcall.req.setxattr.flags = internal_flag;
 	/*
 	 * NOTE: Although keys are meant to be NULL terminated textual
 	 * strings, I am going to explicitly pass the length just in
 	 * case we change this later on...
 	 */
 	ret = snprintf((char *)new_op->upcall.req.setxattr.keyval.key,
 		       PVFS_MAX_XATTR_NAMELEN,
 		       "%s%s",
 		       prefix, name);
 	new_op->upcall.req.setxattr.keyval.key_sz = ret + 1;
 	memcpy(new_op->upcall.req.setxattr.keyval.val, value, size);
 	new_op->upcall.req.setxattr.keyval.val_sz = size;

 	gossip_debug(GOSSIP_XATTR_DEBUG,
 		     "pvfs2_inode_setxattr: key %s, key_sz %d "
 		     " value size %zd\n",
 		     (char *)new_op->upcall.req.setxattr.keyval.key,
 		     (int)new_op->upcall.req.setxattr.keyval.key_sz,
 		     size);

 	ret = service_operation(new_op,
 				"pvfs2_inode_setxattr",
 				get_interruptible_flag(inode));

 	gossip_debug(GOSSIP_XATTR_DEBUG,
 		     "pvfs2_inode_setxattr: returning %d\n",
 		     ret);

 	/* when request is serviced properly, free req op struct */
 	op_release(new_op);
 out_unlock:
 	up_write(&pvfs2_inode->xattr_sem);
 	return ret;
 }

 /*
  * Tries to get a specified object's keys into a user-specified buffer of a
  * given size.  Note that like the previous instances of xattr routines, this
  * also allows you to pass in a NULL pointer and 0 size to probe the size for
  * subsequent memory allocations. Thus our return value is always the size of
  * all the keys unless there were errors in fetching the keys!
  */
 ssize_t pvfs2_listxattr(struct dentry *dentry, char *buffer, size_t size)
 {
 	struct inode *inode = dentry->d_inode;
 	struct pvfs2_inode_s *pvfs2_inode = PVFS2_I(inode);
 	struct pvfs2_kernel_op_s *new_op;
 	__u64 token = PVFS_ITERATE_START;
 	ssize_t ret = -ENOMEM;
 	ssize_t total = 0;
 	ssize_t length = 0;
 	int count_keys = 0;
 	int key_size;
 	int i = 0;

 	if (size > 0 && buffer == NULL) {
 		gossip_err("%s: bogus NULL pointers\n", __func__);
 		return -EINVAL;
 	}
 	if (size < 0) {
 		gossip_err("Invalid size (%d)\n", (int)size);
 		return -EINVAL;
 	}

 	down_read(&pvfs2_inode->xattr_sem);
 	new_op = op_alloc(PVFS2_VFS_OP_LISTXATTR);
 	if (!new_op)
 		goto out_unlock;

 	if (buffer && size > 0)
 		memset(buffer, 0, size);

 try_again:
 	key_size = 0;
 	new_op->upcall.req.listxattr.refn = pvfs2_inode->refn;
 	new_op->upcall.req.listxattr.token = token;
 	new_op->upcall.req.listxattr.requested_count =
 	    (size == 0) ? 0 : PVFS_MAX_XATTR_LISTLEN;
 	ret = service_operation(new_op, __func__,
 				get_interruptible_flag(inode));
 	if (ret != 0)
 		goto done;

 	if (size == 0) {
 		/*
 		 * This is a bit of a big upper limit, but I did not want to
 		 * spend too much time getting this correct, since users end
 		 * up allocating memory rather than us...
 		 */
 		total = new_op->downcall.resp.listxattr.returned_count *
 			PVFS_MAX_XATTR_NAMELEN;
 		goto done;
 	}

 	length = new_op->downcall.resp.listxattr.keylen;
 	if (length == 0)
 		goto done;

 	/*
 	 * Check to see how much can be fit in the buffer. Fit only whole keys.
 	 */
 	for (i = 0; i < new_op->downcall.resp.listxattr.returned_count; i++) {
 		if (total + new_op->downcall.resp.listxattr.lengths[i] > size)
 			goto done;

 		/*
 		 * Since many dumb programs try to setxattr() on our reserved
 		 * xattrs this is a feeble attempt at defeating those by not
 		 * listing them in the output of listxattr.. sigh
 		 */
 		if (is_reserved_key(new_op->downcall.resp.listxattr.key +
 				    key_size,
 				    new_op->downcall.resp.
 					listxattr.lengths[i])) {
 			gossip_debug(GOSSIP_XATTR_DEBUG, "Copying key %d -> %s\n",
 					i, new_op->downcall.resp.listxattr.key +
 						key_size);
 			memcpy(buffer + total,
 				new_op->downcall.resp.listxattr.key + key_size,
 				new_op->downcall.resp.listxattr.lengths[i]);
 			total += new_op->downcall.resp.listxattr.lengths[i];
 			count_keys++;
 		} else {
 			gossip_debug(GOSSIP_XATTR_DEBUG, "[RESERVED] key %d -> %s\n",
 					i, new_op->downcall.resp.listxattr.key +
 						key_size);
 		}
 		key_size += new_op->downcall.resp.listxattr.lengths[i];
 	}

 	/*
 	 * Since the buffer was large enough, we might have to continue
 	 * fetching more keys!
 	 */
 	token = new_op->downcall.resp.listxattr.token;
 	if (token != PVFS_ITERATE_END)
 		goto try_again;

 done:
 	gossip_debug(GOSSIP_XATTR_DEBUG, "%s: returning %d"
 		     " [size of buffer %ld] (filled in %d keys)\n",
 		     __func__,
 		     ret ? (int)ret : (int)total,
 		     (long)size,
 		     count_keys);
 	op_release(new_op);
 	if (ret == 0)
 		ret = total;
 out_unlock:
 	up_read(&pvfs2_inode->xattr_sem);
 	return ret;
 }

 int pvfs2_xattr_set_default(struct dentry *dentry,
 			    const char *name,
 			    const void *buffer,
 			    size_t size,
 			    int flags,
 			    int handler_flags)
 {
 	return pvfs2_inode_setxattr(dentry->d_inode,
 				    PVFS2_XATTR_NAME_DEFAULT_PREFIX,
 				    name,
 				    buffer,
 				    size,
 				    flags);
 }

 int pvfs2_xattr_get_default(struct dentry *dentry,
 			    const char *name,
 			    void *buffer,
 			    size_t size,
 			    int handler_flags)
 {
 	return pvfs2_inode_getxattr(dentry->d_inode,
 				    PVFS2_XATTR_NAME_DEFAULT_PREFIX,
 				    name,
 				    buffer,
 				    size);

 }

 static int pvfs2_xattr_set_trusted(struct dentry *dentry,
 			    const char *name,
 			    const void *buffer,
 			    size_t size,
 			    int flags,
 			    int handler_flags)
 {
 	return pvfs2_inode_setxattr(dentry->d_inode,
 				    PVFS2_XATTR_NAME_TRUSTED_PREFIX,
 				    name,
 				    buffer,
 				    size,
 				    flags);
 }

 static int pvfs2_xattr_get_trusted(struct dentry *dentry,
 			    const char *name,
 			    void *buffer,
 			    size_t size,
 			    int handler_flags)
 {
 	return pvfs2_inode_getxattr(dentry->d_inode,
 				    PVFS2_XATTR_NAME_TRUSTED_PREFIX,
 				    name,
 				    buffer,
 				    size);
 }

 static struct xattr_handler pvfs2_xattr_trusted_handler = {
 	.prefix = PVFS2_XATTR_NAME_TRUSTED_PREFIX,
 	.get = pvfs2_xattr_get_trusted,
 	.set = pvfs2_xattr_set_trusted,
 };

 static struct xattr_handler pvfs2_xattr_default_handler = {
 	/*
 	 * NOTE: this is set to be the empty string.
 	 * so that all un-prefixed xattrs keys get caught
 	 * here!
 	 */
 	.prefix = PVFS2_XATTR_NAME_DEFAULT_PREFIX,
 	.get = pvfs2_xattr_get_default,
 	.set = pvfs2_xattr_set_default,
 };

 const struct xattr_handler *pvfs2_xattr_handlers[] = {
 	&posix_acl_access_xattr_handler,
 	&posix_acl_default_xattr_handler,
 	&pvfs2_xattr_trusted_handler,
 	&pvfs2_xattr_default_handler,
 	NULL
 };
	/*
	* (C) 2001 Clemson University and The University of Chicago
	*
	* See COPYING in top-level directory.
	*/

	/*
	* Linux VFS extended attribute operations.
	*/

	#include "protocol.h"
	#include "pvfs2-kernel.h"
	#include "pvfs2-bufmap.h"
	#include <linux/posix_acl_xattr.h>
	#include <linux/xattr.h>


	#define SYSTEM_PVFS2_KEY "system.pvfs2."
	#define SYSTEM_PVFS2_KEY_LEN 13

	/*
	* this function returns
	* 0 if the key corresponding to name is not meant to be printed as part
	* of a listxattr.
	* 1 if the key corresponding to name is meant to be returned as part of
	* a listxattr.
	* The ones that start SYSTEM_PVFS2_KEY are the ones to avoid printing.
	*/
	static int is_reserved_key(const char *key, size_t size)
	{

	if (size < SYSTEM_PVFS2_KEY_LEN)
	return 1;

	return strncmp(key, SYSTEM_PVFS2_KEY, SYSTEM_PVFS2_KEY_LEN) ? 1 : 0;
	}

	static inline int convert_to_internal_xattr_flags(int setxattr_flags)
	{
	int internal_flag = 0;

	if (setxattr_flags & XATTR_REPLACE) {
	/* Attribute must exist! */
	internal_flag = PVFS_XATTR_REPLACE;
	} else if (setxattr_flags & XATTR_CREATE) {
	/* Attribute must not exist */
	internal_flag = PVFS_XATTR_CREATE;
	}
	return internal_flag;
	}


	/*
	* Tries to get a specified key's attributes of a given
	* file into a user-specified buffer. Note that the getxattr
	* interface allows for the users to probe the size of an
	* extended attribute by passing in a value of 0 to size.
	* Thus our return value is always the size of the attribute
	* unless the key does not exist for the file and/or if
	* there were errors in fetching the attribute value.
	*/
	ssize_t pvfs2_inode_getxattr(struct inode inode, const char prefix,
	const char name, void buffer, size_t size)
	{
	struct pvfs2_inode_s *pvfs2_inode = PVFS2_I(inode);
	struct pvfs2_kernel_op_s *new_op = NULL;
	ssize_t ret = -ENOMEM;
	ssize_t length = 0;
	int fsuid;
	int fsgid;

	gossip_debug(GOSSIP_XATTR_DEBUG,
	"%s: prefix %s name %s, buffer_size %zd\n",
	__func__, prefix, name, size);

	if (name == NULL \|\| (size > 0 && buffer == NULL)) {
	gossip_err("pvfs2_inode_getxattr: bogus NULL pointers\n");
	return -EINVAL;
	}
	if (size < 0 \|\|
	(strlen(name) + strlen(prefix)) >= PVFS_MAX_XATTR_NAMELEN) {
	gossip_err("Invalid size (%d) or key length (%d)\n",
	(int)size,
	(int)(strlen(name) + strlen(prefix)));
	return -EINVAL;
	}

	fsuid = from_kuid(current_user_ns(), current_fsuid());
	fsgid = from_kgid(current_user_ns(), current_fsgid());

	gossip_debug(GOSSIP_XATTR_DEBUG,
	"getxattr on inode %pU, name %s "
	"(uid %o, gid %o)\n",
	get_khandle_from_ino(inode),
	name,
	fsuid,
	fsgid);

	down_read(&pvfs2_inode->xattr_sem);

	new_op = op_alloc(PVFS2_VFS_OP_GETXATTR);
	if (!new_op)
	goto out_unlock;

	new_op->upcall.req.getxattr.refn = pvfs2_inode->refn;
	ret = snprintf((char *)new_op->upcall.req.getxattr.key,
	PVFS_MAX_XATTR_NAMELEN, "%s%s", prefix, name);

	/*
	* NOTE: Although keys are meant to be NULL terminated textual
	* strings, I am going to explicitly pass the length just in case
	* we change this later on...
	*/
	new_op->upcall.req.getxattr.key_sz = ret + 1;

	ret = service_operation(new_op, "pvfs2_inode_getxattr",
	get_interruptible_flag(inode));
	if (ret != 0) {
	if (ret == -ENOENT) {
	ret = -ENODATA;
	gossip_debug(GOSSIP_XATTR_DEBUG,
	"pvfs2_inode_getxattr: inode %pU key %s"
	" does not exist!\n",
	get_khandle_from_ino(inode),
	(char *)new_op->upcall.req.getxattr.key);
	}
	goto out_release_op;
	}

	/*
	* Length returned includes null terminator.
	*/
	length = new_op->downcall.resp.getxattr.val_sz;

	/*
	* Just return the length of the queried attribute.
	*/
	if (size == 0) {
	ret = length;
	goto out_release_op;
	}

	/*
	* Check to see if key length is > provided buffer size.
	*/
	if (length > size) {
	ret = -ERANGE;
	goto out_release_op;
	}

	memset(buffer, 0, size);
	memcpy(buffer, new_op->downcall.resp.getxattr.val, length);
	gossip_debug(GOSSIP_XATTR_DEBUG,
	"pvfs2_inode_getxattr: inode %pU "
	"key %s key_sz %d, val_len %d\n",
	get_khandle_from_ino(inode),
	(char *)new_op->
	upcall.req.getxattr.key,
	(int)new_op->
	upcall.req.getxattr.key_sz,
	(int)ret);

	ret = length;

	out_release_op:
	op_release(new_op);
	out_unlock:
	up_read(&pvfs2_inode->xattr_sem);
	return ret;
	}

	static int pvfs2_inode_removexattr(struct inode *inode,
	const char *prefix,
	const char *name,
	int flags)
	{
	struct pvfs2_inode_s *pvfs2_inode = PVFS2_I(inode);
	struct pvfs2_kernel_op_s *new_op = NULL;
	int ret = -ENOMEM;

	down_write(&pvfs2_inode->xattr_sem);
	new_op = op_alloc(PVFS2_VFS_OP_REMOVEXATTR);
	if (!new_op)
	goto out_unlock;

	new_op->upcall.req.removexattr.refn = pvfs2_inode->refn;
	/*
	* NOTE: Although keys are meant to be NULL terminated
	* textual strings, I am going to explicitly pass the
	* length just in case we change this later on...
	*/
	ret = snprintf((char *)new_op->upcall.req.removexattr.key,
	PVFS_MAX_XATTR_NAMELEN,
	"%s%s",
	(prefix ? prefix : ""),
	name);
	new_op->upcall.req.removexattr.key_sz = ret + 1;

	gossip_debug(GOSSIP_XATTR_DEBUG,
	"pvfs2_inode_removexattr: key %s, key_sz %d\n",
	(char *)new_op->upcall.req.removexattr.key,
	(int)new_op->upcall.req.removexattr.key_sz);

	ret = service_operation(new_op,
	"pvfs2_inode_removexattr",
	get_interruptible_flag(inode));
	if (ret == -ENOENT) {
	/*
	* Request to replace a non-existent attribute is an error.
	*/
	if (flags & XATTR_REPLACE)
	ret = -ENODATA;
	else
	ret = 0;
	}

	gossip_debug(GOSSIP_XATTR_DEBUG,
	"pvfs2_inode_removexattr: returning %d\n", ret);

	op_release(new_op);
	out_unlock:
	up_write(&pvfs2_inode->xattr_sem);
	return ret;
	}

	/*
	* Tries to set an attribute for a given key on a file.
	*
	* Returns a -ve number on error and 0 on success. Key is text, but value
	* can be binary!
	*/
	int pvfs2_inode_setxattr(struct inode inode, const char prefix,
	const char name, const void value, size_t size, int flags)
	{
	struct pvfs2_inode_s *pvfs2_inode = PVFS2_I(inode);
	struct pvfs2_kernel_op_s *new_op;
	int internal_flag = 0;
	int ret = -ENOMEM;

	gossip_debug(GOSSIP_XATTR_DEBUG,
	"%s: prefix %s, name %s, buffer_size %zd\n",
	__func__, prefix, name, size);

	if (size < 0 \|\|
	size >= PVFS_MAX_XATTR_VALUELEN \|\|
	flags < 0) {
	gossip_err("pvfs2_inode_setxattr: bogus values of size(%d), flags(%d)\n",
	(int)size,
	flags);
	return -EINVAL;
	}

	if (name == NULL \|\|
	(size > 0 && value == NULL)) {
	gossip_err("pvfs2_inode_setxattr: bogus NULL pointers!\n");
	return -EINVAL;
	}

	internal_flag = convert_to_internal_xattr_flags(flags);

	if (prefix) {
	if (strlen(name) + strlen(prefix) >= PVFS_MAX_XATTR_NAMELEN) {
	gossip_err
	("pvfs2_inode_setxattr: bogus key size (%d)\n",
	(int)(strlen(name) + strlen(prefix)));
	return -EINVAL;
	}
	} else {
	if (strlen(name) >= PVFS_MAX_XATTR_NAMELEN) {
	gossip_err
	("pvfs2_inode_setxattr: bogus key size (%d)\n",
	(int)(strlen(name)));
	return -EINVAL;
	}
	}

	/* This is equivalent to a removexattr */
	if (size == 0 && value == NULL) {
	gossip_debug(GOSSIP_XATTR_DEBUG,
	"removing xattr (%s%s)\n",
	prefix,
	name);
	return pvfs2_inode_removexattr(inode, prefix, name, flags);
	}

	gossip_debug(GOSSIP_XATTR_DEBUG,
	"setxattr on inode %pU, name %s\n",
	get_khandle_from_ino(inode),
	name);

	down_write(&pvfs2_inode->xattr_sem);
	new_op = op_alloc(PVFS2_VFS_OP_SETXATTR);
	if (!new_op)
	goto out_unlock;


	new_op->upcall.req.setxattr.refn = pvfs2_inode->refn;
	new_op->upcall.req.setxattr.flags = internal_flag;
	/*
	* NOTE: Although keys are meant to be NULL terminated textual
	* strings, I am going to explicitly pass the length just in
	* case we change this later on...
	*/
	ret = snprintf((char *)new_op->upcall.req.setxattr.keyval.key,
	PVFS_MAX_XATTR_NAMELEN,
	"%s%s",
	prefix, name);
	new_op->upcall.req.setxattr.keyval.key_sz = ret + 1;
	memcpy(new_op->upcall.req.setxattr.keyval.val, value, size);
	new_op->upcall.req.setxattr.keyval.val_sz = size;

	gossip_debug(GOSSIP_XATTR_DEBUG,
	"pvfs2_inode_setxattr: key %s, key_sz %d "
	" value size %zd\n",
	(char *)new_op->upcall.req.setxattr.keyval.key,
	(int)new_op->upcall.req.setxattr.keyval.key_sz,
	size);

	ret = service_operation(new_op,
	"pvfs2_inode_setxattr",
	get_interruptible_flag(inode));

	gossip_debug(GOSSIP_XATTR_DEBUG,
	"pvfs2_inode_setxattr: returning %d\n",
	ret);

	/* when request is serviced properly, free req op struct */
	op_release(new_op);
	out_unlock:
	up_write(&pvfs2_inode->xattr_sem);
	return ret;
	}

	/*
	* Tries to get a specified object's keys into a user-specified buffer of a
	* given size. Note that like the previous instances of xattr routines, this
	* also allows you to pass in a NULL pointer and 0 size to probe the size for
	* subsequent memory allocations. Thus our return value is always the size of
	* all the keys unless there were errors in fetching the keys!
	*/
	ssize_t pvfs2_listxattr(struct dentry dentry, char buffer, size_t size)
	{
	struct inode *inode = dentry->d_inode;
	struct pvfs2_inode_s *pvfs2_inode = PVFS2_I(inode);
	struct pvfs2_kernel_op_s *new_op;
	__u64 token = PVFS_ITERATE_START;
	ssize_t ret = -ENOMEM;
	ssize_t total = 0;
	ssize_t length = 0;
	int count_keys = 0;
	int key_size;
	int i = 0;

	if (size > 0 && buffer == NULL) {
	gossip_err("%s: bogus NULL pointers\n", __func__);
	return -EINVAL;
	}
	if (size < 0) {
	gossip_err("Invalid size (%d)\n", (int)size);
	return -EINVAL;
	}

	down_read(&pvfs2_inode->xattr_sem);
	new_op = op_alloc(PVFS2_VFS_OP_LISTXATTR);
	if (!new_op)
	goto out_unlock;

	if (buffer && size > 0)
	memset(buffer, 0, size);

	try_again:
	key_size = 0;
	new_op->upcall.req.listxattr.refn = pvfs2_inode->refn;
	new_op->upcall.req.listxattr.token = token;
	new_op->upcall.req.listxattr.requested_count =
	(size == 0) ? 0 : PVFS_MAX_XATTR_LISTLEN;
	ret = service_operation(new_op, __func__,
	get_interruptible_flag(inode));
	if (ret != 0)
	goto done;

	if (size == 0) {
	/*
	* This is a bit of a big upper limit, but I did not want to
	* spend too much time getting this correct, since users end
	* up allocating memory rather than us...
	*/
	total = new_op->downcall.resp.listxattr.returned_count *
	PVFS_MAX_XATTR_NAMELEN;
	goto done;
	}

	length = new_op->downcall.resp.listxattr.keylen;
	if (length == 0)
	goto done;

	/*
	* Check to see how much can be fit in the buffer. Fit only whole keys.
	*/
	for (i = 0; i < new_op->downcall.resp.listxattr.returned_count; i++) {
	if (total + new_op->downcall.resp.listxattr.lengths[i] > size)
	goto done;

	/*
	* Since many dumb programs try to setxattr() on our reserved
	* xattrs this is a feeble attempt at defeating those by not
	* listing them in the output of listxattr.. sigh
	*/
	if (is_reserved_key(new_op->downcall.resp.listxattr.key +
	key_size,
	new_op->downcall.resp.
	listxattr.lengths[i])) {
	gossip_debug(GOSSIP_XATTR_DEBUG, "Copying key %d -> %s\n",
	i, new_op->downcall.resp.listxattr.key +
	key_size);
	memcpy(buffer + total,
	new_op->downcall.resp.listxattr.key + key_size,
	new_op->downcall.resp.listxattr.lengths[i]);
	total += new_op->downcall.resp.listxattr.lengths[i];
	count_keys++;
	} else {
	gossip_debug(GOSSIP_XATTR_DEBUG, "[RESERVED] key %d -> %s\n",
	i, new_op->downcall.resp.listxattr.key +
	key_size);
	}
	key_size += new_op->downcall.resp.listxattr.lengths[i];
	}

	/*
	* Since the buffer was large enough, we might have to continue
	* fetching more keys!
	*/
	token = new_op->downcall.resp.listxattr.token;
	if (token != PVFS_ITERATE_END)
	goto try_again;

	done:
	gossip_debug(GOSSIP_XATTR_DEBUG, "%s: returning %d"
	" [size of buffer %ld] (filled in %d keys)\n",
	__func__,
	ret ? (int)ret : (int)total,
	(long)size,
	count_keys);
	op_release(new_op);
	if (ret == 0)
	ret = total;
	out_unlock:
	up_read(&pvfs2_inode->xattr_sem);
	return ret;
	}

	int pvfs2_xattr_set_default(struct dentry *dentry,
	const char *name,
	const void *buffer,
	size_t size,
	int flags,
	int handler_flags)
	{
	return pvfs2_inode_setxattr(dentry->d_inode,
	PVFS2_XATTR_NAME_DEFAULT_PREFIX,
	name,
	buffer,
	size,
	flags);
	}

	int pvfs2_xattr_get_default(struct dentry *dentry,
	const char *name,
	void *buffer,
	size_t size,
	int handler_flags)
	{
	return pvfs2_inode_getxattr(dentry->d_inode,
	PVFS2_XATTR_NAME_DEFAULT_PREFIX,
	name,
	buffer,
	size);

	}

	static int pvfs2_xattr_set_trusted(struct dentry *dentry,
	const char *name,
	const void *buffer,
	size_t size,
	int flags,
	int handler_flags)
	{
	return pvfs2_inode_setxattr(dentry->d_inode,
	PVFS2_XATTR_NAME_TRUSTED_PREFIX,
	name,
	buffer,
	size,
	flags);
	}

	static int pvfs2_xattr_get_trusted(struct dentry *dentry,
	const char *name,
	void *buffer,
	size_t size,
	int handler_flags)
	{
	return pvfs2_inode_getxattr(dentry->d_inode,
	PVFS2_XATTR_NAME_TRUSTED_PREFIX,
	name,
	buffer,
	size);
	}

	static struct xattr_handler pvfs2_xattr_trusted_handler = {
	.prefix = PVFS2_XATTR_NAME_TRUSTED_PREFIX,
	.get = pvfs2_xattr_get_trusted,
	.set = pvfs2_xattr_set_trusted,
	};

	static struct xattr_handler pvfs2_xattr_default_handler = {
	/*
	* NOTE: this is set to be the empty string.
	* so that all un-prefixed xattrs keys get caught
	* here!
	*/
	.prefix = PVFS2_XATTR_NAME_DEFAULT_PREFIX,
	.get = pvfs2_xattr_get_default,
	.set = pvfs2_xattr_set_default,
	};

	const struct xattr_handler *pvfs2_xattr_handlers[] = {
	&posix_acl_access_xattr_handler,
	&posix_acl_default_xattr_handler,
	&pvfs2_xattr_trusted_handler,
	&pvfs2_xattr_default_handler,
	NULL
	};