1 files changed, 345 insertions, 259 deletions

diff --git a/fs/btrfs/xattr.c b/fs/btrfs/xattr.c
index 05740b9789e4..ab55d10bd71f 100644
--- a/fs/btrfs/xattr.c
+++ b/fs/btrfs/xattr.c
@@ -1,19 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright (C) 2007 Red Hat.  All rights reserved.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public
- * License v2 as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public
- * License along with this program; if not, write to the
- * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- * Boston, MA 021110-1307, USA.
  */
 
 #include <linux/init.h>
@@ -22,21 +9,28 @@
 #include <linux/rwsem.h>
 #include <linux/xattr.h>
 #include <linux/security.h>
+#include <linux/posix_acl_xattr.h>
+#include <linux/iversion.h>
+#include <linux/sched/mm.h>
 #include "ctree.h"
+#include "fs.h"
+#include "messages.h"
 #include "btrfs_inode.h"
 #include "transaction.h"
 #include "xattr.h"
 #include "disk-io.h"
+#include "props.h"
+#include "locking.h"
+#include "accessors.h"
+#include "dir-item.h"
 
-
-ssize_t __btrfs_getxattr(struct inode *inode, const char *name,
+int btrfs_getxattr(const struct inode *inode, const char *name,
 				void *buffer, size_t size)
 {
 	struct btrfs_dir_item *di;
 	struct btrfs_root *root = BTRFS_I(inode)->root;
-	struct btrfs_path *path;
+	BTRFS_PATH_AUTO_FREE(path);
 	struct extent_buffer *leaf;
-	int ret = 0;
 	unsigned long data_ptr;
 
 	path = btrfs_alloc_path();
@@ -44,28 +38,21 @@ ssize_t __btrfs_getxattr(struct inode *inode, const char *name,
 		return -ENOMEM;
 
 	/* lookup the xattr by name */
-	di = btrfs_lookup_xattr(NULL, root, path, btrfs_ino(inode), name,
-				strlen(name), 0);
-	if (!di) {
-		ret = -ENODATA;
-		goto out;
-	} else if (IS_ERR(di)) {
-		ret = PTR_ERR(di);
-		goto out;
-	}
+	di = btrfs_lookup_xattr(NULL, root, path, btrfs_ino(BTRFS_I(inode)),
+			name, strlen(name), 0);
+	if (!di)
+		return -ENODATA;
+	if (IS_ERR(di))
+		return PTR_ERR(di);
 
 	leaf = path->nodes[0];
 	/* if size is 0, that means we want the size of the attr */
-	if (!size) {
-		ret = btrfs_dir_data_len(leaf, di);
-		goto out;
-	}
+	if (!size)
+		return btrfs_dir_data_len(leaf, di);
 
 	/* now get the data out of our dir_item */
-	if (btrfs_dir_data_len(leaf, di) > size) {
-		ret = -ERANGE;
-		goto out;
-	}
+	if (btrfs_dir_data_len(leaf, di) > size)
+		return -ERANGE;
 
 	/*
 	 * The way things are packed into the leaf is like this
@@ -78,358 +65,457 @@ ssize_t __btrfs_getxattr(struct inode *inode, const char *name,
 				   btrfs_dir_name_len(leaf, di));
 	read_extent_buffer(leaf, buffer, data_ptr,
 			   btrfs_dir_data_len(leaf, di));
-	ret = btrfs_dir_data_len(leaf, di);
-
-out:
-	btrfs_free_path(path);
-	return ret;
+	return btrfs_dir_data_len(leaf, di);
 }
 
-static int do_setxattr(struct btrfs_trans_handle *trans,
-		       struct inode *inode, const char *name,
-		       const void *value, size_t size, int flags)
+int btrfs_setxattr(struct btrfs_trans_handle *trans, struct inode *inode,
+		   const char *name, const void *value, size_t size, int flags)
 {
-	struct btrfs_dir_item *di;
+	struct btrfs_dir_item *di = NULL;
 	struct btrfs_root *root = BTRFS_I(inode)->root;
-	struct btrfs_path *path;
+	BTRFS_PATH_AUTO_FREE(path);
 	size_t name_len = strlen(name);
 	int ret = 0;
 
-	if (name_len + size > BTRFS_MAX_XATTR_SIZE(root))
+	ASSERT(trans);
+
+	if (name_len + size > BTRFS_MAX_XATTR_SIZE(root->fs_info))
 		return -ENOSPC;
 
 	path = btrfs_alloc_path();
 	if (!path)
 		return -ENOMEM;
+	path->skip_release_on_error = true;
 
-	if (flags & XATTR_REPLACE) {
-		di = btrfs_lookup_xattr(trans, root, path, btrfs_ino(inode), name,
-					name_len, -1);
-		if (IS_ERR(di)) {
+	if (!value) {
+		di = btrfs_lookup_xattr(trans, root, path,
+				btrfs_ino(BTRFS_I(inode)), name, name_len, -1);
+		if (!di && (flags & XATTR_REPLACE))
+			ret = -ENODATA;
+		else if (IS_ERR(di))
 			ret = PTR_ERR(di);
-			goto out;
-		} else if (!di) {
+		else if (di)
+			ret = btrfs_delete_one_dir_name(trans, root, path, di);
+		goto out;
+	}
+
+	/*
+	 * For a replace we can't just do the insert blindly.
+	 * Do a lookup first (read-only btrfs_search_slot), and return if xattr
+	 * doesn't exist. If it exists, fall down below to the insert/replace
+	 * path - we can't race with a concurrent xattr delete, because the VFS
+	 * locks the inode's i_mutex before calling setxattr or removexattr.
+	 */
+	if (flags & XATTR_REPLACE) {
+		btrfs_assert_inode_locked(BTRFS_I(inode));
+		di = btrfs_lookup_xattr(NULL, root, path,
+				btrfs_ino(BTRFS_I(inode)), name, name_len, 0);
+		if (!di)
 			ret = -ENODATA;
-			goto out;
-		}
-		ret = btrfs_delete_one_dir_name(trans, root, path, di);
+		else if (IS_ERR(di))
+			ret = PTR_ERR(di);
 		if (ret)
 			goto out;
 		btrfs_release_path(path);
+		di = NULL;
+	}
 
+	ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(BTRFS_I(inode)),
+				      name, name_len, value, size);
+	if (ret == -EOVERFLOW) {
 		/*
-		 * remove the attribute
+		 * We have an existing item in a leaf, split_leaf couldn't
+		 * expand it. That item might have or not a dir_item that
+		 * matches our target xattr, so lets check.
 		 */
-		if (!value)
-			goto out;
-	} else {
-		di = btrfs_lookup_xattr(NULL, root, path, btrfs_ino(inode),
-					name, name_len, 0);
-		if (IS_ERR(di)) {
-			ret = PTR_ERR(di);
+		ret = 0;
+		btrfs_assert_tree_write_locked(path->nodes[0]);
+		di = btrfs_match_dir_item_name(path, name, name_len);
+		if (!di && !(flags & XATTR_REPLACE)) {
+			ret = -ENOSPC;
 			goto out;
 		}
-		if (!di && !value)
-			goto out;
-		btrfs_release_path(path);
+	} else if (ret == -EEXIST) {
+		ret = 0;
+		di = btrfs_match_dir_item_name(path, name, name_len);
+		ASSERT(di); /* logic error */
+	} else if (ret) {
+		goto out;
 	}
 
-again:
-	ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(inode),
-				      name, name_len, value, size);
-	/*
-	 * If we're setting an xattr to a new value but the new value is say
-	 * exactly BTRFS_MAX_XATTR_SIZE, we could end up with EOVERFLOW getting
-	 * back from split_leaf.  This is because it thinks we'll be extending
-	 * the existing item size, but we're asking for enough space to add the
-	 * item itself.  So if we get EOVERFLOW just set ret to EEXIST and let
-	 * the rest of the function figure it out.
-	 */
-	if (ret == -EOVERFLOW)
+	if (di && (flags & XATTR_CREATE)) {
 		ret = -EEXIST;
+		goto out;
+	}
 
-	if (ret == -EEXIST) {
-		if (flags & XATTR_CREATE)
-			goto out;
+	if (di) {
 		/*
-		 * We can't use the path we already have since we won't have the
-		 * proper locking for a delete, so release the path and
-		 * re-lookup to delete the thing.
+		 * We're doing a replace, and it must be atomic, that is, at
+		 * any point in time we have either the old or the new xattr
+		 * value in the tree. We don't want readers (getxattr and
+		 * listxattrs) to miss a value, this is specially important
+		 * for ACLs.
 		 */
-		btrfs_release_path(path);
-		di = btrfs_lookup_xattr(trans, root, path, btrfs_ino(inode),
-					name, name_len, -1);
-		if (IS_ERR(di)) {
-			ret = PTR_ERR(di);
-			goto out;
-		} else if (!di) {
-			/* Shouldn't happen but just in case... */
-			btrfs_release_path(path);
-			goto again;
+		const int slot = path->slots[0];
+		struct extent_buffer *leaf = path->nodes[0];
+		const u16 old_data_len = btrfs_dir_data_len(leaf, di);
+		const u32 item_size = btrfs_item_size(leaf, slot);
+		const u32 data_size = sizeof(*di) + name_len + size;
+		unsigned long data_ptr;
+		char *ptr;
+
+		if (size > old_data_len) {
+			if (btrfs_leaf_free_space(leaf) <
+			    (size - old_data_len)) {
+				ret = -ENOSPC;
+				goto out;
+			}
 		}
 
-		ret = btrfs_delete_one_dir_name(trans, root, path, di);
-		if (ret)
-			goto out;
+		if (old_data_len + name_len + sizeof(*di) == item_size) {
+			/* No other xattrs packed in the same leaf item. */
+			if (size > old_data_len)
+				btrfs_extend_item(trans, path, size - old_data_len);
+			else if (size < old_data_len)
+				btrfs_truncate_item(trans, path, data_size, 1);
+		} else {
+			/* There are other xattrs packed in the same item. */
+			ret = btrfs_delete_one_dir_name(trans, root, path, di);
+			if (ret)
+				goto out;
+			btrfs_extend_item(trans, path, data_size);
+		}
 
+		ptr = btrfs_item_ptr(leaf, slot, char);
+		ptr += btrfs_item_size(leaf, slot) - data_size;
+		di = (struct btrfs_dir_item *)ptr;
+		btrfs_set_dir_data_len(leaf, di, size);
+		data_ptr = ((unsigned long)(di + 1)) + name_len;
+		write_extent_buffer(leaf, value, data_ptr, size);
+	} else {
 		/*
-		 * We have a value to set, so go back and try to insert it now.
+		 * Insert, and we had space for the xattr, so path->slots[0] is
+		 * where our xattr dir_item is and btrfs_insert_xattr_item()
+		 * filled it.
 		 */
-		if (value) {
-			btrfs_release_path(path);
-			goto again;
-		}
 	}
 out:
-	btrfs_free_path(path);
+	if (!ret) {
+		set_bit(BTRFS_INODE_COPY_EVERYTHING,
+			&BTRFS_I(inode)->runtime_flags);
+		clear_bit(BTRFS_INODE_NO_XATTRS, &BTRFS_I(inode)->runtime_flags);
+	}
 	return ret;
 }
 
 /*
  * @value: "" makes the attribute to empty, NULL removes it
  */
-int __btrfs_setxattr(struct btrfs_trans_handle *trans,
-		     struct inode *inode, const char *name,
-		     const void *value, size_t size, int flags)
+int btrfs_setxattr_trans(struct inode *inode, const char *name,
+			 const void *value, size_t size, int flags)
 {
 	struct btrfs_root *root = BTRFS_I(inode)->root;
+	struct btrfs_trans_handle *trans;
+	const bool start_trans = (current->journal_info == NULL);
 	int ret;
 
-	if (trans)
-		return do_setxattr(trans, inode, name, value, size, flags);
-
-	trans = btrfs_start_transaction(root, 2);
-	if (IS_ERR(trans))
-		return PTR_ERR(trans);
+	if (start_trans) {
+		/*
+		 * 1 unit for inserting/updating/deleting the xattr
+		 * 1 unit for the inode item update
+		 */
+		trans = btrfs_start_transaction(root, 2);
+		if (IS_ERR(trans))
+			return PTR_ERR(trans);
+	} else {
+		/*
+		 * This can happen when smack is enabled and a directory is being
+		 * created. It happens through d_instantiate_new(), which calls
+		 * smack_d_instantiate(), which in turn calls __vfs_setxattr() to
+		 * set the transmute xattr (XATTR_NAME_SMACKTRANSMUTE) on the
+		 * inode. We have already reserved space for the xattr and inode
+		 * update at btrfs_mkdir(), so just use the transaction handle.
+		 * We don't join or start a transaction, as that will reset the
+		 * block_rsv of the handle and trigger a warning for the start
+		 * case.
+		 */
+		ASSERT(strncmp(name, XATTR_SECURITY_PREFIX,
+			       XATTR_SECURITY_PREFIX_LEN) == 0);
+		trans = current->journal_info;
+	}
 
-	ret = do_setxattr(trans, inode, name, value, size, flags);
+	ret = btrfs_setxattr(trans, inode, name, value, size, flags);
 	if (ret)
 		goto out;
 
 	inode_inc_iversion(inode);
-	inode->i_ctime = CURRENT_TIME;
-	set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags);
-	ret = btrfs_update_inode(trans, root, inode);
-	BUG_ON(ret);
+	inode_set_ctime_current(inode);
+	ret = btrfs_update_inode(trans, BTRFS_I(inode));
+	if (ret)
+		btrfs_abort_transaction(trans, ret);
 out:
-	btrfs_end_transaction(trans, root);
+	if (start_trans)
+		btrfs_end_transaction(trans);
 	return ret;
 }
 
 ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
 {
-	struct btrfs_key key, found_key;
-	struct inode *inode = dentry->d_inode;
+	struct btrfs_key found_key;
+	struct btrfs_key key;
+	struct inode *inode = d_inode(dentry);
 	struct btrfs_root *root = BTRFS_I(inode)->root;
-	struct btrfs_path *path;
-	struct extent_buffer *leaf;
-	struct btrfs_dir_item *di;
-	int ret = 0, slot;
+	BTRFS_PATH_AUTO_FREE(path);
+	int iter_ret = 0;
+	int ret = 0;
 	size_t total_size = 0, size_left = size;
-	unsigned long name_ptr;
-	size_t name_len;
 
 	/*
 	 * ok we want all objects associated with this id.
 	 * NOTE: we set key.offset = 0; because we want to start with the
 	 * first xattr that we find and walk forward
 	 */
-	key.objectid = btrfs_ino(inode);
-	btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
+	key.objectid = btrfs_ino(BTRFS_I(inode));
+	key.type = BTRFS_XATTR_ITEM_KEY;
 	key.offset = 0;
 
 	path = btrfs_alloc_path();
 	if (!path)
 		return -ENOMEM;
-	path->reada = 2;
+	path->reada = READA_FORWARD;
 
 	/* search for our xattrs */
-	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
-	if (ret < 0)
-		goto err;
+	btrfs_for_each_slot(root, &key, &found_key, path, iter_ret) {
+		struct extent_buffer *leaf;
+		int slot;
+		struct btrfs_dir_item *di;
+		u32 item_size;
+		u32 cur;
 
-	while (1) {
 		leaf = path->nodes[0];
 		slot = path->slots[0];
 
-		/* this is where we start walking through the path */
-		if (slot >= btrfs_header_nritems(leaf)) {
-			/*
-			 * if we've reached the last slot in this leaf we need
-			 * to go to the next leaf and reset everything
-			 */
-			ret = btrfs_next_leaf(root, path);
-			if (ret < 0)
-				goto err;
-			else if (ret > 0)
-				break;
-			continue;
-		}
-
-		btrfs_item_key_to_cpu(leaf, &found_key, slot);
-
 		/* check to make sure this item is what we want */
 		if (found_key.objectid != key.objectid)
 			break;
-		if (btrfs_key_type(&found_key) != BTRFS_XATTR_ITEM_KEY)
+		if (found_key.type > BTRFS_XATTR_ITEM_KEY)
 			break;
+		if (found_key.type < BTRFS_XATTR_ITEM_KEY)
+			continue;
 
 		di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
-		if (verify_dir_item(root, leaf, di))
-			goto next;
-
-		name_len = btrfs_dir_name_len(leaf, di);
-		total_size += name_len + 1;
-
-		/* we are just looking for how big our buffer needs to be */
-		if (!size)
-			goto next;
+		item_size = btrfs_item_size(leaf, slot);
+		cur = 0;
+		while (cur < item_size) {
+			u16 name_len = btrfs_dir_name_len(leaf, di);
+			u16 data_len = btrfs_dir_data_len(leaf, di);
+			u32 this_len = sizeof(*di) + name_len + data_len;
+			unsigned long name_ptr = (unsigned long)(di + 1);
+
+			total_size += name_len + 1;
+			/*
+			 * We are just looking for how big our buffer needs to
+			 * be.
+			 */
+			if (!size)
+				goto next;
 
-		if (!buffer || (name_len + 1) > size_left) {
-			ret = -ERANGE;
-			goto err;
-		}
+			if (!buffer || (name_len + 1) > size_left) {
+			        iter_ret = -ERANGE;
+				break;
+			}
 
-		name_ptr = (unsigned long)(di + 1);
-		read_extent_buffer(leaf, buffer, name_ptr, name_len);
-		buffer[name_len] = '\0';
+			read_extent_buffer(leaf, buffer, name_ptr, name_len);
+			buffer[name_len] = '\0';
 
-		size_left -= name_len + 1;
-		buffer += name_len + 1;
+			size_left -= name_len + 1;
+			buffer += name_len + 1;
 next:
-		path->slots[0]++;
+			cur += this_len;
+			di = (struct btrfs_dir_item *)((char *)di + this_len);
+		}
 	}
-	ret = total_size;
 
-err:
-	btrfs_free_path(path);
+	if (iter_ret < 0)
+		ret = iter_ret;
+	else
+		ret = total_size;
 
 	return ret;
 }
 
-/*
- * List of handlers for synthetic system.* attributes.  All real ondisk
- * attributes are handled directly.
- */
-const struct xattr_handler *btrfs_xattr_handlers[] = {
-#ifdef CONFIG_BTRFS_FS_POSIX_ACL
-	&btrfs_xattr_acl_access_handler,
-	&btrfs_xattr_acl_default_handler,
-#endif
-	NULL,
-};
-
-/*
- * Check if the attribute is in a supported namespace.
- *
- * This applied after the check for the synthetic attributes in the system
- * namespace.
- */
-static bool btrfs_is_valid_xattr(const char *name)
+static int btrfs_xattr_handler_get(const struct xattr_handler *handler,
+				   struct dentry *unused, struct inode *inode,
+				   const char *name, void *buffer, size_t size)
 {
-	return !strncmp(name, XATTR_SECURITY_PREFIX,
-			XATTR_SECURITY_PREFIX_LEN) ||
-	       !strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) ||
-	       !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) ||
-	       !strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN);
+	name = xattr_full_name(handler, name);
+	return btrfs_getxattr(inode, name, buffer, size);
 }
 
-ssize_t btrfs_getxattr(struct dentry *dentry, const char *name,
-		       void *buffer, size_t size)
+static int btrfs_xattr_handler_set(const struct xattr_handler *handler,
+				   struct mnt_idmap *idmap,
+				   struct dentry *unused, struct inode *inode,
+				   const char *name, const void *buffer,
+				   size_t size, int flags)
 {
-	/*
-	 * 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);
+	if (btrfs_root_readonly(BTRFS_I(inode)->root))
+		return -EROFS;
 
-	if (!btrfs_is_valid_xattr(name))
-		return -EOPNOTSUPP;
-	return __btrfs_getxattr(dentry->d_inode, name, buffer, size);
+	name = xattr_full_name(handler, name);
+	return btrfs_setxattr_trans(inode, name, buffer, size, flags);
 }
 
-int btrfs_setxattr(struct dentry *dentry, const char *name, const void *value,
-		   size_t size, int flags)
+static int btrfs_xattr_handler_get_security(const struct xattr_handler *handler,
+					    struct dentry *unused,
+					    struct inode *inode,
+					    const char *name, void *buffer,
+					    size_t size)
 {
-	struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root;
+	int ret;
+	bool is_cap = false;
 
-	/*
-	 * The permission on security.* and system.* is not checked
-	 * in permission().
-	 */
-	if (btrfs_root_readonly(root))
-		return -EROFS;
+	name = xattr_full_name(handler, name);
 
 	/*
-	 * 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.
+	 * security.capability doesn't cache the results, so calls into us
+	 * constantly to see if there's a capability xattr.  Cache the result
+	 * here in order to avoid wasting time doing lookups for xattrs we know
+	 * don't exist.
 	 */
-	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
-		return generic_setxattr(dentry, name, value, size, flags);
+	if (strcmp(name, XATTR_NAME_CAPS) == 0) {
+		is_cap = true;
+		if (test_bit(BTRFS_INODE_NO_CAP_XATTR, &BTRFS_I(inode)->runtime_flags))
+			return -ENODATA;
+	}
+
+	ret = btrfs_getxattr(inode, name, buffer, size);
+	if (ret == -ENODATA && is_cap)
+		set_bit(BTRFS_INODE_NO_CAP_XATTR, &BTRFS_I(inode)->runtime_flags);
+	return ret;
+}
 
-	if (!btrfs_is_valid_xattr(name))
-		return -EOPNOTSUPP;
+static int btrfs_xattr_handler_set_security(const struct xattr_handler *handler,
+					    struct mnt_idmap *idmap,
+					    struct dentry *unused,
+					    struct inode *inode,
+					    const char *name,
+					    const void *buffer,
+					    size_t size, int flags)
+{
+	if (btrfs_root_readonly(BTRFS_I(inode)->root))
+		return -EROFS;
 
-	if (size == 0)
-		value = "";  /* empty EA, do not remove */
+	name = xattr_full_name(handler, name);
+	if (strcmp(name, XATTR_NAME_CAPS) == 0)
+		clear_bit(BTRFS_INODE_NO_CAP_XATTR, &BTRFS_I(inode)->runtime_flags);
 
-	return __btrfs_setxattr(NULL, dentry->d_inode, name, value, size,
-				flags);
+	return btrfs_setxattr_trans(inode, name, buffer, size, flags);
 }
 
-int btrfs_removexattr(struct dentry *dentry, const char *name)
+static int btrfs_xattr_handler_set_prop(const struct xattr_handler *handler,
+					struct mnt_idmap *idmap,
+					struct dentry *unused, struct inode *inode,
+					const char *name, const void *value,
+					size_t size, int flags)
 {
-	struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root;
+	int ret;
+	struct btrfs_trans_handle *trans;
+	struct btrfs_root *root = BTRFS_I(inode)->root;
 
-	/*
-	 * The permission on security.* and system.* is not checked
-	 * in permission().
-	 */
-	if (btrfs_root_readonly(root))
-		return -EROFS;
+	name = xattr_full_name(handler, name);
+	ret = btrfs_validate_prop(BTRFS_I(inode), name, value, size);
+	if (ret)
+		return ret;
 
-	/*
-	 * 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);
+	if (btrfs_ignore_prop(BTRFS_I(inode), name))
+		return 0;
 
-	if (!btrfs_is_valid_xattr(name))
-		return -EOPNOTSUPP;
+	trans = btrfs_start_transaction(root, 2);
+	if (IS_ERR(trans))
+		return PTR_ERR(trans);
+
+	ret = btrfs_set_prop(trans, BTRFS_I(inode), name, value, size, flags);
+	if (!ret) {
+		inode_inc_iversion(inode);
+		inode_set_ctime_current(inode);
+		ret = btrfs_update_inode(trans, BTRFS_I(inode));
+		if (ret)
+			btrfs_abort_transaction(trans, ret);
+	}
 
-	return __btrfs_setxattr(NULL, dentry->d_inode, name, NULL, 0,
-				XATTR_REPLACE);
+	btrfs_end_transaction(trans);
+
+	return ret;
 }
 
+static const struct xattr_handler btrfs_security_xattr_handler = {
+	.prefix = XATTR_SECURITY_PREFIX,
+	.get = btrfs_xattr_handler_get_security,
+	.set = btrfs_xattr_handler_set_security,
+};
+
+static const struct xattr_handler btrfs_trusted_xattr_handler = {
+	.prefix = XATTR_TRUSTED_PREFIX,
+	.get = btrfs_xattr_handler_get,
+	.set = btrfs_xattr_handler_set,
+};
+
+static const struct xattr_handler btrfs_user_xattr_handler = {
+	.prefix = XATTR_USER_PREFIX,
+	.get = btrfs_xattr_handler_get,
+	.set = btrfs_xattr_handler_set,
+};
+
+static const struct xattr_handler btrfs_btrfs_xattr_handler = {
+	.prefix = XATTR_BTRFS_PREFIX,
+	.get = btrfs_xattr_handler_get,
+	.set = btrfs_xattr_handler_set_prop,
+};
+
+const struct xattr_handler * const btrfs_xattr_handlers[] = {
+	&btrfs_security_xattr_handler,
+	&btrfs_trusted_xattr_handler,
+	&btrfs_user_xattr_handler,
+	&btrfs_btrfs_xattr_handler,
+	NULL,
+};
+
 static int btrfs_initxattrs(struct inode *inode,
-			    const struct xattr *xattr_array, void *fs_info)
+			    const struct xattr *xattr_array, void *fs_private)
 {
+	struct btrfs_trans_handle *trans = fs_private;
 	const struct xattr *xattr;
-	struct btrfs_trans_handle *trans = fs_info;
+	unsigned int nofs_flag;
 	char *name;
-	int err = 0;
+	int ret = 0;
 
+	/*
+	 * We're holding a transaction handle, so use a NOFS memory allocation
+	 * context to avoid deadlock if reclaim happens.
+	 */
+	nofs_flag = memalloc_nofs_save();
 	for (xattr = xattr_array; xattr->name != NULL; xattr++) {
-		name = kmalloc(XATTR_SECURITY_PREFIX_LEN +
-			       strlen(xattr->name) + 1, GFP_NOFS);
+		const size_t name_len = XATTR_SECURITY_PREFIX_LEN +
+					strlen(xattr->name) + 1;
+
+		name = kmalloc(name_len, GFP_KERNEL);
 		if (!name) {
-			err = -ENOMEM;
+			ret = -ENOMEM;
 			break;
 		}
-		strcpy(name, XATTR_SECURITY_PREFIX);
-		strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name);
-		err = __btrfs_setxattr(trans, inode, name,
-				       xattr->value, xattr->value_len, 0);
+		scnprintf(name, name_len, "%s%s", XATTR_SECURITY_PREFIX, xattr->name);
+
+		if (strcmp(name, XATTR_NAME_CAPS) == 0)
+			clear_bit(BTRFS_INODE_NO_CAP_XATTR, &BTRFS_I(inode)->runtime_flags);
+
+		ret = btrfs_setxattr(trans, inode, name, xattr->value,
+				     xattr->value_len, 0);
 		kfree(name);
-		if (err < 0)
+		if (ret < 0)
 			break;
 	}
-	return err;
+	memalloc_nofs_restore(nofs_flag);
+	return ret;
 }
 
 int btrfs_xattr_security_init(struct btrfs_trans_handle *trans,