@@ -9,7 +9,7 @@ btrfs-y += super.o ctree.o extent-tree.o print-tree.o root-tree.o dir-item.o \
export.o tree-log.o free-space-cache.o zlib.o lzo.o \
compression.o delayed-ref.o relocation.o delayed-inode.o scrub.o \
reada.o backref.o ulist.o qgroup.o send.o dev-replace.o raid56.o \
- uuid-tree.o
+ uuid-tree.o props.o
btrfs-$(CONFIG_BTRFS_FS_POSIX_ACL) += acl.o
btrfs-$(CONFIG_BTRFS_FS_CHECK_INTEGRITY) += check-integrity.o
@@ -43,6 +43,7 @@
#define BTRFS_INODE_COPY_EVERYTHING 8
#define BTRFS_INODE_IN_DELALLOC_LIST 9
#define BTRFS_INODE_READDIO_NEED_LOCK 10
+#define BTRFS_INODE_HAS_PROPS 11
/* in memory btrfs inode */
struct btrfs_inode {
@@ -58,6 +58,7 @@
#include "inode-map.h"
#include "backref.h"
#include "hash.h"
+#include "props.h"
struct btrfs_iget_args {
u64 ino;
@@ -3247,7 +3248,8 @@ out:
* slot is the slot the inode is in, objectid is the objectid of the inode
*/
static noinline int acls_after_inode_item(struct extent_buffer *leaf,
- int slot, u64 objectid)
+ int slot, u64 objectid,
+ int *has_xattrs)
{
u32 nritems = btrfs_header_nritems(leaf);
struct btrfs_key found_key;
@@ -3272,6 +3274,7 @@ static noinline int acls_after_inode_item(struct extent_buffer *leaf,
/* we found an xattr, assume we've got an acl */
if (found_key.type == BTRFS_XATTR_ITEM_KEY) {
+ *has_xattrs = 1;
if (found_key.offset == xattr_access ||
found_key.offset == xattr_default)
return 1;
@@ -3300,13 +3303,15 @@ static noinline int acls_after_inode_item(struct extent_buffer *leaf,
* something larger than an xattr. We have to assume the inode
* has acls
*/
+ *has_xattrs = 1;
+
return 1;
}
/*
* read an inode from the btree into the in-memory inode
*/
-static void btrfs_read_locked_inode(struct inode *inode)
+static void btrfs_read_locked_inode(struct inode *inode, int *has_xattrs)
{
struct btrfs_path *path;
struct extent_buffer *leaf;
@@ -3386,7 +3391,7 @@ cache_acl:
* any xattrs or acls
*/
maybe_acls = acls_after_inode_item(leaf, path->slots[0],
- btrfs_ino(inode));
+ btrfs_ino(inode), has_xattrs);
if (!maybe_acls)
cache_no_acl(inode);
@@ -4871,6 +4876,8 @@ struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
struct btrfs_root *root, int *new)
{
struct inode *inode;
+ int has_xattrs = 0;
+ int ret;
inode = btrfs_iget_locked(s, location->objectid, root);
if (!inode)
@@ -4879,10 +4886,17 @@ struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
if (inode->i_state & I_NEW) {
BTRFS_I(inode)->root = root;
memcpy(&BTRFS_I(inode)->location, location, sizeof(*location));
- btrfs_read_locked_inode(inode);
+ btrfs_read_locked_inode(inode, &has_xattrs);
if (!is_bad_inode(inode)) {
inode_tree_add(inode);
unlock_new_inode(inode);
+ if (has_xattrs) {
+ ret = btrfs_load_inode_props(inode);
+ if (ret)
+ pr_err("btrfs: error loading props for ino %llu (root %llu): %d\n",
+ btrfs_ino(inode),
+ root->root_key.objectid, ret);
+ }
if (new)
*new = 1;
} else {
@@ -5486,6 +5500,11 @@ static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
btrfs_update_root_times(trans, root);
+ ret = btrfs_inherit_props(trans, inode, dir);
+ if (ret)
+ pr_err("btrfs: error inheriting props for ino %llu (root %llu): %d",
+ btrfs_ino(inode), root->root_key.objectid, ret);
+
return inode;
fail:
if (dir)
@@ -53,6 +53,7 @@
#include "locking.h"
#include "inode-map.h"
#include "backref.h"
+#include "props.h"
#include "rcu-string.h"
#include "send.h"
#include "dev-replace.h"
@@ -4474,6 +4475,132 @@ out_unlock:
return ret;
}
+static int btrfs_ioctl_get_prop(struct file *file, void __user *arg)
+{
+ struct inode *inode = file_inode(file);
+ struct btrfs_ioctl_getset_prop_args *get_args = NULL;
+ int ret;
+ char *name = NULL;
+ char *value = NULL;
+ size_t value_len = 0;
+ size_t off = offsetof(struct btrfs_ioctl_getset_prop_args, value_len);
+
+ ret = inode_permission(inode, MAY_READ);
+ if (ret)
+ return ret;
+
+ get_args = memdup_user(arg, sizeof(*get_args));
+ if (IS_ERR(get_args)) {
+ ret = PTR_ERR(get_args);
+ get_args = NULL;
+ goto out;
+ }
+
+ name = kmalloc(get_args->name_len + 1, GFP_NOFS);
+ if (!name) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ if (copy_from_user(name, (char __user *) get_args->name_ptr,
+ get_args->name_len)) {
+ ret = -EFAULT;
+ goto out;
+ }
+ name[get_args->name_len] = '\0';
+
+ if (get_args->value_len == 0) {
+ ret = btrfs_get_prop(inode, name, NULL, &value_len);
+ if (!ret) {
+ ASSERT(value_len <= (u16)-1);
+ if (copy_to_user(arg + off, &value_len,
+ sizeof(get_args->value_len)))
+ ret = -EFAULT;
+ }
+ goto out;
+ }
+
+ value_len = get_args->value_len;
+ value = kmalloc(value_len, GFP_NOFS);
+ if (!value) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ ret = btrfs_get_prop(inode, name, value, &value_len);
+ if (ret)
+ goto out;
+
+ if (copy_to_user((void __user *) get_args->value_ptr,
+ value, value_len)) {
+ ret = -EFAULT;
+ goto out;
+ }
+ if (copy_to_user(arg + off, &value_len, sizeof(get_args->value_len)))
+ ret = -EFAULT;
+out:
+ kfree(value);
+ kfree(name);
+ kfree(get_args);
+
+ return ret;
+}
+
+static int btrfs_ioctl_set_prop(struct file *file, void __user *arg)
+{
+ struct inode *inode = file_inode(file);
+ struct btrfs_root *root = BTRFS_I(inode)->root;
+ struct btrfs_ioctl_getset_prop_args *set_args = NULL;
+ char *name = NULL;
+ char *value = NULL;
+ int ret;
+
+ ret = inode_permission(inode, MAY_WRITE);
+ if (ret)
+ return ret;
+
+ set_args = memdup_user(arg, sizeof(*set_args));
+ if (IS_ERR(set_args)) {
+ ret = PTR_ERR(set_args);
+ set_args = NULL;
+ goto out;
+ }
+
+ if (set_args->name_len + set_args->value_len >
+ BTRFS_MAX_XATTR_SIZE(root)) {
+ ret = -ENOSPC;
+ goto out;
+ }
+
+ name = kmalloc(set_args->name_len + 1, GFP_NOFS);
+ if (!name) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ if (copy_from_user(name, (char __user *) set_args->name_ptr,
+ set_args->name_len)) {
+ ret = -EFAULT;
+ goto out;
+ }
+ name[set_args->name_len] = '\0';
+
+ value = memdup_user((char __user *) set_args->value_ptr,
+ set_args->value_len);
+ if (IS_ERR(value)) {
+ ret = PTR_ERR(value);
+ value = NULL;
+ goto out;
+ }
+
+ ret = btrfs_set_prop(inode, name, value, set_args->value_len);
+out:
+ kfree(value);
+ kfree(name);
+ kfree(set_args);
+
+ return ret;
+}
+
long btrfs_ioctl(struct file *file, unsigned int
cmd, unsigned long arg)
{
@@ -4539,6 +4666,10 @@ long btrfs_ioctl(struct file *file, unsigned int
return btrfs_ioctl_logical_to_ino(root, argp);
case BTRFS_IOC_SPACE_INFO:
return btrfs_ioctl_space_info(root, argp);
+ case BTRFS_IOC_GET_PROP:
+ return btrfs_ioctl_get_prop(file, argp);
+ case BTRFS_IOC_SET_PROP:
+ return btrfs_ioctl_set_prop(file, argp);
case BTRFS_IOC_SYNC: {
int ret;
new file mode 100644
@@ -0,0 +1,389 @@
+/*
+ * Copyright (C) 2013 Filipe David Borba Manana <fdmanana@gmail.com>
+ *
+ * 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 "props.h"
+#include "btrfs_inode.h"
+#include "transaction.h"
+#include "xattr.h"
+
+struct prop_handler {
+ const char *xattr_name;
+ int (*validate)(const char *value, size_t len);
+ int (*apply)(struct inode *inode, const char *value, size_t len);
+ int inheritable;
+};
+
+static int prop_compression_validate(const char *value, size_t len);
+
+static int prop_compression_apply(struct inode *inode,
+ const char *value,
+ size_t len);
+
+static const struct prop_handler prop_handlers[] = {
+ {
+ .xattr_name = "btrfs.compression",
+ .validate = prop_compression_validate,
+ .apply = prop_compression_apply,
+ .inheritable = 1
+ },
+ {
+ .xattr_name = NULL,
+ .validate = NULL,
+ .apply = NULL
+ }
+};
+
+
+static const struct prop_handler *find_prop_handler(const char *name)
+{
+ const struct prop_handler *p;
+
+ for (p = &prop_handlers[0]; p->xattr_name; p++)
+ if (!strcmp(p->xattr_name + 6, name))
+ return p;
+ return NULL;
+}
+
+static int __btrfs_set_prop(struct btrfs_trans_handle *trans,
+ struct inode *inode,
+ const char *name,
+ const char *value,
+ size_t value_len)
+{
+ const struct prop_handler *handler;
+ int ret;
+
+ handler = find_prop_handler(name);
+ if (!handler)
+ return -EINVAL;
+
+ if (value_len == 0) {
+ ret = __btrfs_setxattr(trans, inode, handler->xattr_name,
+ NULL, 0, XATTR_REPLACE);
+ if (ret)
+ return ret;
+
+ mutex_lock(&inode->i_mutex);
+ ret = handler->apply(inode, NULL, 0);
+ mutex_unlock(&inode->i_mutex);
+ ASSERT(ret == 0);
+
+ return ret;
+ }
+
+ ret = handler->validate(value, value_len);
+ if (ret)
+ return ret;
+
+ ret = __btrfs_setxattr(trans, inode, handler->xattr_name,
+ value, value_len, XATTR_CREATE);
+ if (ret == -EEXIST)
+ ret = __btrfs_setxattr(trans, inode, handler->xattr_name,
+ value, value_len, XATTR_REPLACE);
+
+ if (ret)
+ return ret;
+
+ mutex_lock(&inode->i_mutex);
+ ret = handler->apply(inode, value, value_len);
+ mutex_unlock(&inode->i_mutex);
+
+ if (!ret)
+ set_bit(BTRFS_INODE_HAS_PROPS, &BTRFS_I(inode)->runtime_flags);
+
+ return ret;
+}
+
+int btrfs_set_prop(struct inode *inode,
+ const char *name,
+ const char *value,
+ size_t value_len)
+{
+ return __btrfs_set_prop(NULL, inode, name, value, value_len);
+}
+
+
+/*
+ * Return -ENODATA if property is not set.
+ * Return -ERANGE if input buffer isn't big enough to hold property value.
+ */
+int btrfs_get_prop(struct inode *inode,
+ const char *name,
+ char *buf,
+ size_t *len)
+{
+ const struct prop_handler *handler;
+ ssize_t ret;
+
+ handler = find_prop_handler(name);
+ if (!handler)
+ return -EINVAL;
+
+ if (*len == 0) {
+ ret = __btrfs_getxattr(inode, handler->xattr_name, NULL, 0);
+ if (ret < 0)
+ return ret;
+ *len = (size_t) ret;
+ return 0;
+ }
+
+ ret = __btrfs_getxattr(inode, handler->xattr_name, buf, *len);
+ if (ret < 0)
+ return ret;
+
+ *len = (size_t) ret;
+
+ return 0;
+}
+
+int btrfs_load_inode_props(struct inode *inode)
+{
+ struct btrfs_root *root = BTRFS_I(inode)->root;
+ struct btrfs_key key;
+ struct btrfs_path *path;
+ u64 ino = btrfs_ino(inode);
+ char *name_buf = NULL;
+ char *value_buf = NULL;
+ int name_buf_len = 0;
+ int value_buf_len = 0;
+ int ret;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ key.objectid = ino;
+ key.type = BTRFS_XATTR_ITEM_KEY;
+ key.offset = 0;
+
+ ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+ if (ret < 0)
+ goto out;
+
+ while (1) {
+ struct btrfs_dir_item *di;
+ struct extent_buffer *leaf;
+ u32 total_len, cur, this_len;
+ int slot;
+
+ slot = path->slots[0];
+ leaf = path->nodes[0];
+
+ if (slot >= btrfs_header_nritems(leaf)) {
+ ret = btrfs_next_leaf(root, path);
+ if (ret < 0)
+ goto out;
+ else if (ret > 0)
+ break;
+ continue;
+ }
+
+ btrfs_item_key_to_cpu(leaf, &key, slot);
+ if (key.objectid != ino || key.type != BTRFS_XATTR_ITEM_KEY)
+ break;
+
+ di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
+ cur = 0;
+ total_len = btrfs_item_size_nr(leaf, slot);
+
+ while (cur < total_len) {
+ u32 name_len = btrfs_dir_name_len(leaf, di);
+ u32 data_len = btrfs_dir_data_len(leaf, di);
+ unsigned long name_ptr, data_ptr;
+ const struct prop_handler *handler;
+
+ this_len = sizeof(*di) + name_len + data_len;
+ name_ptr = (unsigned long)(di + 1);
+ data_ptr = name_ptr + name_len;
+
+ if (name_len <= 6 ||
+ memcmp_extent_buffer(leaf, "btrfs.", name_ptr, 6))
+ goto next;
+
+ if (name_len >= name_buf_len) {
+ kfree(name_buf);
+ name_buf_len = name_len + 1;
+ name_buf = kmalloc(name_buf_len, GFP_NOFS);
+ if (!name_buf) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ }
+ read_extent_buffer(leaf, name_buf, name_ptr, name_len);
+ name_buf[name_len] = '\0';
+
+ if (data_len > value_buf_len) {
+ kfree(value_buf);
+ value_buf_len = data_len;
+ value_buf = kmalloc(data_len, GFP_NOFS);
+ if (!value_buf) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ }
+ read_extent_buffer(leaf, value_buf, data_ptr, data_len);
+
+ handler = find_prop_handler(name_buf + 6);
+ if (!handler) {
+ pr_warn("btrfs: handler for prop %s, ino %llu (root %llu), not found",
+ name_buf, ino, root->root_key.objectid);
+ goto next;
+ }
+
+ ret = handler->apply(inode, value_buf, data_len);
+ if (ret)
+ pr_warn("btrfs: error applying prop %s to ino %llu (root %llu): %d",
+ name_buf, ino,
+ root->root_key.objectid, ret);
+ else
+ set_bit(BTRFS_INODE_HAS_PROPS,
+ &BTRFS_I(inode)->runtime_flags);
+next:
+ cur += this_len;
+ di = (struct btrfs_dir_item *)((char *) di + this_len);
+ }
+
+ path->slots[0]++;
+ }
+
+ ret = 0;
+out:
+ btrfs_free_path(path);
+ kfree(name_buf);
+ kfree(value_buf);
+
+ return ret;
+}
+
+int btrfs_inherit_props(struct btrfs_trans_handle *trans,
+ struct inode *inode,
+ struct inode *dir)
+{
+ const struct prop_handler *h;
+ struct btrfs_root *root = BTRFS_I(inode)->root;
+ char *buf = NULL;
+ int buf_len = 0;
+ struct btrfs_block_rsv *rsv = NULL;
+ struct btrfs_block_rsv *trans_rsv = trans->block_rsv;
+ int ret;
+
+ if (!dir)
+ return 0;
+
+ if (!test_bit(BTRFS_INODE_HAS_PROPS,
+ &BTRFS_I(dir)->runtime_flags))
+ return 0;
+
+ for (h = &prop_handlers[0]; h->xattr_name; h++) {
+ size_t len = 0;
+ const char *name = h->xattr_name + 6;
+ u64 num_bytes;
+
+ if (!h->inheritable)
+ continue;
+again:
+ ret = btrfs_get_prop(dir, name, NULL, &len);
+ if (ret == -ENODATA)
+ continue;
+ else if (ret < 0)
+ goto out;
+
+ if (len > buf_len) {
+ kfree(buf);
+ buf = kmalloc(len, GFP_NOFS);
+ if (!buf) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ buf_len = len;
+ }
+
+ ret = btrfs_get_prop(dir, name, buf, &len);
+ if (ret == -ERANGE)
+ goto again;
+ else if (ret == -ENODATA)
+ continue;
+ else if (ret < 0)
+ goto out;
+
+ if (!rsv) {
+ rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
+ if (!rsv) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ trans->block_rsv = rsv;
+ }
+
+ num_bytes = btrfs_calc_trans_metadata_size(root, 2);
+ ret = btrfs_block_rsv_add(root, trans->block_rsv,
+ num_bytes, BTRFS_RESERVE_NO_FLUSH);
+ if (ret)
+ goto out;
+ ret = __btrfs_set_prop(trans, inode, name, buf, len);
+ if (ret)
+ goto out;
+ }
+ ret = 0;
+out:
+ kfree(buf);
+ if (rsv) {
+ btrfs_free_block_rsv(root, rsv);
+ trans->block_rsv = trans_rsv;
+ }
+
+ return ret;
+}
+
+static int prop_compression_validate(const char *value, size_t len)
+{
+ if (!strncmp("lzo", value, len))
+ return 0;
+ else if (!strncmp("zlib", value, len))
+ return 0;
+
+ return -EINVAL;
+}
+
+static int prop_compression_apply(struct inode *inode,
+ const char *value,
+ size_t len)
+{
+ int type;
+
+ if (len == 0) {
+ BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
+ BTRFS_I(inode)->flags &= ~BTRFS_INODE_COMPRESS;
+ BTRFS_I(inode)->force_compress = BTRFS_COMPRESS_NONE;
+
+ return 0;
+ }
+
+ if (!strncmp("lzo", value, len))
+ type = BTRFS_COMPRESS_LZO;
+ else if (!strncmp("zlib", value, len))
+ type = BTRFS_COMPRESS_ZLIB;
+ else
+ return -EINVAL;
+
+ BTRFS_I(inode)->flags &= ~BTRFS_INODE_NOCOMPRESS;
+ BTRFS_I(inode)->flags |= BTRFS_INODE_COMPRESS;
+ BTRFS_I(inode)->force_compress = type;
+
+ return 0;
+}
new file mode 100644
@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) 2013 Filipe David Borba Manana <fdmanana@gmail.com>
+ *
+ * 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.
+ */
+
+#ifndef __BTRFS_PROPS_H
+#define __BTRFS_PROPS_H
+
+#include "ctree.h"
+
+int btrfs_set_prop(struct inode *inode,
+ const char *name,
+ const char *value,
+ size_t value_len);
+
+int btrfs_get_prop(struct inode *inode,
+ const char *name,
+ char *buf,
+ size_t *len);
+
+int btrfs_load_inode_props(struct inode *inode);
+
+int btrfs_inherit_props(struct btrfs_trans_handle *trans,
+ struct inode *inode,
+ struct inode *dir);
+
+#endif
@@ -472,6 +472,14 @@ struct btrfs_ioctl_send_args {
__u64 reserved[4]; /* in */
};
+struct btrfs_ioctl_getset_prop_args {
+ __u16 name_len; /* in */
+ __u16 value_len; /* in/out */
+ __u8 unused[4];
+ __u64 name_ptr; /* in */
+ __u64 value_ptr; /* in/out */
+};
+
/* Error codes as returned by the kernel */
enum btrfs_err_code {
notused,
@@ -552,6 +560,10 @@ static inline char *btrfs_err_str(enum btrfs_err_code err_code)
#define BTRFS_IOC_DEFAULT_SUBVOL _IOW(BTRFS_IOCTL_MAGIC, 19, __u64)
#define BTRFS_IOC_SPACE_INFO _IOWR(BTRFS_IOCTL_MAGIC, 20, \
struct btrfs_ioctl_space_args)
+#define BTRFS_IOC_GET_PROP _IOR(BTRFS_IOCTL_MAGIC, 21, \
+ struct btrfs_ioctl_getset_prop_args)
+#define BTRFS_IOC_SET_PROP _IOW(BTRFS_IOCTL_MAGIC, 21, \
+ struct btrfs_ioctl_getset_prop_args)
#define BTRFS_IOC_START_SYNC _IOR(BTRFS_IOCTL_MAGIC, 24, __u64)
#define BTRFS_IOC_WAIT_SYNC _IOW(BTRFS_IOCTL_MAGIC, 22, __u64)
#define BTRFS_IOC_SNAP_CREATE_V2 _IOW(BTRFS_IOCTL_MAGIC, 23, \
This change adds infrastructure to allow for generic properties for inodes via a new ioctl. Properties are name/value pairs that can be associated with inodes for different purposes. They're stored as xattrs with the prefix "btrfs." Properties can be inherited - this means when a directory inode has inheritable properties set, these are added to new inodes created under that directory. This change also adds one specific property implementation, named "compression", whose values can be "lzo" or "zlib" and it's an inheritable property. The corresponding changes to btrfs-progs were also implemented. A patch with xfstests for this feature will follow once there's agreement on this change/feature. Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> --- fs/btrfs/Makefile | 2 +- fs/btrfs/btrfs_inode.h | 1 + fs/btrfs/inode.c | 27 ++- fs/btrfs/ioctl.c | 131 +++++++++++++++ fs/btrfs/props.c | 389 ++++++++++++++++++++++++++++++++++++++++++++ fs/btrfs/props.h | 40 +++++ include/uapi/linux/btrfs.h | 12 ++ 7 files changed, 597 insertions(+), 5 deletions(-) create mode 100644 fs/btrfs/props.c create mode 100644 fs/btrfs/props.h