Merge branch 'for-linus-4.7' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs

Pull btrfs updates from Chris Mason:
 "This has our merge window series of cleanups and fixes.  These target
  a wide range of issues, but do include some important fixes for
  qgroups, O_DIRECT, and fsync handling.  Jeff Mahoney moved around a
  few definitions to make them easier for userland to consume.

  Also whiteout support is included now that issues with overlayfs have
  been cleared up.

  I have one more fix pending for page faults during btrfs_copy_from_user,
  but I wanted to get this bulk out the door first"

* 'for-linus-4.7' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: (90 commits)
  btrfs: fix memory leak during RAID 5/6 device replacement
  Btrfs: add semaphore to synchronize direct IO writes with fsync
  Btrfs: fix race between block group relocation and nocow writes
  Btrfs: fix race between fsync and direct IO writes for prealloc extents
  Btrfs: fix number of transaction units for renames with whiteout
  Btrfs: pin logs earlier when doing a rename exchange operation
  Btrfs: unpin logs if rename exchange operation fails
  Btrfs: fix inode leak on failure to setup whiteout inode in rename
  btrfs: add support for RENAME_EXCHANGE and RENAME_WHITEOUT
  Btrfs: pin log earlier when renaming
  Btrfs: unpin log if rename operation fails
  Btrfs: don't do unnecessary delalloc flushes when relocating
  Btrfs: don't wait for unrelated IO to finish before relocation
  Btrfs: fix empty symlink after creating symlink and fsync parent dir
  Btrfs: fix for incorrect directory entries after fsync log replay
  btrfs: build fixup for qgroup_account_snapshot
  btrfs: qgroup: Fix qgroup accounting when creating snapshot
  Btrfs: fix fspath error deallocation
  btrfs: make find_workspace warn if there are no workspaces
  btrfs: make find_workspace always succeed
  ...

2 files changed, 1148 insertions, 6 deletions

diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h
index dea893199257..23c6960e94a4 100644
--- a/include/uapi/linux/btrfs.h
+++ b/include/uapi/linux/btrfs.h
@@ -23,6 +23,7 @@
 
 #define BTRFS_IOCTL_MAGIC 0x94
 #define BTRFS_VOL_NAME_MAX 255
+#define BTRFS_LABEL_SIZE 256
 
 /* this should be 4k */
 #define BTRFS_PATH_NAME_MAX 4087
@@ -33,14 +34,31 @@ struct btrfs_ioctl_vol_args {
 
 #define BTRFS_DEVICE_PATH_NAME_MAX 1024
 
-#define BTRFS_SUBVOL_CREATE_ASYNC       (1ULL << 0)
-#define BTRFS_SUBVOL_RDONLY             (1ULL << 1)
-#define BTRFS_SUBVOL_QGROUP_INHERIT     (1ULL << 2)
+#define BTRFS_DEVICE_SPEC_BY_ID         (1ULL << 3)
+
+#define BTRFS_VOL_ARG_V2_FLAGS_SUPPORTED                \
+                        (BTRFS_SUBVOL_CREATE_ASYNC |    \
+                        BTRFS_SUBVOL_RDONLY |           \
+                        BTRFS_SUBVOL_QGROUP_INHERIT |   \
+                        BTRFS_DEVICE_SPEC_BY_ID)
+
 #define BTRFS_FSID_SIZE 16
 #define BTRFS_UUID_SIZE 16
 #define BTRFS_UUID_UNPARSED_SIZE        37
 
-#define BTRFS_QGROUP_INHERIT_SET_LIMITS (1ULL << 0)
+/*
+ * flags definition for qgroup limits
+ *
+ * Used by:
+ * struct btrfs_qgroup_limit.flags
+ * struct btrfs_qgroup_limit_item.flags
+ */
+#define BTRFS_QGROUP_LIMIT_MAX_RFER     (1ULL << 0)
+#define BTRFS_QGROUP_LIMIT_MAX_EXCL     (1ULL << 1)
+#define BTRFS_QGROUP_LIMIT_RSV_RFER     (1ULL << 2)
+#define BTRFS_QGROUP_LIMIT_RSV_EXCL     (1ULL << 3)
+#define BTRFS_QGROUP_LIMIT_RFER_CMPR    (1ULL << 4)
+#define BTRFS_QGROUP_LIMIT_EXCL_CMPR    (1ULL << 5)
 
 struct btrfs_qgroup_limit {
         __u64   flags;
@@ -50,6 +68,14 @@ struct btrfs_qgroup_limit {
         __u64   rsv_excl;
 };
 
+/*
+ * flags definition for qgroup inheritance
+ *
+ * Used by:
+ * struct btrfs_qgroup_inherit.flags
+ */
+#define BTRFS_QGROUP_INHERIT_SET_LIMITS (1ULL << 0)
+
 struct btrfs_qgroup_inherit {
         __u64   flags;
         __u64   num_qgroups;
@@ -64,6 +90,20 @@ struct btrfs_ioctl_qgroup_limit_args {
         struct btrfs_qgroup_limit lim;
 };
 
+/*
+ * flags for subvolumes
+ *
+ * Used by:
+ * struct btrfs_ioctl_vol_args_v2.flags
+ *
+ * BTRFS_SUBVOL_RDONLY is also provided/consumed by the following ioctls:
+ * - BTRFS_IOC_SUBVOL_GETFLAGS
+ * - BTRFS_IOC_SUBVOL_SETFLAGS
+ */
+#define BTRFS_SUBVOL_CREATE_ASYNC       (1ULL << 0)
+#define BTRFS_SUBVOL_RDONLY             (1ULL << 1)
+#define BTRFS_SUBVOL_QGROUP_INHERIT     (1ULL << 2)
+
 #define BTRFS_SUBVOL_NAME_MAX 4039
 struct btrfs_ioctl_vol_args_v2 {
         __s64 fd;
@@ -76,7 +116,10 @@ struct btrfs_ioctl_vol_args_v2 {
                 };
                 __u64 unused[4];
         };
-        char name[BTRFS_SUBVOL_NAME_MAX + 1];
+        union {
+                char name[BTRFS_SUBVOL_NAME_MAX + 1];
+                u64 devid;
+        };
 };
 
 /*
@@ -190,6 +233,37 @@ struct btrfs_ioctl_fs_info_args {
         __u64 reserved[122];                    /* pad to 1k */
 };
 
+/*
+ * feature flags
+ *
+ * Used by:
+ * struct btrfs_ioctl_feature_flags
+ */
+#define BTRFS_FEATURE_COMPAT_RO_FREE_SPACE_TREE (1ULL << 0)
+
+#define BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF    (1ULL << 0)
+#define BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL   (1ULL << 1)
+#define BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS     (1ULL << 2)
+#define BTRFS_FEATURE_INCOMPAT_COMPRESS_LZO     (1ULL << 3)
+/*
+ * some patches floated around with a second compression method
+ * lets save that incompat here for when they do get in
+ * Note we don't actually support it, we're just reserving the
+ * number
+ */
+#define BTRFS_FEATURE_INCOMPAT_COMPRESS_LZOv2   (1ULL << 4)
+
+/*
+ * older kernels tried to do bigger metadata blocks, but the
+ * code was pretty buggy.  Lets not let them try anymore.
+ */
+#define BTRFS_FEATURE_INCOMPAT_BIG_METADATA     (1ULL << 5)
+
+#define BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF    (1ULL << 6)
+#define BTRFS_FEATURE_INCOMPAT_RAID56           (1ULL << 7)
+#define BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA  (1ULL << 8)
+#define BTRFS_FEATURE_INCOMPAT_NO_HOLES         (1ULL << 9)
+
 struct btrfs_ioctl_feature_flags {
         __u64 compat_flags;
         __u64 compat_ro_flags;
@@ -254,6 +328,70 @@ struct btrfs_balance_progress {
         __u64 completed;        /* # of chunks relocated so far */
 };
 
+/*
+ * flags definition for balance
+ *
+ * Restriper's general type filter
+ *
+ * Used by:
+ * btrfs_ioctl_balance_args.flags
+ * btrfs_balance_control.flags (internal)
+ */
+#define BTRFS_BALANCE_DATA              (1ULL << 0)
+#define BTRFS_BALANCE_SYSTEM            (1ULL << 1)
+#define BTRFS_BALANCE_METADATA          (1ULL << 2)
+
+#define BTRFS_BALANCE_TYPE_MASK         (BTRFS_BALANCE_DATA |       \
+                                         BTRFS_BALANCE_SYSTEM |     \
+                                         BTRFS_BALANCE_METADATA)
+
+#define BTRFS_BALANCE_FORCE             (1ULL << 3)
+#define BTRFS_BALANCE_RESUME            (1ULL << 4)
+
+/*
+ * flags definitions for per-type balance args
+ *
+ * Balance filters
+ *
+ * Used by:
+ * struct btrfs_balance_args
+ */
+#define BTRFS_BALANCE_ARGS_PROFILES     (1ULL << 0)
+#define BTRFS_BALANCE_ARGS_USAGE        (1ULL << 1)
+#define BTRFS_BALANCE_ARGS_DEVID        (1ULL << 2)
+#define BTRFS_BALANCE_ARGS_DRANGE       (1ULL << 3)
+#define BTRFS_BALANCE_ARGS_VRANGE       (1ULL << 4)
+#define BTRFS_BALANCE_ARGS_LIMIT        (1ULL << 5)
+#define BTRFS_BALANCE_ARGS_LIMIT_RANGE  (1ULL << 6)
+#define BTRFS_BALANCE_ARGS_STRIPES_RANGE (1ULL << 7)
+#define BTRFS_BALANCE_ARGS_USAGE_RANGE  (1ULL << 10)
+
+#define BTRFS_BALANCE_ARGS_MASK                 \
+        (BTRFS_BALANCE_ARGS_PROFILES |          \
+         BTRFS_BALANCE_ARGS_USAGE |             \
+         BTRFS_BALANCE_ARGS_DEVID |             \
+         BTRFS_BALANCE_ARGS_DRANGE |            \
+         BTRFS_BALANCE_ARGS_VRANGE |            \
+         BTRFS_BALANCE_ARGS_LIMIT |             \
+         BTRFS_BALANCE_ARGS_LIMIT_RANGE |       \
+         BTRFS_BALANCE_ARGS_STRIPES_RANGE |     \
+         BTRFS_BALANCE_ARGS_USAGE_RANGE)
+
+/*
+ * Profile changing flags.  When SOFT is set we won't relocate chunk if
+ * it already has the target profile (even though it may be
+ * half-filled).
+ */
+#define BTRFS_BALANCE_ARGS_CONVERT      (1ULL << 8)
+#define BTRFS_BALANCE_ARGS_SOFT         (1ULL << 9)
+
+
+/*
+ * flags definition for balance state
+ *
+ * Used by:
+ * struct btrfs_ioctl_balance_args.state
+ */
 #define BTRFS_BALANCE_STATE_RUNNING     (1ULL << 0)
 #define BTRFS_BALANCE_STATE_PAUSE_REQ   (1ULL << 1)
 #define BTRFS_BALANCE_STATE_CANCEL_REQ  (1ULL << 2)
@@ -347,9 +485,45 @@ struct btrfs_ioctl_clone_range_args {
   __u64 dest_offset;
 };
 
-/* flags for the defrag range ioctl */
+/*
+ * flags definition for the defrag range ioctl
+ *
+ * Used by:
+ * struct btrfs_ioctl_defrag_range_args.flags
+ */
 #define BTRFS_DEFRAG_RANGE_COMPRESS 1
 #define BTRFS_DEFRAG_RANGE_START_IO 2
+struct btrfs_ioctl_defrag_range_args {
+        /* start of the defrag operation */
+        __u64 start;
+
+        /* number of bytes to defrag, use (u64)-1 to say all */
+        __u64 len;
+
+        /*
+         * flags for the operation, which can include turning
+         * on compression for this one defrag
+         */
+        __u64 flags;
+
+        /*
+         * any extent bigger than this will be considered
+         * already defragged.  Use 0 to take the kernel default
+         * Use 1 to say every single extent must be rewritten
+         */
+        __u32 extent_thresh;
+
+        /*
+         * which compression method to use if turning on compression
+         * for this defrag operation.  If unspecified, zlib will
+         * be used
+         */
+        __u32 compress_type;
+
+        /* spare for later */
+        __u32 unused[4];
+};
+
 
 #define BTRFS_SAME_DATA_DIFFERS 1
 /* For extent-same ioctl */
@@ -659,5 +833,7 @@ static inline char *btrfs_err_str(enum btrfs_err_code err_code)
                                    struct btrfs_ioctl_feature_flags[2])
 #define BTRFS_IOC_GET_SUPPORTED_FEATURES _IOR(BTRFS_IOCTL_MAGIC, 57, \
                                    struct btrfs_ioctl_feature_flags[3])
+#define BTRFS_IOC_RM_DEV_V2 _IOW(BTRFS_IOCTL_MAGIC, 58, \
+                                   struct btrfs_ioctl_vol_args_v2)
 
 #endif /* _UAPI_LINUX_BTRFS_H */
diff --git a/include/uapi/linux/btrfs_tree.h b/include/uapi/linux/btrfs_tree.h
new file mode 100644
index 000000000000..d5ad15a106a7
--- /dev/null
+++ b/include/uapi/linux/btrfs_tree.h
@@ -0,0 +1,966 @@
+#ifndef _BTRFS_CTREE_H_
+#define _BTRFS_CTREE_H_
+
+/*
+ * This header contains the structure definitions and constants used
+ * by file system objects that can be retrieved using
+ * the BTRFS_IOC_SEARCH_TREE ioctl.  That means basically anything that
+ * is needed to describe a leaf node's key or item contents.
+ */
+
+/* holds pointers to all of the tree roots */
+#define BTRFS_ROOT_TREE_OBJECTID 1ULL
+
+/* stores information about which extents are in use, and reference counts */
+#define BTRFS_EXTENT_TREE_OBJECTID 2ULL
+
+/*
+ * chunk tree stores translations from logical -> physical block numbering
+ * the super block points to the chunk tree
+ */
+#define BTRFS_CHUNK_TREE_OBJECTID 3ULL
+
+/*
+ * stores information about which areas of a given device are in use.
+ * one per device.  The tree of tree roots points to the device tree
+ */
+#define BTRFS_DEV_TREE_OBJECTID 4ULL
+
+/* one per subvolume, storing files and directories */
+#define BTRFS_FS_TREE_OBJECTID 5ULL
+
+/* directory objectid inside the root tree */
+#define BTRFS_ROOT_TREE_DIR_OBJECTID 6ULL
+
+/* holds checksums of all the data extents */
+#define BTRFS_CSUM_TREE_OBJECTID 7ULL
+
+/* holds quota configuration and tracking */
+#define BTRFS_QUOTA_TREE_OBJECTID 8ULL
+
+/* for storing items that use the BTRFS_UUID_KEY* types */
+#define BTRFS_UUID_TREE_OBJECTID 9ULL
+
+/* tracks free space in block groups. */
+#define BTRFS_FREE_SPACE_TREE_OBJECTID 10ULL
+
+/* device stats in the device tree */
+#define BTRFS_DEV_STATS_OBJECTID 0ULL
+
+/* for storing balance parameters in the root tree */
+#define BTRFS_BALANCE_OBJECTID -4ULL
+
+/* orhpan objectid for tracking unlinked/truncated files */
+#define BTRFS_ORPHAN_OBJECTID -5ULL
+
+/* does write ahead logging to speed up fsyncs */
+#define BTRFS_TREE_LOG_OBJECTID -6ULL
+#define BTRFS_TREE_LOG_FIXUP_OBJECTID -7ULL
+
+/* for space balancing */
+#define BTRFS_TREE_RELOC_OBJECTID -8ULL
+#define BTRFS_DATA_RELOC_TREE_OBJECTID -9ULL
+
+/*
+ * extent checksums all have this objectid
+ * this allows them to share the logging tree
+ * for fsyncs
+ */
+#define BTRFS_EXTENT_CSUM_OBJECTID -10ULL
+
+/* For storing free space cache */
+#define BTRFS_FREE_SPACE_OBJECTID -11ULL
+
+/*
+ * The inode number assigned to the special inode for storing
+ * free ino cache
+ */
+#define BTRFS_FREE_INO_OBJECTID -12ULL
+
+/* dummy objectid represents multiple objectids */
+#define BTRFS_MULTIPLE_OBJECTIDS -255ULL
+
+/*
+ * All files have objectids in this range.
+ */
+#define BTRFS_FIRST_FREE_OBJECTID 256ULL
+#define BTRFS_LAST_FREE_OBJECTID -256ULL
+#define BTRFS_FIRST_CHUNK_TREE_OBJECTID 256ULL
+
+
+/*
+ * the device items go into the chunk tree.  The key is in the form
+ * [ 1 BTRFS_DEV_ITEM_KEY device_id ]
+ */
+#define BTRFS_DEV_ITEMS_OBJECTID 1ULL
+
+#define BTRFS_BTREE_INODE_OBJECTID 1
+
+#define BTRFS_EMPTY_SUBVOL_DIR_OBJECTID 2
+
+#define BTRFS_DEV_REPLACE_DEVID 0ULL
+
+/*
+ * inode items have the data typically returned from stat and store other
+ * info about object characteristics.  There is one for every file and dir in
+ * the FS
+ */
+#define BTRFS_INODE_ITEM_KEY            1
+#define BTRFS_INODE_REF_KEY             12
+#define BTRFS_INODE_EXTREF_KEY          13
+#define BTRFS_XATTR_ITEM_KEY            24
+#define BTRFS_ORPHAN_ITEM_KEY           48
+/* reserve 2-15 close to the inode for later flexibility */
+
+/*
+ * dir items are the name -> inode pointers in a directory.  There is one
+ * for every name in a directory.
+ */
+#define BTRFS_DIR_LOG_ITEM_KEY  60
+#define BTRFS_DIR_LOG_INDEX_KEY 72
+#define BTRFS_DIR_ITEM_KEY      84
+#define BTRFS_DIR_INDEX_KEY     96
+/*
+ * extent data is for file data
+ */
+#define BTRFS_EXTENT_DATA_KEY   108
+
+/*
+ * extent csums are stored in a separate tree and hold csums for
+ * an entire extent on disk.
+ */
+#define BTRFS_EXTENT_CSUM_KEY   128
+
+/*
+ * root items point to tree roots.  They are typically in the root
+ * tree used by the super block to find all the other trees
+ */
+#define BTRFS_ROOT_ITEM_KEY     132
+
+/*
+ * root backrefs tie subvols and snapshots to the directory entries that
+ * reference them
+ */
+#define BTRFS_ROOT_BACKREF_KEY  144
+
+/*
+ * root refs make a fast index for listing all of the snapshots and
+ * subvolumes referenced by a given root.  They point directly to the
+ * directory item in the root that references the subvol
+ */
+#define BTRFS_ROOT_REF_KEY      156
+
+/*
+ * extent items are in the extent map tree.  These record which blocks
+ * are used, and how many references there are to each block
+ */
+#define BTRFS_EXTENT_ITEM_KEY   168
+
+/*
+ * The same as the BTRFS_EXTENT_ITEM_KEY, except it's metadata we already know
+ * the length, so we save the level in key->offset instead of the length.
+ */
+#define BTRFS_METADATA_ITEM_KEY 169
+
+#define BTRFS_TREE_BLOCK_REF_KEY        176
+
+#define BTRFS_EXTENT_DATA_REF_KEY       178
+
+#define BTRFS_EXTENT_REF_V0_KEY         180
+
+#define BTRFS_SHARED_BLOCK_REF_KEY      182
+
+#define BTRFS_SHARED_DATA_REF_KEY       184
+
+/*
+ * block groups give us hints into the extent allocation trees.  Which
+ * blocks are free etc etc
+ */
+#define BTRFS_BLOCK_GROUP_ITEM_KEY 192
+
+/*
+ * Every block group is represented in the free space tree by a free space info
+ * item, which stores some accounting information. It is keyed on
+ * (block_group_start, FREE_SPACE_INFO, block_group_length).
+ */
+#define BTRFS_FREE_SPACE_INFO_KEY 198
+
+/*
+ * A free space extent tracks an extent of space that is free in a block group.
+ * It is keyed on (start, FREE_SPACE_EXTENT, length).
+ */
+#define BTRFS_FREE_SPACE_EXTENT_KEY 199
+
+/*
+ * When a block group becomes very fragmented, we convert it to use bitmaps
+ * instead of extents. A free space bitmap is keyed on
+ * (start, FREE_SPACE_BITMAP, length); the corresponding item is a bitmap with
+ * (length / sectorsize) bits.
+ */
+#define BTRFS_FREE_SPACE_BITMAP_KEY 200
+
+#define BTRFS_DEV_EXTENT_KEY    204
+#define BTRFS_DEV_ITEM_KEY      216
+#define BTRFS_CHUNK_ITEM_KEY    228
+
+/*
+ * Records the overall state of the qgroups.
+ * There's only one instance of this key present,
+ * (0, BTRFS_QGROUP_STATUS_KEY, 0)
+ */
+#define BTRFS_QGROUP_STATUS_KEY         240
+/*
+ * Records the currently used space of the qgroup.
+ * One key per qgroup, (0, BTRFS_QGROUP_INFO_KEY, qgroupid).
+ */
+#define BTRFS_QGROUP_INFO_KEY           242
+/*
+ * Contains the user configured limits for the qgroup.
+ * One key per qgroup, (0, BTRFS_QGROUP_LIMIT_KEY, qgroupid).
+ */
+#define BTRFS_QGROUP_LIMIT_KEY          244
+/*
+ * Records the child-parent relationship of qgroups. For
+ * each relation, 2 keys are present:
+ * (childid, BTRFS_QGROUP_RELATION_KEY, parentid)
+ * (parentid, BTRFS_QGROUP_RELATION_KEY, childid)
+ */
+#define BTRFS_QGROUP_RELATION_KEY       246
+
+/*
+ * Obsolete name, see BTRFS_TEMPORARY_ITEM_KEY.
+ */
+#define BTRFS_BALANCE_ITEM_KEY  248
+
+/*
+ * The key type for tree items that are stored persistently, but do not need to
+ * exist for extended period of time. The items can exist in any tree.
+ *
+ * [subtype, BTRFS_TEMPORARY_ITEM_KEY, data]
+ *
+ * Existing items:
+ *
+ * - balance status item
+ *   (BTRFS_BALANCE_OBJECTID, BTRFS_TEMPORARY_ITEM_KEY, 0)
+ */
+#define BTRFS_TEMPORARY_ITEM_KEY        248
+
+/*
+ * Obsolete name, see BTRFS_PERSISTENT_ITEM_KEY
+ */
+#define BTRFS_DEV_STATS_KEY             249
+
+/*
+ * The key type for tree items that are stored persistently and usually exist
+ * for a long period, eg. filesystem lifetime. The item kinds can be status
+ * information, stats or preference values. The item can exist in any tree.
+ *
+ * [subtype, BTRFS_PERSISTENT_ITEM_KEY, data]
+ *
+ * Existing items:
+ *
+ * - device statistics, store IO stats in the device tree, one key for all
+ *   stats
+ *   (BTRFS_DEV_STATS_OBJECTID, BTRFS_DEV_STATS_KEY, 0)
+ */
+#define BTRFS_PERSISTENT_ITEM_KEY       249
+
+/*
+ * Persistantly stores the device replace state in the device tree.
+ * The key is built like this: (0, BTRFS_DEV_REPLACE_KEY, 0).
+ */
+#define BTRFS_DEV_REPLACE_KEY   250
+
+/*
+ * Stores items that allow to quickly map UUIDs to something else.
+ * These items are part of the filesystem UUID tree.
+ * The key is built like this:
+ * (UUID_upper_64_bits, BTRFS_UUID_KEY*, UUID_lower_64_bits).
+ */
+#if BTRFS_UUID_SIZE != 16
+#error "UUID items require BTRFS_UUID_SIZE == 16!"
+#endif
+#define BTRFS_UUID_KEY_SUBVOL   251     /* for UUIDs assigned to subvols */
+#define BTRFS_UUID_KEY_RECEIVED_SUBVOL  252     /* for UUIDs assigned to
+                                                 * received subvols */
+
+/*
+ * string items are for debugging.  They just store a short string of
+ * data in the FS
+ */
+#define BTRFS_STRING_ITEM_KEY   253
+
+
+
+/* 32 bytes in various csum fields */
+#define BTRFS_CSUM_SIZE 32
+
+/* csum types */
+#define BTRFS_CSUM_TYPE_CRC32   0
+
+/*
+ * flags definitions for directory entry item type
+ *
+ * Used by:
+ * struct btrfs_dir_item.type
+ */
+#define BTRFS_FT_UNKNOWN        0
+#define BTRFS_FT_REG_FILE       1
+#define BTRFS_FT_DIR            2
+#define BTRFS_FT_CHRDEV         3
+#define BTRFS_FT_BLKDEV         4
+#define BTRFS_FT_FIFO           5
+#define BTRFS_FT_SOCK           6
+#define BTRFS_FT_SYMLINK        7
+#define BTRFS_FT_XATTR          8
+#define BTRFS_FT_MAX            9
+
+/*
+ * The key defines the order in the tree, and so it also defines (optimal)
+ * block layout.
+ *
+ * objectid corresponds to the inode number.
+ *
+ * type tells us things about the object, and is a kind of stream selector.
+ * so for a given inode, keys with type of 1 might refer to the inode data,
+ * type of 2 may point to file data in the btree and type == 3 may point to
+ * extents.
+ *
+ * offset is the starting byte offset for this key in the stream.
+ *
+ * btrfs_disk_key is in disk byte order.  struct btrfs_key is always
+ * in cpu native order.  Otherwise they are identical and their sizes
+ * should be the same (ie both packed)
+ */
+struct btrfs_disk_key {
+        __le64 objectid;
+        __u8 type;
+        __le64 offset;
+} __attribute__ ((__packed__));
+
+struct btrfs_key {
+        __u64 objectid;
+        __u8 type;
+        __u64 offset;
+} __attribute__ ((__packed__));
+
+struct btrfs_dev_item {
+        /* the internal btrfs device id */
+        __le64 devid;
+
+        /* size of the device */
+        __le64 total_bytes;
+
+        /* bytes used */
+        __le64 bytes_used;
+
+        /* optimal io alignment for this device */
+        __le32 io_align;
+
+        /* optimal io width for this device */
+        __le32 io_width;
+
+        /* minimal io size for this device */
+        __le32 sector_size;
+
+        /* type and info about this device */
+        __le64 type;
+
+        /* expected generation for this device */
+        __le64 generation;
+
+        /*
+         * starting byte of this partition on the device,
+         * to allow for stripe alignment in the future
+         */
+        __le64 start_offset;
+
+        /* grouping information for allocation decisions */
+        __le32 dev_group;
+
+        /* seek speed 0-100 where 100 is fastest */
+        __u8 seek_speed;
+
+        /* bandwidth 0-100 where 100 is fastest */
+        __u8 bandwidth;
+
+        /* btrfs generated uuid for this device */
+        __u8 uuid[BTRFS_UUID_SIZE];
+
+        /* uuid of FS who owns this device */
+        __u8 fsid[BTRFS_UUID_SIZE];
+} __attribute__ ((__packed__));
+
+struct btrfs_stripe {
+        __le64 devid;
+        __le64 offset;
+        __u8 dev_uuid[BTRFS_UUID_SIZE];
+} __attribute__ ((__packed__));
+
+struct btrfs_chunk {
+        /* size of this chunk in bytes */
+        __le64 length;
+
+        /* objectid of the root referencing this chunk */
+        __le64 owner;
+
+        __le64 stripe_len;
+        __le64 type;
+
+        /* optimal io alignment for this chunk */
+        __le32 io_align;
+
+        /* optimal io width for this chunk */
+        __le32 io_width;
+
+        /* minimal io size for this chunk */
+        __le32 sector_size;
+
+        /* 2^16 stripes is quite a lot, a second limit is the size of a single
+         * item in the btree
+         */
+        __le16 num_stripes;
+
+        /* sub stripes only matter for raid10 */
+        __le16 sub_stripes;
+        struct btrfs_stripe stripe;
+        /* additional stripes go here */
+} __attribute__ ((__packed__));
+
+#define BTRFS_FREE_SPACE_EXTENT 1
+#define BTRFS_FREE_SPACE_BITMAP 2
+
+struct btrfs_free_space_entry {
+        __le64 offset;
+        __le64 bytes;
+        __u8 type;
+} __attribute__ ((__packed__));
+
+struct btrfs_free_space_header {
+        struct btrfs_disk_key location;
+        __le64 generation;
+        __le64 num_entries;
+        __le64 num_bitmaps;
+} __attribute__ ((__packed__));
+
+#define BTRFS_HEADER_FLAG_WRITTEN       (1ULL << 0)
+#define BTRFS_HEADER_FLAG_RELOC         (1ULL << 1)
+
+/* Super block flags */
+/* Errors detected */
+#define BTRFS_SUPER_FLAG_ERROR          (1ULL << 2)
+
+#define BTRFS_SUPER_FLAG_SEEDING        (1ULL << 32)
+#define BTRFS_SUPER_FLAG_METADUMP       (1ULL << 33)
+
+
+/*
+ * items in the extent btree are used to record the objectid of the
+ * owner of the block and the number of references
+ */
+
+struct btrfs_extent_item {
+        __le64 refs;
+        __le64 generation;
+        __le64 flags;
+} __attribute__ ((__packed__));
+
+struct btrfs_extent_item_v0 {
+        __le32 refs;
+} __attribute__ ((__packed__));
+
+
+#define BTRFS_EXTENT_FLAG_DATA          (1ULL << 0)
+#define BTRFS_EXTENT_FLAG_TREE_BLOCK    (1ULL << 1)
+
+/* following flags only apply to tree blocks */
+
+/* use full backrefs for extent pointers in the block */
+#define BTRFS_BLOCK_FLAG_FULL_BACKREF   (1ULL << 8)
+
+/*
+ * this flag is only used internally by scrub and may be changed at any time
+ * it is only declared here to avoid collisions
+ */
+#define BTRFS_EXTENT_FLAG_SUPER         (1ULL << 48)
+
+struct btrfs_tree_block_info {
+        struct btrfs_disk_key key;
+        __u8 level;
+} __attribute__ ((__packed__));
+
+struct btrfs_extent_data_ref {
+        __le64 root;
+        __le64 objectid;
+        __le64 offset;
+        __le32 count;
+} __attribute__ ((__packed__));
+
+struct btrfs_shared_data_ref {
+        __le32 count;
+} __attribute__ ((__packed__));
+
+struct btrfs_extent_inline_ref {
+        __u8 type;
+        __le64 offset;
+} __attribute__ ((__packed__));
+
+/* old style backrefs item */
+struct btrfs_extent_ref_v0 {
+        __le64 root;
+        __le64 generation;
+        __le64 objectid;
+        __le32 count;
+} __attribute__ ((__packed__));
+
+
+/* dev extents record free space on individual devices.  The owner
+ * field points back to the chunk allocation mapping tree that allocated
+ * the extent.  The chunk tree uuid field is a way to double check the owner
+ */
+struct btrfs_dev_extent {
+        __le64 chunk_tree;
+        __le64 chunk_objectid;
+        __le64 chunk_offset;
+        __le64 length;
+        __u8 chunk_tree_uuid[BTRFS_UUID_SIZE];
+} __attribute__ ((__packed__));
+
+struct btrfs_inode_ref {
+        __le64 index;
+        __le16 name_len;
+        /* name goes here */
+} __attribute__ ((__packed__));
+
+struct btrfs_inode_extref {
+        __le64 parent_objectid;
+        __le64 index;
+        __le16 name_len;
+        __u8   name[0];
+        /* name goes here */
+} __attribute__ ((__packed__));
+
+struct btrfs_timespec {
+        __le64 sec;
+        __le32 nsec;
+} __attribute__ ((__packed__));
+
+struct btrfs_inode_item {
+        /* nfs style generation number */
+        __le64 generation;
+        /* transid that last touched this inode */
+        __le64 transid;
+        __le64 size;
+        __le64 nbytes;
+        __le64 block_group;
+        __le32 nlink;
+        __le32 uid;
+        __le32 gid;
+        __le32 mode;
+        __le64 rdev;
+        __le64 flags;
+
+        /* modification sequence number for NFS */
+        __le64 sequence;
+
+        /*
+         * a little future expansion, for more than this we can
+         * just grow the inode item and version it
+         */
+        __le64 reserved[4];
+        struct btrfs_timespec atime;
+        struct btrfs_timespec ctime;
+        struct btrfs_timespec mtime;
+        struct btrfs_timespec otime;
+} __attribute__ ((__packed__));
+
+struct btrfs_dir_log_item {
+        __le64 end;
+} __attribute__ ((__packed__));
+
+struct btrfs_dir_item {
+        struct btrfs_disk_key location;
+        __le64 transid;
+        __le16 data_len;
+        __le16 name_len;
+        __u8 type;
+} __attribute__ ((__packed__));
+
+#define BTRFS_ROOT_SUBVOL_RDONLY        (1ULL << 0)
+
+/*
+ * Internal in-memory flag that a subvolume has been marked for deletion but
+ * still visible as a directory
+ */
+#define BTRFS_ROOT_SUBVOL_DEAD          (1ULL << 48)
+
+struct btrfs_root_item {
+        struct btrfs_inode_item inode;
+        __le64 generation;
+        __le64 root_dirid;
+        __le64 bytenr;
+        __le64 byte_limit;
+        __le64 bytes_used;
+        __le64 last_snapshot;
+        __le64 flags;
+        __le32 refs;
+        struct btrfs_disk_key drop_progress;
+        __u8 drop_level;
+        __u8 level;
+
+        /*
+         * The following fields appear after subvol_uuids+subvol_times
+         * were introduced.
+         */
+
+        /*
+         * This generation number is used to test if the new fields are valid
+         * and up to date while reading the root item. Every time the root item
+         * is written out, the "generation" field is copied into this field. If
+         * anyone ever mounted the fs with an older kernel, we will have
+         * mismatching generation values here and thus must invalidate the
+         * new fields. See btrfs_update_root and btrfs_find_last_root for
+         * details.
+         * the offset of generation_v2 is also used as the start for the memset
+         * when invalidating the fields.
+         */
+        __le64 generation_v2;
+        __u8 uuid[BTRFS_UUID_SIZE];
+        __u8 parent_uuid[BTRFS_UUID_SIZE];
+        __u8 received_uuid[BTRFS_UUID_SIZE];
+        __le64 ctransid; /* updated when an inode changes */
+        __le64 otransid; /* trans when created */
+        __le64 stransid; /* trans when sent. non-zero for received subvol */
+        __le64 rtransid; /* trans when received. non-zero for received subvol */
+        struct btrfs_timespec ctime;
+        struct btrfs_timespec otime;
+        struct btrfs_timespec stime;
+        struct btrfs_timespec rtime;
+        __le64 reserved[8]; /* for future */
+} __attribute__ ((__packed__));
+
+/*
+ * this is used for both forward and backward root refs
+ */
+struct btrfs_root_ref {
+        __le64 dirid;
+        __le64 sequence;
+        __le16 name_len;
+} __attribute__ ((__packed__));
+
+struct btrfs_disk_balance_args {
+        /*
+         * profiles to operate on, single is denoted by
+         * BTRFS_AVAIL_ALLOC_BIT_SINGLE
+         */
+        __le64 profiles;
+
+        /*
+         * usage filter
+         * BTRFS_BALANCE_ARGS_USAGE with a single value means '0..N'
+         * BTRFS_BALANCE_ARGS_USAGE_RANGE - range syntax, min..max
+         */
+        union {
+                __le64 usage;
+                struct {
+                        __le32 usage_min;
+                        __le32 usage_max;
+                };
+        };
+
+        /* devid filter */
+        __le64 devid;
+
+        /* devid subset filter [pstart..pend) */
+        __le64 pstart;
+        __le64 pend;
+
+        /* btrfs virtual address space subset filter [vstart..vend) */
+        __le64 vstart;
+        __le64 vend;
+
+        /*
+         * profile to convert to, single is denoted by
+         * BTRFS_AVAIL_ALLOC_BIT_SINGLE
+         */
+        __le64 target;
+
+        /* BTRFS_BALANCE_ARGS_* */
+        __le64 flags;
+
+        /*
+         * BTRFS_BALANCE_ARGS_LIMIT with value 'limit'
+         * BTRFS_BALANCE_ARGS_LIMIT_RANGE - the extend version can use minimum
+         * and maximum
+         */
+        union {
+                __le64 limit;
+                struct {
+                        __le32 limit_min;
+                        __le32 limit_max;
+                };
+        };
+
+        /*
+         * Process chunks that cross stripes_min..stripes_max devices,
+         * BTRFS_BALANCE_ARGS_STRIPES_RANGE
+         */
+        __le32 stripes_min;
+        __le32 stripes_max;
+
+        __le64 unused[6];
+} __attribute__ ((__packed__));
+
+/*
+ * store balance parameters to disk so that balance can be properly
+ * resumed after crash or unmount
+ */
+struct btrfs_balance_item {
+        /* BTRFS_BALANCE_* */
+        __le64 flags;
+
+        struct btrfs_disk_balance_args data;
+        struct btrfs_disk_balance_args meta;
+        struct btrfs_disk_balance_args sys;
+
+        __le64 unused[4];
+} __attribute__ ((__packed__));
+
+#define BTRFS_FILE_EXTENT_INLINE 0
+#define BTRFS_FILE_EXTENT_REG 1
+#define BTRFS_FILE_EXTENT_PREALLOC 2
+
+struct btrfs_file_extent_item {
+        /*
+         * transaction id that created this extent
+         */
+        __le64 generation;
+        /*
+         * max number of bytes to hold this extent in ram
+         * when we split a compressed extent we can't know how big
+         * each of the resulting pieces will be.  So, this is
+         * an upper limit on the size of the extent in ram instead of
+         * an exact limit.
+         */
+        __le64 ram_bytes;
+
+        /*
+         * 32 bits for the various ways we might encode the data,
+         * including compression and encryption.  If any of these
+         * are set to something a given disk format doesn't understand
+         * it is treated like an incompat flag for reading and writing,
+         * but not for stat.
+         */
+        __u8 compression;
+        __u8 encryption;
+        __le16 other_encoding; /* spare for later use */
+
+        /* are we inline data or a real extent? */
+        __u8 type;
+
+        /*
+         * disk space consumed by the extent, checksum blocks are included
+         * in these numbers
+         *
+         * At this offset in the structure, the inline extent data start.
+         */
+        __le64 disk_bytenr;
+        __le64 disk_num_bytes;
+        /*
+         * the logical offset in file blocks (no csums)
+         * this extent record is for.  This allows a file extent to point
+         * into the middle of an existing extent on disk, sharing it
+         * between two snapshots (useful if some bytes in the middle of the
+         * extent have changed
+         */
+        __le64 offset;
+        /*
+         * the logical number of file blocks (no csums included).  This
+         * always reflects the size uncompressed and without encoding.
+         */
+        __le64 num_bytes;
+
+} __attribute__ ((__packed__));
+
+struct btrfs_csum_item {
+        __u8 csum;
+} __attribute__ ((__packed__));
+
+struct btrfs_dev_stats_item {
+        /*
+         * grow this item struct at the end for future enhancements and keep
+         * the existing values unchanged
+         */
+        __le64 values[BTRFS_DEV_STAT_VALUES_MAX];
+} __attribute__ ((__packed__));
+
+#define BTRFS_DEV_REPLACE_ITEM_CONT_READING_FROM_SRCDEV_MODE_ALWAYS     0
+#define BTRFS_DEV_REPLACE_ITEM_CONT_READING_FROM_SRCDEV_MODE_AVOID      1
+#define BTRFS_DEV_REPLACE_ITEM_STATE_NEVER_STARTED      0
+#define BTRFS_DEV_REPLACE_ITEM_STATE_STARTED            1
+#define BTRFS_DEV_REPLACE_ITEM_STATE_SUSPENDED          2
+#define BTRFS_DEV_REPLACE_ITEM_STATE_FINISHED           3
+#define BTRFS_DEV_REPLACE_ITEM_STATE_CANCELED           4
+
+struct btrfs_dev_replace_item {
+        /*
+         * grow this item struct at the end for future enhancements and keep
+         * the existing values unchanged
+         */
+        __le64 src_devid;
+        __le64 cursor_left;
+        __le64 cursor_right;
+        __le64 cont_reading_from_srcdev_mode;
+
+        __le64 replace_state;
+        __le64 time_started;
+        __le64 time_stopped;
+        __le64 num_write_errors;
+        __le64 num_uncorrectable_read_errors;
+} __attribute__ ((__packed__));
+
+/* different types of block groups (and chunks) */
+#define BTRFS_BLOCK_GROUP_DATA          (1ULL << 0)
+#define BTRFS_BLOCK_GROUP_SYSTEM        (1ULL << 1)
+#define BTRFS_BLOCK_GROUP_METADATA      (1ULL << 2)
+#define BTRFS_BLOCK_GROUP_RAID0         (1ULL << 3)
+#define BTRFS_BLOCK_GROUP_RAID1         (1ULL << 4)
+#define BTRFS_BLOCK_GROUP_DUP           (1ULL << 5)
+#define BTRFS_BLOCK_GROUP_RAID10        (1ULL << 6)
+#define BTRFS_BLOCK_GROUP_RAID5         (1ULL << 7)
+#define BTRFS_BLOCK_GROUP_RAID6         (1ULL << 8)
+#define BTRFS_BLOCK_GROUP_RESERVED      (BTRFS_AVAIL_ALLOC_BIT_SINGLE | \
+                                         BTRFS_SPACE_INFO_GLOBAL_RSV)
+
+enum btrfs_raid_types {
+        BTRFS_RAID_RAID10,
+        BTRFS_RAID_RAID1,
+        BTRFS_RAID_DUP,
+        BTRFS_RAID_RAID0,
+        BTRFS_RAID_SINGLE,
+        BTRFS_RAID_RAID5,
+        BTRFS_RAID_RAID6,
+        BTRFS_NR_RAID_TYPES
+};
+
+#define BTRFS_BLOCK_GROUP_TYPE_MASK     (BTRFS_BLOCK_GROUP_DATA |    \
+                                         BTRFS_BLOCK_GROUP_SYSTEM |  \
+                                         BTRFS_BLOCK_GROUP_METADATA)
+
+#define BTRFS_BLOCK_GROUP_PROFILE_MASK  (BTRFS_BLOCK_GROUP_RAID0 |   \
+                                         BTRFS_BLOCK_GROUP_RAID1 |   \
+                                         BTRFS_BLOCK_GROUP_RAID5 |   \
+                                         BTRFS_BLOCK_GROUP_RAID6 |   \
+                                         BTRFS_BLOCK_GROUP_DUP |     \
+                                         BTRFS_BLOCK_GROUP_RAID10)
+#define BTRFS_BLOCK_GROUP_RAID56_MASK   (BTRFS_BLOCK_GROUP_RAID5 |   \
+                                         BTRFS_BLOCK_GROUP_RAID6)
+
+/*
+ * We need a bit for restriper to be able to tell when chunks of type
+ * SINGLE are available.  This "extended" profile format is used in
+ * fs_info->avail_*_alloc_bits (in-memory) and balance item fields
+ * (on-disk).  The corresponding on-disk bit in chunk.type is reserved
+ * to avoid remappings between two formats in future.
+ */
+#define BTRFS_AVAIL_ALLOC_BIT_SINGLE    (1ULL << 48)
+
+/*
+ * A fake block group type that is used to communicate global block reserve
+ * size to userspace via the SPACE_INFO ioctl.
+ */
+#define BTRFS_SPACE_INFO_GLOBAL_RSV     (1ULL << 49)
+
+#define BTRFS_EXTENDED_PROFILE_MASK     (BTRFS_BLOCK_GROUP_PROFILE_MASK | \
+                                         BTRFS_AVAIL_ALLOC_BIT_SINGLE)
+
+static inline __u64 chunk_to_extended(__u64 flags)
+{
+        if ((flags & BTRFS_BLOCK_GROUP_PROFILE_MASK) == 0)
+                flags |= BTRFS_AVAIL_ALLOC_BIT_SINGLE;
+
+        return flags;
+}
+static inline __u64 extended_to_chunk(__u64 flags)
+{
+        return flags & ~BTRFS_AVAIL_ALLOC_BIT_SINGLE;
+}
+
+struct btrfs_block_group_item {
+        __le64 used;
+        __le64 chunk_objectid;
+        __le64 flags;
+} __attribute__ ((__packed__));
+
+struct btrfs_free_space_info {
+        __le32 extent_count;
+        __le32 flags;
+} __attribute__ ((__packed__));
+
+#define BTRFS_FREE_SPACE_USING_BITMAPS (1ULL << 0)
+
+#define BTRFS_QGROUP_LEVEL_SHIFT                48
+static inline __u64 btrfs_qgroup_level(__u64 qgroupid)
+{
+        return qgroupid >> BTRFS_QGROUP_LEVEL_SHIFT;
+}
+
+/*
+ * is subvolume quota turned on?
+ */
+#define BTRFS_QGROUP_STATUS_FLAG_ON             (1ULL << 0)
+/*
+ * RESCAN is set during the initialization phase
+ */
+#define BTRFS_QGROUP_STATUS_FLAG_RESCAN         (1ULL << 1)
+/*
+ * Some qgroup entries are known to be out of date,
+ * either because the configuration has changed in a way that
+ * makes a rescan necessary, or because the fs has been mounted
+ * with a non-qgroup-aware version.
+ * Turning qouta off and on again makes it inconsistent, too.
+ */
+#define BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT   (1ULL << 2)
+
+#define BTRFS_QGROUP_STATUS_VERSION        1
+
+struct btrfs_qgroup_status_item {
+        __le64 version;
+        /*
+         * the generation is updated during every commit. As older
+         * versions of btrfs are not aware of qgroups, it will be
+         * possible to detect inconsistencies by checking the
+         * generation on mount time
+         */
+        __le64 generation;
+
+        /* flag definitions see above */
+        __le64 flags;
+
+        /*
+         * only used during scanning to record the progress
+         * of the scan. It contains a logical address
+         */
+        __le64 rescan;
+} __attribute__ ((__packed__));
+
+struct btrfs_qgroup_info_item {
+        __le64 generation;
+        __le64 rfer;
+        __le64 rfer_cmpr;
+        __le64 excl;
+        __le64 excl_cmpr;
+} __attribute__ ((__packed__));
+
+struct btrfs_qgroup_limit_item {
+        /*
+         * only updated when any of the other values change
+         */
+        __le64 flags;
+        __le64 max_rfer;
+        __le64 max_excl;
+        __le64 rsv_rfer;
+        __le64 rsv_excl;
+} __attribute__ ((__packed__));
+
+#endif /* _BTRFS_CTREE_H_ */