Introduce a new ioctl that uses the reverse mapping btree to return
information about the physical layout of the filesystem.  This is
the xfsprogs side of things for userspace support.

Signed-off-by: Darrick J. Wong <darrick.w...@oracle.com>
---
 libxfs/xfs_fs.h       |   65 +++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 106 insertions(+), 14 deletions(-)

diff --git a/libxfs/xfs_fs.h b/libxfs/xfs_fs.h
index d5ed090..6573fcc 100644
--- a/libxfs/xfs_fs.h
+++ b/libxfs/xfs_fs.h
@@ -117,6 +117,70 @@ struct getbmapx {
 #define BMV_OF_SHARED          0x8     /* segment shared with another file */
 
 /*
+ *     Structure for XFS_IOC_GETFSMAPX.
+ *
+ *     Similar to XFS_IOC_GETBMAPX, the first two elements in the array are
+ *     used to constrain the output.  The first element in the array should
+ *     represent the lowest disk address that the user wants to learn about.
+ *     The second element in the array should represent the highest disk
+ *     address to query.  Subsequent array elements will be filled out by the
+ *     command.
+ *
+ *     The fmv_iflags field is only used in the first structure.  The
+ *     fmv_oflags field is filled in for each returned structure after the
+ *     second structure.  The fmv_unused1 fields in the first two array
+ *     elements must be zero.
+ *
+ *     The fmv_count, fmv_entries, and fmv_iflags fields in the second array
+ *     element must be zero.
+ *
+ *     fmv_block, fmv_offset, and fmv_length are expressed in units of 512
+ *     byte sectors.
+ */
+#ifndef HAVE_GETFSMAPX
+struct getfsmapx {
+       __s64           fmv_device;     /* device id */
+       __s64           fmv_block;      /* starting block */
+       __s64           fmv_owner;      /* owner id */
+       __s64           fmv_offset;     /* file offset of segment */
+       __s64           fmv_length;     /* length of segment, blocks */
+       __s32           fmv_oflags;     /* mapping flags */
+       __s32           fmv_iflags;     /* control flags (1st structure) */
+       __s32           fmv_count;      /* # of entries in array incl. input */
+       __s32           fmv_entries;    /* # of entries filled in (output). */
+       __s64           fmv_unused1;    /* future use, must be zero */
+};
+#endif
+
+/*     fmv_device values - set by XFS_IOC_GETFSMAPX caller.    */
+/* use this value if the filesystem doesn't support multiple devices. */
+#define FMV_DEV_DEFAULT        0
+
+/*     fmv_flags values - set by XFS_IOC_GETFSMAPX caller.     */
+/* no flags defined yet */
+#define FMV_IF_VALID   0
+
+/*     fmv_flags values - returned for each non-header segment */
+#define FMV_OF_PREALLOC                0x1     /* segment = unwritten 
pre-allocation */
+#define FMV_OF_ATTR_FORK       0x2     /* segment = attribute fork */
+#define FMV_OF_EXTENT_MAP      0x4     /* segment = extent map */
+#define FMV_OF_SHARED          0x8     /* segment = shared with another file */
+#define FMV_OF_SPECIAL_OWNER   0x10    /* owner is a special value */
+#define FMV_OF_LAST            0x20    /* segment is the last in the FS */
+
+/*     fmv_owner special values */
+#define        FMV_OWN_FREE            (-1ULL) /* free space */
+#define FMV_OWN_UNKNOWN                (-2ULL) /* unknown owner */
+#define FMV_OWN_FS             (-3ULL) /* static fs metadata */
+#define FMV_OWN_LOG            (-4ULL) /* journalling log */
+#define FMV_OWN_AG             (-5ULL) /* per-AG metadata */
+#define FMV_OWN_INOBT          (-6ULL) /* inode btree blocks */
+#define FMV_OWN_INODES         (-7ULL) /* inodes */
+#define FMV_OWN_REFC           (-8ULL) /* refcount tree */
+#define FMV_OWN_COW            (-9ULL) /* cow allocations */
+#define FMV_OWN_DEFECTIVE      (-10ULL) /* bad blocks */
+
+/*
  * Structure for XFS_IOC_FSSETDM.
  * For use by backup and restore programs to set the XFS on-disk inode
  * fields di_dmevmask and di_dmstate.  These must be set to exactly and
@@ -523,6 +587,7 @@ typedef struct xfs_swapext
 #define XFS_IOC_GETBMAPX       _IOWR('X', 56, struct getbmap)
 #define XFS_IOC_ZERO_RANGE     _IOW ('X', 57, struct xfs_flock64)
 #define XFS_IOC_FREE_EOFBLOCKS _IOR ('X', 58, struct xfs_fs_eofblocks)
+#define XFS_IOC_GETFSMAPX      _IOWR('X', 59, struct getfsmapx)
 
 /*
  * ioctl commands that replace IRIX syssgi()'s
--
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