@@ -4,7 +4,7 @@
# LGPLv2 license
# Copyright Facebook 2014
-import sys,os,struct,fcntl,ctypes,stat
+import sys,os,struct,fcntl,ctypes,stat,argparse
# helpers for max ints
maxu64 = (1L << 64) - 1
@@ -65,6 +65,11 @@ BTRFS_DEV_STATS_KEY = 249
BTRFS_DEV_REPLACE_KEY = 250
BTRFS_STRING_ITEM_KEY = 253
+# store information about which extents are in use, and reference counts
+BTRFS_EXTENT_TREE_OBJECTID = 2
+
+BTRFS_BLOCK_GROUP_DATA = (1 << 0)
+
# in the kernel sources, this is flattened
# btrfs_ioctl_search_args_v2. It includes both the btrfs_ioctl_search_key
# and the buffer. We're using a 64K buffer size.
@@ -121,6 +126,13 @@ class btrfs_file_extent_item(ctypes.LittleEndianStructure):
("num_bytes", ctypes.c_ulonglong),
]
+class btrfs_block_group_item(ctypes.LittleEndianStructure):
+ _pack_ = 1
+ _fields_ = [ ("used", ctypes.c_ulonglong),
+ ("chunk_objectid", ctypes.c_ulonglong),
+ ("flags", ctypes.c_ulonglong),
+ ]
+
class btrfs_ioctl_search():
def __init__(self):
self.args = btrfs_ioctl_search_args()
@@ -288,9 +300,102 @@ def print_file_extents(filename):
float(st.st_size) / float(total_on_disk))
return 0
-if len(sys.argv) == 1:
- sys.stderr.write("Usage: btrfs-debug filename ...\n")
- sys.exit(1)
+def print_block_groups(mountpoint):
+ s = btrfs_ioctl_search()
+
+ s.args.min_type = BTRFS_BLOCK_GROUP_ITEM_KEY
+ s.args.max_type = BTRFS_BLOCK_GROUP_ITEM_KEY
+ s.args.tree_id = BTRFS_EXTENT_TREE_OBJECTID
+
+ min_used = maxu64
+ free_of_min_used = 0
+ bg_of_min_used = 0
+ total_free = 0
+
+ try:
+ fd = os.open(mountpoint, os.O_RDONLY)
+ st = os.fstat(fd)
+ except Exception, e:
+ sys.stderr.write("Failed to open %s (%s)\n" % (mountpoint, e))
+ return -1
+
+ while True:
+ try:
+ s.search(fd)
+ except Exception, e:
+ sys.stderr.write("Search ioctl failed for %s (%s)\n" % (mountpoint, e))
+ return -1
+
+ if s.args.nr_items == 0:
+ break
+
+ # p is the results buffer from kernel
+ p = ctypes.addressof(s.args.buf)
+ header = btrfs_ioctl_search_header()
+ header_size = ctypes.sizeof(header)
+ h = ctypes.addressof(header)
+ p_left = args_buffer_size
+
+ for x in xrange(0, s.args.nr_items):
+ # for each itme, copy the header from the buffer into
+ # our header struct
+ ctypes.memmove(h, p, header_size)
+ p += header_size
+ p_left -= header_size
+
+ # this would be a kernel bug it shouldn't be sending malformed
+ # items
+ if p_left <= 0:
+ break
+
+ if header.type == BTRFS_BLOCK_GROUP_ITEM_KEY:
+ bg = btrfs_block_group_item()
+
+ # this would be a kernel bug
+ if p_left < ctypes.sizeof(bg):
+ break
+
+ ctypes.memmove(ctypes.addressof(bg), p, ctypes.sizeof(bg))
+ if bg.flags & BTRFS_BLOCK_GROUP_DATA:
+ print "block group offset %Lu len %Lu used %Lu chunk_objectid %Lu flags %Lu usage %.2f" %\
+ (header.objectid, header.offset, bg.used, bg.chunk_objectid, bg.flags, float(bg.used) / float(header.offset))
+
+ total_free += (header.offset - bg.used)
+ if min_used >= bg.used:
+ min_used = bg.used
+ free_of_min_used = (header.offset - bg.used)
+ bg_of_min_used = header.objectid
+
+ p += header.len
+ p_left -= header.len
+ if p_left <= 0:
+ break
+
+ s.args.min_objectid = header.objectid
+
+ if s.args.min_objectid < maxu64:
+ s.args.min_objectid += 1
+ if s.args.min_objectid > s.args.max_objectid:
+ break
+
+ print "total_free %Lu min_used %Lu free_of_min_used %Lu block_group_of_min_used %Lu" %\
+ (total_free, min_used, free_of_min_used, bg_of_min_used)
+ if (total_free - free_of_min_used) >= min_used:
+ print "balance block group (%Lu) can reduce the number of data block group" % bg_of_min_used
+
+ return 0
+
+# main
+parser = argparse.ArgumentParser()
+parser.add_argument('path', nargs='+')
+parser.add_argument('-b', '--block-group', action='store_const', const=1, help='get block group information, use mountpoint as "path"')
+parser.add_argument('-f', '--file', action='store_const', const=1, help='get file mapping, use filepath')
+
+args = parser.parse_args()
-for f in sys.argv[1:]:
- print_file_extents(f)
+if args.block_group:
+ for i in args.path[0:]:
+ print_block_groups(i)
+elif args.file:
+ for f in args.path[0:]:
+ print_file_extents(f)