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#!/usr/bin/python3
import btrfs
import errno
import sys
if len(sys.argv) < 3:
print("Usage: {} <vaddr> <mountpoint>".format(sys.argv[0]))
sys.exit(1)
def using_v1(fd, vaddr):
return btrfs.ioctl.logical_ino(fd, vaddr)
def using_v2(fd, vaddr):
inodes, bytes_missed = btrfs.ioctl.logical_ino_v2(fd, vaddr, ignore_offset=True)
if bytes_missed > 0:
inodes, bytes_missed = \
btrfs.ioctl.logical_ino_v2(fd, vaddr, bufsize=65536+bytes_missed,
ignore_offset=True)
return inodes, bytes_missed
def find_out_about_v1_or_v2(fd, vaddr):
global logical_ino_fn
try:
inodes, bytes_missed = using_v2(fd, vaddr)
logical_ino_fn = using_v2
return inodes, bytes_missed
except IOError as e:
if e.errno == errno.ENOTTY:
inodes, bytes_missed = using_v1(fd, vaddr)
logical_ino_fn = using_v1
return inodes, bytes_missed
raise
vaddr = int(sys.argv[1])
path_cache = {}
with btrfs.FileSystem(sys.argv[2]) as fs:
block_group = fs.block_group(vaddr)
print(block_group)
logical_ino_fn = find_out_about_v1_or_v2
for extent in fs.extents(vaddr, vaddr + block_group.length - 1):
if isinstance(extent, btrfs.ctree.ExtentItem) \
and extent.flags & btrfs.ctree.EXTENT_FLAG_DATA:
print(extent)
inodes, bytes_missed = logical_ino_fn(fs.fd, extent.vaddr)
for inode in inodes:
if inode.root == btrfs.ctree.FS_TREE_OBJECTID or \
(inode.root >= btrfs.ctree.FIRST_FREE_OBJECTID and
inode.root <= btrfs.ctree.LAST_FREE_OBJECTID):
cache_key = (inode.root, inode.inum)
if cache_key not in path_cache:
try:
path = btrfs.ioctl.ino_lookup(fs.fd, treeid=inode.root,
objectid=inode.inum)[1][:-1]
path_cache[cache_key] = btrfs.utils.embedded_text_for_str(path)
except IOError as e:
if e.errno == errno.ENOENT:
path_cache[cache_key] = None
else:
raise
print(" root {} inode {} offset {} path {}".format(
inode.root, inode.inum, inode.offset, path_cache[cache_key]))
else:
print(" root {} inode {} offset {}".format(
inode.root, inode.inum, inode.offset))
if len(inodes) == 0 and logical_ino_fn == using_v1:
print(" [... no result and no kernel support for LOGICAL_INO_V2]")
if bytes_missed > 0:
if logical_ino_fn == using_v1:
print(" [... remainder can't be shown; no kernel support for LOGICAL_INO_V2]") # noqa
else:
print(" [... remainder can't be shown; too many items for buffer size]")
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