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Fix read on fuse host driver #519

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merged 3 commits into from
Jul 21, 2023
Merged

Fix read on fuse host driver #519

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45cff42
Add lock
vinc Jul 21, 2023
b0d650f
Rename fh to handle
vinc Jul 21, 2023
2cdeef0
Fix read with offset
vinc Jul 21, 2023
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201 changes: 105 additions & 96 deletions run/moros-fuse.py
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Original file line number Diff line number Diff line change
Expand Up @@ -6,6 +6,7 @@
from errno import ENOENT
from fuse import FUSE, FuseOSError, Operations, LoggingMixIn
from stat import S_IFDIR, S_IFREG
from threading import Lock

BLOCK_SIZE = 512
SUPERBLOCK_ADDR = 4096 * BLOCK_SIZE
Expand All @@ -24,6 +25,7 @@ class MorosFuse(LoggingMixIn, Operations):
getxattr = None

def __init__(self, path):
self.rwlock = Lock()
self.block_size = BLOCK_SIZE
self.image = open(path, "r+b")
self.image.seek(SUPERBLOCK_ADDR)
Expand Down Expand Up @@ -125,128 +127,135 @@ def destroy(self, path):
self.image.close()
return

def getattr(self, path, fh=None):
def getattr(self, path, handle=None):
(kind, addr, size, time, name) = self.__scan(path)
if addr == 0:
raise FuseOSError(ENOENT)
mode = S_IFDIR | 0o755 if kind == 0 else S_IFREG | 0o644
return { "st_atime": 0, "st_mtime": time, "st_uid": 0, "st_gid": 0, "st_mode": mode, "st_size": size }

def read(self, path, size, offset, fh):
(kind, next_block_addr, size, time, name) = self.__scan(path)
res = b""
while next_block_addr != 0 and size > 0:
self.image.seek(next_block_addr)
next_block_addr = int.from_bytes(self.image.read(4), "big") * self.block_size
if offset < self.block_size - 4:
buf = self.image.read(max(0, min(self.block_size - 4, size)))
res = b"".join([res, buf[offset:]])
offset = 0
else:
offset -= self.block_size - 4
size -= self.block_size - 4
return res
def read(self, path, size, offset, handle):
with self.rwlock:
(kind, next_block_addr, file_size, time, name) = self.__scan(path)
size = min(size, file_size - offset)
res = bytes()
while next_block_addr != 0 and size > 0:
self.image.seek(next_block_addr)
next_block_addr = int.from_bytes(self.image.read(4), "big") * self.block_size
if offset < self.block_size - 4:
buf = self.image.read(max(0, min(self.block_size - 4, size)))[offset:]
res += buf
size -= min(self.block_size - 4, len(buf))
offset = 0
else:
offset -= self.block_size - 4
return res

def readdir(self, path, fh):
files = [".", ".."]
(_, next_block_addr, _, _, _) = self.__scan(path)
for (kind, addr, size, time, name) in self.__read(next_block_addr):
files.append(name)
return files
def readdir(self, path, handle):
with self.rwlock:
files = [".", ".."]
(_, next_block_addr, _, _, _) = self.__scan(path)
for (kind, addr, size, time, name) in self.__read(next_block_addr):
files.append(name)
return files

def mkdir(self, path, mode):
self.create(path, S_IFDIR | mode)
with self.rwlock:
self.create(path, S_IFDIR | mode)

def create(self, path, mode):
(path, _, name) = path.rpartition("/")
entries = self.readdir(path + "/", 0)
entries.append(name)
pos = self.image.tell()
parent_addr = self.__update_dir_size(path, entries)
with self.rwlock:
(path, _, name) = path.rpartition("/")
entries = self.readdir(path + "/", 0)
entries.append(name)
pos = self.image.tell()
parent_addr = self.__update_dir_size(path, entries)

# Allocate space for the new dir entry if needed
blocks = 0
addr = parent_addr
next_addr = parent_addr
while next_addr != 0:
addr = next_addr
blocks += 1
self.image.seek(addr)
next_addr = int.from_bytes(self.image.read(4), "big") * self.block_size
free_size = (self.block_size - 4) - (pos - addr)
if free_size < ENTRY_SIZE + len(name):
pos = self.image.tell() - 4
# Allocate space for the new dir entry if needed
blocks = 0
addr = parent_addr
next_addr = parent_addr
while next_addr != 0:
addr = next_addr
blocks += 1
self.image.seek(addr)
next_addr = int.from_bytes(self.image.read(4), "big") * self.block_size
free_size = (self.block_size - 4) - (pos - addr)
if free_size < ENTRY_SIZE + len(name):
pos = self.image.tell() - 4
addr = self.__next_free_addr()
self.__alloc(addr)
self.image.seek(pos)
self.image.write((addr // self.block_size).to_bytes(4, "big"))
pos = addr + 4

# Allocate space for the new file
kind = int((mode & S_IFDIR) != S_IFDIR)
size = 0
addr = self.__next_free_addr()
self.__alloc(addr)

# Add dir entry
self.image.seek(pos)
self.image.write(kind.to_bytes(1, "big"))
self.image.write((addr // self.block_size).to_bytes(4, "big"))
pos = addr + 4
self.image.write(size.to_bytes(4, "big"))
self.image.write(int(time()).to_bytes(8, "big"))
self.image.write(len(name).to_bytes(1, "big"))
self.image.write(name.encode("utf-8"))
return 0

# Allocate space for the new file
kind = int((mode & S_IFDIR) != S_IFDIR)
size = 0
addr = self.__next_free_addr()
self.__alloc(addr)
def write(self, path, data, offset, handle):
with self.rwlock:
(_, addr, size, _, name) = self.__scan(path)
n = self.block_size - 4 # Space available for data in blocks
j = size % n # Start of space available in last block

# Add dir entry
self.image.seek(pos)
self.image.write(kind.to_bytes(1, "big"))
self.image.write((addr // self.block_size).to_bytes(4, "big"))
self.image.write(size.to_bytes(4, "big"))
self.image.write(int(time()).to_bytes(8, "big"))
self.image.write(len(name).to_bytes(1, "big"))
self.image.write(name.encode("utf-8"))
return 0

def write(self, path, data, offset, fh):
(_, addr, size, _, name) = self.__scan(path)
n = self.block_size - 4 # Space available for data in blocks
j = size % n # Start of space available in last block
# Update file size
self.image.seek(-(4 + 8 + 1 + len(name)), 1)
size = max(size, offset + len(data))
self.image.write(size.to_bytes(4, "big"))

# Update file size
self.image.seek(-(4 + 8 + 1 + len(name)), 1)
size = max(size, offset + len(data))
self.image.write(size.to_bytes(4, "big"))
for i in range(0, offset, n):
self.image.seek(addr)
next_addr = int.from_bytes(self.image.read(4), "big") * self.block_size
if i + n >= offset:
self.image.seek(addr + 4 + j)
self.image.write(data[0:(n - j)])
if next_addr == 0:
next_addr = self.__next_free_addr()
self.__alloc(next_addr)
self.image.seek(addr)
self.image.write((next_addr // self.block_size).to_bytes(4, "big"))
addr = next_addr

for i in range(0, offset, n):
self.image.seek(addr)
next_addr = int.from_bytes(self.image.read(4), "big") * self.block_size
if i + n >= offset:
self.image.seek(addr + 4 + j)
self.image.write(data[0:(n - j)])
if next_addr == 0:
next_addr = self.__next_free_addr()
self.__alloc(next_addr)
for i in range(n - j if j > 0 else 0, len(data), n):
next_addr = 0
if i + n < len(data): # TODO: check for off by one error
next_addr = self.__next_free_addr()
self.__alloc(next_addr)
self.image.seek(addr)
self.image.write((next_addr // self.block_size).to_bytes(4, "big"))
addr = next_addr
self.image.write(data[i:min(i + n, len(data))])
addr = next_addr

for i in range(n - j if j > 0 else 0, len(data), n):
next_addr = 0
if i + n < len(data): # TODO: check for off by one error
next_addr = self.__next_free_addr()
self.__alloc(next_addr)
self.image.seek(addr)
self.image.write((next_addr // self.block_size).to_bytes(4, "big"))
self.image.write(data[i:min(i + n, len(data))])
addr = next_addr

return len(data)
return len(data)

def unlink(self, path):
# Unlink and free blocs
(_, addr, size, _, name) = self.__scan(path)
self.image.seek(-(4 + 4 + 8 + 1 + len(name)), 1)
self.image.write((0).to_bytes(4, "big"))
while addr != 0:
self.__free(addr)
self.image.seek(addr)
addr = int.from_bytes(self.image.read(4), "big") * self.block_size
with self.rwlock:
# Unlink and free blocs
(_, addr, size, _, name) = self.__scan(path)
self.image.seek(-(4 + 4 + 8 + 1 + len(name)), 1)
self.image.write((0).to_bytes(4, "big"))
while addr != 0:
self.__free(addr)
self.image.seek(addr)
addr = int.from_bytes(self.image.read(4), "big") * self.block_size

# Update parent dir size
(path, _, _) = path.rpartition("/")
entries = self.readdir(path + "/", 0)
self.__update_dir_size(path, entries)
# Update parent dir size
(path, _, _) = path.rpartition("/")
entries = self.readdir(path + "/", 0)
self.__update_dir_size(path, entries)

if __name__ == '__main__':
import argparse
Expand Down