2010/11/29 Suresh Jayaraman <[email protected]>:
> On 11/29/2010 04:30 PM, Pavel Shilovsky wrote:
>> 2010/11/29 Suresh Jayaraman <[email protected]>:
>>> On 11/28/2010 01:42 PM, Pavel Shilovsky wrote:
>>>> Re-posting the whole set of strict cache patches.
>>>
>>> I try to explain here the "strict cache" semantics as I'm not sure
>>> whether I understand it clearly. Please correct me if I'm wrong.
>>>
>>> Strict cache semantics
>>>
>>> �o provides stricter cache coherency among cifs clients that access
>>> � �the same files.
>>> �o The clients will read data from the Server always, except when they
>>> � �hold read oplock or Level II oplock on the file.
>>> �o The clients will write data to the Server always, except when they
>>> � �hold exclusive oplock on the file.
>>> �o When we close the last filehandle of the inode, file should be
>>> � �marked for revalidation as it is possible for the client to access
>>> � �stale data from the cache when we open it again with a read
>>> � �oplock.
>>> �o On fsync/mmap, invalidate inode if read oplock has not been set.
>>>
>>>
>>> Is this the semantics being proposed? Did I miss anything?
>>
>> Yes, you are right - it is exactly what I mean.
>>
>
> Also, would be good to know what level of testing these patches have
> undergone. Could you share the test results as well?
>
I don't run big stress tests over it but I have tree small tests that
shows the problem this mode is going to fix.
--
Best regards,
Pavel Shilovsky.
#!/bin/env python
#
# We have to mount the same share to test, test1, test2 directories that locate in the directory we
# execute this script from.
from os import open, close, O_RDWR, O_CREAT, write, read, O_RDONLY, O_WRONLY, O_TRUNC, lseek, SEEK_END, SEEK_SET
f = open('test/_test4321_', O_RDWR | O_CREAT | O_TRUNC)
close(f)
f1 = open('test1/_test4321_', O_RDWR)
write(f1, 'a')
close(f1)
f2 = open('test2/_test4321_', O_WRONLY)
write(f2, 'x')
close(f2)
f3 = open('test1/_test4321_', O_RDONLY)
print 'must be x:', read(f3, 1)
close(f3)
#!/bin/env python
#
# We have to mount the same share to test, test1, test2 directories that locate in the directory we
# execute this script from.
from os import open, close, O_RDWR, O_CREAT, write, read, O_RDONLY, O_WRONLY, O_TRUNC, lseek, SEEK_END, SEEK_SET
f = open('test/_test4321_', O_RDWR | O_CREAT | O_TRUNC)
close(f)
f1 = open('test1/_test4321_', O_RDWR)
write(f1, 'a')
f2 = open('test2/_test4321_', O_WRONLY)
write(f2, 'x')
f3 = open('test1/_test4321_', O_RDONLY)
print 'must be x:', read(f3, 1)
close(f1)
close(f2)
close(f3)
#!/bin/env python
#
# We have to mount the same share to test, test1, test2 directories that locate in the directory we
# execute this script from.
from os import open, close, O_RDWR, O_CREAT, write, read, O_RDONLY, O_WRONLY, O_TRUNC, lseek
f = open('test/_test4321_', O_RDWR | O_CREAT | O_TRUNC)
write(f, ''.join('a' for _ in range(4096)))
close(f)
f1 = open('test1/_test4321_', O_RDWR)
f2 = open('test2/_test4321_', O_RDWR)
write(f1, 'x')
print 'x is written through f1'
print '%c is read from f2' % read(f2, 1)
write(f1, 'y')
print 'y is written through f1'
print '%c is read from f2' % read(f2, 1)
write(f1, 'z')
print 'z is written through f1'
print '%c is read from f2' % read(f2, 1)
close(f1)
close(f2)
