preallocate files without (posix_)fallocate or fcntl's F_PREALLOCATE?

2008-11-05 Thread Jeremy Messenger 

Hello folks,

At first, I don't really know C that well so... It's more of request or  
suggest if anyone is bored or interest to port on FreeBSD. :-)


Recently, Transmission has added preallocate files to prevent disk  
fragmentation but FreeBSD does not has any of (posix_)fallocate or fcntl's  
F_PREALLOCATE (checked in RELENG_7's src/* and manpages). Here's what it  
looks like:



static int
preallocateFile( int fd UNUSED, uint64_t length UNUSED )
{
#ifdef HAVE_FALLOCATE

return fallocate( fd, 0, offset, length );

#elif defined(HAVE_POSIX_FALLOCATE)

return posix_fallocate( fd, 0, length );

#elif defined(SYS_DARWIN)

fstore_t fst;
fst.fst_flags = F_ALLOCATECONTIG;
fst.fst_posmode = F_PEOFPOSMODE;
fst.fst_offset = 0;
fst.fst_length = length;
fst.fst_bytesalloc = 0;
return fcntl( fd, F_PREALLOCATE, fst );

#else

#warning no known method to preallocate files on this platform
return -1;

#endif
}


You can see a bit more over at  
http://trac.transmissionbt.com/changeset/7051 .. You can also point me to  
some sources if it exists for I can try do it by myself, but with lacking  
C knowledge is a bit hard for me at the most of time. I don't know if UFS  
does not need or does need it. If anyone is interesting to write simple  
one for FreeBSD will be cool. Thanks!


Cheers,
Mezz


--
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Re: preallocate files without (posix_)fallocate or fcntl's F_PREALLOCATE?

2008-11-05 Thread Ed Schouten 
Hello,

Not entirely related to this topic, but looking at the standards, it
seems we don't implement posix_fadvise() either. It seems we could
implement this as a no-op for now. It has no real advantage if we do,
but say, one day we gain real posix_fadvise() support, we already have a
bunch of binaries that have these performance optimisations compiled in.

Any comments?

-- 
 Ed Schouten [EMAIL PROTECTED]
 WWW: http://80386.nl/


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Re: preallocate files without (posix_)fallocate or fcntl's F_PREALLOCATE?

2008-11-05 Thread John Baldwin 
On Wednesday 05 November 2008 12:08:11 pm Jeremy Messenger wrote:
 Hello folks,
 
 At first, I don't really know C that well so... It's more of request or  
 suggest if anyone is bored or interest to port on FreeBSD. :-)
 
 Recently, Transmission has added preallocate files to prevent disk  
 fragmentation but FreeBSD does not has any of (posix_)fallocate or fcntl's  
 F_PREALLOCATE (checked in RELENG_7's src/* and manpages). Here's what it  
 looks like:
 
 
 static int
 preallocateFile( int fd UNUSED, uint64_t length UNUSED )
 {
 #ifdef HAVE_FALLOCATE
 
  return fallocate( fd, 0, offset, length );
 
 #elif defined(HAVE_POSIX_FALLOCATE)
 
  return posix_fallocate( fd, 0, length );
 
 #elif defined(SYS_DARWIN)
 
  fstore_t fst;
  fst.fst_flags = F_ALLOCATECONTIG;
  fst.fst_posmode = F_PEOFPOSMODE;
  fst.fst_offset = 0;
  fst.fst_length = length;
  fst.fst_bytesalloc = 0;
  return fcntl( fd, F_PREALLOCATE, fst );
 
 #else
 
  #warning no known method to preallocate files on this platform
  return -1;
 
 #endif
 }
 
 
 You can see a bit more over at  
 http://trac.transmissionbt.com/changeset/7051 .. You can also point me to  
 some sources if it exists for I can try do it by myself, but with lacking  
 C knowledge is a bit hard for me at the most of time. I don't know if UFS  
 does not need or does need it. If anyone is interesting to write simple  
 one for FreeBSD will be cool. Thanks!

UFS would benefit.  See the notes on MAP_NOSYNC in mmap(2).  Peter Wemm 
(peter@) probably can give a more detailed suggestion of what you would need 
to do.  Doing it efficiently would probably require a new VOP_ALLOCATE() or 
some such.

-- 
John Baldwin
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