Re: [LTP] RFC: Failing fallocate tests ::::::

[Subrata M. <su...@li...>]

> Hi,
> 
> Please see an attached patch from Sharyathi for failing fallocate test
> cases.
> 

And Merged. Thanks Sharyathi.

--Subrata

> Regards & Thanks--
> Subrata Modak,
> ====================================
> ====================================
> 
> Omar,
>     Attaching the work around patch. This will address the problem until
> distros update with latest glibc which has fallocate implementation.
>     This is not extensively tested and built with some assumption
> like
>      o we are testing on x86* and ppc* archs
>      o on 64 bit machine we will always see 64 bit kernel running
> I dont think this needs to be pushed to LTP (any suggestions ??)
> But will definitely help you in your fallocate testing process.
> 
>              Thanks for all the help and guidance ...Amit, Aneesh, Sripathi
> Thanks
> Sharyathi
> 
> 
> Aneesh Kk Veetil wrote:
> > I guess it is more complicated than that.
> >
> > a) it is not 32 bit 64 bit issue.
> > b) It is due to compat layer of the kernel that enables 32 bit app run on
> a
> > 64 bit kernel.
> >
> > for 32 bit application running on a 32 bit kernel. Like x86 or ppc32 on a
> > ppc32 kernel the complier takes care of ABI
> > That means you can call the function as syscall(number, fd, mode, offset,
> > len). that is because both the user space and kernel space knows where
> > to look for the higher order bits. The problem happens when user space is
> > 32 bit  and kernel space is 64 bit.
> >
> > The easiest would be to build the test case using -m64 on powerpc and
> wait
> > for glibc support of fallocate. Because all these what you are doing are
> > going
> > to be irrelevant once glibc support fallocate. And F9 already have a
> glibc
> > that support the same.
> >
> > If you really want to fix this, then i would say you need #if ! defined
> > __powerpc64__  and inside that you need to find out you are running on a
> 64
> > bit kernel via
> > uname(2).
> >
> > -aneesh
> >
> >
> >
> >
> >
> 
> >              Amit K
> 
> >              Arora/India/IBM
> 
> >
> To
> >              02/04/2008 07:50          sha...@li...
> 
> >              PM
> cc
> >                                        Aneesh Kk Veetil/India/IBM@IBMIN,
> 
> >                                        Mohammed Omar/India/IBM@IBMIN,
> 
> >                                        Subrata Modak
> 
> >                                        <su...@li...>,
> 
> >                                        Supriya Kannery/India/IBM@IBMIN,
> 
> >                                        Suresh Kodati/India/IBM@IBMIN
> 
> >
> Subject
> >                                        Re: RFC: Failing fallocate tests
> 
> >                                        (Document link: Aneesh Kk Veetil)
> 
> >
> 
> >
> 
> >
> 
> >
> 
> >
> 
> >
> 
> >
> >
> >
> > Hi Sharyathi,
> >
> > The syscall macro is a temp. usage and finally at some point we will be
> > moving to fallocate() system call support in newer glibc. This is a
> problem
> > with the syscall macro and for now, we can have a work-around in your
> > testcase to take care of this 32 bit/ 64 bit compatibility issue. You may
> > want to break down the third and fourth arguments (which are 64 bits)
> into
> > pair of 2 arguments (of 32 bits each). But, this should be done only if
> > your testcase is compiled as a 32 bit binary. For 64 bit, it should work
> as
> > it is. This is what Aneesh tried and it worked.
> >
> > i.e. for 32 bit use something like :
> >
> > syscall(NR_FALLOCATE, fd, mode, (long)(offset >> 32), (long)(offset &&
> > (unsigned long long) 0x0000ffff),
> >                         (long)(length >> 32), (long)(length && (unsigned
> > long long) 0x0000ffff))
> >
> > and for 64 bit, use the existing stuff, i.e. :
> >
> > syscall(NR_FALLOCATE, fd, mode, offset, length)
> >
> >
> > Aneesh, any other suggestion ?
> >
> > Regards,
> > Amit Arora
> >
> >
> >
> 
> >              sha...@li...
> 
> >              et.ibm.com
> 
> >
> To
> >              02/04/08 07:40 PM         Mohammed Omar/India/IBM@IBMIN
> 
> >
> cc
> >                                        Aneesh Kk Veetil/India/IBM@IBMIN,
> 
> >                                        Subrata Modak
> 
> >                                        <su...@li...>, Amit
> 
> >                                        K Arora/India/IBM@IBMIN, Supriya
> 
> >                                        Kannery/India/IBM@IBMIN, Suresh
> 
> >                                        Kodati/India/IBM@IBMIN
> 
> >
> Subject
> >                                        RFC: Failing fallocate tests
> 
> >
> 
> >
> 
> >
> 
> >
> 
> >
> 
> >
> 
> >
> >
> >
> >
> > Hi
> >    Omar some time back observed that running fallocate tests on ppc64
> > machines comes out with "File too large" errors.
> >    This message comes from kernel and when we looked in more detail we
> > observed that this problem is noticed when libc provided is 32 bit and
> > kernel is 64 bit ie when application is 32 bit while the underlining
> > kernel is 64 bit.
> >    Since glibc doesn't provide support to fallocate we need to call the
> > system call with syscall() routine and not with the fallocate wrapper
> > which should have been provided by the glibc code.
> >
> > Problem:--
> >     In case application is 32 bit and kernel 64 bit, default system call
> > handler, sys_call, calls handler compat_sys_fallocate instead of
> > sys_fallocate (This decision is made with in kernel space not in the
> > user space). Since in this case the format in which they expect data is
> > deferent sys_fallocate sees huge values for the file offset as well as
> > for file length).
> >
> > Eg: sys_fallocate(int,int,long long,long long)
> >      compat_sys_fallocate(int,int,higher_int, lower_int, higher_int,
> > lower_int)
> >
> > Still working out how to over come this situation.
> > This mail was sent to give a heads up. Suggestions are highly
> appreciated.
> > Thanks
> > Sharyathi Nagesh
> >
> >
> >
> 
> --- Backup/fallocate01.c             2008-02-04 12:24:27.000000000 +0530
> +++ fallocate01.c        2008-02-07 12:07:29.000000000 +0530
> @@ -98,6 +98,7 @@
>  #include <sys/syscall.h>
>  #include <unistd.h>
>  #include <error.h>
> +#include <sys/utsname.h>
> 
>  /* Harness Specific Include Files. */
>  #include "test.h"
> @@ -303,9 +304,22 @@ main(int   ac,    /* number of command l
> 
> ******************************************************************************/
> 
>  static inline long fallocate(int fd, int mode, loff_t offset, loff_t len)
>  {
> -            return syscall(__NR_fallocate, fd, mode, offset,len);
> +            #if __WORDSIZE == 32
> +            struct utsname buf;
> +            if ( uname(&buf) == 0 ){
> +                        if(!strcmp(buf.machine,"ppc64") ||
> !strcmp(buf.machine,"x86_64"))
> +                                    return syscall(__NR_fallocate, fd,
> mode, (int)(offset>>32), (int)offset ,(int)(len>>32), (int)len);
> +            }
> +            else{
> +                        perror("uname:");
> +                        return -1;
> +                        }
> +            #endif
> +                        return syscall(__NR_fallocate, fd, mode,
> offset,len);
> +
>  }
> 
> +
> 
> /*****************************************************************************
> 
>   * Calls the system call, with appropriate parameters and writes data
> 
> ******************************************************************************/
> 
> --- Backup/fallocate02.c             2008-02-04 12:24:27.000000000 +0530
> +++ fallocate02.c        2008-02-07 12:10:34.000000000 +0530
> @@ -94,6 +94,7 @@
>  #include <sys/stat.h>
>  #include <sys/types.h>
>  #include <fcntl.h>
> +#include <sys/utsname.h>
> 
>  /* Harness Specific Include Files. */
>  #include "test.h"
> @@ -261,10 +262,23 @@ populate_file()
> 
> ******************************************************************************/
> 
>  static inline long fallocate(int fd, int mode, loff_t offset, loff_t len)
>  {
> -            return syscall(__NR_fallocate, fd, mode, offset,len);
> +            #if __WORDSIZE == 32
> +            struct utsname buf;
> +            if ( uname(&buf) == 0 ){
> +                        if(!strcmp(buf.machine,"ppc64") ||
> !strcmp(buf.machine,"x86_64"))
> +                                    return syscall(__NR_fallocate, fd,
> mode, (int)(offset>>32), (int)offset ,(int)(len>>32), (int)len);
> +            }
> +            else{
> +                        perror("uname:");
> +                        return -1;
> +                        }
> +            #endif
> +                        return syscall(__NR_fallocate, fd, mode,
> offset,len);
> +
>  }
> 
> 
> +
> 
> /*****************************************************************************
> 
>   * Main function that calls the system call with the  appropriate
> parameters
> 
> ******************************************************************************/
> 
> --- Backup/fallocate03.c             2008-02-04 12:24:27.000000000 +0530
> +++ fallocate03.c        2008-02-07 12:25:58.000000000 +0530
> @@ -92,6 +92,7 @@
>  #include <sys/types.h> //Can be done with out
>  #include <fcntl.h>
>  #include <unistd.h>
> +#include <sys/utsname.h>
> 
>  /* Harness Specific Include Files. */
>  #include "test.h"
> @@ -253,9 +254,22 @@ populate_file()
> 
> ******************************************************************************/
> 
>  static inline long fallocate(int fd, int mode, loff_t offset, loff_t len)
>  {
> -            return syscall(__NR_fallocate, fd, mode, offset,len);
> +            #if __WORDSIZE == 32
> +            struct utsname buf;
> +            if ( uname(&buf) == 0 ){
> +                        if(!strcmp(buf.machine,"ppc64") ||
> !strcmp(buf.machine,"x86_64"))
> +                                    return syscall(__NR_fallocate, fd,
> mode, (int)(offset>>32), (int)offset ,(int)(len>>32), (int)len);
> +            }
> +            else{
> +                        perror("uname:");
> +                        return -1;
> +                        }
> +            #endif
> +                        return syscall(__NR_fallocate, fd, mode,
> offset,len);
> +
>  }
> 
> +
> 
> /*****************************************************************************
> 
>   * Main function that calls the system call with the  appropriate
> parameters
> 
> ******************************************************************************/
> 
> 
> 
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