[Bug 874] New: non-default extsize values introduces garbage into holey files

[bugzilla-daemon@xxxxxxxxxxx]

http://oss.sgi.com/bugzilla/show_bug.cgi?id=874

           Summary: non-default extsize values introduces garbage into
                    holey files
           Product: XFS
           Version: Current
          Platform: All
        OS/Version: Linux
            Status: NEW
          Severity: major
          Priority: P1
         Component: XFS kernel code
        AssignedTo: xfs-masters@xxxxxxxxxxx
        ReportedBy: gwehrman@xxxxxxx
   Estimated Hours: 0.0
    Classification: Unclassified


There is a bug in the XFS extsize allocation hint implementation.  Using
non-default values for the extsize attribute causes corruption in holey
files.  Follow is a reproducible test case.

#!/bin/sh

CMD="${0##*/}"
TDIR="testdir_$$"
NFILES="10"
EXTSIZE="256k"

# Create the test directory
mkdir ${TDIR}
cd ${TDIR}

# Set the test directory extsize
/usr/sbin/xfs_io > /dev/null <<EOF
open .
extsize ${EXTSIZE}
quit
EOF

# Create the binary to generate holey files
cat > bb.c <<EOF
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <stdio.h>
main()
{
        int fd;
        int j;
        int i;
        int buf[1024];
        fd = open("./filea",O_RDWR|O_CREAT,0666);
        for (i = 1; i < 9100; i++) {
                for (j = 0; j < 1024; j++) {
                        buf[j]  = i | i<<5;
                }
                if (write(fd,buf,253*4*sizeof(int))!= 253*4*sizeof(int)){
                        printf("Write did not return correct amount\n");
                }
                if (((i % 9) == 0) && (i < 9001))
                        lseek(fd, 4096*110,SEEK_CUR);
        }
        close(fd);
}
EOF
cc -o bb bb.c

# Create a set of holey files
echo "${CMD}: generating ${NFILES} files"
I=0
while [ ${I} -lt ${NFILES} ] ; do
  echo "filea_${I}"
  ./bb
  mv filea filea_${I}
  (( I += 1 ))
done

# Compare the files
echo "${CMD}: comparing files"
ERRCNT=0
I="0"
while [ ${I} -lt ${NFILES} ] ; do
  (( J = ${I} + 1 ))
  while [ ${J} -lt ${NFILES} ] ; do
    echo "cmp filea_${I} filea_${J}"
    if ! cmp filea_${I} filea_${J} ; then
      (( ERRCNT += 1 ))
    fi
    (( J += 1 ))
  done
  (( I += 1 ))
done

cd ..
if [ ${ERRCNT} -eq 0 ] ; then
  # cleanup on success
  rm -rf ${TDIR}
fi

echo "${CMD}: ${ERRCNT} errors"
exit ${ERRCNT}

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