[BUG] smbfs: caching problems

From: Xuan Baldauf (xuan--lkml@baldauf.org)
Date: Sat Mar 31 2001 - 20:19:37 EST

  • Next message: Ketil Froyn: "oops in uhci.c running 2.4.2-ac28"

    Hello,

    there is something wrong with smbfs caching which makes my
    applications fail. The behaviour happens with
    linux-2.4.3-pre4 and linux-2.4.3-final.

    Consider following shell script: (where /mnt/n is a
    smbmounted smb share from a Win98SE box)

    router|/mnt/n/temp/smbfs> I=0; while test $I -lt 127; do
    echo "abc" >>/tmp/test.abc; I=$((I+1)); done # create a 508
    bytes file
    router|/mnt/n/temp/smbfs> I=0; while test $I -lt 129; do
    echo "xyz" >>/tmp/test.xyz; I=$((I+1)); done # create a 516
    bytes file
    router|/mnt/n/temp/smbfs> while true; do cp /tmp/test.abc
    testfile; tail -1 testfile; cp /tmp/test.xyz testfile; tail
    -1 testfile; done # copy the files alternatingly and read
    the destination file after it has bean overwritten
    abc
    abc
    abc
    abc
    abc
    abc
    abc
    abc
    abc
    abc
    abc
    abc
    abc
    abc
    abc
    abc
    abc
    abc
    abc
    abc
    abc
    [...Ctrl-C...]
    router|/mnt/n/temp/smbfs> cd /tmp # the same on reiserfs
    router|/tmp> while true; do cp /tmp/test.abc testfile; tail
    -1 testfile; cp /tmp/test.xyz testfile; tail -1 testfile;
    done # here it works
    abc
    xyz
    abc
    xyz
    abc
    xyz
    abc
    xyz
    abc
    xyz
    abc
    xyz
    abc
    xyz
    abc
    xyz
    abc
    xyz
    abc
    xyz
    abc
    xyz
    abc
    xyz
    abc
    xyz
    abc
    [...Ctrl-C...]
    router|/tmp> uname -a
    Linux router 2.4.3 #5 Fri Mar 30 14:02:24 CEST 2001 i586
    unknown
    router|/tmp>

    Obviously, the smbfs behaviour is wrong. Interstingly, the
    change in the filesize of the file overwritten seems to need
    to cross a 512-block-boundary in order to show the bug.

    Contact me if you need more info.

    Xuân.

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