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    SubjectLarge numbers of files.

    You can make a directory that is too large to be read with the
    usual tools. If you run this program, I'd suggest that you mount
    a "scrap" disk on /tmp, because you might have to use mke2fs to
    fix the mess.

    #include <stdio.h>
    #include <unistd.h>
    #include <signal.h>
    #include <fcntl.h>

    int sig = 1;

    void foo(int unused)
    sig = 0;
    int fd;
    int nam;
    int len;
    char fname[0x400];
    (void)signal(SIGINT, foo);
    (void)signal(SIGQUIT, foo);
    for(nam = 0;sig;nam++)
    len = sprintf(fname,"/tmp/file.%08x",nam);
    if((fd = open(fname, O_RDWR|O_CREAT, 0644)) > 0)
    if(write(fd, fname, len) == len)
    return 0;
    If you run this for a few seconds, you will find that the files
    exist in /tmp as expected.

    If you run this until it errors out from a full file-system, you
    (may) find....
    # rm -r /tmp <SEGFAULTS>
    # rm /tmp/file.00000000 <waits forever and can't be killed>
    # ls /tmp <waits forever and can't be killed>
    # vi /tmp/file.00000000 <waits forever and can't be killed>
    Converting the program to blindly remove each of the files fails
    with ENOENT.

    total: used: free: shared: buffers: cached:
    Mem: 31244288 28897280 2347008 7794688 6348800 15355904
    Swap: 133885952 0 133885952
    MemTotal: 30512 kB
    MemFree: 2292 kB
    MemShared: 7612 kB
    Buffers: 6200 kB
    Cached: 14996 kB
    SwapTotal: 130748 kB
    SwapFree: 130748 kB

    I used a 640 megabyte disk mounted ext2 on /tmp for this test.

    Dick Johnson
    ***** FILE SYSTEM MODIFIED *****
    Penguin : Linux version 2.1.113 on an i586 machine (66.15 BogoMips).
    Warning : It's hard to remain at the trailing edge of technology.

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      Last update: 2005-03-22 13:43    [from the cache]
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