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I am using linux kernel 2.6.10 (from monta vista distribution) One of the partition in our device which was formated with ext3 file system, was re mounted with readonly access ...
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    In kernel ver 2.6.10 ext3 filesystem as readonly


    I am using linux kernel 2.6.10 (from monta vista distribution)
    One of the partition in our device which was formated with ext3 file system, was re mounted with readonly access after couple of months run.
    It was working fine for couple of months.
    After browsing I had found out that there is a bug in kernel.

    I know i should perform fsck on the file system to recover.

    My question is what is the reasons for file system to remount read only.

    This situation is realy annoying for us. we don't want this situation to ever occur. What are the precautionary measurement we need to take care. Is there any bug fix done in later kernel w.r.t to above bug.

    It would realy appreciated if some one throws light one this

  2. #2
    Trusted Penguin Irithori's Avatar
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    What makes you think, that this is a kernel bug?

    It can happen, that the kernel re-mounts a drive read-only.
    But for a very good reason: It has detected, that the drive and/or cabling is unreliable or faulty.

    So my advice would be:
    Make sure, your backup is working and up to date.
    Then test the drive/controller for errors.
    If there are any: replace the faulty parts.
    You must always face the curtain with a bow.

  3. #3
    Trusted Penguin Irithori's Avatar
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    And if there really was such a bug in 2.6.10 (link please),
    then you could consider an update.

    2.6.35 is already out and used by some desktop distributions,
    and even the more conservative server distributions like centos 5.5 run 2.6.18
    You must always face the curtain with a bow.

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    Quote Originally Posted by Irithori View Post
    And if there really was such a bug in 2.6.10 (link please),
    then you could consider an update.

    2.6.35 is already out and used by some desktop distributions,
    and even the more conservative server distributions like centos 5.5 run 2.6.18
    This is not hardware problem. We are using compact flash as storage device. Flash is partitioned into three part and all are formatted with ext3 file system. Out of three partition one partition is remounted as read only. if i do fsck on the file system it will work fine.

    i am not able to put URL
    {"You are only allowed to post URLs to other sites after you have made 15 posts or more"}

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    Trusted Penguin Irithori's Avatar
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    Compact flashs can also fail.
    Working for <long period of time> and then suddenly fail usually points to hardwareproblems in my experience.

    If you didnt reboot, you might still be able to see whether or not there are erros in dmesg.
    Should the problem re-occur it would be good to collect some logs.


    I couldnt find in a hurry, which kernel is the newest available for monatvista.
    But again, if you are sure it is a bug with 2.6.10, then update.
    You must always face the curtain with a bow.

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    As i told earlier it is not problem with hardware. We are facing the same problem in 2 more devices. It will work fine if we perform the fsck on it(it makes clear that there is no problem in hardware).
    i also not sure what exactly the bug in the kernel. from one thread i found that it is a bug in kernel whih aparently fixed in kernel 2.6.22

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    Linux Enthusiast Mudgen's Avatar
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    What bug number is it, in what bug tracking system? You don't need to post a URL to state that, then we can look it up.

    You're convinced that the fact that fsck repairs the problem proves that it's not a hardware issue? That's not correct.

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    Linux Engineer Segfault's Avatar
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    Right, this is no hardware problem. Ext3 writes journal in every 5 seconds, methinks? Flash memory has limited writes.
    1+1=0
    Is that what you are saying?

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    Linux Enthusiast Mudgen's Avatar
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    OTOH, there's no proof that it IS a hardware issue, either. One thing to rule out is a corrupted journal. You can remove it with the tune2fs -0^has_journal option, then add it back with -j. I've known this to correct situations where an ext3 would periodically flip to readonly, could be corrected with e2fsck, then would flip back some time later. Rinse, repeat.

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    Linux Engineer Segfault's Avatar
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    In fact, kernel mounts filesystems readonly when dirty bit is set or corruption is detected. Dirty bit it set when fsck mount count is exceeded or filesystem was not umounted at shutdown/disconnect. Not sure why your device gets mounted readonly, any of those conditions I mentioned is true?

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