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    SubjectRe: Wrong free clusters count on FAT32
        Hi Ogawa (and Andrew) :)
    * OGAWA Hirofumi <> dixit:
    > Andrew Morton <> writes:
    > > Is there some way in which we can work out what's happened and fix
    > > it up?
    > It seems that the recent Windows changed specification, and it's
    > undocumented. Windows doesn't update ->free_clusters correctly.
    > Probably, what we can do is to throw away speed of statfs(2) and not
    > using ->free_clusters. (And if possible, recover it by optimization.)

    Even if Windows updates ->free_clusters correctly, it doesn't even
    consider it to compute the number of free clusters, and IMHO Linux
    should do the same. If speed is a concern, ->free_clusters can be
    computed at mount time. That way statfs won't slow.

    The problem is that if a program writes a file onto the filesystem
    without using statfs first to check for free space, the free_clusters
    entry won't have the real value and the driver may report "disk full" (I
    haven't read the code for the vfat driver, sorry, so I'm not sure about
    this) when really there are plenty of clusters to write the new file.

    Probably it's stupid to update the free clusters count at mount time
    (sorry if so...) but it looks like a good idea to me. And of course, I
    don't mean to update the value _on disk_, but the kernel's idea of free
    clusters (so even FAT filesystems mounted R/O will report correct

    Raúl Núñez de Arenas Coronado

    Linux Registered User 88736 |
    It's my PC and I'll cry if I want to... RAmen!
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