Re: 2.6.19-rc2-mm2 : empty files on vfat file system

OGAWA Hirofumi
2006-10-21T13:29:54Z

OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> writes:

> Damien Wyart <damien.wyart@free.fr> writes:
>
>> I have noticed something strange (and bad :) since using 2.6.19-rc2-mm2
>> (the problem is NOT present on 2.6.19-rc2-mm1 ; do not know for
>> mainline, I have not been able to test yet, but I think there have not
>> been recent changes in this area) : writing a file to a vfat
>> fs (fat 32) writes it, but with size 0 and no content. All this is
>> silent : no error message, nothing in the logs. After several attempts,
>> I checked the fs with fsck.vfat and it reported errors about some of the
>> files and told it was truncating them to size 0 (but their displayed
>> size was already 0, btw).
>
> diff -puN fs/fat/inode.c~fs-prepare_write-fixes fs/fat/inode.c
> --- a/fs/fat/inode.c~fs-prepare_write-fixes
> +++ a/fs/fat/inode.c
> @@ -150,7 +150,11 @@ static int fat_commit_write(struct file
> unsigned from, unsigned to)
> {
> struct inode *inode = page->mapping->host;
> - int err = generic_commit_write(file, page, from, to);
> + int err;
> + if (to - from > 0)
> + return 0;
> +
> + err = generic_commit_write(file, page, from, to);
> if (!err && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) {
> inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
> MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
>
> This change does't update ->i_size. Could you just delete, and test it?
> Anyway, this seems wrong even if it's "if ((to - from) == 0)". The zero
> range is valid for cont_prepare_write()...

s/cont_prepare_write/generic_cont_expand/.
--
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>