Messages in this thread | | | From | OGAWA Hirofumi <> | Subject | Re: [PATCH] fat: Support fallocate on fat. | Date | Mon, 09 Jul 2012 19:55:56 +0900 |
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Namjae Jeon <linkinjeon@gmail.com> writes:
>>> + /* >>> + * calculate i_blocks and mmu_private from the actual number of >>> + * allocated clusters instead of doing it from file size.This ensures >>> + * that the preallocated disk space using FALLOC_FL_KEEP_SIZE is >>> + * persistent across remounts and writes go into the allocated >>> clusters. >>> + */ >>> + fat_calc_dir_size(inode); >> >> Looks like the wrong. If you didn't initialize preallocated space, the >> data never be exposed to userland. It is security bug. > As explained above, if we do append write instead of seeking into a > random offset, there is no security risk.
So it means? - if we didn't, there is.
> The main disadvantage with initializing the preallocated space (as is > done in case of without FALLOC_FL_KEEP_SIZE ) is it takes long time > for bigger allocation sizes. It took ~70 seconds to preallocate 2GB on > our target if FALLOC_FL_KEEP_SIZE is not set.
It doesn't become the reason to expose uninitialized data.
Thanks. -- OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
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