Messages in this thread | | | Date | Mon, 17 Sep 2007 12:21:40 -0500 | From | Eric Sandeen <> | Subject | Re: [PATCH] ext34: ensure do_split leaves enough free space in both blocks |
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Eric Sandeen wrote: > The do_split() function for htree dir blocks is intended to split a > leaf block to make room for a new entry. It sorts the entries in the > original block by hash value, then moves the last half of the entries to > the new block - without accounting for how much space this actually moves. > (IOW, it moves half of the entry *count* not half of the entry *space*). > If by chance we have both large & small entries, and we move only the > smallest entries, and we have a large new entry to insert, we may not have > created enough space for it.
(btw, the upshot of this is that in add_dirent_to_buf(), memcpy(de->name, name, namelen) will overshoot the buffer and actually corrupt memory.)
:(
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