CIFS kernel module bug

Anton Altaparmakov aia21 at
Fri Sep 30 07:58:58 MDT 2011


Looking at the current kernel (in Linus' repository on github) there is a silly logic bug in the cifs module in fs/cifs/cifsfs.c::cifs_llseek() there is this bit of code:

	 * origin == SEEK_END || SEEK_DATA || SEEK_HOLE => we must revalidate
	 * the cached file length
	if (origin != SEEK_SET || origin != SEEK_CUR) {

The logical or should be a logical and, i.e. this should be:

	if (origin != SEEK_SET && origin != SEEK_CUR) {

As the code is at present that line is ALWAYS true because origin is ALWAYS either != SEEK_SET or != SEEK_CUR as if it equals one it cannot equal the other and vice versa…

So at the moment it always does the revalidation instead of only for SEEK_END, SEEK_DATA, and SEEK_HOLE.

Best regards,

Anton Altaparmakov <aia21 at> (replace at with @)
Unix Support, Computing Service, University of Cambridge, CB2 3QH, UK
Linux NTFS maintainer,

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