Hi Allison, In thinking about fallocate() on tmpfs, I cross-check with ext4 and find this bug in its implementation of FALLOC_FL_PUNCH_HOLE: rm -f temp fallocate -l 4096 temp du temp # shows 4, right fallocate -p -l 4096 temp du temp # shows 0, right rm -f temp fallocate -n -l 4096 temp du temp # shows 4, right fallocate -p -l 4096 temp du temp # shows 4, wrong rm temp ext4_ext_punch_hole() contains /* No need to punch hole beyond i_size */ early return, and trimming to i_size below, but forgets that the other variety of fallocate(), with FALLOC_FL_KEEP_SIZE set, may have allocated blocks beyond i_size. They can be removed with ftruncate(), but it is unexpected for fallocate() not to undo its own work, and xfs does so. Hugh -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
