Basic approach: have both ext4_max_bitmap_size() and ext4_max_size() functions to compute max offsets for both types of formats. Use vfs sb->s_maxbytes for the "native" maxbytes, i.e. extent-format files. Put the smaller bitmap limit in a new sbi->s_bitmap_maxbytes in the ext4 superblock info structure. Catch bitmap files in ext4_file_write() and ext4_setattr() to limit extending writes, llseeks, and truncates to too-large offsets which the VFS let through due to the extent-format maxbytes. On write, allow writes up to the max, but then stop, by using iov_shorten() to limit the size of the write to the maximum. 3 patches follow: ext4_two_maxbytes_functions.patch - differentiate the maxbytes f'ns ext4_bitmap_maxbytes_vfs.patch - export iov_shorten from kernel ext4_bitmap_maxbytes.patch - store, and limit to, bitmap_maxbytes Comments? Thanks, -Eric - 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
