On Fri, Aug 23, 2024 at 09:11:22AM -0700, Bart Van Assche wrote: > On 8/23/24 7:26 AM, Guilherme G. Piccoli wrote: > > + bdev_allow_write_mounted= > > + Format: <bool> > > + Control the ability of directly writing to mounted block > > + devices' page cache, i.e., allow / disallow writes that > > + bypasses the FS. This was implemented as a means to > > + prevent fuzzers from crashing the kernel by overwriting > > + the metadata underneath a mounted FS without its awareness. > > + This also prevents destructive formatting of mounted > > + filesystems by naive storage tooling that don't use > > + O_EXCL. Default is Y and can be changed through the > > + Kconfig option CONFIG_BLK_DEV_WRITE_MOUNTED. > > + > > Does this flag also affect direct I/O? If so, does this mean that the > reference to the page cache should be left out? I think it does affect directio, since the validation is done at open time via bdev_may_open, right? --D > Thanks, > > Bart.
