On 22/08/2024 22:27, Darrick J. Wong wrote:

[...]

quoted

+ 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 to crash the kernel by breaking the

                "...from crashing the kernel by overwriting
the metadata underneath a mounted filesystem without its awareness."

quoted

+ filesystem without its awareness, through direct block
+ device writes. Also prevents issues from direct writes

You can do it with buffered writes to the block device pagecache too.

"This also prevents destructive formatting of mounted filesystems by
naïve storage tooling that don't use O_EXCL."

--D

Thanks! Just sent the V2.