On 20/08/2024 13:23, Darrick J. Wong 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 to crash the kernel by breaking the >> + filesystem without its awareness, through direct block >> + device writes. Default is Y and can be changed through >> + the Kconfig option CONFIG_BLK_DEV_WRITE_MOUNTED. > > Can we mention that this also solves the problem of naïve storage > management tools (aka the ones that don't use O_EXCL) writing over a > mounted filesystem and trashing it? > > --D Sure! At least from my side, fine with that. How about the following string ? + 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 + filesystem without its awareness, through direct block + device writes. Also prevents issues from direct writes + of silly storage tooling (that doesn't use O_EXCL). The + default is Y and can be changed through the Kconfig + option CONFIG_BLK_DEV_WRITE_MOUNTED. But feel free to improve / change it. I'll wait more feedback and resubmit with a refined text. Cheers, Guilherme
