----- Ursprüngliche Mail ----- > Von: "Mickaël Salaün" <mic@xxxxxxxxxxx> > hostfs creates a new inode for each opened or created file, which created > useless inode allocations and forbade identifying a host file with a kernel > inode. > > Fix this uncommon filesystem behavior by tying kernel inodes to host > file's inode and device IDs. Even if the host filesystem inodes may be > recycled, this cannot happen while a file referencing it is open, which > is the case with hostfs. It should be noted that hostfs inode IDs may > not be unique for the same hostfs superblock because multiple host's > (backed) superblocks may be used. > > Delete inodes when dropping them to force backed host's file descriptors > closing. > > This enables to entirely remove ARCH_EPHEMERAL_INODES, and then makes > Landlock fully supported by UML. This is very useful for testing > (ongoing and backported) changes. Removing ARCH_EPHEMERAL_INODES should be a patch on its own, IMHO. > These changes also factor out and simplify some helpers thanks to the > new hostfs_inode_update() and the hostfs_iget() revamp: read_name(), > hostfs_create(), hostfs_lookup(), hostfs_mknod(), and > hostfs_fill_sb_common(). > > A following commit with new Landlock tests check this new hostfs inode > consistency. > > Cc: Anton Ivanov <anton.ivanov@xxxxxxxxxxxxxxxxxx> > Cc: Johannes Berg <johannes@xxxxxxxxxxxxxxxx> > Cc: Richard Weinberger <richard@xxxxxx> > Cc: <stable@xxxxxxxxxxxxxxx> # 5.15.x: ce72750f04d6: hostfs: Fix writeback of > dirty pages > Cc: <stable@xxxxxxxxxxxxxxx> # 5.15+ I'm not sure whether this patch qualifies as stable material. While I fully agree that the current behavoir is odd, nothing user visible is really broken so far. > Signed-off-by: Mickaël Salaün <mic@xxxxxxxxxxx> > Link: https://lore.kernel.org/r/20230309165455.175131-2-mic@xxxxxxxxxxx Other than that, patch looks good to me. Thanks, //richard
