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| author | Mickaël Salaün <mic@digikod.net> | 2023-06-12 21:14:25 +0200 |
|---|---|---|
| committer | Mickaël Salaün <mic@digikod.net> | 2023-06-12 21:26:19 +0200 |
| commit | 74ce793bcbde5cef0f82d6ccb3c47cb651295a9a (patch) | |
| tree | af52b942aba6e0539e65ebfced7d46f8bb770cfd /arch | |
| parent | 858fd168a95c5b9669aac8db6c14a9aeab446375 (diff) | |
| download | linux-stable-74ce793bcbde5cef0f82d6ccb3c47cb651295a9a.tar.gz linux-stable-74ce793bcbde5cef0f82d6ccb3c47cb651295a9a.tar.bz2 linux-stable-74ce793bcbde5cef0f82d6ccb3c47cb651295a9a.zip | |
hostfs: Fix ephemeral inodes
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 opened,
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
changes.
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@cambridgegreys.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Richard Weinberger <richard@nod.at>
Link: https://lore.kernel.org/r/20230612191430.339153-2-mic@digikod.net
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/Kconfig | 7 | ||||
| -rw-r--r-- | arch/um/Kconfig | 1 |
2 files changed, 0 insertions, 8 deletions
diff --git a/arch/Kconfig b/arch/Kconfig index 205fd23e0cad..49996ee9e33b 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -1188,13 +1188,6 @@ config COMPAT_32BIT_TIME config ARCH_NO_PREEMPT bool -config ARCH_EPHEMERAL_INODES - def_bool n - help - An arch should select this symbol if it doesn't keep track of inode - instances on its own, but instead relies on something else (e.g. the - host kernel for an UML kernel). - config ARCH_SUPPORTS_RT bool diff --git a/arch/um/Kconfig b/arch/um/Kconfig index 541a9b18e343..4057d5267c6a 100644 --- a/arch/um/Kconfig +++ b/arch/um/Kconfig @@ -5,7 +5,6 @@ menu "UML-specific options" config UML bool default y - select ARCH_EPHEMERAL_INODES select ARCH_HAS_FORTIFY_SOURCE select ARCH_HAS_GCOV_PROFILE_ALL select ARCH_HAS_KCOV |