linux/include/uapi
Christian Brauner cdf930a009
fs: support FD_FAILFS_ROOT in fchdir()
Add a new file descriptor sentinel FD_FAILFS_ROOT following
FD_PIDFS_ROOT and FD_NSFS_ROOT and teach fchdir() to accept it. A
process calling fchdir(FD_FAILFS_ROOT) moves its working directory
into failfs. Every AT_FDCWD-relative lookup afterwards fails with
EOPNOTSUPP including "." and ".." and getcwd() reports the working
directory as unreachable from the process root by returning a path
prefixed with "(unreachable)". Lookups relative to explicit directory
file descriptors are unaffected.

The sentinel is the only way in. No privilege or gating is required.
Setting the working directory to a directory in which every operation
fails grants nothing and loses nothing that closing file descriptors
couldn't lose. An unlinked working directory behaves the same way today
modulo errno. The working directory also plays no role in confining ".."
resolution so no boundary is weakened.

Link: https://patch.msgid.link/20260724-work-failfs-v2-2-485dabbae185@kernel.org
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
2026-07-27 17:17:59 +02:00
..
asm-generic vfs-7.2-rc1.misc 2026-06-15 03:59:45 +05:30
cxl fwctl/cxl: Fix uuid_t usage in uapi 2025-04-11 20:45:43 -03:00
drm Merge tag 'drm-msm-next-2026-05-30' of https://gitlab.freedesktop.org/drm/msm into drm-next 2026-06-04 06:41:22 +10:00
fwctl fwctl/bnxt_fwctl: Add bnxt fwctl device 2026-03-31 13:33:54 -03:00
linux fs: support FD_FAILFS_ROOT in fchdir() 2026-07-27 17:17:59 +02:00
misc Char/Misc/IIO/Binder changes for 6.18-rc1 2025-10-04 16:26:32 -07:00
mtd
rdma RDMA/uverbs: Expose CoCo DMA bounce requirement to userspace 2026-05-29 20:27:29 -03:00
regulator regulator: uapi: Use UAPI integer type 2025-12-22 09:00:42 +00:00
scsi scsi: fc: Fix typo in fc_els.h 2026-03-27 16:35:04 -04:00
sound ASoC: SOF: ipc4-topology: Add new tokens for pipeline direction 2026-02-04 13:26:05 +00:00
video
xen
Kbuild