Massive pathwalk rewrite and cleanups. Several iterations had
been posted; hopefully the damn thing is getting readable and understandable
now. Pretty much all parts of pathname resolutions are affected...
The branch is identical to what has sat in -next, except for commit message in
"lift all calls of step_into() out of follow_dotdot/follow_dotdot_rcu",
crediting Qian Cai for reporting the bug; only commit message changed there.
I'd folded the fix back in Mar 25, and it had been present in -next since then
(see #work.dotdot). I asked Qian Cai whether he wanted his tested-by on that
thing, got no reply...
Anyway, all diffs in that branch are identical to the ones in
#work.dotdot, which is what has sat in linux-next for the last week.
The following changes since commit bb6d3fb354c5ee8d6bde2d576eb7220ea09862b9:
Linux 5.6-rc1 (2020-02-09 16:08:48 -0800)
are available in the git repository at:
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs.git work.dotdot1
for you to fetch changes up to 99a4a90c8e9337e364136393286544e3753673c3:
lookup_open(): don't bother with fallbacks to lookup+create (2020-04-02 01:09:31 -0400)
----------------------------------------------------------------
Al Viro (69):
do_add_mount(): lift lock_mount/unlock_mount into callers
fix automount/automount race properly
follow_automount(): get rid of dead^Wstillborn code
follow_automount() doesn't need the entire nameidata
make build_open_flags() treat O_CREAT | O_EXCL as implying O_NOFOLLOW
handle_mounts(): start building a sane wrapper for follow_managed()
atomic_open(): saner calling conventions (return dentry on success)
lookup_open(): saner calling conventions (return dentry on success)
do_last(): collapse the call of path_to_nameidata()
handle_mounts(): pass dentry in, turn path into a pure out argument
lookup_fast(): consolidate the RCU success case
teach handle_mounts() to handle RCU mode
lookup_fast(): take mount traversal into callers
step_into() callers: dismiss the symlink earlier
new step_into() flag: WALK_NOFOLLOW
fold handle_mounts() into step_into()
LOOKUP_MOUNTPOINT: fold path_mountpointat() into path_lookupat()
expand the only remaining call of path_lookup_conditional()
merging pick_link() with get_link(), part 1
merging pick_link() with get_link(), part 2
merging pick_link() with get_link(), part 3
merging pick_link() with get_link(), part 4
merging pick_link() with get_link(), part 5
merging pick_link() with get_link(), part 6
finally fold get_link() into pick_link()
sanitize handling of nd->last_type, kill LAST_BIND
namei: invert the meaning of WALK_FOLLOW
pick_link(): check for WALK_TRAILING, not LOOKUP_PARENT
link_path_walk(): simplify stack handling
namei: have link_path_walk() maintain LOOKUP_PARENT
massage __follow_mount_rcu() a bit
new helper: traverse_mounts()
atomic_open(): return the right dentry in FMODE_OPENED case
atomic_open(): lift the call of may_open() into do_last()
do_last(): merge the may_open() calls
do_last(): don't bother with keeping got_write in FMODE_OPENED case
do_last(): rejoing the common path earlier in FMODE_{OPENED,CREATED} case
do_last(): simplify the liveness analysis past finish_open_created
do_last(): rejoin the common path even earlier in FMODE_{OPENED,CREATED} case
split the lookup-related parts of do_last() into a separate helper
path_connected(): pass mount and dentry separately
path_parent_directory(): leave changing path->dentry to callers
expand path_parent_directory() in its callers
follow_dotdot{,_rcu}(): lift switching nd->path to parent out of loop
follow_dotdot{,_rcu}(): lift LOOKUP_BENEATH checks out of loop
move handle_dots(), follow_dotdot() and follow_dotdot_rcu() past step_into()
handle_dots(), follow_dotdot{,_rcu}(): preparation to switch to step_into()
follow_dotdot{,_rcu}(): switch to use of step_into()
lift all calls of step_into() out of follow_dotdot/follow_dotdot_rcu
follow_dotdot{,_rcu}(): massage loops
follow_dotdot_rcu(): be lazy about changing nd->path
follow_dotdot(): be lazy about changing nd->path
helper for mount rootwards traversal
non-RCU analogue of the previous commit
fs/namei.c: kill follow_mount()
pick_link(): pass it struct path already with normal refcounting rules
fold path_to_nameidata() into its only remaining caller
pick_link(): more straightforward handling of allocation failures
pick_link(): take reserving space on stack into a new helper
reserve_stack(): switch to __nd_alloc_stack()
__nd_alloc_stack(): make it return bool
link_path_walk(): sample parent's i_uid and i_mode for the last component
take post-lookup part of do_last() out of loop
open_last_lookups(): consolidate fsnotify_create() calls
open_last_lookups(): don't abuse complete_walk() when all we want is unlazy
open_last_lookups(): lift O_EXCL|O_CREAT handling into do_open()
open_last_lookups(): move complete_walk() into do_open()
atomic_open(): no need to pass struct open_flags anymore
lookup_open(): don't bother with fallbacks to lookup+create
Documentation/filesystems/path-lookup.rst | 7 +-
fs/autofs/dev-ioctl.c | 6 +-
fs/internal.h | 1 -
fs/namei.c | 1488 ++++++++++++-----------------
fs/namespace.c | 96 +-
fs/open.c | 4 +-
include/linux/namei.h | 4 +-
7 files changed, 687 insertions(+), 919 deletions(-)
