[Considerably grown since the last time it had been posted - see
https://lore.kernel.org/all/20251129170142.150639-1-viro@zeniv.linux.org.uk/
for previous variant]
Changes compared to v2:
* rebased to v6.19-rc1, dropped mguzik's patch merged in mainline
* size of embedded name bumped up, so that sizeof(struct filename)
ends up being 192 bytes (64-byte aligned and large enough to cover everything
realistic).
* in #17 ("allow incomplete imports of filenames") don't open-code
getname_kernel() in the "copy" case.
* taken out ntfs (ab)uses of names_cachep added this cycle
* add CLASS() machinery for struct filename; it fits most of the
users. Plenty of conversions later in the series...
* most of the pathwalk-related API does the right thing on ERR_PTR()
passed as filename; the only exception is do_filp_open(), that needs to have
that checked in its callers. Moved the check into it, simplified the callers
(and in some cases callers of callers, and...)
* renamed 'do_filp_open' to 'do_file_open' - should've been called
that way from the very beginning. My fault, back in 2.1.128, when cretinous
filp_open() had been added ;-/
* alpha osf_mount() device name imports are done the same way as
the regular mount() does - strndup_user()
* sysfs(2) (no relation to sysfs) used to abuse getname() for
importing filesystem type name; no more.
The branch lives in
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs.git #work.filename
now; individual patches in followups.
Review and testing would be very welcome; it seems to survive the local
beating, but...
Shortlog:
Al Viro (58):
do_faccessat(): import pathname only once
do_fchmodat(): import pathname only once
do_fchownat(): import pathname only once
do_utimes_path(): import pathname only once
chdir(2): import pathname only once
chroot(2): import pathname only once
user_statfs(): import pathname only once
do_sys_truncate(): import pathname only once
do_readlinkat(): import pathname only once
get rid of audit_reusename()
ntfs: ->d_compare() must not block
getname_flags() massage, part 1
getname_flags() massage, part 2
struct filename: use names_cachep only for getname() and friends
struct filename: saner handling of long names
allow incomplete imports of filenames
struct filename ->refcnt doesn't need to be atomic
allow to use CLASS() for struct filename *
file_getattr(): filename_lookup() accepts ERR_PTR() as filename
file_setattr(): filename_lookup() accepts ERR_PTR() as filename
move_mount(): filename_lookup() accepts ERR_PTR() as filename
ksmbd_vfs_path_lookup(): vfs_path_parent_lookup() accepts ERR_PTR() as name
ksmbd_vfs_rename(): vfs_path_parent_lookup() accepts ERR_PTR() as name
do_filp_open(): DTRT when getting ERR_PTR() as pathname
rename do_filp_open() to do_file_open()
do_sys_openat2(): get rid of useless check, switch to CLASS(filename)
simplify the callers of file_open_name()
simplify the callers of do_open_execat()
simplify the callers of alloc_bprm()
switch {alloc,free}_bprm() to CLASS()
file_[gs]etattr(2): switch to CLASS(filename_maybe_null)
mount_setattr(2): don't mess with LOOKUP_EMPTY
do_open_execat(): don't care about LOOKUP_EMPTY
vfs_open_tree(): use CLASS(filename_uflags)
name_to_handle_at(): use CLASS(filename_uflags)
fspick(2): use CLASS(filename_flags)
do_fchownat(): unspaghettify a bit...
chdir(2): unspaghettify a bit...
do_utimes_path(): switch to CLASS(filename_uflags)
do_sys_truncate(): switch to CLASS(filename)
do_readlinkat(): switch to CLASS(filename_flags)
do_f{chmod,chown,access}at(): use CLASS(filename_uflags)
io_openat2(): use CLASS(filename_complete_delayed)
io_statx(): use CLASS(filename_complete_delayed)
do_{renameat2,linkat,symlinkat}(): use CLASS(filename_consume)
do_{mknodat,mkdirat,unlinkat,rmdir}(): use CLASS(filename_consume)
namei.c: convert getname_kernel() callers to CLASS(filename_kernel)
namei.c: switch user pathname imports to CLASS(filename{,_flags})
filename_...xattr(): don't consume filename reference
move_mount(2): switch to CLASS(filename_maybe_null)
chroot(2): switch to CLASS(filename)
quotactl_block(): switch to CLASS(filename)
statx: switch to CLASS(filename_maybe_null)
user_statfs(): switch to CLASS(filename)
mqueue: switch to CLASS(filename)
ksmbd: use CLASS(filename_kernel)
alpha: switch osf_mount() to strndup_user()
sysfs(2): fs_index() argument is _not_ a pathname
Mateusz Guzik (1):
fs: hide names_cache behind runtime const machinery
Diffstat:
arch/alpha/kernel/osf_sys.c | 34 +--
fs/dcache.c | 8 +-
fs/exec.c | 99 +++-----
fs/fhandle.c | 5 +-
fs/file_attr.c | 12 +-
fs/filesystems.c | 9 +-
fs/fsopen.c | 6 +-
fs/internal.h | 4 +-
fs/namei.c | 359 ++++++++++++++++--------------
fs/namespace.c | 22 +-
fs/ntfs3/inode.c | 6 +-
fs/ntfs3/namei.c | 8 +-
fs/open.c | 119 ++++------
fs/quota/quota.c | 3 +-
fs/smb/server/vfs.c | 15 +-
fs/stat.c | 28 +--
fs/statfs.c | 3 +-
fs/utimes.c | 8 +-
fs/xattr.c | 33 +--
include/asm-generic/vmlinux.lds.h | 3 +-
include/linux/audit.h | 11 -
include/linux/fs.h | 42 ++--
io_uring/fs.c | 101 +++++----
io_uring/openclose.c | 26 +--
io_uring/statx.c | 17 +-
io_uring/xattr.c | 30 +--
ipc/mqueue.c | 11 +-
kernel/acct.c | 4 +-
kernel/auditsc.c | 23 +-
mm/huge_memory.c | 15 +-
mm/swapfile.c | 21 +-
31 files changed, 459 insertions(+), 626 deletions(-)
Rough overview:
1--9:
moving pathname import out of retry loops
10:
now we can get rid of "reuse the struct filename if
we'd just imported it from the same address _and_ audit is
enabled" logics.
11:
get rid of names_cachep abuse in ntfs
12--15:
embed reasonably short pathnames into struct filename,
*always* get struct filename out names_cachep, take the long
names into explicitly kmalloc'ed objects.
NB: EMBEDDED_NAME_MAX is 128 at the moment; might make sense
to increase it - the nearest kmalloc cache size is 192 bytes,
so we are leaving gaps anyway. 40 bytes increase, at least?
More on 32bit...
16:
runtime_const machinery for names_cachep; there's
a potentially better variant (statically allocated kmem_cache),
but that's a separate series.
17:
delayed_filename machinery, solves the audit vs. io_uring
problems.
18:
now we don't need filename->refcnt to be atomic.
19:
infrastructure for CLASS(filename...)
20--24:
simplify checks in callers of pathwalk primitives -
they (with exception of do_filp_open()) will do
the right thing if given ERR_PTR() for name.
25--31: ... get rid of that one exception and simplify
more callers.
32--57:
conversions to CLASS(filename...), cleanups
58, 59:
... and these should not have been using getname().
--
2.47.3