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From: Al Viro <[email protected]>
To: [email protected]
Cc: "Christian Brauner" <[email protected]>,
	[email protected],
	"Christian Göttsche" <[email protected]>
Subject: [RFC][PATCHES v2] xattr stuff and interactions with io_uring
Date: Sat, 2 Nov 2024 07:28:34 +0000	[thread overview]
Message-ID: <20241102072834.GQ1350452@ZenIV> (raw)
In-Reply-To: <20241002011011.GB4017910@ZenIV>

	Changes since v1:
* moved on top of (and makes use of) getname_maybe_null() stuff
(first two commits here, form #base.getname-fixed)
* fixed a leak on io_uring side spotted by Jens
* putname(ERR_PTR(-E...)) is a no-op; allows to simplify things on
io_uring side.
* applied reviewed-by
* picked a generic_listxattr() cleanup from Colin Ian King

	Help with review and testing would be welcome; if nobody objects,
to #for-next it goes...

The branch lives in
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs.git #work.xattr2
Individual patches in followups.
 
Diffstat:
 arch/alpha/kernel/syscalls/syscall.tbl      |   4 +
 arch/arm/tools/syscall.tbl                  |   4 +
 arch/m68k/kernel/syscalls/syscall.tbl       |   4 +
 arch/microblaze/kernel/syscalls/syscall.tbl |   4 +
 arch/mips/kernel/syscalls/syscall_n32.tbl   |   4 +
 arch/mips/kernel/syscalls/syscall_n64.tbl   |   4 +
 arch/mips/kernel/syscalls/syscall_o32.tbl   |   4 +
 arch/parisc/kernel/syscalls/syscall.tbl     |   4 +
 arch/powerpc/kernel/syscalls/syscall.tbl    |   4 +
 arch/s390/kernel/syscalls/syscall.tbl       |   4 +
 arch/sh/kernel/syscalls/syscall.tbl         |   4 +
 arch/sparc/kernel/syscalls/syscall.tbl      |   4 +
 arch/x86/entry/syscalls/syscall_32.tbl      |   4 +
 arch/x86/entry/syscalls/syscall_64.tbl      |   4 +
 arch/xtensa/kernel/syscalls/syscall.tbl     |   4 +
 fs/internal.h                               |  17 +-
 fs/namei.c                                  |  34 ++-
 fs/stat.c                                   |  28 +-
 fs/xattr.c                                  | 446 ++++++++++++++++++----------
 include/asm-generic/audit_change_attr.h     |   6 +
 include/linux/fs.h                          |  10 +
 include/linux/syscalls.h                    |  13 +
 include/linux/xattr.h                       |   4 +
 include/uapi/asm-generic/unistd.h           |  11 +-
 include/uapi/linux/xattr.h                  |   7 +
 io_uring/xattr.c                            |  97 ++----
 26 files changed, 466 insertions(+), 267 deletions(-)

Shortog:

Al Viro (9):
      teach filename_lookup() to treat NULL filename as ""
      getname_maybe_null() - the third variant of pathname copy-in
      io_[gs]etxattr_prep(): just use getname()
      xattr: switch to CLASS(fd)
      new helper: import_xattr_name()
      replace do_setxattr() with saner helpers.
      replace do_getxattr() with saner helpers.
      new helpers: file_listxattr(), filename_listxattr()
      new helpers: file_removexattr(), filename_removexattr()

Christian Göttsche (2):
      fs: rename struct xattr_ctx to kernel_xattr_ctx
      fs/xattr: add *at family syscalls

Colin Ian King (1):
      xattr: remove redundant check on variable err

Jens Axboe (1):
      io_uring: IORING_OP_F[GS]ETXATTR is fine with REQ_F_FIXED_FILE

Patch summaries:

getname_maybe_null() introduction (#getname.base-fixed):
01/13) teach filename_lookup() to treat NULL filename as ""
02/13) getname_maybe_null() - the third variant of pathname copy-in

io_uring-side prep:
03/13) io_uring: IORING_OP_F[GS]ETXATTR is fine with REQ_F_FIXED_FILE
04/13) io_[gs]etxattr_prep(): just use getname()
	getname_flags(_, LOOKUP_FOLLOW) is ridiculous.

05/13)	switch to CLASS(fd) use.  Obvious.

06/13)	rename struct xattr_ctx to kernel_xattr_ctx
prep from the ...xattrat() series, to reduce the PITA for rebase

07/13)	new helper: import_xattr_name()
exact same logics for copying the xattr name in, dealing with
overflows, etc. in a lot of places.  

08/13)	replace do_setxattr() with saner helpers
file_setxattr(file, ctx) and filename_setxattr(dfd, filename, lookup_flags, ctx).
Don't mess with do_setxattr() directly - use those.  In particular, don't
bother with the ESTALE loop in io_uring - it doesn't belong there.
 
09/13)	replace do_getxattr() with saner helpers
Same on getxattr() side.

10/13)	new helpers: file_listxattr(), filename_listxattr()
Same, except that io_uring doesn't use those, so the helpers are left static.

11/13)	new helpers: file_removexattr(), filename_removexattr()
Ditto

12/13)	fs/xattr: add *at family syscalls
Rebased patch introducing those, with a bunch of fixes folded in so we don't
create bisect hazard there.  Potentially interesting bit is the pathname-handling
logics - getname_maybe_null(pathname, flags) returns a struct filename reference
if no AT_EMPTY_PATH had been given or if the pathname was non-NULL and turned out
to be non-empty.  With (NULL,AT_EMPTY_PATH) or (empty string, AT_EMPTY_PATH) it
returns NULL (and it tries to skip the allocation using the same trick with
get_user() that vfs_empty_path() uses).  That helper simplifies a lot of things,
and it should be cheap enough to convert fsetxattr(2) et.al. to the unified
path_setxattrat() and its ilk.  IF we get a slowdown on those, we can always
expand and simplify the calls in fsetxattr(2) and friends.

13/13) xattr: remove redundant check on variable err

  parent reply	other threads:[~2024-11-02  7:28 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-10-02  1:10 [RFC][PATCHES] xattr stuff and interactions with io_uring Al Viro
2024-10-02  1:22 ` [PATCH 1/9] xattr: switch to CLASS(fd) Al Viro
2024-10-02  1:22   ` [PATCH 2/9] fs: rename struct xattr_ctx to kernel_xattr_ctx Al Viro
2024-10-02  5:56     ` Christian Brauner
2024-10-02  1:22   ` [PATCH 3/9] io_[gs]etxattr_prep(): just use getname() Al Viro
2024-10-02  5:57     ` Christian Brauner
2024-10-02  1:22   ` [PATCH 4/9] new helper: import_xattr_name() Al Viro
2024-10-02  5:57     ` Christian Brauner
2024-10-02  1:22   ` [PATCH 5/9] replace do_setxattr() with saner helpers Al Viro
2024-10-02  1:34     ` Jens Axboe
2024-10-02  2:08       ` Al Viro
2024-10-02 18:00         ` Jens Axboe
2024-10-02 21:19           ` Al Viro
2024-10-02 22:55             ` Jens Axboe
2024-10-06  5:28               ` Al Viro
2024-10-07 18:09                 ` Jens Axboe
2024-10-07 18:20                   ` Jens Axboe
2024-10-07 21:20                     ` Al Viro
2024-10-07 22:29                       ` Jens Axboe
2024-10-07 23:58                         ` Al Viro
2024-10-08  1:58                           ` Jens Axboe
2024-10-08  4:08                             ` Al Viro
2024-10-02  1:22   ` [PATCH 6/9] replace do_getxattr() " Al Viro
2024-10-02  5:59     ` Christian Brauner
2024-10-02  1:22   ` [PATCH 7/9] new helpers: file_listxattr(), filename_listxattr() Al Viro
2024-10-02  6:00     ` Christian Brauner
2024-10-02  1:22   ` [PATCH 8/9] new helpers: file_removexattr(), filename_removexattr() Al Viro
2024-10-02  6:01     ` Christian Brauner
2024-10-02  1:22   ` [PATCH 9/9] fs/xattr: add *at family syscalls Al Viro
2024-10-02  6:03     ` Christian Brauner
2024-10-02  5:56   ` [PATCH 1/9] xattr: switch to CLASS(fd) Christian Brauner
2024-11-02  7:28 ` Al Viro [this message]
2024-11-02  7:31   ` [PATCH v2 01/13] teach filename_lookup() to treat NULL filename as "" Al Viro
2024-11-02  7:31     ` [PATCH v2 02/13] getname_maybe_null() - the third variant of pathname copy-in Al Viro
2024-11-02  7:31     ` [PATCH v2 03/13] io_uring: IORING_OP_F[GS]ETXATTR is fine with REQ_F_FIXED_FILE Al Viro
2024-11-02  7:31     ` [PATCH v2 04/13] io_[gs]etxattr_prep(): just use getname() Al Viro
2024-11-02 14:44       ` Jens Axboe
2024-11-02  7:31     ` [PATCH v2 05/13] xattr: switch to CLASS(fd) Al Viro
2024-11-02  7:31     ` [PATCH v2 06/13] fs: rename struct xattr_ctx to kernel_xattr_ctx Al Viro
2024-11-02  7:31     ` [PATCH v2 07/13] new helper: import_xattr_name() Al Viro
2024-11-02  7:31     ` [PATCH v2 08/13] replace do_setxattr() with saner helpers Al Viro
2024-11-02  7:31     ` [PATCH v2 09/13] replace do_getxattr() " Al Viro
2024-11-02  7:31     ` [PATCH v2 10/13] new helpers: file_listxattr(), filename_listxattr() Al Viro
2024-11-02  7:31     ` [PATCH v2 11/13] new helpers: file_removexattr(), filename_removexattr() Al Viro
2024-11-02  7:31     ` [PATCH v2 12/13] fs/xattr: add *at family syscalls Al Viro
2024-11-02  7:31     ` [PATCH v2 13/13] xattr: remove redundant check on variable err Al Viro
2024-11-02 14:43   ` [RFC][PATCHES v2] xattr stuff and interactions with io_uring Jens Axboe
2024-11-03  6:51     ` Al Viro
2024-11-03 13:57       ` Arnd Bergmann
2024-11-03 18:32         ` Al Viro

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