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David Howells b74c02a379 afs: Fix occasional rmdir-then-VNOVNODE with generic/011
Sometimes generic/011 causes kafs to follow up an FS.RemoveDir RPC call by
spending around a second sending a slew of FS.FetchStatus RPC calls to the
directory just deleted that then abort with VNOVNODE, indicating deletion
of the target directory.

This seems to stem from userspace attempting to stat the directory or
something in it:

    afs_select_fileserver+0x46d/0xaa2
    afs_wait_for_operation+0x12/0x17e
    afs_fetch_status+0x56/0x75
    afs_validate+0xfb/0x240
    afs_permission+0xef/0x1b0
    inode_permission+0x90/0x139
    link_path_walk.part.0.constprop.0+0x6f/0x2f0
    path_lookupat+0x4c/0xfa
    filename_lookup+0x63/0xd7
    vfs_statx+0x62/0x13f
    vfs_fstatat+0x72/0x8a

The issue appears to be that afs_dir_remove_subdir() marks the callback
promise as being cancelled by setting the expiry time to AFS_NO_CB_PROMISE
- which then confuses afs_validate() which sends the FetchStatus to try and
get a new one before it checks for the AFS_VNODE_DELETED flag which
indicates that we know the directory got deleted.

Fix this by:

 (1) Make afs_check_validity() return true if AFS_VNODE_DELETED is set, and
     then tweak the return from afs_validate() if the DELETED flag is set.

 (2) Move the AFS_VNODE_DELETED check in afs_validate() up above the
     expiration check to immediately after we've grabbed the validate_lock.

Fixes: 453924de62 ("afs: Overhaul invalidation handling to better support RO volumes")
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/20240313081505.3060173-3-dhowells@redhat.com
Reviewed-by: Marc Dionne <marc.dionne@auristor.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-03-14 12:13:21 +01:00
Documentation drm for 6.9: 2024-03-13 18:34:05 -07:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
arch drm for 6.9: 2024-03-13 18:34:05 -07:00
block Revert "dm: use queue_limits_set" 2024-03-11 17:11:28 -07:00
certs This update includes the following changes: 2023-11-02 16:15:30 -10:00
crypto crypto: lskcipher - Copy IV in lskcipher glue code always 2024-02-24 08:37:24 +08:00
drivers drm for 6.9: 2024-03-13 18:34:05 -07:00
fs afs: Fix occasional rmdir-then-VNOVNODE with generic/011 2024-03-14 12:13:21 +01:00
include drm for 6.9: 2024-03-13 18:34:05 -07:00
init Modules changes for v6.9-rc1 2024-03-13 12:40:58 -07:00
io_uring for-6.9/io_uring-20240310 2024-03-11 11:35:31 -07:00
ipc shm: Slim down dependencies 2023-12-20 19:26:31 -05:00
kernel pidfs: remove config option 2024-03-13 12:53:53 -07:00
lib Modules changes for v6.9-rc1 2024-03-13 12:40:58 -07:00
mm \n 2024-03-13 14:30:58 -07:00
net mm, slab: remove last vestiges of SLAB_MEM_SPREAD 2024-03-12 20:32:19 -07:00
rust Networking changes for 6.9. 2024-03-12 17:44:08 -07:00
samples Networking changes for 6.9. 2024-03-12 17:44:08 -07:00
scripts New code for 6.9: 2024-03-13 13:52:24 -07:00
security lsm/stable-6.9 PR 20240312 2024-03-12 20:03:34 -07:00
sound Power management updates for 6.9-rc1 2024-03-13 11:40:06 -07:00
tools drm for 6.9: 2024-03-13 18:34:05 -07:00
usr Kbuild updates for v6.8 2024-01-18 17:57:07 -08:00
virt KVM: Make KVM_MEM_GUEST_MEMFD mutually exclusive with KVM_MEM_READONLY 2024-02-22 17:07:06 -08:00
.clang-format clang-format: Update with v6.7-rc4's `for_each` macro list 2023-12-08 23:54:38 +01:00
.cocciconfig
.editorconfig Add .editorconfig file for basic formatting 2023-12-28 16:22:47 +09:00
.get_maintainer.ignore Add Jeff Kirsher to .get_maintainer.ignore 2024-03-08 11:36:54 +00:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore Add .editorconfig file for basic formatting 2023-12-28 16:22:47 +09:00
.mailmap Networking changes for 6.9. 2024-03-12 17:44:08 -07:00
.rustfmt.toml
COPYING
CREDITS vfs-6.9.ntfs 2024-03-11 09:55:17 -07:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig
MAINTAINERS drm for 6.9: 2024-03-13 18:34:05 -07:00
Makefile Rust changes for v6.9 2024-03-11 12:31:28 -07:00
README README: Fix spelling/capitalization 2024-02-12 16:42:13 -07:00

README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the ReStructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.