linux/fs
Linus Torvalds 43aa6f97c2 eventfs: Get rid of dentry pointers without refcounts
The eventfs inode had pointers to dentries (and child dentries) without
actually holding a refcount on said pointer.  That is fundamentally
broken, and while eventfs tried to then maintain coherence with dentries
going away by hooking into the '.d_iput' callback, that doesn't actually
work since it's not ordered wrt lookups.

There were two reasonms why eventfs tried to keep a pointer to a dentry:

 - the creation of a 'events' directory would actually have a stable
   dentry pointer that it created with tracefs_start_creating().

   And it needed that dentry when tearing it all down again in
   eventfs_remove_events_dir().

   This use is actually ok, because the special top-level events
   directory dentries are actually stable, not just a temporary cache of
   the eventfs data structures.

 - the 'eventfs_inode' (aka ei) needs to stay around as long as there
   are dentries that refer to it.

   It then used these dentry pointers as a replacement for doing
   reference counting: it would try to make sure that there was only
   ever one dentry associated with an event_inode, and keep a child
   dentry array around to see which dentries might still refer to the
   parent ei.

This gets rid of the invalid dentry pointer use, and renames the one
valid case to a different name to make it clear that it's not just any
random dentry.

The magic child dentry array that is kind of a "reverse reference list"
is simply replaced by having child dentries take a ref to the ei.  As
does the directory dentries.  That makes the broken use case go away.

Link: https://lore.kernel.org/linux-trace-kernel/202401291043.e62e89dc-oliver.sang@intel.com/
Link: https://lore.kernel.org/linux-trace-kernel/20240131185513.280463000@goodmis.org

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Ajay Kaher <ajay.kaher@broadcom.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fixes: c1504e5102 ("eventfs: Implement eventfs dir creation functions")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-02-01 10:31:17 -05:00
..
9p 9p: Use length of data written to the server in preference to error 2024-01-04 13:15:31 +00:00
adfs adfs: remove writepage implementation 2023-12-29 11:58:33 -08:00
affs affs: d_obtain_alias(ERR_PTR(...)) will do the right thing 2023-12-21 12:51:02 -05:00
afs vfs-6.8.netfs 2024-01-19 09:10:23 -08:00
autofs dcache stuff for this cycle 2024-01-11 20:11:35 -08:00
bcachefs More bcachefs updates for 6.7-rc1 2024-01-21 14:01:12 -08:00
befs befs: d_obtain_alias(ERR_PTR(...)) will do the right thing 2023-12-21 12:51:02 -05:00
bfs misc cleanups (the part that hadn't been picked by individual fs trees) 2024-01-11 20:23:50 -08:00
btrfs for-6.8/block-2024-01-08 2024-01-11 13:58:04 -08:00
cachefiles vfs-6.8.netfs 2024-01-19 09:10:23 -08:00
ceph Assorted CephFS fixes and cleanups with nothing standing out. 2024-01-19 09:58:55 -08:00
coda dcache stuff for this cycle 2024-01-11 20:11:35 -08:00
configfs
cramfs vfs-6.7.ctime 2023-10-30 09:47:13 -10:00
crypto fscrypt: document that CephFS supports fscrypt now 2023-12-26 22:55:42 -06:00
debugfs Merge branches 'acpi-pm', 'acpi-video', 'acpi-apei' and 'acpi-extlog' 2024-01-04 13:19:40 +01:00
devpts fs: Remove the now superfluous sentinel elements from ctl_table array 2023-12-28 04:57:57 -08:00
dlm dlm: update format header reflect current format 2023-12-20 15:36:48 -06:00
ecryptfs fix directory locking scheme on rename 2024-01-11 20:00:22 -08:00
efivarfs efivarfs: automatically update super block flag 2023-12-11 11:19:18 +01:00
efs vfs-6.7.fsid 2023-11-07 12:11:26 -08:00
erofs vfs-6.8.netfs 2024-01-19 09:10:23 -08:00
exfat exfat: do not zero the extended part 2024-01-08 21:57:22 +09:00
exportfs fs: fix build error with CONFIG_EXPORTFS=m or not defined 2023-10-28 16:16:19 +02:00
ext2 fix directory locking scheme on rename 2024-01-11 20:00:22 -08:00
ext4 misc cleanups (the part that hadn't been picked by individual fs trees) 2024-01-11 20:23:50 -08:00
f2fs f2fs: fix double free of f2fs_sb_info 2024-01-12 18:55:09 -08:00
fat vfs-6.7.fsid 2023-11-07 12:11:26 -08:00
freevxfs freevxfs: lookup: fix function params kernel-doc 2023-12-20 15:02:58 -08:00
fuse vfs-6.8.rw 2024-01-08 11:11:51 -08:00
gfs2 dlm for 6.8 2024-01-10 10:17:23 -08:00
hfs hfs: really remove hfs_writepage 2023-12-29 11:58:34 -08:00
hfsplus Many singleton patches against the MM code. The patch series which 2024-01-09 11:18:47 -08:00
hostfs hostfs: use d_splice_alias() calling conventions to simplify failure exits 2023-12-21 12:51:00 -05:00
hpfs
hugetlbfs Many singleton patches against the MM code. The patch series which 2024-01-09 11:18:47 -08:00
iomap mm: add folio_fill_tail() and use it in iomap 2023-12-10 16:51:36 -08:00
isofs
jbd2 jbd2: abort journal when detecting metadata writeback error of fs dev 2024-01-04 23:42:21 -05:00
jffs2 jffs2: mark __jffs2_dbg_superblock_counts() static 2023-12-10 17:21:43 -08:00
jfs jfs: Add missing set_freezable() for freezable kthread 2024-01-02 11:06:52 -06:00
kernfs Revert "kernfs: convert kernfs_idr_lock to an irq safe raw spinlock" 2024-01-11 11:51:27 +01:00
lockd sysctl-6.8-rc1 2024-01-10 17:44:36 -08:00
minix minixfs kmap_local_page() switchover and related fixes - very similar to sysv series. 2024-01-11 19:54:18 -08:00
netfs vfs-6.8.netfs 2024-01-19 09:10:23 -08:00
nfs vfs-6.8.netfs 2024-01-19 09:10:23 -08:00
nfs_common
nfsd misc cleanups (the part that hadn't been picked by individual fs trees) 2024-01-11 20:23:50 -08:00
nilfs2 misc cleanups (the part that hadn't been picked by individual fs trees) 2024-01-11 20:23:50 -08:00
nls
notify dcache stuff for this cycle 2024-01-11 20:11:35 -08:00
ntfs sysctl-6.8-rc1 2024-01-10 17:44:36 -08:00
ntfs3 vfs-6.7.fsid 2023-11-07 12:11:26 -08:00
ocfs2 misc cleanups (the part that hadn't been picked by individual fs trees) 2024-01-11 20:23:50 -08:00
omfs
openpromfs
orangefs orangefs: saner arguments passing in readdir guts 2023-12-21 12:53:36 -05:00
overlayfs dcache stuff for this cycle 2024-01-11 20:11:35 -08:00
proc 17 hotfixes. 10 address post-6.7 issues and the other 7 are cc:stable. 2024-01-17 09:31:36 -08:00
pstore pstore: inode: Use cleanup.h for struct pstore_private 2023-12-08 14:15:44 -08:00
qnx4 qnx4: Use get_directory_fname() in qnx4_match() 2023-12-13 11:19:18 -08:00
qnx6
quota sysctl-6.8-rc1 2024-01-10 17:44:36 -08:00
ramfs mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER 2024-01-08 15:27:15 -08:00
reiserfs misc cleanups (the part that hadn't been picked by individual fs trees) 2024-01-11 20:23:50 -08:00
romfs vfs-6.7.ctime 2023-10-30 09:47:13 -10:00
smb Various smb client fixes, including multichannel and for SMB3.1.1 POSIX extensions 2024-01-20 16:48:07 -08:00
squashfs Squashfs: fix variable overflow triggered by sysbot 2023-12-10 17:21:26 -08:00
sysfs fs/sysfs/dir.c : Fix typo in comment 2023-12-07 11:35:23 +09:00
sysv sysv: remove writepage implementation 2023-12-29 11:58:35 -08:00
tracefs eventfs: Get rid of dentry pointers without refcounts 2024-02-01 10:31:17 -05:00
ubifs ubifs: fix kernel-doc warnings 2024-01-06 23:49:50 +01:00
udf misc cleanups (the part that hadn't been picked by individual fs trees) 2024-01-11 20:23:50 -08:00
ufs Many singleton patches against the MM code. The patch series which 2024-01-09 11:18:47 -08:00
unicode
vboxsf fs: vboxsf: fix a kernel-doc warning 2023-12-08 15:32:31 -07:00
verity Networking changes for 6.8. 2024-01-11 10:07:29 -08:00
xfs Bug fixes for 6.8: 2024-01-19 09:57:08 -08:00
zonefs misc cleanups (the part that hadn't been picked by individual fs trees) 2024-01-11 20:23:50 -08:00
aio.c sysctl-6.8-rc1 2024-01-10 17:44:36 -08:00
anon_inodes.c Merge branch 'kvm-guestmemfd' into HEAD 2023-11-14 08:31:31 -05:00
attr.c fs: fix doc comment typo fs tree wide 2023-12-21 13:17:54 +01:00
backing-file.c fs: factor out backing_file_mmap() helper 2023-12-23 16:35:09 +02:00
bad_inode.c
binfmt_elf_fdpic.c execve updates for v6.7-rc1 2023-10-30 19:28:19 -10:00
binfmt_elf_test.c
binfmt_elf.c
binfmt_flat.c
binfmt_misc.c execve updates for v6.7-rc1 2023-10-30 19:28:19 -10:00
binfmt_script.c
buffer.c Many singleton patches against the MM code. The patch series which 2024-01-09 11:18:47 -08:00
char_dev.c As usual, lots of singleton and doubleton patches all over the tree and 2023-11-02 20:53:31 -10:00
compat_binfmt_elf.c
coredump.c fs: Remove the now superfluous sentinel elements from ctl_table array 2023-12-28 04:57:57 -08:00
d_path.c
dax.c fs : Fix warning using plain integer as NULL 2023-11-18 15:00:01 +01:00
dcache.c dcache stuff for this cycle 2024-01-11 20:11:35 -08:00
direct-io.c fs : Fix warning using plain integer as NULL 2023-11-18 15:00:01 +01:00
drop_caches.c
eventfd.c eventfd: Remove usage of the deprecated ida_simple_xx() API 2023-12-12 14:24:55 +01:00
eventpoll.c fs: Remove the now superfluous sentinel elements from ctl_table array 2023-12-28 04:57:57 -08:00
exec.c execve: open the executable file before doing anything else 2024-01-20 12:15:43 -08:00
fcntl.c
fhandle.c exportfs: add helpers to check if filesystem can encode/decode file handles 2023-10-24 17:57:45 +02:00
file_table.c dcache stuff for this cycle 2024-01-11 20:11:35 -08:00
file.c file: remove __receive_fd() 2023-12-12 14:24:14 +01:00
filesystems.c
fs_context.c
fs_parser.c
fs_pin.c
fs_struct.c
fs_types.c
fs-writeback.c netfs: Move pinning-for-writeback from fscache to netfs 2023-12-24 15:08:49 +00:00
fsopen.c
init.c
inode.c fix directory locking scheme on rename 2024-01-11 20:00:22 -08:00
internal.h dcache stuff for this cycle 2024-01-11 20:11:35 -08:00
ioctl.c lsm: new security_file_ioctl_compat() hook 2023-12-24 15:48:03 -05:00
Kconfig vfs-6.8.netfs 2024-01-19 09:10:23 -08:00
Kconfig.binfmt
kernel_read_file.c
libfs.c dcache stuff for this cycle 2024-01-11 20:11:35 -08:00
locks.c fs: Remove the now superfluous sentinel elements from ctl_table array 2023-12-28 04:57:57 -08:00
Makefile vfs-6.8.netfs 2024-01-19 09:10:23 -08:00
mbcache.c
mnt_idmapping.c mnt_idmapping: decouple from namespaces 2023-11-28 14:08:47 +01:00
mount.h mounts: keep list of mounts in an rbtree 2023-11-18 14:56:16 +01:00
mpage.c fs: convert block_write_full_page to block_write_full_folio 2023-12-29 11:58:35 -08:00
namei.c fix buggered locking in bch2_ioctl_subvolume_destroy() 2024-01-12 18:04:01 -08:00
namespace.c fs: rework listmount() implementation 2024-01-13 13:06:25 +01:00
nsfs.c nsfs: use d_make_root() 2023-11-25 02:49:43 -05:00
open.c vfs-6.8.rw 2024-01-08 11:11:51 -08:00
pipe.c sysctl-6.8-rc1 2024-01-10 17:44:36 -08:00
pnode.c mounts: keep list of mounts in an rbtree 2023-11-18 14:56:16 +01:00
pnode.h
posix_acl.c fs: fix doc comment typo fs tree wide 2023-12-21 13:17:54 +01:00
proc_namespace.c namespace: extract show_path() helper 2023-11-18 14:56:16 +01:00
read_write.c fsnotify: optionally pass access range in file permission hooks 2023-12-12 16:20:02 +01:00
readdir.c fsnotify: optionally pass access range in file permission hooks 2023-12-12 16:20:02 +01:00
remap_range.c fsnotify: optionally pass access range in file permission hooks 2023-12-12 16:20:02 +01:00
select.c
seq_file.c
signalfd.c
splice.c fs: use splice_copy_file_range() inline helper 2023-12-12 16:20:02 +01:00
stack.c
stat.c vfs-6.8.mount 2024-01-08 10:57:34 -08:00
statfs.c
super.c fscrypt updates for 6.8 2024-01-10 10:24:49 -08:00
sync.c
sysctls.c fs: Remove the now superfluous sentinel elements from ctl_table array 2023-12-28 04:57:57 -08:00
timerfd.c
userfaultfd.c Generic: 2024-01-17 13:03:37 -08:00
utimes.c
xattr.c