This is a note to let you know that I've just added the patch titled
eventfs: Clean up dentry ops and add revalidate function
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
eventfs-clean-up-dentry-ops-and-add-revalidate-function.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From SRS0=eEWY=JP=rostedt.homelinux.com=rostedt@xxxxxxxxxx Tue Feb 6 13:11:35 2024
From: Steven Rostedt <rostedt@xxxxxxxxxxx>
Date: Tue, 06 Feb 2024 07:09:57 -0500
Subject: eventfs: Clean up dentry ops and add revalidate function
To: linux-kernel@xxxxxxxxxxxxxxx, stable@xxxxxxxxxxxxxxx
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>, Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>, Sasha Levin <sashal@xxxxxxxxxx>, Masami Hiramatsu <mhiramat@xxxxxxxxxx>, Mark Rutland <mark.rutland@xxxxxxx>, Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>, Christian Brauner <brauner@xxxxxxxxxx>, Al Viro <viro@xxxxxxxxxxxxxxxxxx>, Ajay Kaher <ajay.kaher@xxxxxxxxxxxx>
Message-ID: <20240206120954.845943821@xxxxxxxxxxxxxxxxxxxxx>
From: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
commit 8dce06e98c70a7fcbb4bca7d90faf40522e65c58 upstream.
In order for the dentries to stay up-to-date with the eventfs changes,
just add a 'd_revalidate' function that checks the 'is_freed' bit.
Also, clean up the dentry release to actually use d_release() rather
than the slightly odd d_iput() function. We don't care about the inode,
all we want to do is to get rid of the refcount to the eventfs data
added by dentry->d_fsdata.
It would probably be cleaner to make eventfs its own filesystem, or at
least set its own dentry ops when looking up eventfs files. But as it
is, only eventfs dentries use d_fsdata, so we don't really need to split
these things up by use.
Another thing that might be worth doing is to make all eventfs lookups
mark their dentries as not worth caching. We could do that with
d_delete(), but the DCACHE_DONTCACHE flag would likely be even better.
As it is, the dentries are all freeable, but they only tend to get freed
at memory pressure rather than more proactively. But that's a separate
issue.
Link: https://lore.kernel.org/linux-trace-kernel/202401291043.e62e89dc-oliver.sang@xxxxxxxxx/
Link: https://lore.kernel.org/linux-trace-kernel/20240131185513.124644253@xxxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx
Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
Cc: Christian Brauner <brauner@xxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Ajay Kaher <ajay.kaher@xxxxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Fixes: c1504e510238 ("eventfs: Implement eventfs dir creation functions")
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/tracefs/event_inode.c | 5 ++---
fs/tracefs/inode.c | 27 ++++++++++++++++++---------
fs/tracefs/internal.h | 3 ++-
3 files changed, 22 insertions(+), 13 deletions(-)
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -378,13 +378,12 @@ static void free_ei(struct eventfs_inode
}
/**
- * eventfs_set_ei_status_free - remove the dentry reference from an eventfs_inode
- * @ti: the tracefs_inode of the dentry
+ * eventfs_d_release - dentry is going away
* @dentry: dentry which has the reference to remove.
*
* Remove the association between a dentry from an eventfs_inode.
*/
-void eventfs_set_ei_status_free(struct tracefs_inode *ti, struct dentry *dentry)
+void eventfs_d_release(struct dentry *dentry)
{
struct eventfs_inode *ei;
int i;
--- a/fs/tracefs/inode.c
+++ b/fs/tracefs/inode.c
@@ -377,21 +377,30 @@ static const struct super_operations tra
.show_options = tracefs_show_options,
};
-static void tracefs_dentry_iput(struct dentry *dentry, struct inode *inode)
+/*
+ * It would be cleaner if eventfs had its own dentry ops.
+ *
+ * Note that d_revalidate is called potentially under RCU,
+ * so it can't take the eventfs mutex etc. It's fine - if
+ * we open a file just as it's marked dead, things will
+ * still work just fine, and just see the old stale case.
+ */
+static void tracefs_d_release(struct dentry *dentry)
{
- struct tracefs_inode *ti;
+ if (dentry->d_fsdata)
+ eventfs_d_release(dentry);
+}
- if (!dentry || !inode)
- return;
+static int tracefs_d_revalidate(struct dentry *dentry, unsigned int flags)
+{
+ struct eventfs_inode *ei = dentry->d_fsdata;
- ti = get_tracefs(inode);
- if (ti && ti->flags & TRACEFS_EVENT_INODE)
- eventfs_set_ei_status_free(ti, dentry);
- iput(inode);
+ return !(ei && ei->is_freed);
}
static const struct dentry_operations tracefs_dentry_operations = {
- .d_iput = tracefs_dentry_iput,
+ .d_revalidate = tracefs_d_revalidate,
+ .d_release = tracefs_d_release,
};
static int trace_fill_super(struct super_block *sb, void *data, int silent)
--- a/fs/tracefs/internal.h
+++ b/fs/tracefs/internal.h
@@ -78,6 +78,7 @@ struct dentry *tracefs_start_creating(co
struct dentry *tracefs_end_creating(struct dentry *dentry);
struct dentry *tracefs_failed_creating(struct dentry *dentry);
struct inode *tracefs_get_inode(struct super_block *sb);
-void eventfs_set_ei_status_free(struct tracefs_inode *ti, struct dentry *dentry);
+
+void eventfs_d_release(struct dentry *dentry);
#endif /* _TRACEFS_INTERNAL_H */
Patches currently in stable-queue which might be from rostedt@xxxxxxxxxx are
queue-6.6/eventfs-keep-all-directory-links-at-1.patch
queue-6.6/eventfs-make-sure-that-parent-d_inode-is-locked-in-creating-files-dirs.patch
queue-6.6/eventfs-save-directory-inodes-in-the-eventfs_inode-structure.patch
queue-6.6/revert-eventfs-save-ownership-and-mode.patch
queue-6.6/tracefs-zero-out-the-tracefs_inode-when-allocating-it.patch
queue-6.6/eventfs-read-ei-entries-before-ei-children-in-eventfs_iterate.patch
queue-6.6/eventfs-do-not-invalidate-dentry-in-create_file-dir_dentry.patch
queue-6.6/eventfs-fix-file-and-directory-uid-and-gid-ownership.patch
queue-6.6/eventfs-remove-lookup-parameter-from-create_dir-file_dentry.patch
queue-6.6/eventfs-use-gfp_nofs-for-allocation-when-eventfs_mutex-is-held.patch
queue-6.6/eventfs-remove-fsnotify-functions-from-lookup.patch
queue-6.6/eventfs-use-err_cast-in-eventfs_create_events_dir.patch
queue-6.6/revert-eventfs-use-simple_recursive_removal-to-clean-up-dentries.patch
queue-6.6/eventfs-use-simple_recursive_removal-to-clean-up-dentries.patch
queue-6.6/eventfs-stop-using-dcache_readdir-for-getdents.patch
queue-6.6/eventfs-have-event-files-and-directories-default-to-parent-uid-and-gid.patch
queue-6.6/eventfs-use-eventfs_remove_events_dir.patch
queue-6.6/eventfs-delete-eventfs_inode-when-the-last-dentry-is-freed.patch
queue-6.6/tracefs-avoid-using-the-ei-dentry-pointer-unnecessarily.patch
queue-6.6/tracefs-remove-stale-update_gid-code.patch
queue-6.6/eventfs-initialize-the-tracefs-inode-properly.patch
queue-6.6/eventfs-remove-special-processing-of-dput-of-events-directory.patch
queue-6.6/eventfs-save-ownership-and-mode.patch
queue-6.6/tracefs-check-for-dentry-d_inode-exists-in-set_gid.patch
queue-6.6/eventfs-do-ctx-pos-update-for-all-iterations-in-eventfs_iterate.patch
queue-6.6/tracefs-dentry-lookup-crapectomy.patch
queue-6.6/eventfs-move-taking-of-inode_lock-into-dcache_dir_open_wrapper.patch
queue-6.6/eventfs-have-a-free_ei-that-just-frees-the-eventfs_inode.patch
queue-6.6/revert-eventfs-remove-is_freed-union-with-rcu-head.patch
queue-6.6/eventfs-have-the-inodes-all-for-files-and-directories-all-be-the-same.patch
queue-6.6/eventfs-use-kcalloc-instead-of-kzalloc.patch
queue-6.6/eventfs-test-for-ei-is_freed-when-accessing-ei-dentry.patch
queue-6.6/eventfs-fix-bitwise-fields-for-is_events.patch
queue-6.6/eventfs-fix-warn_on-in-create_file_dentry.patch
queue-6.6/eventfs-fix-events-beyond-name_max-blocking-tasks.patch
queue-6.6/eventfs-shortcut-eventfs_iterate-by-skipping-entries-already-read.patch
queue-6.6/revert-eventfs-do-not-allow-null-parent-to-eventfs_start_creating.patch
queue-6.6/eventfs-do-not-allow-null-parent-to-eventfs_start_creating.patch
queue-6.6/eventfs-do-not-create-dentries-nor-inodes-in-iterate_shared.patch
queue-6.6/eventfs-have-eventfs_iterate-stop-immediately-if-ei-is_freed-is-set.patch
queue-6.6/eventfs-fix-typo-in-eventfs_inode-union-comment.patch
queue-6.6/eventfs-remove-expectation-that-ei-is_freed-means-ei-dentry-null.patch
queue-6.6/eventfs-restructure-eventfs_inode-structure-to-be-more-condensed.patch
queue-6.6/eventfs-warn-if-an-eventfs_inode-is-freed-without-is_freed-being-set.patch
queue-6.6/eventfs-get-rid-of-dentry-pointers-without-refcounts.patch
queue-6.6/eventfs-remove-unused-d_parent-pointer-field.patch
queue-6.6/eventfs-hold-eventfs_mutex-when-calling-callback-functions.patch
queue-6.6/eventfs-remove-is_freed-union-with-rcu-head.patch
queue-6.6/tracefs-eventfs-modify-mismatched-function-name.patch
queue-6.6/eventfs-fix-kerneldoc-of-eventfs_remove_rec.patch
queue-6.6/tracefs-eventfs-use-root-and-instance-inodes-as-default-ownership.patch
queue-6.6/revert-eventfs-check-for-null-ef-in-eventfs_set_attr.patch
queue-6.6/eventfs-fix-failure-path-in-eventfs_create_events_dir.patch
queue-6.6/eventfs-clean-up-dentry-ops-and-add-revalidate-function.patch
