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From: Gabriel Krisman Bertazi <krisman@collabora.com>
To: jack@suse.com, amir73il@gmail.com
Cc: djwong@kernel.org, tytso@mit.edu, dhowells@redhat.com,
	khazhy@google.com, linux-fsdevel@vger.kernel.org,
	linux-ext4@vger.kernel.org, linux-api@vger.kernel.org,
	repnop@google.com, kernel@collabora.com,
	Gabriel Krisman Bertazi <krisman@collabora.com>
Subject: [PATCH v7 03/28] fsnotify: clarify contract for create event hooks
Date: Thu, 14 Oct 2021 18:36:21 -0300	[thread overview]
Message-ID: <20211014213646.1139469-4-krisman@collabora.com> (raw)
In-Reply-To: <20211014213646.1139469-1-krisman@collabora.com>

From: Amir Goldstein <amir73il@gmail.com>

Clarify argument names and contract for fsnotify_create() and
fsnotify_mkdir() to reflect the anomaly of kernfs, which leaves dentries
negavite after mkdir/create.

Remove the WARN_ON(!inode) in audit code that were added by the Fixes
commit under the wrong assumption that dentries cannot be negative after
mkdir/create.

Fixes: aa93bdc5500c ("fsnotify: use helpers to access data by data_type")
Link: https://lore.kernel.org/linux-fsdevel/87mtp5yz0q.fsf@collabora.com/
Reported-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
---
 include/linux/fsnotify.h | 22 ++++++++++++++++------
 kernel/audit_fsnotify.c  |  3 +--
 kernel/audit_watch.c     |  3 +--
 3 files changed, 18 insertions(+), 10 deletions(-)

diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h
index df0fa4687a18..1e5f7435a4b5 100644
--- a/include/linux/fsnotify.h
+++ b/include/linux/fsnotify.h
@@ -192,16 +192,22 @@ static inline void fsnotify_inoderemove(struct inode *inode)
 
 /*
  * fsnotify_create - 'name' was linked in
+ *
+ * Caller must make sure that dentry->d_name is stable.
+ * Note: some filesystems (e.g. kernfs) leave @dentry negative and instantiate
+ * ->d_inode later
  */
-static inline void fsnotify_create(struct inode *inode, struct dentry *dentry)
+static inline void fsnotify_create(struct inode *dir, struct dentry *dentry)
 {
-	audit_inode_child(inode, dentry, AUDIT_TYPE_CHILD_CREATE);
+	audit_inode_child(dir, dentry, AUDIT_TYPE_CHILD_CREATE);
 
-	fsnotify_dirent(inode, dentry, FS_CREATE);
+	fsnotify_dirent(dir, dentry, FS_CREATE);
 }
 
 /*
  * fsnotify_link - new hardlink in 'inode' directory
+ *
+ * Caller must make sure that new_dentry->d_name is stable.
  * Note: We have to pass also the linked inode ptr as some filesystems leave
  *   new_dentry->d_inode NULL and instantiate inode pointer later
  */
@@ -230,12 +236,16 @@ static inline void fsnotify_unlink(struct inode *dir, struct dentry *dentry)
 
 /*
  * fsnotify_mkdir - directory 'name' was created
+ *
+ * Caller must make sure that dentry->d_name is stable.
+ * Note: some filesystems (e.g. kernfs) leave @dentry negative and instantiate
+ * ->d_inode later
  */
-static inline void fsnotify_mkdir(struct inode *inode, struct dentry *dentry)
+static inline void fsnotify_mkdir(struct inode *dir, struct dentry *dentry)
 {
-	audit_inode_child(inode, dentry, AUDIT_TYPE_CHILD_CREATE);
+	audit_inode_child(dir, dentry, AUDIT_TYPE_CHILD_CREATE);
 
-	fsnotify_dirent(inode, dentry, FS_CREATE | FS_ISDIR);
+	fsnotify_dirent(dir, dentry, FS_CREATE | FS_ISDIR);
 }
 
 /*
diff --git a/kernel/audit_fsnotify.c b/kernel/audit_fsnotify.c
index 60739d5e3373..02348b48447c 100644
--- a/kernel/audit_fsnotify.c
+++ b/kernel/audit_fsnotify.c
@@ -160,8 +160,7 @@ static int audit_mark_handle_event(struct fsnotify_mark *inode_mark, u32 mask,
 
 	audit_mark = container_of(inode_mark, struct audit_fsnotify_mark, mark);
 
-	if (WARN_ON_ONCE(inode_mark->group != audit_fsnotify_group) ||
-	    WARN_ON_ONCE(!inode))
+	if (WARN_ON_ONCE(inode_mark->group != audit_fsnotify_group))
 		return 0;
 
 	if (mask & (FS_CREATE|FS_MOVED_TO|FS_DELETE|FS_MOVED_FROM)) {
diff --git a/kernel/audit_watch.c b/kernel/audit_watch.c
index 2acf7ca49154..223eed7b39cd 100644
--- a/kernel/audit_watch.c
+++ b/kernel/audit_watch.c
@@ -472,8 +472,7 @@ static int audit_watch_handle_event(struct fsnotify_mark *inode_mark, u32 mask,
 
 	parent = container_of(inode_mark, struct audit_parent, mark);
 
-	if (WARN_ON_ONCE(inode_mark->group != audit_watch_group) ||
-	    WARN_ON_ONCE(!inode))
+	if (WARN_ON_ONCE(inode_mark->group != audit_watch_group))
 		return 0;
 
 	if (mask & (FS_CREATE|FS_MOVED_TO) && inode)
-- 
2.33.0


  parent reply	other threads:[~2021-10-14 21:37 UTC|newest]

Thread overview: 67+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-14 21:36 [PATCH v7 00/28] file system-wide error monitoring Gabriel Krisman Bertazi
2021-10-14 21:36 ` [PATCH v7 01/28] fsnotify: pass data_type to fsnotify_name() Gabriel Krisman Bertazi
2021-10-15  9:18   ` Jan Kara
2021-10-14 21:36 ` [PATCH v7 02/28] fsnotify: pass dentry instead of inode data Gabriel Krisman Bertazi
2021-10-15 13:39   ` Jan Kara
2021-10-18  9:11   ` Jan Kara
2021-10-14 21:36 ` Gabriel Krisman Bertazi [this message]
2021-10-15  9:21   ` [PATCH v7 03/28] fsnotify: clarify contract for create event hooks Jan Kara
2021-10-14 21:36 ` [PATCH v7 04/28] fsnotify: Don't insert unmergeable events in hashtable Gabriel Krisman Bertazi
2021-10-14 21:36 ` [PATCH v7 05/28] fanotify: Fold event size calculation to its own function Gabriel Krisman Bertazi
2021-10-14 21:36 ` [PATCH v7 06/28] fanotify: Split fsid check from other fid mode checks Gabriel Krisman Bertazi
2021-10-14 21:36 ` [PATCH v7 07/28] inotify: Don't force FS_IN_IGNORED Gabriel Krisman Bertazi
2021-10-14 21:36 ` [PATCH v7 08/28] fsnotify: Add helper to detect overflow_event Gabriel Krisman Bertazi
2021-10-14 21:36 ` [PATCH v7 09/28] fsnotify: Add wrapper around fsnotify_add_event Gabriel Krisman Bertazi
2021-10-14 21:36 ` [PATCH v7 10/28] fsnotify: Retrieve super block from the data field Gabriel Krisman Bertazi
2021-10-15  5:39   ` Amir Goldstein
2021-10-15  9:26   ` Jan Kara
2021-10-14 21:36 ` [PATCH v7 11/28] fsnotify: Pass group argument to free_event Gabriel Krisman Bertazi
2021-10-15  5:40   ` Amir Goldstein
2021-10-15  9:26   ` Jan Kara
2021-10-14 21:36 ` [PATCH v7 12/28] fanotify: Support null inode event in fanotify_dfid_inode Gabriel Krisman Bertazi
2021-10-15  5:49   ` Amir Goldstein
2021-10-15  9:30   ` Jan Kara
2021-10-14 21:36 ` [PATCH v7 13/28] fanotify: Allow file handle encoding for unhashed events Gabriel Krisman Bertazi
2021-10-14 21:36 ` [PATCH v7 14/28] fanotify: Encode empty file handle when no inode is provided Gabriel Krisman Bertazi
2021-10-15  6:02   ` Amir Goldstein
2021-10-15  9:32   ` Jan Kara
2021-10-14 21:36 ` [PATCH v7 15/28] fanotify: Require fid_mode for any non-fd event Gabriel Krisman Bertazi
2021-10-14 21:36 ` [PATCH v7 16/28] fsnotify: Support FS_ERROR event type Gabriel Krisman Bertazi
2021-10-14 21:36 ` [PATCH v7 17/28] fanotify: Reserve UAPI bits for FAN_FS_ERROR Gabriel Krisman Bertazi
2021-10-15  9:37   ` Jan Kara
2021-10-14 21:36 ` [PATCH v7 18/28] fanotify: Pre-allocate pool of error events Gabriel Krisman Bertazi
2021-10-15  6:19   ` Amir Goldstein
2021-10-15  7:33     ` Amir Goldstein
2021-10-15  9:46   ` Jan Kara
2021-10-14 21:36 ` [PATCH v7 19/28] fanotify: Limit number of marks with FAN_FS_ERROR per group Gabriel Krisman Bertazi
2021-10-15  6:15   ` Amir Goldstein
2021-10-15 16:53     ` Gabriel Krisman Bertazi
2021-10-15 17:49       ` Amir Goldstein
2021-10-14 21:36 ` [PATCH v7 20/28] fanotify: Support enqueueing of error events Gabriel Krisman Bertazi
2021-10-15  7:04   ` Amir Goldstein
2021-10-15 16:50     ` Gabriel Krisman Bertazi
2021-10-15 12:34   ` Jan Kara
2021-10-14 21:36 ` [PATCH v7 21/28] fanotify: Support merging " Gabriel Krisman Bertazi
2021-10-15  7:09   ` Amir Goldstein
2021-10-15 16:54     ` Gabriel Krisman Bertazi
2021-10-15 17:52       ` Amir Goldstein
2021-10-18 13:55         ` Gabriel Krisman Bertazi
2021-10-15 12:43   ` Jan Kara
2021-10-14 21:36 ` [PATCH v7 22/28] fanotify: Report FID entry even for zero-length file_handle Gabriel Krisman Bertazi
2021-10-15  8:10   ` Amir Goldstein
2021-10-15 13:13     ` Jan Kara
2021-10-14 21:36 ` [PATCH v7 23/28] fanotify: Report fid info for file related file system errors Gabriel Krisman Bertazi
2021-10-15  7:56   ` Amir Goldstein
2021-10-15 13:38     ` Jan Kara
2021-10-14 21:36 ` [PATCH v7 24/28] fanotify: Emit generic error info for error event Gabriel Krisman Bertazi
2021-10-15  8:13   ` Amir Goldstein
2021-10-15 12:47   ` Jan Kara
2021-10-14 21:36 ` [PATCH v7 25/28] fanotify: Allow users to request FAN_FS_ERROR events Gabriel Krisman Bertazi
2021-10-15  8:27   ` Amir Goldstein
2021-10-15 12:49   ` Jan Kara
2021-10-14 21:36 ` [PATCH v7 26/28] ext4: Send notifications on error Gabriel Krisman Bertazi
2021-10-14 21:59   ` Theodore Ts'o
2021-10-14 21:36 ` [PATCH v7 27/28] samples: Add fs error monitoring example Gabriel Krisman Bertazi
2021-10-14 21:36 ` [PATCH v7 28/28] docs: Document the FAN_FS_ERROR event Gabriel Krisman Bertazi
2021-10-15  8:38 ` [PATCH v7 00/28] file system-wide error monitoring Amir Goldstein
2021-10-15  9:16 ` Jan Kara

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