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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, david@fromorbit.com,
	dhowells@redhat.com, khazhy@google.com,
	linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org,
	linux-api@vger.kernel.org,
	Gabriel Krisman Bertazi <krisman@collabora.com>,
	kernel@collabora.com, Jan Kara <jack@suse.cz>
Subject: [PATCH v8 15/32] fanotify: Encode empty file handle when no inode is provided
Date: Mon, 18 Oct 2021 20:59:58 -0300	[thread overview]
Message-ID: <20211019000015.1666608-16-krisman@collabora.com> (raw)
In-Reply-To: <20211019000015.1666608-1-krisman@collabora.com>

Instead of failing, encode an invalid file handle in fanotify_encode_fh
if no inode is provided.  This bogus file handle will be reported by
FAN_FS_ERROR for non-inode errors.

Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>

---
Changes since v6:
  - Use FILEID_ROOT as the internal value (jan)
  - Create an empty FH (jan)

Changes since v5:
  - Preserve flags initialization (jan)
  - Add BUILD_BUG_ON (amir)
  - Require minimum of FANOTIFY_NULL_FH_LEN for fh_len(amir)
  - Improve comment to explain the null FH length (jan)
  - Simplify logic
---
 fs/notify/fanotify/fanotify.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index ec84fee7ad01..c64d61b673ca 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -370,8 +370,14 @@ static int fanotify_encode_fh(struct fanotify_fh *fh, struct inode *inode,
 	fh->type = FILEID_ROOT;
 	fh->len = 0;
 	fh->flags = 0;
+
+	/*
+	 * Invalid FHs are used by FAN_FS_ERROR for errors not
+	 * linked to any inode. The f_handle won't be reported
+	 * back to userspace.
+	 */
 	if (!inode)
-		return 0;
+		goto out;
 
 	/*
 	 * !gpf means preallocated variable size fh, but fh_len could
@@ -403,6 +409,7 @@ static int fanotify_encode_fh(struct fanotify_fh *fh, struct inode *inode,
 	fh->type = type;
 	fh->len = fh_len;
 
+out:
 	/*
 	 * Mix fh into event merge key.  Hash might be NULL in case of
 	 * unhashed FID events (i.e. FAN_FS_ERROR).
-- 
2.33.0


  parent reply	other threads:[~2021-10-19  0:02 UTC|newest]

Thread overview: 66+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-18 23:59 [PATCH v8 00/32] file system-wide error monitoring Gabriel Krisman Bertazi
2021-10-18 23:59 ` [PATCH v8 01/32] fsnotify: pass data_type to fsnotify_name() Gabriel Krisman Bertazi
2021-10-18 23:59 ` [PATCH v8 02/32] fsnotify: pass dentry instead of inode data Gabriel Krisman Bertazi
2021-10-18 23:59 ` [PATCH v8 03/32] fsnotify: clarify contract for create event hooks Gabriel Krisman Bertazi
2021-10-18 23:59 ` [PATCH v8 04/32] fsnotify: Don't insert unmergeable events in hashtable Gabriel Krisman Bertazi
2021-10-18 23:59 ` [PATCH v8 05/32] fanotify: Fold event size calculation to its own function Gabriel Krisman Bertazi
2021-10-18 23:59 ` [PATCH v8 06/32] fanotify: Split fsid check from other fid mode checks Gabriel Krisman Bertazi
2021-10-18 23:59 ` [PATCH v8 07/32] inotify: Don't force FS_IN_IGNORED Gabriel Krisman Bertazi
2021-10-18 23:59 ` [PATCH v8 08/32] fsnotify: Add helper to detect overflow_event Gabriel Krisman Bertazi
2021-10-18 23:59 ` [PATCH v8 09/32] fsnotify: Add wrapper around fsnotify_add_event Gabriel Krisman Bertazi
2021-10-18 23:59 ` [PATCH v8 10/32] fsnotify: Retrieve super block from the data field Gabriel Krisman Bertazi
2021-10-18 23:59 ` [PATCH v8 11/32] fsnotify: Protect fsnotify_handle_inode_event from no-inode events Gabriel Krisman Bertazi
2021-10-19  5:34   ` Amir Goldstein
2021-10-19 10:01     ` Jan Kara
2021-10-18 23:59 ` [PATCH v8 12/32] fsnotify: Pass group argument to free_event Gabriel Krisman Bertazi
2021-10-18 23:59 ` [PATCH v8 13/32] fanotify: Support null inode event in fanotify_dfid_inode Gabriel Krisman Bertazi
2021-10-18 23:59 ` [PATCH v8 14/32] fanotify: Allow file handle encoding for unhashed events Gabriel Krisman Bertazi
2021-10-18 23:59 ` Gabriel Krisman Bertazi [this message]
2021-10-18 23:59 ` [PATCH v8 16/32] fanotify: Require fid_mode for any non-fd event Gabriel Krisman Bertazi
2021-10-19  0:00 ` [PATCH v8 17/32] fsnotify: Support FS_ERROR event type Gabriel Krisman Bertazi
2021-10-19  0:00 ` [PATCH v8 18/32] fanotify: Reserve UAPI bits for FAN_FS_ERROR Gabriel Krisman Bertazi
2021-10-19  0:00 ` [PATCH v8 19/32] fanotify: Pre-allocate pool of error events Gabriel Krisman Bertazi
2021-10-19  5:38   ` Amir Goldstein
2021-10-19 11:52     ` Jan Kara
2021-10-19  0:00 ` [PATCH v8 20/32] fanotify: Dynamically resize the FAN_FS_ERROR pool Gabriel Krisman Bertazi
2021-10-19  5:50   ` Amir Goldstein
2021-10-19 12:03     ` Jan Kara
2021-10-21 18:17       ` Gabriel Krisman Bertazi
2021-10-21 19:29         ` Jan Kara
2021-10-19  0:00 ` [PATCH v8 21/32] fanotify: Support enqueueing of error events Gabriel Krisman Bertazi
2021-10-19  5:52   ` Amir Goldstein
2021-10-19  0:00 ` [PATCH v8 22/32] fanotify: Support merging " Gabriel Krisman Bertazi
2021-10-19  5:56   ` Amir Goldstein
2021-10-19 13:52   ` Jan Kara
2021-10-19  0:00 ` [PATCH v8 23/32] fanotify: Wrap object_fh inline space in a creator macro Gabriel Krisman Bertazi
2021-10-19  6:09   ` Amir Goldstein
2021-10-19 13:58   ` Jan Kara
2021-10-19  0:00 ` [PATCH v8 24/32] fanotify: Add helpers to decide whether to report FID/DFID Gabriel Krisman Bertazi
2021-10-19  6:12   ` Amir Goldstein
2021-10-19 14:03   ` Jan Kara
2021-10-19  0:00 ` [PATCH v8 25/32] fanotify: Report fid entry even for zero-length file_handle Gabriel Krisman Bertazi
2021-10-19  6:13   ` Amir Goldstein
2021-10-19 14:08   ` Jan Kara
2021-10-19  0:00 ` [PATCH v8 26/32] fanotify: WARN_ON against too large file handles Gabriel Krisman Bertazi
2021-10-19  6:02   ` Amir Goldstein
2021-10-19 14:06   ` Jan Kara
2021-10-19  0:00 ` [PATCH v8 27/32] fanotify: Report fid info for file related file system errors Gabriel Krisman Bertazi
2021-10-19  6:07   ` Amir Goldstein
2021-10-19 14:41   ` Jan Kara
2021-10-19  0:00 ` [PATCH v8 28/32] fanotify: Emit generic error info for error event Gabriel Krisman Bertazi
2021-10-19  0:00 ` [PATCH v8 29/32] fanotify: Allow users to request FAN_FS_ERROR events Gabriel Krisman Bertazi
2021-10-19  5:57   ` Amir Goldstein
2021-10-19 15:24   ` Jan Kara
2021-10-19  0:00 ` [PATCH v8 30/32] ext4: Send notifications on error Gabriel Krisman Bertazi
2021-10-19 15:44   ` Jan Kara
2021-10-19 16:01     ` Jan Kara
2021-10-19 16:54       ` Gabriel Krisman Bertazi
2021-10-20  3:11         ` Theodore Ts'o
2021-10-19  0:00 ` [PATCH v8 31/32] samples: Add fs error monitoring example Gabriel Krisman Bertazi
2021-10-19 15:49   ` Jan Kara
2021-10-28 15:18   ` Guenter Roeck
2021-10-28 18:56     ` Gabriel Krisman Bertazi
2021-10-28 19:56       ` Guenter Roeck
2021-11-01 11:42       ` Jan Kara
2021-10-19  0:00 ` [PATCH v8 32/32] docs: Document the FAN_FS_ERROR event Gabriel Krisman Bertazi
2021-10-19 16:47   ` Jan Kara

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