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From: Gabriel Krisman Bertazi <krisman@collabora.com>
To: Amir Goldstein <amir73il@gmail.com>
Cc: Jan Kara <jack@suse.com>, "Darrick J. Wong" <djwong@kernel.org>,
	Theodore Tso <tytso@mit.edu>, David Howells <dhowells@redhat.com>,
	Khazhismel Kumykov <khazhy@google.com>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	Ext4 <linux-ext4@vger.kernel.org>,
	Linux API <linux-api@vger.kernel.org>,
	Matthew Bobrowski <repnop@google.com>,
	kernel@collabora.com
Subject: Re: [PATCH v7 19/28] fanotify: Limit number of marks with FAN_FS_ERROR per group
Date: Fri, 15 Oct 2021 13:53:16 -0300	[thread overview]
Message-ID: <87tuhip6v7.fsf@collabora.com> (raw)
In-Reply-To: <CAOQ4uxjhTu+fPwZfjGtzcoj3-RLxBSh8ozyLjWzcTC0YJAwnwA@mail.gmail.com> (Amir Goldstein's message of "Fri, 15 Oct 2021 09:15:46 +0300")

Amir Goldstein <amir73il@gmail.com> writes:

> On Fri, Oct 15, 2021 at 12:39 AM Gabriel Krisman Bertazi
> <krisman@collabora.com> wrote:
>>
>> Since FAN_FS_ERROR memory must be pre-allocated, limit a single group
>> from watching too many file systems at once.  The current scheme
>> guarantees 1 slot per filesystem, so limit the number of marks with
>> FAN_FS_ERROR per group.
>>
>> Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
>> ---
>>  fs/notify/fanotify/fanotify_user.c | 10 ++++++++++
>>  include/linux/fsnotify_backend.h   |  1 +
>>  2 files changed, 11 insertions(+)
>>
>> diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
>> index f1cf863d6f9f..5324890500fc 100644
>> --- a/fs/notify/fanotify/fanotify_user.c
>> +++ b/fs/notify/fanotify/fanotify_user.c
>> @@ -959,6 +959,10 @@ static int fanotify_remove_mark(struct fsnotify_group *group,
>>
>>         removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags,
>>                                                  umask, &destroy_mark);
>> +
>> +       if (removed & FAN_FS_ERROR)
>> +               group->fanotify_data.error_event_marks--;
>> +
>>         if (removed & fsnotify_conn_mask(fsn_mark->connector))
>>                 fsnotify_recalc_mask(fsn_mark->connector);
>>         if (destroy_mark)
>> @@ -1057,6 +1061,9 @@ static struct fsnotify_mark *fanotify_add_new_mark(struct fsnotify_group *group,
>>
>>  static int fanotify_group_init_error_pool(struct fsnotify_group *group)
>>  {
>> +       if (group->fanotify_data.error_event_marks >= FANOTIFY_DEFAULT_FEE_POOL)
>> +               return -ENOMEM;
>
> Why not try to mempool_resize()?

Jan suggested we might not need to bother with it, but I can do that for
the next version.

> Also, I did not read the rest of the patches yet, but don't we need two
> slots per mark? one for alloc-pre-enqueue and one for free-post-dequeue?

I don't understand what you mean by two slots for alloc-pre-enqueue and
free-post-dequeue.  I suspect it is no longer necessary now that
FAN_FS_ERROR is handled like any other event on enqueue/dequeue, but can
you confirm or clarify?

Thanks,

-- 
Gabriel Krisman Bertazi

  reply	other threads:[~2021-10-15 16:53 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 ` [PATCH v7 03/28] fsnotify: clarify contract for create event hooks Gabriel Krisman Bertazi
2021-10-15  9:21   ` 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 [this message]
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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