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References: <20210615235556.970928-1-krisman@collabora.com> <20210615235556.970928-10-krisman@collabora.com>
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From:   Amir Goldstein <amir73il@gmail.com>
Date:   Wed, 16 Jun 2021 12:29:44 +0300
Message-ID: <CAOQ4uxjNLR9ohUoF+P=bO0ZxA1qSGfpLJePXVuDcowapwOLoLQ@mail.gmail.com>
Subject: Re: [PATCH v2 09/14] fsnotify: Support FS_ERROR event type
To:     Gabriel Krisman Bertazi <krisman@collabora.com>
Cc:     kernel@collabora.com, "Darrick J. Wong" <djwong@kernel.org>,
        Theodore Tso <tytso@mit.edu>,
        Dave Chinner <david@fromorbit.com>, Jan Kara <jack@suse.com>,
        David Howells <dhowells@redhat.com>,
        Khazhismel Kumykov <khazhy@google.com>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        Ext4 <linux-ext4@vger.kernel.org>
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On Wed, Jun 16, 2021 at 2:56 AM Gabriel Krisman Bertazi
<krisman@collabora.com> wrote:
>
> Expose a new type of fsnotify event for filesystems to report errors for
> userspace monitoring tools.  fanotify will send this type of
> notification for FAN_ERROR events.

FAN_FS_ERROR... it's all over the place ;-)

Otherwise
Reviewed-by: Amir Goldstein <amir73il@gmail.com>

>
> Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
>
> ---
> Changes since v1:
>   - Overload FS_ERROR with FS_IN_IGNORED
>   - IMplement support for this type on fsnotify_data_inode
> ---
>  include/linux/fsnotify_backend.h | 17 ++++++++++++++++-
>  1 file changed, 16 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
> index 8222fe12a6c9..ea5f5c7cc381 100644
> --- a/include/linux/fsnotify_backend.h
> +++ b/include/linux/fsnotify_backend.h
> @@ -42,6 +42,12 @@
>
>  #define FS_UNMOUNT             0x00002000      /* inode on umount fs */
>  #define FS_Q_OVERFLOW          0x00004000      /* Event queued overflowed */
> +#define FS_ERROR               0x00008000      /* Filesystem Error (fanotify) */
> +
> +/*
> + * FS_IN_IGNORED overloads FS_ERROR.  It is only used internally by inotify
> + * which does not support FS_ERROR.
> + */
>  #define FS_IN_IGNORED          0x00008000      /* last inotify event here */
>
>  #define FS_OPEN_PERM           0x00010000      /* open event in an permission hook */
> @@ -95,7 +101,8 @@
>  #define ALL_FSNOTIFY_EVENTS (ALL_FSNOTIFY_DIRENT_EVENTS | \
>                              FS_EVENTS_POSS_ON_CHILD | \
>                              FS_DELETE_SELF | FS_MOVE_SELF | FS_DN_RENAME | \
> -                            FS_UNMOUNT | FS_Q_OVERFLOW | FS_IN_IGNORED)
> +                            FS_UNMOUNT | FS_Q_OVERFLOW | FS_IN_IGNORED | \
> +                            FS_ERROR)
>
>  /* Extra flags that may be reported with event or control handling of events */
>  #define ALL_FSNOTIFY_FLAGS  (FS_EXCL_UNLINK | FS_ISDIR | FS_IN_ONESHOT | \
> @@ -263,6 +270,12 @@ enum fsnotify_data_type {
>         FSNOTIFY_EVENT_NONE,
>         FSNOTIFY_EVENT_PATH,
>         FSNOTIFY_EVENT_INODE,
> +       FSNOTIFY_EVENT_ERROR,
> +};
> +
> +struct fs_error_report {
> +       int error;
> +       struct inode *inode;
>  };
>
>  static inline struct inode *fsnotify_data_inode(const void *data, int data_type)
> @@ -272,6 +285,8 @@ static inline struct inode *fsnotify_data_inode(const void *data, int data_type)
>                 return (struct inode *)data;
>         case FSNOTIFY_EVENT_PATH:
>                 return d_inode(((const struct path *)data)->dentry);
> +       case FSNOTIFY_EVENT_ERROR:
> +               return ((struct fs_error_report *)data)->inode;
>         default:
>                 return NULL;
>         }
> --
> 2.31.0
>