Commit 130a3c74 authored by Gabriel Krisman Bertazi's avatar Gabriel Krisman Bertazi Committed by Jan Kara
Browse files

fanotify: Emit generic error info for error event 

The error info is a record sent to users on FAN_FS_ERROR events
documenting the type of error.  It also carries an error count,
documenting how many errors were observed since the last reporting.

Link: https://lore.kernel.org/r/20211025192746.66445-28-krisman@collabora.com


Reviewed-by: default avatarAmir Goldstein <amir73il@gmail.com>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarGabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
parent 936d6a38

fs/notify/fanotify/fanotify.c

+1 −0
Original line number Diff line number Diff line
@@ -621,6 +621,7 @@ static struct fanotify_event *fanotify_alloc_error_event( 
		return NULL;



	fee->fae.type = FANOTIFY_EVENT_TYPE_FS_ERROR;

	fee->error = report->error;

	fee->err_count = 1;

	fee->fsid = *fsid;

fs/notify/fanotify/fanotify.h

+1 −0
Original line number Diff line number Diff line
@@ -205,6 +205,7 @@ FANOTIFY_NE(struct fanotify_event *event) 


struct fanotify_error_event {

	struct fanotify_event fae;

	s32 error; /* Error reported by the Filesystem. */

	u32 err_count; /* Suppressed errors count */



	__kernel_fsid_t fsid; /* FSID this error refers to. */

fs/notify/fanotify/fanotify_user.c

+36 −0
Original line number Diff line number Diff line
@@ -115,6 +115,8 @@ struct kmem_cache *fanotify_perm_event_cachep __read_mostly; 
	(sizeof(struct fanotify_event_info_fid) + sizeof(struct file_handle))

#define FANOTIFY_PIDFD_INFO_HDR_LEN \

	sizeof(struct fanotify_event_info_pidfd)

#define FANOTIFY_ERROR_INFO_LEN \

	(sizeof(struct fanotify_event_info_error))



static int fanotify_fid_info_len(int fh_len, int name_len)

{
@@ -139,6 +141,9 @@ static size_t fanotify_event_len(unsigned int info_mode, 
	if (!info_mode)

		return event_len;



	if (fanotify_is_error_event(event->mask))

		event_len += FANOTIFY_ERROR_INFO_LEN;



	info = fanotify_event_info(event);



	if (fanotify_event_has_dir_fh(event)) {
@@ -324,6 +329,28 @@ static int process_access_response(struct fsnotify_group *group, 
	return -ENOENT;

}



static size_t copy_error_info_to_user(struct fanotify_event *event,

				      char __user *buf, int count)

{

	struct fanotify_event_info_error info;

	struct fanotify_error_event *fee = FANOTIFY_EE(event);



	info.hdr.info_type = FAN_EVENT_INFO_TYPE_ERROR;

	info.hdr.pad = 0;

	info.hdr.len = FANOTIFY_ERROR_INFO_LEN;



	if (WARN_ON(count < info.hdr.len))

		return -EFAULT;



	info.error = fee->error;

	info.error_count = fee->err_count;



	if (copy_to_user(buf, &info, sizeof(info)))

		return -EFAULT;



	return info.hdr.len;

}



static int copy_fid_info_to_user(__kernel_fsid_t *fsid, struct fanotify_fh *fh,

				 int info_type, const char *name,

				 size_t name_len,
@@ -530,6 +557,15 @@ static int copy_info_records_to_user(struct fanotify_event *event, 
		total_bytes += ret;

	}



	if (fanotify_is_error_event(event->mask)) {

		ret = copy_error_info_to_user(event, buf, count);

		if (ret < 0)

			return ret;

		buf += ret;

		count -= ret;

		total_bytes += ret;

	}



	return total_bytes;

}

include/uapi/linux/fanotify.h

+7 −0
Original line number Diff line number Diff line
@@ -126,6 +126,7 @@ struct fanotify_event_metadata { 
#define FAN_EVENT_INFO_TYPE_DFID_NAME	2

#define FAN_EVENT_INFO_TYPE_DFID	3

#define FAN_EVENT_INFO_TYPE_PIDFD	4

#define FAN_EVENT_INFO_TYPE_ERROR	5



/* Variable length info record following event metadata */

struct fanotify_event_info_header {
@@ -160,6 +161,12 @@ struct fanotify_event_info_pidfd { 
	__s32 pidfd;

};



struct fanotify_event_info_error {

	struct fanotify_event_info_header hdr;

	__s32 error;

	__u32 error_count;

};



struct fanotify_response {

	__s32 fd;

	__u32 response;