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Message-Id: <20210812214010.3197279-19-krisman@collabora.com>
Date: Thu, 12 Aug 2021 17:40:07 -0400
From: Gabriel Krisman Bertazi <krisman@...labora.com>
To: amir73il@...il.com, jack@...e.com
Cc: linux-api@...r.kernel.org, linux-ext4@...r.kernel.org,
linux-fsdevel@...r.kernel.org, khazhy@...gle.com,
dhowells@...hat.com, david@...morbit.com, tytso@....edu,
djwong@...nel.org, repnop@...gle.com,
Gabriel Krisman Bertazi <krisman@...labora.com>,
kernel@...labora.com
Subject: [PATCH v6 18/21] fanotify: Emit generic error info type for error event
The Error info type 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.
Signed-off-by: Gabriel Krisman Bertazi <krisman@...labora.com>
---
Changes since v5:
- Move error code here
---
fs/notify/fanotify/fanotify.c | 1 +
fs/notify/fanotify/fanotify.h | 1 +
fs/notify/fanotify/fanotify_user.c | 36 ++++++++++++++++++++++++++++++
include/uapi/linux/fanotify.h | 7 ++++++
4 files changed, 45 insertions(+)
diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index f5c16ac37835..b49a474c1d7f 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -745,6 +745,7 @@ static int fanotify_handle_error_event(struct fsnotify_iter_info *iter_info,
spin_unlock(&group->notification_lock);
fee->fae.type = FANOTIFY_EVENT_TYPE_FS_ERROR;
+ fee->error = report->error;
fee->fsid = fee->sb_mark->fsn_mark.connector->fsid;
fh_len = fanotify_encode_fh_len(inode);
diff --git a/fs/notify/fanotify/fanotify.h b/fs/notify/fanotify/fanotify.h
index 158cf0c4b0bd..0cfe376c6fd9 100644
--- a/fs/notify/fanotify/fanotify.h
+++ b/fs/notify/fanotify/fanotify.h
@@ -220,6 +220,7 @@ 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 */
struct fanotify_sb_mark *sb_mark; /* Back reference to the mark. */
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 1ab8f9d8b3ac..ca53159ce673 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -107,6 +107,8 @@ struct kmem_cache *fanotify_perm_event_cachep __read_mostly;
#define FANOTIFY_EVENT_ALIGN 4
#define FANOTIFY_INFO_HDR_LEN \
(sizeof(struct fanotify_event_info_fid) + sizeof(struct file_handle))
+#define FANOTIFY_INFO_ERROR_LEN \
+ (sizeof(struct fanotify_event_info_error))
static int fanotify_fid_info_len(int fh_len, int name_len)
{
@@ -130,6 +132,9 @@ static size_t fanotify_event_len(struct fanotify_event *event,
if (!fid_mode)
return event_len;
+ if (fanotify_is_error_event(event->mask))
+ event_len += FANOTIFY_INFO_ERROR_LEN;
+
info = fanotify_event_info(event);
dir_fh_len = fanotify_event_dir_fh_len(event);
fh_len = fanotify_event_object_fh_len(event);
@@ -176,6 +181,7 @@ static struct fanotify_event *fanotify_dup_error_to_stack(
error_on_stack->fae.type = FANOTIFY_EVENT_TYPE_FS_ERROR;
error_on_stack->err_count = fee->err_count;
error_on_stack->sb_mark = fee->sb_mark;
+ error_on_stack->error = fee->error;
error_on_stack->fsid = fee->fsid;
@@ -342,6 +348,28 @@ 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_INFO_ERROR_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_info_to_user(__kernel_fsid_t *fsid, struct fanotify_fh *fh,
int info_type, const char *name, size_t name_len,
char __user *buf, size_t count)
@@ -505,6 +533,14 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group,
if (f)
fd_install(fd, f);
+ if (fanotify_is_error_event(event->mask)) {
+ ret = copy_error_info_to_user(event, buf, count);
+ if (ret < 0)
+ goto out_close_fd;
+ buf += ret;
+ count -= ret;
+ }
+
/* Event info records order is: dir fid + name, child fid */
if (fanotify_event_dir_fh_len(event)) {
info_type = info->name_len ? FAN_EVENT_INFO_TYPE_DFID_NAME :
diff --git a/include/uapi/linux/fanotify.h b/include/uapi/linux/fanotify.h
index 16402037fc7a..80040a92e9d9 100644
--- a/include/uapi/linux/fanotify.h
+++ b/include/uapi/linux/fanotify.h
@@ -124,6 +124,7 @@ struct fanotify_event_metadata {
#define FAN_EVENT_INFO_TYPE_FID 1
#define FAN_EVENT_INFO_TYPE_DFID_NAME 2
#define FAN_EVENT_INFO_TYPE_DFID 3
+#define FAN_EVENT_INFO_TYPE_ERROR 4
/* Variable length info record following event metadata */
struct fanotify_event_info_header {
@@ -149,6 +150,12 @@ struct fanotify_event_info_fid {
unsigned char handle[0];
};
+struct fanotify_event_info_error {
+ struct fanotify_event_info_header hdr;
+ __s32 error;
+ __u32 error_count;
+};
+
struct fanotify_response {
__s32 fd;
__u32 response;
--
2.32.0
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