The FAN_FS_ERROR event is used by filesystem wide monitoring tools to
receive notifications of type FS_ERROR_EVENT, emited by filesystems when
a problem is detected. The error notification includes a generic error
descriptor.
Signed-off-by: Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxx>
---
Changes since v1:
- Pass dentry to fanotify_check_fsid (Amir)
- FANOTIFY_EVENT_TYPE_ERROR -> FANOTIFY_EVENT_TYPE_FS_ERROR
- Merge previous patch into it
- Use a single slot
- Move fanotify_mark.error_event definition to this commit
- Rename FAN_ERROR -> FAN_FS_ERROR
- Restrict FAN_FS_ERROR to FAN_MARK_FILESYSTEM
---
fs/notify/fanotify/fanotify.c | 115 ++++++++++++++++++++++--
fs/notify/fanotify/fanotify.h | 30 +++++++
fs/notify/fanotify/fanotify_user.c | 137 ++++++++++++++++++++++++++---
include/linux/fanotify.h | 6 +-
include/uapi/linux/fanotify.h | 11 +++
5 files changed, 281 insertions(+), 18 deletions(-)
diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index f64234489811..58b2dd01f1ae 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -247,6 +247,14 @@ static int fanotify_get_response(struct fsnotify_group *group,
return ret;
}
+static bool fanotify_event_reports_path(const struct fsnotify_group *group,
+ u32 mask)
+{
+ unsigned int fid_mode = FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS);
+
+ return !fid_mode && !fanotify_is_error_event(mask);
+}
+
/*
* This function returns a mask for an event that only contains the flags
* that have been specifically requested by the user. Flags that may have
@@ -261,7 +269,6 @@ static u32 fanotify_group_event_mask(
__u32 marks_mask = 0, marks_ignored_mask = 0;
__u32 test_mask, user_mask = FANOTIFY_OUTGOING_EVENTS |
FANOTIFY_EVENT_FLAGS;
- const struct path *path = fsnotify_event_info_path(event_info);
unsigned int fid_mode = FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS);
struct fsnotify_mark *mark;
int type;
@@ -270,14 +277,17 @@ static u32 fanotify_group_event_mask(
__func__, iter_info->report_mask, event_mask,
event_info->data, event_info->data_type);
- if (!fid_mode) {
+ if (fanotify_event_reports_path(group, event_mask)) {
+ const struct path *path;
+
/* Do we have path to open a file descriptor? */
+ path = fsnotify_event_info_path(event_info);
if (!path)
return 0;
/* Path type events are only relevant for files and dirs */
if (!d_is_reg(path->dentry) && !d_can_lookup(path->dentry))
return 0;
- } else if (!(fid_mode & FAN_REPORT_FID)) {
+ } else if (fid_mode && !(fid_mode & FAN_REPORT_FID)) {
/* Do we have a directory inode to report? */
if (!event_info->dir && !(event_mask & FS_ISDIR))
return 0;
@@ -658,6 +668,78 @@ static struct fanotify_event *fanotify_alloc_event(
return event;
}
+static void fanotify_init_error_event(struct fanotify_error_event *event,
+ __kernel_fsid_t fsid,
+ const struct fs_error_report *report)
+{
+ event->fae.type = FANOTIFY_EVENT_TYPE_FS_ERROR;
+ event->err_count = 1;
+ event->fsid = fsid;
+ event->error = report->error;
+ event->ino = (report->inode) ? report->inode->i_ino : 0;
+ event->ino_generation =
+ (report->inode) ? report->inode->i_generation : 0;
+}
+
+struct fanotify_insert_error_data {
+ const struct fs_error_report *report;
+ __kernel_fsid_t fsid;
+};
+
+static void fanotify_insert_error_event(struct fsnotify_group *group,
+ struct fsnotify_event *event,
+ const void *data)
+{
+ struct fanotify_event *fae = FANOTIFY_E(event);
+ struct fanotify_error_event *error_event = FANOTIFY_EE(fae);
+ const struct fanotify_insert_error_data *idata =
+ ((struct fanotify_insert_error_data *) data);
+
+ fsnotify_get_mark(error_event->mark);
+ fanotify_init_error_event(error_event, idata->fsid, idata->report);
+}
+
+static int fanotify_merge_error_event(struct fsnotify_group *group,
+ struct fsnotify_event *event)
+{
+ struct fanotify_event *fae = FANOTIFY_E(event);
+
+ if (!list_empty(&event->list)) {
+ FANOTIFY_EE(fae)->err_count++;
+ return 1;
+ }
+
+ return 0;
+}
+
+static int fanotify_queue_error_event(struct fsnotify_iter_info *iter_info,
+ struct fsnotify_group *group,
+ __kernel_fsid_t fsid,
+ const struct fs_error_report *report)
+{
+ struct fanotify_error_event *error_event;
+ struct fsnotify_mark *mark = fsnotify_iter_sb_mark(iter_info);
+ int ret = -ENOMEM;
+
+ if (!mark || !FANOTIFY_SB_MARK(mark)->error_event)
+ return ret;
+
+ spin_lock(&mark->lock);
+ error_event = FANOTIFY_SB_MARK(mark)->error_event;
+ if (error_event) {
+ ret = fsnotify_add_event(group, &error_event->fae.fse,
+ fanotify_merge_error_event,
+ fanotify_insert_error_event,
+ &(struct fanotify_insert_error_data) {
+ .fsid = fsid,
+ .report = report
+ });
+ }
+ spin_unlock(&mark->lock);
+
+ return ret;
+}
+
/*
* Get cached fsid of the filesystem containing the object from any connector.
* All connectors are supposed to have the same fsid, but we do not verify that
@@ -738,8 +820,9 @@ static int fanotify_handle_event(struct fsnotify_group *group, u32 mask,
BUILD_BUG_ON(FAN_ONDIR != FS_ISDIR);
BUILD_BUG_ON(FAN_OPEN_EXEC != FS_OPEN_EXEC);
BUILD_BUG_ON(FAN_OPEN_EXEC_PERM != FS_OPEN_EXEC_PERM);
+ BUILD_BUG_ON(FAN_FS_ERROR != FS_ERROR);
- BUILD_BUG_ON(HWEIGHT32(ALL_FANOTIFY_EVENT_BITS) != 19);
+ BUILD_BUG_ON(HWEIGHT32(ALL_FANOTIFY_EVENT_BITS) != 20);
mask = fanotify_group_event_mask(group, mask, event_info, iter_info);
if (!mask)
@@ -756,13 +839,20 @@ static int fanotify_handle_event(struct fsnotify_group *group, u32 mask,
return 0;
}
- if (FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS)) {
+ if (FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS) ||
+ fanotify_is_error_event(mask)) {
fsid = fanotify_get_fsid(iter_info);
/* Racing with mark destruction or creation? */
if (!fsid.val[0] && !fsid.val[1])
return 0;
}
+ if (fanotify_is_error_event(mask)) {
+ ret = fanotify_queue_error_event(iter_info, group, fsid,
+ event_info->data);
+ goto finish;
+ }
+
event = fanotify_alloc_event(group, mask, event_info, &fsid);
ret = -ENOMEM;
if (unlikely(!event)) {
@@ -831,6 +921,17 @@ static void fanotify_free_name_event(struct fanotify_event *event)
kfree(FANOTIFY_NE(event));
}
+static void fanotify_free_error_event(struct fanotify_event *event)
+{
+ /*
+ * Just drop the reference acquired by
+ * fanotify_queue_error_event.
+ *
+ * The actual memory is freed with the mark.
+ */
+ fsnotify_put_mark(FANOTIFY_EE(event)->mark);
+}
+
static void fanotify_free_event(struct fsnotify_event *fsn_event)
{
struct fanotify_event *event;
@@ -853,6 +954,9 @@ static void fanotify_free_event(struct fsnotify_event *fsn_event)
case FANOTIFY_EVENT_TYPE_OVERFLOW:
kfree(event);
break;
+ case FANOTIFY_EVENT_TYPE_FS_ERROR:
+ fanotify_free_error_event(event);
+ break;
default:
WARN_ON_ONCE(1);
}
@@ -870,6 +974,7 @@ static void fanotify_free_mark(struct fsnotify_mark *mark)
if (mark->flags & FSNOTIFY_MARK_FLAG_SB) {
struct fanotify_sb_mark *fa_mark = FANOTIFY_SB_MARK(mark);
+ kfree(fa_mark->error_event);
kmem_cache_free(fanotify_sb_mark_cache, fa_mark);
} else {
kmem_cache_free(fanotify_mark_cache, mark);
diff --git a/fs/notify/fanotify/fanotify.h b/fs/notify/fanotify/fanotify.h
index 7e00c05a979a..882d056b3a7a 100644
--- a/fs/notify/fanotify/fanotify.h
+++ b/fs/notify/fanotify/fanotify.h
@@ -132,11 +132,14 @@ static inline void fanotify_info_copy_name(struct fanotify_info *info,
struct fanotify_sb_mark {
struct fsnotify_mark fsn_mark;
+ struct fanotify_error_event *error_event;
};
static inline
struct fanotify_sb_mark *FANOTIFY_SB_MARK(struct fsnotify_mark *mark)
{
+ WARN_ON(!(mark->flags & FSNOTIFY_MARK_FLAG_SB));
+
return container_of(mark, struct fanotify_sb_mark, fsn_mark);
}
@@ -152,6 +155,7 @@ enum fanotify_event_type {
FANOTIFY_EVENT_TYPE_PATH,
FANOTIFY_EVENT_TYPE_PATH_PERM,
FANOTIFY_EVENT_TYPE_OVERFLOW, /* struct fanotify_event */
+ FANOTIFY_EVENT_TYPE_FS_ERROR, /* struct fanotify_error_event */
__FANOTIFY_EVENT_TYPE_NUM
};
@@ -207,12 +211,32 @@ FANOTIFY_NE(struct fanotify_event *event)
return container_of(event, struct fanotify_name_event, fae);
}
+struct fanotify_error_event {
+ struct fanotify_event fae;
+ s32 error;
+ u32 err_count;
+ __kernel_fsid_t fsid;
+ u64 ino;
+ u32 ino_generation;
+
+ /* Back reference to the mark this error refers to. */
+ struct fsnotify_mark *mark;
+};
+
+static inline struct fanotify_error_event *
+FANOTIFY_EE(struct fanotify_event *event)
+{
+ return container_of(event, struct fanotify_error_event, fae);
+}
+
static inline __kernel_fsid_t *fanotify_event_fsid(struct fanotify_event *event)
{
if (event->type == FANOTIFY_EVENT_TYPE_FID)
return &FANOTIFY_FE(event)->fsid;
else if (event->type == FANOTIFY_EVENT_TYPE_FID_NAME)
return &FANOTIFY_NE(event)->fsid;
+ else if (event->type == FANOTIFY_EVENT_TYPE_FS_ERROR)
+ return &FANOTIFY_EE(event)->fsid;
else
return NULL;
}
@@ -298,6 +322,11 @@ static inline struct fanotify_event *FANOTIFY_E(struct fsnotify_event *fse)
return container_of(fse, struct fanotify_event, fse);
}
+static inline bool fanotify_is_error_event(u32 mask)
+{
+ return mask & FANOTIFY_ERROR_EVENTS;
+}
+
static inline bool fanotify_event_has_path(struct fanotify_event *event)
{
return event->type == FANOTIFY_EVENT_TYPE_PATH ||
@@ -327,6 +356,7 @@ static inline struct path *fanotify_event_path(struct fanotify_event *event)
static inline bool fanotify_is_hashed_event(u32 mask)
{
return !(fanotify_is_perm_event(mask) ||
+ fanotify_is_error_event(mask) ||
fsnotify_is_overflow_event(mask));
}
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index db378480f1b1..7ec99bec2746 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)
{
@@ -127,6 +129,9 @@ static size_t fanotify_event_len(struct fanotify_event *event,
int fh_len;
int dot_len = 0;
+ if (fanotify_is_error_event(event->mask))
+ return event_len + FANOTIFY_INFO_ERROR_LEN;
+
if (!fid_mode)
return event_len;
@@ -150,6 +155,35 @@ static size_t fanotify_event_len(struct fanotify_event *event,
return event_len;
}
+static struct fanotify_event *fanotify_dequeue_error_event(
+ struct fsnotify_group *group,
+ struct fanotify_event *event,
+ struct fanotify_error_event *dest)
+{
+ struct fanotify_error_event *error_event = FANOTIFY_EE(event);
+
+ /*
+ * In order to avoid missing an error count update, the
+ * queued event is de-queued and duplicated to an
+ * in-stack fanotify_error_event while still inside
+ * mark->lock. Once the event is dequeued, it can be
+ * immediately re-used for a new event.
+ *
+ * The ownership of the mark reference is dropped later
+ * by destroy_event.
+ */
+ spin_lock(&error_event->mark->lock);
+
+ memcpy(dest, error_event, sizeof(*error_event));
+ fsnotify_init_event(&dest->fae.fse);
+
+ fsnotify_remove_queued_event(group, &event->fse);
+
+ spin_unlock(&error_event->mark->lock);
+
+ return &dest->fae;
+}
+
/*
* Remove an hashed event from merge hash table.
*/
@@ -173,8 +207,10 @@ static void fanotify_unhash_event(struct fsnotify_group *group,
* is not large enough. When permission event is dequeued, its state is
* updated accordingly.
*/
-static struct fanotify_event *get_one_event(struct fsnotify_group *group,
- size_t count)
+static struct fanotify_event *get_one_event(
+ struct fsnotify_group *group,
+ size_t count,
+ struct fanotify_error_event *error_event)
{
size_t event_size;
struct fanotify_event *event = NULL;
@@ -198,9 +234,14 @@ static struct fanotify_event *get_one_event(struct fsnotify_group *group,
/*
* Held the notification_lock the whole time, so this is the
- * same event we peeked above.
+ * same event we peeked above, unless it is copied to
+ * error_event.
*/
- fsnotify_remove_first_event(group);
+ if (fanotify_is_error_event(event->mask))
+ event = fanotify_dequeue_error_event(group, event, error_event);
+ else
+ fsnotify_remove_first_event(group);
+
if (fanotify_is_perm_event(event->mask))
FANOTIFY_PERM(event)->state = FAN_EVENT_REPORTED;
if (fanotify_is_hashed_event(event->mask))
@@ -310,6 +351,31 @@ 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 = sizeof(struct fanotify_event_info_error);
+
+ if (WARN_ON(count < info.hdr.len))
+ return -EFAULT;
+
+ info.fsid = fee->fsid;
+ info.error = fee->error;
+ info.ino = fee->ino;
+ info.ino_generation = fee->ino_generation;
+ 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)
@@ -531,6 +597,14 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group,
count -= 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;
+ }
+
return metadata.event_len;
out_close_fd:
@@ -559,6 +633,7 @@ static __poll_t fanotify_poll(struct file *file, poll_table *wait)
static ssize_t fanotify_read(struct file *file, char __user *buf,
size_t count, loff_t *pos)
{
+ struct fanotify_error_event error_event;
struct fsnotify_group *group;
struct fanotify_event *event;
char __user *start;
@@ -577,7 +652,7 @@ static ssize_t fanotify_read(struct file *file, char __user *buf,
* in case there are lots of available events.
*/
cond_resched();
- event = get_one_event(group, count);
+ event = get_one_event(group, count, &error_event);
if (IS_ERR(event)) {
ret = PTR_ERR(event);
break;
@@ -896,16 +971,34 @@ static int fanotify_remove_inode_mark(struct fsnotify_group *group,
flags, umask);
}
-static __u32 fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark,
- __u32 mask,
- unsigned int flags)
+static int fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark,
+ __u32 mask, unsigned int flags,
+ __u32 *added_mask)
{
+ struct fanotify_error_event *error_event = NULL;
+ bool ignored = flags & FAN_MARK_IGNORED_MASK;
__u32 oldmask = -1;
+ /* Only pre-alloc error_event if needed. */
+ if (!ignored && (mask & FAN_FS_ERROR) &&
+ (fsn_mark->flags & FSNOTIFY_MARK_FLAG_SB) &&
+ !FANOTIFY_SB_MARK(fsn_mark)->error_event) {
+ error_event = kzalloc(sizeof(*error_event), GFP_KERNEL);
+ if (!error_event)
+ return -ENOMEM;
+ fanotify_init_event(&error_event->fae, 0, FS_ERROR);
+ error_event->mark = fsn_mark;
+ }
+
spin_lock(&fsn_mark->lock);
- if (!(flags & FAN_MARK_IGNORED_MASK)) {
+ if (!ignored) {
oldmask = fsn_mark->mask;
fsn_mark->mask |= mask;
+
+ if (error_event && !FANOTIFY_SB_MARK(fsn_mark)->error_event) {
+ FANOTIFY_SB_MARK(fsn_mark)->error_event = error_event;
+ error_event = NULL;
+ }
} else {
fsn_mark->ignored_mask |= mask;
if (flags & FAN_MARK_IGNORED_SURV_MODIFY)
@@ -913,7 +1006,10 @@ static __u32 fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark,
}
spin_unlock(&fsn_mark->lock);
- return mask & ~oldmask;
+ kfree(error_event);
+
+ *added_mask = mask & ~oldmask;
+ return 0;
}
static struct fsnotify_mark *fanotify_alloc_mark(unsigned int type)
@@ -987,6 +1083,7 @@ static int fanotify_add_mark(struct fsnotify_group *group,
{
struct fsnotify_mark *fsn_mark;
__u32 added;
+ int ret = 0;
mutex_lock(&group->mark_mutex);
fsn_mark = fsnotify_find_mark(connp, group);
@@ -997,13 +1094,18 @@ static int fanotify_add_mark(struct fsnotify_group *group,
return PTR_ERR(fsn_mark);
}
}
- added = fanotify_mark_add_to_mask(fsn_mark, mask, flags);
+ ret = fanotify_mark_add_to_mask(fsn_mark, mask, flags, &added);
+ if (ret)
+ goto out;
+
if (added & ~fsnotify_conn_mask(fsn_mark->connector))
fsnotify_recalc_mask(fsn_mark->connector);
+
+out:
mutex_unlock(&group->mark_mutex);
fsnotify_put_mark(fsn_mark);
- return 0;
+ return ret;
}
static int fanotify_add_vfsmount_mark(struct fsnotify_group *group,
@@ -1419,6 +1521,17 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
fsid = &__fsid;
}
+ if (mask & FAN_FS_ERROR) {
+ if (mark_type != FAN_MARK_FILESYSTEM) {
+ ret = -EINVAL;
+ goto path_put_and_out;
+ }
+
+ ret = fanotify_test_fsid(path.dentry, &__fsid);
+ if (ret)
+ goto path_put_and_out;
+ fsid = &__fsid;
+ }
/* inode held in place by reference to path; group by fget on fd */
if (mark_type == FAN_MARK_INODE)
diff --git a/include/linux/fanotify.h b/include/linux/fanotify.h
index a16dbeced152..3bdfe227e2c2 100644
--- a/include/linux/fanotify.h
+++ b/include/linux/fanotify.h
@@ -85,9 +85,12 @@ extern struct ctl_table fanotify_table[]; /* for sysctl */
#define FANOTIFY_INODE_EVENTS (FANOTIFY_DIRENT_EVENTS | \
FAN_ATTRIB | FAN_MOVE_SELF | FAN_DELETE_SELF)
+#define FANOTIFY_ERROR_EVENTS (FAN_FS_ERROR)
+
/* Events that user can request to be notified on */
#define FANOTIFY_EVENTS (FANOTIFY_PATH_EVENTS | \
- FANOTIFY_INODE_EVENTS)
+ FANOTIFY_INODE_EVENTS | \
+ FANOTIFY_ERROR_EVENTS)
/* Events that require a permission response from user */
#define FANOTIFY_PERM_EVENTS (FAN_OPEN_PERM | FAN_ACCESS_PERM | \
@@ -99,6 +102,7 @@ extern struct ctl_table fanotify_table[]; /* for sysctl */
/* Events that may be reported to user */
#define FANOTIFY_OUTGOING_EVENTS (FANOTIFY_EVENTS | \
FANOTIFY_PERM_EVENTS | \
+ FANOTIFY_ERROR_EVENTS | \
FAN_Q_OVERFLOW | FAN_ONDIR)
#define ALL_FANOTIFY_EVENT_BITS (FANOTIFY_OUTGOING_EVENTS | \
diff --git a/include/uapi/linux/fanotify.h b/include/uapi/linux/fanotify.h
index fbf9c5c7dd59..a987150a446c 100644
--- a/include/uapi/linux/fanotify.h
+++ b/include/uapi/linux/fanotify.h
@@ -20,6 +20,7 @@
#define FAN_OPEN_EXEC 0x00001000 /* File was opened for exec */
#define FAN_Q_OVERFLOW 0x00004000 /* Event queued overflowed */
+#define FAN_FS_ERROR 0x00008000 /* Filesystem error */
#define FAN_OPEN_PERM 0x00010000 /* File open in perm check */
#define FAN_ACCESS_PERM 0x00020000 /* File accessed in perm check */
@@ -123,6 +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 {
@@ -148,6 +150,15 @@ 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;
+ __kernel_fsid_t fsid;
+ __u64 ino;
+ __u32 ino_generation;
+};
+
struct fanotify_response {
__s32 fd;
__u32 response;
--
2.31.0
