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Date: Thu, 12 Aug 2021 17:40:04 -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 15/21] fanotify: Preallocate per superblock mark error event
Error reporting needs to be done in an atomic context. This patch
introduces a single error slot for superblock marks that report the
FAN_FS_ERROR event, to be used during event submission.
Signed-off-by: Gabriel Krisman Bertazi <krisman@...labora.com>
---
Changes v5:
- Restore mark references. (jan)
- Tie fee slot to the mark lifetime.(jan)
- Don't reallocate event(jan)
---
fs/notify/fanotify/fanotify.c | 12 ++++++++++++
fs/notify/fanotify/fanotify.h | 13 +++++++++++++
fs/notify/fanotify/fanotify_user.c | 31 ++++++++++++++++++++++++++++--
3 files changed, 54 insertions(+), 2 deletions(-)
diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index ebb6c557cea1..3bf6fd85c634 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -855,6 +855,14 @@ static void fanotify_free_name_event(struct fanotify_event *event)
kfree(FANOTIFY_NE(event));
}
+static void fanotify_free_error_event(struct fanotify_event *event)
+{
+ /*
+ * The actual event is tied to a mark, and is released on mark
+ * removal
+ */
+}
+
static void fanotify_free_event(struct fsnotify_event *fsn_event)
{
struct fanotify_event *event;
@@ -877,6 +885,9 @@ 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);
}
@@ -894,6 +905,7 @@ static void fanotify_free_mark(struct fsnotify_mark *mark)
if (mark->flags & FANOTIFY_MARK_FLAG_SB_MARK) {
struct fanotify_sb_mark *fa_mark = FANOTIFY_SB_MARK(mark);
+ kfree(fa_mark->fee_slot);
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 b3ab620822c2..3f03333df32f 100644
--- a/fs/notify/fanotify/fanotify.h
+++ b/fs/notify/fanotify/fanotify.h
@@ -139,6 +139,7 @@ enum fanotify_mark_bits {
struct fanotify_sb_mark {
struct fsnotify_mark fsn_mark;
+ struct fanotify_error_event *fee_slot;
};
static inline
@@ -161,6 +162,7 @@ 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
};
@@ -216,6 +218,17 @@ FANOTIFY_NE(struct fanotify_event *event)
return container_of(event, struct fanotify_name_event, fae);
}
+struct fanotify_error_event {
+ struct fanotify_event fae;
+ struct fanotify_sb_mark *sb_mark; /* Back reference to the 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)
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 54107f1533d5..b77030386d7f 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -947,8 +947,10 @@ static struct fsnotify_mark *fanotify_alloc_mark(struct fsnotify_group *group,
fsnotify_init_mark(mark, group);
- if (type == FSNOTIFY_OBJ_TYPE_SB)
+ if (type == FSNOTIFY_OBJ_TYPE_SB) {
mark->flags |= FANOTIFY_MARK_FLAG_SB_MARK;
+ sb_mark->fee_slot = NULL;
+ }
return mark;
}
@@ -999,6 +1001,7 @@ 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);
@@ -1009,13 +1012,37 @@ static int fanotify_add_mark(struct fsnotify_group *group,
return PTR_ERR(fsn_mark);
}
}
+
+ /*
+ * Error events are allocated per super-block mark only if
+ * strictly needed (i.e. FAN_FS_ERROR was requested).
+ */
+ if (type == FSNOTIFY_OBJ_TYPE_SB && !(flags & FAN_MARK_IGNORED_MASK) &&
+ (mask & FAN_FS_ERROR)) {
+ struct fanotify_sb_mark *sb_mark = FANOTIFY_SB_MARK(fsn_mark);
+
+ if (!sb_mark->fee_slot) {
+ struct fanotify_error_event *fee =
+ kzalloc(sizeof(*fee), GFP_KERNEL_ACCOUNT);
+ if (!fee) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ fanotify_init_event(&fee->fae, 0, FS_ERROR);
+ fee->sb_mark = sb_mark;
+ sb_mark->fee_slot = fee;
+ }
+ }
+
added = fanotify_mark_add_to_mask(fsn_mark, mask, flags);
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,
--
2.32.0
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