diff options
| -rw-r--r-- | fs/notify/fsnotify.c | 21 | ||||
| -rw-r--r-- | fs/notify/inotify/inotify_user.c | 2 | ||||
| -rw-r--r-- | fs/notify/mark.c | 8 |
3 files changed, 19 insertions, 12 deletions
diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c index 272c8a1dab3c..82ae8254c068 100644 --- a/fs/notify/fsnotify.c +++ b/fs/notify/fsnotify.c @@ -183,8 +183,10 @@ static bool fsnotify_event_needs_parent(struct inode *inode, __u32 mnt_mask, BUILD_BUG_ON(FS_EVENTS_POSS_ON_CHILD & ~FS_EVENTS_POSS_TO_PARENT); /* Did either inode/sb/mount subscribe for events with parent/name? */ - marks_mask |= fsnotify_parent_needed_mask(inode->i_fsnotify_mask); - marks_mask |= fsnotify_parent_needed_mask(inode->i_sb->s_fsnotify_mask); + marks_mask |= fsnotify_parent_needed_mask( + READ_ONCE(inode->i_fsnotify_mask)); + marks_mask |= fsnotify_parent_needed_mask( + READ_ONCE(inode->i_sb->s_fsnotify_mask)); marks_mask |= fsnotify_parent_needed_mask(mnt_mask); /* Did they subscribe for this event with parent/name info? */ @@ -195,8 +197,8 @@ static bool fsnotify_event_needs_parent(struct inode *inode, __u32 mnt_mask, static inline bool fsnotify_object_watched(struct inode *inode, __u32 mnt_mask, __u32 mask) { - __u32 marks_mask = inode->i_fsnotify_mask | mnt_mask | - inode->i_sb->s_fsnotify_mask; + __u32 marks_mask = READ_ONCE(inode->i_fsnotify_mask) | mnt_mask | + READ_ONCE(inode->i_sb->s_fsnotify_mask); return mask & marks_mask & ALL_FSNOTIFY_EVENTS; } @@ -213,7 +215,8 @@ int __fsnotify_parent(struct dentry *dentry, __u32 mask, const void *data, int data_type) { const struct path *path = fsnotify_data_path(data, data_type); - __u32 mnt_mask = path ? real_mount(path->mnt)->mnt_fsnotify_mask : 0; + __u32 mnt_mask = path ? + READ_ONCE(real_mount(path->mnt)->mnt_fsnotify_mask) : 0; struct inode *inode = d_inode(dentry); struct dentry *parent; bool parent_watched = dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED; @@ -557,13 +560,13 @@ int fsnotify(__u32 mask, const void *data, int data_type, struct inode *dir, (!inode2 || !inode2->i_fsnotify_marks)) return 0; - marks_mask = sb->s_fsnotify_mask; + marks_mask = READ_ONCE(sb->s_fsnotify_mask); if (mnt) - marks_mask |= mnt->mnt_fsnotify_mask; + marks_mask |= READ_ONCE(mnt->mnt_fsnotify_mask); if (inode) - marks_mask |= inode->i_fsnotify_mask; + marks_mask |= READ_ONCE(inode->i_fsnotify_mask); if (inode2) - marks_mask |= inode2->i_fsnotify_mask; + marks_mask |= READ_ONCE(inode2->i_fsnotify_mask); /* diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c index c7e451d5bd51..0794dcaf1e47 100644 --- a/fs/notify/inotify/inotify_user.c +++ b/fs/notify/inotify/inotify_user.c @@ -569,7 +569,7 @@ static int inotify_update_existing_watch(struct fsnotify_group *group, /* more bits in old than in new? */ int dropped = (old_mask & ~new_mask); /* more bits in this fsn_mark than the inode's mask? */ - int do_inode = (new_mask & ~inode->i_fsnotify_mask); + int do_inode = (new_mask & ~READ_ONCE(inode->i_fsnotify_mask)); /* update the inode with this new fsn_mark */ if (dropped || do_inode) diff --git a/fs/notify/mark.c b/fs/notify/mark.c index 5e170e713088..c45b222cf9c1 100644 --- a/fs/notify/mark.c +++ b/fs/notify/mark.c @@ -128,7 +128,7 @@ __u32 fsnotify_conn_mask(struct fsnotify_mark_connector *conn) if (WARN_ON(!fsnotify_valid_obj_type(conn->type))) return 0; - return *fsnotify_conn_mask_p(conn); + return READ_ONCE(*fsnotify_conn_mask_p(conn)); } static void fsnotify_get_sb_watched_objects(struct super_block *sb) @@ -245,7 +245,11 @@ static void *__fsnotify_recalc_mask(struct fsnotify_mark_connector *conn) !(mark->flags & FSNOTIFY_MARK_FLAG_NO_IREF)) want_iref = true; } - *fsnotify_conn_mask_p(conn) = new_mask; + /* + * We use WRITE_ONCE() to prevent silly compiler optimizations from + * confusing readers not holding conn->lock with partial updates. + */ + WRITE_ONCE(*fsnotify_conn_mask_p(conn), new_mask); return fsnotify_update_iref(conn, want_iref); } |