Re: [PATCH v6 10/21] fsnotify: Support FS_ERROR event type

---
Changes since v5:
  - pass sb inside data field (jan)
Changes since v3:
  - Squash patch ("fsnotify: Introduce helpers to send error_events")
  - Drop reviewed-bys!

Changes since v2:
  - FAN_ERROR->FAN_FS_ERROR (Amir)

Changes since v1:
  - Overload FS_ERROR with FS_IN_IGNORED
  - Implement support for this type on fsnotify_data_inode (Amir)
---
 fs/notify/fsnotify.c             |  3 +++
 include/linux/fsnotify.h         | 13 +++++++++++++
 include/linux/fsnotify_backend.h | 18 +++++++++++++++++-
 3 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
index 536db02cb26e..6d3b3de4f8ee 100644
--- a/fs/notify/fsnotify.c
+++ b/fs/notify/fsnotify.c

@@ -103,6 +103,9 @@ static struct super_block *fsnotify_data_sb(const void *data, int data_type)
        struct inode *inode = fsnotify_data_inode(data, data_type);
        struct super_block *sb = inode ? inode->i_sb : NULL;

+       if (!sb && data_type == FSNOTIFY_EVENT_ERROR)
+               sb = ((struct fs_error_report *) data)->sb;
+
        return sb;
 }

diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h
index f8acddcf54fb..521234af1827 100644
--- a/include/linux/fsnotify.h
+++ b/include/linux/fsnotify.h

@@ -317,4 +317,17 @@ static inline void fsnotify_change(struct dentry *dentry, unsigned int ia_valid)
                fsnotify_dentry(dentry, mask);
 }

+static inline int fsnotify_sb_error(struct super_block *sb, struct inode *inode,
+                                   int error)
+{
+       struct fs_error_report report = {
+               .error = error,
+               .inode = inode,
+               .sb = sb,
+       };
+
+       return fsnotify(FS_ERROR, &report, FSNOTIFY_EVENT_ERROR,
+                       NULL, NULL, NULL, 0);
+}
+
 #endif /* _LINUX_FS_NOTIFY_H */

diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index e027af3cd8dd..277b6f3e0998 100644
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h

@@ -42,6 +42,12 @@

 #define FS_UNMOUNT             0x00002000      /* inode on umount fs */
 #define FS_Q_OVERFLOW          0x00004000      /* Event queued overflowed */
+#define FS_ERROR               0x00008000      /* Filesystem Error (fanotify) */
+
+/*
+ * FS_IN_IGNORED overloads FS_ERROR.  It is only used internally by inotify
+ * which does not support FS_ERROR.
+ */
 #define FS_IN_IGNORED          0x00008000      /* last inotify event here */

 #define FS_OPEN_PERM           0x00010000      /* open event in an permission hook */

@@ -95,7 +101,8 @@
 #define ALL_FSNOTIFY_EVENTS (ALL_FSNOTIFY_DIRENT_EVENTS | \
                             FS_EVENTS_POSS_ON_CHILD | \
                             FS_DELETE_SELF | FS_MOVE_SELF | FS_DN_RENAME | \
-                            FS_UNMOUNT | FS_Q_OVERFLOW | FS_IN_IGNORED)
+                            FS_UNMOUNT | FS_Q_OVERFLOW | FS_IN_IGNORED | \
+                            FS_ERROR)

 /* Extra flags that may be reported with event or control handling of events */
 #define ALL_FSNOTIFY_FLAGS  (FS_EXCL_UNLINK | FS_ISDIR | FS_IN_ONESHOT | \

@@ -248,6 +255,13 @@ enum fsnotify_data_type {
        FSNOTIFY_EVENT_NONE,
        FSNOTIFY_EVENT_PATH,
        FSNOTIFY_EVENT_INODE,
+       FSNOTIFY_EVENT_ERROR,
+};
+
+struct fs_error_report {
+       int error;
+       struct inode *inode;
+       struct super_block *sb;
 };

 static inline struct inode *fsnotify_data_inode(const void *data, int data_type)

@@ -257,6 +271,8 @@ static inline struct inode *fsnotify_data_inode(const void *data, int data_type)
                return (struct inode *)data;
        case FSNOTIFY_EVENT_PATH:
                return d_inode(((const struct path *)data)->dentry);
+       case FSNOTIFY_EVENT_ERROR:
+               return ((struct fs_error_report *)data)->inode;
        default:
                return NULL;
        }
--

2.32.0