Merge patch series "fs: generic file IO error reporting"

Darrick J. Wong <djwong@kernel.org> says:

This patchset adds some generic helpers so that filesystems can report
errors to fsnotify in a standard way.  Then it adapts iomap to use the
generic helpers so that any iomap-enabled filesystem can report I/O
errors through this mechanism as well.  Finally, it makes XFS report
metadata errors through this mechanism in much the same way that ext4
does now.

These are a prerequisite for the XFS self-healing series which will
come at a later time.

* patches from https://patch.msgid.link/176826402528.3490369.2415315475116356277.stgit@frogsfrogsfrogs:
  ext4: convert to new fserror helpers
  xfs: translate fsdax media errors into file "data lost" errors when convenient
  xfs: report fs metadata errors via fsnotify
  iomap: report file I/O errors to the VFS
  fs: report filesystem and file I/O errors to fsnotify
  uapi: promote EFSCORRUPTED and EUCLEAN to errno.h

Link: https://patch.msgid.link/176826402528.3490369.2415315475116356277.stgit@frogsfrogsfrogs
Signed-off-by: Christian Brauner <brauner@kernel.org>

4 files changed, 84 insertions, 3 deletions

diff --git a/include/linux/fs/super_types.h b/include/linux/fs/super_types.h
index 6bd3009e09b3..97a8552d8f2b 100644
--- a/include/linux/fs/super_types.h
+++ b/include/linux/fs/super_types.h
@@ -35,6 +35,7 @@ struct user_namespace;
 struct workqueue_struct;
 struct writeback_control;
 struct xattr_handler;
+struct fserror_event;
 
 extern struct super_block *blockdev_superblock;
 
@@ -124,6 +125,9 @@ struct super_operations {
 	 */
 	int (*remove_bdev)(struct super_block *sb, struct block_device *bdev);
 	void (*shutdown)(struct super_block *sb);
+
+	/* Report a filesystem error */
+	void (*report_error)(const struct fserror_event *event);
 };
 
 struct super_block {
@@ -268,6 +272,9 @@ struct super_block {
 	spinlock_t				s_inode_wblist_lock;
 	struct list_head			s_inodes_wb;	/* writeback inodes */
 	long					s_min_writeback_pages;
+
+	/* number of fserrors that are being sent to fsnotify/filesystems */
+	refcount_t				s_pending_errors;
 } __randomize_layout;
 
 /*
diff --git a/include/linux/fserror.h b/include/linux/fserror.h
new file mode 100644
index 000000000000..5e1ad78c346e
--- /dev/null
+++ b/include/linux/fserror.h
@@ -0,0 +1,75 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (c) 2025 Oracle.  All Rights Reserved.
+ * Author: Darrick J. Wong <djwong@kernel.org>
+ */
+#ifndef _LINUX_FSERROR_H__
+#define _LINUX_FSERROR_H__
+
+void fserror_mount(struct super_block *sb);
+void fserror_unmount(struct super_block *sb);
+
+enum fserror_type {
+	/* pagecache I/O failed */
+	FSERR_BUFFERED_READ,
+	FSERR_BUFFERED_WRITE,
+
+	/* direct I/O failed */
+	FSERR_DIRECTIO_READ,
+	FSERR_DIRECTIO_WRITE,
+
+	/* out of band media error reported */
+	FSERR_DATA_LOST,
+
+	/* filesystem metadata */
+	FSERR_METADATA,
+};
+
+struct fserror_event {
+	struct work_struct work;
+	struct super_block *sb;
+	struct inode *inode;
+	loff_t pos;
+	u64 len;
+	enum fserror_type type;
+
+	/* negative error number */
+	int error;
+};
+
+void fserror_report(struct super_block *sb, struct inode *inode,
+		    enum fserror_type type, loff_t pos, u64 len, int error,
+		    gfp_t gfp);
+
+static inline void fserror_report_io(struct inode *inode,
+				     enum fserror_type type, loff_t pos,
+				     u64 len, int error, gfp_t gfp)
+{
+	fserror_report(inode->i_sb, inode, type, pos, len, error, gfp);
+}
+
+static inline void fserror_report_data_lost(struct inode *inode, loff_t pos,
+					    u64 len, gfp_t gfp)
+{
+	fserror_report(inode->i_sb, inode, FSERR_DATA_LOST, pos, len, -EIO,
+		       gfp);
+}
+
+static inline void fserror_report_file_metadata(struct inode *inode, int error,
+						gfp_t gfp)
+{
+	fserror_report(inode->i_sb, inode, FSERR_METADATA, 0, 0, error, gfp);
+}
+
+static inline void fserror_report_metadata(struct super_block *sb, int error,
+					   gfp_t gfp)
+{
+	fserror_report(sb, NULL, FSERR_METADATA, 0, 0, error, gfp);
+}
+
+static inline void fserror_report_shutdown(struct super_block *sb, gfp_t gfp)
+{
+	fserror_report(sb, NULL, FSERR_METADATA, 0, 0, -ESHUTDOWN, gfp);
+}
+
+#endif /* _LINUX_FSERROR_H__ */
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index f5eaf76198f3..a53a00d36228 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -1815,7 +1815,4 @@ static inline int jbd2_handle_buffer_credits(handle_t *handle)
 
 #endif	/* __KERNEL__ */
 
-#define EFSBADCRC	EBADMSG		/* Bad CRC detected */
-#define EFSCORRUPTED	EUCLEAN		/* Filesystem is corrupted */
-
 #endif	/* _LINUX_JBD2_H */
diff --git a/include/uapi/asm-generic/errno.h b/include/uapi/asm-generic/errno.h
index cf9c51ac49f9..92e7ae493ee3 100644
--- a/include/uapi/asm-generic/errno.h
+++ b/include/uapi/asm-generic/errno.h
@@ -55,6 +55,7 @@
 #define	EMULTIHOP	72	/* Multihop attempted */
 #define	EDOTDOT		73	/* RFS specific error */
 #define	EBADMSG		74	/* Not a data message */
+#define	EFSBADCRC	EBADMSG	/* Bad CRC detected */
 #define	EOVERFLOW	75	/* Value too large for defined data type */
 #define	ENOTUNIQ	76	/* Name not unique on network */
 #define	EBADFD		77	/* File descriptor in bad state */
@@ -98,6 +99,7 @@
 #define	EINPROGRESS	115	/* Operation now in progress */
 #define	ESTALE		116	/* Stale file handle */
 #define	EUCLEAN		117	/* Structure needs cleaning */
+#define	EFSCORRUPTED	EUCLEAN	/* Filesystem is corrupted */
 #define	ENOTNAM		118	/* Not a XENIX named type file */
 #define	ENAVAIL		119	/* No XENIX semaphores available */
 #define	EISNAM		120	/* Is a named type file */