* [PATCH 1/6] uapi: promote EFSCORRUPTED and EUCLEAN to errno.h
2026-01-13 0:31 [PATCHSET v5] fs: generic file IO error reporting Darrick J. Wong
@ 2026-01-13 0:31 ` Darrick J. Wong
2026-01-13 0:31 ` [PATCH 2/6] fs: report filesystem and file I/O errors to fsnotify Darrick J. Wong
` (5 subsequent siblings)
6 siblings, 0 replies; 21+ messages in thread
From: Darrick J. Wong @ 2026-01-13 0:31 UTC (permalink / raw)
To: djwong, brauner
Cc: hch, hsiangkao, jack, linux-api, linux-xfs, jack, linux-ext4,
linux-fsdevel, gabriel, hch, amir73il
From: Darrick J. Wong <djwong@kernel.org>
Stop definining these privately and instead move them to the uapi
errno.h so that they become canonical instead of copy pasta.
Cc: linux-api@vger.kernel.org
Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
---
arch/alpha/include/uapi/asm/errno.h | 2 ++
arch/mips/include/uapi/asm/errno.h | 2 ++
arch/parisc/include/uapi/asm/errno.h | 2 ++
arch/sparc/include/uapi/asm/errno.h | 2 ++
fs/erofs/internal.h | 2 --
fs/ext2/ext2.h | 1 -
fs/ext4/ext4.h | 3 ---
fs/f2fs/f2fs.h | 3 ---
fs/minix/minix.h | 2 --
fs/udf/udf_sb.h | 2 --
fs/xfs/xfs_linux.h | 2 --
include/linux/jbd2.h | 3 ---
include/uapi/asm-generic/errno.h | 2 ++
tools/arch/alpha/include/uapi/asm/errno.h | 2 ++
tools/arch/mips/include/uapi/asm/errno.h | 2 ++
tools/arch/parisc/include/uapi/asm/errno.h | 2 ++
tools/arch/sparc/include/uapi/asm/errno.h | 2 ++
tools/include/uapi/asm-generic/errno.h | 2 ++
18 files changed, 20 insertions(+), 18 deletions(-)
diff --git a/arch/alpha/include/uapi/asm/errno.h b/arch/alpha/include/uapi/asm/errno.h
index 3d265f6babaf0a..6791f6508632ee 100644
--- a/arch/alpha/include/uapi/asm/errno.h
+++ b/arch/alpha/include/uapi/asm/errno.h
@@ -55,6 +55,7 @@
#define ENOSR 82 /* Out of streams resources */
#define ETIME 83 /* Timer expired */
#define EBADMSG 84 /* Not a data message */
+#define EFSBADCRC EBADMSG /* Bad CRC detected */
#define EPROTO 85 /* Protocol error */
#define ENODATA 86 /* No data available */
#define ENOSTR 87 /* Device not a stream */
@@ -96,6 +97,7 @@
#define EREMCHG 115 /* Remote address changed */
#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 */
diff --git a/arch/mips/include/uapi/asm/errno.h b/arch/mips/include/uapi/asm/errno.h
index 2fb714e2d6d8fc..c01ed91b1ef44b 100644
--- a/arch/mips/include/uapi/asm/errno.h
+++ b/arch/mips/include/uapi/asm/errno.h
@@ -50,6 +50,7 @@
#define EDOTDOT 73 /* RFS specific error */
#define EMULTIHOP 74 /* Multihop attempted */
#define EBADMSG 77 /* Not a data message */
+#define EFSBADCRC EBADMSG /* Bad CRC detected */
#define ENAMETOOLONG 78 /* File name too long */
#define EOVERFLOW 79 /* Value too large for defined data type */
#define ENOTUNIQ 80 /* Name not unique on network */
@@ -88,6 +89,7 @@
#define EISCONN 133 /* Transport endpoint is already connected */
#define ENOTCONN 134 /* Transport endpoint is not connected */
#define EUCLEAN 135 /* Structure needs cleaning */
+#define EFSCORRUPTED EUCLEAN /* Filesystem is corrupted */
#define ENOTNAM 137 /* Not a XENIX named type file */
#define ENAVAIL 138 /* No XENIX semaphores available */
#define EISNAM 139 /* Is a named type file */
diff --git a/arch/parisc/include/uapi/asm/errno.h b/arch/parisc/include/uapi/asm/errno.h
index 8d94739d75c67c..8cbc07c1903e4c 100644
--- a/arch/parisc/include/uapi/asm/errno.h
+++ b/arch/parisc/include/uapi/asm/errno.h
@@ -36,6 +36,7 @@
#define EDOTDOT 66 /* RFS specific error */
#define EBADMSG 67 /* Not a data message */
+#define EFSBADCRC EBADMSG /* Bad CRC detected */
#define EUSERS 68 /* Too many users */
#define EDQUOT 69 /* Quota exceeded */
#define ESTALE 70 /* Stale file handle */
@@ -62,6 +63,7 @@
#define ERESTART 175 /* Interrupted system call should be restarted */
#define ESTRPIPE 176 /* Streams pipe error */
#define EUCLEAN 177 /* Structure needs cleaning */
+#define EFSCORRUPTED EUCLEAN /* Filesystem is corrupted */
#define ENOTNAM 178 /* Not a XENIX named type file */
#define ENAVAIL 179 /* No XENIX semaphores available */
#define EISNAM 180 /* Is a named type file */
diff --git a/arch/sparc/include/uapi/asm/errno.h b/arch/sparc/include/uapi/asm/errno.h
index 81a732b902ee38..4a41e7835fd5b8 100644
--- a/arch/sparc/include/uapi/asm/errno.h
+++ b/arch/sparc/include/uapi/asm/errno.h
@@ -48,6 +48,7 @@
#define ENOSR 74 /* Out of streams resources */
#define ENOMSG 75 /* No message of desired type */
#define EBADMSG 76 /* Not a data message */
+#define EFSBADCRC EBADMSG /* Bad CRC detected */
#define EIDRM 77 /* Identifier removed */
#define EDEADLK 78 /* Resource deadlock would occur */
#define ENOLCK 79 /* No record locks available */
@@ -91,6 +92,7 @@
#define ENOTUNIQ 115 /* Name not unique on network */
#define ERESTART 116 /* Interrupted syscall should be restarted */
#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 */
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index f7f622836198da..d06e99baf5d5ae 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -541,6 +541,4 @@ long erofs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg);
long erofs_compat_ioctl(struct file *filp, unsigned int cmd,
unsigned long arg);
-#define EFSCORRUPTED EUCLEAN /* Filesystem is corrupted */
-
#endif /* __EROFS_INTERNAL_H */
diff --git a/fs/ext2/ext2.h b/fs/ext2/ext2.h
index cf97b76e9fd3e9..5e0c6c5fcb6cd6 100644
--- a/fs/ext2/ext2.h
+++ b/fs/ext2/ext2.h
@@ -357,7 +357,6 @@ struct ext2_inode {
*/
#define EXT2_VALID_FS 0x0001 /* Unmounted cleanly */
#define EXT2_ERROR_FS 0x0002 /* Errors detected */
-#define EFSCORRUPTED EUCLEAN /* Filesystem is corrupted */
/*
* Mount flags
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 56112f201cace7..62c091b52bacdf 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -3938,7 +3938,4 @@ extern int ext4_block_write_begin(handle_t *handle, struct folio *folio,
get_block_t *get_block);
#endif /* __KERNEL__ */
-#define EFSBADCRC EBADMSG /* Bad CRC detected */
-#define EFSCORRUPTED EUCLEAN /* Filesystem is corrupted */
-
#endif /* _EXT4_H */
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 20edbb99b814a7..9f3aa3c7f12613 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -5004,7 +5004,4 @@ static inline void f2fs_invalidate_internal_cache(struct f2fs_sb_info *sbi,
f2fs_invalidate_compress_pages_range(sbi, blkaddr, len);
}
-#define EFSBADCRC EBADMSG /* Bad CRC detected */
-#define EFSCORRUPTED EUCLEAN /* Filesystem is corrupted */
-
#endif /* _LINUX_F2FS_H */
diff --git a/fs/minix/minix.h b/fs/minix/minix.h
index 2bfaf377f2086c..7e1f652f16d311 100644
--- a/fs/minix/minix.h
+++ b/fs/minix/minix.h
@@ -175,6 +175,4 @@ static inline int minix_test_bit(int nr, const void *vaddr)
__minix_error_inode((inode), __func__, __LINE__, \
(fmt), ##__VA_ARGS__)
-#define EFSCORRUPTED EUCLEAN /* Filesystem is corrupted */
-
#endif /* FS_MINIX_H */
diff --git a/fs/udf/udf_sb.h b/fs/udf/udf_sb.h
index 08ec8756b9487b..8399accc788dea 100644
--- a/fs/udf/udf_sb.h
+++ b/fs/udf/udf_sb.h
@@ -55,8 +55,6 @@
#define MF_DUPLICATE_MD 0x01
#define MF_MIRROR_FE_LOADED 0x02
-#define EFSCORRUPTED EUCLEAN
-
struct udf_meta_data {
__u32 s_meta_file_loc;
__u32 s_mirror_file_loc;
diff --git a/fs/xfs/xfs_linux.h b/fs/xfs/xfs_linux.h
index 4dd747bdbccab2..55064228c4d574 100644
--- a/fs/xfs/xfs_linux.h
+++ b/fs/xfs/xfs_linux.h
@@ -121,8 +121,6 @@ typedef __u32 xfs_nlink_t;
#define ENOATTR ENODATA /* Attribute not found */
#define EWRONGFS EINVAL /* Mount with wrong filesystem type */
-#define EFSCORRUPTED EUCLEAN /* Filesystem is corrupted */
-#define EFSBADCRC EBADMSG /* Bad CRC detected */
#define __return_address __builtin_return_address(0)
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index f5eaf76198f377..a53a00d36228ce 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 cf9c51ac49f97e..92e7ae493ee315 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 */
diff --git a/tools/arch/alpha/include/uapi/asm/errno.h b/tools/arch/alpha/include/uapi/asm/errno.h
index 3d265f6babaf0a..6791f6508632ee 100644
--- a/tools/arch/alpha/include/uapi/asm/errno.h
+++ b/tools/arch/alpha/include/uapi/asm/errno.h
@@ -55,6 +55,7 @@
#define ENOSR 82 /* Out of streams resources */
#define ETIME 83 /* Timer expired */
#define EBADMSG 84 /* Not a data message */
+#define EFSBADCRC EBADMSG /* Bad CRC detected */
#define EPROTO 85 /* Protocol error */
#define ENODATA 86 /* No data available */
#define ENOSTR 87 /* Device not a stream */
@@ -96,6 +97,7 @@
#define EREMCHG 115 /* Remote address changed */
#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 */
diff --git a/tools/arch/mips/include/uapi/asm/errno.h b/tools/arch/mips/include/uapi/asm/errno.h
index 2fb714e2d6d8fc..c01ed91b1ef44b 100644
--- a/tools/arch/mips/include/uapi/asm/errno.h
+++ b/tools/arch/mips/include/uapi/asm/errno.h
@@ -50,6 +50,7 @@
#define EDOTDOT 73 /* RFS specific error */
#define EMULTIHOP 74 /* Multihop attempted */
#define EBADMSG 77 /* Not a data message */
+#define EFSBADCRC EBADMSG /* Bad CRC detected */
#define ENAMETOOLONG 78 /* File name too long */
#define EOVERFLOW 79 /* Value too large for defined data type */
#define ENOTUNIQ 80 /* Name not unique on network */
@@ -88,6 +89,7 @@
#define EISCONN 133 /* Transport endpoint is already connected */
#define ENOTCONN 134 /* Transport endpoint is not connected */
#define EUCLEAN 135 /* Structure needs cleaning */
+#define EFSCORRUPTED EUCLEAN /* Filesystem is corrupted */
#define ENOTNAM 137 /* Not a XENIX named type file */
#define ENAVAIL 138 /* No XENIX semaphores available */
#define EISNAM 139 /* Is a named type file */
diff --git a/tools/arch/parisc/include/uapi/asm/errno.h b/tools/arch/parisc/include/uapi/asm/errno.h
index 8d94739d75c67c..8cbc07c1903e4c 100644
--- a/tools/arch/parisc/include/uapi/asm/errno.h
+++ b/tools/arch/parisc/include/uapi/asm/errno.h
@@ -36,6 +36,7 @@
#define EDOTDOT 66 /* RFS specific error */
#define EBADMSG 67 /* Not a data message */
+#define EFSBADCRC EBADMSG /* Bad CRC detected */
#define EUSERS 68 /* Too many users */
#define EDQUOT 69 /* Quota exceeded */
#define ESTALE 70 /* Stale file handle */
@@ -62,6 +63,7 @@
#define ERESTART 175 /* Interrupted system call should be restarted */
#define ESTRPIPE 176 /* Streams pipe error */
#define EUCLEAN 177 /* Structure needs cleaning */
+#define EFSCORRUPTED EUCLEAN /* Filesystem is corrupted */
#define ENOTNAM 178 /* Not a XENIX named type file */
#define ENAVAIL 179 /* No XENIX semaphores available */
#define EISNAM 180 /* Is a named type file */
diff --git a/tools/arch/sparc/include/uapi/asm/errno.h b/tools/arch/sparc/include/uapi/asm/errno.h
index 81a732b902ee38..4a41e7835fd5b8 100644
--- a/tools/arch/sparc/include/uapi/asm/errno.h
+++ b/tools/arch/sparc/include/uapi/asm/errno.h
@@ -48,6 +48,7 @@
#define ENOSR 74 /* Out of streams resources */
#define ENOMSG 75 /* No message of desired type */
#define EBADMSG 76 /* Not a data message */
+#define EFSBADCRC EBADMSG /* Bad CRC detected */
#define EIDRM 77 /* Identifier removed */
#define EDEADLK 78 /* Resource deadlock would occur */
#define ENOLCK 79 /* No record locks available */
@@ -91,6 +92,7 @@
#define ENOTUNIQ 115 /* Name not unique on network */
#define ERESTART 116 /* Interrupted syscall should be restarted */
#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 */
diff --git a/tools/include/uapi/asm-generic/errno.h b/tools/include/uapi/asm-generic/errno.h
index cf9c51ac49f97e..92e7ae493ee315 100644
--- a/tools/include/uapi/asm-generic/errno.h
+++ b/tools/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 */
^ permalink raw reply related [flat|nested] 21+ messages in thread* [PATCH 2/6] fs: report filesystem and file I/O errors to fsnotify
2026-01-13 0:31 [PATCHSET v5] fs: generic file IO error reporting Darrick J. Wong
2026-01-13 0:31 ` [PATCH 1/6] uapi: promote EFSCORRUPTED and EUCLEAN to errno.h Darrick J. Wong
@ 2026-01-13 0:31 ` Darrick J. Wong
2026-01-13 8:24 ` Christoph Hellwig
2026-01-13 0:31 ` [PATCH 3/6] iomap: report file I/O errors to the VFS Darrick J. Wong
` (4 subsequent siblings)
6 siblings, 1 reply; 21+ messages in thread
From: Darrick J. Wong @ 2026-01-13 0:31 UTC (permalink / raw)
To: djwong, brauner
Cc: hch, jack, linux-xfs, jack, linux-ext4, linux-fsdevel, gabriel,
hch, amir73il
From: Darrick J. Wong <djwong@kernel.org>
Create some wrapper code around struct super_block so that filesystems
have a standard way to queue filesystem metadata and file I/O error
reports to have them sent to fsnotify.
If a filesystem wants to provide an error number, it must supply only
negative error numbers. These are stored internally as negative
numbers, but they are converted to positive error numbers before being
passed to fanotify, per the fanotify(7) manpage. Implementations of
super_operations::report_error are passed the raw internal event data.
Note that we have to play some shenanigans with mempools and queue_work
so that the error handling doesn't happen outside of process context,
and the event handler functions (both ->report_error and fsnotify) can
handle file I/O error messages without having to worry about whatever
locks might be held. This asynchronicity requires that unmount wait for
pending events to clear.
Add a new callback to the superblock operations structure so that
filesystem drivers can themselves respond to file I/O errors if they so
desire. This will be used for an upcoming self-healing patchset for
XFS.
Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
---
include/linux/fs/super_types.h | 7 +
include/linux/fserror.h | 75 +++++++++++++++
fs/Makefile | 2
fs/fserror.c | 194 ++++++++++++++++++++++++++++++++++++++++
fs/super.c | 3 +
5 files changed, 280 insertions(+), 1 deletion(-)
create mode 100644 include/linux/fserror.h
create mode 100644 fs/fserror.c
diff --git a/include/linux/fs/super_types.h b/include/linux/fs/super_types.h
index 6bd3009e09b3b8..97a8552d8f2bc9 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 00000000000000..5e1ad78c346e27
--- /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/fs/Makefile b/fs/Makefile
index a04274a3c85420..f238cc5ea2e9d7 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -16,7 +16,7 @@ obj-y := open.o read_write.o file_table.o super.o \
stack.o fs_struct.o statfs.o fs_pin.o nsfs.o \
fs_dirent.o fs_context.o fs_parser.o fsopen.o init.o \
kernel_read_file.o mnt_idmapping.o remap_range.o pidfs.o \
- file_attr.o
+ file_attr.o fserror.o
obj-$(CONFIG_BUFFER_HEAD) += buffer.o mpage.o
obj-$(CONFIG_PROC_FS) += proc_namespace.o
diff --git a/fs/fserror.c b/fs/fserror.c
new file mode 100644
index 00000000000000..06ca86adab9b76
--- /dev/null
+++ b/fs/fserror.c
@@ -0,0 +1,194 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2025 Oracle. All Rights Reserved.
+ * Author: Darrick J. Wong <djwong@kernel.org>
+ */
+#include <linux/fs.h>
+#include <linux/fsnotify.h>
+#include <linux/mempool.h>
+#include <linux/fserror.h>
+
+#define FSERROR_DEFAULT_EVENT_POOL_SIZE (32)
+
+static struct mempool fserror_events_pool;
+
+void fserror_mount(struct super_block *sb)
+{
+ /*
+ * The pending error counter is biased by 1 so that we don't wake_var
+ * until we're actually trying to unmount.
+ */
+ refcount_set(&sb->s_pending_errors, 1);
+}
+
+void fserror_unmount(struct super_block *sb)
+{
+ /*
+ * If we don't drop the pending error count to zero, then wait for it
+ * to drop below 1, which means that the pending errors cleared and
+ * hopefully we didn't saturate with 1 billion+ concurrent events.
+ */
+ if (!refcount_dec_and_test(&sb->s_pending_errors))
+ wait_var_event(&sb->s_pending_errors,
+ refcount_read(&sb->s_pending_errors) < 1);
+}
+
+static inline void fserror_pending_dec(struct super_block *sb)
+{
+ if (refcount_dec_and_test(&sb->s_pending_errors))
+ wake_up_var(&sb->s_pending_errors);
+}
+
+static inline void fserror_free_event(struct fserror_event *event)
+{
+ fserror_pending_dec(event->sb);
+ mempool_free(event, &fserror_events_pool);
+}
+
+static void fserror_worker(struct work_struct *work)
+{
+ struct fserror_event *event =
+ container_of(work, struct fserror_event, work);
+ struct super_block *sb = event->sb;
+
+ if (sb->s_flags & SB_ACTIVE) {
+ struct fs_error_report report = {
+ /* send positive error number to userspace */
+ .error = -event->error,
+ .inode = event->inode,
+ .sb = event->sb,
+ };
+
+ if (sb->s_op->report_error)
+ sb->s_op->report_error(event);
+
+ fsnotify(FS_ERROR, &report, FSNOTIFY_EVENT_ERROR, NULL, NULL,
+ NULL, 0);
+ }
+
+ iput(event->inode);
+ fserror_free_event(event);
+}
+
+static inline struct fserror_event *fserror_alloc_event(struct super_block *sb,
+ gfp_t gfp_flags)
+{
+ struct fserror_event *event = NULL;
+
+ /*
+ * If pending_errors already reached zero or is no longer active,
+ * the superblock is being deactivated so there's no point in
+ * continuing.
+ *
+ * The order of the check of s_pending_errors and SB_ACTIVE are
+ * mandated by order of accesses in generic_shutdown_super and
+ * fserror_unmount. Barriers are implicitly provided by the refcount
+ * manipulations in this function and fserror_unmount.
+ */
+ if (!refcount_inc_not_zero(&sb->s_pending_errors))
+ return NULL;
+ if (!(sb->s_flags & SB_ACTIVE))
+ goto out_pending;
+
+ event = mempool_alloc(&fserror_events_pool, gfp_flags);
+ if (!event)
+ goto out_pending;
+
+ /* mempool_alloc doesn't support GFP_ZERO */
+ memset(event, 0, sizeof(*event));
+ event->sb = sb;
+ INIT_WORK(&event->work, fserror_worker);
+
+ return event;
+
+out_pending:
+ fserror_pending_dec(sb);
+ return NULL;
+}
+
+/**
+ * fserror_report - report a filesystem error of some kind
+ *
+ * @sb: superblock of the filesystem
+ * @inode: inode within that filesystem, if applicable
+ * @type: type of error encountered
+ * @pos: start of inode range affected, if applicable
+ * @len: length of inode range affected, if applicable
+ * @error: error number encountered, must be negative
+ * @gfp: memory allocation flags for conveying the event to a worker,
+ * since this function can be called from atomic contexts
+ *
+ * Report details of a filesystem error to the super_operations::report_error
+ * callback if present; and to fsnotify for distribution to userspace. @sb,
+ * @gfp, @type, and @error must all be specified. For file I/O errors, the
+ * @inode, @pos, and @len fields must also be specified. For file metadata
+ * errors, @inode must be specified. If @inode is not NULL, then @inode->i_sb
+ * must point to @sb.
+ *
+ * Reporting work is deferred to a workqueue to ensure that ->report_error is
+ * called from process context without any locks held. An active reference to
+ * the inode is maintained until event handling is complete, and unmount will
+ * wait for queued events to drain.
+ */
+void fserror_report(struct super_block *sb, struct inode *inode,
+ enum fserror_type type, loff_t pos, u64 len, int error,
+ gfp_t gfp)
+{
+ struct fserror_event *event;
+
+ /* sb and inode must be from the same filesystem */
+ WARN_ON_ONCE(inode && inode->i_sb != sb);
+
+ /* error number must be negative */
+ WARN_ON_ONCE(error >= 0);
+
+ event = fserror_alloc_event(sb, gfp);
+ if (!event)
+ goto lost;
+
+ event->type = type;
+ event->pos = pos;
+ event->len = len;
+ event->error = error;
+
+ /*
+ * Can't iput from non-sleeping context, so grabbing another reference
+ * to the inode must be the last thing before submitting the event.
+ */
+ if (inode) {
+ event->inode = igrab(inode);
+ if (!event->inode)
+ goto lost_event;
+ }
+
+ /*
+ * Use schedule_work here even if we're already in process context so
+ * that fsnotify and super_operations::report_error implementations are
+ * guaranteed to run in process context without any locks held. Since
+ * errors are supposed to be rare, the overhead shouldn't kill us any
+ * more than the failing device will.
+ */
+ schedule_work(&event->work);
+ return;
+
+lost_event:
+ fserror_free_event(event);
+lost:
+ if (inode)
+ pr_err_ratelimited(
+ "%s: lost file I/O error report for ino %lu type %u pos 0x%llx len 0x%llx error %d",
+ sb->s_id, inode->i_ino, type, pos, len, error);
+ else
+ pr_err_ratelimited(
+ "%s: lost filesystem error report for type %u error %d",
+ sb->s_id, type, error);
+}
+EXPORT_SYMBOL_GPL(fserror_report);
+
+static int __init fserror_init(void)
+{
+ return mempool_init_kmalloc_pool(&fserror_events_pool,
+ FSERROR_DEFAULT_EVENT_POOL_SIZE,
+ sizeof(struct fserror_event));
+}
+fs_initcall(fserror_init);
diff --git a/fs/super.c b/fs/super.c
index 3d85265d14001d..b13c1fd6a6f422 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -36,6 +36,7 @@
#include <linux/lockdep.h>
#include <linux/user_namespace.h>
#include <linux/fs_context.h>
+#include <linux/fserror.h>
#include <uapi/linux/mount.h>
#include "internal.h"
@@ -363,6 +364,7 @@ static struct super_block *alloc_super(struct file_system_type *type, int flags,
spin_lock_init(&s->s_inode_list_lock);
INIT_LIST_HEAD(&s->s_inodes_wb);
spin_lock_init(&s->s_inode_wblist_lock);
+ fserror_mount(s);
s->s_count = 1;
atomic_set(&s->s_active, 1);
@@ -622,6 +624,7 @@ void generic_shutdown_super(struct super_block *sb)
sync_filesystem(sb);
sb->s_flags &= ~SB_ACTIVE;
+ fserror_unmount(sb);
cgroup_writeback_umount(sb);
/* Evict all inodes with zero refcount. */
^ permalink raw reply related [flat|nested] 21+ messages in thread* [PATCH 3/6] iomap: report file I/O errors to the VFS
2026-01-13 0:31 [PATCHSET v5] fs: generic file IO error reporting Darrick J. Wong
2026-01-13 0:31 ` [PATCH 1/6] uapi: promote EFSCORRUPTED and EUCLEAN to errno.h Darrick J. Wong
2026-01-13 0:31 ` [PATCH 2/6] fs: report filesystem and file I/O errors to fsnotify Darrick J. Wong
@ 2026-01-13 0:31 ` Darrick J. Wong
2026-01-13 0:31 ` [PATCH 4/6] xfs: report fs metadata errors via fsnotify Darrick J. Wong
` (3 subsequent siblings)
6 siblings, 0 replies; 21+ messages in thread
From: Darrick J. Wong @ 2026-01-13 0:31 UTC (permalink / raw)
To: djwong, brauner
Cc: hch, jack, linux-xfs, jack, linux-ext4, linux-fsdevel, gabriel,
hch, amir73il
From: Darrick J. Wong <djwong@kernel.org>
Wire up iomap so that it reports all file read and write errors to the
VFS (and hence fsnotify) via the new fserror mechanism.
Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
---
fs/iomap/buffered-io.c | 23 ++++++++++++++++++++++-
fs/iomap/direct-io.c | 12 ++++++++++++
fs/iomap/ioend.c | 6 ++++++
3 files changed, 40 insertions(+), 1 deletion(-)
diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index fd9a2cf9562024..4a5f96a7c39042 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -8,6 +8,7 @@
#include <linux/writeback.h>
#include <linux/swap.h>
#include <linux/migrate.h>
+#include <linux/fserror.h>
#include "internal.h"
#include "trace.h"
@@ -371,8 +372,11 @@ static int iomap_read_inline_data(const struct iomap_iter *iter,
if (folio_test_uptodate(folio))
return 0;
- if (WARN_ON_ONCE(size > iomap->length))
+ if (WARN_ON_ONCE(size > iomap->length)) {
+ fserror_report_io(iter->inode, FSERR_BUFFERED_READ,
+ iomap->offset, size, -EIO, GFP_NOFS);
return -EIO;
+ }
if (offset > 0)
ifs_alloc(iter->inode, folio, iter->flags);
@@ -399,6 +403,11 @@ void iomap_finish_folio_read(struct folio *folio, size_t off, size_t len,
spin_unlock_irqrestore(&ifs->state_lock, flags);
}
+ if (error)
+ fserror_report_io(folio->mapping->host, FSERR_BUFFERED_READ,
+ folio_pos(folio) + off, len, error,
+ GFP_ATOMIC);
+
if (finished)
folio_end_read(folio, uptodate);
}
@@ -540,6 +549,10 @@ static int iomap_read_folio_iter(struct iomap_iter *iter,
if (!*bytes_submitted)
iomap_read_init(folio);
ret = ctx->ops->read_folio_range(iter, ctx, plen);
+ if (ret < 0)
+ fserror_report_io(iter->inode,
+ FSERR_BUFFERED_READ, pos,
+ plen, ret, GFP_NOFS);
if (ret)
return ret;
*bytes_submitted += plen;
@@ -815,6 +828,10 @@ static int __iomap_write_begin(const struct iomap_iter *iter,
else
status = iomap_bio_read_folio_range_sync(iter,
folio, block_start, plen);
+ if (status < 0)
+ fserror_report_io(iter->inode,
+ FSERR_BUFFERED_READ, pos,
+ len, status, GFP_NOFS);
if (status)
return status;
}
@@ -1825,6 +1842,7 @@ int iomap_writeback_folio(struct iomap_writepage_ctx *wpc, struct folio *folio)
u64 pos = folio_pos(folio);
u64 end_pos = pos + folio_size(folio);
u64 end_aligned = 0;
+ loff_t orig_pos = pos;
size_t bytes_submitted = 0;
int error = 0;
u32 rlen;
@@ -1868,6 +1886,9 @@ int iomap_writeback_folio(struct iomap_writepage_ctx *wpc, struct folio *folio)
if (bytes_submitted)
wpc->nr_folios++;
+ if (error && pos > orig_pos)
+ fserror_report_io(inode, FSERR_BUFFERED_WRITE, orig_pos, 0,
+ error, GFP_NOFS);
/*
* We can have dirty bits set past end of file in page_mkwrite path
diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
index 8e273408453a9c..a06c73eaa8901b 100644
--- a/fs/iomap/direct-io.c
+++ b/fs/iomap/direct-io.c
@@ -7,6 +7,7 @@
#include <linux/pagemap.h>
#include <linux/iomap.h>
#include <linux/task_io_accounting_ops.h>
+#include <linux/fserror.h>
#include "internal.h"
#include "trace.h"
@@ -78,6 +79,13 @@ static void iomap_dio_submit_bio(const struct iomap_iter *iter,
}
}
+static inline enum fserror_type iomap_dio_err_type(const struct iomap_dio *dio)
+{
+ if (dio->flags & IOMAP_DIO_WRITE)
+ return FSERR_DIRECTIO_WRITE;
+ return FSERR_DIRECTIO_READ;
+}
+
ssize_t iomap_dio_complete(struct iomap_dio *dio)
{
const struct iomap_dio_ops *dops = dio->dops;
@@ -87,6 +95,10 @@ ssize_t iomap_dio_complete(struct iomap_dio *dio)
if (dops && dops->end_io)
ret = dops->end_io(iocb, dio->size, ret, dio->flags);
+ if (dio->error)
+ fserror_report_io(file_inode(iocb->ki_filp),
+ iomap_dio_err_type(dio), offset, dio->size,
+ dio->error, GFP_NOFS);
if (likely(!ret)) {
ret = dio->size;
diff --git a/fs/iomap/ioend.c b/fs/iomap/ioend.c
index 86f44922ed3b6a..5b27ee98896707 100644
--- a/fs/iomap/ioend.c
+++ b/fs/iomap/ioend.c
@@ -6,6 +6,7 @@
#include <linux/list_sort.h>
#include <linux/pagemap.h>
#include <linux/writeback.h>
+#include <linux/fserror.h>
#include "internal.h"
#include "trace.h"
@@ -55,6 +56,11 @@ static u32 iomap_finish_ioend_buffered(struct iomap_ioend *ioend)
/* walk all folios in bio, ending page IO on them */
bio_for_each_folio_all(fi, bio) {
+ if (ioend->io_error)
+ fserror_report_io(inode, FSERR_BUFFERED_WRITE,
+ folio_pos(fi.folio) + fi.offset,
+ fi.length, ioend->io_error,
+ GFP_ATOMIC);
iomap_finish_folio_write(inode, fi.folio, fi.length);
folio_count++;
}
^ permalink raw reply related [flat|nested] 21+ messages in thread* [PATCH 4/6] xfs: report fs metadata errors via fsnotify
2026-01-13 0:31 [PATCHSET v5] fs: generic file IO error reporting Darrick J. Wong
` (2 preceding siblings ...)
2026-01-13 0:31 ` [PATCH 3/6] iomap: report file I/O errors to the VFS Darrick J. Wong
@ 2026-01-13 0:31 ` Darrick J. Wong
2026-01-13 0:32 ` [PATCH 5/6] xfs: translate fsdax media errors into file "data lost" errors when convenient Darrick J. Wong
` (2 subsequent siblings)
6 siblings, 0 replies; 21+ messages in thread
From: Darrick J. Wong @ 2026-01-13 0:31 UTC (permalink / raw)
To: djwong, brauner
Cc: hch, linux-xfs, jack, linux-ext4, linux-fsdevel, gabriel, hch,
amir73il
From: Darrick J. Wong <djwong@kernel.org>
Report filesystem corruption problems to the fserror helpers so that
fsnotify can also convey metadata problems to userspace.
Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
fs/xfs/xfs_fsops.c | 4 ++++
fs/xfs/xfs_health.c | 14 ++++++++++++++
2 files changed, 18 insertions(+)
diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
index 0ada735693945c..b7c21f68edc78d 100644
--- a/fs/xfs/xfs_fsops.c
+++ b/fs/xfs/xfs_fsops.c
@@ -26,6 +26,8 @@
#include "xfs_rtrefcount_btree.h"
#include "xfs_metafile.h"
+#include <linux/fserror.h>
+
/*
* Write new AG headers to disk. Non-transactional, but need to be
* written and completed prior to the growfs transaction being logged.
@@ -540,6 +542,8 @@ xfs_do_force_shutdown(
"Please unmount the filesystem and rectify the problem(s)");
if (xfs_error_level >= XFS_ERRLEVEL_HIGH)
xfs_stack_trace();
+
+ fserror_report_shutdown(mp->m_super, GFP_KERNEL);
}
/*
diff --git a/fs/xfs/xfs_health.c b/fs/xfs/xfs_health.c
index 3c1557fb1cf083..fbb8886c72fe5e 100644
--- a/fs/xfs/xfs_health.c
+++ b/fs/xfs/xfs_health.c
@@ -20,6 +20,8 @@
#include "xfs_quota_defs.h"
#include "xfs_rtgroup.h"
+#include <linux/fserror.h>
+
static void
xfs_health_unmount_group(
struct xfs_group *xg,
@@ -111,6 +113,8 @@ xfs_fs_mark_sick(
spin_lock(&mp->m_sb_lock);
mp->m_fs_sick |= mask;
spin_unlock(&mp->m_sb_lock);
+
+ fserror_report_metadata(mp->m_super, -EFSCORRUPTED, GFP_NOFS);
}
/* Mark per-fs metadata as having been checked and found unhealthy by fsck. */
@@ -126,6 +130,8 @@ xfs_fs_mark_corrupt(
mp->m_fs_sick |= mask;
mp->m_fs_checked |= mask;
spin_unlock(&mp->m_sb_lock);
+
+ fserror_report_metadata(mp->m_super, -EFSCORRUPTED, GFP_NOFS);
}
/* Mark a per-fs metadata healed. */
@@ -198,6 +204,8 @@ xfs_group_mark_sick(
spin_lock(&xg->xg_state_lock);
xg->xg_sick |= mask;
spin_unlock(&xg->xg_state_lock);
+
+ fserror_report_metadata(xg->xg_mount->m_super, -EFSCORRUPTED, GFP_NOFS);
}
/*
@@ -215,6 +223,8 @@ xfs_group_mark_corrupt(
xg->xg_sick |= mask;
xg->xg_checked |= mask;
spin_unlock(&xg->xg_state_lock);
+
+ fserror_report_metadata(xg->xg_mount->m_super, -EFSCORRUPTED, GFP_NOFS);
}
/*
@@ -287,6 +297,8 @@ xfs_inode_mark_sick(
spin_lock(&VFS_I(ip)->i_lock);
inode_state_clear(VFS_I(ip), I_DONTCACHE);
spin_unlock(&VFS_I(ip)->i_lock);
+
+ fserror_report_file_metadata(VFS_I(ip), -EFSCORRUPTED, GFP_NOFS);
}
/* Mark inode metadata as having been checked and found unhealthy by fsck. */
@@ -311,6 +323,8 @@ xfs_inode_mark_corrupt(
spin_lock(&VFS_I(ip)->i_lock);
inode_state_clear(VFS_I(ip), I_DONTCACHE);
spin_unlock(&VFS_I(ip)->i_lock);
+
+ fserror_report_file_metadata(VFS_I(ip), -EFSCORRUPTED, GFP_NOFS);
}
/* Mark parts of an inode healed. */
^ permalink raw reply related [flat|nested] 21+ messages in thread* [PATCH 5/6] xfs: translate fsdax media errors into file "data lost" errors when convenient
2026-01-13 0:31 [PATCHSET v5] fs: generic file IO error reporting Darrick J. Wong
` (3 preceding siblings ...)
2026-01-13 0:31 ` [PATCH 4/6] xfs: report fs metadata errors via fsnotify Darrick J. Wong
@ 2026-01-13 0:32 ` Darrick J. Wong
2026-01-13 0:32 ` [PATCH 6/6] ext4: convert to new fserror helpers Darrick J. Wong
2026-01-13 8:58 ` [PATCHSET v5] fs: generic file IO error reporting Christian Brauner
6 siblings, 0 replies; 21+ messages in thread
From: Darrick J. Wong @ 2026-01-13 0:32 UTC (permalink / raw)
To: djwong, brauner
Cc: hch, linux-xfs, jack, linux-ext4, linux-fsdevel, gabriel, hch,
amir73il
From: Darrick J. Wong <djwong@kernel.org>
Translate fsdax persistent failure notifications into file data loss
events when it's convenient, aka when the inode is already incore.
Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
fs/xfs/xfs_notify_failure.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/fs/xfs/xfs_notify_failure.c b/fs/xfs/xfs_notify_failure.c
index b1767288994206..6d5002413c2cb4 100644
--- a/fs/xfs/xfs_notify_failure.c
+++ b/fs/xfs/xfs_notify_failure.c
@@ -26,6 +26,7 @@
#include <linux/mm.h>
#include <linux/dax.h>
#include <linux/fs.h>
+#include <linux/fserror.h>
struct xfs_failure_info {
xfs_agblock_t startblock;
@@ -116,6 +117,9 @@ xfs_dax_failure_fn(
invalidate_inode_pages2_range(mapping, pgoff,
pgoff + pgcnt - 1);
+ fserror_report_data_lost(VFS_I(ip), (u64)pgoff << PAGE_SHIFT,
+ (u64)pgcnt << PAGE_SHIFT, GFP_NOFS);
+
xfs_irele(ip);
return error;
}
^ permalink raw reply related [flat|nested] 21+ messages in thread* [PATCH 6/6] ext4: convert to new fserror helpers
2026-01-13 0:31 [PATCHSET v5] fs: generic file IO error reporting Darrick J. Wong
` (4 preceding siblings ...)
2026-01-13 0:32 ` [PATCH 5/6] xfs: translate fsdax media errors into file "data lost" errors when convenient Darrick J. Wong
@ 2026-01-13 0:32 ` Darrick J. Wong
2026-01-13 0:56 ` Gabriel Krisman Bertazi
2026-01-15 15:29 ` Theodore Tso
2026-01-13 8:58 ` [PATCHSET v5] fs: generic file IO error reporting Christian Brauner
6 siblings, 2 replies; 21+ messages in thread
From: Darrick J. Wong @ 2026-01-13 0:32 UTC (permalink / raw)
To: djwong, brauner
Cc: hch, jack, linux-xfs, jack, linux-ext4, linux-fsdevel, gabriel,
hch, amir73il
From: Darrick J. Wong <djwong@kernel.org>
Use the new fserror functions to report metadata errors to fsnotify.
Note that ext4 inconsistently passes around negative and positive error
numbers all over the codebase, so we force them all to negative for
consistency in what we report to fserror, and fserror ensures that only
positive error numbers are passed to fanotify, per the fanotify(7)
manpage.
Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
---
fs/ext4/ioctl.c | 2 ++
fs/ext4/super.c | 13 +++++++++----
2 files changed, 11 insertions(+), 4 deletions(-)
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index 7ce0fc40aec2fb..ea26cd03d3ce28 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -26,6 +26,7 @@
#include <linux/fsmap.h>
#include "fsmap.h"
#include <trace/events/ext4.h>
+#include <linux/fserror.h>
typedef void ext4_update_sb_callback(struct ext4_sb_info *sbi,
struct ext4_super_block *es,
@@ -844,6 +845,7 @@ int ext4_force_shutdown(struct super_block *sb, u32 flags)
return -EINVAL;
}
clear_opt(sb, DISCARD);
+ fserror_report_shutdown(sb, GFP_KERNEL);
return 0;
}
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 87205660c5d026..a6241ffb8639c3 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -48,6 +48,7 @@
#include <linux/fsnotify.h>
#include <linux/fs_context.h>
#include <linux/fs_parser.h>
+#include <linux/fserror.h>
#include "ext4.h"
#include "ext4_extents.h" /* Needed for trace points definition */
@@ -824,7 +825,8 @@ void __ext4_error(struct super_block *sb, const char *function,
sb->s_id, function, line, current->comm, &vaf);
va_end(args);
}
- fsnotify_sb_error(sb, NULL, error ? error : EFSCORRUPTED);
+ fserror_report_metadata(sb, error ? -abs(error) : -EFSCORRUPTED,
+ GFP_ATOMIC);
ext4_handle_error(sb, force_ro, error, 0, block, function, line);
}
@@ -856,7 +858,9 @@ void __ext4_error_inode(struct inode *inode, const char *function,
current->comm, &vaf);
va_end(args);
}
- fsnotify_sb_error(inode->i_sb, inode, error ? error : EFSCORRUPTED);
+ fserror_report_file_metadata(inode,
+ error ? -abs(error) : -EFSCORRUPTED,
+ GFP_ATOMIC);
ext4_handle_error(inode->i_sb, false, error, inode->i_ino, block,
function, line);
@@ -896,7 +900,7 @@ void __ext4_error_file(struct file *file, const char *function,
current->comm, path, &vaf);
va_end(args);
}
- fsnotify_sb_error(inode->i_sb, inode, EFSCORRUPTED);
+ fserror_report_file_metadata(inode, -EFSCORRUPTED, GFP_ATOMIC);
ext4_handle_error(inode->i_sb, false, EFSCORRUPTED, inode->i_ino, block,
function, line);
@@ -965,7 +969,8 @@ void __ext4_std_error(struct super_block *sb, const char *function,
printk(KERN_CRIT "EXT4-fs error (device %s) in %s:%d: %s\n",
sb->s_id, function, line, errstr);
}
- fsnotify_sb_error(sb, NULL, errno ? errno : EFSCORRUPTED);
+ fserror_report_metadata(sb, errno ? -abs(errno) : -EFSCORRUPTED,
+ GFP_ATOMIC);
ext4_handle_error(sb, false, -errno, 0, 0, function, line);
}
^ permalink raw reply related [flat|nested] 21+ messages in thread* Re: [PATCH 6/6] ext4: convert to new fserror helpers
2026-01-13 0:32 ` [PATCH 6/6] ext4: convert to new fserror helpers Darrick J. Wong
@ 2026-01-13 0:56 ` Gabriel Krisman Bertazi
2026-01-13 1:26 ` Darrick J. Wong
2026-01-15 15:29 ` Theodore Tso
1 sibling, 1 reply; 21+ messages in thread
From: Gabriel Krisman Bertazi @ 2026-01-13 0:56 UTC (permalink / raw)
To: Darrick J. Wong
Cc: brauner, hch, jack, linux-xfs, linux-ext4, linux-fsdevel,
amir73il
"Darrick J. Wong" <djwong@kernel.org> writes:
> From: Darrick J. Wong <djwong@kernel.org>
>
> Use the new fserror functions to report metadata errors to fsnotify.
> Note that ext4 inconsistently passes around negative and positive error
> numbers all over the codebase, so we force them all to negative for
> consistency in what we report to fserror, and fserror ensures that only
> positive error numbers are passed to fanotify, per the fanotify(7)
> manpage.
>
> Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Jan Kara <jack@suse.cz>
> ---
> fs/ext4/ioctl.c | 2 ++
> fs/ext4/super.c | 13 +++++++++----
> 2 files changed, 11 insertions(+), 4 deletions(-)
>
>
> diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
> index 7ce0fc40aec2fb..ea26cd03d3ce28 100644
> --- a/fs/ext4/ioctl.c
> +++ b/fs/ext4/ioctl.c
> @@ -26,6 +26,7 @@
> #include <linux/fsmap.h>
> #include "fsmap.h"
> #include <trace/events/ext4.h>
> +#include <linux/fserror.h>
>
> typedef void ext4_update_sb_callback(struct ext4_sb_info *sbi,
> struct ext4_super_block *es,
> @@ -844,6 +845,7 @@ int ext4_force_shutdown(struct super_block *sb, u32 flags)
> return -EINVAL;
> }
> clear_opt(sb, DISCARD);
> + fserror_report_shutdown(sb, GFP_KERNEL);
> return 0;
> }
>
> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index 87205660c5d026..a6241ffb8639c3 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -48,6 +48,7 @@
> #include <linux/fsnotify.h>
> #include <linux/fs_context.h>
> #include <linux/fs_parser.h>
> +#include <linux/fserror.h>
>
> #include "ext4.h"
> #include "ext4_extents.h" /* Needed for trace points definition */
> @@ -824,7 +825,8 @@ void __ext4_error(struct super_block *sb, const char *function,
> sb->s_id, function, line, current->comm, &vaf);
> va_end(args);
> }
> - fsnotify_sb_error(sb, NULL, error ? error : EFSCORRUPTED);
> + fserror_report_metadata(sb, error ? -abs(error) : -EFSCORRUPTED,
> + GFP_ATOMIC);
>
> ext4_handle_error(sb, force_ro, error, 0, block, function, line);
> }
> @@ -856,7 +858,9 @@ void __ext4_error_inode(struct inode *inode, const char *function,
> current->comm, &vaf);
> va_end(args);
> }
> - fsnotify_sb_error(inode->i_sb, inode, error ? error : EFSCORRUPTED);
> + fserror_report_file_metadata(inode,
> + error ? -abs(error) : -EFSCORRUPTED,
> + GFP_ATOMIC);
>
> ext4_handle_error(inode->i_sb, false, error, inode->i_ino, block,
> function, line);
> @@ -896,7 +900,7 @@ void __ext4_error_file(struct file *file, const char *function,
> current->comm, path, &vaf);
> va_end(args);
> }
> - fsnotify_sb_error(inode->i_sb, inode, EFSCORRUPTED);
> + fserror_report_file_metadata(inode, -EFSCORRUPTED, GFP_ATOMIC);
>
> ext4_handle_error(inode->i_sb, false, EFSCORRUPTED, inode->i_ino, block,
> function, line);
> @@ -965,7 +969,8 @@ void __ext4_std_error(struct super_block *sb, const char *function,
> printk(KERN_CRIT "EXT4-fs error (device %s) in %s:%d: %s\n",
> sb->s_id, function, line, errstr);
> }
> - fsnotify_sb_error(sb, NULL, errno ? errno : EFSCORRUPTED);
> + fserror_report_metadata(sb, errno ? -abs(errno) : -EFSCORRUPTED,
> + GFP_ATOMIC);
>
> ext4_handle_error(sb, false, -errno, 0, 0, function, line);
> }
>
Perhaps also delete fsnotify_sb_error after this patch since it is now
implemented by fserror_worker and, if I follow correctly, we don't want
it to be called without the shutdown protection mechanism.
--
Gabriel Krisman Bertazi
^ permalink raw reply [flat|nested] 21+ messages in thread
* Re: [PATCH 6/6] ext4: convert to new fserror helpers
2026-01-13 0:56 ` Gabriel Krisman Bertazi
@ 2026-01-13 1:26 ` Darrick J. Wong
0 siblings, 0 replies; 21+ messages in thread
From: Darrick J. Wong @ 2026-01-13 1:26 UTC (permalink / raw)
To: Gabriel Krisman Bertazi
Cc: brauner, hch, jack, linux-xfs, linux-ext4, linux-fsdevel,
amir73il
On Mon, Jan 12, 2026 at 07:56:09PM -0500, Gabriel Krisman Bertazi wrote:
> "Darrick J. Wong" <djwong@kernel.org> writes:
>
> > From: Darrick J. Wong <djwong@kernel.org>
> >
> > Use the new fserror functions to report metadata errors to fsnotify.
> > Note that ext4 inconsistently passes around negative and positive error
> > numbers all over the codebase, so we force them all to negative for
> > consistency in what we report to fserror, and fserror ensures that only
> > positive error numbers are passed to fanotify, per the fanotify(7)
> > manpage.
> >
> > Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
> > Reviewed-by: Christoph Hellwig <hch@lst.de>
> > Reviewed-by: Jan Kara <jack@suse.cz>
> > ---
> > fs/ext4/ioctl.c | 2 ++
> > fs/ext4/super.c | 13 +++++++++----
> > 2 files changed, 11 insertions(+), 4 deletions(-)
> >
> >
> > diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
> > index 7ce0fc40aec2fb..ea26cd03d3ce28 100644
> > --- a/fs/ext4/ioctl.c
> > +++ b/fs/ext4/ioctl.c
> > @@ -26,6 +26,7 @@
> > #include <linux/fsmap.h>
> > #include "fsmap.h"
> > #include <trace/events/ext4.h>
> > +#include <linux/fserror.h>
> >
> > typedef void ext4_update_sb_callback(struct ext4_sb_info *sbi,
> > struct ext4_super_block *es,
> > @@ -844,6 +845,7 @@ int ext4_force_shutdown(struct super_block *sb, u32 flags)
> > return -EINVAL;
> > }
> > clear_opt(sb, DISCARD);
> > + fserror_report_shutdown(sb, GFP_KERNEL);
> > return 0;
> > }
> >
> > diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> > index 87205660c5d026..a6241ffb8639c3 100644
> > --- a/fs/ext4/super.c
> > +++ b/fs/ext4/super.c
> > @@ -48,6 +48,7 @@
> > #include <linux/fsnotify.h>
> > #include <linux/fs_context.h>
> > #include <linux/fs_parser.h>
> > +#include <linux/fserror.h>
> >
> > #include "ext4.h"
> > #include "ext4_extents.h" /* Needed for trace points definition */
> > @@ -824,7 +825,8 @@ void __ext4_error(struct super_block *sb, const char *function,
> > sb->s_id, function, line, current->comm, &vaf);
> > va_end(args);
> > }
> > - fsnotify_sb_error(sb, NULL, error ? error : EFSCORRUPTED);
> > + fserror_report_metadata(sb, error ? -abs(error) : -EFSCORRUPTED,
> > + GFP_ATOMIC);
> >
> > ext4_handle_error(sb, force_ro, error, 0, block, function, line);
> > }
> > @@ -856,7 +858,9 @@ void __ext4_error_inode(struct inode *inode, const char *function,
> > current->comm, &vaf);
> > va_end(args);
> > }
> > - fsnotify_sb_error(inode->i_sb, inode, error ? error : EFSCORRUPTED);
> > + fserror_report_file_metadata(inode,
> > + error ? -abs(error) : -EFSCORRUPTED,
> > + GFP_ATOMIC);
> >
> > ext4_handle_error(inode->i_sb, false, error, inode->i_ino, block,
> > function, line);
> > @@ -896,7 +900,7 @@ void __ext4_error_file(struct file *file, const char *function,
> > current->comm, path, &vaf);
> > va_end(args);
> > }
> > - fsnotify_sb_error(inode->i_sb, inode, EFSCORRUPTED);
> > + fserror_report_file_metadata(inode, -EFSCORRUPTED, GFP_ATOMIC);
> >
> > ext4_handle_error(inode->i_sb, false, EFSCORRUPTED, inode->i_ino, block,
> > function, line);
> > @@ -965,7 +969,8 @@ void __ext4_std_error(struct super_block *sb, const char *function,
> > printk(KERN_CRIT "EXT4-fs error (device %s) in %s:%d: %s\n",
> > sb->s_id, function, line, errstr);
> > }
> > - fsnotify_sb_error(sb, NULL, errno ? errno : EFSCORRUPTED);
> > + fserror_report_metadata(sb, errno ? -abs(errno) : -EFSCORRUPTED,
> > + GFP_ATOMIC);
> >
> > ext4_handle_error(sb, false, -errno, 0, 0, function, line);
> > }
> >
>
> Perhaps also delete fsnotify_sb_error after this patch since it is now
> implemented by fserror_worker and, if I follow correctly, we don't want
> it to be called without the shutdown protection mechanism.
<nod> I was planning to ask Linus if I could do that as a treewide
cleanup at the end of the whichever merge window integrates this, just
in case someone else adds a fsnotify_sb_error call to their filesystem
during that same merge window.
--D
> --
> Gabriel Krisman Bertazi
>
^ permalink raw reply [flat|nested] 21+ messages in thread
* Re: [PATCH 6/6] ext4: convert to new fserror helpers
2026-01-13 0:32 ` [PATCH 6/6] ext4: convert to new fserror helpers Darrick J. Wong
2026-01-13 0:56 ` Gabriel Krisman Bertazi
@ 2026-01-15 15:29 ` Theodore Tso
1 sibling, 0 replies; 21+ messages in thread
From: Theodore Tso @ 2026-01-15 15:29 UTC (permalink / raw)
To: Darrick J. Wong
Cc: brauner, hch, jack, linux-xfs, linux-ext4, linux-fsdevel, gabriel,
amir73il
On Mon, Jan 12, 2026 at 04:32:27PM -0800, Darrick J. Wong wrote:
> From: Darrick J. Wong <djwong@kernel.org>
>
> Use the new fserror functions to report metadata errors to fsnotify.
> Note that ext4 inconsistently passes around negative and positive error
> numbers all over the codebase, so we force them all to negative for
> consistency in what we report to fserror, and fserror ensures that only
> positive error numbers are passed to fanotify, per the fanotify(7)
> manpage.
>
> Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Theodore Ts'o <tytso@mit.edu>
^ permalink raw reply [flat|nested] 21+ messages in thread
* Re: [PATCHSET v5] fs: generic file IO error reporting
2026-01-13 0:31 [PATCHSET v5] fs: generic file IO error reporting Darrick J. Wong
` (5 preceding siblings ...)
2026-01-13 0:32 ` [PATCH 6/6] ext4: convert to new fserror helpers Darrick J. Wong
@ 2026-01-13 8:58 ` Christian Brauner
6 siblings, 0 replies; 21+ messages in thread
From: Christian Brauner @ 2026-01-13 8:58 UTC (permalink / raw)
To: Darrick J. Wong
Cc: Christian Brauner, linux-api, jack, hch, linux-xfs, linux-ext4,
linux-fsdevel, gabriel, amir73il, Gao Xiang
On Mon, 12 Jan 2026 16:31:03 -0800, Darrick J. Wong wrote:
> 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.
>
> [...]
Applied to the vfs-7.0.fserror branch of the vfs/vfs.git tree.
Patches in the vfs-7.0.fserror branch should appear in linux-next soon.
Please report any outstanding bugs that were missed during review in a
new review to the original patch series allowing us to drop it.
It's encouraged to provide Acked-bys and Reviewed-bys even though the
patch has now been applied. If possible patch trailers will be updated.
Note that commit hashes shown below are subject to change due to rebase,
trailer updates or similar. If in doubt, please check the listed branch.
tree: https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git
branch: vfs-7.0.fserror
[1/6] uapi: promote EFSCORRUPTED and EUCLEAN to errno.h
https://git.kernel.org/vfs/vfs/c/602544773763
[2/6] fs: report filesystem and file I/O errors to fsnotify
https://git.kernel.org/vfs/vfs/c/21945e6cb516
[3/6] iomap: report file I/O errors to the VFS
https://git.kernel.org/vfs/vfs/c/a9d573ee88af
[4/6] xfs: report fs metadata errors via fsnotify
https://git.kernel.org/vfs/vfs/c/efd87a100729
[5/6] xfs: translate fsdax media errors into file "data lost" errors when convenient
https://git.kernel.org/vfs/vfs/c/94503211d2fd
[6/6] ext4: convert to new fserror helpers
https://git.kernel.org/vfs/vfs/c/81d2e13a57c9
^ permalink raw reply [flat|nested] 21+ messages in thread
* [PATCH 2/6] fs: report filesystem and file I/O errors to fsnotify
2025-12-18 2:02 [PATCHSET V4 1/2] " Darrick J. Wong
@ 2025-12-18 2:03 ` Darrick J. Wong
2025-12-18 5:21 ` Christoph Hellwig
2025-12-22 15:36 ` Jan Kara
0 siblings, 2 replies; 21+ messages in thread
From: Darrick J. Wong @ 2025-12-18 2:03 UTC (permalink / raw)
To: brauner, djwong
Cc: hch, linux-ext4, jack, linux-xfs, linux-fsdevel, gabriel, hch,
amir73il
From: Darrick J. Wong <djwong@kernel.org>
Create some wrapper code around struct super_block so that filesystems
have a standard way to queue filesystem metadata and file I/O error
reports to have them sent to fsnotify.
If a filesystem wants to provide an error number, it must supply only
negative error numbers. These are stored internally as negative
numbers, but they are converted to positive error numbers before being
passed to fanotify, per the fanotify(7) manpage. Implementations of
super_operations::report_error are passed the raw internal event data.
Note that we have to play some shenanigans with mempools and queue_work
so that the error handling doesn't happen outside of process context,
and the event handler functions (both ->report_error and fsnotify) can
handle file I/O error messages without having to worry about whatever
locks might be held. This asynchronicity requires that unmount wait for
pending events to clear.
Add a new callback to the superblock operations structure so that
filesystem drivers can themselves respond to file I/O errors if they so
desire. This will be used for an upcoming self-healing patchset for
XFS.
Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
---
include/linux/fs/super_types.h | 7 ++
include/linux/fserror.h | 93 ++++++++++++++++++++++
fs/Makefile | 2
fs/fserror.c | 168 ++++++++++++++++++++++++++++++++++++++++
fs/super.c | 3 +
5 files changed, 272 insertions(+), 1 deletion(-)
create mode 100644 include/linux/fserror.h
create mode 100644 fs/fserror.c
diff --git a/include/linux/fs/super_types.h b/include/linux/fs/super_types.h
index 6bd3009e09b3b8..c01383dfb99f23 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 00000000000000..95c813fef58d2f
--- /dev/null
+++ b/include/linux/fserror.h
@@ -0,0 +1,93 @@
+/* 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__
+
+static inline void fserror_mount(struct super_block *sb)
+{
+ /*
+ * The pending error counter is biased by 1 so that we don't wake_var
+ * until we're actually trying to unmount.
+ */
+ refcount_set(&sb->s_pending_errors, 1);
+}
+
+static inline void fserror_unmount(struct super_block *sb)
+{
+ /*
+ * If we don't drop the pending error count to zero, then wait for it
+ * to drop below 1, which means that the pending errors cleared or
+ * that we saturated the system with 1 billion+ concurrent events.
+ */
+ if (!refcount_dec_and_test(&sb->s_pending_errors))
+ wait_var_event(&sb->s_pending_errors,
+ refcount_read(&sb->s_pending_errors) < 1);
+}
+
+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/fs/Makefile b/fs/Makefile
index a04274a3c85420..f238cc5ea2e9d7 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -16,7 +16,7 @@ obj-y := open.o read_write.o file_table.o super.o \
stack.o fs_struct.o statfs.o fs_pin.o nsfs.o \
fs_dirent.o fs_context.o fs_parser.o fsopen.o init.o \
kernel_read_file.o mnt_idmapping.o remap_range.o pidfs.o \
- file_attr.o
+ file_attr.o fserror.o
obj-$(CONFIG_BUFFER_HEAD) += buffer.o mpage.o
obj-$(CONFIG_PROC_FS) += proc_namespace.o
diff --git a/fs/fserror.c b/fs/fserror.c
new file mode 100644
index 00000000000000..1a5539d1edef93
--- /dev/null
+++ b/fs/fserror.c
@@ -0,0 +1,168 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2025 Oracle. All Rights Reserved.
+ * Author: Darrick J. Wong <djwong@kernel.org>
+ */
+#include <linux/fs.h>
+#include <linux/fsnotify.h>
+#include <linux/mempool.h>
+#include <linux/fserror.h>
+
+#define FSERROR_DEFAULT_EVENT_POOL_SIZE (32)
+
+static struct mempool fserror_events_pool;
+
+static inline void fserror_pending_dec(struct super_block *sb)
+{
+ if (refcount_dec_and_test(&sb->s_pending_errors))
+ wake_up_var(&sb->s_pending_errors);
+}
+
+static inline void fserror_free_event(struct fserror_event *event)
+{
+ fserror_pending_dec(event->sb);
+ mempool_free(event, &fserror_events_pool);
+}
+
+static void fserror_worker(struct work_struct *work)
+{
+ struct fserror_event *event =
+ container_of(work, struct fserror_event, work);
+ struct super_block *sb = event->sb;
+
+ if (sb->s_flags & SB_ACTIVE) {
+ struct fs_error_report report = {
+ /* send positive error number to userspace */
+ .error = -event->error,
+ .inode = event->inode,
+ .sb = event->sb,
+ };
+
+ if (sb->s_op->report_error)
+ sb->s_op->report_error(event);
+
+ fsnotify(FS_ERROR, &report, FSNOTIFY_EVENT_ERROR, NULL, NULL,
+ NULL, 0);
+ }
+
+ iput(event->inode);
+ fserror_free_event(event);
+}
+
+static inline struct fserror_event *fserror_alloc_event(struct super_block *sb,
+ gfp_t gfp_flags)
+{
+ struct fserror_event *event = NULL;
+
+ /*
+ * If pending_errors already reached zero or is no longer active,
+ * the superblock is being deactivated so there's no point in
+ * continuing.
+ */
+ if (!refcount_inc_not_zero(&sb->s_pending_errors))
+ return NULL;
+ if (!(sb->s_flags & SB_ACTIVE))
+ goto out_pending;
+
+ event = mempool_alloc(&fserror_events_pool, gfp_flags);
+ if (!event)
+ goto out_pending;
+
+ /* mempool_alloc doesn't support GFP_ZERO */
+ memset(event, 0, sizeof(*event));
+ event->sb = sb;
+ INIT_WORK(&event->work, fserror_worker);
+
+ return event;
+
+out_pending:
+ fserror_pending_dec(sb);
+ return NULL;
+}
+
+/**
+ * fserror_report - report a filesystem error of some kind
+ *
+ * Report details of a filesystem error to the super_operations::report_error
+ * callback if present; and to fsnotify for distribution to userspace. @sb,
+ * @gfp, @type, and @error must all be specified. For file I/O errors, the
+ * @inode, @pos, and @len fields must also be specified. For file metadata
+ * errors, @inode must be specified. If @inode is not NULL, then @inode->i_sb
+ * must point to @sb.
+ *
+ * Reporting work is deferred to a workqueue to ensure that ->report_error is
+ * called from process context without any locks held. An active reference to
+ * the inode is maintained until event handling is complete, and unmount will
+ * wait for queued events to drain.
+ *
+ * @sb: superblock of the filesystem
+ * @inode: inode within that filesystem, if applicable
+ * @type: type of error encountered
+ * @pos: start of inode range affected, if applicable
+ * @len: length of inode range affected, if applicable
+ * @error: error number encountered, must be negative
+ * @gfp: memory allocation flags for conveying the event to a worker,
+ * since this function can be called from atomic contexts
+ */
+void fserror_report(struct super_block *sb, struct inode *inode,
+ enum fserror_type type, loff_t pos, u64 len, int error,
+ gfp_t gfp)
+{
+ struct fserror_event *event;
+
+ /* sb and inode must be from the same filesystem */
+ WARN_ON_ONCE(inode && inode->i_sb != sb);
+
+ /* error number must be negative */
+ WARN_ON_ONCE(error >= 0);
+
+ event = fserror_alloc_event(sb, gfp);
+ if (!event)
+ goto lost;
+
+ event->type = type;
+ event->pos = pos;
+ event->len = len;
+ event->error = error;
+
+ /*
+ * Can't iput from non-sleeping context, so grabbing another reference
+ * to the inode must be the last thing before submitting the event.
+ */
+ if (inode) {
+ event->inode = igrab(inode);
+ if (!event->inode)
+ goto lost_event;
+ }
+
+ /*
+ * Use schedule_work here even if we're already in process context so
+ * that fsnotify and super_operations::report_error implementations are
+ * guaranteed to run in process context without any locks held. Since
+ * errors are supposed to be rare, the overhead shouldn't kill us any
+ * more than the failing device will.
+ */
+ schedule_work(&event->work);
+ return;
+
+lost_event:
+ fserror_free_event(event);
+lost:
+ if (inode)
+ pr_err_ratelimited(
+ "%s: lost file I/O error report for ino %lu type %u pos 0x%llx len 0x%llx error %d",
+ sb->s_id, inode->i_ino, type, pos, len, error);
+ else
+ pr_err_ratelimited(
+ "%s: lost filesystem error report for type %u error %d",
+ sb->s_id, type, error);
+}
+EXPORT_SYMBOL_GPL(fserror_report);
+
+static int __init fserror_init(void)
+{
+ return mempool_init_kmalloc_pool(&fserror_events_pool,
+ FSERROR_DEFAULT_EVENT_POOL_SIZE,
+ sizeof(struct fserror_event));
+}
+fs_initcall(fserror_init);
diff --git a/fs/super.c b/fs/super.c
index 3d85265d14001d..b13c1fd6a6f422 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -36,6 +36,7 @@
#include <linux/lockdep.h>
#include <linux/user_namespace.h>
#include <linux/fs_context.h>
+#include <linux/fserror.h>
#include <uapi/linux/mount.h>
#include "internal.h"
@@ -363,6 +364,7 @@ static struct super_block *alloc_super(struct file_system_type *type, int flags,
spin_lock_init(&s->s_inode_list_lock);
INIT_LIST_HEAD(&s->s_inodes_wb);
spin_lock_init(&s->s_inode_wblist_lock);
+ fserror_mount(s);
s->s_count = 1;
atomic_set(&s->s_active, 1);
@@ -622,6 +624,7 @@ void generic_shutdown_super(struct super_block *sb)
sync_filesystem(sb);
sb->s_flags &= ~SB_ACTIVE;
+ fserror_unmount(sb);
cgroup_writeback_umount(sb);
/* Evict all inodes with zero refcount. */
^ permalink raw reply related [flat|nested] 21+ messages in thread* Re: [PATCH 2/6] fs: report filesystem and file I/O errors to fsnotify
2025-12-18 2:03 ` [PATCH 2/6] fs: report filesystem and file I/O errors to fsnotify Darrick J. Wong
@ 2025-12-18 5:21 ` Christoph Hellwig
2025-12-18 18:44 ` Darrick J. Wong
2025-12-22 15:36 ` Jan Kara
1 sibling, 1 reply; 21+ messages in thread
From: Christoph Hellwig @ 2025-12-18 5:21 UTC (permalink / raw)
To: Darrick J. Wong
Cc: brauner, linux-ext4, jack, linux-xfs, linux-fsdevel, gabriel,
amir73il
> long s_min_writeback_pages;
> +
> + /* number of fserrors that are being sent to fsnotify/filesystems */
> + refcount_t s_pending_errors;
Use the same tab-alignment as the fields above? Also is this really
a refcount? It's a counter, but not really a reference? I guess
that doesn't matter too much.
> +static inline void fserror_unmount(struct super_block *sb)
> +{
> + /*
> + * If we don't drop the pending error count to zero, then wait for it
> + * to drop below 1, which means that the pending errors cleared or
> + * that we saturated the system with 1 billion+ concurrent events.
> + */
> + if (!refcount_dec_and_test(&sb->s_pending_errors))
> + wait_var_event(&sb->s_pending_errors,
> + refcount_read(&sb->s_pending_errors) < 1);
> +}
Should this be out of line?
> +/**
> + * fserror_report - report a filesystem error of some kind
> + *
> + * Report details of a filesystem error to the super_operations::report_error
> + * callback if present; and to fsnotify for distribution to userspace. @sb,
> + * @gfp, @type, and @error must all be specified. For file I/O errors, the
> + * @inode, @pos, and @len fields must also be specified. For file metadata
> + * errors, @inode must be specified. If @inode is not NULL, then @inode->i_sb
> + * must point to @sb.
> + *
> + * Reporting work is deferred to a workqueue to ensure that ->report_error is
> + * called from process context without any locks held. An active reference to
> + * the inode is maintained until event handling is complete, and unmount will
> + * wait for queued events to drain.
> + *
> + * @sb: superblock of the filesystem
The normal convention is to have the arguments documented above the
long description. Any reason to deviate from that here?
^ permalink raw reply [flat|nested] 21+ messages in thread* Re: [PATCH 2/6] fs: report filesystem and file I/O errors to fsnotify
2025-12-18 5:21 ` Christoph Hellwig
@ 2025-12-18 18:44 ` Darrick J. Wong
2025-12-24 12:29 ` Christian Brauner
0 siblings, 1 reply; 21+ messages in thread
From: Darrick J. Wong @ 2025-12-18 18:44 UTC (permalink / raw)
To: Christoph Hellwig
Cc: brauner, linux-ext4, jack, linux-xfs, linux-fsdevel, gabriel,
amir73il
On Wed, Dec 17, 2025 at 09:21:52PM -0800, Christoph Hellwig wrote:
> > long s_min_writeback_pages;
> > +
> > + /* number of fserrors that are being sent to fsnotify/filesystems */
> > + refcount_t s_pending_errors;
>
> Use the same tab-alignment as the fields above? Also is this really
Will fix.
> a refcount? It's a counter, but not really a reference? I guess
> that doesn't matter too much.
<shrug> It does count pending events, but you could also look upon it as
a count of weak "references" to the super_block since the fserror_event
object does point to the super_block.
(Not sure what happens if we get more than 2^31 errors...)
> > +static inline void fserror_unmount(struct super_block *sb)
> > +{
> > + /*
> > + * If we don't drop the pending error count to zero, then wait for it
> > + * to drop below 1, which means that the pending errors cleared or
> > + * that we saturated the system with 1 billion+ concurrent events.
> > + */
> > + if (!refcount_dec_and_test(&sb->s_pending_errors))
> > + wait_var_event(&sb->s_pending_errors,
> > + refcount_read(&sb->s_pending_errors) < 1);
> > +}
>
> Should this be out of line?
Yes, it's better to hide these details (particularly since there's a fat
comment about the refcount bias) in fserror.c.
> > +/**
> > + * fserror_report - report a filesystem error of some kind
> > + *
> > + * Report details of a filesystem error to the super_operations::report_error
> > + * callback if present; and to fsnotify for distribution to userspace. @sb,
> > + * @gfp, @type, and @error must all be specified. For file I/O errors, the
> > + * @inode, @pos, and @len fields must also be specified. For file metadata
> > + * errors, @inode must be specified. If @inode is not NULL, then @inode->i_sb
> > + * must point to @sb.
> > + *
> > + * Reporting work is deferred to a workqueue to ensure that ->report_error is
> > + * called from process context without any locks held. An active reference to
> > + * the inode is maintained until event handling is complete, and unmount will
> > + * wait for queued events to drain.
> > + *
> > + * @sb: superblock of the filesystem
>
> The normal convention is to have the arguments documented above the
> long description. Any reason to deviate from that here?
Nope. Fixed.
--D
^ permalink raw reply [flat|nested] 21+ messages in thread* Re: [PATCH 2/6] fs: report filesystem and file I/O errors to fsnotify
2025-12-18 18:44 ` Darrick J. Wong
@ 2025-12-24 12:29 ` Christian Brauner
2026-01-06 16:42 ` Darrick J. Wong
0 siblings, 1 reply; 21+ messages in thread
From: Christian Brauner @ 2025-12-24 12:29 UTC (permalink / raw)
To: Darrick J. Wong
Cc: Christoph Hellwig, linux-ext4, jack, linux-xfs, linux-fsdevel,
gabriel, amir73il
> Nope. Fixed.
I've pulled this from the provided branch which already contains the
mentioned fixes. It now lives in vfs-7.0.fserror. As an aside, the
numbering for this patch series was very odd which tripped b4 so I
applied it with manual massaging. Let me know if there are any issues.
^ permalink raw reply [flat|nested] 21+ messages in thread
* Re: [PATCH 2/6] fs: report filesystem and file I/O errors to fsnotify
2025-12-24 12:29 ` Christian Brauner
@ 2026-01-06 16:42 ` Darrick J. Wong
2026-01-12 13:17 ` Christian Brauner
0 siblings, 1 reply; 21+ messages in thread
From: Darrick J. Wong @ 2026-01-06 16:42 UTC (permalink / raw)
To: Christian Brauner
Cc: Christoph Hellwig, linux-ext4, jack, linux-xfs, linux-fsdevel,
gabriel, amir73il
On Wed, Dec 24, 2025 at 01:29:21PM +0100, Christian Brauner wrote:
> > Nope. Fixed.
>
> I've pulled this from the provided branch which already contains the
> mentioned fixes. It now lives in vfs-7.0.fserror. As an aside, the
> numbering for this patch series was very odd which tripped b4 so I
> applied it with manual massaging. Let me know if there are any issues.
Thank you! But, uh... do you want me to fix the things that hch and jan
mentioned? Or have you already fixed them? I don't see a
vfs-7.0.fserror branch on the vfs tree[1]...
[1] https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git/refs/heads
--D
^ permalink raw reply [flat|nested] 21+ messages in thread
* Re: [PATCH 2/6] fs: report filesystem and file I/O errors to fsnotify
2026-01-06 16:42 ` Darrick J. Wong
@ 2026-01-12 13:17 ` Christian Brauner
2026-01-12 18:50 ` Darrick J. Wong
0 siblings, 1 reply; 21+ messages in thread
From: Christian Brauner @ 2026-01-12 13:17 UTC (permalink / raw)
To: Darrick J. Wong
Cc: Christoph Hellwig, linux-ext4, jack, linux-xfs, linux-fsdevel,
gabriel, amir73il
On Tue, Jan 06, 2026 at 08:42:30AM -0800, Darrick J. Wong wrote:
> On Wed, Dec 24, 2025 at 01:29:21PM +0100, Christian Brauner wrote:
> > > Nope. Fixed.
> >
> > I've pulled this from the provided branch which already contains the
> > mentioned fixes. It now lives in vfs-7.0.fserror. As an aside, the
> > numbering for this patch series was very odd which tripped b4 so I
> > applied it with manual massaging. Let me know if there are any issues.
>
> Thank you! But, uh... do you want me to fix the things that hch and jan
> mentioned? Or have you already fixed them? I don't see a
> vfs-7.0.fserror branch on the vfs tree[1]...
>
> [1] https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git/refs/heads
Before Christmas and the new year I didn't push anything out so we don't
end up in a situation where -next is broken but half the people are
still on vacation or are busy catching up.
I'm back now. Please just send a version with the fixes now.
^ permalink raw reply [flat|nested] 21+ messages in thread
* Re: [PATCH 2/6] fs: report filesystem and file I/O errors to fsnotify
2026-01-12 13:17 ` Christian Brauner
@ 2026-01-12 18:50 ` Darrick J. Wong
0 siblings, 0 replies; 21+ messages in thread
From: Darrick J. Wong @ 2026-01-12 18:50 UTC (permalink / raw)
To: Christian Brauner
Cc: Christoph Hellwig, linux-ext4, jack, linux-xfs, linux-fsdevel,
gabriel, amir73il
On Mon, Jan 12, 2026 at 02:17:14PM +0100, Christian Brauner wrote:
> On Tue, Jan 06, 2026 at 08:42:30AM -0800, Darrick J. Wong wrote:
> > On Wed, Dec 24, 2025 at 01:29:21PM +0100, Christian Brauner wrote:
> > > > Nope. Fixed.
> > >
> > > I've pulled this from the provided branch which already contains the
> > > mentioned fixes. It now lives in vfs-7.0.fserror. As an aside, the
> > > numbering for this patch series was very odd which tripped b4 so I
> > > applied it with manual massaging. Let me know if there are any issues.
> >
> > Thank you! But, uh... do you want me to fix the things that hch and jan
> > mentioned? Or have you already fixed them? I don't see a
> > vfs-7.0.fserror branch on the vfs tree[1]...
> >
> > [1] https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git/refs/heads
>
> Before Christmas and the new year I didn't push anything out so we don't
> end up in a situation where -next is broken but half the people are
> still on vacation or are busy catching up.
>
> I'm back now. Please just send a version with the fixes now.
Ok, thanks for the update. I'll send the latest version to -fsdevel.
--D
^ permalink raw reply [flat|nested] 21+ messages in thread
* Re: [PATCH 2/6] fs: report filesystem and file I/O errors to fsnotify
2025-12-18 2:03 ` [PATCH 2/6] fs: report filesystem and file I/O errors to fsnotify Darrick J. Wong
2025-12-18 5:21 ` Christoph Hellwig
@ 2025-12-22 15:36 ` Jan Kara
2026-01-06 17:35 ` Darrick J. Wong
1 sibling, 1 reply; 21+ messages in thread
From: Jan Kara @ 2025-12-22 15:36 UTC (permalink / raw)
To: Darrick J. Wong
Cc: brauner, hch, linux-ext4, jack, linux-xfs, linux-fsdevel, gabriel,
amir73il
On Wed 17-12-25 18:03:11, Darrick J. Wong wrote:
> From: Darrick J. Wong <djwong@kernel.org>
>
> Create some wrapper code around struct super_block so that filesystems
> have a standard way to queue filesystem metadata and file I/O error
> reports to have them sent to fsnotify.
>
> If a filesystem wants to provide an error number, it must supply only
> negative error numbers. These are stored internally as negative
> numbers, but they are converted to positive error numbers before being
> passed to fanotify, per the fanotify(7) manpage. Implementations of
> super_operations::report_error are passed the raw internal event data.
>
> Note that we have to play some shenanigans with mempools and queue_work
> so that the error handling doesn't happen outside of process context,
> and the event handler functions (both ->report_error and fsnotify) can
> handle file I/O error messages without having to worry about whatever
> locks might be held. This asynchronicity requires that unmount wait for
> pending events to clear.
>
> Add a new callback to the superblock operations structure so that
> filesystem drivers can themselves respond to file I/O errors if they so
> desire. This will be used for an upcoming self-healing patchset for
> XFS.
>
> Suggested-by: Christoph Hellwig <hch@lst.de>
> Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
Looks good to me. Besides the nits Christoph commented on just two comments:
> +static inline struct fserror_event *fserror_alloc_event(struct super_block *sb,
> + gfp_t gfp_flags)
> +{
> + struct fserror_event *event = NULL;
> +
> + /*
> + * If pending_errors already reached zero or is no longer active,
> + * the superblock is being deactivated so there's no point in
> + * continuing.
> + */
> + if (!refcount_inc_not_zero(&sb->s_pending_errors))
> + return NULL;
It would be good here or in the above comment explicitely mention that the
ordering of s_pending_errors check and SB_ACTIVE check is mandated by the
ordering in generic_shutdown_super() and that the barriers are implicitely
provided by the refcount manipulations here and in fserror_unmount().
> + if (!(sb->s_flags & SB_ACTIVE))
> + goto out_pending;
> +
> + event = mempool_alloc(&fserror_events_pool, gfp_flags);
> + if (!event)
> + goto out_pending;
> +
> + /* mempool_alloc doesn't support GFP_ZERO */
> + memset(event, 0, sizeof(*event));
> + event->sb = sb;
> + INIT_WORK(&event->work, fserror_worker);
> +
> + return event;
> +
> +out_pending:
> + fserror_pending_dec(sb);
> + return NULL;
> +}
> +
> +/**
> + * fserror_report - report a filesystem error of some kind
> + *
> + * Report details of a filesystem error to the super_operations::report_error
> + * callback if present; and to fsnotify for distribution to userspace. @sb,
> + * @gfp, @type, and @error must all be specified. For file I/O errors, the
> + * @inode, @pos, and @len fields must also be specified. For file metadata
> + * errors, @inode must be specified. If @inode is not NULL, then @inode->i_sb
> + * must point to @sb.
> + *
> + * Reporting work is deferred to a workqueue to ensure that ->report_error is
> + * called from process context without any locks held. An active reference to
> + * the inode is maintained until event handling is complete, and unmount will
> + * wait for queued events to drain.
> + *
> + * @sb: superblock of the filesystem
> + * @inode: inode within that filesystem, if applicable
> + * @type: type of error encountered
> + * @pos: start of inode range affected, if applicable
> + * @len: length of inode range affected, if applicable
> + * @error: error number encountered, must be negative
> + * @gfp: memory allocation flags for conveying the event to a worker,
> + * since this function can be called from atomic contexts
> + */
> +void fserror_report(struct super_block *sb, struct inode *inode,
> + enum fserror_type type, loff_t pos, u64 len, int error,
> + gfp_t gfp)
> +{
> + struct fserror_event *event;
> +
> + /* sb and inode must be from the same filesystem */
> + WARN_ON_ONCE(inode && inode->i_sb != sb);
> +
> + /* error number must be negative */
> + WARN_ON_ONCE(error >= 0);
Since the error reporting is kind of expensive now (allocation & queueing
work) it would be nice to check somebody actually cares about the error
events at all. We can provide a helper from fsnotify for that, I'm not sure
about ->report_error hook since it didn't get used in this series at all in
the end...
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
^ permalink raw reply [flat|nested] 21+ messages in thread* Re: [PATCH 2/6] fs: report filesystem and file I/O errors to fsnotify
2025-12-22 15:36 ` Jan Kara
@ 2026-01-06 17:35 ` Darrick J. Wong
0 siblings, 0 replies; 21+ messages in thread
From: Darrick J. Wong @ 2026-01-06 17:35 UTC (permalink / raw)
To: Jan Kara
Cc: brauner, hch, linux-ext4, linux-xfs, linux-fsdevel, gabriel,
amir73il
On Mon, Dec 22, 2025 at 04:36:14PM +0100, Jan Kara wrote:
> On Wed 17-12-25 18:03:11, Darrick J. Wong wrote:
> > From: Darrick J. Wong <djwong@kernel.org>
> >
> > Create some wrapper code around struct super_block so that filesystems
> > have a standard way to queue filesystem metadata and file I/O error
> > reports to have them sent to fsnotify.
> >
> > If a filesystem wants to provide an error number, it must supply only
> > negative error numbers. These are stored internally as negative
> > numbers, but they are converted to positive error numbers before being
> > passed to fanotify, per the fanotify(7) manpage. Implementations of
> > super_operations::report_error are passed the raw internal event data.
> >
> > Note that we have to play some shenanigans with mempools and queue_work
> > so that the error handling doesn't happen outside of process context,
> > and the event handler functions (both ->report_error and fsnotify) can
> > handle file I/O error messages without having to worry about whatever
> > locks might be held. This asynchronicity requires that unmount wait for
> > pending events to clear.
> >
> > Add a new callback to the superblock operations structure so that
> > filesystem drivers can themselves respond to file I/O errors if they so
> > desire. This will be used for an upcoming self-healing patchset for
> > XFS.
> >
> > Suggested-by: Christoph Hellwig <hch@lst.de>
> > Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
>
> Looks good to me. Besides the nits Christoph commented on just two comments:
>
> > +static inline struct fserror_event *fserror_alloc_event(struct super_block *sb,
> > + gfp_t gfp_flags)
> > +{
> > + struct fserror_event *event = NULL;
> > +
> > + /*
> > + * If pending_errors already reached zero or is no longer active,
> > + * the superblock is being deactivated so there's no point in
> > + * continuing.
> > + */
> > + if (!refcount_inc_not_zero(&sb->s_pending_errors))
> > + return NULL;
>
> It would be good here or in the above comment explicitely mention that the
> ordering of s_pending_errors check and SB_ACTIVE check is mandated by the
> ordering in generic_shutdown_super() and that the barriers are implicitely
> provided by the refcount manipulations here and in fserror_unmount().
Ok. I'll send a follow-on patch, though I don't see vfs-7.0.fserror on
vfs.git so I'm confused about where things are right now.
> > + if (!(sb->s_flags & SB_ACTIVE))
> > + goto out_pending;
> > +
> > + event = mempool_alloc(&fserror_events_pool, gfp_flags);
> > + if (!event)
> > + goto out_pending;
> > +
> > + /* mempool_alloc doesn't support GFP_ZERO */
> > + memset(event, 0, sizeof(*event));
> > + event->sb = sb;
> > + INIT_WORK(&event->work, fserror_worker);
> > +
> > + return event;
> > +
> > +out_pending:
> > + fserror_pending_dec(sb);
> > + return NULL;
> > +}
> > +
> > +/**
> > + * fserror_report - report a filesystem error of some kind
> > + *
> > + * Report details of a filesystem error to the super_operations::report_error
> > + * callback if present; and to fsnotify for distribution to userspace. @sb,
> > + * @gfp, @type, and @error must all be specified. For file I/O errors, the
> > + * @inode, @pos, and @len fields must also be specified. For file metadata
> > + * errors, @inode must be specified. If @inode is not NULL, then @inode->i_sb
> > + * must point to @sb.
> > + *
> > + * Reporting work is deferred to a workqueue to ensure that ->report_error is
> > + * called from process context without any locks held. An active reference to
> > + * the inode is maintained until event handling is complete, and unmount will
> > + * wait for queued events to drain.
> > + *
> > + * @sb: superblock of the filesystem
> > + * @inode: inode within that filesystem, if applicable
> > + * @type: type of error encountered
> > + * @pos: start of inode range affected, if applicable
> > + * @len: length of inode range affected, if applicable
> > + * @error: error number encountered, must be negative
> > + * @gfp: memory allocation flags for conveying the event to a worker,
> > + * since this function can be called from atomic contexts
> > + */
> > +void fserror_report(struct super_block *sb, struct inode *inode,
> > + enum fserror_type type, loff_t pos, u64 len, int error,
> > + gfp_t gfp)
> > +{
> > + struct fserror_event *event;
> > +
> > + /* sb and inode must be from the same filesystem */
> > + WARN_ON_ONCE(inode && inode->i_sb != sb);
> > +
> > + /* error number must be negative */
> > + WARN_ON_ONCE(error >= 0);
>
> Since the error reporting is kind of expensive now (allocation & queueing
> work) it would be nice to check somebody actually cares about the error
> events at all. We can provide a helper from fsnotify for that, I'm not sure
> about ->report_error hook since it didn't get used in this series at all in
> the end...
I didn't quite get to posting that patchset before vacation, but it's
posted now in "xfs: convey file I/O errors to the health monitor":
https://lore.kernel.org/linux-fsdevel/176766637421.774337.94510884010750487.stgit@frogsfrogsfrogs/T/#Z2e.:..:176766637421.774337.94510884010750487.stgit::40frogsfrogsfrogs:1fs:xfs:xfs_super.c
--D
>
> Honza
> --
> Jan Kara <jack@suse.com>
> SUSE Labs, CR
>
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