[PATCH v4 03/31] ntfs: add filesystem metadata error reporting helpers

[Baolin Liu]

From: Baolin Liu <liubaolin@xxxxxxxxxx>

Add file and volume helpers to report metadata errors through the generic
deferred fsnotify infrastructure while retaining the volume error bit.
Pass the caller's errno unchanged.

Move ntfs_inode_base() to inode.h and use it to identify the base file for
attribute and extent inodes. Fall back to a volume report for I_FREEING
or I_WILL_FREE, when retaining the inode for deferred reporting is unsafe.
When SB_ACTIVE is clear, record only the volume error state.

Signed-off-by: Baolin Liu <liubaolin@xxxxxxxxxx>
---
 fs/ntfs/inode.c  |  7 -------
 fs/ntfs/inode.h  |  8 ++++++++
 fs/ntfs/super.c  | 29 +++++++++++++++++++++++++++++
 fs/ntfs/volume.h |  3 +++
 4 files changed, 40 insertions(+), 7 deletions(-)

diff --git a/fs/ntfs/inode.c b/fs/ntfs/inode.c
index 52e22022b4e7..c8560dd47d44 100644
--- a/fs/ntfs/inode.c
+++ b/fs/ntfs/inode.c
@@ -3532,13 +3532,6 @@ void ntfs_destroy_ext_inode(struct ntfs_inode *ni)
 	kmem_cache_free(ntfs_inode_cache, ni);
 }
 
-static struct ntfs_inode *ntfs_inode_base(struct ntfs_inode *ni)
-{
-	if (ni->nr_extents == -1)
-		return ni->ext.base_ntfs_ino;
-	return ni;
-}
-
 static int ntfs_attr_position(__le32 type, struct ntfs_attr_search_ctx *ctx)
 {
 	int err;
diff --git a/fs/ntfs/inode.h b/fs/ntfs/inode.h
index cf447fb51725..952398753ed1 100644
--- a/fs/ntfs/inode.h
+++ b/fs/ntfs/inode.h
@@ -298,6 +298,14 @@ static inline bool ntfs_inode_is_named_stream(struct ntfs_inode *ni)
 	return NInoAttr(ni) && ni->type == AT_DATA && ni->name_len;
 }
 
+/* Extent and attached attribute inodes refer to their base MFT inode. */
+static inline struct ntfs_inode *ntfs_inode_base(struct ntfs_inode *ni)
+{
+	if (ni->nr_extents == -1)
+		return ni->ext.base_ntfs_ino;
+	return ni;
+}
+
 /* Return the base MFT inode for an attribute inode, or @ni itself. */
 static inline struct ntfs_inode *ntfs_base_inode(struct ntfs_inode *ni)
 {
diff --git a/fs/ntfs/super.c b/fs/ntfs/super.c
index 71f0aea46bf8..df09c277ee54 100644
--- a/fs/ntfs/super.c
+++ b/fs/ntfs/super.c
@@ -14,6 +14,7 @@
 #include <linux/sched/mm.h>
 #include <linux/fs_context.h>
 #include <linux/fs_parser.h>
+#include <linux/fserror.h>
 
 #include "sysctl.h"
 #include "logfile.h"
@@ -426,6 +427,34 @@ const struct option_t on_errors_arr[] = {
 	{ 0,			NULL }
 };
 
+/*
+ * Report confirmed metadata corruption as -EFSCORRUPTED, matching the errno
+ * returned to the caller. Preserve the errno of I/O and recovery failures
+ * so listeners can distinguish their causes.
+ */
+void ntfs_report_metadata_error(struct ntfs_volume *vol, int error)
+{
+	NVolSetErrors(vol);
+	if (vol->sb->s_flags & SB_ACTIVE)
+		fserror_report_metadata(vol->sb, error, GFP_ATOMIC);
+}
+
+void ntfs_report_file_metadata_error(struct inode *inode, int error)
+{
+	struct ntfs_inode *ni = NTFS_I(inode);
+
+	/* Attribute inodes share the file handle of their base inode. */
+	inode = VFS_I(ntfs_inode_base(ni));
+	/* Eviction cannot retain an inode reference for the deferred report. */
+	if (inode_state_read_once(inode) & (I_FREEING | I_WILL_FREE)) {
+		ntfs_report_metadata_error(NTFS_SB(inode->i_sb), error);
+		return;
+	}
+	NVolSetErrors(NTFS_SB(inode->i_sb));
+	if (inode->i_sb->s_flags & SB_ACTIVE)
+		fserror_report_file_metadata(inode, error, GFP_ATOMIC);
+}
+
 void ntfs_handle_error(struct super_block *sb)
 {
 	struct ntfs_volume *vol = NTFS_SB(sb);
diff --git a/fs/ntfs/volume.h b/fs/ntfs/volume.h
index ed5c0ccb9cd9..27f58beb4b2d 100644
--- a/fs/ntfs/volume.h
+++ b/fs/ntfs/volume.h
@@ -262,6 +262,9 @@ DEFINE_NVOL_BIT_OPS(SymlinkNative)
 DEFINE_NVOL_BIT_OPS(MftBootstrap)
 DEFINE_NVOL_BIT_OPS(StreamsWindows)
 
+void ntfs_report_metadata_error(struct ntfs_volume *vol, int error);
+void ntfs_report_file_metadata_error(struct inode *inode, int error);
+
 static inline void ntfs_inc_free_clusters(struct ntfs_volume *vol, s64 nr)
 {
 	if (!NVolFreeClusterKnown(vol))
-- 
2.51.0