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From: David Howells <dhowells@redhat.com>
To: viro@zeniv.linux.org.uk
Cc: Jeff Layton <jlayton@kernel.org>,
	dhowells@redhat.com, torvalds@linux-foundation.org,
	raven@themaw.net, mszeredi@redhat.com, christian@brauner.io,
	jannh@google.com, darrick.wong@oracle.com, kzak@redhat.com,
	jlayton@redhat.com, linux-api@vger.kernel.org,
	linux-fsdevel@vger.kernel.org,
	linux-security-module@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH 17/18] vfs: allow fsinfo to fetch the current state of s_wb_err [ver #21]
Date: Mon, 03 Aug 2020 14:38:54 +0100	[thread overview]
Message-ID: <159646193490.1784947.15753060107959291101.stgit@warthog.procyon.org.uk> (raw)
In-Reply-To: <159646178122.1784947.11705396571718464082.stgit@warthog.procyon.org.uk>

From: Jeff Layton <jlayton@kernel.org>

Add a new "error_state" struct to fsinfo, and teach the kernel to fill
that out from sb->s_wb_err. There are two fields:

wb_error_last: the most recently recorded errno for the filesystem

wb_error_cookie: this value will change vs. the previously fetched
                 value if a new error was recorded since it was last
		 checked. Callers should treat this as an opaque value
		 that can be compared to earlier fetched values.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: David Howells <dhowells@redhat.com>
---

 fs/fsinfo.c                 |   11 +++++++++++
 include/uapi/linux/fsinfo.h |   13 +++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/fs/fsinfo.c b/fs/fsinfo.c
index f230124ffdf5..ea9d9821d76b 100644
--- a/fs/fsinfo.c
+++ b/fs/fsinfo.c
@@ -274,6 +274,16 @@ static int fsinfo_generic_seq_read(struct path *path, struct fsinfo_context *ctx
 	return m.count + 1;
 }
 
+static int fsinfo_generic_error_state(struct path *path,
+				      struct fsinfo_context *ctx)
+{
+	struct fsinfo_error_state *es = ctx->buffer;
+
+	es->wb_error_cookie = errseq_scrape(&path->dentry->d_sb->s_wb_err);
+	es->wb_error_last = es->wb_error_cookie & MAX_ERRNO;
+	return sizeof(*es);
+}
+
 static const struct fsinfo_attribute fsinfo_common_attributes[] = {
 	FSINFO_VSTRUCT	(FSINFO_ATTR_STATFS,		fsinfo_generic_statfs),
 	FSINFO_VSTRUCT	(FSINFO_ATTR_IDS,		fsinfo_generic_ids),
@@ -286,6 +296,7 @@ static const struct fsinfo_attribute fsinfo_common_attributes[] = {
 	FSINFO_STRING	(FSINFO_ATTR_SOURCE,		fsinfo_generic_mount_source),
 	FSINFO_STRING	(FSINFO_ATTR_CONFIGURATION,	fsinfo_generic_seq_read),
 	FSINFO_STRING	(FSINFO_ATTR_FS_STATISTICS,	fsinfo_generic_seq_read),
+	FSINFO_VSTRUCT	(FSINFO_ATTR_ERROR_STATE,	fsinfo_generic_error_state),
 
 	FSINFO_LIST	(FSINFO_ATTR_FSINFO_ATTRIBUTES,	(void *)123UL),
 	FSINFO_VSTRUCT_N(FSINFO_ATTR_FSINFO_ATTRIBUTE_INFO, (void *)123UL),
diff --git a/include/uapi/linux/fsinfo.h b/include/uapi/linux/fsinfo.h
index e40192d98648..dcd764771a7d 100644
--- a/include/uapi/linux/fsinfo.h
+++ b/include/uapi/linux/fsinfo.h
@@ -27,6 +27,7 @@
 #define FSINFO_ATTR_SOURCE		0x09	/* Superblock source/device name (string) */
 #define FSINFO_ATTR_CONFIGURATION	0x0a	/* Superblock configuration/options (string) */
 #define FSINFO_ATTR_FS_STATISTICS	0x0b	/* Superblock filesystem statistics (string) */
+#define FSINFO_ATTR_ERROR_STATE		0x0c	/* Superblock writeback error state */
 
 #define FSINFO_ATTR_FSINFO_ATTRIBUTE_INFO 0x100	/* Information about attr N (for path) */
 #define FSINFO_ATTR_FSINFO_ATTRIBUTES	0x101	/* List of supported attrs (for path) */
@@ -328,4 +329,16 @@ struct fsinfo_afs_server_address {
 
 #define FSINFO_ATTR_AFS_SERVER_ADDRESSES__STRUCT struct fsinfo_afs_server_address
 
+/*
+ * Information struct for fsinfo(FSINFO_ATTR_ERROR_STATE).
+ *
+ * Retrieve the error state for a filesystem.
+ */
+struct fsinfo_error_state {
+	__u32		wb_error_cookie;	/* writeback error cookie */
+	__u32		wb_error_last;		/* latest writeback error */
+};
+
+#define FSINFO_ATTR_ERROR_STATE__STRUCT struct fsinfo_error_state
+
 #endif /* _UAPI_LINUX_FSINFO_H */



  parent reply	other threads:[~2020-08-03 13:39 UTC|newest]

Thread overview: 49+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-03 13:36 [PATCH 00/18] VFS: Filesystem information " David Howells
2020-08-03 13:36 ` [PATCH 01/18] fsinfo: Introduce a non-repeating system-unique superblock ID " David Howells
2020-08-04  9:34   ` Miklos Szeredi
2020-08-03 13:36 ` [PATCH 02/18] fsinfo: Add fsinfo() syscall to query filesystem information " David Howells
2020-08-04 10:16   ` Miklos Szeredi
2020-08-04 11:34   ` David Howells
2020-08-27 11:27   ` Michael Kerrisk (man-pages)
2020-08-03 13:36 ` [PATCH 03/18] fsinfo: Provide a bitmap of the features a filesystem supports " David Howells
2020-08-03 13:37 ` [PATCH 04/18] fsinfo: Allow retrieval of superblock devname, options and stats " David Howells
2020-08-03 13:37 ` [PATCH 05/18] fsinfo: Allow fsinfo() to look up a mount object by ID " David Howells
2020-08-04 10:33   ` Miklos Szeredi
2020-08-03 13:37 ` [PATCH 06/18] fsinfo: Add a uniquifier ID to struct mount " David Howells
2020-08-04 10:41   ` Miklos Szeredi
2020-08-04 12:32     ` Ian Kent
2020-08-05 14:13   ` David Howells
2020-08-05 14:46     ` Miklos Szeredi
2020-08-05 15:30     ` David Howells
2020-08-05 19:33       ` Matthew Wilcox
2020-08-06  5:43         ` Ian Kent
2020-08-03 13:37 ` [PATCH 07/18] fsinfo: Allow mount information to be queried " David Howells
2020-08-03 13:37 ` [PATCH 08/18] fsinfo: Allow mount topology and propagation info to be retrieved " David Howells
2020-08-04 13:38   ` Miklos Szeredi
2020-08-05 15:37   ` David Howells
2020-08-05 17:19     ` Miklos Szeredi
2020-08-03 13:37 ` [PATCH 09/18] watch_queue: Mount event counters " David Howells
2020-08-03 13:37 ` [PATCH 10/18] fsinfo: Provide notification overrun handling support " David Howells
2020-08-04 13:56   ` Miklos Szeredi
2020-08-05  2:05     ` Ian Kent
2020-08-05  2:46       ` Ian Kent
2020-08-05  7:45         ` Miklos Szeredi
2020-08-05 11:23           ` Ian Kent
2020-08-05 11:27             ` Miklos Szeredi
2020-08-06  1:47               ` Ian Kent
2020-08-05 16:06   ` David Howells
2020-08-05 17:26     ` Miklos Szeredi
2020-08-03 13:37 ` [PATCH 11/18] fsinfo: sample: Mount listing program " David Howells
2020-08-03 13:38 ` [PATCH 12/18] fsinfo: Add API documentation " David Howells
2020-08-03 13:38 ` [PATCH 13/18] fsinfo: Add support for AFS " David Howells
2020-08-03 13:38 ` [PATCH 14/18] fsinfo: Add support to ext4 " David Howells
2020-08-03 13:38 ` [PATCH 15/18] fsinfo: Add an attribute that lists all the visible mounts in a namespace " David Howells
2020-08-04 14:05   ` Miklos Szeredi
2020-08-05  0:59     ` Ian Kent
2020-08-05 16:44   ` David Howells
2020-08-03 13:38 ` [PATCH 16/18] errseq: add a new errseq_scrape function " David Howells
2020-08-03 13:38 ` David Howells [this message]
2020-08-03 13:39 ` [PATCH 18/18] samples: add error state information to test-fsinfo.c " David Howells
2020-08-04 15:39 ` [PATCH 00/18] VFS: Filesystem information " James Bottomley
2020-08-04 19:18   ` Miklos Szeredi
2020-08-05 17:13 ` David Howells

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