Received-SPF: pass (google.com: domain of linux-ext4-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Haotian Li <lihaotian9@huawei.com>
Subject: [PATCH] e2fsprogs: Try again to solve unreliable io case
To:     Ext4 Developers List <linux-ext4@vger.kernel.org>
CC:     "Theodore Y. Ts'o" <tytso@mit.edu>,
        "harshad shirwadkar," <harshadshirwadkar@gmail.com>,
        "liuzhiqiang (I)" <liuzhiqiang26@huawei.com>,
        linfeilong <linfeilong@huawei.com>
Message-ID: <d4fd737d-4280-1aee-32ae-36b303e6644d@huawei.com>
Date:   Tue, 20 Apr 2021 15:18:05 +0800
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101
 Thunderbird/78.1.0
MIME-Version: 1.0
Content-Type: text/plain; charset="gbk"
Content-Transfer-Encoding: 7bit
Precedence: bulk

If some I/O error occured during e2fsck, for example the
fibre channel connections are flasky, the e2fsck may exit.
Try again in these I/O error cases may help e2fsck
successfully execute and fix the disk correctly.

We may try five times when io_channel_write/read failed.
Enable this option by setting true on unreliable_io in
configure file "e2fsck.conf".

Signed-off-by: Haotian Li <lihaotian9@huawei.com>
Signed-off-by: Zhiqiang Liu <liuzhiqiang26@huawei.com>
---
 e2fsck/unix.c           |   7 +++
 lib/ext2fs/ext2_io.h    |   3 ++
 lib/ext2fs/ext2fs.h     |   2 +-
 lib/ext2fs/io_manager.c | 102 ++++++++++++++++++++++++++++++----------
 lib/ext2fs/openfs.c     |   2 +
 lib/ext2fs/unix_io.c    |   4 ++
 6 files changed, 93 insertions(+), 27 deletions(-)

diff --git a/e2fsck/unix.c b/e2fsck/unix.c
index c5f9e441..faa2f77d 100644
--- a/e2fsck/unix.c
+++ b/e2fsck/unix.c
@@ -1398,6 +1398,7 @@ int main (int argc, char *argv[])
 	int journal_size;
 	int sysval, sys_page_size = 4096;
 	int old_bitmaps;
+	int unreliable_io;
 	__u32 features[3];
 	char *cp;
 	enum quota_type qtype;
@@ -1496,6 +1497,12 @@ restart:
 			    &old_bitmaps);
 	if (!old_bitmaps)
 		flags |= EXT2_FLAG_64BITS;
+
+	profile_get_boolean(ctx->profile, "options", "unreliable_io", 0, 0,
+			    &unreliable_io);
+	if (unreliable_io)
+		flags |= EXT2_FLAG_UNRELIABLE_IO;
+
 	if ((ctx->options & E2F_OPT_READONLY) == 0) {
 		flags |= EXT2_FLAG_RW;
 		if (!(ctx->mount_flags & EXT2_MF_ISROOT &&
diff --git a/lib/ext2fs/ext2_io.h b/lib/ext2fs/ext2_io.h
index 8fe5b323..38d23a1b 100644
--- a/lib/ext2fs/ext2_io.h
+++ b/lib/ext2fs/ext2_io.h
@@ -34,8 +34,10 @@ typedef struct struct_io_stats *io_stats;
 #define CHANNEL_FLAGS_DISCARD_ZEROES	0x02
 #define CHANNEL_FLAGS_BLOCK_DEVICE	0x04
 #define CHANNEL_FLAGS_THREADS		0x08
+#define CHANNEL_FLAGS_UNRELIABLE_IO     0x10

 #define io_channel_discard_zeroes_data(i) (i->flags & CHANNEL_FLAGS_DISCARD_ZEROES)
+#define UNRELIABLE_IO_RETRY_TIMES 5

 struct struct_io_channel {
 	errcode_t	magic;
@@ -107,6 +109,7 @@ struct struct_io_manager {
 #define IO_FLAG_FORCE_BOUNCE	0x0008
 #define IO_FLAG_THREADS		0x0010
 #define IO_FLAG_NOCACHE		0x0020
+#define IO_FLAG_UNRELIABLE_IO   0x0040

 /*
  * Convenience functions....
diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
index df150f00..4ce5e311 100644
--- a/lib/ext2fs/ext2fs.h
+++ b/lib/ext2fs/ext2fs.h
@@ -207,7 +207,7 @@ typedef struct ext2_file *ext2_file_t;
 #define EXT2_FLAG_BBITMAP_TAIL_PROBLEM	0x1000000
 #define EXT2_FLAG_IBITMAP_TAIL_PROBLEM	0x2000000
 #define EXT2_FLAG_THREADS		0x4000000
-
+#define EXT2_FLAG_UNRELIABLE_IO         0x8000000
 /*
  * Special flag in the ext2 inode i_flag field that means that this is
  * a new inode.  (So that ext2_write_inode() can clear extra fields.)
diff --git a/lib/ext2fs/io_manager.c b/lib/ext2fs/io_manager.c
index 996c31a1..f062ef0a 100644
--- a/lib/ext2fs/io_manager.c
+++ b/lib/ext2fs/io_manager.c
@@ -61,66 +61,116 @@ errcode_t io_channel_write_byte(io_channel channel, unsigned long offset,
 				int count, const void *data)
 {
 	EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
-
-	if (channel->manager->write_byte)
-		return channel->manager->write_byte(channel, offset,
+	errcode_t ret = EXT2_ET_UNIMPLEMENTED;
+       int retry_times = (channel->flags & CHANNEL_FLAGS_UNRELIABLE_IO) ?
+               UNRELIABLE_IO_RETRY_TIMES : 0;
+retry:
+	if (channel->manager->write_byte) {
+		ret = channel->manager->write_byte(channel, offset,
 						    count, data);
-
-	return EXT2_ET_UNIMPLEMENTED;
+		if (ret && retry_times) {
+                        retry_times--;
+                        goto retry;
+               }
+	}
+	return ret;
 }

 errcode_t io_channel_read_blk64(io_channel channel, unsigned long long block,
 				 int count, void *data)
 {
-	EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
-
-	if (channel->manager->read_blk64)
-		return (channel->manager->read_blk64)(channel, block,
+       EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+	errcode_t ret = 0;
+	int retry_times = (channel->flags & CHANNEL_FLAGS_UNRELIABLE_IO) ?
+		UNRELIABLE_IO_RETRY_TIMES : 0;
+retry_read_blk64:
+	if (channel->manager->read_blk64) {
+		ret = (channel->manager->read_blk64)(channel, block,
 						      count, data);
+		if (ret && retry_times) {
+			retry_times--;
+			goto retry_read_blk64;
+		}
+		return ret;
+	}

 	if ((block >> 32) != 0)
 		return EXT2_ET_IO_CHANNEL_NO_SUPPORT_64;
-
-	return (channel->manager->read_blk)(channel, (unsigned long) block,
+retry_read_blk:
+	ret = (channel->manager->read_blk)(channel, (unsigned long) block,
 					     count, data);
+	if (ret && retry_times) {
+		retry_times--;
+               goto retry_read_blk;
+       }
+	return ret;
 }

+
 errcode_t io_channel_write_blk64(io_channel channel, unsigned long long block,
 				 int count, const void *data)
 {
 	EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
-
-	if (channel->manager->write_blk64)
-		return (channel->manager->write_blk64)(channel, block,
+	errcode_t ret = 0;
+       int retry_times = (channel->flags & CHANNEL_FLAGS_UNRELIABLE_IO) ?
+                UNRELIABLE_IO_RETRY_TIMES : 0;
+retry_write_blk64:
+	if (channel->manager->write_blk64) {
+		ret = (channel->manager->write_blk64)(channel, block,
 						       count, data);
+		if (ret && retry_times) {
+                        retry_times--;
+                        goto retry_write_blk64;
+               }
+               return ret;
+        }

 	if ((block >> 32) != 0)
 		return EXT2_ET_IO_CHANNEL_NO_SUPPORT_64;
-
-	return (channel->manager->write_blk)(channel, (unsigned long) block,
+retry_write_blk:
+	ret = (channel->manager->write_blk)(channel, (unsigned long) block,
 					     count, data);
+	if (ret && retry_times) {
+               retry_times--;
+               goto retry_write_blk;
+       }
+	return ret;
 }

 errcode_t io_channel_discard(io_channel channel, unsigned long long block,
 			     unsigned long long count)
 {
 	EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
-
-	if (channel->manager->discard)
-		return (channel->manager->discard)(channel, block, count);
-
-	return EXT2_ET_UNIMPLEMENTED;
+	errcode_t ret = EXT2_ET_UNIMPLEMENTED;
+	int retry_times = (channel->flags & CHANNEL_FLAGS_UNRELIABLE_IO) ?
+	                UNRELIABLE_IO_RETRY_TIMES : 0;
+retry:
+	if (channel->manager->discard) {
+		ret = (channel->manager->discard)(channel, block, count);
+		if (ret && retry_times) {
+                       retry_times--;
+                       goto retry;
+               }
+	}
+	return ret;
 }

 errcode_t io_channel_zeroout(io_channel channel, unsigned long long block,
 			     unsigned long long count)
 {
 	EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
-
-	if (channel->manager->zeroout)
-		return (channel->manager->zeroout)(channel, block, count);
-
-	return EXT2_ET_UNIMPLEMENTED;
+	errcode_t ret = EXT2_ET_UNIMPLEMENTED;
+       int retry_times = (channel->flags & CHANNEL_FLAGS_UNRELIABLE_IO) ?
+                        UNRELIABLE_IO_RETRY_TIMES : 0;
+retry:
+	if (channel->manager->zeroout) {
+		ret = (channel->manager->zeroout)(channel, block, count);
+		if (ret && retry_times) {
+                        retry_times--;
+                        goto retry;
+               }
+       }
+	return ret;
 }

 errcode_t io_channel_alloc_buf(io_channel io, int count, void *ptr)
diff --git a/lib/ext2fs/openfs.c b/lib/ext2fs/openfs.c
index 5ec8ed5c..a98a5815 100644
--- a/lib/ext2fs/openfs.c
+++ b/lib/ext2fs/openfs.c
@@ -172,6 +172,8 @@ errcode_t ext2fs_open2(const char *name, const char *io_options,
 		io_flags |= IO_FLAG_DIRECT_IO;
 	if (flags & EXT2_FLAG_THREADS)
 		io_flags |= IO_FLAG_THREADS;
+	if (flags & EXT2_FLAG_UNRELIABLE_IO)
+		io_flags |= IO_FLAG_UNRELIABLE_IO;
 	retval = manager->open(fs->device_name, io_flags, &fs->io);
 	if (retval)
 		goto cleanup;
diff --git a/lib/ext2fs/unix_io.c b/lib/ext2fs/unix_io.c
index 64eee342..845a1e16 100644
--- a/lib/ext2fs/unix_io.c
+++ b/lib/ext2fs/unix_io.c
@@ -837,6 +837,10 @@ static errcode_t unix_open_channel(const char *name, int fd,
 		}
 	}
 #endif
+	if (flags & IO_FLAG_UNRELIABLE_IO) {
+		io->flags |= CHANNEL_FLAGS_UNRELIABLE_IO;
+	}
+
 	*channel = io;
 	return 0;

-- 
2.23.0