libext2fs: don't old the CACHE_MTX while doing I/O

Signed-off-by: zhanchengbin <zhanchengbin1@huawei.com>

0011-libext2fs-don-t-old-the-CACHE_MTX-while-doing-I-O.patch

@@ -0,0 +1,106 @@
+From 699d448eee4b991acafaae4e4f8222be332d6837 Mon Sep 17 00:00:00 2001
+From: Theodore Ts'o <tytso@mit.edu>
+Date: Thu, 9 Dec 2021 10:55:54 -0500
+Subject: [PATCH] libext2fs: don't old the CACHE_MTX while doing I/O
+
+A report a deadlock problem caused by I/O errors (caused by e2fsck's
+error handler trying to write to a bad block to perform a forced
+rewrite) uncovered that we were holding the CACHE_MTX while doing read
+operations.  This serialized read operations which destroyed the
+performance benefits from doing parallel bitmap loading (or the
+parallel e2fsck processing under development).
+
+So restructure the code in unix_read_blk64() so that the read is
+always done into the user-provided buffer, and then copied into the
+cache afterwards.
+
+Signed-off-by: Theodore Ts'o <tytso@mit.edu>
+---
+ lib/ext2fs/unix_io.c | 38 +++++++++++++-------------------------
+ 1 file changed, 13 insertions(+), 25 deletions(-)
+
+diff --git a/lib/ext2fs/unix_io.c b/lib/ext2fs/unix_io.c
+index 50ac737..e53db33 100644
+--- a/lib/ext2fs/unix_io.c
++++ b/lib/ext2fs/unix_io.c
+@@ -977,8 +977,8 @@ static errcode_t unix_read_blk64(io_channel channel, unsigned long long block,
+ 			       int count, void *buf)
+ {
+ 	struct unix_private_data *data;
+-	struct unix_cache *cache, *reuse[READ_DIRECT_SIZE];
+-	errcode_t	retval = 0;
++	struct unix_cache *cache;
++	errcode_t	retval;
+ 	char		*cp;
+ 	int		i, j;
+ 
+@@ -1005,7 +1005,7 @@ static errcode_t unix_read_blk64(io_channel channel, unsigned long long block,
+ 	mutex_lock(data, CACHE_MTX);
+ 	while (count > 0) {
+ 		/* If it's in the cache, use it! */
+-		if ((cache = find_cached_block(data, block, &reuse[0]))) {
++		if ((cache = find_cached_block(data, block, NULL))) {
+ #ifdef DEBUG
+ 			printf("Using cached block %lu\n", block);
+ #endif
+@@ -1015,47 +1015,35 @@ static errcode_t unix_read_blk64(io_channel channel, unsigned long long block,
+ 			cp += channel->block_size;
+ 			continue;
+ 		}
+-		if (count == 1) {
+-			/*
+-			 * Special case where we read directly into the
+-			 * cache buffer; important in the O_DIRECT case
+-			 */
+-			cache = reuse[0];
+-			reuse_cache(channel, data, cache, block);
+-			if ((retval = raw_read_blk(channel, data, block, 1,
+-						   cache->buf))) {
+-				cache->in_use = 0;
+-				break;
+-			}
+-			memcpy(cp, cache->buf, channel->block_size);
+-			retval = 0;
+-			break;
+-		}
+ 
+ 		/*
+ 		 * Find the number of uncached blocks so we can do a
+ 		 * single read request
+ 		 */
+ 		for (i=1; i < count; i++)
+-			if (find_cached_block(data, block+i, &reuse[i]))
++			if (find_cached_block(data, block+i, NULL))
+ 				break;
+ #ifdef DEBUG
+ 		printf("Reading %d blocks starting at %lu\n", i, block);
+ #endif
++		mutex_unlock(data, CACHE_MTX);
+ 		if ((retval = raw_read_blk(channel, data, block, i, cp)))
+-			break;
++			return retval;
++		mutex_lock(data, CACHE_MTX);
+ 
+ 		/* Save the results in the cache */
+ 		for (j=0; j < i; j++) {
++			if (!find_cached_block(data, block, &cache)) {
++				reuse_cache(channel, data, cache, block);
++				memcpy(cache->buf, cp, channel->block_size);
++			}
+ 			count--;
+-			cache = reuse[j];
+-			reuse_cache(channel, data, cache, block++);
+-			memcpy(cache->buf, cp, channel->block_size);
++			block++;
+ 			cp += channel->block_size;
+ 		}
+ 	}
+ 	mutex_unlock(data, CACHE_MTX);
+-	return retval;
++	return 0;
+ #endif /* NO_IO_CACHE */
+ }
+ 
+-- 
+1.8.3.1
+

e2fsprogs.spec

@@ -1,6 +1,6 @@
 Name:           e2fsprogs
 Version:        1.46.4
-Release:        5
+Release:        6
 Summary:        Second extended file system management tools
 License:        GPLv2+ and LGPLv2 and MIT
 URL:            http://e2fsprogs.sourceforge.net/
@@ -16,6 +16,7 @@ Patch7:		0007-e2fsck-exit-journal-recovery-when-jounral-superblock.patch
 Patch8:		0008-e2fsck-add-env-param-E2FS_UNRELIABLE_IO-to-fi.patch
 Patch9:		0009-e2mmpstatus.8.in-detele-filesystem-can-be-UUID-or-LA.patch		
 Patch10:	0010-tests-update-expect-file-for-u_direct_io.patch
+Patch11:	0011-libext2fs-don-t-old-the-CACHE_MTX-while-doing-I-O.patch
 
 
 BuildRequires:  gcc pkgconfig texinfo
@@ -138,6 +139,9 @@ exit 0
 %{_mandir}/man8/*
 
 %changelog
+* Wed Feb 9 2022 zhanchengbin <zhanchengbin1@huawei.com> - 1.46.4-6
+- libext2fs: don't old the CACHE_MTX while doing I/O
+
 * Thu Feb 8 2022 zhanchengbin <zhanchengbin1@huawei.com> - 1.46.4-5
 - tests: update expect file for u_direct_io