linux-ext4 - [PATCH -v3] ext4: add ext4_es_store_pblock

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Message-Id: <1392947996-7630-1-git-send-email-tytso@mit.edu>
Date:	Thu, 20 Feb 2014 20:59:56 -0500
From:	Theodore Ts'o <tytso@....edu>
To:	Ext4 Developers List <linux-ext4@...r.kernel.org>
Cc:	Theodore Ts'o <tytso@....edu>
Subject: [PATCH -v3] ext4: add ext4_es_store_pblock_status()

Avoid false positives by static code analysis tools such as sparse and
coverity caused by the fact that we set the physical block, and then
the status in the extent_status structure.  It is also more efficient
to set both of these values at once.

Addresses-Coverity-Id: #989077
Addresses-Coverity-Id: #989078
Addresses-Coverity-Id: #1080722

Signed-off-by: "Theodore Ts'o" <tytso@....edu>
---
 fs/ext4/extents_status.c | 14 ++++++--------
 fs/ext4/extents_status.h |  9 +++++++++
 2 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c
index 3981ff7..a900004 100644
--- a/fs/ext4/extents_status.c
+++ b/fs/ext4/extents_status.c
@@ -658,8 +658,7 @@ int ext4_es_insert_extent(struct inode *inode, ext4_lblk_t lblk,
 
 	newes.es_lblk = lblk;
 	newes.es_len = len;
-	ext4_es_store_pblock(&newes, pblk);
-	ext4_es_store_status(&newes, status);
+	ext4_es_store_pblock_status(&newes, pblk, status);
 	trace_ext4_es_insert_extent(inode, &newes);
 
 	ext4_es_insert_extent_check(inode, &newes);
@@ -699,8 +698,7 @@ void ext4_es_cache_extent(struct inode *inode, ext4_lblk_t lblk,
 
 	newes.es_lblk = lblk;
 	newes.es_len = len;
-	ext4_es_store_pblock(&newes, pblk);
-	ext4_es_store_status(&newes, status);
+	ext4_es_store_pblock_status(&newes, pblk, status);
 	trace_ext4_es_cache_extent(inode, &newes);
 
 	if (!len)
@@ -812,13 +810,13 @@ retry:
 
 			newes.es_lblk = end + 1;
 			newes.es_len = len2;
+			block = 0x7FDEADBEEF;
 			if (ext4_es_is_written(&orig_es) ||
-			    ext4_es_is_unwritten(&orig_es)) {
+			    ext4_es_is_unwritten(&orig_es))
 				block = ext4_es_pblock(&orig_es) +
 					orig_es.es_len - len2;
-				ext4_es_store_pblock(&newes, block);
-			}
-			ext4_es_store_status(&newes, ext4_es_status(&orig_es));
+			ext4_es_store_pblock_status(&newes, block,
+						    ext4_es_status(&orig_es));
 			err = __es_insert_extent(inode, &newes);
 			if (err) {
 				es->es_lblk = orig_es.es_lblk;
diff --git a/fs/ext4/extents_status.h b/fs/ext4/extents_status.h
index 167f4ab8..f1b62a4 100644
--- a/fs/ext4/extents_status.h
+++ b/fs/ext4/extents_status.h
@@ -129,6 +129,15 @@ static inline void ext4_es_store_status(struct extent_status *es,
 		       (es->es_pblk & ~ES_MASK));
 }
 
+static inline void ext4_es_store_pblock_status(struct extent_status *es,
+					       ext4_fsblk_t pb,
+					       unsigned int status)
+{
+	es->es_pblk = (((ext4_fsblk_t)
+			(status & EXTENT_STATUS_FLAGS) << ES_SHIFT) |
+		       (pb & ~ES_MASK));
+}
+
 extern void ext4_es_register_shrinker(struct ext4_sb_info *sbi);
 extern void ext4_es_unregister_shrinker(struct ext4_sb_info *sbi);
 extern void ext4_es_lru_add(struct inode *inode);
-- 
1.9.0

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