ext4: using nofail preallocation in ext4_es_insert_extent()

[ Upstream commit 2a69c45 ] Similar to in ext4_es_insert_delayed_block(), we use preallocations that do not fail to avoid inconsistencies, but we do not care about es that are not must be kept, and we return 0 even if such es memory allocation fails. Suggested-by: Jan Kara <[email protected]> Signed-off-by: Baokun Li <[email protected]> Reviewed-by: Jan Kara <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Theodore Ts'o <[email protected]> Stable-dep-of: 8e387c8 ("ext4: make sure allocate pending entry not fail") Signed-off-by: Sasha Levin <[email protected]>
viraniac · Dec 8, 2023 · 5527898 · 5527898
1 parent 2ae2be6
commit 5527898
Showing 1 changed file with 26 additions and 12 deletions.
diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c
@@ -841,8 +841,11 @@ int ext4_es_insert_extent(struct inode *inode, ext4_lblk_t lblk,
 {
 	struct extent_status newes;
 	ext4_lblk_t end = lblk + len - 1;
-	int err = 0;
+	int err1 = 0;
+	int err2 = 0;
 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	struct extent_status *es1 = NULL;
+	struct extent_status *es2 = NULL;
 
 	if (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
 		return 0;
@@ -870,29 +873,40 @@ int ext4_es_insert_extent(struct inode *inode, ext4_lblk_t lblk,
 
 	ext4_es_insert_extent_check(inode, &newes);
 
+retry:
+	if (err1 && !es1)
+		es1 = __es_alloc_extent(true);
+	if ((err1 || err2) && !es2)
+		es2 = __es_alloc_extent(true);
 	write_lock(&EXT4_I(inode)->i_es_lock);
-	err = __es_remove_extent(inode, lblk, end, NULL, NULL);
-	if (err != 0)
+
+	err1 = __es_remove_extent(inode, lblk, end, NULL, es1);
+	if (err1 != 0)
+		goto error;
+
+	err2 = __es_insert_extent(inode, &newes, es2);
+	if (err2 == -ENOMEM && !ext4_es_must_keep(&newes))
+		err2 = 0;
+	if (err2 != 0)
 		goto error;
-retry:
-	err = __es_insert_extent(inode, &newes, NULL);
-	if (err == -ENOMEM && __es_shrink(EXT4_SB(inode->i_sb),
-					  128, EXT4_I(inode)))
-		goto retry;
-	if (err == -ENOMEM && !ext4_es_must_keep(&newes))
-		err = 0;
 
 	if (sbi->s_cluster_ratio > 1 && test_opt(inode->i_sb, DELALLOC) &&
 	    (status & EXTENT_STATUS_WRITTEN ||
 	     status & EXTENT_STATUS_UNWRITTEN))
 		__revise_pending(inode, lblk, len);
 
+	/* es is pre-allocated but not used, free it. */
+	if (es1 && !es1->es_len)
+		__es_free_extent(es1);
+	if (es2 && !es2->es_len)
+		__es_free_extent(es2);
 error:
 	write_unlock(&EXT4_I(inode)->i_es_lock);
+	if (err1 || err2)
+		goto retry;
 
 	ext4_es_print_tree(inode);
-
-	return err;
+	return 0;
 }
 
 /*