linux-ext4 - [RFC PATCH v2 4/9] ext4: add prefetching support for freespace trees

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Message-Id: <20200821015523.1698374-5-harshads@google.com>
Date:   Thu, 20 Aug 2020 18:55:18 -0700
From:   Harshad Shirwadkar <harshadshirwadkar@...il.com>
To:     linux-ext4@...r.kernel.org
Cc:     tytso@....edu, lyx1209@...il.com,
        Harshad Shirwadkar <harshadshirwadkar@...il.com>
Subject: [RFC PATCH v2 4/9] ext4: add prefetching support for freespace trees

From: Harshad Shirwadkar <harshadshirwadkar@...il.com>

This patch supports creation of freespace trees for prefetched block
bitmaps.

Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@...il.com>
---
 fs/ext4/mballoc.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 4b1c405543f0..168e9708257f 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -3137,6 +3137,9 @@ ext4_group_t ext4_mb_prefetch(struct super_block *sb, ext4_group_t group,
 void ext4_mb_prefetch_fini(struct super_block *sb, ext4_group_t group,
 			   unsigned int nr)
 {
+	struct ext4_buddy e4b;
+	int ret;
+
 	while (nr-- > 0) {
 		struct ext4_group_desc *gdp = ext4_get_group_desc(sb, group,
 								  NULL);
@@ -3151,8 +3154,15 @@ void ext4_mb_prefetch_fini(struct super_block *sb, ext4_group_t group,
 		    ext4_free_group_clusters(sb, gdp) > 0 &&
 		    !(ext4_has_group_desc_csum(sb) &&
 		      (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)))) {
-			if (ext4_mb_init_group(sb, group, GFP_NOFS))
+			if (ext4_mb_frsp_on(sb)) {
+				ret = ext4_mb_load_allocator(sb, group, &e4b,
+							     0);
+				if (ret)
+					break;
+				ext4_mb_unload_allocator(&e4b);
+			} else if (ext4_mb_init_group(sb, group, GFP_NOFS)) {
 				break;
+			}
 		}
 	}
 }
-- 
2.28.0.297.g1956fa8f8d-goog