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Message-Id: <20230824092619.1327976-16-yi.zhang@huaweicloud.com>
Date: Thu, 24 Aug 2023 17:26:18 +0800
From: Zhang Yi <yi.zhang@...weicloud.com>
To: linux-ext4@...r.kernel.org
Cc: tytso@....edu, adilger.kernel@...ger.ca, jack@...e.cz,
yi.zhang@...wei.com, yi.zhang@...weicloud.com,
chengzhihao1@...wei.com, yukuai3@...wei.com
Subject: [RFC PATCH 15/16] ext4: flush delalloc blocks if no free space
From: Zhang Yi <yi.zhang@...wei.com>
For delalloc, the reserved metadata blocks count is calculated in the
worst case, so the reservation could be larger than the real needs, that
could lead to return false positive -ENOSPC when claiming free space. So
start a worker to flush delalloc blocks in ext4_should_retry_alloc().
If the s_dirtyclusters_counter is not zero, there may have some delalloc
metadata blocks that could be freed.
Signed-off-by: Zhang Yi <yi.zhang@...wei.com>
---
fs/ext4/balloc.c | 47 +++++++++++++++++++++++++++++++++++++++++------
fs/ext4/ext4.h | 5 +++++
fs/ext4/super.c | 12 ++++++++++++
3 files changed, 58 insertions(+), 6 deletions(-)
diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index 79b20d6ae39e..e8acc21ef56d 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -667,6 +667,30 @@ int ext4_claim_free_clusters(struct ext4_sb_info *sbi,
return -ENOSPC;
}
+void ext4_writeback_da_blocks(struct work_struct *work)
+{
+ struct ext4_sb_info *sbi = container_of(work, struct ext4_sb_info,
+ s_da_flush_work);
+
+ try_to_writeback_inodes_sb(sbi->s_sb, WB_REASON_FS_FREE_SPACE);
+}
+
+/*
+ * Writeback delallocated blocks and try to free unused reserved extent
+ * blocks, return 0 if no delalloc blocks need to writeback, 1 otherwise.
+ */
+static int ext4_flush_da_blocks(struct ext4_sb_info *sbi)
+{
+ if (!percpu_counter_read_positive(&sbi->s_dirtyclusters_counter) &&
+ !percpu_counter_sum(&sbi->s_dirtyclusters_counter))
+ return 0;
+
+ if (!work_busy(&sbi->s_da_flush_work))
+ queue_work(sbi->s_da_flush_wq, &sbi->s_da_flush_work);
+ flush_work(&sbi->s_da_flush_work);
+ return 1;
+}
+
/**
* ext4_should_retry_alloc() - check if a block allocation should be retried
* @sb: superblock
@@ -681,15 +705,22 @@ int ext4_claim_free_clusters(struct ext4_sb_info *sbi,
int ext4_should_retry_alloc(struct super_block *sb, int *retries)
{
struct ext4_sb_info *sbi = EXT4_SB(sb);
-
- if (!sbi->s_journal)
- return 0;
+ int result = 0;
if (++(*retries) > 3) {
percpu_counter_inc(&sbi->s_sra_exceeded_retry_limit);
return 0;
}
+ /*
+ * Flush allocated delalloc blocks and try to free unused
+ * reserved extent blocks.
+ */
+ if (test_opt(sb, DELALLOC))
+ result += ext4_flush_da_blocks(sbi);
+
+ if (!sbi->s_journal)
+ goto out;
/*
* if there's no indication that blocks are about to be freed it's
* possible we just missed a transaction commit that did so
@@ -701,16 +732,20 @@ int ext4_should_retry_alloc(struct super_block *sb, int *retries)
flush_work(&sbi->s_discard_work);
atomic_dec(&sbi->s_retry_alloc_pending);
}
- return ext4_has_free_clusters(sbi, 1, 0);
+ result += ext4_has_free_clusters(sbi, 1, 0);
+ goto out;
}
/*
* it's possible we've just missed a transaction commit here,
* so ignore the returned status
*/
- ext4_debug("%s: retrying operation after ENOSPC\n", sb->s_id);
+ result += 1;
(void) jbd2_journal_force_commit_nested(sbi->s_journal);
- return 1;
+out:
+ if (result)
+ ext4_debug("%s: retrying operation after ENOSPC\n", sb->s_id);
+ return result;
}
/*
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 67b12f9ffc50..6f4259ea6751 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1627,6 +1627,10 @@ struct ext4_sb_info {
/* workqueue for reserved extent conversions (buffered io) */
struct workqueue_struct *rsv_conversion_wq;
+ /* workqueue for delalloc buffer IO flushing */
+ struct workqueue_struct *s_da_flush_wq;
+ struct work_struct s_da_flush_work;
+
/* timer for periodic error stats printing */
struct timer_list s_err_report;
@@ -2716,6 +2720,7 @@ extern int ext4_wait_block_bitmap(struct super_block *sb,
struct buffer_head *bh);
extern struct buffer_head *ext4_read_block_bitmap(struct super_block *sb,
ext4_group_t block_group);
+extern void ext4_writeback_da_blocks(struct work_struct *work);
extern unsigned ext4_free_clusters_after_init(struct super_block *sb,
ext4_group_t block_group,
struct ext4_group_desc *gdp);
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 7bc7c8c0ed71..6f50975ba42e 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1335,6 +1335,8 @@ static void ext4_put_super(struct super_block *sb)
flush_work(&sbi->s_sb_upd_work);
destroy_workqueue(sbi->rsv_conversion_wq);
+ flush_work(&sbi->s_da_flush_work);
+ destroy_workqueue(sbi->s_da_flush_wq);
ext4_release_orphan_info(sb);
if (sbi->s_journal) {
@@ -5491,6 +5493,14 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb)
goto failed_mount4;
}
+ INIT_WORK(&sbi->s_da_flush_work, ext4_writeback_da_blocks);
+ sbi->s_da_flush_wq = alloc_workqueue("ext4_delalloc_flush", WQ_UNBOUND, 1);
+ if (!sbi->s_da_flush_wq) {
+ printk(KERN_ERR "EXT4-fs: failed to create workqueue\n");
+ err = -ENOMEM;
+ goto failed_mount4;
+ }
+
/*
* The jbd2_journal_load will have done any necessary log recovery,
* so we can safely mount the rest of the filesystem now.
@@ -5660,6 +5670,8 @@ failed_mount9: __maybe_unused
sb->s_root = NULL;
failed_mount4:
ext4_msg(sb, KERN_ERR, "mount failed");
+ if (sbi->s_da_flush_wq)
+ destroy_workqueue(sbi->s_da_flush_wq);
if (EXT4_SB(sb)->rsv_conversion_wq)
destroy_workqueue(EXT4_SB(sb)->rsv_conversion_wq);
failed_mount_wq:
--
2.39.2
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