linux-kernel - Re: [PATCH 2/3 v2] f2fs: clear writeback when compression failed

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Date: Tue, 16 Apr 2024 16:49:03 +0000
From: Jaegeuk Kim <jaegeuk@...nel.org>
To: linux-kernel@...r.kernel.org, linux-f2fs-devel@...ts.sourceforge.net
Subject: Re: [PATCH 2/3 v2] f2fs: clear writeback when compression failed

Let's stop issuing compressed writes and clear their writeback flags.

Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
---

 Now, I don't see any kernel hang for 24hours.

 Change log from v1:
  - fix bugs

 fs/f2fs/compress.c | 40 ++++++++++++++++++++++++++++++++++++++--
 1 file changed, 38 insertions(+), 2 deletions(-)

diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
index d67c471ab5df..b12d3a49bfda 100644
--- a/fs/f2fs/compress.c
+++ b/fs/f2fs/compress.c
@@ -1031,6 +1031,31 @@ static void set_cluster_writeback(struct compress_ctx *cc)
 	}
 }
 
+static void cancel_cluster_writeback(struct compress_ctx *cc,
+			struct compress_io_ctx *cic, int submitted)
+{
+	int i;
+
+	/* Wait for submitted IOs. */
+	if (submitted > 1) {
+		f2fs_submit_merged_write(F2FS_I_SB(cc->inode), DATA);
+		while (atomic_read(&cic->pending_pages) !=
+					(cc->valid_nr_cpages - submitted + 1))
+			f2fs_io_schedule_timeout(DEFAULT_IO_TIMEOUT);
+	}
+
+	/* Cancel writeback and stay locked. */
+	for (i = 0; i < cc->cluster_size; i++) {
+		if (i < submitted) {
+			inode_inc_dirty_pages(cc->inode);
+			lock_page(cc->rpages[i]);
+		}
+		clear_page_private_gcing(cc->rpages[i]);
+		if (folio_test_writeback(page_folio(cc->rpages[i])))
+			end_page_writeback(cc->rpages[i]);
+	}
+}
+
 static void set_cluster_dirty(struct compress_ctx *cc)
 {
 	int i;
@@ -1232,7 +1257,6 @@ static int f2fs_write_compressed_pages(struct compress_ctx *cc,
 		.page = NULL,
 		.encrypted_page = NULL,
 		.compressed_page = NULL,
-		.submitted = 0,
 		.io_type = io_type,
 		.io_wbc = wbc,
 		.encrypted = fscrypt_inode_uses_fs_layer_crypto(cc->inode) ?
@@ -1358,7 +1382,16 @@ static int f2fs_write_compressed_pages(struct compress_ctx *cc,
 			fio.compressed_page = cc->cpages[i - 1];
 
 		cc->cpages[i - 1] = NULL;
+		fio.submitted = 0;
 		f2fs_outplace_write_data(&dn, &fio);
+		if (unlikely(!fio.submitted)) {
+			cancel_cluster_writeback(cc, cic, i);
+
+			/* To call fscrypt_finalize_bounce_page */
+			i = cc->valid_nr_cpages;
+			*submitted = 0;
+			goto out_destroy_crypt;
+		}
 		(*submitted)++;
 unlock_continue:
 		inode_dec_dirty_pages(cc->inode);
@@ -1392,8 +1425,11 @@ static int f2fs_write_compressed_pages(struct compress_ctx *cc,
 out_destroy_crypt:
 	page_array_free(cc->inode, cic->rpages, cc->cluster_size);
 
-	for (--i; i >= 0; i--)
+	for (--i; i >= 0; i--) {
+		if (!cc->cpages[i])
+			continue;
 		fscrypt_finalize_bounce_page(&cc->cpages[i]);
+	}
 out_put_cic:
 	kmem_cache_free(cic_entry_slab, cic);
 out_put_dnode:
-- 
2.44.0.683.g7961c838ac-goog