From: "Theodore Ts'o" <tytso@mit.edu>
To: Ext4 Developers List <linux-ext4@vger.kernel.org>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Subject: [PATCH] ext4: make dioread_nolock the default
Date: Fri, 24 Jan 2020 21:22:54 -0500 [thread overview]
Message-ID: <20200125022254.1101588-1-tytso@mit.edu> (raw)
This fixes the direct I/O versus writeback race which can reveal stale
data, and it improves the tail latency of commits on slow devices.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
fs/ext4/super.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index ecf36a23e0c4..c6fe742db798 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1592,6 +1592,7 @@ static const match_table_t tokens = {
{Opt_auto_da_alloc, "auto_da_alloc"},
{Opt_noauto_da_alloc, "noauto_da_alloc"},
{Opt_dioread_nolock, "dioread_nolock"},
+ {Opt_dioread_lock, "nodioread_nolock"},
{Opt_dioread_lock, "dioread_lock"},
{Opt_discard, "discard"},
{Opt_nodiscard, "nodiscard"},
@@ -3764,6 +3765,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
set_opt(sb, NO_UID32);
/* xattr user namespace & acls are now defaulted on */
set_opt(sb, XATTR_USER);
+ set_opt(sb, DIOREAD_NOLOCK);
#ifdef CONFIG_EXT4_FS_POSIX_ACL
set_opt(sb, POSIX_ACL);
#endif
@@ -3931,9 +3933,8 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
#endif
if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA) {
- printk_once(KERN_WARNING "EXT4-fs: Warning: mounting "
- "with data=journal disables delayed "
- "allocation and O_DIRECT support!\n");
+ printk_once(KERN_WARNING "EXT4-fs: Warning: mounting with data=journal disables delayed allocation, dioread_nolock, and O_DIRECT support!\n");
+ clear_opt(sb, DIOREAD_NOLOCK);
if (test_opt2(sb, EXPLICIT_DELALLOC)) {
ext4_msg(sb, KERN_ERR, "can't mount with "
"both data=journal and delalloc");
--
2.24.1
reply other threads:[~2020-01-25 2:23 UTC|newest]
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