From: Theodore Ts'o <tytso@xxxxxxx> [ Upstream commit 244adf6426ee31a83f397b700d964cff12a247d3 ] 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. Link: https://lore.kernel.org/r/20200125022254.1101588-1-tytso@xxxxxxx Signed-off-by: Theodore Ts'o <tytso@xxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- 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 0c15ff19acbd4..0076ea7427e34 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -1538,6 +1538,7 @@ 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"}, @@ -3712,6 +3713,7 @@ 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 @@ -3849,9 +3851,8 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) goto failed_mount; 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"); -- 2.25.1
