On Thu, May 19, 2011 at 10:11:34AM +0800, Robin Dong wrote:
> After mkfs without journal:
>
> # mkfs.ext4 -O ^has_journal /dev/sda
> # mount -t ext4 /dev/sda /test
>
> the /proc/mounts will show:
> "/dev/sda /test ext4 rw,relatime,user_xattr,acl,barrier=1,data=writeback 0 0"
> which usually make users think the fs is using writeback-mode.
>
> Signed-off-by: Robin Dong <sanbai@xxxxxxxxxx>
It's actually better to simply always not set WRITEBACK_DATA() if we
are not journaling (either because of a noload mount option or because
the file systme doesn't have a journal).
- Ted
commit d0e5cab82ecbe5578d3d17b90ba3515918ea0b9f
Author: Theodore Ts'o <tytso@xxxxxxx>
Date: Sun May 22 16:10:01 2011 -0400
ext4: don't show mount options in /proc/mounts if there is no journal
After creating an ext4 file system without a journal:
# mke2fs -t ext4 -O ^has_journal /dev/sda
# mount -t ext4 /dev/sda /test
the /proc/mounts will show:
"/dev/sda /test ext4 rw,relatime,user_xattr,acl,barrier=1,data=writeback 0 0"
which can fool users into thinking that the fs is using writeback mode.
So don't set the writeback option when the journal has not been
enabled; we don't depend on the writeback option being set, since
ext4_should_writeback_data() in ext4_jbd2.h tests to see if the
journal is not present before returning true.
Reported-by: Robin Dong <sanbai@xxxxxxxxxx>
Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx>
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index ed5e80e..fdce4ee 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3485,7 +3485,6 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
goto failed_mount_wq;
} else {
clear_opt(sb, DATA_FLAGS);
- set_opt(sb, WRITEBACK_DATA);
sbi->s_journal = NULL;
needs_recovery = 0;
goto no_journal;
--
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