2009-09-16 15:21:12

by Theodore Ts'o

Subject: [PATCH] ext3: Don't update superblock write time when filesystem is read-only

This avoids updating the superblock write time when we are mounting
the root file system read/only but we need to replay the journal; at
that point, for people who are east of GMT and who make their clock
tick in localtime for Windows bug-for-bug compatibility, and this will
cause e2fsck to complain and force a full file system check.

Signed-off-by: "Theodore Ts'o" <[email protected]>
---
fs/ext3/super.c | 13 ++++++++++++-
1 files changed, 12 insertions(+), 1 deletions(-)

diff --git a/fs/ext3/super.c b/fs/ext3/super.c
index a8d80a7..62c86af 100644
--- a/fs/ext3/super.c
+++ b/fs/ext3/super.c
@@ -2321,7 +2321,18 @@ static int ext3_commit_super(struct super_block *sb,

if (!sbh)
return error;
- es->s_wtime = cpu_to_le32(get_seconds());
+ /*
+ * If the file system is mounted read-only, don't update the
+ * superblock write time. This avoids updating the superblock
+ * write time when we are mounting the root file system
+ * read/only but we need to replay the journal; at that point,
+ * for people who are east of GMT and who make their clock
+ * tick in localtime for Windows bug-for-bug compatibility,
+ * the clock is set in the future, and this will cause e2fsck
+ * to complain and force a full file system check.
+ */
+ if (!(sb->s_flags & MS_RDONLY))
+ es->s_wtime = cpu_to_le32(get_seconds());
es->s_free_blocks_count = cpu_to_le32(ext3_count_free_blocks(sb));
es->s_free_inodes_count = cpu_to_le32(ext3_count_free_inodes(sb));
BUFFER_TRACE(sbh, "marking dirty");
--
1.6.3.2.1.gb9f7d.dirty

2009-09-16 17:27:15

by Jan Kara

Subject: Re: [PATCH] ext3: Don't update superblock write time when filesystem is read-only

On Wed 16-09-09 11:21:13, Theodore Ts'o wrote:
> This avoids updating the superblock write time when we are mounting
> the root file system read/only but we need to replay the journal; at
> that point, for people who are east of GMT and who make their clock
> tick in localtime for Windows bug-for-bug compatibility, and this will
> cause e2fsck to complain and force a full file system check.
>
> Signed-off-by: "Theodore Ts'o" <[email protected]>
Thanks. Added to my tree.

Honza
> ---
> fs/ext3/super.c | 13 ++++++++++++-
> 1 files changed, 12 insertions(+), 1 deletions(-)
>
> diff --git a/fs/ext3/super.c b/fs/ext3/super.c
> index a8d80a7..62c86af 100644
> --- a/fs/ext3/super.c
> +++ b/fs/ext3/super.c
> @@ -2321,7 +2321,18 @@ static int ext3_commit_super(struct super_block *sb,
>
> if (!sbh)
> return error;
> - es->s_wtime = cpu_to_le32(get_seconds());
> + /*
> + * If the file system is mounted read-only, don't update the
> + * superblock write time. This avoids updating the superblock
> + * write time when we are mounting the root file system
> + * read/only but we need to replay the journal; at that point,
> + * for people who are east of GMT and who make their clock
> + * tick in localtime for Windows bug-for-bug compatibility,
> + * the clock is set in the future, and this will cause e2fsck
> + * to complain and force a full file system check.
> + */
> + if (!(sb->s_flags & MS_RDONLY))
> + es->s_wtime = cpu_to_le32(get_seconds());
> es->s_free_blocks_count = cpu_to_le32(ext3_count_free_blocks(sb));
> es->s_free_inodes_count = cpu_to_le32(ext3_count_free_inodes(sb));
> BUFFER_TRACE(sbh, "marking dirty");
> --
> 1.6.3.2.1.gb9f7d.dirty
>
--
Jan Kara <[email protected]>
SUSE Labs, CR

2009-09-17 14:47:00

by Eric Sandeen

Subject: Re: [PATCH] ext3: Don't update superblock write time when filesystem is read-only

Theodore Ts'o wrote:
> This avoids updating the superblock write time when we are mounting
> the root file system read/only but we need to replay the journal; at
> that point, for people who are east of GMT and who make their clock
> tick in localtime for Windows bug-for-bug compatibility, and this will
> cause e2fsck to complain and force a full file system check.

Just out of curiosity, why does e2fsck even care? Why is a fairly
common & explainable time delta the trigger for a full fsck?

It seems like this solution may have some implications for forensics, etc.

Thanks,
-Eric

> Signed-off-by: "Theodore Ts'o" <[email protected]>
> ---
> fs/ext3/super.c | 13 ++++++++++++-
> 1 files changed, 12 insertions(+), 1 deletions(-)
>
> diff --git a/fs/ext3/super.c b/fs/ext3/super.c
> index a8d80a7..62c86af 100644
> --- a/fs/ext3/super.c
> +++ b/fs/ext3/super.c
> @@ -2321,7 +2321,18 @@ static int ext3_commit_super(struct super_block *sb,
>
> if (!sbh)
> return error;
> - es->s_wtime = cpu_to_le32(get_seconds());
> + /*
> + * If the file system is mounted read-only, don't update the
> + * superblock write time. This avoids updating the superblock
> + * write time when we are mounting the root file system
> + * read/only but we need to replay the journal; at that point,
> + * for people who are east of GMT and who make their clock
> + * tick in localtime for Windows bug-for-bug compatibility,
> + * the clock is set in the future, and this will cause e2fsck
> + * to complain and force a full file system check.
> + */
> + if (!(sb->s_flags & MS_RDONLY))
> + es->s_wtime = cpu_to_le32(get_seconds());
> es->s_free_blocks_count = cpu_to_le32(ext3_count_free_blocks(sb));
> es->s_free_inodes_count = cpu_to_le32(ext3_count_free_inodes(sb));
> BUFFER_TRACE(sbh, "marking dirty");