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Date: Wed, 12 Apr 2017 15:00:04 -0600
From: Andreas Dilger <adilger@...ger.ca>
To: Jan Kara <jack@...e.cz>
Cc: linux-fsdevel@...r.kernel.org, linux-ext4@...r.kernel.org,
reiserfs-devel@...r.kernel.org,
jfs-discussion@...ts.sourceforge.net
Subject: Re: [PATCH 01/11] ext4: Set flags on quota files directly
On Apr 12, 2017, at 1:26 AM, Jan Kara <jack@...e.cz> wrote:
>
> Currently immutable and noatime flags on quota files are set by quota
> code which requires us to copy inode->i_flags to our on disk version of
> quota flags in GETFLAGS ioctl and ext4_do_update_inode(). Move to
> setting / clearing these on-disk flags directly to save that copying.
>
> Signed-off-by: Jan Kara <jack@...e.cz>
> ---
> fs/ext4/super.c | 62 +++++++++++++++++++++++++++++++++++++++++++++++++++------
> 1 file changed, 56 insertions(+), 6 deletions(-)
>
> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index a9448db1cf7e..480cbbebdc57 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -839,6 +839,28 @@ static void dump_orphan_list(struct super_block *sb, struct ext4_sb_info *sbi)
> }
> }
>
> +#ifdef CONFIG_QUOTA
> +static int ext4_quota_off(struct super_block *sb, int type);
> +
> +static inline void ext4_quota_off_umount(struct super_block *sb)
> +{
> + int type;
> +
> + if (ext4_has_feature_quota(sb)) {
> + dquot_disable(sb, -1,
> + DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
> + } else {
> + /* Use our quota_off function to clear inode flags etc. */
> + for (type = 0; type < EXT4_MAXQUOTAS; type++)
> + ext4_quota_off(sb, type);
> + }
> +}
> +#else
> +static inline void ext4_quota_off_umount(struct super_block *sb)
> +{
> +}
> +#endif
> +
> static void ext4_put_super(struct super_block *sb)
> {
> struct ext4_sb_info *sbi = EXT4_SB(sb);
> @@ -847,7 +869,7 @@ static void ext4_put_super(struct super_block *sb)
> int i, err;
>
> ext4_unregister_li_request(sb);
> - dquot_disable(sb, -1, DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
> + ext4_quota_off_umount(sb);
>
> flush_workqueue(sbi->rsv_conversion_wq);
> destroy_workqueue(sbi->rsv_conversion_wq);
> @@ -1218,7 +1240,6 @@ static int ext4_mark_dquot_dirty(struct dquot *dquot);
> static int ext4_write_info(struct super_block *sb, int type);
> static int ext4_quota_on(struct super_block *sb, int type, int format_id,
> const struct path *path);
> -static int ext4_quota_off(struct super_block *sb, int type);
> static int ext4_quota_on_mount(struct super_block *sb, int type);
> static ssize_t ext4_quota_read(struct super_block *sb, int type, char *data,
> size_t len, loff_t off);
> @@ -5344,11 +5365,28 @@ static int ext4_quota_on(struct super_block *sb, int type, int format_id,
> if (err)
> return err;
> }
> +
> lockdep_set_quota_inode(path->dentry->d_inode, I_DATA_SEM_QUOTA);
> err = dquot_quota_on(sb, type, format_id, path);
> - if (err)
> + if (err) {
> lockdep_set_quota_inode(path->dentry->d_inode,
> I_DATA_SEM_NORMAL);
> + } else {
> + struct inode *inode = d_inode(path->dentry);
> + handle_t *handle;
> +
> + inode_lock(inode);
> + handle = ext4_journal_start(inode, EXT4_HT_QUOTA, 1);
> + if (IS_ERR(handle))
> + goto unlock_inode;
> + EXT4_I(inode)->i_flags |= EXT4_NOATIME_FL | EXT4_IMMUTABLE_FL;
> + inode_set_flags(inode, S_NOATIME | S_IMMUTABLE,
> + S_NOATIME | S_IMMUTABLE);
> + ext4_mark_inode_dirty(handle, inode);
> + ext4_journal_stop(handle);
Should this be conditional on these flags not already being set? Otherwise
it dirties the filesystem on every mount even if it isn't needed.
> + unlock_inode:
> + inode_unlock(inode);
> + }
> return err;
> }
>
> @@ -5422,24 +5460,36 @@ static int ext4_quota_off(struct super_block *sb, int type)
> {
> struct inode *inode = sb_dqopt(sb)->files[type];
> handle_t *handle;
> + int err;
>
> /* Force all delayed allocation blocks to be allocated.
> * Caller already holds s_umount sem */
> if (test_opt(sb, DELALLOC))
> sync_filesystem(sb);
>
> - if (!inode)
> + if (!inode || !igrab(inode))
> goto out;
>
> + err = dquot_quota_off(sb, type);
> + if (err)
> + goto out_put;
> +
> + inode_lock(inode);
> /* Update modification times of quota files when userspace can
> * start looking at them */
> handle = ext4_journal_start(inode, EXT4_HT_QUOTA, 1);
> if (IS_ERR(handle))
> - goto out;
> + goto out_unlock;
> + EXT4_I(inode)->i_flags &= ~(EXT4_NOATIME_FL | EXT4_IMMUTABLE_FL);
> + inode_set_flags(inode, 0, S_NOATIME | S_IMMUTABLE);
It isn't obvious that we need to clear these flags at every unmount? I
don't think there is a good reason to be modifying the quota files from
userspace, and e2fsck won't care about these flags anyway when fixing
the quota files.
> inode->i_mtime = inode->i_ctime = current_time(inode);
> ext4_mark_inode_dirty(handle, inode);
> ext4_journal_stop(handle);
> -
> +out_unlock:
> + inode_unlock(inode);
> +out_put:
> + iput(inode);
> + return err;
> out:
> return dquot_quota_off(sb, type);
> }
> --
> 2.12.0
>
Cheers, Andreas
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