On Thu, Jul 11, 2013 at 12:00:42AM -0500, Chandra Seetharaman wrote:
> Added appropriate pads and code for backward compatibility.
>
> Copied over the old version as it is different from the newer padded
> version.
>
> New callers of the system call have to set the version of the data
> structure being passed, and kernel will fill as much data as requested.
>
> Signed-off-by: Chandra Seetharaman <sekharan@xxxxxxxxxx>
> ---
> fs/gfs2/quota.c | 3 --
> fs/quota/quota.c | 67 +++++++++++++++++++++++++++++++++++++--
> fs/xfs/xfs_qm_syscalls.c | 4 --
> include/uapi/linux/dqblk_xfs.h | 60 +++++++++++++++++++++++++++++++----
> 4 files changed, 116 insertions(+), 18 deletions(-)
>
> diff --git a/fs/gfs2/quota.c b/fs/gfs2/quota.c
> index c7c840e..ca0dccd 100644
> --- a/fs/gfs2/quota.c
> +++ b/fs/gfs2/quota.c
> @@ -1443,9 +1443,6 @@ static int gfs2_quota_get_xstate(struct super_block *sb,
> {
> struct gfs2_sbd *sdp = sb->s_fs_info;
>
> - memset(fqs, 0, sizeof(struct fs_quota_stat));
> - fqs->qs_version = FS_QSTAT_VERSION;
> -
> switch (sdp->sd_args.ar_quota) {
> case GFS2_QUOTA_ON:
> fqs->qs_flags |= (FS_QUOTA_UDQ_ENFD | FS_QUOTA_GDQ_ENFD);
> diff --git a/fs/quota/quota.c b/fs/quota/quota.c
> index c7314f1..ac5dd3a 100644
> --- a/fs/quota/quota.c
> +++ b/fs/quota/quota.c
> @@ -204,15 +204,72 @@ static int quota_setxstate(struct super_block *sb, int cmd, void __user *addr)
> return sb->s_qcop->set_xstate(sb, flags, cmd);
> }
>
> -static int quota_getxstate(struct super_block *sb, void __user *addr)
> +static int quota_getxstate(struct super_block *sb, void __user *addr,
> + bool older_version)
I'd suggest that the two API calls should be handled by separate
functions so there are no overlapping, dependent branches in the
code.
> {
> struct fs_quota_stat fqs;
> - int ret;
> + struct fs_quota_stat_v1 fqs_v1;
> + int ret, size;
> + void *fqsp;
>
> if (!sb->s_qcop->get_xstate)
> return -ENOSYS;
I'd also suggest that a sb->s_qcop->get_xstatev vector is added
so that filesystems keep the separate as well.
And that means we don't need to play the fs_quota_stat and
conversion-to-fs_quota_stat_v1 games. i.e. the existing
quota_getxstate() remains and uses the existing struct
fs_quota_stat, and the new Q_XGETQSTATV calls quota_getxstatev() and
uses the newly defined struct fs_quota_statv and ->get_xstatev()
call....
> @@ -137,31 +139,75 @@ typedef struct fs_disk_quota {
> * Provides a centralized way to get meta information about the quota subsystem.
> * eg. space taken up for user and group quotas, number of dquots currently
> * incore.
> + * With version FS_QSTAT_VERSION, user space can send in an uninitialized
> + * buffer and data will be filled by the kernel.
> + * Starting FS_QSTAT_VERSION_2, to be used with Q_XGETQSTATV, user space
> + * caller should set qs_version to the appropriate version of the
> + * fs_quota_stat data structure they are providing. On return, user
> + * space should check qs_version and use appropriate fields supported by
> + * that version.
> */
> #define FS_QSTAT_VERSION 1 /* fs_quota_stat.qs_version */
> +#define FS_QSTAT_VERSION_2 2 /* new field qs_pquota; realignment */
As per above, this reasoning and logic is all invalid now because we
aren't trying to maintain compatibility between users of the same
quotactl.
We are using a new quotactl, so we do not need to overload the
existing structure or versions.
> +/*
> + * Some basic information about 'quota files'. Version 2.
> + */
> +struct fs_qfilestat {
> + __u64 qfs_ino; /* inode number */
> + __u64 qfs_nblks; /* number of BBs 512-byte-blks */
> + __u32 qfs_nextents; /* number of extents */
> + __u32 qfs_pad; /* pad for 8-byte alignment */
> +};
> +
> +struct fs_quota_stat {
> + __s8 qs_version; /* version for future changes */
> + __u8 qs_pad1; /* pad for 16bit alignment */
> + __u16 qs_flags; /* FS_QUOTA_.* flags */
> + __u32 qs_incoredqs; /* number of dquots incore */
> + struct fs_qfilestat qs_uquota; /* user quota information */
> + struct fs_qfilestat qs_gquota; /* group quota information */
> + struct fs_qfilestat qs_pquota; /* project quota information */
> + __s32 qs_btimelimit; /* limit for blks timer */
> + __s32 qs_itimelimit; /* limit for inodes timer */
> + __s32 qs_rtbtimelimit;/* limit for rt blks timer */
> + __u16 qs_bwarnlimit; /* limit for num warnings */
> + __u16 qs_iwarnlimit; /* limit for num warnings */
> + __u64 qs_pad2[8]; /* for future proofing */
> +};
these are what become fs_quota_statv and fs_qfilestatv structures
for the new quotactl.
> +/*
> + * Since Version 1 did not have padding at appropriate places,
> + * a new data structure has been defined for the older version to
> + * provide backward compatibility.
> + * Future extentions of this data structure won't require new
> + * data structure definitions as the current one can be extended
> + * with the logic and padding in place now.
> + */
> +#define FS_QSTAT_V1_SIZE (sizeof(struct fs_quota_stat_v1))
> +#define FS_QSTAT_V2_SIZE (sizeof(struct fs_quota_stat))
And these can go away completely.
Cheers,
Dave.
--
Dave Chinner
david@xxxxxxxxxxxxx
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