On 11 Aug 2021 at 17:58, "Darrick J. Wong" <djwong@xxxxxxxxxx> wrote:
> From: Darrick J. Wong <djwong@xxxxxxxxxx>
>
> There are several GETFSMAP backend functions for XFS to cover the three
> devices and various feature support. Each of these functions are passed
> pointers to the low and high keys for the dataset that userspace
> requested, and a pointer to scratchpad variables that are used to
> control the iteration and fill out records. The scratchpad data can be
> changed arbitrarily, but the keys are supposed to remain unchanged (and
> under the control of the outermost loop in xfs_getfsmap).
>
> Unfortunately, the data and rt backends modify the keys that are passed
> in from the main control loop, which causes subsequent calls to return
> incorrect query results. Specifically, each of those two functions set
> the block number in the high key to the size of their respective device.
> Since fsmap results are sorted in device number order, if the lower
> numbered device is smaller than the higher numbered device, the first
> function will set the high key to the small size, and the key remains
> unchanged as it is passed into the function for the higher numbered
> device. The second function will then fail to return all of the results
> for the dataset that userspace is asking for because the keyspace is
> incorrectly constrained.
>
Looks good.
Reviewed-by: Chandan Babu R <chandanrlinux@xxxxxxxxx>
> Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
> ---
> fs/xfs/xfs_fsmap.c | 30 +++++++++++++-----------------
> 1 file changed, 13 insertions(+), 17 deletions(-)
>
>
> diff --git a/fs/xfs/xfs_fsmap.c b/fs/xfs/xfs_fsmap.c
> index a0e8ab58124b..7bcc2ab68b8d 100644
> --- a/fs/xfs/xfs_fsmap.c
> +++ b/fs/xfs/xfs_fsmap.c
> @@ -61,7 +61,7 @@ xfs_fsmap_to_internal(
> static int
> xfs_fsmap_owner_to_rmap(
> struct xfs_rmap_irec *dest,
> - struct xfs_fsmap *src)
> + const struct xfs_fsmap *src)
> {
> if (!(src->fmr_flags & FMR_OF_SPECIAL_OWNER)) {
> dest->rm_owner = src->fmr_owner;
> @@ -171,7 +171,7 @@ struct xfs_getfsmap_info {
> struct xfs_getfsmap_dev {
> u32 dev;
> int (*fn)(struct xfs_trans *tp,
> - struct xfs_fsmap *keys,
> + const struct xfs_fsmap *keys,
> struct xfs_getfsmap_info *info);
> };
>
> @@ -389,7 +389,7 @@ xfs_getfsmap_datadev_bnobt_helper(
> static void
> xfs_getfsmap_set_irec_flags(
> struct xfs_rmap_irec *irec,
> - struct xfs_fsmap *fmr)
> + const struct xfs_fsmap *fmr)
> {
> irec->rm_flags = 0;
> if (fmr->fmr_flags & FMR_OF_ATTR_FORK)
> @@ -404,7 +404,7 @@ xfs_getfsmap_set_irec_flags(
> STATIC int
> xfs_getfsmap_logdev(
> struct xfs_trans *tp,
> - struct xfs_fsmap *keys,
> + const struct xfs_fsmap *keys,
> struct xfs_getfsmap_info *info)
> {
> struct xfs_mount *mp = tp->t_mountp;
> @@ -473,7 +473,7 @@ xfs_getfsmap_rtdev_rtbitmap_helper(
> STATIC int
> __xfs_getfsmap_rtdev(
> struct xfs_trans *tp,
> - struct xfs_fsmap *keys,
> + const struct xfs_fsmap *keys,
> int (*query_fn)(struct xfs_trans *,
> struct xfs_getfsmap_info *),
> struct xfs_getfsmap_info *info)
> @@ -481,16 +481,14 @@ __xfs_getfsmap_rtdev(
> struct xfs_mount *mp = tp->t_mountp;
> xfs_fsblock_t start_fsb;
> xfs_fsblock_t end_fsb;
> - xfs_daddr_t eofs;
> + uint64_t eofs;
> int error = 0;
>
> eofs = XFS_FSB_TO_BB(mp, mp->m_sb.sb_rblocks);
> if (keys[0].fmr_physical >= eofs)
> return 0;
> - if (keys[1].fmr_physical >= eofs)
> - keys[1].fmr_physical = eofs - 1;
> start_fsb = XFS_BB_TO_FSBT(mp, keys[0].fmr_physical);
> - end_fsb = XFS_BB_TO_FSB(mp, keys[1].fmr_physical);
> + end_fsb = XFS_BB_TO_FSB(mp, min(eofs - 1, keys[1].fmr_physical));
>
> /* Set up search keys */
> info->low.rm_startblock = start_fsb;
> @@ -563,7 +561,7 @@ xfs_getfsmap_rtdev_rtbitmap_query(
> STATIC int
> xfs_getfsmap_rtdev_rtbitmap(
> struct xfs_trans *tp,
> - struct xfs_fsmap *keys,
> + const struct xfs_fsmap *keys,
> struct xfs_getfsmap_info *info)
> {
> info->missing_owner = XFS_FMR_OWN_UNKNOWN;
> @@ -576,7 +574,7 @@ xfs_getfsmap_rtdev_rtbitmap(
> STATIC int
> __xfs_getfsmap_datadev(
> struct xfs_trans *tp,
> - struct xfs_fsmap *keys,
> + const struct xfs_fsmap *keys,
> struct xfs_getfsmap_info *info,
> int (*query_fn)(struct xfs_trans *,
> struct xfs_getfsmap_info *,
> @@ -591,16 +589,14 @@ __xfs_getfsmap_datadev(
> xfs_fsblock_t end_fsb;
> xfs_agnumber_t start_ag;
> xfs_agnumber_t end_ag;
> - xfs_daddr_t eofs;
> + uint64_t eofs;
> int error = 0;
>
> eofs = XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks);
> if (keys[0].fmr_physical >= eofs)
> return 0;
> - if (keys[1].fmr_physical >= eofs)
> - keys[1].fmr_physical = eofs - 1;
> start_fsb = XFS_DADDR_TO_FSB(mp, keys[0].fmr_physical);
> - end_fsb = XFS_DADDR_TO_FSB(mp, keys[1].fmr_physical);
> + end_fsb = XFS_DADDR_TO_FSB(mp, min(eofs - 1, keys[1].fmr_physical));
>
> /*
> * Convert the fsmap low/high keys to AG based keys. Initialize
> @@ -728,7 +724,7 @@ xfs_getfsmap_datadev_rmapbt_query(
> STATIC int
> xfs_getfsmap_datadev_rmapbt(
> struct xfs_trans *tp,
> - struct xfs_fsmap *keys,
> + const struct xfs_fsmap *keys,
> struct xfs_getfsmap_info *info)
> {
> info->missing_owner = XFS_FMR_OWN_FREE;
> @@ -763,7 +759,7 @@ xfs_getfsmap_datadev_bnobt_query(
> STATIC int
> xfs_getfsmap_datadev_bnobt(
> struct xfs_trans *tp,
> - struct xfs_fsmap *keys,
> + const struct xfs_fsmap *keys,
> struct xfs_getfsmap_info *info)
> {
> struct xfs_alloc_rec_incore akeys[2];
--
chandan
