On Fri, Dec 04, 2020 at 12:10:26AM +0800, Gao Xiang wrote:
> From: Dave Chinner <dchinner@xxxxxxxxxx>
>
> Get rid of the confusing ialloc_context and failure handling around
> xfs_dialloc() by moving xfs_dialloc_roll() into xfs_dialloc().
>
> Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
> Signed-off-by: Gao Xiang <hsiangkao@xxxxxxxxxx>
Heh. I sent my comments about to patch 4 as a reply to patch 3. :(
Well, at least the critical part is the same between both:
Reviewed-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
--D
> ---
> fs/xfs/libxfs/xfs_ialloc.c | 57 ++++++++++++--------------------------
> fs/xfs/libxfs/xfs_ialloc.h | 22 +--------------
> fs/xfs/xfs_inode.c | 24 +---------------
> 3 files changed, 20 insertions(+), 83 deletions(-)
>
> diff --git a/fs/xfs/libxfs/xfs_ialloc.c b/fs/xfs/libxfs/xfs_ialloc.c
> index d5dc3167e2ff..d2d7378abf49 100644
> --- a/fs/xfs/libxfs/xfs_ialloc.c
> +++ b/fs/xfs/libxfs/xfs_ialloc.c
> @@ -1682,7 +1682,7 @@ xfs_dialloc_ag(
> return error;
> }
>
> -int
> +static int
> xfs_dialloc_roll(
> struct xfs_trans **tpp,
> struct xfs_buf *agibp)
> @@ -1733,30 +1733,18 @@ xfs_dialloc_roll(
> * Mode is used to tell whether the new inode will need space, and whether it
> * is a directory.
> *
> - * This function is designed to be called twice if it has to do an allocation
> - * to make more free inodes. On the first call, *IO_agbp should be set to NULL.
> - * If an inode is available without having to performn an allocation, an inode
> - * number is returned. In this case, *IO_agbp is set to NULL. If an allocation
> - * needs to be done, xfs_dialloc returns the current AGI buffer in *IO_agbp.
> - * The caller should then commit the current transaction, allocate a
> - * new transaction, and call xfs_dialloc() again, passing in the previous value
> - * of *IO_agbp. IO_agbp should be held across the transactions. Since the AGI
> - * buffer is locked across the two calls, the second call is guaranteed to have
> - * a free inode available.
> - *
> * Once we successfully pick an inode its number is returned and the on-disk
> * data structures are updated. The inode itself is not read in, since doing so
> * would break ordering constraints with xfs_reclaim.
> */
> int
> xfs_dialloc(
> - struct xfs_trans *tp,
> + struct xfs_trans **tpp,
> xfs_ino_t parent,
> umode_t mode,
> - struct xfs_buf **IO_agbp,
> xfs_ino_t *inop)
> {
> - struct xfs_mount *mp = tp->t_mountp;
> + struct xfs_mount *mp = (*tpp)->t_mountp;
> struct xfs_buf *agbp;
> xfs_agnumber_t agno;
> int error;
> @@ -1767,21 +1755,11 @@ xfs_dialloc(
> struct xfs_ino_geometry *igeo = M_IGEO(mp);
> bool okalloc = true;
>
> - if (*IO_agbp) {
> - /*
> - * If the caller passes in a pointer to the AGI buffer,
> - * continue where we left off before. In this case, we
> - * know that the allocation group has free inodes.
> - */
> - agbp = *IO_agbp;
> - goto out_alloc;
> - }
> -
> /*
> * We do not have an agbp, so select an initial allocation
> * group for inode allocation.
> */
> - start_agno = xfs_ialloc_ag_select(tp, parent, mode);
> + start_agno = xfs_ialloc_ag_select(*tpp, parent, mode);
> if (start_agno == NULLAGNUMBER) {
> *inop = NULLFSINO;
> return 0;
> @@ -1816,7 +1794,7 @@ xfs_dialloc(
> }
>
> if (!pag->pagi_init) {
> - error = xfs_ialloc_pagi_init(mp, tp, agno);
> + error = xfs_ialloc_pagi_init(mp, *tpp, agno);
> if (error)
> goto out_error;
> }
> @@ -1831,7 +1809,7 @@ xfs_dialloc(
> * Then read in the AGI buffer and recheck with the AGI buffer
> * lock held.
> */
> - error = xfs_ialloc_read_agi(mp, tp, agno, &agbp);
> + error = xfs_ialloc_read_agi(mp, *tpp, agno, &agbp);
> if (error)
> goto out_error;
>
> @@ -1844,9 +1822,9 @@ xfs_dialloc(
> goto nextag_relse_buffer;
>
>
> - error = xfs_ialloc_ag_alloc(tp, agbp, &ialloced);
> + error = xfs_ialloc_ag_alloc(*tpp, agbp, &ialloced);
> if (error) {
> - xfs_trans_brelse(tp, agbp);
> + xfs_trans_brelse(*tpp, agbp);
>
> if (error != -ENOSPC)
> goto out_error;
> @@ -1858,21 +1836,23 @@ xfs_dialloc(
>
> if (ialloced) {
> /*
> - * We successfully allocated some inodes, return
> - * the current context to the caller so that it
> - * can commit the current transaction and call
> - * us again where we left off.
> + * We successfully allocated some inodes, roll the
> + * transaction so they can allocate one of the free
> + * inodes we just prepared for them.
> */
> ASSERT(pag->pagi_freecount > 0);
> xfs_perag_put(pag);
>
> - *IO_agbp = agbp;
> + error = xfs_dialloc_roll(tpp, agbp);
> + if (error)
> + return error;
> +
> *inop = NULLFSINO;
> - return 0;
> + goto out_alloc;
> }
>
> nextag_relse_buffer:
> - xfs_trans_brelse(tp, agbp);
> + xfs_trans_brelse(*tpp, agbp);
> nextag:
> xfs_perag_put(pag);
> if (++agno == mp->m_sb.sb_agcount)
> @@ -1884,8 +1864,7 @@ xfs_dialloc(
> }
>
> out_alloc:
> - *IO_agbp = NULL;
> - return xfs_dialloc_ag(tp, agbp, parent, inop);
> + return xfs_dialloc_ag(*tpp, agbp, parent, inop);
> out_error:
> xfs_perag_put(pag);
> return error;
> diff --git a/fs/xfs/libxfs/xfs_ialloc.h b/fs/xfs/libxfs/xfs_ialloc.h
> index a145e2a72530..13810ffe4af9 100644
> --- a/fs/xfs/libxfs/xfs_ialloc.h
> +++ b/fs/xfs/libxfs/xfs_ialloc.h
> @@ -32,40 +32,20 @@ xfs_make_iptr(struct xfs_mount *mp, struct xfs_buf *b, int o)
> return xfs_buf_offset(b, o << (mp)->m_sb.sb_inodelog);
> }
>
> -/* XXX: will be removed in the following patch */
> -int
> -xfs_dialloc_roll(
> - struct xfs_trans **tpp,
> - struct xfs_buf *agibp);
> -
> /*
> * Allocate an inode on disk.
> * Mode is used to tell whether the new inode will need space, and whether
> * it is a directory.
> *
> - * To work within the constraint of one allocation per transaction,
> - * xfs_dialloc() is designed to be called twice if it has to do an
> - * allocation to make more free inodes. If an inode is
> - * available without an allocation, agbp would be set to the current
> - * agbp and alloc_done set to false.
> - * If an allocation needed to be done, agbp would be set to the
> - * inode header of the allocation group and alloc_done set to true.
> - * The caller should then commit the current transaction and allocate a new
> - * transaction. xfs_dialloc() should then be called again with
> - * the agbp value returned from the previous call.
> - *
> * Once we successfully pick an inode its number is returned and the
> * on-disk data structures are updated. The inode itself is not read
> * in, since doing so would break ordering constraints with xfs_reclaim.
> - *
> - * *agbp should be set to NULL on the first call, *alloc_done set to FALSE.
> */
> int /* error */
> xfs_dialloc(
> - struct xfs_trans *tp, /* transaction pointer */
> + struct xfs_trans **tpp, /* double pointer of transaction */
> xfs_ino_t parent, /* parent inode (directory) */
> umode_t mode, /* mode bits for new inode */
> - struct xfs_buf **agbp, /* buf for a.g. inode header */
> xfs_ino_t *inop); /* inode number allocated */
>
> /*
> diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
> index 34eca1624397..c039fc56b396 100644
> --- a/fs/xfs/xfs_inode.c
> +++ b/fs/xfs/xfs_inode.c
> @@ -909,7 +909,6 @@ xfs_dir_ialloc(
> locked. */
> {
> xfs_inode_t *ip;
> - xfs_buf_t *ialloc_context = NULL;
> xfs_ino_t pino = dp ? dp->i_ino : 0;
> xfs_ino_t ino;
> int error;
> @@ -928,31 +927,10 @@ xfs_dir_ialloc(
> * commit so that no other process can steal the inode(s) that we've
> * just allocated.
> */
> - error = xfs_dialloc(*tpp, pino, mode, ialloc_context, &ino);
> + error = xfs_dialloc(tpp, pino, mode, &ino);
> if (error)
> return error;
>
> - /*
> - * If the AGI buffer is non-NULL, then we were unable to get an
> - * inode in one operation. We need to commit the current
> - * transaction and call xfs_ialloc() then. It is guaranteed
> - * to succeed the second time.
> - */
> - if (ialloc_context) {
> - error = xfs_dialloc_roll(tpp, ialloc_context);
> - if (error)
> - return error;
> - /*
> - * Call dialloc again. Since we've locked out all other
> - * allocations in this allocation group, this call should
> - * always succeed.
> - */
> - error = xfs_dialloc(*tpp, pino, mode, ialloc_context, &ino);
> - if (error)
> - return error;
> - ASSERT(!ialloc_context);
> - }
> -
> if (ino == NULLFSINO)
> return -ENOSPC;
>
> --
> 2.18.4
>
