| Message ID | 20210305025703.3069469-5-hsiangkao@redhat.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | xfs: support shrinking free space in the last AG | expand |
On Fri, Mar 05, 2021 at 10:57:02AM +0800, Gao Xiang wrote: > As the first step of shrinking, this attempts to enable shrinking > unused space in the last allocation group by fixing up freespace > btree, agi, agf and adjusting super block and use a helper > xfs_ag_shrink_space() to fixup the last AG. > > This can be all done in one transaction for now, so I think no > additional protection is needed. > > Reviewed-by: Darrick J. Wong <djwong@kernel.org> > Signed-off-by: Gao Xiang <hsiangkao@redhat.com> > --- > fs/xfs/xfs_fsops.c | 88 ++++++++++++++++++++++++++++------------------ > fs/xfs/xfs_trans.c | 1 - > 2 files changed, 53 insertions(+), 36 deletions(-) > > diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c > index fc9e799b2ae3..71cba61a451c 100644 > --- a/fs/xfs/xfs_fsops.c > +++ b/fs/xfs/xfs_fsops.c > @@ -91,23 +91,28 @@ xfs_growfs_data_private( > xfs_agnumber_t nagcount; > xfs_agnumber_t nagimax = 0; > xfs_rfsblock_t nb, nb_div, nb_mod; > - xfs_rfsblock_t delta; > + int64_t delta; > bool lastag_resetagres; > xfs_agnumber_t oagcount; > struct xfs_trans *tp; > struct aghdr_init_data id = {}; > > nb = in->newblocks; > - if (nb < mp->m_sb.sb_dblocks) > - return -EINVAL; > - if ((error = xfs_sb_validate_fsb_count(&mp->m_sb, nb))) > + if (nb == mp->m_sb.sb_dblocks) > + return 0; It looks like the caller already does this check. > + > + error = xfs_sb_validate_fsb_count(&mp->m_sb, nb); > + if (error) > return error; > - error = xfs_buf_read_uncached(mp->m_ddev_targp, > + > + if (nb > mp->m_sb.sb_dblocks) { > + error = xfs_buf_read_uncached(mp->m_ddev_targp, > XFS_FSB_TO_BB(mp, nb) - XFS_FSS_TO_BB(mp, 1), > XFS_FSS_TO_BB(mp, 1), 0, &bp, NULL); > - if (error) > - return error; > - xfs_buf_relse(bp); > + if (error) > + return error; > + xfs_buf_relse(bp); > + } > > nb_div = nb; > nb_mod = do_div(nb_div, mp->m_sb.sb_agblocks); > @@ -115,10 +120,15 @@ xfs_growfs_data_private( > if (nb_mod && nb_mod < XFS_MIN_AG_BLOCKS) { > nagcount--; > nb = (xfs_rfsblock_t)nagcount * mp->m_sb.sb_agblocks; > - if (nb < mp->m_sb.sb_dblocks) > - return -EINVAL; > } > delta = nb - mp->m_sb.sb_dblocks; > + /* > + * XFS doesn't really support single-AG filesystems, so do not > + * permit callers to remove the filesystem's second and last AG. > + */ > + if (delta < 0 && nagcount < 2) > + return -EINVAL; > + What if the filesystem is already single AG? Unless I'm missing something, we already have a check a bit further down that prevents removal of AGs in the first place. Otherwise looks reasonable.. Brian > oagcount = mp->m_sb.sb_agcount; > > /* allocate the new per-ag structures */ > @@ -126,15 +136,22 @@ xfs_growfs_data_private( > error = xfs_initialize_perag(mp, nagcount, &nagimax); > if (error) > return error; > + } else if (nagcount < oagcount) { > + /* TODO: shrinking the entire AGs hasn't yet completed */ > + return -EINVAL; > } > > error = xfs_trans_alloc(mp, &M_RES(mp)->tr_growdata, > - XFS_GROWFS_SPACE_RES(mp), 0, XFS_TRANS_RESERVE, &tp); > + (delta > 0 ? XFS_GROWFS_SPACE_RES(mp) : -delta), 0, > + XFS_TRANS_RESERVE, &tp); > if (error) > return error; > > - error = xfs_resizefs_init_new_ags(tp, &id, oagcount, nagcount, > - delta, &lastag_resetagres); > + if (delta > 0) > + error = xfs_resizefs_init_new_ags(tp, &id, oagcount, nagcount, > + delta, &lastag_resetagres); > + else > + error = xfs_ag_shrink_space(mp, &tp, nagcount - 1, -delta); > if (error) > goto out_trans_cancel; > > @@ -145,7 +162,7 @@ xfs_growfs_data_private( > */ > if (nagcount > oagcount) > xfs_trans_mod_sb(tp, XFS_TRANS_SB_AGCOUNT, nagcount - oagcount); > - if (delta > 0) > + if (delta) > xfs_trans_mod_sb(tp, XFS_TRANS_SB_DBLOCKS, delta); > if (id.nfree) > xfs_trans_mod_sb(tp, XFS_TRANS_SB_FDBLOCKS, id.nfree); > @@ -169,28 +186,29 @@ xfs_growfs_data_private( > xfs_set_low_space_thresholds(mp); > mp->m_alloc_set_aside = xfs_alloc_set_aside(mp); > > - /* > - * If we expanded the last AG, free the per-AG reservation > - * so we can reinitialize it with the new size. > - */ > - if (lastag_resetagres) { > - struct xfs_perag *pag; > - > - pag = xfs_perag_get(mp, id.agno); > - error = xfs_ag_resv_free(pag); > - xfs_perag_put(pag); > - if (error) > - return error; > + if (delta > 0) { > + /* > + * If we expanded the last AG, free the per-AG reservation > + * so we can reinitialize it with the new size. > + */ > + if (lastag_resetagres) { > + struct xfs_perag *pag; > + > + pag = xfs_perag_get(mp, id.agno); > + error = xfs_ag_resv_free(pag); > + xfs_perag_put(pag); > + if (error) > + return error; > + } > + /* > + * Reserve AG metadata blocks. ENOSPC here does not mean there > + * was a growfs failure, just that there still isn't space for > + * new user data after the grow has been run. > + */ > + error = xfs_fs_reserve_ag_blocks(mp); > + if (error == -ENOSPC) > + error = 0; > } > - > - /* > - * Reserve AG metadata blocks. ENOSPC here does not mean there was a > - * growfs failure, just that there still isn't space for new user data > - * after the grow has been run. > - */ > - error = xfs_fs_reserve_ag_blocks(mp); > - if (error == -ENOSPC) > - error = 0; > return error; > > out_trans_cancel: > diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c > index 44f72c09c203..d047f5f26cc0 100644 > --- a/fs/xfs/xfs_trans.c > +++ b/fs/xfs/xfs_trans.c > @@ -434,7 +434,6 @@ xfs_trans_mod_sb( > tp->t_res_frextents_delta += delta; > break; > case XFS_TRANS_SB_DBLOCKS: > - ASSERT(delta > 0); > tp->t_dblocks_delta += delta; > break; > case XFS_TRANS_SB_AGCOUNT: > -- > 2.27.0 >
On Mon, Mar 22, 2021 at 07:30:40AM -0400, Brian Foster wrote: > On Fri, Mar 05, 2021 at 10:57:02AM +0800, Gao Xiang wrote: > > As the first step of shrinking, this attempts to enable shrinking > > unused space in the last allocation group by fixing up freespace > > btree, agi, agf and adjusting super block and use a helper > > xfs_ag_shrink_space() to fixup the last AG. > > > > This can be all done in one transaction for now, so I think no > > additional protection is needed. > > > > Reviewed-by: Darrick J. Wong <djwong@kernel.org> > > Signed-off-by: Gao Xiang <hsiangkao@redhat.com> > > --- > > fs/xfs/xfs_fsops.c | 88 ++++++++++++++++++++++++++++------------------ > > fs/xfs/xfs_trans.c | 1 - > > 2 files changed, 53 insertions(+), 36 deletions(-) > > > > diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c > > index fc9e799b2ae3..71cba61a451c 100644 > > --- a/fs/xfs/xfs_fsops.c > > +++ b/fs/xfs/xfs_fsops.c > > @@ -91,23 +91,28 @@ xfs_growfs_data_private( > > xfs_agnumber_t nagcount; > > xfs_agnumber_t nagimax = 0; > > xfs_rfsblock_t nb, nb_div, nb_mod; > > - xfs_rfsblock_t delta; > > + int64_t delta; > > bool lastag_resetagres; > > xfs_agnumber_t oagcount; > > struct xfs_trans *tp; > > struct aghdr_init_data id = {}; > > > > nb = in->newblocks; > > - if (nb < mp->m_sb.sb_dblocks) > > - return -EINVAL; > > - if ((error = xfs_sb_validate_fsb_count(&mp->m_sb, nb))) > > + if (nb == mp->m_sb.sb_dblocks) > > + return 0; > > It looks like the caller already does this check. yeah, will remove it. Thanks for pointing out. > > > + > > + error = xfs_sb_validate_fsb_count(&mp->m_sb, nb); > > + if (error) > > return error; > > - error = xfs_buf_read_uncached(mp->m_ddev_targp, > > + > > + if (nb > mp->m_sb.sb_dblocks) { > > + error = xfs_buf_read_uncached(mp->m_ddev_targp, > > XFS_FSB_TO_BB(mp, nb) - XFS_FSS_TO_BB(mp, 1), > > XFS_FSS_TO_BB(mp, 1), 0, &bp, NULL); > > - if (error) > > - return error; > > - xfs_buf_relse(bp); > > + if (error) > > + return error; > > + xfs_buf_relse(bp); > > + } > > > > nb_div = nb; > > nb_mod = do_div(nb_div, mp->m_sb.sb_agblocks); > > @@ -115,10 +120,15 @@ xfs_growfs_data_private( > > if (nb_mod && nb_mod < XFS_MIN_AG_BLOCKS) { > > nagcount--; > > nb = (xfs_rfsblock_t)nagcount * mp->m_sb.sb_agblocks; > > - if (nb < mp->m_sb.sb_dblocks) > > - return -EINVAL; > > } > > delta = nb - mp->m_sb.sb_dblocks; > > + /* > > + * XFS doesn't really support single-AG filesystems, so do not > > + * permit callers to remove the filesystem's second and last AG. > > + */ > > + if (delta < 0 && nagcount < 2) > > + return -EINVAL; > > + > > What if the filesystem is already single AG? Unless I'm missing > something, we already have a check a bit further down that prevents > removal of AGs in the first place. I think it tends to forbid (return -EINVAL) shrinking the filesystem with a single AG only? Am I missing something? Thanks, Gao Xiang > > Otherwise looks reasonable.. > > Brian > > > oagcount = mp->m_sb.sb_agcount; > > > > /* allocate the new per-ag structures */ > > @@ -126,15 +136,22 @@ xfs_growfs_data_private( > > error = xfs_initialize_perag(mp, nagcount, &nagimax); > > if (error) > > return error; > > + } else if (nagcount < oagcount) { > > + /* TODO: shrinking the entire AGs hasn't yet completed */ > > + return -EINVAL; > > } > > > > error = xfs_trans_alloc(mp, &M_RES(mp)->tr_growdata, > > - XFS_GROWFS_SPACE_RES(mp), 0, XFS_TRANS_RESERVE, &tp); > > + (delta > 0 ? XFS_GROWFS_SPACE_RES(mp) : -delta), 0, > > + XFS_TRANS_RESERVE, &tp); > > if (error) > > return error; > > > > - error = xfs_resizefs_init_new_ags(tp, &id, oagcount, nagcount, > > - delta, &lastag_resetagres); > > + if (delta > 0) > > + error = xfs_resizefs_init_new_ags(tp, &id, oagcount, nagcount, > > + delta, &lastag_resetagres); > > + else > > + error = xfs_ag_shrink_space(mp, &tp, nagcount - 1, -delta); > > if (error) > > goto out_trans_cancel; > > > > @@ -145,7 +162,7 @@ xfs_growfs_data_private( > > */ > > if (nagcount > oagcount) > > xfs_trans_mod_sb(tp, XFS_TRANS_SB_AGCOUNT, nagcount - oagcount); > > - if (delta > 0) > > + if (delta) > > xfs_trans_mod_sb(tp, XFS_TRANS_SB_DBLOCKS, delta); > > if (id.nfree) > > xfs_trans_mod_sb(tp, XFS_TRANS_SB_FDBLOCKS, id.nfree); > > @@ -169,28 +186,29 @@ xfs_growfs_data_private( > > xfs_set_low_space_thresholds(mp); > > mp->m_alloc_set_aside = xfs_alloc_set_aside(mp); > > > > - /* > > - * If we expanded the last AG, free the per-AG reservation > > - * so we can reinitialize it with the new size. > > - */ > > - if (lastag_resetagres) { > > - struct xfs_perag *pag; > > - > > - pag = xfs_perag_get(mp, id.agno); > > - error = xfs_ag_resv_free(pag); > > - xfs_perag_put(pag); > > - if (error) > > - return error; > > + if (delta > 0) { > > + /* > > + * If we expanded the last AG, free the per-AG reservation > > + * so we can reinitialize it with the new size. > > + */ > > + if (lastag_resetagres) { > > + struct xfs_perag *pag; > > + > > + pag = xfs_perag_get(mp, id.agno); > > + error = xfs_ag_resv_free(pag); > > + xfs_perag_put(pag); > > + if (error) > > + return error; > > + } > > + /* > > + * Reserve AG metadata blocks. ENOSPC here does not mean there > > + * was a growfs failure, just that there still isn't space for > > + * new user data after the grow has been run. > > + */ > > + error = xfs_fs_reserve_ag_blocks(mp); > > + if (error == -ENOSPC) > > + error = 0; > > } > > - > > - /* > > - * Reserve AG metadata blocks. ENOSPC here does not mean there was a > > - * growfs failure, just that there still isn't space for new user data > > - * after the grow has been run. > > - */ > > - error = xfs_fs_reserve_ag_blocks(mp); > > - if (error == -ENOSPC) > > - error = 0; > > return error; > > > > out_trans_cancel: > > diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c > > index 44f72c09c203..d047f5f26cc0 100644 > > --- a/fs/xfs/xfs_trans.c > > +++ b/fs/xfs/xfs_trans.c > > @@ -434,7 +434,6 @@ xfs_trans_mod_sb( > > tp->t_res_frextents_delta += delta; > > break; > > case XFS_TRANS_SB_DBLOCKS: > > - ASSERT(delta > 0); > > tp->t_dblocks_delta += delta; > > break; > > case XFS_TRANS_SB_AGCOUNT: > > -- > > 2.27.0 > > >
On Mon, Mar 22, 2021 at 08:07:22PM +0800, Gao Xiang wrote: > On Mon, Mar 22, 2021 at 07:30:40AM -0400, Brian Foster wrote: > > On Fri, Mar 05, 2021 at 10:57:02AM +0800, Gao Xiang wrote: > > > As the first step of shrinking, this attempts to enable shrinking > > > unused space in the last allocation group by fixing up freespace > > > btree, agi, agf and adjusting super block and use a helper > > > xfs_ag_shrink_space() to fixup the last AG. > > > > > > This can be all done in one transaction for now, so I think no > > > additional protection is needed. > > > > > > Reviewed-by: Darrick J. Wong <djwong@kernel.org> > > > Signed-off-by: Gao Xiang <hsiangkao@redhat.com> > > > --- > > > fs/xfs/xfs_fsops.c | 88 ++++++++++++++++++++++++++++------------------ > > > fs/xfs/xfs_trans.c | 1 - > > > 2 files changed, 53 insertions(+), 36 deletions(-) > > > > > > diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c > > > index fc9e799b2ae3..71cba61a451c 100644 > > > --- a/fs/xfs/xfs_fsops.c > > > +++ b/fs/xfs/xfs_fsops.c ... > > > @@ -115,10 +120,15 @@ xfs_growfs_data_private( > > > if (nb_mod && nb_mod < XFS_MIN_AG_BLOCKS) { > > > nagcount--; > > > nb = (xfs_rfsblock_t)nagcount * mp->m_sb.sb_agblocks; > > > - if (nb < mp->m_sb.sb_dblocks) > > > - return -EINVAL; > > > } > > > delta = nb - mp->m_sb.sb_dblocks; > > > + /* > > > + * XFS doesn't really support single-AG filesystems, so do not > > > + * permit callers to remove the filesystem's second and last AG. > > > + */ > > > + if (delta < 0 && nagcount < 2) > > > + return -EINVAL; > > > + > > > > What if the filesystem is already single AG? Unless I'm missing > > something, we already have a check a bit further down that prevents > > removal of AGs in the first place. > > I think it tends to forbid (return -EINVAL) shrinking the filesystem with > a single AG only? Am I missing something? > My assumption was this check means one can't shrink a filesystem that is already agcount == 1. The comment refers to preventing shrink from causing an agcount == 1 fs. What is the intent? Brian > Thanks, > Gao Xiang > > > > > Otherwise looks reasonable.. > > > > Brian > > > > > oagcount = mp->m_sb.sb_agcount; > > > > > > /* allocate the new per-ag structures */ > > > @@ -126,15 +136,22 @@ xfs_growfs_data_private( > > > error = xfs_initialize_perag(mp, nagcount, &nagimax); > > > if (error) > > > return error; > > > + } else if (nagcount < oagcount) { > > > + /* TODO: shrinking the entire AGs hasn't yet completed */ > > > + return -EINVAL; > > > } > > > > > > error = xfs_trans_alloc(mp, &M_RES(mp)->tr_growdata, > > > - XFS_GROWFS_SPACE_RES(mp), 0, XFS_TRANS_RESERVE, &tp); > > > + (delta > 0 ? XFS_GROWFS_SPACE_RES(mp) : -delta), 0, > > > + XFS_TRANS_RESERVE, &tp); > > > if (error) > > > return error; > > > > > > - error = xfs_resizefs_init_new_ags(tp, &id, oagcount, nagcount, > > > - delta, &lastag_resetagres); > > > + if (delta > 0) > > > + error = xfs_resizefs_init_new_ags(tp, &id, oagcount, nagcount, > > > + delta, &lastag_resetagres); > > > + else > > > + error = xfs_ag_shrink_space(mp, &tp, nagcount - 1, -delta); > > > if (error) > > > goto out_trans_cancel; > > > > > > @@ -145,7 +162,7 @@ xfs_growfs_data_private( > > > */ > > > if (nagcount > oagcount) > > > xfs_trans_mod_sb(tp, XFS_TRANS_SB_AGCOUNT, nagcount - oagcount); > > > - if (delta > 0) > > > + if (delta) > > > xfs_trans_mod_sb(tp, XFS_TRANS_SB_DBLOCKS, delta); > > > if (id.nfree) > > > xfs_trans_mod_sb(tp, XFS_TRANS_SB_FDBLOCKS, id.nfree); > > > @@ -169,28 +186,29 @@ xfs_growfs_data_private( > > > xfs_set_low_space_thresholds(mp); > > > mp->m_alloc_set_aside = xfs_alloc_set_aside(mp); > > > > > > - /* > > > - * If we expanded the last AG, free the per-AG reservation > > > - * so we can reinitialize it with the new size. > > > - */ > > > - if (lastag_resetagres) { > > > - struct xfs_perag *pag; > > > - > > > - pag = xfs_perag_get(mp, id.agno); > > > - error = xfs_ag_resv_free(pag); > > > - xfs_perag_put(pag); > > > - if (error) > > > - return error; > > > + if (delta > 0) { > > > + /* > > > + * If we expanded the last AG, free the per-AG reservation > > > + * so we can reinitialize it with the new size. > > > + */ > > > + if (lastag_resetagres) { > > > + struct xfs_perag *pag; > > > + > > > + pag = xfs_perag_get(mp, id.agno); > > > + error = xfs_ag_resv_free(pag); > > > + xfs_perag_put(pag); > > > + if (error) > > > + return error; > > > + } > > > + /* > > > + * Reserve AG metadata blocks. ENOSPC here does not mean there > > > + * was a growfs failure, just that there still isn't space for > > > + * new user data after the grow has been run. > > > + */ > > > + error = xfs_fs_reserve_ag_blocks(mp); > > > + if (error == -ENOSPC) > > > + error = 0; > > > } > > > - > > > - /* > > > - * Reserve AG metadata blocks. ENOSPC here does not mean there was a > > > - * growfs failure, just that there still isn't space for new user data > > > - * after the grow has been run. > > > - */ > > > - error = xfs_fs_reserve_ag_blocks(mp); > > > - if (error == -ENOSPC) > > > - error = 0; > > > return error; > > > > > > out_trans_cancel: > > > diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c > > > index 44f72c09c203..d047f5f26cc0 100644 > > > --- a/fs/xfs/xfs_trans.c > > > +++ b/fs/xfs/xfs_trans.c > > > @@ -434,7 +434,6 @@ xfs_trans_mod_sb( > > > tp->t_res_frextents_delta += delta; > > > break; > > > case XFS_TRANS_SB_DBLOCKS: > > > - ASSERT(delta > 0); > > > tp->t_dblocks_delta += delta; > > > break; > > > case XFS_TRANS_SB_AGCOUNT: > > > -- > > > 2.27.0 > > > > > >
On Mon, Mar 22, 2021 at 08:26:41AM -0400, Brian Foster wrote: > On Mon, Mar 22, 2021 at 08:07:22PM +0800, Gao Xiang wrote: > > On Mon, Mar 22, 2021 at 07:30:40AM -0400, Brian Foster wrote: > > > On Fri, Mar 05, 2021 at 10:57:02AM +0800, Gao Xiang wrote: > > > > As the first step of shrinking, this attempts to enable shrinking > > > > unused space in the last allocation group by fixing up freespace > > > > btree, agi, agf and adjusting super block and use a helper > > > > xfs_ag_shrink_space() to fixup the last AG. > > > > > > > > This can be all done in one transaction for now, so I think no > > > > additional protection is needed. > > > > > > > > Reviewed-by: Darrick J. Wong <djwong@kernel.org> > > > > Signed-off-by: Gao Xiang <hsiangkao@redhat.com> > > > > --- > > > > fs/xfs/xfs_fsops.c | 88 ++++++++++++++++++++++++++++------------------ > > > > fs/xfs/xfs_trans.c | 1 - > > > > 2 files changed, 53 insertions(+), 36 deletions(-) > > > > > > > > diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c > > > > index fc9e799b2ae3..71cba61a451c 100644 > > > > --- a/fs/xfs/xfs_fsops.c > > > > +++ b/fs/xfs/xfs_fsops.c > ... > > > > @@ -115,10 +120,15 @@ xfs_growfs_data_private( > > > > if (nb_mod && nb_mod < XFS_MIN_AG_BLOCKS) { > > > > nagcount--; > > > > nb = (xfs_rfsblock_t)nagcount * mp->m_sb.sb_agblocks; > > > > - if (nb < mp->m_sb.sb_dblocks) > > > > - return -EINVAL; > > > > } > > > > delta = nb - mp->m_sb.sb_dblocks; > > > > + /* > > > > + * XFS doesn't really support single-AG filesystems, so do not > > > > + * permit callers to remove the filesystem's second and last AG. > > > > + */ > > > > + if (delta < 0 && nagcount < 2) > > > > + return -EINVAL; > > > > + > > > > > > What if the filesystem is already single AG? Unless I'm missing > > > something, we already have a check a bit further down that prevents > > > removal of AGs in the first place. > > > > I think it tends to forbid (return -EINVAL) shrinking the filesystem with > > a single AG only? Am I missing something? > > > > My assumption was this check means one can't shrink a filesystem that is > already agcount == 1. The comment refers to preventing shrink from > causing an agcount == 1 fs. What is the intent? I think it means the latter -- preventing shrink from causing an agcount == 1 fs. since nagcount (new agcount) <= 1? Actually, I'm not good at English, if comments need to be improved, please kindly point out. Thank you very much! Thanks, Gao Xiang > > Brian > > > Thanks, > > Gao Xiang > > > > > > > > Otherwise looks reasonable.. > > > > > > Brian > > > > > > > oagcount = mp->m_sb.sb_agcount; > > > > > > > > /* allocate the new per-ag structures */ > > > > @@ -126,15 +136,22 @@ xfs_growfs_data_private( > > > > error = xfs_initialize_perag(mp, nagcount, &nagimax); > > > > if (error) > > > > return error; > > > > + } else if (nagcount < oagcount) { > > > > + /* TODO: shrinking the entire AGs hasn't yet completed */ > > > > + return -EINVAL; > > > > } > > > > > > > > error = xfs_trans_alloc(mp, &M_RES(mp)->tr_growdata, > > > > - XFS_GROWFS_SPACE_RES(mp), 0, XFS_TRANS_RESERVE, &tp); > > > > + (delta > 0 ? XFS_GROWFS_SPACE_RES(mp) : -delta), 0, > > > > + XFS_TRANS_RESERVE, &tp); > > > > if (error) > > > > return error; > > > > > > > > - error = xfs_resizefs_init_new_ags(tp, &id, oagcount, nagcount, > > > > - delta, &lastag_resetagres); > > > > + if (delta > 0) > > > > + error = xfs_resizefs_init_new_ags(tp, &id, oagcount, nagcount, > > > > + delta, &lastag_resetagres); > > > > + else > > > > + error = xfs_ag_shrink_space(mp, &tp, nagcount - 1, -delta); > > > > if (error) > > > > goto out_trans_cancel; > > > > > > > > @@ -145,7 +162,7 @@ xfs_growfs_data_private( > > > > */ > > > > if (nagcount > oagcount) > > > > xfs_trans_mod_sb(tp, XFS_TRANS_SB_AGCOUNT, nagcount - oagcount); > > > > - if (delta > 0) > > > > + if (delta) > > > > xfs_trans_mod_sb(tp, XFS_TRANS_SB_DBLOCKS, delta); > > > > if (id.nfree) > > > > xfs_trans_mod_sb(tp, XFS_TRANS_SB_FDBLOCKS, id.nfree); > > > > @@ -169,28 +186,29 @@ xfs_growfs_data_private( > > > > xfs_set_low_space_thresholds(mp); > > > > mp->m_alloc_set_aside = xfs_alloc_set_aside(mp); > > > > > > > > - /* > > > > - * If we expanded the last AG, free the per-AG reservation > > > > - * so we can reinitialize it with the new size. > > > > - */ > > > > - if (lastag_resetagres) { > > > > - struct xfs_perag *pag; > > > > - > > > > - pag = xfs_perag_get(mp, id.agno); > > > > - error = xfs_ag_resv_free(pag); > > > > - xfs_perag_put(pag); > > > > - if (error) > > > > - return error; > > > > + if (delta > 0) { > > > > + /* > > > > + * If we expanded the last AG, free the per-AG reservation > > > > + * so we can reinitialize it with the new size. > > > > + */ > > > > + if (lastag_resetagres) { > > > > + struct xfs_perag *pag; > > > > + > > > > + pag = xfs_perag_get(mp, id.agno); > > > > + error = xfs_ag_resv_free(pag); > > > > + xfs_perag_put(pag); > > > > + if (error) > > > > + return error; > > > > + } > > > > + /* > > > > + * Reserve AG metadata blocks. ENOSPC here does not mean there > > > > + * was a growfs failure, just that there still isn't space for > > > > + * new user data after the grow has been run. > > > > + */ > > > > + error = xfs_fs_reserve_ag_blocks(mp); > > > > + if (error == -ENOSPC) > > > > + error = 0; > > > > } > > > > - > > > > - /* > > > > - * Reserve AG metadata blocks. ENOSPC here does not mean there was a > > > > - * growfs failure, just that there still isn't space for new user data > > > > - * after the grow has been run. > > > > - */ > > > > - error = xfs_fs_reserve_ag_blocks(mp); > > > > - if (error == -ENOSPC) > > > > - error = 0; > > > > return error; > > > > > > > > out_trans_cancel: > > > > diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c > > > > index 44f72c09c203..d047f5f26cc0 100644 > > > > --- a/fs/xfs/xfs_trans.c > > > > +++ b/fs/xfs/xfs_trans.c > > > > @@ -434,7 +434,6 @@ xfs_trans_mod_sb( > > > > tp->t_res_frextents_delta += delta; > > > > break; > > > > case XFS_TRANS_SB_DBLOCKS: > > > > - ASSERT(delta > 0); > > > > tp->t_dblocks_delta += delta; > > > > break; > > > > case XFS_TRANS_SB_AGCOUNT: > > > > -- > > > > 2.27.0 > > > > > > > > > >
On Mon, Mar 22, 2021 at 08:36:52PM +0800, Gao Xiang wrote: > On Mon, Mar 22, 2021 at 08:26:41AM -0400, Brian Foster wrote: > > On Mon, Mar 22, 2021 at 08:07:22PM +0800, Gao Xiang wrote: > > > On Mon, Mar 22, 2021 at 07:30:40AM -0400, Brian Foster wrote: > > > > On Fri, Mar 05, 2021 at 10:57:02AM +0800, Gao Xiang wrote: > > > > > As the first step of shrinking, this attempts to enable shrinking > > > > > unused space in the last allocation group by fixing up freespace > > > > > btree, agi, agf and adjusting super block and use a helper > > > > > xfs_ag_shrink_space() to fixup the last AG. > > > > > > > > > > This can be all done in one transaction for now, so I think no > > > > > additional protection is needed. > > > > > > > > > > Reviewed-by: Darrick J. Wong <djwong@kernel.org> > > > > > Signed-off-by: Gao Xiang <hsiangkao@redhat.com> > > > > > --- > > > > > fs/xfs/xfs_fsops.c | 88 ++++++++++++++++++++++++++++------------------ > > > > > fs/xfs/xfs_trans.c | 1 - > > > > > 2 files changed, 53 insertions(+), 36 deletions(-) > > > > > > > > > > diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c > > > > > index fc9e799b2ae3..71cba61a451c 100644 > > > > > --- a/fs/xfs/xfs_fsops.c > > > > > +++ b/fs/xfs/xfs_fsops.c > > ... > > > > > @@ -115,10 +120,15 @@ xfs_growfs_data_private( > > > > > if (nb_mod && nb_mod < XFS_MIN_AG_BLOCKS) { > > > > > nagcount--; > > > > > nb = (xfs_rfsblock_t)nagcount * mp->m_sb.sb_agblocks; > > > > > - if (nb < mp->m_sb.sb_dblocks) > > > > > - return -EINVAL; > > > > > } > > > > > delta = nb - mp->m_sb.sb_dblocks; > > > > > + /* > > > > > + * XFS doesn't really support single-AG filesystems, so do not > > > > > + * permit callers to remove the filesystem's second and last AG. > > > > > + */ > > > > > + if (delta < 0 && nagcount < 2) > > > > > + return -EINVAL; > > > > > + > > > > > > > > What if the filesystem is already single AG? Unless I'm missing > > > > something, we already have a check a bit further down that prevents > > > > removal of AGs in the first place. > > > > > > I think it tends to forbid (return -EINVAL) shrinking the filesystem with > > > a single AG only? Am I missing something? > > > > > > > My assumption was this check means one can't shrink a filesystem that is > > already agcount == 1. The comment refers to preventing shrink from > > causing an agcount == 1 fs. What is the intent? > > I think it means the latter -- preventing shrink from causing an agcount == 1 > fs. since nagcount (new agcount) <= 1? > Right, so that leads to my question... does this check also fail a shrink on an fs that is already agcount == 1? If so, why? I know technically it's not a supported configuration, but mkfs allows it. Brian > Actually, I'm not good at English, if comments need to be improved, please > kindly point out. Thank you very much! > > Thanks, > Gao Xiang > > > > > Brian > > > > > Thanks, > > > Gao Xiang > > > > > > > > > > > Otherwise looks reasonable.. > > > > > > > > Brian > > > > > > > > > oagcount = mp->m_sb.sb_agcount; > > > > > > > > > > /* allocate the new per-ag structures */ > > > > > @@ -126,15 +136,22 @@ xfs_growfs_data_private( > > > > > error = xfs_initialize_perag(mp, nagcount, &nagimax); > > > > > if (error) > > > > > return error; > > > > > + } else if (nagcount < oagcount) { > > > > > + /* TODO: shrinking the entire AGs hasn't yet completed */ > > > > > + return -EINVAL; > > > > > } > > > > > > > > > > error = xfs_trans_alloc(mp, &M_RES(mp)->tr_growdata, > > > > > - XFS_GROWFS_SPACE_RES(mp), 0, XFS_TRANS_RESERVE, &tp); > > > > > + (delta > 0 ? XFS_GROWFS_SPACE_RES(mp) : -delta), 0, > > > > > + XFS_TRANS_RESERVE, &tp); > > > > > if (error) > > > > > return error; > > > > > > > > > > - error = xfs_resizefs_init_new_ags(tp, &id, oagcount, nagcount, > > > > > - delta, &lastag_resetagres); > > > > > + if (delta > 0) > > > > > + error = xfs_resizefs_init_new_ags(tp, &id, oagcount, nagcount, > > > > > + delta, &lastag_resetagres); > > > > > + else > > > > > + error = xfs_ag_shrink_space(mp, &tp, nagcount - 1, -delta); > > > > > if (error) > > > > > goto out_trans_cancel; > > > > > > > > > > @@ -145,7 +162,7 @@ xfs_growfs_data_private( > > > > > */ > > > > > if (nagcount > oagcount) > > > > > xfs_trans_mod_sb(tp, XFS_TRANS_SB_AGCOUNT, nagcount - oagcount); > > > > > - if (delta > 0) > > > > > + if (delta) > > > > > xfs_trans_mod_sb(tp, XFS_TRANS_SB_DBLOCKS, delta); > > > > > if (id.nfree) > > > > > xfs_trans_mod_sb(tp, XFS_TRANS_SB_FDBLOCKS, id.nfree); > > > > > @@ -169,28 +186,29 @@ xfs_growfs_data_private( > > > > > xfs_set_low_space_thresholds(mp); > > > > > mp->m_alloc_set_aside = xfs_alloc_set_aside(mp); > > > > > > > > > > - /* > > > > > - * If we expanded the last AG, free the per-AG reservation > > > > > - * so we can reinitialize it with the new size. > > > > > - */ > > > > > - if (lastag_resetagres) { > > > > > - struct xfs_perag *pag; > > > > > - > > > > > - pag = xfs_perag_get(mp, id.agno); > > > > > - error = xfs_ag_resv_free(pag); > > > > > - xfs_perag_put(pag); > > > > > - if (error) > > > > > - return error; > > > > > + if (delta > 0) { > > > > > + /* > > > > > + * If we expanded the last AG, free the per-AG reservation > > > > > + * so we can reinitialize it with the new size. > > > > > + */ > > > > > + if (lastag_resetagres) { > > > > > + struct xfs_perag *pag; > > > > > + > > > > > + pag = xfs_perag_get(mp, id.agno); > > > > > + error = xfs_ag_resv_free(pag); > > > > > + xfs_perag_put(pag); > > > > > + if (error) > > > > > + return error; > > > > > + } > > > > > + /* > > > > > + * Reserve AG metadata blocks. ENOSPC here does not mean there > > > > > + * was a growfs failure, just that there still isn't space for > > > > > + * new user data after the grow has been run. > > > > > + */ > > > > > + error = xfs_fs_reserve_ag_blocks(mp); > > > > > + if (error == -ENOSPC) > > > > > + error = 0; > > > > > } > > > > > - > > > > > - /* > > > > > - * Reserve AG metadata blocks. ENOSPC here does not mean there was a > > > > > - * growfs failure, just that there still isn't space for new user data > > > > > - * after the grow has been run. > > > > > - */ > > > > > - error = xfs_fs_reserve_ag_blocks(mp); > > > > > - if (error == -ENOSPC) > > > > > - error = 0; > > > > > return error; > > > > > > > > > > out_trans_cancel: > > > > > diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c > > > > > index 44f72c09c203..d047f5f26cc0 100644 > > > > > --- a/fs/xfs/xfs_trans.c > > > > > +++ b/fs/xfs/xfs_trans.c > > > > > @@ -434,7 +434,6 @@ xfs_trans_mod_sb( > > > > > tp->t_res_frextents_delta += delta; > > > > > break; > > > > > case XFS_TRANS_SB_DBLOCKS: > > > > > - ASSERT(delta > 0); > > > > > tp->t_dblocks_delta += delta; > > > > > break; > > > > > case XFS_TRANS_SB_AGCOUNT: > > > > > -- > > > > > 2.27.0 > > > > > > > > > > > > > > >
On Mon, Mar 22, 2021 at 08:43:19AM -0400, Brian Foster wrote: > On Mon, Mar 22, 2021 at 08:36:52PM +0800, Gao Xiang wrote: > > On Mon, Mar 22, 2021 at 08:26:41AM -0400, Brian Foster wrote: > > > On Mon, Mar 22, 2021 at 08:07:22PM +0800, Gao Xiang wrote: > > > > On Mon, Mar 22, 2021 at 07:30:40AM -0400, Brian Foster wrote: > > > > > On Fri, Mar 05, 2021 at 10:57:02AM +0800, Gao Xiang wrote: > > > > > > As the first step of shrinking, this attempts to enable shrinking > > > > > > unused space in the last allocation group by fixing up freespace > > > > > > btree, agi, agf and adjusting super block and use a helper > > > > > > xfs_ag_shrink_space() to fixup the last AG. > > > > > > > > > > > > This can be all done in one transaction for now, so I think no > > > > > > additional protection is needed. > > > > > > > > > > > > Reviewed-by: Darrick J. Wong <djwong@kernel.org> > > > > > > Signed-off-by: Gao Xiang <hsiangkao@redhat.com> > > > > > > --- > > > > > > fs/xfs/xfs_fsops.c | 88 ++++++++++++++++++++++++++++------------------ > > > > > > fs/xfs/xfs_trans.c | 1 - > > > > > > 2 files changed, 53 insertions(+), 36 deletions(-) > > > > > > > > > > > > diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c > > > > > > index fc9e799b2ae3..71cba61a451c 100644 > > > > > > --- a/fs/xfs/xfs_fsops.c > > > > > > +++ b/fs/xfs/xfs_fsops.c > > > ... > > > > > > @@ -115,10 +120,15 @@ xfs_growfs_data_private( > > > > > > if (nb_mod && nb_mod < XFS_MIN_AG_BLOCKS) { > > > > > > nagcount--; > > > > > > nb = (xfs_rfsblock_t)nagcount * mp->m_sb.sb_agblocks; > > > > > > - if (nb < mp->m_sb.sb_dblocks) > > > > > > - return -EINVAL; > > > > > > } > > > > > > delta = nb - mp->m_sb.sb_dblocks; > > > > > > + /* > > > > > > + * XFS doesn't really support single-AG filesystems, so do not > > > > > > + * permit callers to remove the filesystem's second and last AG. > > > > > > + */ > > > > > > + if (delta < 0 && nagcount < 2) > > > > > > + return -EINVAL; > > > > > > + > > > > > > > > > > What if the filesystem is already single AG? Unless I'm missing > > > > > something, we already have a check a bit further down that prevents > > > > > removal of AGs in the first place. > > > > > > > > I think it tends to forbid (return -EINVAL) shrinking the filesystem with > > > > a single AG only? Am I missing something? > > > > > > > > > > My assumption was this check means one can't shrink a filesystem that is > > > already agcount == 1. The comment refers to preventing shrink from > > > causing an agcount == 1 fs. What is the intent? > > > > I think it means the latter -- preventing shrink from causing an agcount == 1 > > fs. since nagcount (new agcount) <= 1? > > > > Right, so that leads to my question... does this check also fail a > shrink on an fs that is already agcount == 1? If so, why? I know > technically it's not a supported configuration, but mkfs allows it. Ah, I'm not sure if Darrick would like to forbid agcount == 1 shrinking functionitity completely, see the previous comment: https://lore.kernel.org/r/20201014160633.GD9832@magnolia/ (please ignore the modification at that time, since it was buggy...) Thanks, Gao Xiang > > Brian > > > Actually, I'm not good at English, if comments need to be improved, please > > kindly point out. Thank you very much! > > > > Thanks, > > Gao Xiang > > > > > > > > Brian > > > > > > > Thanks, > > > > Gao Xiang > > > > > > > > > > > > > > Otherwise looks reasonable.. > > > > > > > > > > Brian > > > > > > > > > > > oagcount = mp->m_sb.sb_agcount; > > > > > > > > > > > > /* allocate the new per-ag structures */ > > > > > > @@ -126,15 +136,22 @@ xfs_growfs_data_private( > > > > > > error = xfs_initialize_perag(mp, nagcount, &nagimax); > > > > > > if (error) > > > > > > return error; > > > > > > + } else if (nagcount < oagcount) { > > > > > > + /* TODO: shrinking the entire AGs hasn't yet completed */ > > > > > > + return -EINVAL; > > > > > > } > > > > > > > > > > > > error = xfs_trans_alloc(mp, &M_RES(mp)->tr_growdata, > > > > > > - XFS_GROWFS_SPACE_RES(mp), 0, XFS_TRANS_RESERVE, &tp); > > > > > > + (delta > 0 ? XFS_GROWFS_SPACE_RES(mp) : -delta), 0, > > > > > > + XFS_TRANS_RESERVE, &tp); > > > > > > if (error) > > > > > > return error; > > > > > > > > > > > > - error = xfs_resizefs_init_new_ags(tp, &id, oagcount, nagcount, > > > > > > - delta, &lastag_resetagres); > > > > > > + if (delta > 0) > > > > > > + error = xfs_resizefs_init_new_ags(tp, &id, oagcount, nagcount, > > > > > > + delta, &lastag_resetagres); > > > > > > + else > > > > > > + error = xfs_ag_shrink_space(mp, &tp, nagcount - 1, -delta); > > > > > > if (error) > > > > > > goto out_trans_cancel; > > > > > > > > > > > > @@ -145,7 +162,7 @@ xfs_growfs_data_private( > > > > > > */ > > > > > > if (nagcount > oagcount) > > > > > > xfs_trans_mod_sb(tp, XFS_TRANS_SB_AGCOUNT, nagcount - oagcount); > > > > > > - if (delta > 0) > > > > > > + if (delta) > > > > > > xfs_trans_mod_sb(tp, XFS_TRANS_SB_DBLOCKS, delta); > > > > > > if (id.nfree) > > > > > > xfs_trans_mod_sb(tp, XFS_TRANS_SB_FDBLOCKS, id.nfree); > > > > > > @@ -169,28 +186,29 @@ xfs_growfs_data_private( > > > > > > xfs_set_low_space_thresholds(mp); > > > > > > mp->m_alloc_set_aside = xfs_alloc_set_aside(mp); > > > > > > > > > > > > - /* > > > > > > - * If we expanded the last AG, free the per-AG reservation > > > > > > - * so we can reinitialize it with the new size. > > > > > > - */ > > > > > > - if (lastag_resetagres) { > > > > > > - struct xfs_perag *pag; > > > > > > - > > > > > > - pag = xfs_perag_get(mp, id.agno); > > > > > > - error = xfs_ag_resv_free(pag); > > > > > > - xfs_perag_put(pag); > > > > > > - if (error) > > > > > > - return error; > > > > > > + if (delta > 0) { > > > > > > + /* > > > > > > + * If we expanded the last AG, free the per-AG reservation > > > > > > + * so we can reinitialize it with the new size. > > > > > > + */ > > > > > > + if (lastag_resetagres) { > > > > > > + struct xfs_perag *pag; > > > > > > + > > > > > > + pag = xfs_perag_get(mp, id.agno); > > > > > > + error = xfs_ag_resv_free(pag); > > > > > > + xfs_perag_put(pag); > > > > > > + if (error) > > > > > > + return error; > > > > > > + } > > > > > > + /* > > > > > > + * Reserve AG metadata blocks. ENOSPC here does not mean there > > > > > > + * was a growfs failure, just that there still isn't space for > > > > > > + * new user data after the grow has been run. > > > > > > + */ > > > > > > + error = xfs_fs_reserve_ag_blocks(mp); > > > > > > + if (error == -ENOSPC) > > > > > > + error = 0; > > > > > > } > > > > > > - > > > > > > - /* > > > > > > - * Reserve AG metadata blocks. ENOSPC here does not mean there was a > > > > > > - * growfs failure, just that there still isn't space for new user data > > > > > > - * after the grow has been run. > > > > > > - */ > > > > > > - error = xfs_fs_reserve_ag_blocks(mp); > > > > > > - if (error == -ENOSPC) > > > > > > - error = 0; > > > > > > return error; > > > > > > > > > > > > out_trans_cancel: > > > > > > diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c > > > > > > index 44f72c09c203..d047f5f26cc0 100644 > > > > > > --- a/fs/xfs/xfs_trans.c > > > > > > +++ b/fs/xfs/xfs_trans.c > > > > > > @@ -434,7 +434,6 @@ xfs_trans_mod_sb( > > > > > > tp->t_res_frextents_delta += delta; > > > > > > break; > > > > > > case XFS_TRANS_SB_DBLOCKS: > > > > > > - ASSERT(delta > 0); > > > > > > tp->t_dblocks_delta += delta; > > > > > > break; > > > > > > case XFS_TRANS_SB_AGCOUNT: > > > > > > -- > > > > > > 2.27.0 > > > > > > > > > > > > > > > > > > > > >
On Mon, Mar 22, 2021 at 08:50:28PM +0800, Gao Xiang wrote: > On Mon, Mar 22, 2021 at 08:43:19AM -0400, Brian Foster wrote: > > On Mon, Mar 22, 2021 at 08:36:52PM +0800, Gao Xiang wrote: > > > On Mon, Mar 22, 2021 at 08:26:41AM -0400, Brian Foster wrote: > > > > On Mon, Mar 22, 2021 at 08:07:22PM +0800, Gao Xiang wrote: > > > > > On Mon, Mar 22, 2021 at 07:30:40AM -0400, Brian Foster wrote: > > > > > > On Fri, Mar 05, 2021 at 10:57:02AM +0800, Gao Xiang wrote: > > > > > > > As the first step of shrinking, this attempts to enable shrinking > > > > > > > unused space in the last allocation group by fixing up freespace > > > > > > > btree, agi, agf and adjusting super block and use a helper > > > > > > > xfs_ag_shrink_space() to fixup the last AG. > > > > > > > > > > > > > > This can be all done in one transaction for now, so I think no > > > > > > > additional protection is needed. > > > > > > > > > > > > > > Reviewed-by: Darrick J. Wong <djwong@kernel.org> > > > > > > > Signed-off-by: Gao Xiang <hsiangkao@redhat.com> > > > > > > > --- > > > > > > > fs/xfs/xfs_fsops.c | 88 ++++++++++++++++++++++++++++------------------ > > > > > > > fs/xfs/xfs_trans.c | 1 - > > > > > > > 2 files changed, 53 insertions(+), 36 deletions(-) > > > > > > > > > > > > > > diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c > > > > > > > index fc9e799b2ae3..71cba61a451c 100644 > > > > > > > --- a/fs/xfs/xfs_fsops.c > > > > > > > +++ b/fs/xfs/xfs_fsops.c > > > > ... > > > > > > > @@ -115,10 +120,15 @@ xfs_growfs_data_private( > > > > > > > if (nb_mod && nb_mod < XFS_MIN_AG_BLOCKS) { > > > > > > > nagcount--; > > > > > > > nb = (xfs_rfsblock_t)nagcount * mp->m_sb.sb_agblocks; > > > > > > > - if (nb < mp->m_sb.sb_dblocks) > > > > > > > - return -EINVAL; > > > > > > > } > > > > > > > delta = nb - mp->m_sb.sb_dblocks; > > > > > > > + /* > > > > > > > + * XFS doesn't really support single-AG filesystems, so do not > > > > > > > + * permit callers to remove the filesystem's second and last AG. > > > > > > > + */ > > > > > > > + if (delta < 0 && nagcount < 2) > > > > > > > + return -EINVAL; > > > > > > > + > > > > > > > > > > > > What if the filesystem is already single AG? Unless I'm missing > > > > > > something, we already have a check a bit further down that prevents > > > > > > removal of AGs in the first place. > > > > > > > > > > I think it tends to forbid (return -EINVAL) shrinking the filesystem with > > > > > a single AG only? Am I missing something? > > > > > > > > > > > > > My assumption was this check means one can't shrink a filesystem that is > > > > already agcount == 1. The comment refers to preventing shrink from > > > > causing an agcount == 1 fs. What is the intent? Both of those things. > > > > > > I think it means the latter -- preventing shrink from causing an agcount == 1 > > > fs. since nagcount (new agcount) <= 1? > > > > > > > Right, so that leads to my question... does this check also fail a > > shrink on an fs that is already agcount == 1? If so, why? I know > > technically it's not a supported configuration, but mkfs allows it. > > Ah, I'm not sure if Darrick would like to forbid agcount == 1 shrinking > functionitity completely, see the previous comment: > https://lore.kernel.org/r/20201014160633.GD9832@magnolia/ > > (please ignore the modification at that time, since it was buggy...) Given the confusion I propose a new comment: /* * Reject filesystems with a single AG because they are not * supported, and reject a shrink operation that would cause a * filesystem to become unsupported. */ if (delta < 0 && nagcount < 2) return -EINVAL; --D > > Thanks, > Gao Xiang > > > > > Brian > > > > > Actually, I'm not good at English, if comments need to be improved, please > > > kindly point out. Thank you very much! > > > > > > Thanks, > > > Gao Xiang > > > > > > > > > > > Brian > > > > > > > > > Thanks, > > > > > Gao Xiang > > > > > > > > > > > > > > > > > Otherwise looks reasonable.. > > > > > > > > > > > > Brian > > > > > > > > > > > > > oagcount = mp->m_sb.sb_agcount; > > > > > > > > > > > > > > /* allocate the new per-ag structures */ > > > > > > > @@ -126,15 +136,22 @@ xfs_growfs_data_private( > > > > > > > error = xfs_initialize_perag(mp, nagcount, &nagimax); > > > > > > > if (error) > > > > > > > return error; > > > > > > > + } else if (nagcount < oagcount) { > > > > > > > + /* TODO: shrinking the entire AGs hasn't yet completed */ > > > > > > > + return -EINVAL; > > > > > > > } > > > > > > > > > > > > > > error = xfs_trans_alloc(mp, &M_RES(mp)->tr_growdata, > > > > > > > - XFS_GROWFS_SPACE_RES(mp), 0, XFS_TRANS_RESERVE, &tp); > > > > > > > + (delta > 0 ? XFS_GROWFS_SPACE_RES(mp) : -delta), 0, > > > > > > > + XFS_TRANS_RESERVE, &tp); > > > > > > > if (error) > > > > > > > return error; > > > > > > > > > > > > > > - error = xfs_resizefs_init_new_ags(tp, &id, oagcount, nagcount, > > > > > > > - delta, &lastag_resetagres); > > > > > > > + if (delta > 0) > > > > > > > + error = xfs_resizefs_init_new_ags(tp, &id, oagcount, nagcount, > > > > > > > + delta, &lastag_resetagres); > > > > > > > + else > > > > > > > + error = xfs_ag_shrink_space(mp, &tp, nagcount - 1, -delta); > > > > > > > if (error) > > > > > > > goto out_trans_cancel; > > > > > > > > > > > > > > @@ -145,7 +162,7 @@ xfs_growfs_data_private( > > > > > > > */ > > > > > > > if (nagcount > oagcount) > > > > > > > xfs_trans_mod_sb(tp, XFS_TRANS_SB_AGCOUNT, nagcount - oagcount); > > > > > > > - if (delta > 0) > > > > > > > + if (delta) > > > > > > > xfs_trans_mod_sb(tp, XFS_TRANS_SB_DBLOCKS, delta); > > > > > > > if (id.nfree) > > > > > > > xfs_trans_mod_sb(tp, XFS_TRANS_SB_FDBLOCKS, id.nfree); > > > > > > > @@ -169,28 +186,29 @@ xfs_growfs_data_private( > > > > > > > xfs_set_low_space_thresholds(mp); > > > > > > > mp->m_alloc_set_aside = xfs_alloc_set_aside(mp); > > > > > > > > > > > > > > - /* > > > > > > > - * If we expanded the last AG, free the per-AG reservation > > > > > > > - * so we can reinitialize it with the new size. > > > > > > > - */ > > > > > > > - if (lastag_resetagres) { > > > > > > > - struct xfs_perag *pag; > > > > > > > - > > > > > > > - pag = xfs_perag_get(mp, id.agno); > > > > > > > - error = xfs_ag_resv_free(pag); > > > > > > > - xfs_perag_put(pag); > > > > > > > - if (error) > > > > > > > - return error; > > > > > > > + if (delta > 0) { > > > > > > > + /* > > > > > > > + * If we expanded the last AG, free the per-AG reservation > > > > > > > + * so we can reinitialize it with the new size. > > > > > > > + */ > > > > > > > + if (lastag_resetagres) { > > > > > > > + struct xfs_perag *pag; > > > > > > > + > > > > > > > + pag = xfs_perag_get(mp, id.agno); > > > > > > > + error = xfs_ag_resv_free(pag); > > > > > > > + xfs_perag_put(pag); > > > > > > > + if (error) > > > > > > > + return error; > > > > > > > + } > > > > > > > + /* > > > > > > > + * Reserve AG metadata blocks. ENOSPC here does not mean there > > > > > > > + * was a growfs failure, just that there still isn't space for > > > > > > > + * new user data after the grow has been run. > > > > > > > + */ > > > > > > > + error = xfs_fs_reserve_ag_blocks(mp); > > > > > > > + if (error == -ENOSPC) > > > > > > > + error = 0; > > > > > > > } > > > > > > > - > > > > > > > - /* > > > > > > > - * Reserve AG metadata blocks. ENOSPC here does not mean there was a > > > > > > > - * growfs failure, just that there still isn't space for new user data > > > > > > > - * after the grow has been run. > > > > > > > - */ > > > > > > > - error = xfs_fs_reserve_ag_blocks(mp); > > > > > > > - if (error == -ENOSPC) > > > > > > > - error = 0; > > > > > > > return error; > > > > > > > > > > > > > > out_trans_cancel: > > > > > > > diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c > > > > > > > index 44f72c09c203..d047f5f26cc0 100644 > > > > > > > --- a/fs/xfs/xfs_trans.c > > > > > > > +++ b/fs/xfs/xfs_trans.c > > > > > > > @@ -434,7 +434,6 @@ xfs_trans_mod_sb( > > > > > > > tp->t_res_frextents_delta += delta; > > > > > > > break; > > > > > > > case XFS_TRANS_SB_DBLOCKS: > > > > > > > - ASSERT(delta > 0); > > > > > > > tp->t_dblocks_delta += delta; > > > > > > > break; > > > > > > > case XFS_TRANS_SB_AGCOUNT: > > > > > > > -- > > > > > > > 2.27.0 > > > > > > > > > > > > > > > > > > > > > > > > > > > >
On Mon, Mar 22, 2021 at 09:42:55AM -0700, Darrick J. Wong wrote: > On Mon, Mar 22, 2021 at 08:50:28PM +0800, Gao Xiang wrote: > > On Mon, Mar 22, 2021 at 08:43:19AM -0400, Brian Foster wrote: > > > On Mon, Mar 22, 2021 at 08:36:52PM +0800, Gao Xiang wrote: > > > > On Mon, Mar 22, 2021 at 08:26:41AM -0400, Brian Foster wrote: > > > > > On Mon, Mar 22, 2021 at 08:07:22PM +0800, Gao Xiang wrote: > > > > > > On Mon, Mar 22, 2021 at 07:30:40AM -0400, Brian Foster wrote: > > > > > > > On Fri, Mar 05, 2021 at 10:57:02AM +0800, Gao Xiang wrote: > > > > > > > > As the first step of shrinking, this attempts to enable shrinking > > > > > > > > unused space in the last allocation group by fixing up freespace > > > > > > > > btree, agi, agf and adjusting super block and use a helper > > > > > > > > xfs_ag_shrink_space() to fixup the last AG. > > > > > > > > > > > > > > > > This can be all done in one transaction for now, so I think no > > > > > > > > additional protection is needed. > > > > > > > > > > > > > > > > Reviewed-by: Darrick J. Wong <djwong@kernel.org> > > > > > > > > Signed-off-by: Gao Xiang <hsiangkao@redhat.com> > > > > > > > > --- > > > > > > > > fs/xfs/xfs_fsops.c | 88 ++++++++++++++++++++++++++++------------------ > > > > > > > > fs/xfs/xfs_trans.c | 1 - > > > > > > > > 2 files changed, 53 insertions(+), 36 deletions(-) > > > > > > > > > > > > > > > > diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c > > > > > > > > index fc9e799b2ae3..71cba61a451c 100644 > > > > > > > > --- a/fs/xfs/xfs_fsops.c > > > > > > > > +++ b/fs/xfs/xfs_fsops.c > > > > > ... > > > > > > > > @@ -115,10 +120,15 @@ xfs_growfs_data_private( > > > > > > > > if (nb_mod && nb_mod < XFS_MIN_AG_BLOCKS) { > > > > > > > > nagcount--; > > > > > > > > nb = (xfs_rfsblock_t)nagcount * mp->m_sb.sb_agblocks; > > > > > > > > - if (nb < mp->m_sb.sb_dblocks) > > > > > > > > - return -EINVAL; > > > > > > > > } > > > > > > > > delta = nb - mp->m_sb.sb_dblocks; > > > > > > > > + /* > > > > > > > > + * XFS doesn't really support single-AG filesystems, so do not > > > > > > > > + * permit callers to remove the filesystem's second and last AG. > > > > > > > > + */ > > > > > > > > + if (delta < 0 && nagcount < 2) > > > > > > > > + return -EINVAL; > > > > > > > > + > > > > > > > > > > > > > > What if the filesystem is already single AG? Unless I'm missing > > > > > > > something, we already have a check a bit further down that prevents > > > > > > > removal of AGs in the first place. > > > > > > > > > > > > I think it tends to forbid (return -EINVAL) shrinking the filesystem with > > > > > > a single AG only? Am I missing something? > > > > > > > > > > > > > > > > My assumption was this check means one can't shrink a filesystem that is > > > > > already agcount == 1. The comment refers to preventing shrink from > > > > > causing an agcount == 1 fs. What is the intent? > > Both of those things. > > > > > > > > > I think it means the latter -- preventing shrink from causing an agcount == 1 > > > > fs. since nagcount (new agcount) <= 1? > > > > > > > > > > Right, so that leads to my question... does this check also fail a > > > shrink on an fs that is already agcount == 1? If so, why? I know > > > technically it's not a supported configuration, but mkfs allows it. > > > > Ah, I'm not sure if Darrick would like to forbid agcount == 1 shrinking > > functionitity completely, see the previous comment: > > https://lore.kernel.org/r/20201014160633.GD9832@magnolia/ > > > > (please ignore the modification at that time, since it was buggy...) > > Given the confusion I propose a new comment: > > /* > * Reject filesystems with a single AG because they are not > * supported, and reject a shrink operation that would cause a > * filesystem to become unsupported. > */ > if (delta < 0 && nagcount < 2) > return -EINVAL; > ok, will update this comment. thanks for your suggestion! Thanks, Gao Xiang > --D
diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c index fc9e799b2ae3..71cba61a451c 100644 --- a/fs/xfs/xfs_fsops.c +++ b/fs/xfs/xfs_fsops.c @@ -91,23 +91,28 @@ xfs_growfs_data_private( xfs_agnumber_t nagcount; xfs_agnumber_t nagimax = 0; xfs_rfsblock_t nb, nb_div, nb_mod; - xfs_rfsblock_t delta; + int64_t delta; bool lastag_resetagres; xfs_agnumber_t oagcount; struct xfs_trans *tp; struct aghdr_init_data id = {}; nb = in->newblocks; - if (nb < mp->m_sb.sb_dblocks) - return -EINVAL; - if ((error = xfs_sb_validate_fsb_count(&mp->m_sb, nb))) + if (nb == mp->m_sb.sb_dblocks) + return 0; + + error = xfs_sb_validate_fsb_count(&mp->m_sb, nb); + if (error) return error; - error = xfs_buf_read_uncached(mp->m_ddev_targp, + + if (nb > mp->m_sb.sb_dblocks) { + error = xfs_buf_read_uncached(mp->m_ddev_targp, XFS_FSB_TO_BB(mp, nb) - XFS_FSS_TO_BB(mp, 1), XFS_FSS_TO_BB(mp, 1), 0, &bp, NULL); - if (error) - return error; - xfs_buf_relse(bp); + if (error) + return error; + xfs_buf_relse(bp); + } nb_div = nb; nb_mod = do_div(nb_div, mp->m_sb.sb_agblocks); @@ -115,10 +120,15 @@ xfs_growfs_data_private( if (nb_mod && nb_mod < XFS_MIN_AG_BLOCKS) { nagcount--; nb = (xfs_rfsblock_t)nagcount * mp->m_sb.sb_agblocks; - if (nb < mp->m_sb.sb_dblocks) - return -EINVAL; } delta = nb - mp->m_sb.sb_dblocks; + /* + * XFS doesn't really support single-AG filesystems, so do not + * permit callers to remove the filesystem's second and last AG. + */ + if (delta < 0 && nagcount < 2) + return -EINVAL; + oagcount = mp->m_sb.sb_agcount; /* allocate the new per-ag structures */ @@ -126,15 +136,22 @@ xfs_growfs_data_private( error = xfs_initialize_perag(mp, nagcount, &nagimax); if (error) return error; + } else if (nagcount < oagcount) { + /* TODO: shrinking the entire AGs hasn't yet completed */ + return -EINVAL; } error = xfs_trans_alloc(mp, &M_RES(mp)->tr_growdata, - XFS_GROWFS_SPACE_RES(mp), 0, XFS_TRANS_RESERVE, &tp); + (delta > 0 ? XFS_GROWFS_SPACE_RES(mp) : -delta), 0, + XFS_TRANS_RESERVE, &tp); if (error) return error; - error = xfs_resizefs_init_new_ags(tp, &id, oagcount, nagcount, - delta, &lastag_resetagres); + if (delta > 0) + error = xfs_resizefs_init_new_ags(tp, &id, oagcount, nagcount, + delta, &lastag_resetagres); + else + error = xfs_ag_shrink_space(mp, &tp, nagcount - 1, -delta); if (error) goto out_trans_cancel; @@ -145,7 +162,7 @@ xfs_growfs_data_private( */ if (nagcount > oagcount) xfs_trans_mod_sb(tp, XFS_TRANS_SB_AGCOUNT, nagcount - oagcount); - if (delta > 0) + if (delta) xfs_trans_mod_sb(tp, XFS_TRANS_SB_DBLOCKS, delta); if (id.nfree) xfs_trans_mod_sb(tp, XFS_TRANS_SB_FDBLOCKS, id.nfree); @@ -169,28 +186,29 @@ xfs_growfs_data_private( xfs_set_low_space_thresholds(mp); mp->m_alloc_set_aside = xfs_alloc_set_aside(mp); - /* - * If we expanded the last AG, free the per-AG reservation - * so we can reinitialize it with the new size. - */ - if (lastag_resetagres) { - struct xfs_perag *pag; - - pag = xfs_perag_get(mp, id.agno); - error = xfs_ag_resv_free(pag); - xfs_perag_put(pag); - if (error) - return error; + if (delta > 0) { + /* + * If we expanded the last AG, free the per-AG reservation + * so we can reinitialize it with the new size. + */ + if (lastag_resetagres) { + struct xfs_perag *pag; + + pag = xfs_perag_get(mp, id.agno); + error = xfs_ag_resv_free(pag); + xfs_perag_put(pag); + if (error) + return error; + } + /* + * Reserve AG metadata blocks. ENOSPC here does not mean there + * was a growfs failure, just that there still isn't space for + * new user data after the grow has been run. + */ + error = xfs_fs_reserve_ag_blocks(mp); + if (error == -ENOSPC) + error = 0; } - - /* - * Reserve AG metadata blocks. ENOSPC here does not mean there was a - * growfs failure, just that there still isn't space for new user data - * after the grow has been run. - */ - error = xfs_fs_reserve_ag_blocks(mp); - if (error == -ENOSPC) - error = 0; return error; out_trans_cancel: diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c index 44f72c09c203..d047f5f26cc0 100644 --- a/fs/xfs/xfs_trans.c +++ b/fs/xfs/xfs_trans.c @@ -434,7 +434,6 @@ xfs_trans_mod_sb( tp->t_res_frextents_delta += delta; break; case XFS_TRANS_SB_DBLOCKS: - ASSERT(delta > 0); tp->t_dblocks_delta += delta; break; case XFS_TRANS_SB_AGCOUNT: