| Message ID | 20210305025703.3069469-4-hsiangkao@redhat.com (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
| Series | xfs: support shrinking free space in the last AG | expand |
On Fri, Mar 05, 2021 at 10:57:01AM +0800, Gao Xiang wrote: > This patch introduces a helper to shrink unused space in the last AG > by fixing up the freespace btree. > > Also make sure that the per-AG reservation works under the new AG > size. If such per-AG reservation or extent allocation fails, roll > the transaction so the new transaction could cancel without any side > effects. > > Signed-off-by: Gao Xiang <hsiangkao@redhat.com> Looks fine, moving on to examining the fstests... Reviewed-by: Darrick J. Wong <djwong@kernel.org> --D > --- > fs/xfs/libxfs/xfs_ag.c | 111 +++++++++++++++++++++++++++++++++++++++++ > fs/xfs/libxfs/xfs_ag.h | 4 +- > 2 files changed, 114 insertions(+), 1 deletion(-) > > diff --git a/fs/xfs/libxfs/xfs_ag.c b/fs/xfs/libxfs/xfs_ag.c > index 9331f3516afa..1f6f9e70e1cb 100644 > --- a/fs/xfs/libxfs/xfs_ag.c > +++ b/fs/xfs/libxfs/xfs_ag.c > @@ -22,6 +22,11 @@ > #include "xfs_ag.h" > #include "xfs_ag_resv.h" > #include "xfs_health.h" > +#include "xfs_error.h" > +#include "xfs_bmap.h" > +#include "xfs_defer.h" > +#include "xfs_log_format.h" > +#include "xfs_trans.h" > > static int > xfs_get_aghdr_buf( > @@ -485,6 +490,112 @@ xfs_ag_init_headers( > return error; > } > > +int > +xfs_ag_shrink_space( > + struct xfs_mount *mp, > + struct xfs_trans **tpp, > + xfs_agnumber_t agno, > + xfs_extlen_t delta) > +{ > + struct xfs_alloc_arg args = { > + .tp = *tpp, > + .mp = mp, > + .type = XFS_ALLOCTYPE_THIS_BNO, > + .minlen = delta, > + .maxlen = delta, > + .oinfo = XFS_RMAP_OINFO_SKIP_UPDATE, > + .resv = XFS_AG_RESV_NONE, > + .prod = 1 > + }; > + struct xfs_buf *agibp, *agfbp; > + struct xfs_agi *agi; > + struct xfs_agf *agf; > + int error, err2; > + > + ASSERT(agno == mp->m_sb.sb_agcount - 1); > + error = xfs_ialloc_read_agi(mp, *tpp, agno, &agibp); > + if (error) > + return error; > + > + agi = agibp->b_addr; > + > + error = xfs_alloc_read_agf(mp, *tpp, agno, 0, &agfbp); > + if (error) > + return error; > + > + agf = agfbp->b_addr; > + if (XFS_IS_CORRUPT(mp, agf->agf_length != agi->agi_length)) > + return -EFSCORRUPTED; > + > + if (delta >= agi->agi_length) > + return -EINVAL; > + > + args.fsbno = XFS_AGB_TO_FSB(mp, agno, > + be32_to_cpu(agi->agi_length) - delta); > + > + /* remove the preallocations before allocation and re-establish then */ > + error = xfs_ag_resv_free(agibp->b_pag); > + if (error) > + return error; > + > + /* internal log shouldn't also show up in the free space btrees */ > + error = xfs_alloc_vextent(&args); > + if (!error && args.agbno == NULLAGBLOCK) > + error = -ENOSPC; > + > + if (error) { > + /* > + * if extent allocation fails, need to roll the transaction to > + * ensure that the AGFL fixup has been committed anyway. > + */ > + err2 = xfs_trans_roll(tpp); > + if (err2) > + return err2; > + goto resv_init_out; > + } > + > + /* > + * if successfully deleted from freespace btrees, need to confirm > + * per-AG reservation works as expected. > + */ > + be32_add_cpu(&agi->agi_length, -delta); > + be32_add_cpu(&agf->agf_length, -delta); > + > + err2 = xfs_ag_resv_init(agibp->b_pag, *tpp); > + if (err2) { > + be32_add_cpu(&agi->agi_length, delta); > + be32_add_cpu(&agf->agf_length, delta); > + if (err2 != -ENOSPC) > + goto resv_err; > + > + __xfs_bmap_add_free(*tpp, args.fsbno, delta, NULL, true); > + > + /* > + * Roll the transaction before trying to re-init the per-ag > + * reservation. The new transaction is clean so it will cancel > + * without any side effects. > + */ > + error = xfs_defer_finish(tpp); > + if (error) > + return error; > + > + error = -ENOSPC; > + goto resv_init_out; > + } > + xfs_ialloc_log_agi(*tpp, agibp, XFS_AGI_LENGTH); > + xfs_alloc_log_agf(*tpp, agfbp, XFS_AGF_LENGTH); > + return 0; > + > +resv_init_out: > + err2 = xfs_ag_resv_init(agibp->b_pag, *tpp); > + if (!err2) > + return error; > +resv_err: > + xfs_warn(mp, "Error %d reserving per-AG metadata reserve pool.", err2); > + xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE); > + return err2; > +} > + > /* > * Extent the AG indicated by the @id by the length passed in > */ > diff --git a/fs/xfs/libxfs/xfs_ag.h b/fs/xfs/libxfs/xfs_ag.h > index 5166322807e7..41293ebde8da 100644 > --- a/fs/xfs/libxfs/xfs_ag.h > +++ b/fs/xfs/libxfs/xfs_ag.h > @@ -24,8 +24,10 @@ struct aghdr_init_data { > }; > > int xfs_ag_init_headers(struct xfs_mount *mp, struct aghdr_init_data *id); > +int xfs_ag_shrink_space(struct xfs_mount *mp, struct xfs_trans **tpp, > + xfs_agnumber_t agno, xfs_extlen_t len); > int xfs_ag_extend_space(struct xfs_mount *mp, struct xfs_trans *tp, > - struct aghdr_init_data *id, xfs_extlen_t len); > + struct aghdr_init_data *id, xfs_extlen_t delta); > int xfs_ag_get_geometry(struct xfs_mount *mp, xfs_agnumber_t agno, > struct xfs_ag_geometry *ageo); > > -- > 2.27.0 >
On Fri, Mar 05, 2021 at 10:57:01AM +0800, Gao Xiang wrote: > This patch introduces a helper to shrink unused space in the last AG > by fixing up the freespace btree. > > Also make sure that the per-AG reservation works under the new AG > size. If such per-AG reservation or extent allocation fails, roll > the transaction so the new transaction could cancel without any side > effects. > > Signed-off-by: Gao Xiang <hsiangkao@redhat.com> > --- Looks mostly good to me. Some nits.. > fs/xfs/libxfs/xfs_ag.c | 111 +++++++++++++++++++++++++++++++++++++++++ > fs/xfs/libxfs/xfs_ag.h | 4 +- > 2 files changed, 114 insertions(+), 1 deletion(-) > > diff --git a/fs/xfs/libxfs/xfs_ag.c b/fs/xfs/libxfs/xfs_ag.c > index 9331f3516afa..1f6f9e70e1cb 100644 > --- a/fs/xfs/libxfs/xfs_ag.c > +++ b/fs/xfs/libxfs/xfs_ag.c ... > @@ -485,6 +490,112 @@ xfs_ag_init_headers( > return error; > } > > +int > +xfs_ag_shrink_space( > + struct xfs_mount *mp, > + struct xfs_trans **tpp, > + xfs_agnumber_t agno, > + xfs_extlen_t delta) > +{ > + struct xfs_alloc_arg args = { > + .tp = *tpp, > + .mp = mp, > + .type = XFS_ALLOCTYPE_THIS_BNO, > + .minlen = delta, > + .maxlen = delta, > + .oinfo = XFS_RMAP_OINFO_SKIP_UPDATE, > + .resv = XFS_AG_RESV_NONE, > + .prod = 1 > + }; > + struct xfs_buf *agibp, *agfbp; > + struct xfs_agi *agi; > + struct xfs_agf *agf; > + int error, err2; > + > + ASSERT(agno == mp->m_sb.sb_agcount - 1); > + error = xfs_ialloc_read_agi(mp, *tpp, agno, &agibp); > + if (error) > + return error; > + > + agi = agibp->b_addr; > + > + error = xfs_alloc_read_agf(mp, *tpp, agno, 0, &agfbp); > + if (error) > + return error; > + > + agf = agfbp->b_addr; > + if (XFS_IS_CORRUPT(mp, agf->agf_length != agi->agi_length)) > + return -EFSCORRUPTED; Is this check here for a reason? It seems a bit random, so I wonder if we should just leave the extra verification to buffer verifiers. > + > + if (delta >= agi->agi_length) > + return -EINVAL; > + > + args.fsbno = XFS_AGB_TO_FSB(mp, agno, > + be32_to_cpu(agi->agi_length) - delta); > + > + /* remove the preallocations before allocation and re-establish then */ The comment is a little confusing. Perhaps something like the following, if accurate..? /* * Disable perag reservations so it doesn't cause the allocation request * to fail. We'll reestablish reservation before we return. */ > + error = xfs_ag_resv_free(agibp->b_pag); > + if (error) > + return error; > + > + /* internal log shouldn't also show up in the free space btrees */ > + error = xfs_alloc_vextent(&args); > + if (!error && args.agbno == NULLAGBLOCK) > + error = -ENOSPC; > + > + if (error) { > + /* > + * if extent allocation fails, need to roll the transaction to > + * ensure that the AGFL fixup has been committed anyway. > + */ > + err2 = xfs_trans_roll(tpp); > + if (err2) > + return err2; > + goto resv_init_out; So if this fails and the transaction rolls, do we still hold the agi/agf buffers here? If not, there might be a window of time where it's possible for some other task to come in and alloc out of the AG without the perag res being active. > + } > + > + /* > + * if successfully deleted from freespace btrees, need to confirm > + * per-AG reservation works as expected. > + */ > + be32_add_cpu(&agi->agi_length, -delta); > + be32_add_cpu(&agf->agf_length, -delta); > + > + err2 = xfs_ag_resv_init(agibp->b_pag, *tpp); > + if (err2) { > + be32_add_cpu(&agi->agi_length, delta); > + be32_add_cpu(&agf->agf_length, delta); > + if (err2 != -ENOSPC) > + goto resv_err; > + > + __xfs_bmap_add_free(*tpp, args.fsbno, delta, NULL, true); > + > + /* > + * Roll the transaction before trying to re-init the per-ag > + * reservation. The new transaction is clean so it will cancel > + * without any side effects. > + */ > + error = xfs_defer_finish(tpp); > + if (error) > + return error; > + > + error = -ENOSPC; > + goto resv_init_out; > + } > + xfs_ialloc_log_agi(*tpp, agibp, XFS_AGI_LENGTH); > + xfs_alloc_log_agf(*tpp, agfbp, XFS_AGF_LENGTH); > + return 0; > + > +resv_init_out: > + err2 = xfs_ag_resv_init(agibp->b_pag, *tpp); > + if (!err2) > + return error; > +resv_err: > + xfs_warn(mp, "Error %d reserving per-AG metadata reserve pool.", err2); > + xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE); > + return err2; > +} > + > /* > * Extent the AG indicated by the @id by the length passed in > */ > diff --git a/fs/xfs/libxfs/xfs_ag.h b/fs/xfs/libxfs/xfs_ag.h > index 5166322807e7..41293ebde8da 100644 > --- a/fs/xfs/libxfs/xfs_ag.h > +++ b/fs/xfs/libxfs/xfs_ag.h > @@ -24,8 +24,10 @@ struct aghdr_init_data { > }; > > int xfs_ag_init_headers(struct xfs_mount *mp, struct aghdr_init_data *id); > +int xfs_ag_shrink_space(struct xfs_mount *mp, struct xfs_trans **tpp, > + xfs_agnumber_t agno, xfs_extlen_t len); > int xfs_ag_extend_space(struct xfs_mount *mp, struct xfs_trans *tp, > - struct aghdr_init_data *id, xfs_extlen_t len); > + struct aghdr_init_data *id, xfs_extlen_t delta); This looks misplaced..? Or maybe this is trying to make the APIs consistent, but the function definition still uses len as well as the declaration for _ag_shrink_space() (while the definition of that function uses delta). FWIW, the name delta tends to suggest a signed value to me based on our pattern of usage, whereas here it seems like these helpers always want a positive value (i.e. a length). Brian > int xfs_ag_get_geometry(struct xfs_mount *mp, xfs_agnumber_t agno, > struct xfs_ag_geometry *ageo); > > -- > 2.27.0 >
Hi Brian, On Mon, Mar 22, 2021 at 07:30:03AM -0400, Brian Foster wrote: > On Fri, Mar 05, 2021 at 10:57:01AM +0800, Gao Xiang wrote: > > This patch introduces a helper to shrink unused space in the last AG > > by fixing up the freespace btree. > > > > Also make sure that the per-AG reservation works under the new AG > > size. If such per-AG reservation or extent allocation fails, roll > > the transaction so the new transaction could cancel without any side > > effects. > > > > Signed-off-by: Gao Xiang <hsiangkao@redhat.com> > > --- > > Looks mostly good to me. Some nits.. > > > fs/xfs/libxfs/xfs_ag.c | 111 +++++++++++++++++++++++++++++++++++++++++ > > fs/xfs/libxfs/xfs_ag.h | 4 +- > > 2 files changed, 114 insertions(+), 1 deletion(-) > > > > diff --git a/fs/xfs/libxfs/xfs_ag.c b/fs/xfs/libxfs/xfs_ag.c > > index 9331f3516afa..1f6f9e70e1cb 100644 > > --- a/fs/xfs/libxfs/xfs_ag.c > > +++ b/fs/xfs/libxfs/xfs_ag.c > ... > > @@ -485,6 +490,112 @@ xfs_ag_init_headers( > > return error; > > } > > > > +int > > +xfs_ag_shrink_space( > > + struct xfs_mount *mp, > > + struct xfs_trans **tpp, > > + xfs_agnumber_t agno, > > + xfs_extlen_t delta) > > +{ > > + struct xfs_alloc_arg args = { > > + .tp = *tpp, > > + .mp = mp, > > + .type = XFS_ALLOCTYPE_THIS_BNO, > > + .minlen = delta, > > + .maxlen = delta, > > + .oinfo = XFS_RMAP_OINFO_SKIP_UPDATE, > > + .resv = XFS_AG_RESV_NONE, > > + .prod = 1 > > + }; > > + struct xfs_buf *agibp, *agfbp; > > + struct xfs_agi *agi; > > + struct xfs_agf *agf; > > + int error, err2; > > + > > + ASSERT(agno == mp->m_sb.sb_agcount - 1); > > + error = xfs_ialloc_read_agi(mp, *tpp, agno, &agibp); > > + if (error) > > + return error; > > + > > + agi = agibp->b_addr; > > + > > + error = xfs_alloc_read_agf(mp, *tpp, agno, 0, &agfbp); > > + if (error) > > + return error; > > + > > + agf = agfbp->b_addr; > > + if (XFS_IS_CORRUPT(mp, agf->agf_length != agi->agi_length)) > > + return -EFSCORRUPTED; > > Is this check here for a reason? It seems a bit random, so I wonder if > we should just leave the extra verification to buffer verifiers. It came from Darrick's thought. I'm fine with either way, but I feel confused if different conflict opinions here: https://lore.kernel.org/linux-xfs/20210303181931.GB3419940@magnolia/ > > > + > > + if (delta >= agi->agi_length) > > + return -EINVAL; > > + > > + args.fsbno = XFS_AGB_TO_FSB(mp, agno, > > + be32_to_cpu(agi->agi_length) - delta); > > + > > + /* remove the preallocations before allocation and re-establish then */ > > The comment is a little confusing. Perhaps something like the following, > if accurate..? > > /* > * Disable perag reservations so it doesn't cause the allocation request > * to fail. We'll reestablish reservation before we return. > */ ok, will update in the next version. > > > + error = xfs_ag_resv_free(agibp->b_pag); > > + if (error) > > + return error; > > + > > + /* internal log shouldn't also show up in the free space btrees */ > > + error = xfs_alloc_vextent(&args); > > + if (!error && args.agbno == NULLAGBLOCK) > > + error = -ENOSPC; > > + > > + if (error) { > > + /* > > + * if extent allocation fails, need to roll the transaction to > > + * ensure that the AGFL fixup has been committed anyway. > > + */ > > + err2 = xfs_trans_roll(tpp); > > + if (err2) > > + return err2; > > + goto resv_init_out; > > So if this fails and the transaction rolls, do we still hold the agi/agf > buffers here? If not, there might be a window of time where it's > possible for some other task to come in and alloc out of the AG without > the perag res being active. Yeah, I might need to bhold this, will update. > > > + } > > + > > + /* > > + * if successfully deleted from freespace btrees, need to confirm > > + * per-AG reservation works as expected. > > + */ > > + be32_add_cpu(&agi->agi_length, -delta); > > + be32_add_cpu(&agf->agf_length, -delta); > > + > > + err2 = xfs_ag_resv_init(agibp->b_pag, *tpp); > > + if (err2) { > > + be32_add_cpu(&agi->agi_length, delta); > > + be32_add_cpu(&agf->agf_length, delta); > > + if (err2 != -ENOSPC) > > + goto resv_err; > > + > > + __xfs_bmap_add_free(*tpp, args.fsbno, delta, NULL, true); > > + > > + /* > > + * Roll the transaction before trying to re-init the per-ag > > + * reservation. The new transaction is clean so it will cancel > > + * without any side effects. > > + */ > > + error = xfs_defer_finish(tpp); > > + if (error) > > + return error; > > + > > + error = -ENOSPC; > > + goto resv_init_out; > > + } > > + xfs_ialloc_log_agi(*tpp, agibp, XFS_AGI_LENGTH); > > + xfs_alloc_log_agf(*tpp, agfbp, XFS_AGF_LENGTH); > > + return 0; > > + > > +resv_init_out: > > + err2 = xfs_ag_resv_init(agibp->b_pag, *tpp); > > + if (!err2) > > + return error; > > +resv_err: > > + xfs_warn(mp, "Error %d reserving per-AG metadata reserve pool.", err2); > > + xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE); > > + return err2; > > +} > > + > > /* > > * Extent the AG indicated by the @id by the length passed in > > */ > > diff --git a/fs/xfs/libxfs/xfs_ag.h b/fs/xfs/libxfs/xfs_ag.h > > index 5166322807e7..41293ebde8da 100644 > > --- a/fs/xfs/libxfs/xfs_ag.h > > +++ b/fs/xfs/libxfs/xfs_ag.h > > @@ -24,8 +24,10 @@ struct aghdr_init_data { > > }; > > > > int xfs_ag_init_headers(struct xfs_mount *mp, struct aghdr_init_data *id); > > +int xfs_ag_shrink_space(struct xfs_mount *mp, struct xfs_trans **tpp, > > + xfs_agnumber_t agno, xfs_extlen_t len); > > int xfs_ag_extend_space(struct xfs_mount *mp, struct xfs_trans *tp, > > - struct aghdr_init_data *id, xfs_extlen_t len); > > + struct aghdr_init_data *id, xfs_extlen_t delta); > > This looks misplaced..? > > Or maybe this is trying to make the APIs consistent, but the function > definition still uses len as well as the declaration for > _ag_shrink_space() (while the definition of that function uses delta). > > FWIW, the name delta tends to suggest a signed value to me based on our > pattern of usage, whereas here it seems like these helpers always want a > positive value (i.e. a length). Yeah, it's just misplaced, thanks for pointing out, sorry about that. `delta' name came from, `len' is confusing to Darrick. https://lore.kernel.org/r/20210303182527.GC3419940@magnolia/ Thanks, Gao Xiang > > Brian > > > int xfs_ag_get_geometry(struct xfs_mount *mp, xfs_agnumber_t agno, > > struct xfs_ag_geometry *ageo); > > > > -- > > 2.27.0 > > >
On Mon, Mar 22, 2021 at 08:03:10PM +0800, Gao Xiang wrote: > Hi Brian, > > On Mon, Mar 22, 2021 at 07:30:03AM -0400, Brian Foster wrote: > > On Fri, Mar 05, 2021 at 10:57:01AM +0800, Gao Xiang wrote: > > > This patch introduces a helper to shrink unused space in the last AG > > > by fixing up the freespace btree. > > > > > > Also make sure that the per-AG reservation works under the new AG > > > size. If such per-AG reservation or extent allocation fails, roll > > > the transaction so the new transaction could cancel without any side > > > effects. > > > > > > Signed-off-by: Gao Xiang <hsiangkao@redhat.com> > > > --- > > > > Looks mostly good to me. Some nits.. > > > > > fs/xfs/libxfs/xfs_ag.c | 111 +++++++++++++++++++++++++++++++++++++++++ > > > fs/xfs/libxfs/xfs_ag.h | 4 +- > > > 2 files changed, 114 insertions(+), 1 deletion(-) > > > > > > diff --git a/fs/xfs/libxfs/xfs_ag.c b/fs/xfs/libxfs/xfs_ag.c > > > index 9331f3516afa..1f6f9e70e1cb 100644 > > > --- a/fs/xfs/libxfs/xfs_ag.c > > > +++ b/fs/xfs/libxfs/xfs_ag.c > > ... > > > @@ -485,6 +490,112 @@ xfs_ag_init_headers( > > > return error; > > > } > > > > > > +int > > > +xfs_ag_shrink_space( > > > + struct xfs_mount *mp, > > > + struct xfs_trans **tpp, > > > + xfs_agnumber_t agno, > > > + xfs_extlen_t delta) > > > +{ > > > + struct xfs_alloc_arg args = { > > > + .tp = *tpp, > > > + .mp = mp, > > > + .type = XFS_ALLOCTYPE_THIS_BNO, > > > + .minlen = delta, > > > + .maxlen = delta, > > > + .oinfo = XFS_RMAP_OINFO_SKIP_UPDATE, > > > + .resv = XFS_AG_RESV_NONE, > > > + .prod = 1 > > > + }; > > > + struct xfs_buf *agibp, *agfbp; > > > + struct xfs_agi *agi; > > > + struct xfs_agf *agf; > > > + int error, err2; > > > + > > > + ASSERT(agno == mp->m_sb.sb_agcount - 1); > > > + error = xfs_ialloc_read_agi(mp, *tpp, agno, &agibp); > > > + if (error) > > > + return error; > > > + > > > + agi = agibp->b_addr; > > > + > > > + error = xfs_alloc_read_agf(mp, *tpp, agno, 0, &agfbp); > > > + if (error) > > > + return error; > > > + > > > + agf = agfbp->b_addr; > > > + if (XFS_IS_CORRUPT(mp, agf->agf_length != agi->agi_length)) > > > + return -EFSCORRUPTED; > > > > Is this check here for a reason? It seems a bit random, so I wonder if > > we should just leave the extra verification to buffer verifiers. > > It came from Darrick's thought. I'm fine with either way, but I feel > confused if different conflict opinions here: > https://lore.kernel.org/linux-xfs/20210303181931.GB3419940@magnolia/ > Darrick's comment seems to refer to the check below. I'm referring to the check above that agi_length and agf_length match. Are they intended to go together? The check above seems to preexist the one below. Anyways, if so, maybe just bunch them together and add a comment: /* some extra paranoid checks before we shrink the ag */ if (XFS_IS_CORRUPT(...)) return -EFSCORRUPTED; if (delta >= agf->agf_length) return -EVINAL; > > > > > + > > > + if (delta >= agi->agi_length) > > > + return -EINVAL; > > > + > > > + args.fsbno = XFS_AGB_TO_FSB(mp, agno, > > > + be32_to_cpu(agi->agi_length) - delta); > > > + > > > + /* remove the preallocations before allocation and re-establish then */ ... > > > diff --git a/fs/xfs/libxfs/xfs_ag.h b/fs/xfs/libxfs/xfs_ag.h > > > index 5166322807e7..41293ebde8da 100644 > > > --- a/fs/xfs/libxfs/xfs_ag.h > > > +++ b/fs/xfs/libxfs/xfs_ag.h > > > @@ -24,8 +24,10 @@ struct aghdr_init_data { > > > }; > > > > > > int xfs_ag_init_headers(struct xfs_mount *mp, struct aghdr_init_data *id); > > > +int xfs_ag_shrink_space(struct xfs_mount *mp, struct xfs_trans **tpp, > > > + xfs_agnumber_t agno, xfs_extlen_t len); > > > int xfs_ag_extend_space(struct xfs_mount *mp, struct xfs_trans *tp, > > > - struct aghdr_init_data *id, xfs_extlen_t len); > > > + struct aghdr_init_data *id, xfs_extlen_t delta); > > > > This looks misplaced..? > > > > Or maybe this is trying to make the APIs consistent, but the function > > definition still uses len as well as the declaration for > > _ag_shrink_space() (while the definition of that function uses delta). > > > > FWIW, the name delta tends to suggest a signed value to me based on our > > pattern of usage, whereas here it seems like these helpers always want a > > positive value (i.e. a length). > > Yeah, it's just misplaced, thanks for pointing out, sorry about that. > `delta' name came from, `len' is confusing to Darrick. > https://lore.kernel.org/r/20210303182527.GC3419940@magnolia/ > Fair enough. I'm not worried about the name, just pointing out some potential inconsistencies. Brian > Thanks, > Gao Xiang > > > > > Brian > > > > > int xfs_ag_get_geometry(struct xfs_mount *mp, xfs_agnumber_t agno, > > > struct xfs_ag_geometry *ageo); > > > > > > -- > > > 2.27.0 > > > > > >
On Mon, Mar 22, 2021 at 08:25:55AM -0400, Brian Foster wrote: > On Mon, Mar 22, 2021 at 08:03:10PM +0800, Gao Xiang wrote: > > Hi Brian, > > > > On Mon, Mar 22, 2021 at 07:30:03AM -0400, Brian Foster wrote: > > > On Fri, Mar 05, 2021 at 10:57:01AM +0800, Gao Xiang wrote: > > > > This patch introduces a helper to shrink unused space in the last AG > > > > by fixing up the freespace btree. > > > > > > > > Also make sure that the per-AG reservation works under the new AG > > > > size. If such per-AG reservation or extent allocation fails, roll > > > > the transaction so the new transaction could cancel without any side > > > > effects. > > > > > > > > Signed-off-by: Gao Xiang <hsiangkao@redhat.com> > > > > --- > > > > > > Looks mostly good to me. Some nits.. > > > > > > > fs/xfs/libxfs/xfs_ag.c | 111 +++++++++++++++++++++++++++++++++++++++++ > > > > fs/xfs/libxfs/xfs_ag.h | 4 +- > > > > 2 files changed, 114 insertions(+), 1 deletion(-) > > > > > > > > diff --git a/fs/xfs/libxfs/xfs_ag.c b/fs/xfs/libxfs/xfs_ag.c > > > > index 9331f3516afa..1f6f9e70e1cb 100644 > > > > --- a/fs/xfs/libxfs/xfs_ag.c > > > > +++ b/fs/xfs/libxfs/xfs_ag.c > > > ... > > > > @@ -485,6 +490,112 @@ xfs_ag_init_headers( > > > > return error; > > > > } > > > > > > > > +int > > > > +xfs_ag_shrink_space( > > > > + struct xfs_mount *mp, > > > > + struct xfs_trans **tpp, > > > > + xfs_agnumber_t agno, > > > > + xfs_extlen_t delta) > > > > +{ > > > > + struct xfs_alloc_arg args = { > > > > + .tp = *tpp, > > > > + .mp = mp, > > > > + .type = XFS_ALLOCTYPE_THIS_BNO, > > > > + .minlen = delta, > > > > + .maxlen = delta, > > > > + .oinfo = XFS_RMAP_OINFO_SKIP_UPDATE, > > > > + .resv = XFS_AG_RESV_NONE, > > > > + .prod = 1 > > > > + }; > > > > + struct xfs_buf *agibp, *agfbp; > > > > + struct xfs_agi *agi; > > > > + struct xfs_agf *agf; > > > > + int error, err2; > > > > + > > > > + ASSERT(agno == mp->m_sb.sb_agcount - 1); > > > > + error = xfs_ialloc_read_agi(mp, *tpp, agno, &agibp); > > > > + if (error) > > > > + return error; > > > > + > > > > + agi = agibp->b_addr; > > > > + > > > > + error = xfs_alloc_read_agf(mp, *tpp, agno, 0, &agfbp); > > > > + if (error) > > > > + return error; > > > > + > > > > + agf = agfbp->b_addr; > > > > + if (XFS_IS_CORRUPT(mp, agf->agf_length != agi->agi_length)) > > > > + return -EFSCORRUPTED; > > > > > > Is this check here for a reason? It seems a bit random, so I wonder if > > > we should just leave the extra verification to buffer verifiers. > > > > It came from Darrick's thought. I'm fine with either way, but I feel > > confused if different conflict opinions here: > > https://lore.kernel.org/linux-xfs/20210303181931.GB3419940@magnolia/ > > > > Darrick's comment seems to refer to the check below. I'm referring to > the check above that agi_length and agf_length match. Are they intended > to go together? The check above seems to preexist the one below. Sorry, update link of this: https://lore.kernel.org/r/20210111181753.GC1164246@magnolia/ > > Anyways, if so, maybe just bunch them together and add a comment: > > /* some extra paranoid checks before we shrink the ag */ > if (XFS_IS_CORRUPT(...)) > return -EFSCORRUPTED; > if (delta >= agf->agf_length) > return -EVINAL; > ok, will update this. > > > > > > > + > > > > + if (delta >= agi->agi_length) > > > > + return -EINVAL; > > > > + > > > > + args.fsbno = XFS_AGB_TO_FSB(mp, agno, > > > > + be32_to_cpu(agi->agi_length) - delta); > > > > + > > > > + /* remove the preallocations before allocation and re-establish then */ > ... > > > > diff --git a/fs/xfs/libxfs/xfs_ag.h b/fs/xfs/libxfs/xfs_ag.h > > > > index 5166322807e7..41293ebde8da 100644 > > > > --- a/fs/xfs/libxfs/xfs_ag.h > > > > +++ b/fs/xfs/libxfs/xfs_ag.h > > > > @@ -24,8 +24,10 @@ struct aghdr_init_data { > > > > }; > > > > > > > > int xfs_ag_init_headers(struct xfs_mount *mp, struct aghdr_init_data *id); > > > > +int xfs_ag_shrink_space(struct xfs_mount *mp, struct xfs_trans **tpp, > > > > + xfs_agnumber_t agno, xfs_extlen_t len); > > > > int xfs_ag_extend_space(struct xfs_mount *mp, struct xfs_trans *tp, > > > > - struct aghdr_init_data *id, xfs_extlen_t len); > > > > + struct aghdr_init_data *id, xfs_extlen_t delta); > > > > > > This looks misplaced..? > > > > > > Or maybe this is trying to make the APIs consistent, but the function > > > definition still uses len as well as the declaration for > > > _ag_shrink_space() (while the definition of that function uses delta). > > > > > > FWIW, the name delta tends to suggest a signed value to me based on our > > > pattern of usage, whereas here it seems like these helpers always want a > > > positive value (i.e. a length). > > > > Yeah, it's just misplaced, thanks for pointing out, sorry about that. > > `delta' name came from, `len' is confusing to Darrick. > > https://lore.kernel.org/r/20210303182527.GC3419940@magnolia/ > > > > Fair enough. I'm not worried about the name, just pointing out some > potential inconsistencies. Thanks for pointing out! Thanks, Gao Xiang > > Brian > > > Thanks, > > Gao Xiang > > > > > > > > Brian > > > > > > > int xfs_ag_get_geometry(struct xfs_mount *mp, xfs_agnumber_t agno, > > > > struct xfs_ag_geometry *ageo); > > > > > > > > -- > > > > 2.27.0 > > > > > > > > > >
On Mon, Mar 22, 2021 at 08:33:28PM +0800, Gao Xiang wrote: > On Mon, Mar 22, 2021 at 08:25:55AM -0400, Brian Foster wrote: > > On Mon, Mar 22, 2021 at 08:03:10PM +0800, Gao Xiang wrote: > > > Hi Brian, > > > > > > On Mon, Mar 22, 2021 at 07:30:03AM -0400, Brian Foster wrote: > > > > On Fri, Mar 05, 2021 at 10:57:01AM +0800, Gao Xiang wrote: > > > > > This patch introduces a helper to shrink unused space in the last AG > > > > > by fixing up the freespace btree. > > > > > > > > > > Also make sure that the per-AG reservation works under the new AG > > > > > size. If such per-AG reservation or extent allocation fails, roll > > > > > the transaction so the new transaction could cancel without any side > > > > > effects. > > > > > > > > > > Signed-off-by: Gao Xiang <hsiangkao@redhat.com> > > > > > --- > > > > > > > > Looks mostly good to me. Some nits.. > > > > > > > > > fs/xfs/libxfs/xfs_ag.c | 111 +++++++++++++++++++++++++++++++++++++++++ > > > > > fs/xfs/libxfs/xfs_ag.h | 4 +- > > > > > 2 files changed, 114 insertions(+), 1 deletion(-) > > > > > > > > > > diff --git a/fs/xfs/libxfs/xfs_ag.c b/fs/xfs/libxfs/xfs_ag.c > > > > > index 9331f3516afa..1f6f9e70e1cb 100644 > > > > > --- a/fs/xfs/libxfs/xfs_ag.c > > > > > +++ b/fs/xfs/libxfs/xfs_ag.c > > > > ... > > > > > @@ -485,6 +490,112 @@ xfs_ag_init_headers( > > > > > return error; > > > > > } > > > > > > > > > > +int > > > > > +xfs_ag_shrink_space( > > > > > + struct xfs_mount *mp, > > > > > + struct xfs_trans **tpp, > > > > > + xfs_agnumber_t agno, > > > > > + xfs_extlen_t delta) > > > > > +{ > > > > > + struct xfs_alloc_arg args = { > > > > > + .tp = *tpp, > > > > > + .mp = mp, > > > > > + .type = XFS_ALLOCTYPE_THIS_BNO, > > > > > + .minlen = delta, > > > > > + .maxlen = delta, > > > > > + .oinfo = XFS_RMAP_OINFO_SKIP_UPDATE, > > > > > + .resv = XFS_AG_RESV_NONE, > > > > > + .prod = 1 > > > > > + }; > > > > > + struct xfs_buf *agibp, *agfbp; > > > > > + struct xfs_agi *agi; > > > > > + struct xfs_agf *agf; > > > > > + int error, err2; > > > > > + > > > > > + ASSERT(agno == mp->m_sb.sb_agcount - 1); > > > > > + error = xfs_ialloc_read_agi(mp, *tpp, agno, &agibp); > > > > > + if (error) > > > > > + return error; > > > > > + > > > > > + agi = agibp->b_addr; > > > > > + > > > > > + error = xfs_alloc_read_agf(mp, *tpp, agno, 0, &agfbp); > > > > > + if (error) > > > > > + return error; > > > > > + > > > > > + agf = agfbp->b_addr; > > > > > + if (XFS_IS_CORRUPT(mp, agf->agf_length != agi->agi_length)) > > > > > + return -EFSCORRUPTED; > > > > > > > > Is this check here for a reason? It seems a bit random, so I wonder if > > > > we should just leave the extra verification to buffer verifiers. > > > > > > It came from Darrick's thought. I'm fine with either way, but I feel > > > confused if different conflict opinions here: > > > https://lore.kernel.org/linux-xfs/20210303181931.GB3419940@magnolia/ > > > > > > > Darrick's comment seems to refer to the check below. I'm referring to > > the check above that agi_length and agf_length match. Are they intended > > to go together? The check above seems to preexist the one below. > > Sorry, update link of this: > https://lore.kernel.org/r/20210111181753.GC1164246@magnolia/ > > > > > Anyways, if so, maybe just bunch them together and add a comment: > > > > /* some extra paranoid checks before we shrink the ag */ Yes, all this is born out of paranoia checks on my part because I feel that shrink is likely to have Real Bad Dataloss Consequences(tm) if we don't check everything a second time before proceeding. --D > > if (XFS_IS_CORRUPT(...)) > > return -EFSCORRUPTED; > > if (delta >= agf->agf_length) > > return -EVINAL; > > > > ok, will update this. > > > > > > > > > > + > > > > > + if (delta >= agi->agi_length) > > > > > + return -EINVAL; > > > > > + > > > > > + args.fsbno = XFS_AGB_TO_FSB(mp, agno, > > > > > + be32_to_cpu(agi->agi_length) - delta); > > > > > + > > > > > + /* remove the preallocations before allocation and re-establish then */ > > ... > > > > > diff --git a/fs/xfs/libxfs/xfs_ag.h b/fs/xfs/libxfs/xfs_ag.h > > > > > index 5166322807e7..41293ebde8da 100644 > > > > > --- a/fs/xfs/libxfs/xfs_ag.h > > > > > +++ b/fs/xfs/libxfs/xfs_ag.h > > > > > @@ -24,8 +24,10 @@ struct aghdr_init_data { > > > > > }; > > > > > > > > > > int xfs_ag_init_headers(struct xfs_mount *mp, struct aghdr_init_data *id); > > > > > +int xfs_ag_shrink_space(struct xfs_mount *mp, struct xfs_trans **tpp, > > > > > + xfs_agnumber_t agno, xfs_extlen_t len); > > > > > int xfs_ag_extend_space(struct xfs_mount *mp, struct xfs_trans *tp, > > > > > - struct aghdr_init_data *id, xfs_extlen_t len); > > > > > + struct aghdr_init_data *id, xfs_extlen_t delta); > > > > > > > > This looks misplaced..? > > > > > > > > Or maybe this is trying to make the APIs consistent, but the function > > > > definition still uses len as well as the declaration for > > > > _ag_shrink_space() (while the definition of that function uses delta). > > > > > > > > FWIW, the name delta tends to suggest a signed value to me based on our > > > > pattern of usage, whereas here it seems like these helpers always want a > > > > positive value (i.e. a length). > > > > > > Yeah, it's just misplaced, thanks for pointing out, sorry about that. > > > `delta' name came from, `len' is confusing to Darrick. > > > https://lore.kernel.org/r/20210303182527.GC3419940@magnolia/ > > > > > > > Fair enough. I'm not worried about the name, just pointing out some > > potential inconsistencies. > > Thanks for pointing out! > > Thanks, > Gao Xiang > > > > > Brian > > > > > Thanks, > > > Gao Xiang > > > > > > > > > > > Brian > > > > > > > > > int xfs_ag_get_geometry(struct xfs_mount *mp, xfs_agnumber_t agno, > > > > > struct xfs_ag_geometry *ageo); > > > > > > > > > > -- > > > > > 2.27.0 > > > > > > > > > > > > > > >
diff --git a/fs/xfs/libxfs/xfs_ag.c b/fs/xfs/libxfs/xfs_ag.c index 9331f3516afa..1f6f9e70e1cb 100644 --- a/fs/xfs/libxfs/xfs_ag.c +++ b/fs/xfs/libxfs/xfs_ag.c @@ -22,6 +22,11 @@ #include "xfs_ag.h" #include "xfs_ag_resv.h" #include "xfs_health.h" +#include "xfs_error.h" +#include "xfs_bmap.h" +#include "xfs_defer.h" +#include "xfs_log_format.h" +#include "xfs_trans.h" static int xfs_get_aghdr_buf( @@ -485,6 +490,112 @@ xfs_ag_init_headers( return error; } +int +xfs_ag_shrink_space( + struct xfs_mount *mp, + struct xfs_trans **tpp, + xfs_agnumber_t agno, + xfs_extlen_t delta) +{ + struct xfs_alloc_arg args = { + .tp = *tpp, + .mp = mp, + .type = XFS_ALLOCTYPE_THIS_BNO, + .minlen = delta, + .maxlen = delta, + .oinfo = XFS_RMAP_OINFO_SKIP_UPDATE, + .resv = XFS_AG_RESV_NONE, + .prod = 1 + }; + struct xfs_buf *agibp, *agfbp; + struct xfs_agi *agi; + struct xfs_agf *agf; + int error, err2; + + ASSERT(agno == mp->m_sb.sb_agcount - 1); + error = xfs_ialloc_read_agi(mp, *tpp, agno, &agibp); + if (error) + return error; + + agi = agibp->b_addr; + + error = xfs_alloc_read_agf(mp, *tpp, agno, 0, &agfbp); + if (error) + return error; + + agf = agfbp->b_addr; + if (XFS_IS_CORRUPT(mp, agf->agf_length != agi->agi_length)) + return -EFSCORRUPTED; + + if (delta >= agi->agi_length) + return -EINVAL; + + args.fsbno = XFS_AGB_TO_FSB(mp, agno, + be32_to_cpu(agi->agi_length) - delta); + + /* remove the preallocations before allocation and re-establish then */ + error = xfs_ag_resv_free(agibp->b_pag); + if (error) + return error; + + /* internal log shouldn't also show up in the free space btrees */ + error = xfs_alloc_vextent(&args); + if (!error && args.agbno == NULLAGBLOCK) + error = -ENOSPC; + + if (error) { + /* + * if extent allocation fails, need to roll the transaction to + * ensure that the AGFL fixup has been committed anyway. + */ + err2 = xfs_trans_roll(tpp); + if (err2) + return err2; + goto resv_init_out; + } + + /* + * if successfully deleted from freespace btrees, need to confirm + * per-AG reservation works as expected. + */ + be32_add_cpu(&agi->agi_length, -delta); + be32_add_cpu(&agf->agf_length, -delta); + + err2 = xfs_ag_resv_init(agibp->b_pag, *tpp); + if (err2) { + be32_add_cpu(&agi->agi_length, delta); + be32_add_cpu(&agf->agf_length, delta); + if (err2 != -ENOSPC) + goto resv_err; + + __xfs_bmap_add_free(*tpp, args.fsbno, delta, NULL, true); + + /* + * Roll the transaction before trying to re-init the per-ag + * reservation. The new transaction is clean so it will cancel + * without any side effects. + */ + error = xfs_defer_finish(tpp); + if (error) + return error; + + error = -ENOSPC; + goto resv_init_out; + } + xfs_ialloc_log_agi(*tpp, agibp, XFS_AGI_LENGTH); + xfs_alloc_log_agf(*tpp, agfbp, XFS_AGF_LENGTH); + return 0; + +resv_init_out: + err2 = xfs_ag_resv_init(agibp->b_pag, *tpp); + if (!err2) + return error; +resv_err: + xfs_warn(mp, "Error %d reserving per-AG metadata reserve pool.", err2); + xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE); + return err2; +} + /* * Extent the AG indicated by the @id by the length passed in */ diff --git a/fs/xfs/libxfs/xfs_ag.h b/fs/xfs/libxfs/xfs_ag.h index 5166322807e7..41293ebde8da 100644 --- a/fs/xfs/libxfs/xfs_ag.h +++ b/fs/xfs/libxfs/xfs_ag.h @@ -24,8 +24,10 @@ struct aghdr_init_data { }; int xfs_ag_init_headers(struct xfs_mount *mp, struct aghdr_init_data *id); +int xfs_ag_shrink_space(struct xfs_mount *mp, struct xfs_trans **tpp, + xfs_agnumber_t agno, xfs_extlen_t len); int xfs_ag_extend_space(struct xfs_mount *mp, struct xfs_trans *tp, - struct aghdr_init_data *id, xfs_extlen_t len); + struct aghdr_init_data *id, xfs_extlen_t delta); int xfs_ag_get_geometry(struct xfs_mount *mp, xfs_agnumber_t agno, struct xfs_ag_geometry *ageo);
This patch introduces a helper to shrink unused space in the last AG by fixing up the freespace btree. Also make sure that the per-AG reservation works under the new AG size. If such per-AG reservation or extent allocation fails, roll the transaction so the new transaction could cancel without any side effects. Signed-off-by: Gao Xiang <hsiangkao@redhat.com> --- fs/xfs/libxfs/xfs_ag.c | 111 +++++++++++++++++++++++++++++++++++++++++ fs/xfs/libxfs/xfs_ag.h | 4 +- 2 files changed, 114 insertions(+), 1 deletion(-)