Re: [PATCH 05/20] xfs: introduce rmap btree definitions

Darrick J. Wong
2015-06-03T06:35:02Z

On Tue, Jun 02, 2015 at 11:30:22PM -0700, Darrick J. Wong wrote:
> On Wed, Jun 03, 2015 at 04:04:42PM +1000, Dave Chinner wrote:
> > From: Dave Chinner <dchinner@redhat.com>
> >
> > Add new per-ag rmap btree definitions to the per-ag structures. The
> > rmap btree will sit inthe empty slots on disk after the free space
> > btrees, and hence form a part of the array of space management
> > btrees. This requires the definition of the btree to be contiguous
> > with the free space btrees.
> >
> > Signed-off-by: Dave Chinner <dchinner@redhat.com>
> > ---
> > fs/xfs/libxfs/xfs_alloc.c | 6 ++++++
> > fs/xfs/libxfs/xfs_btree.c | 4 ++--
> > fs/xfs/libxfs/xfs_btree.h | 3 +++
> > fs/xfs/libxfs/xfs_format.h | 22 +++++++++++++++++-----
> > fs/xfs/libxfs/xfs_types.h | 4 ++--
> > 5 files changed, 30 insertions(+), 9 deletions(-)
> >
> > diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c
> > index d4aa844..c7206b5 100644
> > --- a/fs/xfs/libxfs/xfs_alloc.c
> > +++ b/fs/xfs/libxfs/xfs_alloc.c
> > @@ -2267,6 +2267,10 @@ xfs_agf_verify(
> > be32_to_cpu(agf->agf_levels[XFS_BTNUM_CNT]) > XFS_BTREE_MAXLEVELS)
> > return false;
> >
> > + if (xfs_sb_version_hasrmapbt(&mp->m_sb) &&
> > + be32_to_cpu(agf->agf_levels[XFS_BTNUM_RMAP]) > XFS_BTREE_MAXLEVELS)
> > + return false;
> > +
> > /*
> > * during growfs operations, the perag is not fully initialised,
> > * so we can't use it for any useful checking. growfs ensures we can't
> > @@ -2397,6 +2401,8 @@ xfs_alloc_read_agf(
> > be32_to_cpu(agf->agf_levels[XFS_BTNUM_BNOi]);
> > pag->pagf_levels[XFS_BTNUM_CNTi] =
> > be32_to_cpu(agf->agf_levels[XFS_BTNUM_CNTi]);
> > + pag->pagf_levels[XFS_BTNUM_RMAPi] =
> > + be32_to_cpu(agf->agf_levels[XFS_BTNUM_RMAPi]);
> > spin_lock_init(&pag->pagb_lock);
> > pag->pagb_count = 0;
> > pag->pagb_tree = RB_ROOT;
> > diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c
> > index c72283d..0426152 100644
> > --- a/fs/xfs/libxfs/xfs_btree.c
> > +++ b/fs/xfs/libxfs/xfs_btree.c
> > @@ -42,9 +42,9 @@ kmem_zone_t *xfs_btree_cur_zone;
> > * Btree magic numbers.
> > */
> > static const __uint32_t xfs_magics[2][XFS_BTNUM_MAX] = {
> > - { XFS_ABTB_MAGIC, XFS_ABTC_MAGIC, XFS_BMAP_MAGIC, XFS_IBT_MAGIC,
> > + { XFS_ABTB_MAGIC, XFS_ABTC_MAGIC, 0, XFS_BMAP_MAGIC, XFS_IBT_MAGIC,
> > XFS_FIBT_MAGIC },
> > - { XFS_ABTB_CRC_MAGIC, XFS_ABTC_CRC_MAGIC,
> > + { XFS_ABTB_CRC_MAGIC, XFS_ABTC_CRC_MAGIC, XFS_RMAP_CRC_MAGIC,
> > XFS_BMAP_CRC_MAGIC, XFS_IBT_CRC_MAGIC, XFS_FIBT_CRC_MAGIC }
> > };
> > #define xfs_btree_magic(cur) \
> > diff --git a/fs/xfs/libxfs/xfs_btree.h b/fs/xfs/libxfs/xfs_btree.h
> > index 8f18bab..ace1995 100644
> > --- a/fs/xfs/libxfs/xfs_btree.h
> > +++ b/fs/xfs/libxfs/xfs_btree.h
> > @@ -63,6 +63,7 @@ union xfs_btree_rec {
> > #define XFS_BTNUM_BMAP ((xfs_btnum_t)XFS_BTNUM_BMAPi)
> > #define XFS_BTNUM_INO ((xfs_btnum_t)XFS_BTNUM_INOi)
> > #define XFS_BTNUM_FINO ((xfs_btnum_t)XFS_BTNUM_FINOi)
> > +#define XFS_BTNUM_RMAP ((xfs_btnum_t)XFS_BTNUM_RMAPi)
> >
> > /*
> > * For logging record fields.
> > @@ -94,6 +95,7 @@ do { \
> > case XFS_BTNUM_BMAP: __XFS_BTREE_STATS_INC(bmbt, stat); break; \
> > case XFS_BTNUM_INO: __XFS_BTREE_STATS_INC(ibt, stat); break; \
> > case XFS_BTNUM_FINO: __XFS_BTREE_STATS_INC(fibt, stat); break; \
> > + case XFS_BTNUM_RMAP: break; \
>
> Hmm, so we don't have to provide stats for all the btrees?

Aha, they're in the later patches, which my mailer helpfully ... delivered
later.

I think I need sleep. Disregard most of this email. :)

I'll move the reflink fields so they don't conflict, and read these patches
more closely tomorrow. Sorry for the noise.

--D

>
> <shrug> Actually, I thought it was rather clever that one could grep
> /proc/fs/xfs/stat for 'rlbt' to find out if the running xfs driver supports
> reflink.
>
> (Not that I want someone to think this is some kind of ABI...)
>
> > case XFS_BTNUM_MAX: ASSERT(0); /* fucking gcc */ ; break; \
> > } \
> > } while (0)
> > @@ -108,6 +110,7 @@ do { \
> > case XFS_BTNUM_BMAP: __XFS_BTREE_STATS_ADD(bmbt, stat, val); break; \
> > case XFS_BTNUM_INO: __XFS_BTREE_STATS_ADD(ibt, stat, val); break; \
> > case XFS_BTNUM_FINO: __XFS_BTREE_STATS_ADD(fibt, stat, val); break; \
> > + case XFS_BTNUM_RMAP: break; \
> > case XFS_BTNUM_MAX: ASSERT(0); /* fucking gcc */ ; break; \
> > } \
> > } while (0)
> > diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
> > index a0ae572..d120af4 100644
> > --- a/fs/xfs/libxfs/xfs_format.h
> > +++ b/fs/xfs/libxfs/xfs_format.h
> > @@ -445,6 +445,7 @@ xfs_sb_has_compat_feature(
> > }
> >
> > #define XFS_SB_FEAT_RO_COMPAT_FINOBT (1 << 0) /* free inode btree */
> > +#define XFS_SB_FEAT_RO_COMPAT_RMAPBT (1 << 1) /* reverse map btree */
> > #define XFS_SB_FEAT_RO_COMPAT_ALL \
> > (XFS_SB_FEAT_RO_COMPAT_FINOBT)
>
> ... | XFS_SB_FEAT_RO_COMPAT_RMAPBT) ?
>
> (/me shifts the reflink feature flag to (1 << 2))
>
> > #define XFS_SB_FEAT_RO_COMPAT_UNKNOWN ~XFS_SB_FEAT_RO_COMPAT_ALL
> > @@ -514,6 +515,12 @@ static inline bool xfs_sb_version_hassparseinodes(struct xfs_sb *sbp)
> > xfs_sb_has_incompat_feature(sbp, XFS_SB_FEAT_INCOMPAT_SPINODES);
> > }
> >
> > +static inline bool xfs_sb_version_hasrmapbt(struct xfs_sb *sbp)
> > +{
> > + return (XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5) &&
> > + (sbp->sb_features_ro_compat & XFS_SB_FEAT_RO_COMPAT_RMAPBT);
> > +}
> > +
> > /*
> > * end of superblock version macros
> > */
> > @@ -574,10 +581,10 @@ xfs_is_quota_inode(struct xfs_sb *sbp, xfs_ino_t ino)
> > #define XFS_AGI_GOOD_VERSION(v) ((v) == XFS_AGI_VERSION)
> >
> > /*
> > - * Btree number 0 is bno, 1 is cnt. This value gives the size of the
> > + * Btree number 0 is bno, 1 is cnt, 2 is rmap. This value gives the size of the
> > * arrays below.
> > */
> > -#define XFS_BTNUM_AGF ((int)XFS_BTNUM_CNTi + 1)
> > +#define XFS_BTNUM_AGF ((int)XFS_BTNUM_RMAPi + 1)
> >
> > /*
> > * The second word of agf_levels in the first a.g. overlaps the EFS
> > @@ -594,12 +601,10 @@ typedef struct xfs_agf {
> > __be32 agf_seqno; /* sequence # starting from 0 */
> > __be32 agf_length; /* size in blocks of a.g. */
> > /*
> > - * Freespace information
> > + * Freespace and rmap information
> > */
> > __be32 agf_roots[XFS_BTNUM_AGF]; /* root blocks */
> > - __be32 agf_spare0; /* spare field */
> > __be32 agf_levels[XFS_BTNUM_AGF]; /* btree levels */
> > - __be32 agf_spare1; /* spare field */
>
> Doh, field collision! :)
>
> Guess I'll use up one of the agf_spare64's.
>
> --D
>
> >
> > __be32 agf_flfirst; /* first freelist block's index */
> > __be32 agf_fllast; /* last freelist block's index */
> > @@ -1277,6 +1282,13 @@ typedef __be32 xfs_inobt_ptr_t;
> > #define XFS_FIBT_BLOCK(mp) ((xfs_agblock_t)(XFS_IBT_BLOCK(mp) + 1))
> >
> > /*
> > + * Reverse mapping btree format definitions
> > + *
> > + * There is a btree for the reverse map per allocation group
> > + */
> > +#define XFS_RMAP_CRC_MAGIC 0x524d4233 /* 'RMB3' */
> > +
> > +/*
> > * The first data block of an AG depends on whether the filesystem was formatted
> > * with the finobt feature. If so, account for the finobt reserved root btree
> > * block.
> > diff --git a/fs/xfs/libxfs/xfs_types.h b/fs/xfs/libxfs/xfs_types.h
> > index b79dc66..3d50364 100644
> > --- a/fs/xfs/libxfs/xfs_types.h
> > +++ b/fs/xfs/libxfs/xfs_types.h
> > @@ -108,8 +108,8 @@ typedef enum {
> > } xfs_lookup_t;
> >
> > typedef enum {
> > - XFS_BTNUM_BNOi, XFS_BTNUM_CNTi, XFS_BTNUM_BMAPi, XFS_BTNUM_INOi,
> > - XFS_BTNUM_FINOi, XFS_BTNUM_MAX
> > + XFS_BTNUM_BNOi, XFS_BTNUM_CNTi, XFS_BTNUM_RMAPi, XFS_BTNUM_BMAPi,
> > + XFS_BTNUM_INOi, XFS_BTNUM_FINOi, XFS_BTNUM_MAX
> > } xfs_btnum_t;
> >
> > struct xfs_name {
> > --
> > 2.0.0
> >
> > _______________________________________________
> > xfs mailing list
> > xfs@oss.sgi.com
> > http://oss.sgi.com/mailman/listinfo/xfs
>
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