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xfs: define the on-disk rmap btree format

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Originally-From: Dave Chinner <dchinner@redhat.com>

Now we have all the surrounding call infrastructure in place, we can
start filling out the rmap btree implementation. Start with the
on-disk btree format; add everything needed to read, write and
manipulate rmap btree blocks. This prepares the way for adding the
btree operations implementation.

[darrick: record owner and offset info in rmap btree]
[darrick: fork, bmbt and unwritten state in rmap btree]
[darrick: flags are a separate field in xfs_rmap_irec]
[darrick: calculate maxlevels separately]
[darrick: move the 'unwritten' bit into unused parts of rm_offset]

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
This commit is contained in:
Darrick J. Wong
2016-08-03 11:36:07 +10:00
committed by Dave Chinner
parent 673930c34a
commit 035e00acb5
13 changed files with 415 additions and 8 deletions
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73
fs/xfs/libxfs/xfs_format.h
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@@ -1347,6 +1347,79 @@ struct xfs_owner_info {
#define XFS_RMAP_OWN_INODES (-7ULL) /* Inode chunk */
#define XFS_RMAP_OWN_MIN (-8ULL) /* guard */
#define XFS_RMAP_NON_INODE_OWNER(owner) (!!((owner) & (1ULL << 63)))
/*
* Data record structure
*/
struct xfs_rmap_rec {
__be32 rm_startblock; /* extent start block */
__be32 rm_blockcount; /* extent length */
__be64 rm_owner; /* extent owner */
__be64 rm_offset; /* offset within the owner */
};
/*
* rmap btree record
* rm_offset:63 is the attribute fork flag
* rm_offset:62 is the bmbt block flag
* rm_offset:61 is the unwritten extent flag (same as l0:63 in bmbt)
* rm_offset:54-60 aren't used and should be zero
* rm_offset:0-53 is the block offset within the inode
*/
#define XFS_RMAP_OFF_ATTR_FORK ((__uint64_t)1ULL << 63)
#define XFS_RMAP_OFF_BMBT_BLOCK ((__uint64_t)1ULL << 62)
#define XFS_RMAP_OFF_UNWRITTEN ((__uint64_t)1ULL << 61)
#define XFS_RMAP_LEN_MAX ((__uint32_t)~0U)
#define XFS_RMAP_OFF_FLAGS (XFS_RMAP_OFF_ATTR_FORK | \
XFS_RMAP_OFF_BMBT_BLOCK | \
XFS_RMAP_OFF_UNWRITTEN)
#define XFS_RMAP_OFF_MASK ((__uint64_t)0x3FFFFFFFFFFFFFULL)
#define XFS_RMAP_OFF(off) ((off) & XFS_RMAP_OFF_MASK)
#define XFS_RMAP_IS_BMBT_BLOCK(off) (!!((off) & XFS_RMAP_OFF_BMBT_BLOCK))
#define XFS_RMAP_IS_ATTR_FORK(off) (!!((off) & XFS_RMAP_OFF_ATTR_FORK))
#define XFS_RMAP_IS_UNWRITTEN(len) (!!((off) & XFS_RMAP_OFF_UNWRITTEN))
#define RMAPBT_STARTBLOCK_BITLEN 32
#define RMAPBT_BLOCKCOUNT_BITLEN 32
#define RMAPBT_OWNER_BITLEN 64
#define RMAPBT_ATTRFLAG_BITLEN 1
#define RMAPBT_BMBTFLAG_BITLEN 1
#define RMAPBT_EXNTFLAG_BITLEN 1
#define RMAPBT_UNUSED_OFFSET_BITLEN 7
#define RMAPBT_OFFSET_BITLEN 54
#define XFS_RMAP_ATTR_FORK (1 << 0)
#define XFS_RMAP_BMBT_BLOCK (1 << 1)
#define XFS_RMAP_UNWRITTEN (1 << 2)
#define XFS_RMAP_KEY_FLAGS (XFS_RMAP_ATTR_FORK | \
XFS_RMAP_BMBT_BLOCK)
#define XFS_RMAP_REC_FLAGS (XFS_RMAP_UNWRITTEN)
struct xfs_rmap_irec {
xfs_agblock_t rm_startblock; /* extent start block */
xfs_extlen_t rm_blockcount; /* extent length */
__uint64_t rm_owner; /* extent owner */
__uint64_t rm_offset; /* offset within the owner */
unsigned int rm_flags; /* state flags */
};
/*
* Key structure
*
* We don't use the length for lookups
*/
struct xfs_rmap_key {
__be32 rm_startblock; /* extent start block */
__be64 rm_owner; /* extent owner */
__be64 rm_offset; /* offset within the owner */
} __attribute__((packed));
/* btree pointer type */
typedef __be32 xfs_rmap_ptr_t;
#define XFS_RMAP_BLOCK(mp) \
(xfs_sb_version_hasfinobt(&((mp)->m_sb)) ? \
XFS_FIBT_BLOCK(mp) + 1 : \