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xfs: add an extent to the rmap btree

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

Now all the btree, free space and transaction infrastructure is in
place, we can finally add the code to insert reverse mappings to the
rmap btree. Freeing will be done in a separate patch, so just the
addition operation can be focussed on here.

[darrick: handle owner offsets when adding rmaps]
[dchinner: remove remaining debug printk statements]
[darrick: move unwritten bit to 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>
Signed-off-by: Dave Chinner <david@fromorbit.com>
This commit is contained in:
Darrick J. Wong 2016-08-03 11:44:21 +10:00 committed by Dave Chinner
parent aa966d84aa
commit 0a1b0b3855
2 changed files with 223 additions and 5 deletions
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226
fs/xfs/libxfs/xfs_rmap.c
View File

@ -31,6 +31,7 @@
#include "xfs_trans.h"
#include "xfs_alloc.h"
#include "xfs_rmap.h"
#include "xfs_rmap_btree.h"
#include "xfs_trans_space.h"
#include "xfs_trace.h"
#include "xfs_error.h"
@ -158,6 +159,218 @@ out_error:
return error;
}
/*
* A mergeable rmap must have the same owner and the same values for
* the unwritten, attr_fork, and bmbt flags. The startblock and
* offset are checked separately.
*/
static bool
xfs_rmap_is_mergeable(
struct xfs_rmap_irec *irec,
uint64_t owner,
unsigned int flags)
{
if (irec->rm_owner == XFS_RMAP_OWN_NULL)
return false;
if (irec->rm_owner != owner)
return false;
if ((flags & XFS_RMAP_UNWRITTEN) ^
(irec->rm_flags & XFS_RMAP_UNWRITTEN))
return false;
if ((flags & XFS_RMAP_ATTR_FORK) ^
(irec->rm_flags & XFS_RMAP_ATTR_FORK))
return false;
if ((flags & XFS_RMAP_BMBT_BLOCK) ^
(irec->rm_flags & XFS_RMAP_BMBT_BLOCK))
return false;
return true;
}
/*
* When we allocate a new block, the first thing we do is add a reference to
* the extent in the rmap btree. This takes the form of a [agbno, length,
* owner, offset] record. Flags are encoded in the high bits of the offset
* field.
*/
STATIC int
xfs_rmap_map(
struct xfs_btree_cur *cur,
xfs_agblock_t bno,
xfs_extlen_t len,
bool unwritten,
struct xfs_owner_info *oinfo)
{
struct xfs_mount *mp = cur->bc_mp;
struct xfs_rmap_irec ltrec;
struct xfs_rmap_irec gtrec;
int have_gt;
int have_lt;
int error = 0;
int i;
uint64_t owner;
uint64_t offset;
unsigned int flags = 0;
bool ignore_off;
xfs_owner_info_unpack(oinfo, &owner, &offset, &flags);
ASSERT(owner != 0);
ignore_off = XFS_RMAP_NON_INODE_OWNER(owner) ||
(flags & XFS_RMAP_BMBT_BLOCK);
if (unwritten)
flags |= XFS_RMAP_UNWRITTEN;
trace_xfs_rmap_map(mp, cur->bc_private.a.agno, bno, len,
unwritten, oinfo);
/*
* For the initial lookup, look for an exact match or the left-adjacent
* record for our insertion point. This will also give us the record for
* start block contiguity tests.
*/
error = xfs_rmap_lookup_le(cur, bno, len, owner, offset, flags,
&have_lt);
if (error)
goto out_error;
XFS_WANT_CORRUPTED_GOTO(mp, have_lt == 1, out_error);
error = xfs_rmap_get_rec(cur, &ltrec, &have_lt);
if (error)
goto out_error;
XFS_WANT_CORRUPTED_GOTO(mp, have_lt == 1, out_error);
trace_xfs_rmap_lookup_le_range_result(cur->bc_mp,
cur->bc_private.a.agno, ltrec.rm_startblock,
ltrec.rm_blockcount, ltrec.rm_owner,
ltrec.rm_offset, ltrec.rm_flags);
if (!xfs_rmap_is_mergeable(&ltrec, owner, flags))
have_lt = 0;
XFS_WANT_CORRUPTED_GOTO(mp,
have_lt == 0 ||
ltrec.rm_startblock + ltrec.rm_blockcount <= bno, out_error);
/*
* Increment the cursor to see if we have a right-adjacent record to our
* insertion point. This will give us the record for end block
* contiguity tests.
*/
error = xfs_btree_increment(cur, 0, &have_gt);
if (error)
goto out_error;
if (have_gt) {
error = xfs_rmap_get_rec(cur, &gtrec, &have_gt);
if (error)
goto out_error;
XFS_WANT_CORRUPTED_GOTO(mp, have_gt == 1, out_error);
XFS_WANT_CORRUPTED_GOTO(mp, bno + len <= gtrec.rm_startblock,
out_error);
trace_xfs_rmap_find_right_neighbor_result(cur->bc_mp,
cur->bc_private.a.agno, gtrec.rm_startblock,
gtrec.rm_blockcount, gtrec.rm_owner,
gtrec.rm_offset, gtrec.rm_flags);
if (!xfs_rmap_is_mergeable(&gtrec, owner, flags))
have_gt = 0;
}
/*
* Note: cursor currently points one record to the right of ltrec, even
* if there is no record in the tree to the right.
*/
if (have_lt &&
ltrec.rm_startblock + ltrec.rm_blockcount == bno &&
(ignore_off || ltrec.rm_offset + ltrec.rm_blockcount == offset)) {
/*
* left edge contiguous, merge into left record.
*
* ltbno ltlen
* orig: |ooooooooo|
* adding: |aaaaaaaaa|
* result: |rrrrrrrrrrrrrrrrrrr|
* bno len
*/
ltrec.rm_blockcount += len;
if (have_gt &&
bno + len == gtrec.rm_startblock &&
(ignore_off || offset + len == gtrec.rm_offset) &&
(unsigned long)ltrec.rm_blockcount + len +
gtrec.rm_blockcount <= XFS_RMAP_LEN_MAX) {
/*
* right edge also contiguous, delete right record
* and merge into left record.
*
* ltbno ltlen gtbno gtlen
* orig: |ooooooooo| |ooooooooo|
* adding: |aaaaaaaaa|
* result: |rrrrrrrrrrrrrrrrrrrrrrrrrrrrr|
*/
ltrec.rm_blockcount += gtrec.rm_blockcount;
trace_xfs_rmap_delete(mp, cur->bc_private.a.agno,
gtrec.rm_startblock,
gtrec.rm_blockcount,
gtrec.rm_owner,
gtrec.rm_offset,
gtrec.rm_flags);
error = xfs_btree_delete(cur, &i);
if (error)
goto out_error;
XFS_WANT_CORRUPTED_GOTO(mp, i == 1, out_error);
}
/* point the cursor back to the left record and update */
error = xfs_btree_decrement(cur, 0, &have_gt);
if (error)
goto out_error;
error = xfs_rmap_update(cur, &ltrec);
if (error)
goto out_error;
} else if (have_gt &&
bno + len == gtrec.rm_startblock &&
(ignore_off || offset + len == gtrec.rm_offset)) {
/*
* right edge contiguous, merge into right record.
*
* gtbno gtlen
* Orig: |ooooooooo|
* adding: |aaaaaaaaa|
* Result: |rrrrrrrrrrrrrrrrrrr|
* bno len
*/
gtrec.rm_startblock = bno;
gtrec.rm_blockcount += len;
if (!ignore_off)
gtrec.rm_offset = offset;
error = xfs_rmap_update(cur, &gtrec);
if (error)
goto out_error;
} else {
/*
* no contiguous edge with identical owner, insert
* new record at current cursor position.
*/
cur->bc_rec.r.rm_startblock = bno;
cur->bc_rec.r.rm_blockcount = len;
cur->bc_rec.r.rm_owner = owner;
cur->bc_rec.r.rm_offset = offset;
cur->bc_rec.r.rm_flags = flags;
trace_xfs_rmap_insert(mp, cur->bc_private.a.agno, bno, len,
owner, offset, flags);
error = xfs_btree_insert(cur, &i);
if (error)
goto out_error;
XFS_WANT_CORRUPTED_GOTO(mp, i == 1, out_error);
}
trace_xfs_rmap_map_done(mp, cur->bc_private.a.agno, bno, len,
unwritten, oinfo);
out_error:
if (error)
trace_xfs_rmap_map_error(mp, cur->bc_private.a.agno,
error, _RET_IP_);
return error;
}
/*
* Add a reference to an extent in the rmap btree.
*/
int
xfs_rmap_alloc(
struct xfs_trans *tp,
@ -168,19 +381,22 @@ xfs_rmap_alloc(
struct xfs_owner_info *oinfo)
{
struct xfs_mount *mp = tp->t_mountp;
int error = 0;
struct xfs_btree_cur *cur;
int error;
if (!xfs_sb_version_hasrmapbt(&mp->m_sb))
return 0;
trace_xfs_rmap_map(mp, agno, bno, len, false, oinfo);
if (1)
cur = xfs_rmapbt_init_cursor(mp, tp, agbp, agno);
error = xfs_rmap_map(cur, bno, len, false, oinfo);
if (error)
goto out_error;
trace_xfs_rmap_map_done(mp, agno, bno, len, false, oinfo);
xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
return 0;
out_error:
trace_xfs_rmap_map_error(mp, agno, error, _RET_IP_);
xfs_btree_del_cursor(cur, XFS_BTREE_ERROR);
return error;
}

2
fs/xfs/xfs_trace.h
View File

@ -2551,6 +2551,8 @@ DEFINE_RMAPBT_EVENT(xfs_rmap_delete);
DEFINE_AG_ERROR_EVENT(xfs_rmap_insert_error);
DEFINE_AG_ERROR_EVENT(xfs_rmap_delete_error);
DEFINE_AG_ERROR_EVENT(xfs_rmap_update_error);
DEFINE_RMAPBT_EVENT(xfs_rmap_lookup_le_range_result);
DEFINE_RMAPBT_EVENT(xfs_rmap_find_right_neighbor_result);
#endif /* _TRACE_XFS_H */