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xfs: clean up weird while loop in xfs_alloc_ag_vextent_near 

Refactor the weird while loop out of existence.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Darrick J. Wong 2019-11-07 12:29:00 -08:00
parent f755979355
commit 5113f8ec37
1 changed files with 65 additions and 52 deletions
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117
fs/xfs/libxfs/xfs_alloc.c
View File

@ -1464,6 +1464,64 @@ xfs_alloc_ag_vextent_locality(
return 0;
}
/* Check the last block of the cnt btree for allocations. */
static int
xfs_alloc_ag_vextent_lastblock(
struct xfs_alloc_arg *args,
struct xfs_alloc_cur *acur,
xfs_agblock_t *bno,
xfs_extlen_t *len,
bool *allocated)
{
int error;
int i;
#ifdef DEBUG
/* Randomly don't execute the first algorithm. */
if (prandom_u32() & 1)
return 0;
#endif
/*
* Start from the entry that lookup found, sequence through all larger
* free blocks. If we're actually pointing at a record smaller than
* maxlen, go to the start of this block, and skip all those smaller
* than minlen.
*/
if (len || args->alignment > 1) {
acur->cnt->bc_ptrs[0] = 1;
do {
error = xfs_alloc_get_rec(acur->cnt, bno, len, &i);
if (error)
return error;
XFS_WANT_CORRUPTED_RETURN(args->mp, i == 1);
if (*len >= args->minlen)
break;
error = xfs_btree_increment(acur->cnt, 0, &i);
if (error)
return error;
} while (i);
ASSERT(*len >= args->minlen);
if (!i)
return 0;
}
error = xfs_alloc_walk_iter(args, acur, acur->cnt, true, false, -1, &i);
if (error)
return error;
/*
* It didn't work. We COULD be in a case where there's a good record
* somewhere, so try again.
*/
if (acur->len == 0)
return 0;
trace_xfs_alloc_near_first(args);
*allocated = true;
return 0;
}
/*
* Allocate a variable extent near bno in the allocation group agno.
* Extent's length (returned in len) will be between minlen and maxlen,
@ -1479,14 +1537,6 @@ xfs_alloc_ag_vextent_near(
int i; /* result code, temporary */
xfs_agblock_t bno;
xfs_extlen_t len;
#ifdef DEBUG
/*
* Randomly don't execute the first algorithm.
*/
int dofirst; /* set to do first algorithm */
dofirst = prandom_u32() & 1;
#endif
/* handle uninitialized agbno range so caller doesn't have to */
if (!args->min_agbno && !args->max_agbno)
@ -1529,53 +1579,16 @@ restart:
* near the right edge of the tree. If it's in the last btree leaf
* block, then we just examine all the entries in that block
* that are big enough, and pick the best one.
* This is written as a while loop so we can break out of it,
* but we never loop back to the top.
*/
while (xfs_btree_islastblock(acur.cnt, 0)) {
#ifdef DEBUG
if (dofirst)
break;
#endif
/*
* Start from the entry that lookup found, sequence through
* all larger free blocks. If we're actually pointing at a
* record smaller than maxlen, go to the start of this block,
* and skip all those smaller than minlen.
*/
if (len || args->alignment > 1) {
acur.cnt->bc_ptrs[0] = 1;
do {
error = xfs_alloc_get_rec(acur.cnt, &bno, &len,
&i);
if (error)
goto out;
XFS_WANT_CORRUPTED_GOTO(args->mp, i == 1, out);
if (len >= args->minlen)
break;
error = xfs_btree_increment(acur.cnt, 0, &i);
if (error)
goto out;
} while (i);
ASSERT(len >= args->minlen);
if (!i)
break;
}
if (xfs_btree_islastblock(acur.cnt, 0)) {
bool allocated = false;
error = xfs_alloc_walk_iter(args, &acur, acur.cnt, true, false,
-1, &i);
error = xfs_alloc_ag_vextent_lastblock(args, &acur, &bno, &len,
&allocated);
if (error)
goto out;
/*
* It didn't work. We COULD be in a case where
* there's a good record somewhere, so try again.
*/
if (acur.len == 0)
break;
trace_xfs_alloc_near_first(args);
goto alloc;
if (allocated)
goto alloc_finish;
}
/*
@ -1601,7 +1614,7 @@ restart:
goto out;
}
alloc:
alloc_finish:
/* fix up btrees on a successful allocation */
error = xfs_alloc_cur_finish(args, &acur);