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xfs: factor out free space extent length check

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The longest extent length checks in xfs_alloc_fix_freelist() are now
essentially identical. Factor them out into a helper function, so we
know they are checking exactly the same thing before and after we
lock the AGF.

Signed-off-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:
Dave Chinner 2015-06-22 10:04:42 +10:00 committed by Dave Chinner
parent 50adbcb4c4
commit 72d552854b
1 changed files with 44 additions and 27 deletions
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71
fs/xfs/libxfs/xfs_alloc.c
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@ -1838,6 +1838,39 @@ xfs_alloc_longest_free_extent(
return pag->pagf_flcount > 0 || pag->pagf_longest > 0;
}
/*
* Check if the operation we are fixing up the freelist for should go ahead or
* not. If we are freeing blocks, we always allow it, otherwise the allocation
* is dependent on whether the size and shape of free space available will
* permit the requested allocation to take place.
*/
static bool
xfs_alloc_space_available(
struct xfs_alloc_arg *args,
xfs_extlen_t min_free,
int flags)
{
struct xfs_perag *pag = args->pag;
xfs_extlen_t longest;
int available;
if (flags & XFS_ALLOC_FLAG_FREEING)
return true;
/* do we have enough contiguous free space for the allocation? */
longest = xfs_alloc_longest_free_extent(args->mp, pag, min_free);
if ((args->minlen + args->alignment + args->minalignslop - 1) > longest)
return false;
/* do have enough free space remaining for the allocation? */
available = (int)(pag->pagf_freeblks + pag->pagf_flcount -
min_free - args->total);
if (available < (int)args->minleft)
return false;
return true;
}
/*
* Decide whether to use this allocation group for this allocation.
* If so, fix up the btree freelist's size.
@ -1851,7 +1884,6 @@ xfs_alloc_fix_freelist(
xfs_buf_t *agflbp;/* agfl buffer pointer */
xfs_agblock_t bno; /* freelist block */
int error; /* error result code */
xfs_extlen_t longest;/* longest extent in allocation group */
xfs_mount_t *mp; /* file system mount point structure */
xfs_extlen_t need; /* total blocks needed in freelist */
xfs_perag_t *pag; /* per-ag information structure */
@ -1887,22 +1919,12 @@ xfs_alloc_fix_freelist(
return 0;
}
if (!(flags & XFS_ALLOC_FLAG_FREEING)) {
/*
* If it looks like there isn't a long enough extent, or enough
* total blocks, reject it.
*/
need = XFS_MIN_FREELIST_PAG(pag, mp);
longest = xfs_alloc_longest_free_extent(mp, pag, need);
if ((args->minlen + args->alignment + args->minalignslop - 1) >
longest ||
((int)(pag->pagf_freeblks + pag->pagf_flcount -
need - args->total) < (int)args->minleft)) {
if (agbp)
xfs_trans_brelse(tp, agbp);
args->agbp = NULL;
return 0;
}
need = XFS_MIN_FREELIST_PAG(pag, mp);
if (!xfs_alloc_space_available(args, need, flags)) {
if (agbp)
xfs_trans_brelse(tp, agbp);
args->agbp = NULL;
return 0;
}
/*
@ -1924,17 +1946,12 @@ xfs_alloc_fix_freelist(
/* If there isn't enough total space or single-extent, reject it. */
need = XFS_MIN_FREELIST_PAG(pag, mp);
if (!(flags & XFS_ALLOC_FLAG_FREEING)) {
longest = xfs_alloc_longest_free_extent(mp, pag, need);
if ((args->minlen + args->alignment + args->minalignslop - 1) >
longest ||
((int)(pag->pagf_freeblks + pag->pagf_flcount -
need - args->total) < (int)args->minleft)) {
xfs_trans_brelse(tp, agbp);
args->agbp = NULL;
return 0;
}
if (!xfs_alloc_space_available(args, need, flags)) {
xfs_trans_brelse(tp, agbp);
args->agbp = NULL;
return 0;
}
/*
* Make the freelist shorter if it's too long.
*