From: Christoph Hellwig Date: Mon, 9 Jan 2017 21:39:35 +0000 (-0800) Subject: xfs: don't rely on ->total in xfs_alloc_space_available X-Git-Tag: v4.10-rc4~22^2~2 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=12ef830198b0d71668eb9b59f9ba69d32951a48a;p=linux.git xfs: don't rely on ->total in xfs_alloc_space_available ->total is a bit of an odd parameter passed down to the low-level allocator all the way from the high-level callers. It's supposed to contain the maximum number of blocks to be allocated for the whole transaction [1]. But in xfs_iomap_write_allocate we only convert existing delayed allocations and thus only have a minimal block reservation for the current transaction, so xfs_alloc_space_available can't use it for the allocation decisions. Use the maximum of args->total and the calculated block requirement to make a decision. We probably should get rid of args->total eventually and instead apply ->minleft more broadly, but that will require some extensive changes all over. [1] which creates lots of confusion as most callers don't decrement it once doing a first allocation. But that's for a separate series. Signed-off-by: Christoph Hellwig Reviewed-by: Brian Foster Signed-off-by: Darrick J. Wong --- diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c index f2e7eb6e5243..9f06a211e157 100644 --- a/fs/xfs/libxfs/xfs_alloc.c +++ b/fs/xfs/libxfs/xfs_alloc.c @@ -1995,7 +1995,7 @@ xfs_alloc_space_available( int flags) { struct xfs_perag *pag = args->pag; - xfs_extlen_t longest; + xfs_extlen_t alloc_len, longest; xfs_extlen_t reservation; /* blocks that are still reserved */ int available; @@ -2005,15 +2005,16 @@ xfs_alloc_space_available( reservation = xfs_ag_resv_needed(pag, args->resv); /* do we have enough contiguous free space for the allocation? */ + alloc_len = args->minlen + (args->alignment - 1) + args->minalignslop; longest = xfs_alloc_longest_free_extent(args->mp, pag, min_free, reservation); - if ((args->minlen + args->alignment + args->minalignslop - 1) > longest) + if (longest < alloc_len) return false; /* do we have enough free space remaining for the allocation? */ available = (int)(pag->pagf_freeblks + pag->pagf_flcount - reservation - min_free - args->minleft); - if (available < (int)args->total) + if (available < (int)max(args->total, alloc_len)) return false; /*