On Mon, Jan 23, 2017 at 01:12:21PM -0800, Darrick J. Wong wrote:
> It's possible for the per-AG reservation initialization to return ENOSPC
> when fdblocks says there isn't free space. This is a valid state for
> the reservation tracker since subsequent extent freeing activity will
> simply be captured by the reservation mechanism, but if we subsequently
> retry a failed initialization, we need to undo the changes we made to
> ag_max_usable prior to recreating the reservation.
Hmm. I'd prefer to just not change any fields in __xfs_ag_resv_init
unless it succeeds. So far untested and un-changelogged patch below,
I'll kick off a test run soon:
diff --git a/fs/xfs/libxfs/xfs_ag_resv.c b/fs/xfs/libxfs/xfs_ag_resv.c
index 4773c1e..769d6e3 100644
--- a/fs/xfs/libxfs/xfs_ag_resv.c
+++ b/fs/xfs/libxfs/xfs_ag_resv.c
@@ -201,22 +201,27 @@ __xfs_ag_resv_init(
struct xfs_mount *mp = pag->pag_mount;
struct xfs_ag_resv *resv;
int error;
+ xfs_extlen_t reserved;
- resv = xfs_perag_resv(pag, type);
if (used > ask)
ask = used;
- resv->ar_asked = ask;
- resv->ar_reserved = resv->ar_orig_reserved = ask - used;
- mp->m_ag_max_usable -= ask;
-
- trace_xfs_ag_resv_init(pag, type, ask);
+ reserved = ask - used;
- error = xfs_mod_fdblocks(mp, -(int64_t)resv->ar_reserved, true);
- if (error)
+ error = xfs_mod_fdblocks(mp, -(int64_t)reserved, true);
+ if (error) {
trace_xfs_ag_resv_init_error(pag->pag_mount, pag->pag_agno,
error, _RET_IP_);
+ return error;
+ }
- return error;
+ mp->m_ag_max_usable -= ask;
+
+ resv = xfs_perag_resv(pag, type);
+ resv->ar_asked = ask;
+ resv->ar_reserved = resv->ar_orig_reserved = reserved;
+
+ trace_xfs_ag_resv_init(pag, type, ask);
+ return 0;
}
/* Create a per-AG block reservation. */
--
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