xfs: try any AG when allocating the first btree block when reflinking

Source kernel commit: 2fcc319d2467a5f5b78f35f79fd6e22741a31b1e

When a reflink operation causes the bmap code to allocate a btree block
we're currently doing single-AG allocations due to having ->firstblock
set and then try any higher AG due a little reflink quirk we've put in
when adding the reflink code.  But given that we do not have a minleft
reservation of any kind in this AG we can still not have any space in
the same or higher AG even if the file system has enough free space.
To fix this use a XFS_ALLOCTYPE_FIRST_AG allocation in this fall back
path instead.

[And yes, we need to redo this properly instead of piling hacks over
hacks.  I'm working on that, but it's not going to be a small series.
In the meantime this fixes the customer reported issue]

Also add a warning for failing allocations to make it easier to debug.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>

diff --git a/libxfs/libxfs_priv.h b/libxfs/libxfs_priv.h
index 839150088098d39649c9dd3680e6635403767da3..c2d4494b6e09f8a16374426c5604f22782778284 100644 (file)
--- a/libxfs/libxfs_priv.h
+++ b/libxfs/libxfs_priv.h
@@ -175,7 +175,10 @@ enum ce { CE_DEBUG, CE_CONT, CE_NOTE, CE_WARN, CE_ALERT, CE_PANIC };
 #define unlikely(x)            (x)
 #define rcu_read_lock()                ((void) 0)
 #define rcu_read_unlock()      ((void) 0)
-#define WARN_ON_ONCE(expr)     ((void) 0)
+/* Need to be able to handle this bare or in control flow */
+static inline bool WARN_ON_ONCE(bool expr) {
+       return (expr);
+}
 
 #define percpu_counter_read(x)         (*x)
 #define percpu_counter_read_positive(x)        ((*x) > 0 ? (*x) : 0)

diff --git a/libxfs/xfs_bmap.c b/libxfs/xfs_bmap.c
index 4b825f5b4d5ed0f1f5295b8736816e8de0991e50..482eda7da117c3ffce99c423b81ebf51be985c97 100644 (file)
--- a/libxfs/xfs_bmap.c
+++ b/libxfs/xfs_bmap.c
@@ -754,8 +754,8 @@ xfs_bmap_extents_to_btree(
                args.type = XFS_ALLOCTYPE_START_BNO;
                args.fsbno = XFS_INO_TO_FSB(mp, ip->i_ino);
        } else if (dfops->dop_low) {
-try_another_ag:
                args.type = XFS_ALLOCTYPE_START_BNO;
+try_another_ag:
                args.fsbno = *firstblock;
        } else {
                args.type = XFS_ALLOCTYPE_NEAR_BNO;
@@ -781,13 +781,17 @@ try_another_ag:
        if (xfs_sb_version_hasreflink(&cur->bc_mp->m_sb) &&
            args.fsbno == NULLFSBLOCK &&
            args.type == XFS_ALLOCTYPE_NEAR_BNO) {
-               dfops->dop_low = true;
+               args.type = XFS_ALLOCTYPE_FIRST_AG;
                goto try_another_ag;
        }
+       if (WARN_ON_ONCE(args.fsbno == NULLFSBLOCK)) {
+               xfs_iroot_realloc(ip, -1, whichfork);
+               xfs_btree_del_cursor(cur, XFS_BTREE_ERROR);
+               return -ENOSPC;
+       }
        /*
         * Allocation can't fail, the space was reserved.
         */
-       ASSERT(args.fsbno != NULLFSBLOCK);
        ASSERT(*firstblock == NULLFSBLOCK ||
               args.agno >= XFS_FSB_TO_AGNO(mp, *firstblock));
        *firstblock = cur->bc_private.b.firstblock = args.fsbno;

diff --git a/libxfs/xfs_bmap_btree.c b/libxfs/xfs_bmap_btree.c
index 00576e29b9ea445ba37aab43d8777664e85185a4..34017b2e102d512c9724782e151cf51c11643ab3 100644 (file)
--- a/libxfs/xfs_bmap_btree.c
+++ b/libxfs/xfs_bmap_btree.c
@@ -444,8 +444,8 @@ xfs_bmbt_alloc_block(
 
        if (args.fsbno == NULLFSBLOCK) {
                args.fsbno = be64_to_cpu(start->l);
-try_another_ag:
                args.type = XFS_ALLOCTYPE_START_BNO;
+try_another_ag:
                /*
                 * Make sure there is sufficient room left in the AG to
                 * complete a full tree split for an extent insert.  If
@@ -485,8 +485,8 @@ try_another_ag:
        if (xfs_sb_version_hasreflink(&cur->bc_mp->m_sb) &&
            args.fsbno == NULLFSBLOCK &&
            args.type == XFS_ALLOCTYPE_NEAR_BNO) {
-               cur->bc_private.b.dfops->dop_low = true;
                args.fsbno = cur->bc_private.b.firstblock;
+               args.type = XFS_ALLOCTYPE_FIRST_AG;
                goto try_another_ag;
        }
 
@@ -503,7 +503,7 @@ try_another_ag:
                        goto error0;
                cur->bc_private.b.dfops->dop_low = true;
        }
-       if (args.fsbno == NULLFSBLOCK) {
+       if (WARN_ON_ONCE(args.fsbno == NULLFSBLOCK)) {
                XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
                *stat = 0;
                return 0;