xfs: xfs_defer_capture should absorb remaining block reservations

commit 4f9a60c48078c0efa3459678fa8d6e050e8ada5d upstream.

When xfs_defer_capture extracts the deferred ops and transaction state
from a transaction, it should record the remaining block reservations so
that when we continue the dfops chain, we can reserve the same number of
blocks to use.  We capture the reservations for both data and realtime
volumes.

This adds the requirement that every log intent item recovery function
must be careful to reserve enough blocks to handle both itself and all
defer ops that it can queue.  On the other hand, this enables us to do
away with the handwaving block estimation nonsense that was going on in
xlog_finish_defer_ops.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Chandan Babu R <chandan.babu@oracle.com>
Acked-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/xfs/libxfs/xfs_defer.c b/fs/xfs/libxfs/xfs_defer.c
index 0448197d3b712573091e584193be7d865c068e1c..4c36ab9dd33e82a053dc2afa3439fa9807d548d2 100644 (file)
--- a/fs/xfs/libxfs/xfs_defer.c
+++ b/fs/xfs/libxfs/xfs_defer.c
@@ -589,6 +589,10 @@ xfs_defer_ops_capture(
        dfc->dfc_tpflags = tp->t_flags & XFS_TRANS_LOWMODE;
        tp->t_flags &= ~XFS_TRANS_LOWMODE;
 
+       /* Capture the remaining block reservations along with the dfops. */
+       dfc->dfc_blkres = tp->t_blk_res - tp->t_blk_res_used;
+       dfc->dfc_rtxres = tp->t_rtx_res - tp->t_rtx_res_used;
+
        return dfc;
 }
 

diff --git a/fs/xfs/libxfs/xfs_defer.h b/fs/xfs/libxfs/xfs_defer.h
index 2c27f439298d7783f8d3ea3ef1d069beb9fcf54c..7b0794ad58ca3c178db94c62a71b07faf197bbc3 100644 (file)
--- a/fs/xfs/libxfs/xfs_defer.h
+++ b/fs/xfs/libxfs/xfs_defer.h
@@ -73,6 +73,10 @@ struct xfs_defer_capture {
        /* Deferred ops state saved from the transaction. */
        struct list_head        dfc_dfops;
        unsigned int            dfc_tpflags;
+
+       /* Block reservations for the data and rt devices. */
+       unsigned int            dfc_blkres;
+       unsigned int            dfc_rtxres;
 };
 
 /*

diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
index 388a2ec2d8796b35004d520badc28fbd585b5e0c..a591420a2c895078eb7779ee9563327556d706d9 100644 (file)
--- a/fs/xfs/xfs_log_recover.c
+++ b/fs/xfs/xfs_log_recover.c
@@ -4766,27 +4766,12 @@ xlog_finish_defer_ops(
 {
        struct xfs_defer_capture *dfc, *next;
        struct xfs_trans        *tp;
-       int64_t                 freeblks;
-       uint64_t                resblks;
        int                     error = 0;
 
        list_for_each_entry_safe(dfc, next, capture_list, dfc_list) {
-               /*
-                * We're finishing the defer_ops that accumulated as a result
-                * of recovering unfinished intent items during log recovery.
-                * We reserve an itruncate transaction because it is the
-                * largest permanent transaction type.  Since we're the only
-                * user of the fs right now, take 93% (15/16) of the available
-                * free blocks.  Use weird math to avoid a 64-bit division.
-                */
-               freeblks = percpu_counter_sum(&mp->m_fdblocks);
-               if (freeblks <= 0)
-                       return -ENOSPC;
-
-               resblks = min_t(uint64_t, UINT_MAX, freeblks);
-               resblks = (resblks * 15) >> 4;
-               error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate, resblks,
-                               0, XFS_TRANS_RESERVE, &tp);
+               error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate,
+                               dfc->dfc_blkres, dfc->dfc_rtxres,
+                               XFS_TRANS_RESERVE, &tp);
                if (error)
                        return error;