xfs: hide log iovec alignment constraints

Source kernel commit: b2c28035cea290edbcec697504e5b7a4b1e023e7

Callers currently have to round out the size of buffers to match the
aligment constraints of log iovecs and xlog_write(). They should not
need to know this detail, so introduce a new function to calculate
the iovec length (for use in ->iop_size implementations). Also
modify xlog_finish_iovec() to round up the length to the correct
alignment so the callers don't need to do this, either.

Convert the only user - inode forks - of this alignment rounding to
use the new interface.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>

diff --git a/libxfs/xfs_inode_fork.c b/libxfs/xfs_inode_fork.c
index ac3692b5fcdb7a7aafca7bb766c5684389cc8df5..cf0dd52eb3c940a245cdf2c170a7c19968c1bb33 100644 (file)
--- a/libxfs/xfs_inode_fork.c
+++ b/libxfs/xfs_inode_fork.c
@@ -34,7 +34,7 @@ xfs_init_local_fork(
        int64_t                 size)
 {
        struct xfs_ifork        *ifp = XFS_IFORK_PTR(ip, whichfork);
-       int                     mem_size = size, real_size = 0;
+       int                     mem_size = size;
        bool                    zero_terminate;
 
        /*
@@ -48,13 +48,7 @@ xfs_init_local_fork(
                mem_size++;
 
        if (size) {
-               /*
-                * As we round up the allocation here, we need to ensure the
-                * bytes we don't copy data into are zeroed because the log
-                * vectors still copy them into the journal.
-                */
-               real_size = roundup(mem_size, 4);
-               ifp->if_u1.if_data = kmem_zalloc(real_size, KM_NOFS);
+               ifp->if_u1.if_data = kmem_alloc(mem_size, KM_NOFS);
                memcpy(ifp->if_u1.if_data, data, size);
                if (zero_terminate)
                        ifp->if_u1.if_data[size] = '\0';
@@ -500,14 +494,8 @@ xfs_idata_realloc(
                return;
        }
 
-       /*
-        * For inline data, the underlying buffer must be a multiple of 4 bytes
-        * in size so that it can be logged and stay on word boundaries.
-        * We enforce that here, and use __GFP_ZERO to ensure that size
-        * extensions always zero the unused roundup area.
-        */
-       ifp->if_u1.if_data = krealloc(ifp->if_u1.if_data, roundup(new_size, 4),
-                                     GFP_NOFS | __GFP_NOFAIL | __GFP_ZERO);
+       ifp->if_u1.if_data = krealloc(ifp->if_u1.if_data, new_size,
+                                     GFP_NOFS | __GFP_NOFAIL);
        ifp->if_bytes = new_size;
 }