xfs: remove if_real_bytes

The field is only used for asserts, and to track if we really need to do
realloc when growing the inode fork data.  But the krealloc function
already performs this check internally, so there is no need to keep track
of the real allocation size.

This will free space in the inode fork for keeping a sequence counter of
changes to the extent list.

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>

4 files changed, 5 insertions, 22 deletions

diff --git a/fs/xfs/libxfs/xfs_inode_fork.c b/fs/xfs/libxfs/xfs_inode_fork.c
index 183ec0cb8921..dee85b0f8846 100644
--- a/fs/xfs/libxfs/xfs_inode_fork.c
+++ b/fs/xfs/libxfs/xfs_inode_fork.c
@@ -158,7 +158,6 @@ xfs_init_local_fork(
         }
 
         ifp->if_bytes = size;
-        ifp->if_real_bytes = real_size;
         ifp->if_flags &= ~(XFS_IFEXTENTS | XFS_IFBROOT);
         ifp->if_flags |= XFS_IFINLINE;
 }
@@ -226,7 +225,6 @@ xfs_iformat_extents(
                 return -EFSCORRUPTED;
         }
 
-        ifp->if_real_bytes = 0;
         ifp->if_bytes = 0;
         ifp->if_u1.if_root = NULL;
         ifp->if_height = 0;
@@ -317,7 +315,6 @@ xfs_iformat_btree(
         ifp->if_flags &= ~XFS_IFEXTENTS;
         ifp->if_flags |= XFS_IFBROOT;
 
-        ifp->if_real_bytes = 0;
         ifp->if_bytes = 0;
         ifp->if_u1.if_root = NULL;
         ifp->if_height = 0;
@@ -501,7 +498,6 @@ xfs_idata_realloc(
                  */
                 real_size = roundup(new_size, 4);
                 if (ifp->if_u1.if_data == NULL) {
-                        ASSERT(ifp->if_real_bytes == 0);
                         ifp->if_u1.if_data = kmem_alloc(real_size,
                                                         KM_SLEEP | KM_NOFS);
                 } else {
@@ -509,15 +505,12 @@ xfs_idata_realloc(
                          * Only do the realloc if the underlying size
                          * is really changing.
                          */
-                        if (ifp->if_real_bytes != real_size) {
-                                ifp->if_u1.if_data =
-                                        kmem_realloc(ifp->if_u1.if_data,
-                                                        real_size,
-                                                        KM_SLEEP | KM_NOFS);
-                        }
+                        ifp->if_u1.if_data =
+                                kmem_realloc(ifp->if_u1.if_data,
+                                                real_size,
+                                                KM_SLEEP | KM_NOFS);
                 }
         }
-        ifp->if_real_bytes = real_size;
         ifp->if_bytes = new_size;
         ASSERT(ifp->if_bytes <= XFS_IFORK_SIZE(ip, whichfork));
 }
@@ -543,17 +536,13 @@ xfs_idestroy_fork(
          */
         if (XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_LOCAL) {
                 if (ifp->if_u1.if_data != NULL) {
-                        ASSERT(ifp->if_real_bytes != 0);
                         kmem_free(ifp->if_u1.if_data);
                         ifp->if_u1.if_data = NULL;
-                        ifp->if_real_bytes = 0;
                 }
         } else if ((ifp->if_flags & XFS_IFEXTENTS) && ifp->if_height) {
                 xfs_iext_destroy(ifp);
         }
 
-        ASSERT(ifp->if_real_bytes == 0);
-
         if (whichfork == XFS_ATTR_FORK) {
                 kmem_zone_free(xfs_ifork_zone, ip->i_afp);
                 ip->i_afp = NULL;
diff --git a/fs/xfs/libxfs/xfs_inode_fork.h b/fs/xfs/libxfs/xfs_inode_fork.h
index 781b1603df5e..46242052aad0 100644
--- a/fs/xfs/libxfs/xfs_inode_fork.h
+++ b/fs/xfs/libxfs/xfs_inode_fork.h
@@ -14,7 +14,6 @@ struct xfs_dinode;
  */
 typedef struct xfs_ifork {
         int                     if_bytes;       /* bytes in if_u1 */
-        int                     if_real_bytes;  /* bytes allocated in if_u1 */
         struct xfs_btree_block  *if_broot;      /* file's incore btree root */
         short                   if_broot_bytes; /* bytes allocated for root */
         unsigned char           if_flags;       /* per-fork flags */
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 64c694d2b2a5..54fcfdfc748c 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -927,7 +927,7 @@ xfs_ialloc(
         case S_IFLNK:
                 ip->i_d.di_format = XFS_DINODE_FMT_EXTENTS;
                 ip->i_df.if_flags = XFS_IFEXTENTS;
-                ip->i_df.if_bytes = ip->i_df.if_real_bytes = 0;
+                ip->i_df.if_bytes = 0;
                 ip->i_df.if_u1.if_root = NULL;
                 break;
         default:
@@ -1841,7 +1841,6 @@ xfs_inactive(
          * to clean up here.
          */
         if (VFS_I(ip)->i_mode == 0) {
-                ASSERT(ip->i_df.if_real_bytes == 0);
                 ASSERT(ip->i_df.if_broot_bytes == 0);
                 return;
         }
diff --git a/fs/xfs/xfs_inode_item.c b/fs/xfs/xfs_inode_item.c
index 2389c34c172d..fa1c4fe2ffbf 100644
--- a/fs/xfs/xfs_inode_item.c
+++ b/fs/xfs/xfs_inode_item.c
@@ -194,8 +194,6 @@ xfs_inode_item_format_data_fork(
                          * to be there by xfs_idata_realloc().
                          */
                         data_bytes = roundup(ip->i_df.if_bytes, 4);
-                        ASSERT(ip->i_df.if_real_bytes == 0 ||
-                               ip->i_df.if_real_bytes >= data_bytes);
                         ASSERT(ip->i_df.if_u1.if_data != NULL);
                         ASSERT(ip->i_d.di_size > 0);
                         xlog_copy_iovec(lv, vecp, XLOG_REG_TYPE_ILOCAL,
@@ -280,8 +278,6 @@ xfs_inode_item_format_attr_fork(
                          * to be there by xfs_idata_realloc().
                          */
                         data_bytes = roundup(ip->i_afp->if_bytes, 4);
-                        ASSERT(ip->i_afp->if_real_bytes == 0 ||
-                               ip->i_afp->if_real_bytes >= data_bytes);
                         ASSERT(ip->i_afp->if_u1.if_data != NULL);
                         xlog_copy_iovec(lv, vecp, XLOG_REG_TYPE_IATTR_LOCAL,
                                         ip->i_afp->if_u1.if_data,