xfs: remove the i_size field in struct xfs_inode

There is no fundamental need to keep an in-memory inode size copy in the XFS
inode.  We already have the on-disk value in the dinode, and the separate
in-memory copy that we need for regular files only in the XFS inode.

Remove the xfs_inode i_size field and change the XFS_ISIZE macro to use the
VFS inode i_size field for regular files.  Switch code that was directly
accessing the i_size field in the xfs_inode to XFS_ISIZE, or in cases where
we are limited to regular files direct access of the VFS inode i_size field.

This also allows dropping some fairly complicated code in the write path
which dealt with keeping the xfs_inode i_size uptodate with the VFS i_size
that is getting updated inside ->write_end.

Note that we do not bother resetting the VFS i_size when truncating a file
that gets freed to zero as there is no point in doing so because the VFS inode
is no longer in use at this point.  Just relax the assert in xfs_ifree to
only check the on-disk size instead.

Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ben Myers <bpm@sgi.com>

12 files changed, 56 insertions, 82 deletions

diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 574d4ee9b62..4d27ea117e0 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -111,7 +111,7 @@ xfs_ioend_new_eof(
         xfs_fsize_t             bsize;
 
         bsize = ioend->io_offset + ioend->io_size;
-        isize = MAX(ip->i_size, ip->i_new_size);
+        isize = MAX(i_size_read(VFS_I(ip)), ip->i_new_size);
         isize = MIN(isize, bsize);
         return isize > ip->i_d.di_size ? isize : 0;
 }
diff --git a/fs/xfs/xfs_bmap.c b/fs/xfs/xfs_bmap.c
index 7a888ca2f7f..188ef2fbd62 100644
--- a/fs/xfs/xfs_bmap.c
+++ b/fs/xfs/xfs_bmap.c
@@ -3997,11 +3997,8 @@ xfs_bmap_one_block(
         xfs_bmbt_irec_t s;              /* internal version of extent */
 
 #ifndef DEBUG
-        if (whichfork == XFS_DATA_FORK) {
-                return S_ISREG(ip->i_d.di_mode) ?
-                        (ip->i_size == ip->i_mount->m_sb.sb_blocksize) :
-                        (ip->i_d.di_size == ip->i_mount->m_sb.sb_blocksize);
-        }
+        if (whichfork == XFS_DATA_FORK)
+                return XFS_ISIZE(ip) == ip->i_mount->m_sb.sb_blocksize;
 #endif  /* !DEBUG */
         if (XFS_IFORK_NEXTENTS(ip, whichfork) != 1)
                 return 0;
@@ -4013,7 +4010,7 @@ xfs_bmap_one_block(
         xfs_bmbt_get_all(ep, &s);
         rval = s.br_startoff == 0 && s.br_blockcount == 1;
         if (rval && whichfork == XFS_DATA_FORK)
-                ASSERT(ip->i_size == ip->i_mount->m_sb.sb_blocksize);
+                ASSERT(XFS_ISIZE(ip) == ip->i_mount->m_sb.sb_blocksize);
         return rval;
 }
 
@@ -5427,7 +5424,7 @@ xfs_getbmapx_fix_eof_hole(
         if (startblock == HOLESTARTBLOCK) {
                 mp = ip->i_mount;
                 out->bmv_block = -1;
-                fixlen = XFS_FSB_TO_BB(mp, XFS_B_TO_FSB(mp, ip->i_size));
+                fixlen = XFS_FSB_TO_BB(mp, XFS_B_TO_FSB(mp, XFS_ISIZE(ip)));
                 fixlen -= out->bmv_offset;
                 if (prealloced && out->bmv_offset + out->bmv_length == end) {
                         /* Came to hole at EOF. Trim it. */
@@ -5515,7 +5512,7 @@ xfs_getbmap(
                         fixlen = XFS_MAXIOFFSET(mp);
                 } else {
                         prealloced = 0;
-                        fixlen = ip->i_size;
+                        fixlen = XFS_ISIZE(ip);
                 }
         }
 
@@ -5544,7 +5541,7 @@ xfs_getbmap(
 
         xfs_ilock(ip, XFS_IOLOCK_SHARED);
         if (whichfork == XFS_DATA_FORK && !(iflags & BMV_IF_DELALLOC)) {
-                if (ip->i_delayed_blks || ip->i_size > ip->i_d.di_size) {
+                if (ip->i_delayed_blks || XFS_ISIZE(ip) > ip->i_d.di_size) {
                         error = xfs_flush_pages(ip, 0, -1, 0, FI_REMAPF);
                         if (error)
                                 goto out_unlock_iolock;
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index f675f3d9d7b..86d5dc26046 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -327,7 +327,7 @@ xfs_file_aio_read(
                                 mp->m_rtdev_targp : mp->m_ddev_targp;
                 if ((iocb->ki_pos & target->bt_smask) ||
                     (size & target->bt_smask)) {
-                        if (iocb->ki_pos == ip->i_size)
+                        if (iocb->ki_pos == i_size_read(inode))
                                 return 0;
                         return -XFS_ERROR(EINVAL);
                 }
@@ -412,30 +412,6 @@ xfs_file_splice_read(
         return ret;
 }
 
-STATIC void
-xfs_aio_write_isize_update(
-        struct inode    *inode,
-        loff_t          *ppos,
-        ssize_t         bytes_written)
-{
-        struct xfs_inode        *ip = XFS_I(inode);
-        xfs_fsize_t             isize = i_size_read(inode);
-
-        if (bytes_written > 0)
-                XFS_STATS_ADD(xs_write_bytes, bytes_written);
-
-        if (unlikely(bytes_written < 0 && bytes_written != -EFAULT &&
-                                        *ppos > isize))
-                *ppos = isize;
-
-        if (*ppos > ip->i_size) {
-                xfs_rw_ilock(ip, XFS_ILOCK_EXCL);
-                if (*ppos > ip->i_size)
-                        ip->i_size = *ppos;
-                xfs_rw_iunlock(ip, XFS_ILOCK_EXCL);
-        }
-}
-
 /*
  * If this was a direct or synchronous I/O that failed (such as ENOSPC) then
  * part of the I/O may have been written to disk before the error occurred.  In
@@ -451,8 +427,8 @@ xfs_aio_write_newsize_update(
                 xfs_rw_ilock(ip, XFS_ILOCK_EXCL);
                 if (new_size == ip->i_new_size)
                         ip->i_new_size = 0;
-                if (ip->i_d.di_size > ip->i_size)
-                        ip->i_d.di_size = ip->i_size;
+                if (ip->i_d.di_size > i_size_read(VFS_I(ip)))
+                        ip->i_d.di_size = i_size_read(VFS_I(ip));
                 xfs_rw_iunlock(ip, XFS_ILOCK_EXCL);
         }
 }
@@ -492,15 +468,16 @@ xfs_file_splice_write(
         new_size = *ppos + count;
 
         xfs_ilock(ip, XFS_ILOCK_EXCL);
-        if (new_size > ip->i_size)
+        if (new_size > i_size_read(inode))
                 ip->i_new_size = new_size;
         xfs_iunlock(ip, XFS_ILOCK_EXCL);
 
         trace_xfs_file_splice_write(ip, count, *ppos, ioflags);
 
         ret = generic_file_splice_write(pipe, outfilp, ppos, count, flags);
+        if (ret > 0)
+                XFS_STATS_ADD(xs_write_bytes, ret);
 
-        xfs_aio_write_isize_update(inode, ppos, ret);
         xfs_aio_write_newsize_update(ip, new_size);
         xfs_iunlock(ip, XFS_IOLOCK_EXCL);
         return ret;
@@ -728,14 +705,14 @@ restart:
          * values are still valid.
          */
         if ((ip->i_new_size && *pos > ip->i_new_size) ||
-            (!ip->i_new_size && *pos > ip->i_size)) {
+            (!ip->i_new_size && *pos > i_size_read(inode))) {
                 if (*iolock == XFS_IOLOCK_SHARED) {
                         xfs_rw_iunlock(ip, XFS_ILOCK_EXCL | *iolock);
                         *iolock = XFS_IOLOCK_EXCL;
                         xfs_rw_ilock(ip, XFS_ILOCK_EXCL | *iolock);
                         goto restart;
                 }
-                error = -xfs_zero_eof(ip, *pos, ip->i_size);
+                error = -xfs_zero_eof(ip, *pos, i_size_read(inode));
         }
 
         /*
@@ -744,7 +721,7 @@ restart:
          * ip->i_new_size if this IO ends beyond any other in-flight writes.
          */
         new_size = *pos + *count;
-        if (new_size > ip->i_size) {
+        if (new_size > i_size_read(inode)) {
                 if (new_size > ip->i_new_size)
                         ip->i_new_size = new_size;
                 *new_sizep = new_size;
@@ -957,11 +934,11 @@ xfs_file_aio_write(
                 ret = xfs_file_buffered_aio_write(iocb, iovp, nr_segs, pos,
                                                 ocount, &new_size, &iolock);
 
-        xfs_aio_write_isize_update(inode, &iocb->ki_pos, ret);
-
         if (ret <= 0)
                 goto out_unlock;
 
+        XFS_STATS_ADD(xs_write_bytes, ret);
+
         /* Handle various SYNC-type writes */
         if ((file->f_flags & O_DSYNC) || IS_SYNC(inode)) {
                 loff_t end = pos + ret - 1;
diff --git a/fs/xfs/xfs_fs_subr.c b/fs/xfs/xfs_fs_subr.c
index ed88ed16811..652b875a9d4 100644
--- a/fs/xfs/xfs_fs_subr.c
+++ b/fs/xfs/xfs_fs_subr.c
@@ -90,7 +90,7 @@ xfs_wait_on_pages(
 
         if (mapping_tagged(mapping, PAGECACHE_TAG_WRITEBACK)) {
                 return -filemap_fdatawait_range(mapping, first,
-                                        last == -1 ? ip->i_size - 1 : last);
+                                        last == -1 ? XFS_ISIZE(ip) - 1 : last);
         }
         return 0;
 }
diff --git a/fs/xfs/xfs_iget.c b/fs/xfs/xfs_iget.c
index a7cf7139f9a..3b5b78aa3b8 100644
--- a/fs/xfs/xfs_iget.c
+++ b/fs/xfs/xfs_iget.c
@@ -94,7 +94,6 @@ xfs_inode_alloc(
         ip->i_update_core = 0;
         ip->i_delayed_blks = 0;
         memset(&ip->i_d, 0, sizeof(xfs_icdinode_t));
-        ip->i_size = 0;
         ip->i_new_size = 0;
 
         return ip;
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 62603369b52..b21022499c2 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -347,7 +347,6 @@ xfs_iformat(
                         return XFS_ERROR(EFSCORRUPTED);
                 }
                 ip->i_d.di_size = 0;
-                ip->i_size = 0;
                 ip->i_df.if_u2.if_rdev = xfs_dinode_get_rdev(dip);
                 break;
 
@@ -853,7 +852,6 @@ xfs_iread(
         }
 
         ip->i_delayed_blks = 0;
-        ip->i_size = ip->i_d.di_size;
 
         /*
          * Mark the buffer containing the inode as something to keep
@@ -1043,7 +1041,6 @@ xfs_ialloc(
         }
 
         ip->i_d.di_size = 0;
-        ip->i_size = 0;
         ip->i_d.di_nextents = 0;
         ASSERT(ip->i_d.di_nblocks == 0);
 
@@ -1198,7 +1195,7 @@ xfs_itruncate_extents(
         int                     done = 0;
 
         ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL|XFS_IOLOCK_EXCL));
-        ASSERT(new_size <= ip->i_size);
+        ASSERT(new_size <= XFS_ISIZE(ip));
         ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
         ASSERT(ip->i_itemp != NULL);
         ASSERT(ip->i_itemp->ili_lock_flags == 0);
@@ -1712,8 +1709,7 @@ xfs_ifree(
         ASSERT(ip->i_d.di_nlink == 0);
         ASSERT(ip->i_d.di_nextents == 0);
         ASSERT(ip->i_d.di_anextents == 0);
-        ASSERT((ip->i_d.di_size == 0 && ip->i_size == 0) ||
-               (!S_ISREG(ip->i_d.di_mode)));
+        ASSERT(ip->i_d.di_size == 0 || !S_ISREG(ip->i_d.di_mode));
         ASSERT(ip->i_d.di_nblocks == 0);
 
         /*
diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index 4acbe740be4..cd99e43fa8f 100644
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h
@@ -246,16 +246,12 @@ typedef struct xfs_inode {
 
         xfs_icdinode_t          i_d;            /* most of ondisk inode */
 
-        xfs_fsize_t             i_size;         /* in-memory size */
         xfs_fsize_t             i_new_size;     /* size when write completes */
 
         /* VFS inode */
         struct inode            i_vnode;        /* embedded VFS inode */
 } xfs_inode_t;
 
-#define XFS_ISIZE(ip)   S_ISREG((ip)->i_d.di_mode) ? \
-                                (ip)->i_size : (ip)->i_d.di_size;
-
 /* Convert from vfs inode to xfs inode */
 static inline struct xfs_inode *XFS_I(struct inode *inode)
 {
@@ -269,6 +265,18 @@ static inline struct inode *VFS_I(struct xfs_inode *ip)
 }
 
 /*
+ * For regular files we only update the on-disk filesize when actually
+ * writing data back to disk.  Until then only the copy in the VFS inode
+ * is uptodate.
+ */
+static inline xfs_fsize_t XFS_ISIZE(struct xfs_inode *ip)
+{
+        if (S_ISREG(ip->i_d.di_mode))
+                return i_size_read(VFS_I(ip));
+        return ip->i_d.di_size;
+}
+
+/*
  * i_flags helper functions
  */
 static inline void
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index a27a44659da..246c7d57c6f 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -74,7 +74,7 @@ xfs_iomap_eof_align_last_fsb(
                 else if (mp->m_dalign)
                         align = mp->m_dalign;
 
-                if (align && ip->i_size >= XFS_FSB_TO_B(mp, align))
+                if (align && XFS_ISIZE(ip) >= XFS_FSB_TO_B(mp, align))
                         new_last_fsb = roundup_64(*last_fsb, align);
         }
 
@@ -154,7 +154,7 @@ xfs_iomap_write_direct(
 
         offset_fsb = XFS_B_TO_FSBT(mp, offset);
         last_fsb = XFS_B_TO_FSB(mp, ((xfs_ufsize_t)(offset + count)));
-        if ((offset + count) > ip->i_size) {
+        if ((offset + count) > XFS_ISIZE(ip)) {
                 error = xfs_iomap_eof_align_last_fsb(mp, ip, extsz, &last_fsb);
                 if (error)
                         goto error_out;
@@ -211,7 +211,7 @@ xfs_iomap_write_direct(
         xfs_trans_ijoin(tp, ip, 0);
 
         bmapi_flag = 0;
-        if (offset < ip->i_size || extsz)
+        if (offset < XFS_ISIZE(ip) || extsz)
                 bmapi_flag |= XFS_BMAPI_PREALLOC;
 
         /*
@@ -286,7 +286,7 @@ xfs_iomap_eof_want_preallocate(
         int             found_delalloc = 0;
 
         *prealloc = 0;
-        if ((offset + count) <= ip->i_size)
+        if (offset + count <= XFS_ISIZE(ip))
                 return 0;
 
         /*
@@ -340,7 +340,7 @@ xfs_iomap_prealloc_size(
                  * if we pass in alloc_blocks = 0. Hence the "+ 1" to
                  * ensure we always pass in a non-zero value.
                  */
-                alloc_blocks = XFS_B_TO_FSB(mp, ip->i_size) + 1;
+                alloc_blocks = XFS_B_TO_FSB(mp, XFS_ISIZE(ip)) + 1;
                 alloc_blocks = XFS_FILEOFF_MIN(MAXEXTLEN,
                                         rounddown_pow_of_two(alloc_blocks));
 
@@ -564,7 +564,7 @@ xfs_iomap_write_allocate(
                          * back....
                          */
                         nimaps = 1;
-                        end_fsb = XFS_B_TO_FSB(mp, ip->i_size);
+                        end_fsb = XFS_B_TO_FSB(mp, XFS_ISIZE(ip));
                         error = xfs_bmap_last_offset(NULL, ip, &last_block,
                                                         XFS_DATA_FORK);
                         if (error)
diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index f02eaa298d3..ab302539e5b 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -778,7 +778,7 @@ xfs_setattr_size(
                 lock_flags |= XFS_IOLOCK_EXCL;
         xfs_ilock(ip, lock_flags);
 
-        oldsize = ip->i_size;
+        oldsize = inode->i_size;
         newsize = iattr->ia_size;
 
         /*
@@ -897,7 +897,6 @@ xfs_setattr_size(
          * they get written to.
          */
         ip->i_d.di_size = newsize;
-        ip->i_size = newsize;
         xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
 
         if (newsize <= oldsize) {
diff --git a/fs/xfs/xfs_qm_syscalls.c b/fs/xfs/xfs_qm_syscalls.c
index 27378650b5c..eafbcff81f3 100644
--- a/fs/xfs/xfs_qm_syscalls.c
+++ b/fs/xfs/xfs_qm_syscalls.c
@@ -265,7 +265,6 @@ xfs_qm_scall_trunc_qfile(
         xfs_trans_ijoin(tp, ip, 0);
 
         ip->i_d.di_size = 0;
-        ip->i_size = 0;
         xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
 
         error = xfs_itruncate_extents(&tp, ip, XFS_DATA_FORK, 0);
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index 81efa041617..2aabcc9c507 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -1038,7 +1038,7 @@ DECLARE_EVENT_CLASS(xfs_simple_io_class,
         TP_fast_assign(
                 __entry->dev = VFS_I(ip)->i_sb->s_dev;
                 __entry->ino = ip->i_ino;
-                __entry->isize = ip->i_size;
+                __entry->isize = VFS_I(ip)->i_size;
                 __entry->disize = ip->i_d.di_size;
                 __entry->new_size = ip->i_new_size;
                 __entry->offset = offset;
diff --git a/fs/xfs/xfs_vnodeops.c b/fs/xfs/xfs_vnodeops.c
index 96ff0342175..0cf52da9d24 100644
--- a/fs/xfs/xfs_vnodeops.c
+++ b/fs/xfs/xfs_vnodeops.c
@@ -175,7 +175,7 @@ xfs_free_eofblocks(
          * Figure out if there are any blocks beyond the end
          * of the file.  If not, then there is nothing to do.
          */
-        end_fsb = XFS_B_TO_FSB(mp, ((xfs_ufsize_t)ip->i_size));
+        end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)XFS_ISIZE(ip));
         last_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)XFS_MAXIOFFSET(mp));
         if (last_fsb <= end_fsb)
                 return 0;
@@ -233,7 +233,7 @@ xfs_free_eofblocks(
                  * may be full of holes (ie NULL files bug).
                  */
                 error = xfs_itruncate_extents(&tp, ip, XFS_DATA_FORK,
-                                              ip->i_size);
+                                              XFS_ISIZE(ip));
                 if (error) {
                         /*
                          * If we get an error at this point we simply don't
@@ -547,8 +547,8 @@ xfs_release(
                 return 0;
 
         if ((S_ISREG(ip->i_d.di_mode) &&
-             ((ip->i_size > 0) || (VN_CACHED(VFS_I(ip)) > 0 ||
-               ip->i_delayed_blks > 0)) &&
+             (VFS_I(ip)->i_size > 0 ||
+              (VN_CACHED(VFS_I(ip)) > 0 || ip->i_delayed_blks > 0)) &&
              (ip->i_df.if_flags & XFS_IFEXTENTS))  &&
             (!(ip->i_d.di_flags & (XFS_DIFLAG_PREALLOC | XFS_DIFLAG_APPEND)))) {
 
@@ -625,7 +625,7 @@ xfs_inactive(
          * only one with a reference to the inode.
          */
         truncate = ((ip->i_d.di_nlink == 0) &&
-            ((ip->i_d.di_size != 0) || (ip->i_size != 0) ||
+            ((ip->i_d.di_size != 0) || XFS_ISIZE(ip) != 0 ||
              (ip->i_d.di_nextents > 0) || (ip->i_delayed_blks > 0)) &&
             S_ISREG(ip->i_d.di_mode));
 
@@ -639,12 +639,12 @@ xfs_inactive(
 
         if (ip->i_d.di_nlink != 0) {
                 if ((S_ISREG(ip->i_d.di_mode) &&
-                     ((ip->i_size > 0) || (VN_CACHED(VFS_I(ip)) > 0 ||
-                       ip->i_delayed_blks > 0)) &&
-                      (ip->i_df.if_flags & XFS_IFEXTENTS) &&
-                     (!(ip->i_d.di_flags &
+                    (VFS_I(ip)->i_size > 0 ||
+                     (VN_CACHED(VFS_I(ip)) > 0 || ip->i_delayed_blks > 0)) &&
+                    (ip->i_df.if_flags & XFS_IFEXTENTS) &&
+                    (!(ip->i_d.di_flags &
                                 (XFS_DIFLAG_PREALLOC | XFS_DIFLAG_APPEND)) ||
-                      (ip->i_delayed_blks != 0)))) {
+                     ip->i_delayed_blks != 0))) {
                         error = xfs_free_eofblocks(mp, ip, 0);
                         if (error)
                                 return VN_INACTIVE_CACHE;
@@ -678,7 +678,6 @@ xfs_inactive(
                 xfs_trans_ijoin(tp, ip, 0);
 
                 ip->i_d.di_size = 0;
-                ip->i_size = 0;
                 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
 
                 error = xfs_itruncate_extents(&tp, ip, XFS_DATA_FORK, 0);
@@ -1974,11 +1973,11 @@ xfs_zero_remaining_bytes(
          * since nothing can read beyond eof.  The space will
          * be zeroed when the file is extended anyway.
          */
-        if (startoff >= ip->i_size)
+        if (startoff >= XFS_ISIZE(ip))
                 return 0;
 
-        if (endoff > ip->i_size)
-                endoff = ip->i_size;
+        if (endoff > XFS_ISIZE(ip))
+                endoff = XFS_ISIZE(ip);
 
         bp = xfs_buf_get_uncached(XFS_IS_REALTIME_INODE(ip) ?
                                         mp->m_rtdev_targp : mp->m_ddev_targp,
@@ -2273,7 +2272,7 @@ xfs_change_file_space(
                 bf->l_start += offset;
                 break;
         case 2: /*SEEK_END*/
-                bf->l_start += ip->i_size;
+                bf->l_start += XFS_ISIZE(ip);
                 break;
         default:
                 return XFS_ERROR(EINVAL);
@@ -2290,7 +2289,7 @@ xfs_change_file_space(
         bf->l_whence = 0;
 
         startoffset = bf->l_start;
-        fsize = ip->i_size;
+        fsize = XFS_ISIZE(ip);
 
         /*
          * XFS_IOC_RESVSP and XFS_IOC_UNRESVSP will reserve or unreserve