xfs: use vfs inode nlink field everywhere

The VFS tracks the inode nlink just like the xfs_icdinode. We can
remove the variable from the icdinode and use the VFS inode variable
everywhere, reducing the size of the xfs_icdinode by a further 4
bytes.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>

9 files changed, 43 insertions, 54 deletions

diff --git a/fs/xfs/libxfs/xfs_inode_buf.c b/fs/xfs/libxfs/xfs_inode_buf.c
index fe8f4f349b37..cc509c1af75e 100644
--- a/fs/xfs/libxfs/xfs_inode_buf.c
+++ b/fs/xfs/libxfs/xfs_inode_buf.c
@@ -210,12 +210,12 @@ xfs_inode_from_disk(
          * minimum inode version format we support in the rest of the code.
          */
         if (to->di_version == 1) {
-                to->di_nlink = be16_to_cpu(from->di_onlink);
+                set_nlink(inode, be16_to_cpu(from->di_onlink));
                 to->di_projid_lo = 0;
                 to->di_projid_hi = 0;
                 to->di_version = 2;
         } else {
-                to->di_nlink = be32_to_cpu(from->di_nlink);
+                set_nlink(inode, be32_to_cpu(from->di_nlink));
                 to->di_projid_lo = be16_to_cpu(from->di_projid_lo);
                 to->di_projid_hi = be16_to_cpu(from->di_projid_hi);
         }
@@ -275,7 +275,6 @@ xfs_inode_to_disk(
         to->di_format = from->di_format;
         to->di_uid = cpu_to_be32(from->di_uid);
         to->di_gid = cpu_to_be32(from->di_gid);
-        to->di_nlink = cpu_to_be32(from->di_nlink);
         to->di_projid_lo = cpu_to_be16(from->di_projid_lo);
         to->di_projid_hi = cpu_to_be16(from->di_projid_hi);
 
@@ -286,6 +285,7 @@ xfs_inode_to_disk(
         to->di_mtime.t_nsec = cpu_to_be32(inode->i_mtime.tv_nsec);
         to->di_ctime.t_sec = cpu_to_be32(inode->i_ctime.tv_sec);
         to->di_ctime.t_nsec = cpu_to_be32(inode->i_ctime.tv_nsec);
+        to->di_nlink = cpu_to_be32(inode->i_nlink);
 
         to->di_size = cpu_to_be64(from->di_size);
         to->di_nblocks = cpu_to_be64(from->di_nblocks);
diff --git a/fs/xfs/libxfs/xfs_inode_buf.h b/fs/xfs/libxfs/xfs_inode_buf.h
index 73ba1d8ffac2..320b72344270 100644
--- a/fs/xfs/libxfs/xfs_inode_buf.h
+++ b/fs/xfs/libxfs/xfs_inode_buf.h
@@ -34,7 +34,6 @@ struct xfs_icdinode {
         __uint16_t      di_flushiter;   /* incremented on flush */
         __uint32_t      di_uid;         /* owner's user id */
         __uint32_t      di_gid;         /* owner's group id */
-        __uint32_t      di_nlink;       /* number of links to file */
         __uint16_t      di_projid_lo;   /* lower part of owner's project id */
         __uint16_t      di_projid_hi;   /* higher part of owner's project id */
         xfs_fsize_t     di_size;        /* number of bytes in file */
diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
index 9ca2865575ab..4c184f70d43c 100644
--- a/fs/xfs/xfs_icache.c
+++ b/fs/xfs/xfs_icache.c
@@ -148,9 +148,11 @@ xfs_reinit_inode(
         struct inode            *inode)
 {
         int             error;
+        uint32_t        nlink = inode->i_nlink;
 
         error = inode_init_always(mp->m_super, inode);
 
+        set_nlink(inode, nlink);
         return error;
 }
 
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 7d9c514fd231..18b3bc0c211a 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -57,9 +57,9 @@ kmem_zone_t *xfs_inode_zone;
  */
 #define XFS_ITRUNC_MAX_EXTENTS  2
 
-STATIC int xfs_iflush_int(xfs_inode_t *, xfs_buf_t *);
-
-STATIC int xfs_iunlink_remove(xfs_trans_t *, xfs_inode_t *);
+STATIC int xfs_iflush_int(struct xfs_inode *, struct xfs_buf *);
+STATIC int xfs_iunlink(struct xfs_trans *, struct xfs_inode *);
+STATIC int xfs_iunlink_remove(struct xfs_trans *, struct xfs_inode *);
 
 /*
  * helper function to extract extent size hint from inode
@@ -803,7 +803,7 @@ xfs_ialloc(
                 ip->i_d.di_version = 2;
 
         ip->i_d.di_mode = mode;
-        ip->i_d.di_nlink = nlink;
+        set_nlink(inode, nlink);
         ip->i_d.di_uid = xfs_kuid_to_uid(current_fsuid());
         ip->i_d.di_gid = xfs_kgid_to_gid(current_fsgid());
         xfs_set_projid(ip, prid);
@@ -1086,35 +1086,24 @@ xfs_dir_ialloc(
 }
 
 /*
- * Decrement the link count on an inode & log the change.
- * If this causes the link count to go to zero, initiate the
- * logging activity required to truncate a file.
+ * Decrement the link count on an inode & log the change.  If this causes the
+ * link count to go to zero, move the inode to AGI unlinked list so that it can
+ * be freed when the last active reference goes away via xfs_inactive().
  */
 int                             /* error */
 xfs_droplink(
         xfs_trans_t *tp,
         xfs_inode_t *ip)
 {
-        int     error;
-
         xfs_trans_ichgtime(tp, ip, XFS_ICHGTIME_CHG);
 
-        ASSERT (ip->i_d.di_nlink > 0);
-        ip->i_d.di_nlink--;
         drop_nlink(VFS_I(ip));
         xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
 
-        error = 0;
-        if (ip->i_d.di_nlink == 0) {
-                /*
-                 * We're dropping the last link to this file.
-                 * Move the on-disk inode to the AGI unlinked list.
-                 * From xfs_inactive() we will pull the inode from
-                 * the list and free it.
-                 */
-                error = xfs_iunlink(tp, ip);
-        }
-        return error;
+        if (VFS_I(ip)->i_nlink)
+                return 0;
+
+        return xfs_iunlink(tp, ip);
 }
 
 /*
@@ -1128,8 +1117,6 @@ xfs_bumplink(
         xfs_trans_ichgtime(tp, ip, XFS_ICHGTIME_CHG);
 
         ASSERT(ip->i_d.di_version > 1);
-        ASSERT(ip->i_d.di_nlink > 0 || (VFS_I(ip)->i_state & I_LINKABLE));
-        ip->i_d.di_nlink++;
         inc_nlink(VFS_I(ip));
         xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
         return 0;
@@ -1387,7 +1374,6 @@ xfs_create_tmpfile(
          */
         xfs_qm_vop_create_dqattach(tp, ip, udqp, gdqp, pdqp);
 
-        ip->i_d.di_nlink--;
         error = xfs_iunlink(tp, ip);
         if (error)
                 goto out_trans_cancel;
@@ -1486,7 +1472,10 @@ xfs_link(
 
         xfs_bmap_init(&free_list, &first_block);
 
-        if (sip->i_d.di_nlink == 0) {
+        /*
+         * Handle initial link state of O_TMPFILE inode
+         */
+        if (VFS_I(sip)->i_nlink == 0) {
                 error = xfs_iunlink_remove(tp, sip);
                 if (error)
                         goto error_return;
@@ -1673,7 +1662,7 @@ xfs_release(
                 }
         }
 
-        if (ip->i_d.di_nlink == 0)
+        if (VFS_I(ip)->i_nlink == 0)
                 return 0;
 
         if (xfs_can_free_eofblocks(ip, false)) {
@@ -1889,7 +1878,7 @@ xfs_inactive(
         if (mp->m_flags & XFS_MOUNT_RDONLY)
                 return;
 
-        if (ip->i_d.di_nlink != 0) {
+        if (VFS_I(ip)->i_nlink != 0) {
                 /*
                  * force is true because we are evicting an inode from the
                  * cache. Post-eof blocks must be freed, lest we end up with
@@ -1946,16 +1935,21 @@ xfs_inactive(
 }
 
 /*
- * This is called when the inode's link count goes to 0.
- * We place the on-disk inode on a list in the AGI.  It
- * will be pulled from this list when the inode is freed.
+ * This is called when the inode's link count goes to 0 or we are creating a
+ * tmpfile via O_TMPFILE. In the case of a tmpfile, @ignore_linkcount will be
+ * set to true as the link count is dropped to zero by the VFS after we've
+ * created the file successfully, so we have to add it to the unlinked list
+ * while the link count is non-zero.
+ *
+ * We place the on-disk inode on a list in the AGI.  It will be pulled from this
+ * list when the inode is freed.
  */
-int
+STATIC int
 xfs_iunlink(
-        xfs_trans_t     *tp,
-        xfs_inode_t     *ip)
+        struct xfs_trans *tp,
+        struct xfs_inode *ip)
 {
-        xfs_mount_t     *mp;
+        xfs_mount_t     *mp = tp->t_mountp;
         xfs_agi_t       *agi;
         xfs_dinode_t    *dip;
         xfs_buf_t       *agibp;
@@ -1965,11 +1959,8 @@ xfs_iunlink(
         int             offset;
         int             error;
 
-        ASSERT(ip->i_d.di_nlink == 0);
         ASSERT(ip->i_d.di_mode != 0);
 
-        mp = tp->t_mountp;
-
         /*
          * Get the agi buffer first.  It ensures lock ordering
          * on the list.
@@ -2406,7 +2397,7 @@ xfs_ifree(
         struct xfs_icluster     xic = { 0 };
 
         ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
-        ASSERT(ip->i_d.di_nlink == 0);
+        ASSERT(VFS_I(ip)->i_nlink == 0);
         ASSERT(ip->i_d.di_nextents == 0);
         ASSERT(ip->i_d.di_anextents == 0);
         ASSERT(ip->i_d.di_size == 0 || !S_ISREG(ip->i_d.di_mode));
@@ -2574,8 +2565,8 @@ xfs_remove(
          * If we're removing a directory perform some additional validation.
          */
         if (is_dir) {
-                ASSERT(ip->i_d.di_nlink >= 2);
-                if (ip->i_d.di_nlink != 2) {
+                ASSERT(VFS_I(ip)->i_nlink >= 2);
+                if (VFS_I(ip)->i_nlink != 2) {
                         error = -ENOTEMPTY;
                         goto out_trans_cancel;
                 }
@@ -3031,7 +3022,7 @@ xfs_rename(
                          * Make sure target dir is empty.
                          */
                         if (!(xfs_dir_isempty(target_ip)) ||
-                            (target_ip->i_d.di_nlink > 2)) {
+                            (VFS_I(target_ip)->i_nlink > 2)) {
                                 error = -EEXIST;
                                 goto out_trans_cancel;
                         }
@@ -3138,7 +3129,7 @@ xfs_rename(
          * intermediate state on disk.
          */
         if (wip) {
-                ASSERT(VFS_I(wip)->i_nlink == 0 && wip->i_d.di_nlink == 0);
+                ASSERT(VFS_I(wip)->i_nlink == 0);
                 error = xfs_bumplink(tp, wip);
                 if (error)
                         goto out_bmap_cancel;
diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index aef5452b1a90..e74d13d3076b 100644
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h
@@ -405,8 +405,6 @@ int		xfs_ifree(struct xfs_trans *, xfs_inode_t *,
                            struct xfs_bmap_free *);
 int             xfs_itruncate_extents(struct xfs_trans **, struct xfs_inode *,
                                       int, xfs_fsize_t);
-int             xfs_iunlink(struct xfs_trans *, xfs_inode_t *);
-
 void            xfs_iext_realloc(xfs_inode_t *, int, int);
 
 void            xfs_iunpin_wait(xfs_inode_t *);
diff --git a/fs/xfs/xfs_inode_item.c b/fs/xfs/xfs_inode_item.c
index 1e5ecbc45459..193e0bdec340 100644
--- a/fs/xfs/xfs_inode_item.c
+++ b/fs/xfs/xfs_inode_item.c
@@ -338,7 +338,6 @@ xfs_inode_to_log_dinode(
         to->di_format = from->di_format;
         to->di_uid = from->di_uid;
         to->di_gid = from->di_gid;
-        to->di_nlink = from->di_nlink;
         to->di_projid_lo = from->di_projid_lo;
         to->di_projid_hi = from->di_projid_hi;
 
@@ -350,6 +349,7 @@ xfs_inode_to_log_dinode(
         to->di_mtime.t_nsec = inode->i_mtime.tv_nsec;
         to->di_ctime.t_sec = inode->i_ctime.tv_sec;
         to->di_ctime.t_nsec = inode->i_ctime.tv_nsec;
+        to->di_nlink = inode->i_nlink;
 
         to->di_size = from->di_size;
         to->di_nblocks = from->di_nblocks;
diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index cd27c6d56dfc..8982e56e07c4 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -460,7 +460,7 @@ xfs_vn_getattr(
         stat->size = XFS_ISIZE(ip);
         stat->dev = inode->i_sb->s_dev;
         stat->mode = ip->i_d.di_mode;
-        stat->nlink = ip->i_d.di_nlink;
+        stat->nlink = inode->i_nlink;
         stat->uid = inode->i_uid;
         stat->gid = inode->i_gid;
         stat->ino = ip->i_ino;
@@ -1216,7 +1216,6 @@ xfs_setup_inode(
         hlist_add_fake(&inode->i_hash);
 
         inode->i_mode   = ip->i_d.di_mode;
-        set_nlink(inode, ip->i_d.di_nlink);
         inode->i_uid    = xfs_uid_to_kuid(ip->i_d.di_uid);
         inode->i_gid    = xfs_gid_to_kgid(ip->i_d.di_gid);
 
diff --git a/fs/xfs/xfs_itable.c b/fs/xfs/xfs_itable.c
index 2acda42319f5..cfb65273d361 100644
--- a/fs/xfs/xfs_itable.c
+++ b/fs/xfs/xfs_itable.c
@@ -85,7 +85,6 @@ xfs_bulkstat_one_int(
         /* xfs_iget returns the following without needing
          * further change.
          */
-        buf->bs_nlink = dic->di_nlink;
         buf->bs_projid_lo = dic->di_projid_lo;
         buf->bs_projid_hi = dic->di_projid_hi;
         buf->bs_ino = ino;
@@ -94,6 +93,7 @@ xfs_bulkstat_one_int(
         buf->bs_gid = dic->di_gid;
         buf->bs_size = dic->di_size;
 
+        buf->bs_nlink = inode->i_nlink;
         buf->bs_atime.tv_sec = inode->i_atime.tv_sec;
         buf->bs_atime.tv_nsec = inode->i_atime.tv_nsec;
         buf->bs_mtime.tv_sec = inode->i_mtime.tv_sec;
diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
index 4b79cf006589..611c25cdb15c 100644
--- a/fs/xfs/xfs_log_recover.c
+++ b/fs/xfs/xfs_log_recover.c
@@ -4337,7 +4337,7 @@ xlog_recover_process_one_iunlink(
         if (error)
                 goto fail_iput;
 
-        ASSERT(ip->i_d.di_nlink == 0);
+        ASSERT(VFS_I(ip)->i_nlink == 0);
         ASSERT(ip->i_d.di_mode != 0);
 
         /* setup for the next pass */