xfs: remove xfs_iread

There is not much point in the xfs_iread function, as it has a single
caller and not a whole lot of code.  Move it into the only caller,
and trim down the overdocumentation to just documenting the important
"why" instead of a lot of redundant "what".

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

fs/xfs/libxfs/xfs_inode_buf.c

@@ -614,79 +614,6 @@ xfs_dinode_calc_crc(
 	dip->di_crc = xfs_end_cksum(crc);
 }
 
-/*
- * Read the disk inode attributes into the in-core inode structure.
- *
- * For version 5 superblocks, if we are initialising a new inode and we are not
- * utilising the XFS_MOUNT_IKEEP inode cluster mode, we can simple build the new
- * inode core with a random generation number. If we are keeping inodes around,
- * we need to read the inode cluster to get the existing generation number off
- * disk. Further, if we are using version 4 superblocks (i.e. v1/v2 inode
- * format) then log recovery is dependent on the di_flushiter field being
- * initialised from the current on-disk value and hence we must also read the
- * inode off disk.
- */
-int
-xfs_iread(
-	xfs_mount_t	*mp,
-	xfs_trans_t	*tp,
-	xfs_inode_t	*ip,
-	uint		iget_flags)
-{
-	xfs_buf_t	*bp;
-	xfs_dinode_t	*dip;
-	int		error;
-
-	/*
-	 * Fill in the location information in the in-core inode.
-	 */
-	error = xfs_imap(mp, tp, ip->i_ino, &ip->i_imap, iget_flags);
-	if (error)
-		return error;
-
-	/* shortcut IO on inode allocation if possible */
-	if ((iget_flags & XFS_IGET_CREATE) &&
-	    xfs_sb_version_has_v3inode(&mp->m_sb) &&
-	    !(mp->m_flags & XFS_MOUNT_IKEEP)) {
-		VFS_I(ip)->i_generation = prandom_u32();
-		return 0;
-	}
-
-	/*
-	 * Get pointers to the on-disk inode and the buffer containing it.
-	 */
-	error = xfs_imap_to_bp(mp, tp, &ip->i_imap, &dip, &bp, 0);
-	if (error)
-		return error;
-
-	error = xfs_inode_from_disk(ip, dip);
-	if (error)
-		goto out_brelse;
-
-	/*
-	 * Mark the buffer containing the inode as something to keep
-	 * around for a while.  This helps to keep recently accessed
-	 * meta-data in-core longer.
-	 */
-	xfs_buf_set_ref(bp, XFS_INO_REF);
-
-	/*
-	 * Use xfs_trans_brelse() to release the buffer containing the on-disk
-	 * inode, because it was acquired with xfs_trans_read_buf() in
-	 * xfs_imap_to_bp() above.  If tp is NULL, this is just a normal
-	 * brelse().  If we're within a transaction, then xfs_trans_brelse()
-	 * will only release the buffer if it is not dirty within the
-	 * transaction.  It will be OK to release the buffer in this case,
-	 * because inodes on disk are never destroyed and we will be locking the
-	 * new in-core inode before putting it in the cache where other
-	 * processes can find it.  Thus we don't have to worry about the inode
-	 * being changed just because we released the buffer.
-	 */
- out_brelse:
-	xfs_trans_brelse(tp, bp);
-	return error;
-}
-
 /*
  * Validate di_extsize hint.
  *

fs/xfs/libxfs/xfs_inode_buf.h

@@ -49,8 +49,6 @@ struct xfs_imap {
 int	xfs_imap_to_bp(struct xfs_mount *, struct xfs_trans *,
 		       struct xfs_imap *, struct xfs_dinode **,
 		       struct xfs_buf **, uint);
-int	xfs_iread(struct xfs_mount *, struct xfs_trans *,
-		  struct xfs_inode *, uint);
 void	xfs_dinode_calc_crc(struct xfs_mount *, struct xfs_dinode *);
 void	xfs_inode_to_disk(struct xfs_inode *ip, struct xfs_dinode *to,
 			  xfs_lsn_t lsn);

fs/xfs/xfs_icache.c

@@ -22,6 +22,7 @@
 #include "xfs_dquot_item.h"
 #include "xfs_dquot.h"
 #include "xfs_reflink.h"
+#include "xfs_ialloc.h"
 
 #include <linux/iversion.h>
 
@@ -508,10 +509,40 @@ xfs_iget_cache_miss(
 	if (!ip)
 		return -ENOMEM;
 
-	error = xfs_iread(mp, tp, ip, flags);
+	error = xfs_imap(mp, tp, ip->i_ino, &ip->i_imap, flags);
 	if (error)
 		goto out_destroy;
 
+	/*
+	 * For version 5 superblocks, if we are initialising a new inode and we
+	 * are not utilising the XFS_MOUNT_IKEEP inode cluster mode, we can
+	 * simply build the new inode core with a random generation number.
+	 *
+	 * For version 4 (and older) superblocks, log recovery is dependent on
+	 * the di_flushiter field being initialised from the current on-disk
+	 * value and hence we must also read the inode off disk even when
+	 * initializing new inodes.
+	 */
+	if (xfs_sb_version_has_v3inode(&mp->m_sb) &&
+	    (flags & XFS_IGET_CREATE) && !(mp->m_flags & XFS_MOUNT_IKEEP)) {
+		VFS_I(ip)->i_generation = prandom_u32();
+	} else {
+		struct xfs_dinode	*dip;
+		struct xfs_buf		*bp;
+
+		error = xfs_imap_to_bp(mp, tp, &ip->i_imap, &dip, &bp, 0);
+		if (error)
+			goto out_destroy;
+
+		error = xfs_inode_from_disk(ip, dip);
+		if (!error)
+			xfs_buf_set_ref(bp, XFS_INO_REF);
+		xfs_trans_brelse(tp, bp);
+
+		if (error)
+			goto out_destroy;
+	}
+
 	if (!xfs_inode_verify_forks(ip)) {
 		error = -EFSCORRUPTED;
 		goto out_destroy;