xfs: separate primary inode selection criteria in xfs_iget_cache_hit

During review of the v6 deferred inode inactivation patchset[1], Dave
commented that _cache_hit should have a clear separation between inode
selection criteria and actions performed on a selected inode.  Move a
hunk to make this true, and compact the shrink cases in the function.

[1] https://lore.kernel.org/linux-xfs/162310469340.3465262.504398465311182657.stgit@locust/T/#mca6d958521cb88bbc1bfe1a30767203328d410b5
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Brian Foster <bfoster@redhat.com>

diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
index 3722951..6b44fc7 100644 (file)
--- a/fs/xfs/xfs_icache.c
+++ b/fs/xfs/xfs_icache.c
@@ -507,13 +507,8 @@ xfs_iget_cache_hit(
         * will not match, so check for that, too.
         */
        spin_lock(&ip->i_flags_lock);
-       if (ip->i_ino != ino) {
-               trace_xfs_iget_skip(ip);
-               XFS_STATS_INC(mp, xs_ig_frecycle);
-               error = -EAGAIN;
-               goto out_error;
-       }
-
+       if (ip->i_ino != ino)
+               goto out_skip;
 
        /*
         * If we are racing with another cache hit that is currently
@@ -525,12 +520,8 @@ xfs_iget_cache_hit(
         *           wait_on_inode to wait for these flags to be cleared
         *           instead of polling for it.
         */
-       if (ip->i_flags & (XFS_INEW|XFS_IRECLAIM)) {
-               trace_xfs_iget_skip(ip);
-               XFS_STATS_INC(mp, xs_ig_frecycle);
-               error = -EAGAIN;
-               goto out_error;
-       }
+       if (ip->i_flags & (XFS_INEW | XFS_IRECLAIM))
+               goto out_skip;
 
        /*
         * Check the inode free state is valid. This also detects lookup
@@ -540,23 +531,21 @@ xfs_iget_cache_hit(
        if (error)
                goto out_error;
 
-       if (ip->i_flags & XFS_IRECLAIMABLE) {
-               if (flags & XFS_IGET_INCORE) {
-                       error = -EAGAIN;
-                       goto out_error;
-               }
+       /* Skip inodes that have no vfs state. */
+       if ((flags & XFS_IGET_INCORE) &&
+           (ip->i_flags & XFS_IRECLAIMABLE))
+               goto out_skip;
 
+       /* The inode fits the selection criteria; process it. */
+       if (ip->i_flags & XFS_IRECLAIMABLE) {
                /* Drops i_flags_lock and RCU read lock. */
                error = xfs_iget_recycle(pag, ip);
                if (error)
                        return error;
        } else {
                /* If the VFS inode is being torn down, pause and try again. */
-               if (!igrab(inode)) {
-                       trace_xfs_iget_skip(ip);
-                       error = -EAGAIN;
-                       goto out_error;
-               }
+               if (!igrab(inode))
+                       goto out_skip;
 
                /* We've got a live one. */
                spin_unlock(&ip->i_flags_lock);
@@ -573,6 +562,10 @@ xfs_iget_cache_hit(
 
        return 0;
 
+out_skip:
+       trace_xfs_iget_skip(ip);
+       XFS_STATS_INC(mp, xs_ig_frecycle);
+       error = -EAGAIN;
 out_error:
        spin_unlock(&ip->i_flags_lock);
        rcu_read_unlock();