untangling do_lookup() - get rid of need_reval in !dentry case (08b0ab7c) · Commits · 戴 / test

Everything arriving into if (!dentry) will have need_reval = 1. Indeed, the only way to get there with need_reval reset to 0 would be via if (unlikely(d_need_lookup(dentry))) goto unlazy; if (unlikely(dentry->d_flags & DCACHE_OP_REVALIDATE)) { status = d_revalidate(dentry, nd); if (unlikely(status <= 0)) { if (status != -ECHILD) need_reval = 0; goto unlazy; ... unlazy: /* no assignments to dentry */ if (dentry && unlikely(d_need_lookup(dentry))) { dput(dentry); dentry = NULL; } and if d_need_lookup() had already been false the first time around, it will remain false on the second call as well. Signed-off-by:

Al Viro <viro@zeniv.linux.org.uk>

fs/namei.c

+1 −6

Original line number	Diff line number	Diff line
		@@ -1181,7 +1181,6 @@ retry:
		return PTR_ERR(dentry);
		}
		/* known good */
		need_reval = 0;
		status = 1;
		} else if (unlikely(d_need_lookup(dentry))) {
		dentry = d_inode_lookup(parent, dentry, nd);
		@@ -1190,10 +1189,8 @@ retry:
		return PTR_ERR(dentry);
		}
		/* known good */
		need_reval = 0;
		status = 1;
		}
		if (unlikely(dentry->d_flags & DCACHE_OP_REVALIDATE) && need_reval)
		} else if (unlikely(dentry->d_flags & DCACHE_OP_REVALIDATE))
		status = d_revalidate(dentry, nd);
		if (unlikely(status <= 0)) {
		if (status < 0) {
		@@ -1209,7 +1206,6 @@ retry:
		return PTR_ERR(dentry);
		}
		/* known good */
		need_reval = 0;
		status = 1;
		}
		}
		@@ -1226,7 +1222,6 @@ retry:
		if (!d_invalidate(dentry)) {
		dput(dentry);
		dentry = NULL;
		need_reval = 1;
		goto retry;
		}
		}

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