From 2d3fda8c82c24b01537ed10fe614ce5eea130754 Mon Sep 17 00:00:00 2001
From: Derrick Brashear <shadow@dementia.org>
Date: Mon, 10 Nov 2003 01:36:09 +0000
Subject: [PATCH] linux-sysname-list-sys-links-resolve-dentry-20031109

without this, if you're in a directory that the second or later entry in a
sysname list resolved to, pwd returns ESTALE. force the true path to have its
dentry cached.
---
 src/afs/LINUX/osi_vnodeops.c | 85 +++++++++++++++++++-----------------
 1 file changed, 46 insertions(+), 39 deletions(-)

diff --git a/src/afs/LINUX/osi_vnodeops.c b/src/afs/LINUX/osi_vnodeops.c
index 0e0ec36b18..413a893ca7 100644
--- a/src/afs/LINUX/osi_vnodeops.c
+++ b/src/afs/LINUX/osi_vnodeops.c
@@ -957,43 +957,6 @@ afs_linux_dentry_revalidate(struct dentry *dp)
     return !bad_dentry;
 }
 
-#ifdef notdef
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,2,10)
-static int
-afs_linux_dentry_revalidate(struct dentry *dp, int flags)
-#else
-static int
-afs_linux_dentry_revalidate(struct dentry *dp)
-#endif
-{
-    int code;
-    cred_t *credp;
-    struct vrequest treq;
-    struct inode *ip = AFSTOI(dp->d_inode);
-
-    unsigned long timeout = 3 * HZ;	/* 3 seconds */
-
-    if (!ip)
-	printk("negative dentry: %s\n", dp->d_name.name);
-
-    if (!(flags & LOOKUP_CONTINUE)) {
-	long diff = CURRENT_TIME - dp->d_parent->d_inode->i_mtime;
-
-	if (diff < 15 * 60)
-	    timeout = 0;
-    }
-
-    if (time_after(jiffies, dp->d_time + timeout))
-	goto out_bad;
-
-  out_valid:
-    return 1;
-
-  out_bad:
-    return 0;
-}
-#endif
-
 /* afs_dentry_iput */
 static void
 afs_dentry_iput(struct dentry *dp, struct inode *ip)
@@ -1109,6 +1072,8 @@ afs_linux_create(struct inode *dip, struct dentry *dp, int mode)
     return -code;
 }
 
+#define AFS_EQ_ATSYS(name) (((name)[0]=='@')&&((name)[1]=='s')&&((name)[2]=='y')&&((name)[3]=='s')&&(!(name)[4]))
+
 /* afs_linux_lookup */
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,2,10)
 struct dentry *
@@ -1122,9 +1087,30 @@ afs_linux_lookup(struct inode *dip, struct dentry *dp)
     cred_t *credp = crref();
     struct vcache *vcp = NULL;
     const char *comp = dp->d_name.name;
-    AFS_GLOCK();
-    code = afs_lookup(ITOAFS(dip), comp, &vcp, credp);
+    char *name = NULL;
+    struct sysname_info sysState;
+    struct qstr qstr;
+    struct vrequest treq;
 
+    sysState.allocked = 0;
+
+    AFS_GLOCK();
+
+    /* In order that we not get ESTALE on @sys links that resolve
+       into the 2nd or later item in an @sys list, resolve it ourselves
+       and force a lookup of the actual match here. The real directory
+       thus gets the dentry. */
+    if (AFS_EQ_ATSYS(comp) && !afs_InitReq(&treq, credp)) {
+	Check_AtSys(ITOAFS(dip), comp, &sysState, &treq);
+	name = sysState.name;
+
+	code = afs_lookup(ITOAFS(dip), name, &vcp, credp);
+	while (code == ENOENT && Next_AtSys(ITOAFS(dip), &treq, &sysState)) {
+	    code = afs_lookup(ITOAFS(dip), name, &vcp, credp);
+	}
+    } else
+	code = afs_lookup(ITOAFS(dip), comp, &vcp, credp);
+    
     if (vcp) {
 	struct inode *ip = AFSTOI(vcp);
 	/* Reset ops if symlink or directory. */
@@ -1155,6 +1141,27 @@ afs_linux_lookup(struct inode *dip, struct dentry *dp)
     dp->d_op = afs_dops;
     d_add(dp, AFSTOI(vcp));
 
+#if 0
+    /* Set up a dentry alias. Should we be doing this for @sys?
+       You only get one for a directory, which would be fine,
+       @sys would only map to one at a time, but it's unclear
+       that this is consistent behavior. */
+    if (AFS_EQ_ATSYS(comp) && sysState.allocked) {
+	int result;
+	struct dentry *dentry;
+
+	qstr.name = name;
+	qstr.len  = strlen(name);
+	qstr.hash = full_name_hash(name, qstr.len);
+	result = d_lookup(dp->d_parent, &qstr);
+	if (!result) {
+	    dentry = d_alloc(dp->d_parent, &qstr);
+	    if (dentry)
+		d_instantiate(dentry, AFSTOI(vcp));
+	}
+    }
+#endif
+
     AFS_GUNLOCK();
     crfree(credp);