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From 3506b7d9cb6b7f869c2f12796388ba3966b6ad42 Mon Sep 17 00:00:00 2001
From: Cheyenne Wills <cwills@sinenomine.net>
Date: Fri, 14 Feb 2025 15:18:52 -0700
Subject: [PATCH 1/2] LINUX: Refactor afs_linux_dentry_revalidate()
The signature for Linux's dentry_operations.d_revalidate method has
undergone several changes, leading to increased use of #if directives in
afs_linux_dentry_revalidate().
To make the code more maintainable for future changes involving the
parent inode and the dentry's name, split out most of our logic in
afs_linux_dentry_revalidate() into a new function,
dentry_revalidate_common(). Keep the logic for getting the parent and
checking for LOOKUP_RCU in the caller, afs_linux_dentry_revalidate().
Written in collaboration with adeason@sinenomine.net.
Reviewed-on: https://gerrit.openafs.org/16258
Reviewed-by: Michael Meffie <mmeffie@sinenomine.net>
Reviewed-by: Mark Vitale <mvitale@sinenomine.net>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Cheyenne Wills <cwills@sinenomine.net>
Tested-by: Cheyenne Wills <cwills@sinenomine.net>
Reviewed-by: Andrew Deason <adeason@sinenomine.net>
(cherry picked from commit 4702930f8dd87a6cad1d59ef8c127003fded1f31)
Change-Id: Iae781913ec933e79ca47cdf043e729e50c1b2a6d
---
src/afs/LINUX/osi_vnodeops.c | 92 ++++++++++++++++++------------------
1 file changed, 47 insertions(+), 45 deletions(-)
diff --git a/src/afs/LINUX/osi_vnodeops.c b/src/afs/LINUX/osi_vnodeops.c
index 519c5da15..e9d948989 100644
--- a/src/afs/LINUX/osi_vnodeops.c
+++ b/src/afs/LINUX/osi_vnodeops.c
@@ -1382,43 +1382,24 @@ check_dentry_race(struct dentry *dp)
}
#endif /* D_SPLICE_ALIAS_RACE */
-/* Validate a dentry. Return 1 if unchanged, 0 if VFS layer should re-evaluate.
- * In kernels 2.2.10 and above, we are passed an additional flags var which
- * may have either the LOOKUP_FOLLOW OR LOOKUP_DIRECTORY set in which case
- * we are advised to follow the entry if it is a link or to make sure that
- * it is a directory. But since the kernel itself checks these possibilities
- * later on, we shouldn't have to do it until later. Perhaps in the future..
+/*
+ * Validate a dentry. Return 1 if unchanged, 0 if VFS layer should re-evaluate.
*
- * The code here assumes that on entry the global lock is not held
+ * @param[in] pvcp vcache for the parent directory containing 'dp'
+ * @param[in] name the name of the directory entry for 'dp'
+ * @param[in] dp the dentry we are checking
*/
static int
-#if defined(DOP_REVALIDATE_TAKES_UNSIGNED)
-afs_linux_dentry_revalidate(struct dentry *dp, unsigned int flags)
-#elif defined(DOP_REVALIDATE_TAKES_NAMEIDATA)
-afs_linux_dentry_revalidate(struct dentry *dp, struct nameidata *nd)
-#else
-afs_linux_dentry_revalidate(struct dentry *dp, int flags)
-#endif
+dentry_revalidate_common(struct vcache *pvcp, const char *name, struct dentry *dp)
{
cred_t *credp = NULL;
- struct vcache *vcp, *pvcp, *tvc = NULL;
- struct dentry *parent;
+ struct vcache *vcp, *tvc = NULL;
int valid;
struct afs_fakestat_state fakestate;
int force_drop = 0;
afs_uint32 parent_dv;
int code = 0;
-#ifdef LOOKUP_RCU
- /* We don't support RCU path walking */
-# if defined(DOP_REVALIDATE_TAKES_UNSIGNED)
- if (flags & LOOKUP_RCU)
-# else
- if (nd->flags & LOOKUP_RCU)
-# endif
- return -ECHILD;
-#endif
-
#ifdef D_SPLICE_ALIAS_RACE
if (check_dentry_race(dp)) {
valid = 0;
@@ -1446,7 +1427,7 @@ afs_linux_dentry_revalidate(struct dentry *dp, int flags)
if (code) {
goto error;
}
- if ((strcmp(dp->d_name.name, ".directory") == 0)) {
+ if ((strcmp(name, ".directory") == 0)) {
tryEvalOnly = 1;
}
if (tryEvalOnly)
@@ -1462,13 +1443,11 @@ afs_linux_dentry_revalidate(struct dentry *dp, int flags)
goto bad_dentry;
}
}
- } else if (vcp->mvstat == AFS_MVSTAT_ROOT && *dp->d_name.name != '/') {
+ } else if (vcp->mvstat == AFS_MVSTAT_ROOT && name[0] != '/') {
osi_Assert(vcp->mvid.parent != NULL);
}
- parent = dget_parent(dp);
- pvcp = VTOAFS(parent->d_inode);
- parent_dv = parent_vcache_dv(parent->d_inode, credp);
+ parent_dv = parent_vcache_dv(AFSTOV(pvcp), credp);
/* If the parent's DataVersion has changed or the vnode
* is longer valid, we need to do a full lookup. VerifyVCache
@@ -1481,7 +1460,7 @@ afs_linux_dentry_revalidate(struct dentry *dp, int flags)
if (credp == NULL) {
credp = crref();
}
- code = afs_lookup(pvcp, (char *)dp->d_name.name, &tvc, credp);
+ code = afs_lookup(pvcp, (char *)name, &tvc, credp);
code = filter_enoent(code);
if (code == ENOENT) {
/* ENOENT is not an error here. */
@@ -1492,7 +1471,6 @@ afs_linux_dentry_revalidate(struct dentry *dp, int flags)
if (code) {
/* We couldn't perform the lookup, so we don't know if the
* dentry is valid or not. */
- dput(parent);
goto error;
}
@@ -1515,19 +1493,16 @@ afs_linux_dentry_revalidate(struct dentry *dp, int flags)
* _not_ okay. Force it to be unhashed, since the given name
* doesn't point to this file anymore.
*/
- dput(parent);
force_drop = 1;
goto bad_dentry;
}
code = afs_CreateAttr(&vattr);
if (code) {
- dput(parent);
goto error;
}
if (afs_getattr(vcp, vattr, credp)) {
- dput(parent);
afs_DestroyAttr(vattr);
code = EIO;
goto error;
@@ -1542,23 +1517,15 @@ afs_linux_dentry_revalidate(struct dentry *dp, int flags)
/* should we always update the attributes at this point? */
/* unlikely--the vcache entry hasn't changed */
- dput(parent);
-
} else {
-
/* 'dp' represents a cached negative lookup. */
- parent = dget_parent(dp);
- pvcp = VTOAFS(parent->d_inode);
- parent_dv = parent_vcache_dv(parent->d_inode, credp);
+ parent_dv = parent_vcache_dv(AFSTOV(pvcp), credp);
if (parent_dv > dp->d_time || !(pvcp->f.states & CStatd)
|| afs_IsDynroot(pvcp)) {
- dput(parent);
goto bad_dentry;
}
-
- dput(parent);
}
good_dentry:
@@ -1634,6 +1601,41 @@ afs_linux_dentry_revalidate(struct dentry *dp, int flags)
#endif
}
+#if defined(DOP_REVALIDATE_TAKES_UNSIGNED)
+static int
+afs_linux_dentry_revalidate(struct dentry *dp, unsigned int flags)
+#elif defined(DOP_REVALIDATE_TAKES_NAMEIDATA)
+static int
+afs_linux_dentry_revalidate(struct dentry *dp, struct nameidata *nd)
+#else
+static int
+afs_linux_dentry_revalidate(struct dentry *dp, int flags)
+#endif
+{
+ int code;
+ struct dentry *parent;
+
+#ifdef LOOKUP_RCU
+ /* We don't support RCU path walking */
+# if defined(DOP_REVALIDATE_TAKES_UNSIGNED)
+ if ((flags & LOOKUP_RCU) != 0) {
+ return -ECHILD;
+ }
+# else
+ if ((nd->flags & LOOKUP_RCU) != 0) {
+ return -ECHILD;
+ }
+# endif
+#endif
+
+ parent = dget_parent(dp);
+ code = dentry_revalidate_common(VTOAFS(parent->d_inode),
+ dp->d_name.name, dp);
+ dput(parent);
+
+ return code;
+}
+
static void
afs_dentry_iput(struct dentry *dp, struct inode *ip)
{
--
2.49.0
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