Attachment 150805 Details for Bug 228801 – Keep track of the higher bits of jiffies64 in NFS dentries.

[patch] Keep track of the higher bits of jiffies64 in NFS dentries.

nfs_dentry_jiffies_overflow_2.patch (text/plain), 1.72 KB, created by Fabio Olive Leite on 2007-03-23 22:22:46 UTC

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Creator: Fabio Olive Leite

Created: 2007-03-23 22:22:46 UTC

Size: 1.72 KB

patch

obsolete

>diff -rup linux-2.6.9/fs/nfs/dir.c linux-2.6.9/fs/nfs/dir.c
>--- linux-2.6.9/fs/nfs/dir.c	2007-03-21 17:40:31.000000000 -0400
>+++ linux-2.6.9/fs/nfs/dir.c	2007-03-23 18:07:53.000000000 -0400
>@@ -616,11 +616,26 @@ static inline int nfs_check_verifier(str
> 	if ((NFS_I(dir)->cache_validity & NFS_INO_INVALID_ATTR) != 0
> 			|| nfs_attribute_timeout(dir))
> 		return 0;
>+#if (BITS_PER_LONG < 64)
>+	/* In 32bit architectures, also check the cached higher bits of
>+	 * jiffies64. NFS dentries can sit idle across two sign flips of
>+	 * 32bit jiffies and fool time_after[_eq].
>+	 */
>+	if ((u32)(dentry->d_cookie) != (u32)(get_jiffies_64() >> 32))
>+		return 0;
>+#endif
> 	return nfs_verify_change_attribute(dir, (unsigned long)dentry->d_fsdata);
> }
> 
> static inline void nfs_set_verifier(struct dentry * dentry, unsigned long verf)
> {
>+#if (BITS_PER_LONG < 64)
>+	/* In 32bit architectures we can have problems with dentries that sit
>+	 * idle during two flips of the MSB of the u32 jiffies, so we keep
>+	 * track of the higher bits in d_cookie.
>+	 */
>+	(u32)(dentry->d_cookie) = (u32)(get_jiffies_64() >> 32);
>+#endif
> 	dentry->d_fsdata = (void *)verf;
> }
> 
>@@ -702,8 +717,17 @@ static int nfs_lookup_revalidate(struct 
> 	inode = dentry->d_inode;
> 
> 	if (!inode) {
>-		if (nfs_neg_need_reval(dir, dentry, nd))
>+		if (nfs_neg_need_reval(dir, dentry, nd)) {
>+#if (BITS_PER_LONG < 64)
>+			dfprintk(VFS, "nfs_lookup_revalidate: expiring neg dentry for %s\n",
>+				dentry->d_name.name);
>+			dfprintk(VFS, "  d_cookie %08x high_jiffies %08x\n",
>+				dentry->d_cookie, (u32)(get_jiffies_64() >> 32));
>+			dfprintk(VFS, "  d_fsdata %08x cache_change_attribute %08x\n",
>+				dentry->d_fsdata, NFS_I(dir)->cache_change_attribute);
>+#endif
> 			goto out_bad;
>+		}
> 		goto out_valid;
> 	}
>

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Attachments on bug 228801: 148096 | 148097 | 148440 | 150805 | 157492 | 158367