The patch titled
jfs: don't overwrite dentry name in d_revalidate
has been added to the -mm tree. Its filename is
jfs-dont-overwrite-dentry-name-in-d_revalidate.patch
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------------------------------------------------------
Subject: jfs: don't overwrite dentry name in d_revalidate
From: Nick Piggin <npiggin@xxxxxxxxx>
Instead use fatfs's method for dealing with negative dentries to
preserve case, rather than overwrite dentry name in d_revalidate, which
is a bit ugly and also gets in the way of doing lock-free path walking.
Signed-off-by: Nick Piggin <npiggin@xxxxxxxxx>
Cc: Dave Kleikamp <shaggy@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/jfs/namei.c | 43 +++++++++++++++++++++++++++++++++++--------
1 file changed, 35 insertions(+), 8 deletions(-)
diff -puN fs/jfs/namei.c~jfs-dont-overwrite-dentry-name-in-d_revalidate fs/jfs/namei.c
--- a/fs/jfs/namei.c~jfs-dont-overwrite-dentry-name-in-d_revalidate
+++ a/fs/jfs/namei.c
@@ -18,6 +18,7 @@
*/
#include <linux/fs.h>
+#include <linux/namei.h>
#include <linux/ctype.h>
#include <linux/quotaops.h>
#include <linux/exportfs.h>
@@ -1597,21 +1598,47 @@ static int jfs_ci_compare(struct dentry
goto out;
}
result = 0;
+out:
+ return result;
+}
+static int jfs_ci_revalidate(struct dentry *dentry, struct nameidata *nd)
+{
/*
- * We want creates to preserve case. A negative dentry, a, that
- * has a different case than b may cause a new entry to be created
- * with the wrong case. Since we can't tell if a comes from a negative
- * dentry, we blindly replace it with b. This should be harmless if
- * a is not a negative dentry.
+ * This is not negative dentry. Always valid.
+ *
+ * Note, rename() to existing directory entry will have ->d_inode,
+ * and will use existing name which isn't specified name by user.
+ *
+ * We may be able to drop this positive dentry here. But dropping
+ * positive dentry isn't good idea. So it's unsupported like
+ * rename("filename", "FILENAME") for now.
*/
- memcpy((unsigned char *)a->name, b->name, a->len);
-out:
- return result;
+ if (dentry->d_inode)
+ return 1;
+
+ /*
+ * This may be nfsd (or something), anyway, we can't see the
+ * intent of this. So, since this can be for creation, drop it.
+ */
+ if (!nd)
+ return 0;
+
+ /*
+ * Drop the negative dentry, in order to make sure to use the
+ * case sensitive name which is specified by user if this is
+ * for creation.
+ */
+ if (!(nd->flags & (LOOKUP_CONTINUE | LOOKUP_PARENT))) {
+ if (nd->flags & (LOOKUP_CREATE | LOOKUP_RENAME_TARGET))
+ return 0;
+ }
+ return 1;
}
const struct dentry_operations jfs_ci_dentry_operations =
{
.d_hash = jfs_ci_hash,
.d_compare = jfs_ci_compare,
+ .d_revalidate = jfs_ci_revalidate,
};
_
Patches currently in -mm which might be from npiggin@xxxxxxxxx are
atomic-add-atomic_inc_not_zero_hint.patch
linux-next.patch
radix-tree-fix-rcu-bug.patch
cifs-dont-overwrite-dentry-name-in-d_revalidate.patch
jfs-dont-overwrite-dentry-name-in-d_revalidate.patch
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