fs: change d_compare for rcu-walk
Change d_compare so it may be called from lock-free RCU lookups. This
does put significant restrictions on what may be done from the callback,
however there don't seem to have been any problems with in-tree fses.
If some strange use case pops up that _really_ cannot cope with the
rcu-walk rules, we can just add new rcu-unaware callbacks, which would
cause name lookup to drop out of rcu-walk mode.
For in-tree filesystems, this is just a mechanical change.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
diff --git a/fs/affs/namei.c b/fs/affs/namei.c
index 914d1c0..547d5de 100644
--- a/fs/affs/namei.c
+++ b/fs/affs/namei.c
@@ -14,10 +14,16 @@
static int affs_toupper(int ch);
static int affs_hash_dentry(struct dentry *, struct qstr *);
-static int affs_compare_dentry(struct dentry *, struct qstr *, struct qstr *);
+static int affs_compare_dentry(const struct dentry *parent,
+ const struct inode *pinode,
+ const struct dentry *dentry, const struct inode *inode,
+ unsigned int len, const char *str, const struct qstr *name);
static int affs_intl_toupper(int ch);
static int affs_intl_hash_dentry(struct dentry *, struct qstr *);
-static int affs_intl_compare_dentry(struct dentry *, struct qstr *, struct qstr *);
+static int affs_intl_compare_dentry(const struct dentry *parent,
+ const struct inode *pinode,
+ const struct dentry *dentry, const struct inode *inode,
+ unsigned int len, const char *str, const struct qstr *name);
const struct dentry_operations affs_dentry_operations = {
.d_hash = affs_hash_dentry,
@@ -88,29 +94,29 @@
return __affs_hash_dentry(dentry, qstr, affs_intl_toupper);
}
-static inline int
-__affs_compare_dentry(struct dentry *dentry, struct qstr *a, struct qstr *b, toupper_t toupper)
+static inline int __affs_compare_dentry(unsigned int len,
+ const char *str, const struct qstr *name, toupper_t toupper)
{
- const u8 *aname = a->name;
- const u8 *bname = b->name;
- int len;
+ const u8 *aname = str;
+ const u8 *bname = name->name;
- /* 'a' is the qstr of an already existing dentry, so the name
- * must be valid. 'b' must be validated first.
+ /*
+ * 'str' is the name of an already existing dentry, so the name
+ * must be valid. 'name' must be validated first.
*/
- if (affs_check_name(b->name,b->len))
+ if (affs_check_name(name->name, name->len))
return 1;
- /* If the names are longer than the allowed 30 chars,
+ /*
+ * If the names are longer than the allowed 30 chars,
* the excess is ignored, so their length may differ.
*/
- len = a->len;
if (len >= 30) {
- if (b->len < 30)
+ if (name->len < 30)
return 1;
len = 30;
- } else if (len != b->len)
+ } else if (len != name->len)
return 1;
for (; len > 0; len--)
@@ -121,14 +127,18 @@
}
static int
-affs_compare_dentry(struct dentry *dentry, struct qstr *a, struct qstr *b)
+affs_compare_dentry(const struct dentry *parent, const struct inode *pinode,
+ const struct dentry *dentry, const struct inode *inode,
+ unsigned int len, const char *str, const struct qstr *name)
{
- return __affs_compare_dentry(dentry, a, b, affs_toupper);
+ return __affs_compare_dentry(len, str, name, affs_toupper);
}
static int
-affs_intl_compare_dentry(struct dentry *dentry, struct qstr *a, struct qstr *b)
+affs_intl_compare_dentry(const struct dentry *parent,const struct inode *pinode,
+ const struct dentry *dentry, const struct inode *inode,
+ unsigned int len, const char *str, const struct qstr *name)
{
- return __affs_compare_dentry(dentry, a, b, affs_intl_toupper);
+ return __affs_compare_dentry(len, str, name, affs_intl_toupper);
}
/*