From 621e155a3591962420eacdd39f6f0aa29ceb221e Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Fri, 7 Jan 2011 17:49:27 +1100 Subject: 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 --- fs/affs/namei.c | 46 ++++++++++++++++++++++++++++------------------ 1 file changed, 28 insertions(+), 18 deletions(-) (limited to 'fs/affs/namei.c') diff --git a/fs/affs/namei.c b/fs/affs/namei.c index 914d1c0bc07a..547d5deb0d42 100644 --- a/fs/affs/namei.c +++ b/fs/affs/namei.c @@ -14,10 +14,16 @@ typedef int (*toupper_t)(int); 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 @@ affs_intl_hash_dentry(struct dentry *dentry, struct qstr *qstr) 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 @@ __affs_compare_dentry(struct dentry *dentry, struct qstr *a, struct qstr *b, tou } 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); } /* -- cgit v1.2.3-59-g8ed1b