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authorAl Viro <viro@zeniv.linux.org.uk>2008-12-30 01:48:21 -0500
committerAl Viro <viro@zeniv.linux.org.uk>2008-12-31 18:07:43 -0500
commit261bca86ed4f7f391d1938167624e78da61dcc6b (patch)
tree4601cf090fbfec31fbd554a27c67c717a7caba4b
parent272eb01485dda98e3b8910c7c1a53d597616b0a0 (diff)
downloadop-kernel-dev-261bca86ed4f7f391d1938167624e78da61dcc6b.zip
op-kernel-dev-261bca86ed4f7f391d1938167624e78da61dcc6b.tar.gz
nfsd/create race fixes, infrastructure
new helpers - insert_inode_locked() and insert_inode_locked4(). Hash new inode, making sure that there's no such inode in icache already. If there is and it does not end up unhashed (as would happen if we have nfsd trying to resolve a bogus fhandle), fail. Otherwise insert our inode into hash and succeed. In either case have i_state set to new+locked; cleanup ends up being simpler with such calling conventions. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
-rw-r--r--fs/inode.c59
-rw-r--r--include/linux/fs.h2
2 files changed, 61 insertions, 0 deletions
diff --git a/fs/inode.c b/fs/inode.c
index 098a244..7de1cda 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1032,6 +1032,65 @@ struct inode *iget_locked(struct super_block *sb, unsigned long ino)
EXPORT_SYMBOL(iget_locked);
+int insert_inode_locked(struct inode *inode)
+{
+ struct super_block *sb = inode->i_sb;
+ ino_t ino = inode->i_ino;
+ struct hlist_head *head = inode_hashtable + hash(sb, ino);
+ struct inode *old;
+
+ inode->i_state |= I_LOCK|I_NEW;
+ while (1) {
+ spin_lock(&inode_lock);
+ old = find_inode_fast(sb, head, ino);
+ if (likely(!old)) {
+ hlist_add_head(&inode->i_hash, head);
+ spin_unlock(&inode_lock);
+ return 0;
+ }
+ __iget(old);
+ spin_unlock(&inode_lock);
+ wait_on_inode(old);
+ if (unlikely(!hlist_unhashed(&old->i_hash))) {
+ iput(old);
+ return -EBUSY;
+ }
+ iput(old);
+ }
+}
+
+EXPORT_SYMBOL(insert_inode_locked);
+
+int insert_inode_locked4(struct inode *inode, unsigned long hashval,
+ int (*test)(struct inode *, void *), void *data)
+{
+ struct super_block *sb = inode->i_sb;
+ struct hlist_head *head = inode_hashtable + hash(sb, hashval);
+ struct inode *old;
+
+ inode->i_state |= I_LOCK|I_NEW;
+
+ while (1) {
+ spin_lock(&inode_lock);
+ old = find_inode(sb, head, test, data);
+ if (likely(!old)) {
+ hlist_add_head(&inode->i_hash, head);
+ spin_unlock(&inode_lock);
+ return 0;
+ }
+ __iget(old);
+ spin_unlock(&inode_lock);
+ wait_on_inode(old);
+ if (unlikely(!hlist_unhashed(&old->i_hash))) {
+ iput(old);
+ return -EBUSY;
+ }
+ iput(old);
+ }
+}
+
+EXPORT_SYMBOL(insert_inode_locked4);
+
/**
* __insert_inode_hash - hash an inode
* @inode: unhashed inode
diff --git a/include/linux/fs.h b/include/linux/fs.h
index be16ce0..e2170ee 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1902,6 +1902,8 @@ extern struct inode *ilookup(struct super_block *sb, unsigned long ino);
extern struct inode * iget5_locked(struct super_block *, unsigned long, int (*test)(struct inode *, void *), int (*set)(struct inode *, void *), void *);
extern struct inode * iget_locked(struct super_block *, unsigned long);
+extern int insert_inode_locked4(struct inode *, unsigned long, int (*test)(struct inode *, void *), void *);
+extern int insert_inode_locked(struct inode *);
extern void unlock_new_inode(struct inode *);
extern void __iget(struct inode * inode);
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