LU-12137 osd-ldiskfs: create locked and unlocked versions of osd lookup code

[fs/lustre-release.git] / lustre / osd-ldiskfs / osd_compat.c

diff --git a/lustre/osd-ldiskfs/osd_compat.c b/lustre/osd-ldiskfs/osd_compat.c
index 298ce2f..15c395f 100644 (file)
--- a/lustre/osd-ldiskfs/osd_compat.c
+++ b/lustre/osd-ldiskfs/osd_compat.c
@@ -66,27 +66,32 @@ static void osd_push_ctxt(const struct osd_device *dev,
        push_ctxt(save, newctxt);
 }
 
-/**
- * osd_lookup_one_len_unlocked
- *
- * @dev:       obd device we are searching
- * @name:      pathname component to lookup
- * @base:      base directory to lookup from
- * @len:       maximum length @len should be interpreted to
- *
- * This should be called without the parent
- * i_mutex held, and will take the i_mutex itself.
- */
-struct dentry *osd_lookup_one_len_unlocked(struct osd_device *dev,
-                                          const char *name,
-                                          struct dentry *base, int len)
+struct dentry *osd_lookup_one_len_common(struct osd_device *dev,
+                                        const char *name,
+                                        struct dentry *base, int len,
+                                        enum oi_check_flags flags)
 {
        struct dentry *dchild;
 
-       inode_lock(base->d_inode);
-       dchild = lookup_one_len(name, base, len);
-       inode_unlock(base->d_inode);
-
+       /*
+        * We can't use inode_is_locked() directly since we can't know
+        * if the current thread context took the lock earlier or if
+        * another thread context took the lock. OI_LOCKED tells us
+        * if the current thread context has already taken the lock.
+        */
+       if (!(flags & OI_LOCKED)) {
+               /* If another thread took this lock already we will
+                * just have to wait until the other thread is done.
+                */
+               inode_lock(base->d_inode);
+               dchild = lookup_one_len(name, base, len);
+               inode_unlock(base->d_inode);
+       } else {
+               /* This thread context already has taken the lock.
+                * Other threads will have to wait until we are done.
+                */
+               dchild = lookup_one_len(name, base, len);
+       }
        if (IS_ERR(dchild))
                return dchild;
 
@@ -102,17 +107,37 @@ struct dentry *osd_lookup_one_len_unlocked(struct osd_device *dev,
 }
 
 /**
- * osd_ios_lookup_one_len - lookup single pathname component
+ * osd_lookup_one_len_unlocked
+ *
+ * @dev:       obd device we are searching
+ * @name:      pathname component to lookup
+ * @base:      base directory to lookup from
+ * @len:       maximum length @len should be interpreted to
+ *
+ * Unlike osd_lookup_one_len, this should be called without the parent
+ * i_mutex held, and will take the i_mutex itself.
+ */
+struct dentry *osd_lookup_one_len_unlocked(struct osd_device *dev,
+                                          const char *name,
+                                          struct dentry *base, int len)
+{
+       return osd_lookup_one_len_common(dev, name, base, len, ~OI_LOCKED);
+}
+
+/**
+ * osd_lookup_one_len - lookup single pathname component
  *
  * @dev:       obd device we are searching
  * @name:      pathname component to lookup
  * @base:      base directory to lookup from
  * @len:       maximum length @len should be interpreted to
+ *
+ * The caller must hold inode lock
  */
-struct dentry *osd_ios_lookup_one_len(struct osd_device *dev, const char *name,
-                                     struct dentry *base, int len)
+struct dentry *osd_lookup_one_len(struct osd_device *dev, const char *name,
+                                 struct dentry *base, int len)
 {
-       return osd_lookup_one_len_unlocked(dev, name, base, len);
+       return osd_lookup_one_len_common(dev, name, base, len, OI_LOCKED);
 }
 
 /* utility to make a directory */