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-rw-r--r--fs/namei.c29
1 files changed, 26 insertions, 3 deletions
diff --git a/fs/namei.c b/fs/namei.c
index ffcd4e114b6..5abab917690 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2192,6 +2192,19 @@ static int may_o_create(struct path *dir, struct dentry *dentry, umode_t mode)
return security_inode_create(dir->dentry->d_inode, dentry, mode);
}
+/*
+ * Attempt to atomically look up, create and open a file from a negative
+ * dentry.
+ *
+ * Returns 0 if successful. The file will have been created and attached to
+ * @file by the filesystem calling finish_open().
+ *
+ * Returns 1 if the file was looked up only or didn't need creating. The
+ * caller will need to perform the open themselves. @path will have been
+ * updated to point to the new dentry. This may be negative.
+ *
+ * Returns an error code otherwise.
+ */
static int atomic_open(struct nameidata *nd, struct dentry *dentry,
struct path *path, struct file *file,
const struct open_flags *op,
@@ -2336,12 +2349,22 @@ looked_up:
}
/*
- * Lookup, maybe create and open the last component
+ * Look up and maybe create and open the last component.
*
* Must be called with i_mutex held on parent.
*
- * Returns open file or NULL on success, error otherwise. NULL means no open
- * was performed, only lookup.
+ * Returns 0 if the file was successfully atomically created (if necessary) and
+ * opened. In this case the file will be returned attached to @file.
+ *
+ * Returns 1 if the file was not completely opened at this time, though lookups
+ * and creations will have been performed and the dentry returned in @path will
+ * be positive upon return if O_CREAT was specified. If O_CREAT wasn't
+ * specified then a negative dentry may be returned.
+ *
+ * An error code is returned otherwise.
+ *
+ * FILE_CREATE will be set in @*opened if the dentry was created and will be
+ * cleared otherwise prior to returning.
*/
static int lookup_open(struct nameidata *nd, struct path *path,
struct file *file,