From: Miklos Szeredi <mszeredi@xxxxxxx>
Allow filesystem to select which cases it wants to perform atomic_open.
Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxx>
---
fs/namei.c | 16 +++++++++++++++-
include/linux/fs.h | 2 ++
2 files changed, 17 insertions(+), 1 deletions(-)
diff --git a/fs/namei.c b/fs/namei.c
index 835dcf1..8dfbe45 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2227,6 +2227,20 @@ look_up:
return NULL;
}
+static bool is_atomic_lookup_open(struct inode *dir, struct nameidata *nd)
+{
+ int fs_flags;
+
+ if (!(nd->flags & LOOKUP_OPEN) || !dir->i_op->atomic_open)
+ return false;
+
+ fs_flags = dir->i_sb->s_type->fs_flags;
+ if (nd->flags & LOOKUP_CREATE)
+ return !(fs_flags & FS_NO_LOOKUP_CREATE);
+ else
+ return !(fs_flags & FS_NO_LOOKUP_OPEN);
+}
+
/*
* Lookup and possibly open (and create) the last component
*
@@ -2253,7 +2267,7 @@ static struct file *lookup_open(struct nameidata *nd, struct path *path,
if (!need_lookup && dentry->d_inode)
goto out_no_open;
- if ((nd->flags & LOOKUP_OPEN) && dir_inode->i_op->atomic_open) {
+ if (is_atomic_lookup_open(dir_inode, nd)) {
struct file *filp;
filp = atomic_open(nd, dentry, op, want_write, &create_error);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 3a47ecd..6615355 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -181,6 +181,8 @@ struct inodes_stat_t {
#define FS_RENAME_DOES_D_MOVE 32768 /* FS will handle d_move()
* during rename() internally.
*/
+#define FS_NO_LOOKUP_OPEN 0x10000 /* fs can't do atomic lookup+open */
+#define FS_NO_LOOKUP_CREATE 0x20000 /* fs can't do lookup+create+open */
/*
* These are the fs-independent mount-flags: up to 32 flags are supported
--
1.7.7
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