[RFC][PATCH v3 38/55] split the lookup-related parts of do_last() into a separate helper

Al Viro
2020-03-01T21:53:01Z

fs/namei.c | 51 +++++++++++++++++++++++++++++----------------------
1 file changed, 29 insertions(+), 22 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 66f236d5aee7..b73ff6dcca24 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3117,19 +3117,12 @@ static struct dentry *lookup_open(struct nameidata *nd, struct file *file,
return ERR_PTR(error);
}

-/*
- * Handle the last step of open()
- */
-static const char *do_last(struct nameidata *nd,
+static const char *open_last_lookups(struct nameidata *nd,
struct file *file, const struct open_flags *op)
{
struct dentry *dir = nd->path.dentry;
- kuid_t dir_uid = nd->inode->i_uid;
- umode_t dir_mode = nd->inode->i_mode;
int open_flag = op->open_flag;
- bool do_truncate;
bool got_write = false;
- int acc_mode;
unsigned seq;
struct inode *inode;
struct dentry *dentry;
@@ -3141,9 +3134,9 @@ static const char *do_last(struct nameidata *nd,

if (nd->last_type != LAST_NORM) {
error = handle_dots(nd, nd->last_type);
- if (unlikely(error))
- return ERR_PTR(error);
- goto finish_open;
+ if (likely(!error))
+ error = complete_walk(nd);
+ return ERR_PTR(error);
}

if (!(open_flag & O_CREAT)) {
@@ -3156,7 +3149,6 @@ static const char *do_last(struct nameidata *nd,
if (likely(dentry))
goto finish_lookup;

- BUG_ON(nd->inode != dir->d_inode);
BUG_ON(nd->flags & LOOKUP_RCU);
} else {
/* create side of things */
@@ -3166,7 +3158,7 @@ static const char *do_last(struct nameidata *nd,
* about to look up
*/
error = complete_walk(nd);
- if (error)
+ if (unlikely(error))
return ERR_PTR(error);

audit_inode(nd->name, dir, AUDIT_INODE_PARENT);
@@ -3195,10 +3187,8 @@ static const char *do_last(struct nameidata *nd,
else
inode_unlock_shared(dir->d_inode);

- if (got_write) {
+ if (got_write)
mnt_drop_write(nd->path.mnt);
- got_write = false;
- }

if (IS_ERR(dentry))
return ERR_CAST(dentry);
@@ -3206,7 +3196,7 @@ static const char *do_last(struct nameidata *nd,
if (file->f_mode & (FMODE_OPENED | FMODE_CREATED)) {
dput(nd->path.dentry);
nd->path.dentry = dentry;
- goto finish_open_created;
+ return NULL;
}

finish_lookup:
@@ -3221,12 +3211,29 @@ static const char *do_last(struct nameidata *nd,
audit_inode(nd->name, nd->path.dentry, 0);
return ERR_PTR(-EEXIST);
}
-finish_open:
+
/* Why this, you ask? _Now_ we might have grown LOOKUP_JUMPED... */
- error = complete_walk(nd);
- if (error)
- return ERR_PTR(error);
-finish_open_created:
+ return ERR_PTR(complete_walk(nd));
+}
+
+/*
+ * Handle the last step of open()
+ */
+static const char *do_last(struct nameidata *nd,
+ struct file *file, const struct open_flags *op)
+{
+ kuid_t dir_uid = nd->inode->i_uid;
+ umode_t dir_mode = nd->inode->i_mode;
+ int open_flag = op->open_flag;
+ bool do_truncate;
+ int acc_mode;
+ const char *link;
+ int error;
+
+ link = open_last_lookups(nd, file, op);
+ if (unlikely(link))
+ return link;
+
if (!(file->f_mode & FMODE_CREATED))
audit_inode(nd->name, nd->path.dentry, 0);
if (open_flag & O_CREAT) {
--
2.11.0