[PATCH v7 01/12] fs/namei.c: use trailing_slashes()

[Jori Koolstra <jkoolstra@xs4all.nl>]

There are several places in fs/namei.c that can use the
trailing_slashes() function to improve context. To allow this broader
use its signature is changed to take a struct qstr instead of a struct
nameidata.

Reviewed-by: NeilBrown <neil@brown.name>
Signed-off-by: Jori Koolstra <jkoolstra@xs4all.nl>
---
 fs/namei.c | 28 +++++++++++++++-------------
 1 file changed, 15 insertions(+), 13 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index c87c14ee1a25..839258260ad5 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2810,9 +2810,16 @@ static const char *path_init(struct nameidata *nd, unsigned flags)
 	return s;
 }
 
+static inline bool trailing_slashes(const struct qstr *last)
+{
+	/* last->len is set by hash_name() to the length of the current
+	 * component ->name, terminating with '/' or a NUL character. */
+	return (bool)last->name[last->len];
+}
+
 static inline const char *lookup_last(struct nameidata *nd)
 {
-	if (nd->last_type == LAST_NORM && nd->last.name[nd->last.len])
+	if (nd->last_type == LAST_NORM && trailing_slashes(&nd->last))
 		nd->flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
 
 	return walk_component(nd, WALK_TRAILING);
@@ -4724,17 +4731,12 @@ struct file *vfs_lookup_open(struct path *parent, struct qstr *last,
 }
 EXPORT_SYMBOL_FOR_MODULES(vfs_lookup_open, "nfsd");
 
-static inline bool trailing_slashes(struct nameidata *nd)
-{
-	return (bool)nd->last.name[nd->last.len];
-}
-
 static struct dentry *lookup_fast_for_open(struct nameidata *nd, int open_flag)
 {
 	struct dentry *dentry;
 
 	if (open_flag & O_CREAT) {
-		if (trailing_slashes(nd))
+		if (trailing_slashes(&nd->last))
 			return ERR_PTR(-EISDIR);
 
 		/* Don't bother on an O_EXCL create */
@@ -4742,7 +4744,7 @@ static struct dentry *lookup_fast_for_open(struct nameidata *nd, int open_flag)
 			return NULL;
 	}
 
-	if (trailing_slashes(nd))
+	if (trailing_slashes(&nd->last))
 		nd->flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
 
 	dentry = lookup_fast(nd);
@@ -5116,7 +5118,7 @@ static struct dentry *filename_create(int dfd, struct filename *name,
 	 * Do the final lookup.  Suppress 'create' if there is a trailing
 	 * '/', and a directory wasn't requested.
 	 */
-	if (last.name[last.len] && !want_dir)
+	if (trailing_slashes(&last) && !want_dir)
 		create_flags &= ~LOOKUP_CREATE;
 	dentry = start_dirop(path->dentry, &last, reval_flag | create_flags);
 	if (IS_ERR(dentry))
@@ -5732,7 +5734,7 @@ int filename_unlinkat(int dfd, struct filename *name)
 		goto exit_drop_write;
 
 	/* Why not before? Because we want correct error value */
-	if (unlikely(last.name[last.len])) {
+	if (unlikely(trailing_slashes(&last))) {
 		if (d_is_dir(dentry))
 			error = -EISDIR;
 		else
@@ -6334,16 +6336,16 @@ int filename_renameat2(int olddfd, struct filename *from,
 	if (flags & RENAME_EXCHANGE) {
 		if (!d_is_dir(rd.new_dentry)) {
 			error = -ENOTDIR;
-			if (new_last.name[new_last.len])
+			if (trailing_slashes(&new_last))
 				goto exit_unlock;
 		}
 	}
 	/* unless the source is a directory trailing slashes give -ENOTDIR */
 	if (!d_is_dir(rd.old_dentry)) {
 		error = -ENOTDIR;
-		if (old_last.name[old_last.len])
+		if (trailing_slashes(&old_last))
 			goto exit_unlock;
-		if (!(flags & RENAME_EXCHANGE) && new_last.name[new_last.len])
+		if (!(flags & RENAME_EXCHANGE) && trailing_slashes(&new_last))
 			goto exit_unlock;
 	}
 
-- 
2.56.0