[PATCH v7 4/5] server: Avoid fstat when comparing inode/device for renaming.

[Gabriel Ivăncescu]

From: Gabriel Ivăncescu

The first fstat on the source happens for create_link only, so the new one
isn't redundant in that case, but reduces syscalls in case of links.

Signed-off-by: Gabriel Ivăncescu 
---
 server/fd.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/server/fd.c b/server/fd.c
index 5fc994cf2dd..5ccca271b8a 100644
--- a/server/fd.c
+++ b/server/fd.c
@@ -2641,7 +2641,7 @@ static void set_fd_name( struct fd *fd, struct fd *root, const char *nameptr, da
                          struct unicode_str nt_name, int create_link, unsigned int flags )
 {
     struct inode *inode;
-    struct stat st, st2;
+    struct stat st;
     char *name;
     const unsigned int replace = flags & FILE_RENAME_REPLACE_IF_EXISTS;

@@ -2691,7 +2691,7 @@ static void set_fd_name( struct fd *fd, struct fd *root, const char *nameptr, da

if (!stat( name, &st ))
     {
-        if (!fstat( fd->unix_fd, &st2 ) && st.st_ino == st2.st_ino && st.st_dev == st2.st_dev)
+        if (st.st_ino == fd->inode->ino && st.st_dev == fd->inode->device->dev)
         {
             if (!create_link) rename_same_file( fd->unix_name, name, S_ISDIR( st.st_mode ) );
             else if (!replace) set_error( STATUS_OBJECT_NAME_COLLISION );
@@ -2734,7 +2734,7 @@ static void set_fd_name( struct fd *fd, struct fd *root, const char *nameptr, da

/* link() expects that the target doesn't exist */
         /* rename() cannot replace files with directories */
-        if (create_link || S_ISDIR( st2.st_mode ))
+        if (create_link || (!fstat( fd->unix_fd, &st ) && S_ISDIR( st.st_mode )))
         {
             if (unlink( name ))
             {