[PATCH 3/3] server: When renaming, only fstat the source once.

[Gabriel Ivăncescu]

From: Gabriel Ivăncescu

This avoids unnecessary fstat() calls on the source fd, and also fixes a
bug if fstat ever fails where checking if source is a directory, although
that's unlikely.

Signed-off-by: Gabriel Ivăncescu 
---
 server/fd.c | 27 +++++++++++++++++----------
 1 file changed, 17 insertions(+), 10 deletions(-)

diff --git a/server/fd.c b/server/fd.c
index 786f5e0bbf9..9314df19b7b 100644
--- a/server/fd.c
+++ b/server/fd.c
@@ -2525,8 +2525,9 @@ static void set_fd_disposition( struct fd *fd, unsigned int flags )
 static void set_fd_name( struct fd *fd, struct fd *root, const char *nameptr, data_size_t len,
                          struct unicode_str nt_name, int create_link, unsigned int flags )
 {
+    struct stat st, src_st;
+    int src_st_filled = 0;
     struct inode *inode;
-    struct stat st, st2;
     char *name;
     const unsigned int replace = flags & FILE_RENAME_REPLACE_IF_EXISTS;

@@ -2563,15 +2564,21 @@ static void set_fd_name( struct fd *fd, struct fd *root, const char *nameptr, da
     }

/* when creating a hard link, source cannot be a dir */
-    if (create_link && !fstat( fd->unix_fd, &st ) && S_ISDIR( st.st_mode ))
+    if (create_link && !fstat( fd->unix_fd, &src_st ))
     {
-        set_error( STATUS_FILE_IS_A_DIRECTORY );
-        goto failed;
+        src_st_filled = 1;
+        if (S_ISDIR( src_st.st_mode ))
+        {
+            set_error( STATUS_FILE_IS_A_DIRECTORY );
+            goto failed;
+        }
     }

if (!stat( name, &st ))
     {
-        if (!fstat( fd->unix_fd, &st2 ) && st.st_ino == st2.st_ino && st.st_dev == st2.st_dev)
+        if (!src_st_filled && !fstat( fd->unix_fd, &src_st ))
+            src_st_filled = 1;
+        if (src_st_filled && st.st_ino == src_st.st_ino && st.st_dev == src_st.st_dev)
         {
             if (!create_link)
             {
@@ -2621,7 +2628,7 @@ 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 || (src_st_filled && S_ISDIR( src_st.st_mode )))
         {
             if (unlink( name ))
             {
@@ -2645,14 +2652,14 @@ static void set_fd_name( struct fd *fd, struct fd *root, const char *nameptr, da
         goto failed;
     }

-    if (is_file_executable( fd->unix_name ) != is_file_executable( name ) && !fstat( fd->unix_fd, &st ))
+    if (is_file_executable( fd->unix_name ) != is_file_executable( name ) && (src_st_filled || !fstat( fd->unix_fd, &src_st )))
     {
         if (is_file_executable( name ))
             /* set executable bit where read bit is set */
-            st.st_mode |= (st.st_mode & 0444) >> 2;
+            src_st.st_mode |= (src_st.st_mode & 0444) >> 2;
         else
-            st.st_mode &= ~0111;
-        fchmod( fd->unix_fd, st.st_mode );
+            src_st.st_mode &= ~0111;
+        fchmod( fd->unix_fd, src_st.st_mode );
     }

free( fd->nt_name );