fs: fat: call set_name() only once

In set_name() we select the short name. Once this is correctly implemented
this will be a performance intensive operation because we need to check
that the name does not exist yet. So set_name should only be called once.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

diff --git a/fs/fat/fat_write.c b/fs/fat/fat_write.c
index 7e8886791cc64116938cea0c1c0793c7771b66ed..716b6a6627d971a381c542da641164a1c2ce3ff5 100644 (file)
--- a/fs/fat/fat_write.c
+++ b/fs/fat/fat_write.c
@@ -23,6 +23,9 @@
 /* Characters that may only be used in long file names */
 static const char LONG_ONLY_CHARS[] = "+,;=[]";
 
+/* Combined size of the name and ext fields in the directory entry */
+#define SHORT_NAME_SIZE 11
+
 /**
  * str2fat() - convert string to valid FAT name characters
  *
@@ -68,24 +71,28 @@ static int str2fat(char *dest, char *src, int length)
  *
  * If a long name is needed, a short name is constructed.
  *
- * @dirent:    directory entry
  * @filename:  long file name
+ * @shortname: buffer of 11 bytes to receive chosen short name and extension
  * Return:     number of directory entries needed, negative on error
  */
-static int set_name(dir_entry *dirent, const char *filename)
+static int set_name(const char *filename, char *shortname)
 {
        char *period;
        char *pos;
        int period_location;
        char buf[13];
        int i;
+       int ret;
+       struct {
+               char name[8];
+               char ext[3];
+       } dirent;
 
        if (!filename)
                return -EIO;
 
-       /* Initialize buffers */
-       memset(dirent->name, ' ', sizeof(dirent->name));
-       memset(dirent->ext, ' ', sizeof(dirent->ext));
+       /* Initialize buffer */
+       memset(&dirent, ' ', sizeof(dirent));
 
        /* Convert filename to upper case short name */
        period = strrchr(filename, '.');
@@ -95,20 +102,22 @@ static int set_name(dir_entry *dirent, const char *filename)
                period = 0;
        }
        if (period)
-               str2fat(dirent->ext, period + 1, sizeof(dirent->ext));
-       period_location = str2fat(dirent->name, pos, sizeof(dirent->name));
+               str2fat(dirent.ext, period + 1, sizeof(dirent.ext));
+       period_location = str2fat(dirent.name, pos, sizeof(dirent.name));
        if (period_location < 0)
                return period_location;
-       if (*dirent->name == ' ')
-               *dirent->name = '_';
+       if (*dirent.name == ' ')
+               *dirent.name = '_';
        /* 0xe5 signals a deleted directory entry. Replace it by 0x05. */
-       if (*dirent->name == 0xe5)
-               *dirent->name = 0x05;
+       if (*dirent.name == 0xe5)
+               *dirent.name = 0x05;
 
        /* If filename and short name are the same, quit. */
-       sprintf(buf, "%.*s.%.3s", period_location, dirent->name, dirent->ext);
-       if (!strcmp(buf, filename))
-               return 1;
+       sprintf(buf, "%.*s.%.3s", period_location, dirent.name, dirent.ext);
+       if (!strcmp(buf, filename)) {
+               ret = 1;
+               goto out;
+       }
 
        /* Construct an indexed short name */
        for (i = 1; i < 0x200000; ++i) {
@@ -128,20 +137,24 @@ static int set_name(dir_entry *dirent, const char *filename)
                suffix_start = 8 - suffix_len;
                if (suffix_start > period_location)
                        suffix_start = period_location;
-               memcpy(dirent->name + suffix_start, buf, suffix_len);
-               if (*dirent->ext != ' ')
+               memcpy(dirent.name + suffix_start, buf, suffix_len);
+               if (*dirent.ext != ' ')
                        sprintf(buf, "%.*s.%.3s", suffix_start + suffix_len,
-                               dirent->name, dirent->ext);
+                               dirent.name, dirent.ext);
                else
                        sprintf(buf, "%.*s", suffix_start + suffix_len,
-                               dirent->name);
+                               dirent.name);
                debug("short name: %s\n", buf);
                /* TODO: Check that the short name does not exist yet. */
 
                /* Each long name directory entry takes 13 characters. */
-               return (strlen(filename) + 25) / 13;
+               ret = (strlen(filename) + 25) / 13;
+               goto out;
        }
        return -EIO;
+out:
+       memcpy(shortname, dirent.name, SHORT_NAME_SIZE);
+       return ret;
 }
 
 static int total_sector;
@@ -1019,18 +1032,27 @@ getit:
        return 0;
 }
 
-/*
- * Fill dir_entry
+/**
+ * fill_dentry() - fill directory entry with shortname
+ *
+ * @mydata:            private filesystem parameters
+ * @dentptr:           directory entry
+ * @shortname:         chosen short name
+ * @start_cluster:     first cluster of file
+ * @size:              file size
+ * @attr:              file attributes
  */
 static void fill_dentry(fsdata *mydata, dir_entry *dentptr,
-       const char *filename, __u32 start_cluster, __u32 size, __u8 attr)
+       const char *shortname, __u32 start_cluster, __u32 size, __u8 attr)
 {
+       memset(dentptr, 0, sizeof(*dentptr));
+
        set_start_cluster(mydata, dentptr, start_cluster);
        dentptr->size = cpu_to_le32(size);
 
        dentptr->attr = attr;
 
-       set_name(dentptr, filename);
+       memcpy(dentptr->name, shortname, SHORT_NAME_SIZE);
 }
 
 /*
@@ -1215,6 +1237,7 @@ int file_fat_write_at(const char *filename, loff_t pos, void *buffer,
                retdent->size = cpu_to_le32(pos + size);
        } else {
                /* Create a new file */
+               char shortname[SHORT_NAME_SIZE];
 
                if (itr->is_root) {
                        /* root dir cannot have "." or ".." */
@@ -1237,21 +1260,19 @@ int file_fat_write_at(const char *filename, loff_t pos, void *buffer,
                        goto exit;
                }
 
-               memset(itr->dent, 0, sizeof(*itr->dent));
-
                /* Check if long name is needed */
-               ret = set_name(itr->dent, filename);
+               ret = set_name(filename, shortname);
                if (ret < 0)
                        goto exit;
                if (ret > 1) {
                        /* Set long name entries */
-                       ret = fill_dir_slot(itr, filename, itr->dent->name);
+                       ret = fill_dir_slot(itr, filename, shortname);
                        if (ret)
                                goto exit;
                }
 
                /* Set short name entry */
-               fill_dentry(itr->fsdata, itr->dent, filename, 0, size,
+               fill_dentry(itr->fsdata, itr->dent, shortname, 0, size,
                            ATTR_ARCH);
 
                retdent = itr->dent;
@@ -1484,6 +1505,8 @@ int fat_mkdir(const char *new_dirname)
                ret = -EEXIST;
                goto exit;
        } else {
+               char shortname[SHORT_NAME_SIZE];
+
                if (itr->is_root) {
                        /* root dir cannot have "." or ".." */
                        if (!strcmp(l_dirname, ".") ||
@@ -1499,21 +1522,19 @@ int fat_mkdir(const char *new_dirname)
                        goto exit;
                }
 
-               memset(itr->dent, 0, sizeof(*itr->dent));
-
                /* Check if long name is needed */
-               ret = set_name(itr->dent, dirname);
+               ret = set_name(dirname, shortname);
                if (ret < 0)
                        goto exit;
                if (ret > 1) {
                        /* Set long name entries */
-                       ret = fill_dir_slot(itr, dirname, itr->dent->name);
+                       ret = fill_dir_slot(itr, dirname, shortname);
                        if (ret)
                                goto exit;
                }
 
                /* Set attribute as archive for regular file */
-               fill_dentry(itr->fsdata, itr->dent, dirname, 0, 0,
+               fill_dentry(itr->fsdata, itr->dent, shortname, 0, 0,
                            ATTR_DIR | ATTR_ARCH);
 
                retdent = itr->dent;