Re: VFAT 2.1.47

Martin von Loewis (martin@mira.isdn.cs.tu-berlin.de)
Sat, 26 Jul 1997 16:41:22 +0200

Andreas Schwab wrote:
> There is likely to be one problem that i also tripped along while porting
> msdos: you must not return ENOENT from lookup, instead only the fact that
> dentry->d_inode is NULL tells the VFS that the file does not exist. Thus
> you should change all `return -ENOENT' in vfat_lookup to `return 0'. This
> also includes the implicit ENOENT that you may get from vfat_find.

I deliberately ignored those changes, because I found it strange to return
success when an error occured. Oh well.

I've included an updated patch below. This also fixes a problem with
renaming; it would not update the dcache, but iput the parent directories.
As for renaming: In the msdos case, it seems not right to use d_move
after a rename. After all, a new inode might be created - at least in
the 'different directories' case. Instead, I use d_instantiate for the
new inode and d_delete for the old one. Is this correct?

Regards,
Martin

diff -u fs/vfat.orig/namei.c fs/vfat/namei.c
--- fs/vfat.orig/namei.c Fri Jul 25 06:54:02 1997
+++ fs/vfat/namei.c Sat Jul 26 16:04:34 1997
@@ -69,13 +69,14 @@

static struct super_operations vfat_sops = {
vfat_read_inode,
- fat_notify_change,
fat_write_inode,
fat_put_inode,
+ NULL, /* delete_inode */
+ fat_notify_change,
vfat_put_super,
- NULL, /* added in 0.96c */
+ NULL, /* write_super */
fat_statfs,
- NULL
+ NULL /* remount */
};

static int parse_options(char *options, struct fat_mount_options *opts)
@@ -910,66 +911,50 @@
return -ENOENT;
}

-int vfat_lookup(struct inode *dir,const char *name,int len,
- struct inode **result)
+int vfat_lookup(struct inode *dir,struct dentry *dentry)
{
- int res, ino;
+ int res;
struct inode *next;
struct slot_info sinfo;
+ struct inode *result;

- PRINTK (("vfat_lookup: name=%s, len=%d\n", name, len));
+ PRINTK (("vfat_lookup: name=%s, len=%d\n",
+ dentry->d_name.name, dentry->d_name.len));

- *result = NULL;
- if (!dir) return -ENOENT;
- if (!S_ISDIR(dir->i_mode)) {
- iput(dir);
- return -ENOENT;
- }
- PRINTK (("vfat_lookup 2\n"));
- if (len == 1 && name[0] == '.') {
- *result = dir;
- return 0;
- }
- if (len == 2 && name[0] == '.' && name[1] == '.') {
- ino = fat_parent_ino(dir,0);
- iput(dir);
- if (ino < 0) return ino;
- if (!(*result = iget(dir->i_sb,ino))) return -EACCES;
+ result = NULL;
+ if ((res = vfat_find(dir,dentry->d_name.name,
+ dentry->d_name.len,1,0,0,&sinfo)) < 0) {
+ d_add(dentry,NULL);
return 0;
}
- PRINTK (("vfat_lookup 3\n"));
- if ((res = vfat_find(dir,name,len,1,0,0,&sinfo)) < 0) {
- iput(dir);
- return res;
- }
PRINTK (("vfat_lookup 4.5\n"));
- if (!(*result = iget(dir->i_sb,sinfo.ino))) {
- iput(dir);
+ if (!(result = iget(dir->i_sb,sinfo.ino)))
return -EACCES;
- }
PRINTK (("vfat_lookup 5\n"));
- if (!(*result)->i_sb ||
- ((*result)->i_sb->s_magic != MSDOS_SUPER_MAGIC)) {
+ if (!result->i_sb ||
+ (result->i_sb->s_magic != MSDOS_SUPER_MAGIC)) {
/* crossed a mount point into a non-msdos fs */
- iput(dir);
+ d_add(dentry,result);
return 0;
}
- if (MSDOS_I(*result)->i_busy) { /* mkdir in progress */
- iput(*result);
- iput(dir);
- return -ENOENT;
+ if (MSDOS_I(result)->i_busy) { /* mkdir in progress */
+ iput(result);
+ d_add(dentry,NULL);
+ return 0;
}
PRINTK (("vfat_lookup 6\n"));
- while (MSDOS_I(*result)->i_old) {
- next = MSDOS_I(*result)->i_old;
- iput(*result);
- if (!(*result = iget(next->i_sb,next->i_ino))) {
+ while (MSDOS_I(result)->i_old) {
+ next = MSDOS_I(result)->i_old;
+ iput(result);
+ if (!(result = iget(next->i_sb,next->i_ino))) {
fat_fs_panic(dir->i_sb,"vfat_lookup: Can't happen");
iput(dir);
return -ENOENT;
}
}
- iput(dir);
+ PRINTK (("vfat_lookup 7\n"));
+ d_add(dentry,result);
+ PRINTK (("vfat_lookup 8\n"));
return 0;
}

@@ -1017,19 +1002,19 @@
return 0;
}

-int vfat_create(struct inode *dir,const char *name,int len,int mode,
- struct inode **result)
+int vfat_create(struct inode *dir,struct dentry* dentry,int mode)
{
int res;
+ struct inode *result;

- if (!dir) return -ENOENT;
-
+ result=NULL;
fat_lock_creation();
- res = vfat_create_entry(dir,name,len,0,result);
+ res = vfat_create_entry(dir,dentry->d_name.name,
+ dentry->d_name.len,0,&result);
if (res < 0) PRINTK(("vfat_create: unable to get new entry\n"));

fat_unlock_creation();
- iput(dir);
+ d_instantiate(dentry,result);
return res;
}

@@ -1271,12 +1256,12 @@
}

/***** Remove a directory */
-int vfat_rmdir(struct inode *dir,const char *name,int len)
+int vfat_rmdir(struct inode *dir,struct dentry* dentry)
{
int res;

- res = vfat_rmdirx(dir, name, len);
- iput(dir);
+ res = vfat_rmdirx(dir, dentry->d_name.name, dentry->d_name.len);
+ d_delete(dentry);
return res;
}

@@ -1311,15 +1296,15 @@
}


-int vfat_mkdir(struct inode *dir,const char *name,int len,int mode)
+int vfat_mkdir(struct inode *dir,struct dentry* dentry,int mode)
{
struct inode *inode;
int res;

fat_lock_creation();
- if ((res = vfat_create_entry(dir,name,len,1,&inode)) < 0) {
+ if ((res = vfat_create_entry(dir,dentry->d_name.name,
+ dentry->d_name.len,1,&inode)) < 0) {
fat_unlock_creation();
- iput(dir);
return res;
}

@@ -1330,28 +1315,27 @@
res = vfat_create_dotdirs(inode, dir);
fat_unlock_creation();
MSDOS_I(inode)->i_busy = 0;
- iput(inode);
- iput(dir);
+ d_instantiate(dentry,inode);
if (res < 0) {
- if (vfat_rmdir(dir,name,len) < 0)
+ if (vfat_rmdir(dir,dentry) < 0)
fat_fs_panic(dir->i_sb,"rmdir in mkdir failed");
}
return res;
}

/***** Unlink, as called for msdosfs */
-int vfat_unlink(struct inode *dir,const char *name,int len)
+int vfat_unlink(struct inode *dir,struct dentry* dentry)
{
int res;

- res = vfat_unlinkx (dir,name,len,1);
- iput(dir);
+ res = vfat_unlinkx (dir,dentry->d_name.name,dentry->d_name.len,1);
+ d_delete(dentry);
return res;
}


-int vfat_rename(struct inode *old_dir,const char *old_name,int old_len,
- struct inode *new_dir,const char *new_name,int new_len)
+int vfat_rename(struct inode *old_dir,struct dentry *old_dentry,
+ struct inode *new_dir,struct dentry *new_dentry)
{
struct super_block *sb = old_dir->i_sb;
struct buffer_head *old_bh,*new_bh,*dotdot_bh;
@@ -1364,13 +1348,16 @@
struct slot_info sinfo;

PRINTK(("vfat_rename 1\n"));
- if (old_dir == new_dir && old_len == new_len &&
- strncmp(old_name, new_name, old_len) == 0)
+ if (old_dir == new_dir &&
+ old_dentry->d_name.len == new_dentry->d_name.len &&
+ strncmp(old_dentry->d_name.name, new_dentry->d_name.name,
+ old_dentry->d_name.len) == 0)
return 0;

old_bh = new_bh = NULL;
old_inode = new_inode = NULL;
- res = vfat_find(old_dir,old_name,old_len,1,0,0,&sinfo);
+ res = vfat_find(old_dir,old_dentry->d_name.name,
+ old_dentry->d_name.len,1,0,0,&sinfo);
PRINTK(("vfat_rename 2\n"));
if (res < 0) goto rename_done;

@@ -1383,8 +1370,7 @@
if (res < 0) goto rename_done;

res = -ENOENT;
- if (!(old_inode = iget(old_dir->i_sb,old_ino)))
- goto rename_done;
+ old_inode = old_dentry->d_inode;
is_dir = S_ISDIR(old_inode->i_mode);
if (is_dir) {
if ((old_dir->i_dev != new_dir->i_dev) ||
@@ -1413,7 +1399,8 @@
iput(walk);
}

- res = vfat_find(new_dir,new_name,new_len,1,0,is_dir,&sinfo);
+ res = vfat_find(new_dir,new_dentry->d_name.name,
+ new_dentry->d_name.len,1,0,is_dir,&sinfo);

PRINTK(("vfat_rename 4\n"));
if (res > -1) {
@@ -1432,12 +1419,14 @@
iput(new_inode);
if (new_is_dir) {
PRINTK(("vfat_rename 7\n"));
- res = vfat_rmdirx(new_dir,new_name,new_len);
+ res = vfat_rmdirx(new_dir,new_dentry->d_name.name,
+ new_dentry->d_name.len);
PRINTK(("vfat_rename 8\n"));
if (res < 0) goto rename_done;
} else {
PRINTK(("vfat_rename 9\n"));
- res = vfat_unlinkx(new_dir,new_name,new_len,1);
+ res = vfat_unlinkx(new_dir,new_dentry->d_name.name,
+ new_dentry->d_name.len,1);
PRINTK(("vfat_rename 10\n"));
if (res < 0) goto rename_done;
}
@@ -1445,7 +1434,8 @@

PRINTK(("vfat_rename 11\n"));
fat_lock_creation(); locked = 1;
- res = vfat_find(new_dir,new_name,new_len,1,1,is_dir,&sinfo);
+ res = vfat_find(new_dir,new_dentry->d_name.name,
+ new_dentry->d_name.len,1,1,is_dir,&sinfo);

PRINTK(("vfat_rename 12\n"));
if (res < 0) goto rename_done;
@@ -1524,6 +1514,8 @@
}

if (res > 0) res = 0;
+ d_instantiate(new_dentry,new_inode);
+ d_delete(old_dentry);

rename_done:
if (locked)
@@ -1532,10 +1524,6 @@
fat_brelse(sb, old_bh);
if (new_bh)
fat_brelse(sb, new_bh);
- if (old_inode)
- iput(old_inode);
- iput(old_dir);
- iput(new_dir);
return res;
}

@@ -1554,6 +1542,7 @@
NULL, /* mknod */
vfat_rename, /* rename */
NULL, /* readlink */
+ NULL, /* followlink */
NULL, /* readpage */
NULL, /* writepage */
fat_bmap, /* bmap */