patch-2.4.19 linux-2.4.19/fs/devfs/base.c

• Lines: 252
• Date: Fri Aug 2 17:39:45 2002
• Orig file: linux-2.4.18/fs/devfs/base.c
• Orig date: Mon Feb 25 11:38:08 2002

diff -urN linux-2.4.18/fs/devfs/base.c linux-2.4.19/fs/devfs/base.c
@@ -608,6 +608,18 @@
 	       Fixed deadlock bug in <devfs_d_revalidate_wait>.
 	       Tag VFS deletable in <devfs_mk_symlink> if handle ignored.
   v1.10
+    20020129   Richard Gooch <rgooch@atnf.csiro.au>
+	       Added KERN_* to remaining messages.
+	       Cleaned up declaration of <stat_read>.
+  v1.11
+    20020219   Richard Gooch <rgooch@atnf.csiro.au>
+	       Changed <devfs_rmdir> to allow later additions if not yet empty.
+  v1.12
+    20020514   Richard Gooch <rgooch@atnf.csiro.au>
+	       Added BKL to <devfs_open> because drivers still need it.
+	       Protected <scan_dir_for_removable> and <get_removable_partition>
+	       from changing directory contents.
+  v1.12a
 */
 #include <linux/types.h>
 #include <linux/errno.h>
@@ -640,7 +652,7 @@
 #include <asm/bitops.h>
 #include <asm/atomic.h>
 
-#define DEVFS_VERSION            "1.10 (20020120)"
+#define DEVFS_VERSION            "1.12a (20020514)"
 
 #define DEVFS_NAME "devfs"
 
@@ -848,8 +860,8 @@
 			 unsigned int cmd, unsigned long arg);
 static int devfsd_close (struct inode *inode, struct file *file);
 #ifdef CONFIG_DEVFS_DEBUG
-static int stat_read (struct file *file, char *buf, size_t len,
-			    loff_t *ppos);
+static ssize_t stat_read (struct file *file, char *buf, size_t len,
+			  loff_t *ppos);
 static struct file_operations stat_fops =
 {
     read:    stat_read,
@@ -2415,6 +2427,9 @@
  *	@de: The device.
  *
  *	Returns 1 if the media was changed, else 0.
+ *
+ *	This function may block, and may indirectly cause the parent directory
+ *	contents to be changed due to partition re-reading.
  */
 
 static int check_disc_changed (struct devfs_entry *de)
@@ -2431,10 +2446,10 @@
     if (bdops->check_media_change == NULL) goto out;
     if ( !bdops->check_media_change (dev) ) goto out;
     retval = 1;
-    printk ( KERN_DEBUG "VFS: Disk change detected on device %s\n",
+    printk (KERN_DEBUG "VFS: Disk change detected on device %s\n",
 	     kdevname (dev) );
-    if (invalidate_device(dev, 0))
-	printk("VFS: busy inodes on changed media..\n");
+    if ( invalidate_device (dev, 0) )
+	printk (KERN_WARNING "VFS: busy inodes on changed media..\n");
     /*  Ugly hack to disable messages about unable to read partition table  */
     tmp = warn_no_part;
     warn_no_part = 0;
@@ -2449,19 +2464,29 @@
 /**
  *	scan_dir_for_removable - Scan a directory for removable media devices and check media.
  *	@dir: The directory.
+ *
+ *	This function may block, and may indirectly cause the directory
+ *	contents to be changed due to partition re-reading. The directory will
+ *	be locked for reading.
  */
 
 static void scan_dir_for_removable (struct devfs_entry *dir)
 {
     struct devfs_entry *de;
 
-    if (dir->u.dir.num_removable < 1) return;
-    for (de = dir->u.dir.first; de != NULL; de = de->next)
+    read_lock (&dir->u.dir.lock);
+    if (dir->u.dir.num_removable < 1) de = NULL;
+    else
     {
-	if ( !S_ISBLK (de->mode) ) continue;
-	if (!de->u.fcb.removable) continue;
-	check_disc_changed (de);
+	for (de = dir->u.dir.first; de != NULL; de = de->next)
+	{
+	    if (S_ISBLK (de->mode) && de->u.fcb.removable) break;
+	}
+	devfs_get (de);
     }
+    read_unlock (&dir->u.dir.lock);
+    if (de) check_disc_changed (de);
+    devfs_put (de);
 }   /*  End Function scan_dir_for_removable  */
 
 /**
@@ -2471,25 +2496,37 @@
  *	@namelen: The number of characters in <<name>>.
  *
  *	Returns 1 if the media was changed, else 0.
+ *
+ *	This function may block, and may indirectly cause the directory
+ *	contents to be changed due to partition re-reading. The directory must
+ *	be locked for reading upon entry, and will be unlocked upon exit.
  */
 
 static int get_removable_partition (struct devfs_entry *dir, const char *name,
 				    unsigned int namelen)
 {
+    int retval;
     struct devfs_entry *de;
 
+    if (dir->u.dir.num_removable < 1)
+    {
+	read_unlock (&dir->u.dir.lock);
+	return 0;
+    }
     for (de = dir->u.dir.first; de != NULL; de = de->next)
     {
-	if ( !S_ISBLK (de->mode) ) continue;
-	if (!de->u.fcb.removable) continue;
-	if (strcmp (de->name, "disc") == 0) return check_disc_changed (de);
+	if (!S_ISBLK (de->mode) || !de->u.fcb.removable) continue;
+	if (strcmp (de->name, "disc") == 0) break;
 	/*  Support for names where the partition is appended to the disc name
 	 */
 	if (de->namelen >= namelen) continue;
-	if (strncmp (de->name, name, de->namelen) != 0) continue;
-	return check_disc_changed (de);
+	if (strncmp (de->name, name, de->namelen) == 0) break;
     }
-    return 0;
+    devfs_get (de);
+    read_unlock (&dir->u.dir.lock);
+    retval = de ? check_disc_changed (de) : 0;
+    devfs_put (de);
+    return retval;
 }   /*  End Function get_removable_partition  */
 
 
@@ -2738,15 +2775,22 @@
     {
 	file->f_op = &def_blk_fops;
 	if (df->ops) inode->i_bdev->bd_op = df->ops;
+	err = def_blk_fops.open (inode, file);
     }
-    else file->f_op = fops_get ( (struct file_operations *) df->ops );
-    if (file->f_op)
-	err = file->f_op->open ? (*file->f_op->open) (inode, file) : 0;
     else
     {
-	/*  Fallback to legacy scheme  */
-	if ( S_ISCHR (inode->i_mode) ) err = chrdev_open (inode, file);
-	else err = -ENODEV;
+	file->f_op = fops_get ( (struct file_operations *) df->ops );
+	if (file->f_op)
+	{
+	    lock_kernel ();
+	    err = file->f_op->open ? (*file->f_op->open) (inode, file) : 0;
+	    unlock_kernel ();
+	}
+	else
+	{   /*  Fallback to legacy scheme  */
+	    if ( S_ISCHR (inode->i_mode) ) err = chrdev_open (inode, file);
+	    else err = -ENODEV;
+	}
     }
     if (err < 0) return err;
     /*  Open was successful  */
@@ -2946,15 +2990,17 @@
     if (parent == NULL) return ERR_PTR (-ENOENT);
     read_lock (&parent->u.dir.lock);
     de = _devfs_search_dir (parent, dentry->d_name.name, dentry->d_name.len);
-    read_unlock (&parent->u.dir.lock);
-    if ( (de == NULL) && (parent->u.dir.num_removable > 0) &&
-	 get_removable_partition (parent, dentry->d_name.name,
-				  dentry->d_name.len) )
-    {
-	read_lock (&parent->u.dir.lock);
-	de = _devfs_search_dir (parent, dentry->d_name.name,
-				dentry->d_name.len);
-	read_unlock (&parent->u.dir.lock);
+    if (de) read_unlock (&parent->u.dir.lock);
+    else
+    {   /*  Try re-reading the partition (media may have changed)  */
+	if ( get_removable_partition (parent, dentry->d_name.name,
+				      dentry->d_name.len) )  /*  Unlocks  */
+	{   /*  Media did change  */
+	    read_lock (&parent->u.dir.lock);
+	    de = _devfs_search_dir (parent, dentry->d_name.name,
+				    dentry->d_name.len);
+	    read_unlock (&parent->u.dir.lock);
+	}
     }
     lookup_info.de = de;
     init_waitqueue_head (&lookup_info.wait_queue);
@@ -3112,10 +3158,10 @@
     if (de == NULL) return -ENOENT;
     if ( !S_ISDIR (de->mode) ) return -ENOTDIR;
     if (!de->vfs_deletable) return -EPERM;
-    /*  First ensure the directory is empty and will stay thay way  */
+    /*  First ensure the directory is empty and will stay that way  */
     write_lock (&de->u.dir.lock);
-    de->u.dir.no_more_additions = TRUE;
     if (de->u.dir.first) err = -ENOTEMPTY;
+    else de->u.dir.no_more_additions = TRUE;
     write_unlock (&de->u.dir.lock);
     if (err) return err;
     /*  Now unhook the directory from it's parent  */
@@ -3237,7 +3283,7 @@
     return sb;
 
 out_no_root:
-    printk ("devfs_read_super: get root inode failed\n");
+    PRINTK ("(): get root inode failed\n");
     if (root_inode) iput (root_inode);
     return NULL;
 }   /*  End Function devfs_read_super  */
@@ -3464,7 +3510,7 @@
 {
     int err;
 
-    printk ("%s: v%s Richard Gooch (rgooch@atnf.csiro.au)\n",
+    printk (KERN_INFO "%s: v%s Richard Gooch (rgooch@atnf.csiro.au)\n",
 	    DEVFS_NAME, DEVFS_VERSION);
     devfsd_buf_cache = kmem_cache_create ("devfsd_event",
 					  sizeof (struct devfsd_buf_entry),
@@ -3472,9 +3518,9 @@
     if (!devfsd_buf_cache) OOPS ("(): unable to allocate event slab\n");
 #ifdef CONFIG_DEVFS_DEBUG
     devfs_debug = devfs_debug_init;
-    printk ("%s: devfs_debug: 0x%0x\n", DEVFS_NAME, devfs_debug);
+    printk (KERN_INFO "%s: devfs_debug: 0x%0x\n", DEVFS_NAME, devfs_debug);
 #endif
-    printk ("%s: boot_options: 0x%0x\n", DEVFS_NAME, boot_options);
+    printk (KERN_INFO "%s: boot_options: 0x%0x\n", DEVFS_NAME, boot_options);
     err = register_filesystem (&devfs_fs_type);
     if (!err)
     {
@@ -3491,8 +3537,8 @@
 
     if ( !(boot_options & OPTION_MOUNT) ) return;
     err = do_mount ("none", "/dev", "devfs", 0, "");
-    if (err == 0) printk ("Mounted devfs on /dev\n");
-    else printk ("Warning: unable to mount devfs, err: %d\n", err);
+    if (err == 0) printk (KERN_INFO "Mounted devfs on /dev\n");
+    else PRINTK ("(): unable to mount devfs, err: %d\n", err);
 }   /*  End Function mount_devfs_fs  */
 
 module_init(init_devfs_fs)