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Subject[PATCH] Next cut of new devfs core
  Hi, all. Another cut of the new devfs core. This should get the
low-level append/unregister/unlink/rmdir working properly.

Patch against 2.4.14.

Regards,

Richard....
Permanent: rgooch@atnf.csiro.au
Current: rgooch@ras.ucalgary.ca

diff -urN linux-2.4.14/fs/devfs/base.c linux/fs/devfs/base.c
--- linux-2.4.14/fs/devfs/base.c Sat Nov 3 11:06:38 2001
+++ linux/fs/devfs/base.c Wed Nov 7 12:11:25 2001
@@ -545,21 +545,15 @@
20010919 Richard Gooch <rgooch@atnf.csiro.au>
Set inode->i_mapping->a_ops for block nodes in <get_vfs_inode>.
v0.116
- 20010927 Richard Gooch <rgooch@atnf.csiro.au>
- Went back to global rwsem for symlinks (refcount scheme no good)
- v0.117
20011008 Richard Gooch <rgooch@atnf.csiro.au>
Fixed overrun in <devfs_link> by removing function (not needed).
- v0.118
20011009 Richard Gooch <rgooch@atnf.csiro.au>
Fixed buffer underrun in <try_modload>.
- Moved down_read() from <search_for_entry_in_dir> to <find_entry>
- v0.119
20011029 Richard Gooch <rgooch@atnf.csiro.au>
Fixed race in <devfsd_ioctl> when setting event mask.
- 20011103 Richard Gooch <rgooch@atnf.csiro.au>
- Avoid deadlock in <devfs_follow_link> by using temporary buffer.
- v0.120
+ 20011107 Richard Gooch <rgooch@atnf.csiro.au>
+ Pre-alpha cut of new locking code.
+ v1.0-pre3
*/
#include <linux/types.h>
#include <linux/errno.h>
@@ -592,7 +586,7 @@
#include <asm/bitops.h>
#include <asm/atomic.h>

-#define DEVFS_VERSION "0.120 (20011103)"
+#define DEVFS_VERSION "1.0-pre3 (20011107)"

#define DEVFS_NAME "devfs"

@@ -605,14 +599,14 @@
# define FALSE 0
#endif

-#define IS_HIDDEN(de) (( ((de)->hide && !is_devfsd_or_child(fs_info)) || !(de)->registered))
+#define IS_HIDDEN(de) ( (de)->hide && !is_devfsd_or_child(fs_info) )

#define DEBUG_NONE 0x00000
#define DEBUG_MODULE_LOAD 0x00001
#define DEBUG_REGISTER 0x00002
#define DEBUG_UNREGISTER 0x00004
#define DEBUG_SET_FLAGS 0x00008
-#define DEBUG_S_PUT 0x00010
+#define DEBUG_S_READ 0x00010
#define DEBUG_I_LOOKUP 0x00020
#define DEBUG_I_CREATE 0x00040
#define DEBUG_I_GET 0x00080
@@ -638,9 +632,11 @@

struct directory_type
{
+ rwlock_t lock; /* Lock for searching(R)/updating(W) */
struct devfs_entry *first;
struct devfs_entry *last;
- unsigned int num_removable;
+ unsigned short num_removable;
+ unsigned char no_more_additions:1;
};

struct file_type
@@ -684,12 +680,12 @@
gid_t gid;
};

-struct devfs_inode /* This structure is for "persistent" inode storage */
+struct devfs_inode /* This structure is for "persistent" inode storage */
{
time_t atime;
time_t mtime;
time_t ctime;
- unsigned int ino; /* Inode number as seen in the VFS */
+ unsigned int ino; /* Inode number as seen in the VFS */
struct dentry *dentry;
umode_t mode;
uid_t uid;
@@ -699,6 +695,7 @@
struct devfs_entry
{
void *info;
+ atomic_t refcount; /* When this drops to zero, it's unused */
union
{
struct directory_type dir;
@@ -713,12 +710,11 @@
struct devfs_entry *slave; /* Another entry to unregister */
struct devfs_inode inode;
umode_t mode;
- unsigned short namelen; /* I think 64k+ filenames are a way off... */
- unsigned char registered:1;
+ unsigned short namelen; /* I think 64k+ filenames are a way off... */
unsigned char hide:1;
- unsigned char no_persistence:1;
- char name[1]; /* This is just a dummy: the allocated array is
- bigger. This is NULL-terminated */
+ unsigned char vfs_created:1; /* Whether created by driver or VFS */
+ char name[1]; /* This is just a dummy: the allocated array
+ is bigger. This is NULL-terminated */
};

/* The root of the device tree */
@@ -733,7 +729,7 @@
gid_t gid;
};

-struct fs_info /* This structure is for the mounted devfs */
+struct fs_info /* This structure is for the mounted devfs */
{
struct super_block *sb;
volatile struct devfsd_buf_entry *devfsd_buffer;
@@ -763,14 +759,10 @@
static unsigned int boot_options = OPTION_NONE;
#endif

-static DECLARE_RWSEM (symlink_rwsem);
-
/* Forward function declarations */
-static struct devfs_entry *search_for_entry (struct devfs_entry *dir,
- const char *name,
- unsigned int namelen, int mkdir,
- int mkfile, int *is_new,
- int traverse_symlink);
+static devfs_handle_t _devfs_walk_path (struct devfs_entry *dir,
+ const char *name, int namelen,
+ int traverse_symlink);
static ssize_t devfsd_read (struct file *file, char *buf, size_t len,
loff_t *ppos);
static int devfsd_ioctl (struct inode *inode, struct file *file,
@@ -791,22 +783,52 @@


/**
- * search_for_entry_in_dir - Search for a devfs entry inside another devfs entry.
+ * devfs_get - Get a reference to a devfs entry.
+ * @de: The devfs entry.
+ */
+
+static struct devfs_entry *devfs_get (struct devfs_entry *de)
+{
+ if (de) atomic_inc (&de->refcount);
+ return de;
+} /* End Function devfs_get */
+
+/**
+ * devfs_put - Put (release) a reference to a devfs entry.
+ * @de: The devfs entry.
+ */
+
+static void devfs_put (struct devfs_entry *de)
+{
+ if (!de) return;
+ if ( !atomic_dec_and_test (&de->refcount) ) return;
+ if ( S_ISLNK (de->mode) ) kfree (de->u.symlink.linkname);
+ if ( ( S_ISCHR (de->mode) || S_ISBLK (de->mode) ) && de->u.fcb.autogen )
+ {
+ devfs_dealloc_devnum ( S_ISCHR (de->mode) ? DEVFS_SPECIAL_CHR :
+ DEVFS_SPECIAL_BLK,
+ MKDEV (de->u.fcb.u.device.major,
+ de->u.fcb.u.device.minor) );
+ }
+ kfree (de);
+} /* End Function devfs_put */
+
+/**
+ * _devfs_search_dir - Search for a devfs entry inside another devfs entry.
* @parent: The parent devfs entry.
* @name: The name of the entry.
* @namelen: The number of characters in @name.
- * @traverse_symlink: If %TRUE then the entry is traversed if it is a symlink.
*
* Search for a devfs entry inside another devfs entry and returns a pointer
- * to the entry on success, else %NULL.
+ * to the entry on success, else %NULL. The parent must be locked already.
+ * An implicit devfs_get() is performed on the returned entry.
*/

-static struct devfs_entry *search_for_entry_in_dir (struct devfs_entry *parent,
- const char *name,
- unsigned int namelen,
- int traverse_symlink)
+static struct devfs_entry *_devfs_search_dir (struct devfs_entry *parent,
+ const char *name,
+ unsigned int namelen)
{
- struct devfs_entry *curr, *retval;
+ struct devfs_entry *curr;

if ( !S_ISDIR (parent->mode) )
{
@@ -819,18 +841,21 @@
if (memcmp (curr->name, name, namelen) == 0) break;
/* Not found: try the next one */
}
- if (curr == NULL) return NULL;
- if (!S_ISLNK (curr->mode) || !traverse_symlink) return curr;
- /* Need to follow the link: this is a stack chomper */
- retval = curr->registered ?
- search_for_entry (parent, curr->u.symlink.linkname,
- curr->u.symlink.length, FALSE, FALSE, NULL,
- TRUE) : NULL;
- return retval;
-} /* End Function search_for_entry_in_dir */
+ return devfs_get (curr);
+} /* End Function _devfs_search_dir */

-static struct devfs_entry *create_entry (struct devfs_entry *parent,
- const char *name,unsigned int namelen)
+
+/**
+ * _devfs_alloc_entry - Allocate a devfs entry.
+ * @name: The name of the entry.
+ * @namelen: The number of characters in @name.
+ *
+ * Allocate a devfs entry and returns a pointer to the entry on success, else
+ * %NULL.
+ */
+
+static struct devfs_entry *_devfs_alloc_entry (const char *name,
+ unsigned int namelen)
{
struct devfs_entry *new;
static unsigned long inode_counter = FIRST_INODE;
@@ -842,20 +867,79 @@
/* Magic: this will set the ctime to zero, thus subsequent lookups will
trigger the call to <update_devfs_inode_from_entry> */
memset (new, 0, sizeof *new + namelen);
+ atomic_set (&new->refcount, 1);
spin_lock (&counter_lock);
new->inode.ino = inode_counter++;
spin_unlock (&counter_lock);
- new->parent = parent;
if (name) memcpy (new->name, name, namelen);
new->namelen = namelen;
- if (parent == NULL) return new;
- new->prev = parent->u.dir.last;
- /* Insert into the parent directory's list of children */
- if (parent->u.dir.first == NULL) parent->u.dir.first = new;
- else parent->u.dir.last->next = new;
- parent->u.dir.last = new;
return new;
-} /* End Function create_entry */
+} /* End Function _devfs_alloc_entry */
+
+
+/**
+ * _devfs_alloc_dir - Allocate and initialise a devfs directory.
+ * @name: The name of the entry.
+ * @namelen: The number of characters in @name.
+ *
+ * Allocate a devfs directory and returns a pointer to the entry on success, else
+ * %NULL.
+ */
+
+static devfs_handle_t _devfs_alloc_dir (const char *name, unsigned int namelen)
+{
+ struct devfs_entry *de;
+
+ if ( ( de = _devfs_alloc_entry (name, namelen) ) == NULL ) return NULL;
+ de->mode = S_IFDIR | S_IRUGO | S_IXUGO;
+ rwlock_init (&de->u.dir.lock);
+ return de;
+} /* End Function _devfs_alloc_dir */
+
+
+/**
+ * append_entry - Append a devfs entry to a directory's list of children.
+ * @dir: The directory to add to.
+ * @de: The devfs entry to append.
+ *
+ * Append a devfs entry to a directory's list of children, checking first to
+ * see if an entry of the same name exists. The directory will be locked.
+ * The value 0 is returned on success, else a negative error code.
+ */
+
+static int append_entry (struct devfs_entry *dir, struct devfs_entry *de)
+{
+ int retval;
+ struct devfs_entry *old;
+
+ if (!de || !dir) return 0;
+ if ( !S_ISDIR (dir->mode) )
+ {
+ printk ("%s: append_entry(): dir: \"%s\" is not a directory\n",
+ DEVFS_NAME, dir->name);
+ return -ENOTDIR;
+ }
+ write_lock (&dir->u.dir.lock);
+ if (dir->u.dir.no_more_additions) retval = -ENOENT;
+ else
+ {
+ old = _devfs_search_dir (dir, de->name, de->namelen);
+ devfs_put (old);
+ if (old == NULL)
+ {
+ de->parent = dir;
+ de->prev = dir->u.dir.last;
+ /* Append to the directory's list of children */
+ if (dir->u.dir.first == NULL) dir->u.dir.first = de;
+ else dir->u.dir.last->next = de;
+ dir->u.dir.last = de;
+ retval = 0;
+ }
+ else retval = -EEXIST;
+ }
+ write_unlock (&dir->u.dir.lock);
+ return retval;
+} /* End Function append_entry */

static void update_devfs_inode_from_entry (struct devfs_entry *de)
{
@@ -889,26 +973,33 @@
} /* End Function update_devfs_inode_from_entry */

/**
- * get_root_entry - Get the root devfs entry.
+ * _devfs_get_root_entry - Get the root devfs entry.
*
* Returns the root devfs entry on success, else %NULL.
*/

-static struct devfs_entry *get_root_entry (void)
+static struct devfs_entry *_devfs_get_root_entry (void)
{
kdev_t devnum;
struct devfs_entry *new;
+ static spinlock_t root_lock = SPIN_LOCK_UNLOCKED;

/* Always ensure the root is created */
- if (root_entry != NULL) return root_entry;
- if ( ( root_entry = create_entry (NULL, NULL, 0) ) == NULL ) return NULL;
- root_entry->mode = S_IFDIR;
+ if (root_entry) return root_entry;
+ if ( ( new = _devfs_alloc_dir (NULL, 0) ) == NULL ) return NULL;
/* Force an inode update, because lookup() is never done for the root */
- update_devfs_inode_from_entry (root_entry);
- root_entry->registered = TRUE;
+ update_devfs_inode_from_entry (new);
+ spin_lock (&root_lock);
+ if (root_entry)
+ {
+ spin_unlock (&root_lock);
+ devfs_put (new);
+ return (root_entry);
+ }
+ root_entry = new;
+ spin_unlock (&root_lock);
/* And create the entry for ".devfsd" */
- if ( ( new = create_entry (root_entry, ".devfsd", 0) ) == NULL )
- return NULL;
+ if ( ( new = _devfs_alloc_entry (".devfsd", 0) ) == NULL ) return NULL;
devnum = devfs_alloc_devnum (DEVFS_SPECIAL_CHR);
new->u.fcb.u.device.major = MAJOR (devnum);
new->u.fcb.u.device.minor = MINOR (devnum);
@@ -916,91 +1007,140 @@
new->u.fcb.default_uid = 0;
new->u.fcb.default_gid = 0;
new->u.fcb.ops = &devfsd_fops;
- new->registered = TRUE;
+ append_entry (root_entry, new);
return root_entry;
-} /* End Function get_root_entry */
+} /* End Function _devfs_get_root_entry */


-/**
- * search_for_entry - Search for an entry in the devfs tree.
- * @dir: The parent directory to search from. If this is %NULL the root is used
- * @name: The name of the entry.
- * @namelen: The number of characters in @name.
- * @mkdir: If %TRUE intermediate directories are created as needed.
- * @mkfile: If %TRUE the file entry is created if it doesn't exist.
- * @is_new: If the returned entry was newly made, %TRUE is written here. If
- * this is %NULL nothing is written here.
- * @traverse_symlink: If %TRUE then symbolic links are traversed.
- *
- * If the entry is created, then it will be in the unregistered state.
- * Returns a pointer to the entry on success, else %NULL.
- */
-
-static struct devfs_entry *search_for_entry (struct devfs_entry *dir,
- const char *name,
- unsigned int namelen, int mkdir,
- int mkfile, int *is_new,
- int traverse_symlink)
+static struct devfs_entry *_devfs_descend (struct devfs_entry *dir,
+ const char *name, int namelen,
+ int *next_pos)
{
- int len;
- const char *subname, *stop, *ptr;
+ const char *stop, *ptr;
struct devfs_entry *entry;

- if (is_new) *is_new = FALSE;
- if (dir == NULL) dir = get_root_entry ();
- if (dir == NULL) return NULL;
- /* Extract one filename component */
- subname = name;
+ if ( (namelen >= 3) && (strncmp (name, "../", 3) == 0) )
+ { /* Special-case going to parent directory */
+ *next_pos = 3;
+ return devfs_get (dir->parent);
+ }
stop = name + namelen;
- while (subname < stop)
+ /* Search for a possible '/' */
+ for (ptr = name; (ptr < stop) && (*ptr != '/'); ++ptr);
+ *next_pos = ptr - name;
+ read_lock (&dir->u.dir.lock);
+ entry = _devfs_search_dir (dir, name, *next_pos);
+ read_unlock (&dir->u.dir.lock);
+ return entry;
+} /* End Function _devfs_descend */
+
+
+static devfs_handle_t _devfs_make_parent_for_leaf (struct devfs_entry *dir,
+ const char *name,
+ int namelen, int *leaf_pos)
+{
+ int next_pos = 0;
+ struct devfs_entry *de;
+
+ if (dir == NULL) dir = _devfs_get_root_entry ();
+ if (dir == NULL) return NULL;
+ devfs_get (dir);
+ /* Search for possible trailing component and ignore it */
+ for (--namelen; (namelen > 0) && (name[namelen] != '/'); --namelen);
+ *leaf_pos = (name[namelen] == '/') ? (namelen + 1) : 0;
+ for (; namelen > 0; name += next_pos, namelen -= next_pos)
{
- /* Search for a possible '/' */
- for (ptr = subname; (ptr < stop) && (*ptr != '/'); ++ptr);
- if (ptr >= stop)
- {
- /* Look for trailing component */
- len = stop - subname;
- entry = search_for_entry_in_dir (dir, subname, len,
- traverse_symlink);
- if (entry != NULL) return entry;
- if (!mkfile) return NULL;
- entry = create_entry (dir, subname, len);
- if (entry && is_new) *is_new = TRUE;
- return entry;
- }
- /* Found '/': search for directory */
- if (strncmp (subname, "../", 3) == 0)
+ if ( ( de = _devfs_descend (dir, name, namelen, &next_pos) ) == NULL )
{
- /* Going up */
- dir = dir->parent;
- if (dir == NULL) return NULL; /* Cannot escape from devfs */
- subname += 3;
- continue;
+ if ( ( de = _devfs_alloc_dir (name, next_pos) ) == NULL )
+ {
+ devfs_put (dir);
+ return NULL;
+ }
+ if ( append_entry (dir, de) )
+ {
+ devfs_put (dir);
+ devfs_put (de);
+ return NULL;
+ }
+ devfs_get (de);
}
- len = ptr - subname;
- entry = search_for_entry_in_dir (dir, subname, len, traverse_symlink);
- if (!entry && !mkdir) return NULL;
- if (entry == NULL)
+ if (de == dir->parent)
{
- /* Make it */
- if ( ( entry = create_entry (dir, subname, len) ) == NULL )
- return NULL;
- entry->mode = S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR;
- if (is_new) *is_new = TRUE;
+ devfs_put (dir);
+ devfs_put (de);
+ return NULL;
}
- if ( !S_ISDIR (entry->mode) )
+ devfs_put (dir);
+ dir = de;
+ if (name[next_pos] == '/') ++next_pos;
+ }
+ return dir;
+} /* End Function _devfs_make_parent_for_leaf */
+
+
+static devfs_handle_t _devfs_prepare_leaf (devfs_handle_t *dir,
+ const char *name)
+{
+ int namelen, leaf_pos;
+ struct devfs_entry *de;
+
+ namelen = strlen (name);
+ if ( ( *dir = _devfs_make_parent_for_leaf (*dir, name, namelen,
+ &leaf_pos) ) == NULL )
+ {
+ printk ("%s: prepare_leaf(%s): could not create parent path\n",
+ DEVFS_NAME, name);
+ return NULL;
+ }
+ if ( ( de = _devfs_alloc_entry (name + leaf_pos, namelen - leaf_pos) )
+ == NULL )
+ {
+ printk ("%s: prepare_leaf(%s): could not allocate entry\n",
+ DEVFS_NAME, name);
+ devfs_put (*dir);
+ return NULL;
+ }
+ return de;
+} /* End Function _devfs_prepare_leaf */
+
+
+static devfs_handle_t _devfs_walk_path (struct devfs_entry *dir,
+ const char *name, int namelen,
+ int traverse_symlink)
+{
+ int next_pos = 0;
+
+ if (dir == NULL) dir = _devfs_get_root_entry ();
+ if (dir == NULL) return NULL;
+ devfs_get (dir);
+ for (; namelen > 0; name += next_pos, namelen -= next_pos)
+ {
+ struct devfs_entry *de, *link;
+
+ if ( ( de = _devfs_descend (dir, name, namelen, &next_pos) ) == NULL )
{
- printk ("%s: existing non-directory entry\n", DEVFS_NAME);
+ devfs_put (dir);
return NULL;
}
- /* Ensure an unregistered entry is re-registered and visible */
- entry->hide = FALSE;
- entry->registered = TRUE;
- subname = ptr + 1;
- dir = entry;
+ if (S_ISLNK (de->mode) && traverse_symlink)
+ { /* Need to follow the link: this is a stack chomper */
+ link = _devfs_walk_path (dir, de->u.symlink.linkname,
+ de->u.symlink.length, TRUE);
+ devfs_put (de);
+ if (!link)
+ {
+ devfs_put (dir);
+ return NULL;
+ }
+ de = link;
+ }
+ devfs_put (dir);
+ dir = de;
+ if (name[next_pos] == '/') ++next_pos;
}
- return NULL;
-} /* End Function search_for_entry */
+ return dir;
+} /* End Function _devfs_walk_path */


/**
@@ -1063,7 +1203,6 @@
* %DEVFS_SPECIAL_CHR or %DEVFS_SPECIAL_BLK.
* @traverse_symlink: If %TRUE then symbolic links are traversed.
*
- * FIXME: What the hell is @handle? - ch
* Returns the devfs_entry pointer on success, else %NULL.
*/

@@ -1095,10 +1234,7 @@
++name;
--namelen;
}
- if (traverse_symlink) down_read (&symlink_rwsem);
- entry = search_for_entry (dir, name, namelen, FALSE, FALSE, NULL,
- traverse_symlink);
- if (traverse_symlink) up_read (&symlink_rwsem);
+ entry = _devfs_walk_path (dir, name, namelen, traverse_symlink);
if (entry != NULL) return entry;
}
/* Have to search by major and minor: slow */
@@ -1114,7 +1250,7 @@
if (inode == NULL) return NULL;
de = inode->u.generic_ip;
if (!de) printk (__FUNCTION__ "(): NULL de for inode %ld\n", inode->i_ino);
- if (do_check && de && !de->registered) de = NULL;
+ /*FIXME: what to do with do_check? */
return de;
} /* End Function get_devfs_entry_from_vfs_inode */

@@ -1201,8 +1337,9 @@


/**
- * devfsd_notify_one - Notify a single devfsd daemon of a change.
- * @data: Data to be passed.
+ * devfsd_notify_one - Notify the devfsd daemon of a change.
+ * @data: Data to be passed. This must remain in scope until devfsd has
+ * processed the event.
* @type: The type of change.
* @mode: The mode of the entry.
* @uid: The user ID.
@@ -1246,17 +1383,43 @@


/**
- * devfsd_notify - Notify all devfsd daemons of a change.
+ * devfsd_notify_de - Notify the devfsd daemon of a change.
+ * @de: The devfs entry that has changed. This and all parent entries will
+ * have their reference counts incremented if the event was queued.
+ * @type: The type of change.
+ * @mode: The mode of the entry.
+ * @uid: The user ID.
+ * @gid: The group ID.
+ * @fs_info: The filesystem info.
+ *
+ * Returns %TRUE if an event was queued and devfsd woken up, else %FALSE.
+ */
+
+static int devfsd_notify_de (struct devfs_entry *de,
+ unsigned int type, umode_t mode,
+ uid_t uid, gid_t gid, struct fs_info *fs_info)
+{
+ if ( devfsd_notify_one (de, type, mode, uid, gid, fs_info) )
+ {
+ for (; de != NULL; de = de->parent) devfs_get (de);
+ return (TRUE);
+ }
+ return (FALSE);
+} /* End Function devfsd_notify_de */
+
+
+/**
+ * devfsd_notify - Notify the devfsd daemon of a change.
* @de: The devfs entry that has changed.
* @type: The type of change event.
- * @wait: If TRUE, the functions waits for all daemons to finish processing
+ * @wait: If TRUE, the function waits for the daemon to finish processing
* the event.
*/

static void devfsd_notify (struct devfs_entry *de, unsigned int type, int wait)
{
- if (devfsd_notify_one (de, type, de->mode, current->euid,
- current->egid, &fs_info) && wait)
+ if (devfsd_notify_de (de, type, de->mode, current->euid,
+ current->egid, &fs_info) && wait)
wait_for_devfsd_finished (&fs_info);
} /* End Function devfsd_notify */

@@ -1287,7 +1450,6 @@
umode_t mode, void *ops, void *info)
{
char devtype = S_ISCHR (mode) ? DEVFS_SPECIAL_CHR : DEVFS_SPECIAL_BLK;
- int is_new;
kdev_t devnum = NODEV;
struct devfs_entry *de;

@@ -1332,39 +1494,13 @@
major = MAJOR (devnum);
minor = MINOR (devnum);
}
- de = search_for_entry (dir, name, strlen (name), TRUE, TRUE, &is_new,
- FALSE);
- if (de == NULL)
+ if ( ( de = _devfs_prepare_leaf (&dir, name) ) == NULL )
{
- printk ("%s: devfs_register(): could not create entry: \"%s\"\n",
+ printk ("%s: devfs_register(%s): could not prepare leaf\n",
DEVFS_NAME, name);
if (devnum != NODEV) devfs_dealloc_devnum (devtype, devnum);
return NULL;
}
-#ifdef CONFIG_DEVFS_DEBUG
- if (devfs_debug & DEBUG_REGISTER)
- printk ("%s: devfs_register(%s): de: %p %s\n",
- DEVFS_NAME, name, de, is_new ? "new" : "existing");
-#endif
- if (!is_new)
- {
- /* Existing entry */
- if ( !S_ISCHR (de->mode) && !S_ISBLK (de->mode) &&
- !S_ISREG (de->mode) )
- {
- printk ("%s: devfs_register(): existing non-device/file entry: \"%s\"\n",
- DEVFS_NAME, name);
- if (devnum != NODEV) devfs_dealloc_devnum (devtype, devnum);
- return NULL;
- }
- if (de->registered)
- {
- printk("%s: devfs_register(): device already registered: \"%s\"\n",
- DEVFS_NAME, name);
- if (devnum != NODEV) devfs_dealloc_devnum (devtype, devnum);
- return NULL;
- }
- }
de->u.fcb.autogen = FALSE;
if ( S_ISCHR (mode) || S_ISBLK (mode) )
{
@@ -1375,8 +1511,11 @@
else if ( S_ISREG (mode) ) de->u.fcb.u.file.size = 0;
else
{
- printk ("%s: devfs_register(): illegal mode: %x\n",
- DEVFS_NAME, mode);
+ printk ("%s: devfs_register(%s): illegal mode: %x\n",
+ DEVFS_NAME, name, mode);
+ devfs_put (de);
+ devfs_put (dir);
+ if (devnum != NODEV) devfs_dealloc_devnum (devtype, devnum);
return (NULL);
}
de->info = info;
@@ -1401,77 +1540,86 @@
}
de->u.fcb.open = FALSE;
de->hide = (flags & DEVFS_FL_HIDE) ? TRUE : FALSE;
- de->no_persistence = (flags & DEVFS_FL_NO_PERSISTENCE) ? TRUE : FALSE;
- de->registered = TRUE;
+ if ( append_entry (dir, de) )
+ {
+ printk ("%s: devfs_register(%s): could not append to parent\n",
+ DEVFS_NAME, name);
+ devfs_put (de);
+ devfs_put (dir);
+ if (devnum != NODEV) devfs_dealloc_devnum (devtype, devnum);
+ return NULL;
+ }
+#ifdef CONFIG_DEVFS_DEBUG
+ if (devfs_debug & DEBUG_REGISTER)
+ printk ("%s: devfs_register(%s): de: %p\n", DEVFS_NAME, name, de);
+#endif
devfsd_notify (de, DEVFSD_NOTIFY_REGISTERED, flags & DEVFS_FL_WAIT);
+ devfs_put (dir);
return de;
} /* End Function devfs_register */


/**
- * unregister - Unregister a device entry.
+ * _devfs_unhook - Unhook a device entry from its parents list
+ * @de: The entry to unhook.
+ *
+ * Returns %TRUE if the entry was unhooked, else %FALSE if it was
+ * previously unhooked.
+ * The caller must have a write lock on the parent directory.
+ */
+
+static int _devfs_unhook (struct devfs_entry *de)
+{
+ struct devfs_entry *parent;
+
+ if ( !de || (de->prev == de) ) return FALSE;
+ parent = de->parent;
+ if (de->prev == NULL) parent->u.dir.first = de->next;
+ else de->prev->next = de->next;
+ if (de->next == NULL) parent->u.dir.last = de->prev;
+ else de->next->prev = de->prev;
+ de->prev = de; /* Indicate we're unhooked */
+ de->next = NULL; /* Force early termination for <devfs_readdir> */
+ return TRUE;
+} /* End Function _devfs_unhook */
+
+
+/**
+ * unregister - Unregister a device entry from it's parent.
+ * @dir: The parent directory.
* @de: The entry to unregister.
+ *
+ * The caller must have a write lock on the parent directory, which is
+ * unlocked by this function.
*/

-static void unregister (struct devfs_entry *de)
+static void unregister (struct devfs_entry *dir, struct devfs_entry *de)
{
- struct devfs_entry *child;
+ int unhooked = _devfs_unhook (de);

- if ( (child = de->slave) != NULL )
- {
- de->slave = NULL; /* Unhook first in case slave is parent directory */
- unregister (child);
- }
- if (de->registered)
- {
- devfsd_notify (de, DEVFSD_NOTIFY_UNREGISTERED, 0);
- free_dentries (de);
- }
- de->info = NULL;
- if ( S_ISCHR (de->mode) || S_ISBLK (de->mode) || S_ISREG (de->mode) )
- {
- de->registered = FALSE;
- de->u.fcb.ops = NULL;
- if (!S_ISREG (de->mode) && de->u.fcb.autogen)
- {
- devfs_dealloc_devnum ( S_ISCHR (de->mode) ? DEVFS_SPECIAL_CHR :
- DEVFS_SPECIAL_BLK,
- MKDEV (de->u.fcb.u.device.major,
- de->u.fcb.u.device.minor) );
- }
- de->u.fcb.autogen = FALSE;
- return;
- }
- if (S_ISLNK (de->mode) && de->registered)
- {
- de->registered = FALSE;
- down_write (&symlink_rwsem);
- if (de->u.symlink.linkname) kfree (de->u.symlink.linkname);
- de->u.symlink.linkname = NULL;
- up_write (&symlink_rwsem);
- return;
- }
- if ( S_ISFIFO (de->mode) )
- {
- de->registered = FALSE;
- return;
- }
- if (!de->registered) return;
- if ( !S_ISDIR (de->mode) )
- {
- printk ("%s: unregister(): unsupported type\n", DEVFS_NAME);
- return;
- }
- de->registered = FALSE;
- /* Now recursively search the subdirectories: this is a stack chomper */
- for (child = de->u.dir.first; child != NULL; child = child->next)
- {
+ write_unlock (&dir->u.dir.lock);
+ if (!unhooked) return;
+ devfs_get (dir);
+ devfs_unregister (de->slave); /* Let it handle the locking */
+ devfsd_notify (de, DEVFSD_NOTIFY_UNREGISTERED, 0);
+ free_dentries (de);
+ devfs_put (dir);
+ if ( !S_ISDIR (de->mode) ) return;
+ while (TRUE) /* Recursively unregister: this is a stack chomper */
+ {
+ struct devfs_entry *child;
+
+ write_lock (&de->u.dir.lock);
+ de->u.dir.no_more_additions = TRUE;
+ child = de->u.dir.first;
+ unregister (de, child);
+ if (!child) break;
#ifdef CONFIG_DEVFS_DEBUG
if (devfs_debug & DEBUG_UNREGISTER)
printk ("%s: unregister(): child->name: \"%s\" child: %p\n",
DEVFS_NAME, child->name, child);
#endif
- unregister (child);
+ devfs_put (child);
}
} /* End Function unregister */

@@ -1484,20 +1632,21 @@

void devfs_unregister (devfs_handle_t de)
{
- if (de == NULL) return;
+ if ( (de == NULL) || (de->parent == NULL) ) return;
#ifdef CONFIG_DEVFS_DEBUG
if (devfs_debug & DEBUG_UNREGISTER)
printk ("%s: devfs_unregister(): de->name: \"%s\" de: %p\n",
DEVFS_NAME, de->name, de);
#endif
- unregister (de);
+ write_lock (&de->parent->u.dir.lock);
+ unregister (de->parent, de);
+ devfs_put (de);
} /* End Function devfs_unregister */

static int devfs_do_symlink (devfs_handle_t dir, const char *name,
unsigned int flags, const char *link,
devfs_handle_t *handle, void *info)
{
- int is_new;
unsigned int linklength;
char *newlink;
struct devfs_entry *de;
@@ -1522,28 +1671,27 @@
return -ENOMEM;
memcpy (newlink, link, linklength);
newlink[linklength] = '\0';
- if ( ( de = search_for_entry (dir, name, strlen (name), TRUE, TRUE,
- &is_new, FALSE) ) == NULL )
+ if ( ( de = _devfs_prepare_leaf (&dir, name) ) == NULL )
{
- kfree (newlink);
- return -ENOMEM;
- }
- down_write (&symlink_rwsem);
- if (de->registered)
- {
- up_write (&symlink_rwsem);
- kfree (newlink);
- printk ("%s: devfs_do_symlink(%s): entry already exists\n",
+ printk ("%s: devfs_do_symlink(%s): could not prepare leaf\n",
DEVFS_NAME, name);
- return -EEXIST;
+ kfree (newlink);
+ return -ENOTDIR;
}
de->mode = S_IFLNK | S_IRUGO | S_IXUGO;
de->info = info;
de->hide = (flags & DEVFS_FL_HIDE) ? TRUE : FALSE;
de->u.symlink.linkname = newlink;
de->u.symlink.length = linklength;
- de->registered = TRUE;
- up_write (&symlink_rwsem);
+ if ( append_entry (dir, de) )
+ {
+ printk ("%s: devfs_do_symlink(%s): could not append to parent\n",
+ DEVFS_NAME, name);
+ devfs_put (de);
+ devfs_put (dir);
+ return -EEXIST;
+ }
+ devfs_put (dir);
if (handle != NULL) *handle = de;
return 0;
} /* End Function devfs_do_symlink */
@@ -1593,7 +1741,6 @@

devfs_handle_t devfs_mk_dir (devfs_handle_t dir, const char *name, void *info)
{
- int is_new;
struct devfs_entry *de;

if (name == NULL)
@@ -1601,36 +1748,28 @@
printk ("%s: devfs_mk_dir(): NULL name pointer\n", DEVFS_NAME);
return NULL;
}
- de = search_for_entry (dir, name, strlen (name), TRUE, TRUE, &is_new,
- FALSE);
- if (de == NULL)
+ if ( ( de = _devfs_prepare_leaf (&dir, name) ) == NULL )
{
- printk ("%s: devfs_mk_dir(): could not create entry: \"%s\"\n",
+ printk ("%s: devfs_mk_dir(%s): could not prepare leaf\n",
DEVFS_NAME, name);
return NULL;
}
- if (!S_ISDIR (de->mode) && de->registered)
+ de->mode = S_IFDIR | S_IRUGO | S_IXUGO;
+ de->info = info;
+ rwlock_init (&de->u.dir.lock);
+ if ( append_entry (dir, de) )
{
- printk ("%s: devfs_mk_dir(): existing non-directory entry: \"%s\"\n",
+ printk ("%s: devfs_mk_dir(%s): could not append to parent\n",
DEVFS_NAME, name);
+ devfs_put (de);
+ devfs_put (dir);
return NULL;
}
#ifdef CONFIG_DEVFS_DEBUG
if (devfs_debug & DEBUG_REGISTER)
- printk ("%s: devfs_mk_dir(%s): de: %p %s\n",
- DEVFS_NAME, name, de, is_new ? "new" : "existing");
+ printk ("%s: devfs_mk_dir(%s): de: %p\n", DEVFS_NAME, name, de);
#endif
- if (!S_ISDIR (de->mode) && !is_new)
- {
- /* Transmogrifying an old entry */
- de->u.dir.first = NULL;
- de->u.dir.last = NULL;
- }
- de->mode = S_IFDIR | S_IRUGO | S_IXUGO;
- de->info = info;
- if (!de->registered) de->u.dir.num_removable = 0;
- de->hide = FALSE;
- de->registered = TRUE;
+ devfs_put (dir);
return de;
} /* End Function devfs_mk_dir */

@@ -1659,9 +1798,9 @@
devfs_handle_t de;

if ( (name != NULL) && (name[0] == '\0') ) name = NULL;
- de = find_entry (dir, name, 0, major, minor, type, traverse_symlinks);
+ de = find_entry (dir, name, 0, major, minor, type,
+ traverse_symlinks);
if (de == NULL) return NULL;
- if (!de->registered) return NULL;
return de;
} /* End Function devfs_find_handle */

@@ -1679,7 +1818,6 @@
unsigned int fl = 0;

if (de == NULL) return -EINVAL;
- if (!de->registered) return -ENODEV;
if (de->hide) fl |= DEVFS_FL_HIDE;
if ( S_ISCHR (de->mode) || S_ISBLK (de->mode) || S_ISREG (de->mode) )
{
@@ -1703,7 +1841,6 @@
int devfs_set_flags (devfs_handle_t de, unsigned int flags)
{
if (de == NULL) return -EINVAL;
- if (!de->registered) return -ENODEV;
#ifdef CONFIG_DEVFS_DEBUG
if (devfs_debug & DEBUG_SET_FLAGS)
printk ("%s: devfs_set_flags(): de->name: \"%s\"\n",
@@ -1742,7 +1879,6 @@
unsigned int *minor)
{
if (de == NULL) return -EINVAL;
- if (!de->registered) return -ENODEV;
if ( S_ISDIR (de->mode) ) return -EISDIR;
if ( !S_ISCHR (de->mode) && !S_ISBLK (de->mode) ) return -EINVAL;
if (major != NULL) *major = de->u.fcb.u.device.major;
@@ -1808,7 +1944,6 @@
void *devfs_get_ops (devfs_handle_t de)
{
if (de == NULL) return NULL;
- if (!de->registered) return NULL;
if ( S_ISCHR (de->mode) || S_ISBLK (de->mode) || S_ISREG (de->mode) )
return de->u.fcb.ops;
return NULL;
@@ -1826,7 +1961,6 @@
int devfs_set_file_size (devfs_handle_t de, unsigned long size)
{
if (de == NULL) return -EINVAL;
- if (!de->registered) return -EINVAL;
if ( !S_ISREG (de->mode) ) return -EINVAL;
if (de->u.fcb.u.file.size == size) return 0;
de->u.fcb.u.file.size = size;
@@ -1846,7 +1980,6 @@
void *devfs_get_info (devfs_handle_t de)
{
if (de == NULL) return NULL;
- if (!de->registered) return NULL;
return de->info;
} /* End Function devfs_get_info */

@@ -1861,7 +1994,6 @@
int devfs_set_info (devfs_handle_t de, void *info)
{
if (de == NULL) return -EINVAL;
- if (!de->registered) return -EINVAL;
de->info = info;
return 0;
} /* End Function devfs_set_info */
@@ -1876,7 +2008,6 @@
devfs_handle_t devfs_get_parent (devfs_handle_t de)
{
if (de == NULL) return NULL;
- if (!de->registered) return NULL;
return de->parent;
} /* End Function devfs_get_parent */

@@ -1891,7 +2022,6 @@
devfs_handle_t devfs_get_first_child (devfs_handle_t de)
{
if (de == NULL) return NULL;
- if (!de->registered) return NULL;
if ( !S_ISDIR (de->mode) ) return NULL;
return de->u.dir.first;
} /* End Function devfs_get_first_child */
@@ -1907,7 +2037,6 @@
devfs_handle_t devfs_get_next_sibling (devfs_handle_t de)
{
if (de == NULL) return NULL;
- if (!de->registered) return NULL;
return de->next;
} /* End Function devfs_get_next_sibling */

@@ -1961,7 +2090,6 @@
const char *devfs_get_name (devfs_handle_t de, unsigned int *namelen)
{
if (de == NULL) return NULL;
- if (!de->registered) return NULL;
if (namelen != NULL) *namelen = de->namelen;
return de->name;
} /* End Function devfs_get_name */
@@ -2059,6 +2187,7 @@
{"dunreg", DEBUG_UNREGISTER, &devfs_debug_init},
{"diget", DEBUG_I_GET, &devfs_debug_init},
{"dchange", DEBUG_SET_FLAGS, &devfs_debug_init},
+ {"dsread", DEBUG_S_READ, &devfs_debug_init},
{"dichange", DEBUG_I_CHANGE, &devfs_debug_init},
{"dimknod", DEBUG_I_MKNOD, &devfs_debug_init},
{"dilookup", DEBUG_I_LOOKUP, &devfs_debug_init},
@@ -2129,13 +2258,13 @@


/**
- * try_modload - Notify devfsd of an inode lookup.
+ * try_modload - Notify devfsd of an inode lookup by a non-devfsd process.
* @parent: The parent devfs entry.
* @fs_info: The filesystem info.
* @name: The device name.
* @namelen: The number of characters in @name.
- * @buf: A working area that will be used. This must not go out of scope until
- * devfsd is idle again.
+ * @buf: A working area that will be used. This must not go out of scope
+ * until devfsd is idle again.
*
* Returns 0 on success, else a negative error code.
*/
@@ -2206,7 +2335,6 @@
if (dir->u.dir.num_removable < 1) return;
for (de = dir->u.dir.first; de != NULL; de = de->next)
{
- if (!de->registered) continue;
if ( !S_ISBLK (de->mode) ) continue;
if (!de->u.fcb.removable) continue;
check_disc_changed (de);
@@ -2229,7 +2357,6 @@

for (de = dir->u.dir.first; de != NULL; de = de->next)
{
- if (!de->registered) continue;
if ( !S_ISBLK (de->mode) ) continue;
if (!de->u.fcb.removable) continue;
if (strcmp (de->name, "disc") == 0) return check_disc_changed (de);
@@ -2283,8 +2410,8 @@
de->inode.mtime = inode->i_mtime;
de->inode.ctime = inode->i_ctime;
if ( iattr->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID) )
- devfsd_notify_one (de, DEVFSD_NOTIFY_CHANGE, inode->i_mode,
- inode->i_uid, inode->i_gid, fs_info);
+ devfsd_notify_de (de, DEVFSD_NOTIFY_CHANGE, inode->i_mode,
+ inode->i_uid, inode->i_gid, fs_info);
return 0;
} /* End Function devfs_notify_change */

@@ -2299,11 +2426,10 @@
return 0;
} /* End Function devfs_statfs */

-static void devfs_clear_inode(struct inode *inode)
+static void devfs_clear_inode (struct inode *inode)
{
- if (S_ISBLK(inode->i_mode))
- bdput(inode->i_bdev);
-}
+ if ( S_ISBLK (inode->i_mode) ) bdput (inode->i_bdev);
+} /* End Function devfs_clear_inode */

static struct super_operations devfs_sops =
{
@@ -2319,7 +2445,8 @@
* @de: The devfs inode.
* @dentry: The dentry to register with the devfs inode.
*
- * Returns the inode on success, else %NULL.
+ * Returns the inode on success, else %NULL. An implicit devfs_get() is
+ * performed if the inode is created.
*/

static struct inode *get_vfs_inode (struct super_block *sb,
@@ -2344,7 +2471,7 @@
return NULL;
}
de->inode.dentry = dentry;
- inode->u.generic_ip = de;
+ inode->u.generic_ip = devfs_get (de);
inode->i_ino = de->inode.ino;
#ifdef CONFIG_DEVFS_DEBUG
if (devfs_debug & DEBUG_I_GET)
@@ -2366,7 +2493,7 @@
{
inode->i_rdev = MKDEV (de->u.fcb.u.device.major,
de->u.fcb.u.device.minor);
- if (bd_acquire(inode) == 0)
+ if (bd_acquire (inode) == 0)
{
if (!inode->i_bdev->bd_op && de->u.fcb.ops)
inode->i_bdev->bd_op = de->u.fcb.ops;
@@ -2409,7 +2536,7 @@
int err, count;
int stored = 0;
struct fs_info *fs_info;
- struct devfs_entry *parent, *de;
+ struct devfs_entry *parent, *de, *next = NULL;
struct inode *inode = file->f_dentry->d_inode;

fs_info = inode->i_sb->u.generic_sbp;
@@ -2441,19 +2568,32 @@
default:
/* Skip entries */
count = file->f_pos - 2;
- for (de = parent->u.dir.first; (de != NULL) && (count > 0);
- de = de->next)
+ read_lock (&parent->u.dir.lock);
+ for (de = parent->u.dir.first; de && (count > 0); de = de->next)
if ( !IS_HIDDEN (de) ) --count;
+ devfs_get (de);
+ read_unlock (&parent->u.dir.lock);
/* Now add all remaining entries */
- for (; de != NULL; de = de->next)
+ while (de)
{
- if ( IS_HIDDEN (de) ) continue;
- err = (*filldir) (dirent, de->name, de->namelen,
- file->f_pos, de->inode.ino, de->mode >> 12);
+ if ( IS_HIDDEN (de) ) err = 0;
+ else
+ {
+ err = (*filldir) (dirent, de->name, de->namelen,
+ file->f_pos, de->inode.ino, de->mode >> 12);
+ if (err >= 0)
+ {
+ file->f_pos++;
+ ++stored;
+ }
+ }
+ read_lock (&parent->u.dir.lock);
+ next = devfs_get (de->next);
+ read_unlock (&parent->u.dir.lock);
+ devfs_put (de);
+ de = next;
if (err == -EINVAL) break;
if (err < 0) return err;
- file->f_pos++;
- ++stored;
}
break;
}
@@ -2467,14 +2607,9 @@
struct devfs_entry *de;
struct fs_info *fs_info = inode->i_sb->u.generic_sbp;

- lock_kernel ();
de = get_devfs_entry_from_vfs_inode (inode, TRUE);
- err = -ENODEV;
- if (de == NULL)
- goto out;
- err = 0;
- if ( S_ISDIR (de->mode) )
- goto out;
+ if (de == NULL) return -ENODEV;
+ if ( S_ISDIR (de->mode) ) return 0;
df = &de->u.fcb;
file->private_data = de->info;
if ( S_ISBLK (inode->i_mode) )
@@ -2482,7 +2617,7 @@
file->f_op = &def_blk_fops;
if (df->ops) inode->i_bdev->bd_op = df->ops;
}
- else file->f_op = fops_get ( (struct file_operations*) df->ops );
+ 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
@@ -2491,10 +2626,9 @@
if ( S_ISCHR (inode->i_mode) ) err = chrdev_open (inode, file);
else err = -ENODEV;
}
- if (err < 0) goto out;
+ if (err < 0) return err;
/* Open was successful */
- err = 0;
- if (df->open) goto out;
+ if (df->open) return 0;
df->open = TRUE; /* This is the first open */
if (df->auto_owner)
{
@@ -2507,23 +2641,21 @@
inode->i_gid = de->inode.gid;
}
if (df->aopen_notify)
- devfsd_notify_one (de, DEVFSD_NOTIFY_ASYNC_OPEN, inode->i_mode,
- current->euid, current->egid, fs_info);
-out:
- unlock_kernel ();
- return err;
+ devfsd_notify_de (de, DEVFSD_NOTIFY_ASYNC_OPEN, inode->i_mode,
+ current->euid, current->egid, fs_info);
+ return 0;
} /* End Function devfs_open */

static struct file_operations devfs_fops =
{
- open: devfs_open,
+ open: devfs_open,
};

static struct file_operations devfs_dir_fops =
{
- read: generic_read_dir,
+ read: generic_read_dir,
readdir: devfs_readdir,
- open: devfs_open,
+ open: devfs_open,
};


@@ -2556,15 +2688,17 @@
{
struct devfs_entry *de;

- lock_kernel ();
de = get_devfs_entry_from_vfs_inode (inode, FALSE);
#ifdef CONFIG_DEVFS_DEBUG
if (devfs_debug & DEBUG_D_IPUT)
printk ("%s: d_iput(): dentry: %p inode: %p de: %p de->dentry: %p\n",
DEVFS_NAME, dentry, inode, de, de->inode.dentry);
#endif
- if (de->inode.dentry == dentry) de->inode.dentry = NULL;
- unlock_kernel ();
+ if (de->inode.dentry == dentry) /*FIXME: do I need this test? */
+ {
+ de->inode.dentry = NULL;
+ devfs_put (de);
+ }
iput (inode);
} /* End Function devfs_d_iput */

@@ -2622,8 +2756,8 @@
if (!de->u.fcb.open) return 0;
de->u.fcb.open = FALSE;
if (de->u.fcb.aopen_notify)
- devfsd_notify_one (de, DEVFSD_NOTIFY_CLOSE, inode->i_mode,
- current->euid, current->egid, fs_info);
+ devfsd_notify_de (de, DEVFSD_NOTIFY_CLOSE, inode->i_mode,
+ current->euid, current->egid, fs_info);
if (!de->u.fcb.auto_owner) return 0;
/* Change the ownership/protection back */
de->inode.mode = (de->inode.mode & ~S_IALLUGO) | S_IRUGO | S_IWUGO;
@@ -2641,10 +2775,9 @@
struct inode *dir;
struct fs_info *fs_info;

- lock_kernel ();
dir = dentry->d_parent->d_inode;
fs_info = dir->i_sb->u.generic_sbp;
- if (!de || de->registered)
+ if (!de)
{
if ( !dentry->d_inode && is_devfsd_or_child (fs_info) )
{
@@ -2666,30 +2799,28 @@
devfs_handle_t parent;

parent = get_devfs_entry_from_vfs_inode (dir, TRUE);
- de = search_for_entry_in_dir (parent, dentry->d_name.name,
- dentry->d_name.len, FALSE);
+ de = _devfs_search_dir (parent, dentry->d_name.name,
+ dentry->d_name.len);
}
- if (de == NULL) goto out;
+ if (de == NULL) return 1;
/* Create an inode, now that the driver information is available
*/
- if (de->no_persistence) update_devfs_inode_from_entry (de);
- else if (de->inode.ctime == 0) update_devfs_inode_from_entry (de);
+ if (de->inode.ctime == 0) update_devfs_inode_from_entry (de);
else de->inode.mode =
(de->mode & ~S_IALLUGO) | (de->inode.mode & S_IALLUGO);
- if ( ( inode = get_vfs_inode (dir->i_sb, de, dentry) ) == NULL )
- goto out;
+ inode = get_vfs_inode (dir->i_sb, de, dentry);
+ devfs_put (de);
+ if (!inode) return 1;
#ifdef CONFIG_DEVFS_DEBUG
if (devfs_debug & DEBUG_I_LOOKUP)
printk ("%s: d_revalidate(): new VFS inode(%u): %p devfs_entry: %p\n",
DEVFS_NAME, de->inode.ino, inode, de);
#endif
d_instantiate (dentry, inode);
- goto out;
+ return 1;
}
}
if ( wait_for_devfsd_finished (fs_info) ) dentry->d_op = &devfs_dops;
-out:
- unlock_kernel ();
return 1;
} /* End Function devfs_d_revalidate_wait */

@@ -2719,20 +2850,19 @@
DEVFS_NAME, txt, dentry, parent, current->comm);
#endif
if (parent == NULL) return ERR_PTR (-ENOENT);
- /* Try to reclaim an existing devfs entry */
- de = search_for_entry_in_dir (parent,
- dentry->d_name.name, dentry->d_name.len,
- FALSE);
- if ( ( (de == NULL) || !de->registered ) &&
- (parent->u.dir.num_removable > 0) &&
+ 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) )
{
- if (de == NULL)
- de = search_for_entry_in_dir (parent, dentry->d_name.name,
- dentry->d_name.len, FALSE);
+ 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) || !de->registered )
+ if (de == NULL)
{
/* Try with devfsd. For any kind of failure, leave a negative dentry
so someone else can deal with it (in the case where the sysadmin
@@ -2747,7 +2877,6 @@
}
/* devfsd claimed success */
dentry->d_op = &devfs_wait_dops;
- dentry->d_fsdata = de;
d_add (dentry, NULL); /* Open the floodgates */
/* Unlock directory semaphore, which will release any waiters. They
will get the hashed dentry, and may be forced to wait for
@@ -2758,10 +2887,10 @@
/* If someone else has been so kind as to make the inode, we go home
early */
if (dentry->d_inode) return NULL;
- if (de && !de->registered) return NULL;
- if (de == NULL)
- de = search_for_entry_in_dir (parent, dentry->d_name.name,
- dentry->d_name.len, FALSE);
+ 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) return NULL;
/* OK, there's an entry now, but no VFS inode yet */
}
@@ -2771,12 +2900,12 @@
d_add (dentry, NULL); /* Open the floodgates */
}
/* Create an inode, now that the driver information is available */
- if (de->no_persistence) update_devfs_inode_from_entry (de);
- else if (de->inode.ctime == 0) update_devfs_inode_from_entry (de);
+ if (de->inode.ctime == 0) update_devfs_inode_from_entry (de);
else de->inode.mode =
(de->mode & ~S_IALLUGO) | (de->inode.mode & S_IALLUGO);
- if ( ( inode = get_vfs_inode (dir->i_sb, de, dentry) ) == NULL )
- return ERR_PTR (-ENOMEM);
+ inode = get_vfs_inode (dir->i_sb, de, dentry);
+ devfs_put (de);
+ if (!inode) return ERR_PTR (-ENOMEM);
#ifdef CONFIG_DEVFS_DEBUG
if (devfs_debug & DEBUG_I_LOOKUP)
printk ("%s: lookup(): new VFS inode(%u): %p devfs_entry: %p\n",
@@ -2794,6 +2923,7 @@

static int devfs_unlink (struct inode *dir, struct dentry *dentry)
{
+ int unhooked;
struct devfs_entry *de;
struct inode *inode = dentry->d_inode;

@@ -2809,20 +2939,17 @@
}
#endif

- de = get_devfs_entry_from_vfs_inode (dentry->d_inode, TRUE);
+ de = get_devfs_entry_from_vfs_inode (inode, TRUE);
if (de == NULL) return -ENOENT;
- devfsd_notify_one (de, DEVFSD_NOTIFY_DELETE, inode->i_mode,
- inode->i_uid, inode->i_gid, dir->i_sb->u.generic_sbp);
- de->registered = FALSE;
- de->hide = TRUE;
- if ( S_ISLNK (de->mode) )
- {
- down_write (&symlink_rwsem);
- if (de->u.symlink.linkname) kfree (de->u.symlink.linkname);
- de->u.symlink.linkname = NULL;
- up_write (&symlink_rwsem);
- }
+ if (!de->vfs_created) return -EPERM;
+ write_lock (&de->parent->u.dir.lock);
+ unhooked = _devfs_unhook (de);
+ write_unlock (&de->parent->u.dir.lock);
+ if (!unhooked) return -ENOENT;
+ devfsd_notify_de (de, DEVFSD_NOTIFY_DELETE, inode->i_mode,
+ inode->i_uid, inode->i_gid, dir->i_sb->u.generic_sbp);
free_dentries (de);
+ devfs_put (de);
return 0;
} /* End Function devfs_unlink */

@@ -2846,6 +2973,7 @@
DEVFS_NAME, err);
#endif
if (err < 0) return err;
+ de->vfs_created = TRUE;
de->inode.mode = de->mode;
de->inode.atime = CURRENT_TIME;
de->inode.mtime = CURRENT_TIME;
@@ -2857,50 +2985,38 @@
printk ("%s: symlink(): new VFS inode(%u): %p dentry: %p\n",
DEVFS_NAME, de->inode.ino, inode, dentry);
#endif
- de->hide = FALSE;
d_instantiate (dentry, inode);
- devfsd_notify_one (de, DEVFSD_NOTIFY_CREATE, inode->i_mode,
- inode->i_uid, inode->i_gid, fs_info);
+ devfsd_notify_de (de, DEVFSD_NOTIFY_CREATE, inode->i_mode,
+ inode->i_uid, inode->i_gid, fs_info);
return 0;
} /* End Function devfs_symlink */

static int devfs_mkdir (struct inode *dir, struct dentry *dentry, int mode)
{
- int is_new;
struct fs_info *fs_info;
struct devfs_entry *parent, *de;
struct inode *inode;

mode = (mode & ~S_IFMT) | S_IFDIR;
fs_info = dir->i_sb->u.generic_sbp;
- /* First try to get the devfs entry for this directory */
parent = get_devfs_entry_from_vfs_inode (dir, TRUE);
if (parent == NULL) return -ENOENT;
- /* Try to reclaim an existing devfs entry, create if there isn't one */
- de = search_for_entry (parent, dentry->d_name.name, dentry->d_name.len,
- FALSE, TRUE, &is_new, FALSE);
- if (de == NULL) return -ENOMEM;
- if (de->registered)
+ de = _devfs_alloc_dir (dentry->d_name.name, dentry->d_name.len);
+ if (!de) return -ENOMEM;
+ de->vfs_created = TRUE;
+ de->mode = mode;
+ if ( append_entry (parent, de) )
{
- printk ("%s: mkdir(): existing entry\n", DEVFS_NAME);
+ devfs_put (de);
+ printk ("%s: mkdir(): existing devfs entry\n", DEVFS_NAME);
return -EEXIST;
}
- de->hide = FALSE;
- if (!S_ISDIR (de->mode) && !is_new)
- {
- /* Transmogrifying an old entry */
- de->u.dir.first = NULL;
- de->u.dir.last = NULL;
- }
- de->mode = mode;
- de->u.dir.num_removable = 0;
de->inode.mode = mode;
de->inode.uid = current->euid;
de->inode.gid = current->egid;
de->inode.atime = CURRENT_TIME;
de->inode.mtime = CURRENT_TIME;
de->inode.ctime = CURRENT_TIME;
- de->registered = TRUE;
if ( ( inode = get_vfs_inode (dir->i_sb, de, dentry) ) == NULL )
return -ENOMEM;
#ifdef CONFIG_DEVFS_DEBUG
@@ -2909,16 +3025,16 @@
DEVFS_NAME, de->inode.ino, inode, dentry);
#endif
d_instantiate (dentry, inode);
- devfsd_notify_one (de, DEVFSD_NOTIFY_CREATE, inode->i_mode,
- inode->i_uid, inode->i_gid, fs_info);
+ devfsd_notify_de (de, DEVFSD_NOTIFY_CREATE, inode->i_mode,
+ inode->i_uid, inode->i_gid, fs_info);
return 0;
} /* End Function devfs_mkdir */

static int devfs_rmdir (struct inode *dir, struct dentry *dentry)
{
- int has_children = FALSE;
+ int err = 0;
+ struct devfs_entry *de;
struct fs_info *fs_info;
- struct devfs_entry *de, *child;
struct inode *inode = dentry->d_inode;

if (dir->i_sb->u.generic_sbp != inode->i_sb->u.generic_sbp) return -EINVAL;
@@ -2926,27 +3042,28 @@
de = get_devfs_entry_from_vfs_inode (inode, TRUE);
if (de == NULL) return -ENOENT;
if ( !S_ISDIR (de->mode) ) return -ENOTDIR;
- for (child = de->u.dir.first; child != NULL; child = child->next)
- {
- if (child->registered)
- {
- has_children = TRUE;
- break;
- }
- }
- if (has_children) return -ENOTEMPTY;
- devfsd_notify_one (de, DEVFSD_NOTIFY_DELETE, inode->i_mode,
- inode->i_uid, inode->i_gid, fs_info);
- de->hide = TRUE;
- de->registered = FALSE;
+ if (!de->vfs_created) return -EPERM;
+ /* First ensure the directory is empty and will stay thay way */
+ write_lock (&de->u.dir.lock);
+ de->u.dir.no_more_additions = TRUE;
+ if (de->u.dir.first) err = -ENOTEMPTY;
+ write_unlock (&de->u.dir.lock);
+ if (err) return err;
+ /* Now unhook the directory from it's parent */
+ write_lock (&de->parent->u.dir.lock);
+ if ( !_devfs_unhook (de) ) err = -ENOENT;
+ write_unlock (&de->parent->u.dir.lock);
+ if (err) return err;
+ devfsd_notify_de (de, DEVFSD_NOTIFY_DELETE, inode->i_mode,
+ inode->i_uid, inode->i_gid, fs_info);
free_dentries (de);
+ devfs_put (de);
return 0;
} /* End Function devfs_rmdir */

static int devfs_mknod (struct inode *dir, struct dentry *dentry, int mode,
int rdev)
{
- int is_new;
struct fs_info *fs_info;
struct devfs_entry *parent, *de;
struct inode *inode;
@@ -2963,21 +3080,12 @@
DEVFS_NAME, txt, mode, rdev);
}
#endif
-
fs_info = dir->i_sb->u.generic_sbp;
- /* First try to get the devfs entry for this directory */
parent = get_devfs_entry_from_vfs_inode (dir, TRUE);
if (parent == NULL) return -ENOENT;
- /* Try to reclaim an existing devfs entry, create if there isn't one */
- de = search_for_entry (parent, dentry->d_name.name, dentry->d_name.len,
- FALSE, TRUE, &is_new, FALSE);
- if (de == NULL) return -ENOMEM;
- if (de->registered)
- {
- printk ("%s: mknod(): existing entry\n", DEVFS_NAME);
- return -EEXIST;
- }
- de->info = NULL;
+ de = _devfs_alloc_entry (dentry->d_name.name, dentry->d_name.len);
+ if (!de) return -ENOMEM;
+ de->vfs_created = TRUE;
de->mode = mode;
if ( S_ISBLK (mode) || S_ISCHR (mode) )
{
@@ -2995,14 +3103,18 @@
de->u.fifo.uid = current->euid;
de->u.fifo.gid = current->egid;
}
- de->hide = FALSE;
+ if ( append_entry (parent, de) )
+ {
+ devfs_put (de);
+ printk ("%s: mknod(): existing devfs entry\n", DEVFS_NAME);
+ return -EEXIST;
+ }
de->inode.mode = mode;
de->inode.uid = current->euid;
de->inode.gid = current->egid;
de->inode.atime = CURRENT_TIME;
de->inode.mtime = CURRENT_TIME;
de->inode.ctime = CURRENT_TIME;
- de->registered = TRUE;
if ( ( inode = get_vfs_inode (dir->i_sb, de, dentry) ) == NULL )
return -ENOMEM;
#ifdef CONFIG_DEVFS_DEBUG
@@ -3011,8 +3123,8 @@
DEVFS_NAME, de->inode.ino, inode, dentry);
#endif
d_instantiate (dentry, inode);
- devfsd_notify_one (de, DEVFSD_NOTIFY_CREATE, inode->i_mode,
- inode->i_uid, inode->i_gid, fs_info);
+ devfsd_notify_de (de, DEVFSD_NOTIFY_CREATE, inode->i_mode,
+ inode->i_uid, inode->i_gid, fs_info);
return 0;
} /* End Function devfs_mknod */

@@ -3023,10 +3135,7 @@

de = get_devfs_entry_from_vfs_inode (dentry->d_inode, TRUE);
if (!de) return -ENODEV;
- down_read (&symlink_rwsem);
- err = de->registered ? vfs_readlink (dentry, buffer, buflen,
- de->u.symlink.linkname) : -ENODEV;
- up_read (&symlink_rwsem);
+ err = vfs_readlink (dentry, buffer, buflen, de->u.symlink.linkname);
return err;
} /* End Function devfs_readlink */

@@ -3034,25 +3143,10 @@
{
int err;
struct devfs_entry *de;
- char *copy;

de = get_devfs_entry_from_vfs_inode (dentry->d_inode, TRUE);
if (!de) return -ENODEV;
- down_read (&symlink_rwsem);
- if (!de->registered)
- {
- up_read (&symlink_rwsem);
- return -ENODEV;
- }
- copy = kmalloc (de->u.symlink.length + 1, GFP_KERNEL);
- if (copy) memcpy (copy, de->u.symlink.linkname, de->u.symlink.length + 1);
- up_read (&symlink_rwsem);
- if (copy)
- {
- err = vfs_follow_link (nd, copy);
- kfree (copy);
- }
- else err = -ENOMEM;
+ err = vfs_follow_link (nd, de->u.symlink.linkname);
return err;
} /* End Function devfs_follow_link */

@@ -3084,7 +3178,7 @@
{
struct inode *root_inode = NULL;

- if (get_root_entry () == NULL) goto out_no_root;
+ if (_devfs_get_root_entry () == NULL) goto out_no_root;
atomic_set (&fs_info.devfsd_overrun_count, 0);
init_waitqueue_head (&fs_info.devfsd_wait_queue);
init_waitqueue_head (&fs_info.revalidate_wait_queue);
@@ -3099,7 +3193,7 @@
sb->s_root = d_alloc_root (root_inode);
if (!sb->s_root) goto out_no_root;
#ifdef CONFIG_DEVFS_DEBUG
- if (devfs_debug & DEBUG_DISABLED)
+ if (devfs_debug & DEBUG_S_READ)
printk ("%s: read super, made devfs ptr: %p\n",
DEVFS_NAME, sb->u.generic_sbp);
#endif
@@ -3182,6 +3276,7 @@
if (pos < 0) return pos;
info->namelen = DEVFS_PATHLEN - pos - 1;
if (info->mode == 0) info->mode = de->mode;
+ for (; de != NULL; de = de->parent) devfs_put (de);
}
devname_offset = info->devname - (char *) info;
rpos = *ppos;
-
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