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Subject[PATCH] Next cut of new devfs core
  Hi, all. Another cut of the new devfs core. More locking fixes and
code cleanups.

If people could try this out and report back, I'd appreciate it.

Patch against 2.4.14, and should apply cleanly against 2.4.15-pre4.

Regards,

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

diff -urN linux-2.4.14/Documentation/filesystems/devfs/README linux/Documentation/filesystems/devfs/README
--- linux-2.4.14/Documentation/filesystems/devfs/README Thu Oct 11 00:23:24 2001
+++ linux/Documentation/filesystems/devfs/README Sat Nov 10 19:44:15 2001
@@ -3,7 +3,7 @@

Linux Devfs (Device File System) FAQ
Richard Gooch
-29-SEP-2001
+9-NOV-2001

-----------------------------------------------------------------------------

@@ -11,7 +11,9 @@

http://www.atnf.csiro.au/~rgooch/linux/docs/devfs.html
and looks much better than the text version distributed with the
-kernel sources.
+kernel sources. A mirror site is available at:
+
+http://www.ras.ucalgary.ca/~rgooch/linux/docs/devfs.html

There is also an optional daemon that may be used with devfs. You can
find out more about it at:
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 Mon Nov 12 17:59:18 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
+ 20011112 Richard Gooch <rgooch@atnf.csiro.au>
+ Pre-alpha cut of new locking code.
+ v1.0-pre6
*/
#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-pre6 (20011112)"

#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; /* Lock for writing but not reading */
+ unsigned char no_more_additions:1;
};

struct file_type
@@ -656,8 +652,6 @@

struct fcb_type /* File, char, block type */
{
- uid_t default_uid;
- gid_t default_gid;
void *ops;
union
{
@@ -678,20 +672,13 @@
char *linkname; /* This is NULL-terminated */
};

-struct fifo_type
-{
- uid_t uid;
- gid_t gid;
-};
-
-struct devfs_inode /* This structure is for "persistent" inode storage */
+struct devfs_inode /* This structure is for "persistent" inode storage */
{
+ struct dentry *dentry;
time_t atime;
time_t mtime;
time_t ctime;
- unsigned int ino; /* Inode number as seen in the VFS */
- struct dentry *dentry;
- umode_t mode;
+ unsigned int ino; /* Inode number as seen in the VFS */
uid_t uid;
gid_t gid;
};
@@ -699,12 +686,12 @@
struct devfs_entry
{
void *info;
+ atomic_t refcount; /* When this drops to zero, it's unused */
union
{
struct directory_type dir;
struct fcb_type fcb;
struct symlink_type symlink;
- struct fifo_type fifo;
}
u;
struct devfs_entry *prev; /* Previous entry in the parent directory */
@@ -713,12 +700,11 @@
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 +719,7 @@
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;
@@ -755,6 +741,9 @@
#ifdef CONFIG_DEVFS_DEBUG
static unsigned int devfs_debug_init __initdata = DEBUG_NONE;
static unsigned int devfs_debug = DEBUG_NONE;
+static spinlock_t stat_lock = SPIN_LOCK_UNLOCKED;
+static unsigned int stat_num_entries;
+static unsigned int stat_num_bytes;
#endif

#ifdef CONFIG_DEVFS_MOUNT
@@ -763,19 +752,23 @@
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,
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 struct file_operations stat_fops =
+{
+ read: stat_read,
+};
+#endif


/* Devfs daemon file operations */
@@ -791,46 +784,87 @@


/**
- * search_for_entry_in_dir - Search for a devfs entry inside another devfs entry.
- * @parent: The parent devfs entry.
- * @name: The name of the 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) );
+ }
+#ifdef CONFIG_DEVFS_DEBUG
+ spin_lock (&stat_lock);
+ --stat_num_entries;
+ stat_num_bytes -= sizeof *de + de->namelen;
+ if ( S_ISLNK (de->mode) ) stat_num_bytes -= de->u.symlink.length + 1;
+ spin_unlock (&stat_lock);
+#endif
+ kfree (de);
+} /* End Function devfs_put */
+
+/**
+ * _devfs_search_dir - Search for a devfs entry in a directory.
+ * @dir: The directory to search.
+ * @name: The name of the entry to search for.
* @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.
+ * Search for a devfs entry in a directory and returns a pointer to the entry
+ * on success, else %NULL. The directory 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 *dir,
+ const char *name,
+ unsigned int namelen)
{
- struct devfs_entry *curr, *retval;
+ struct devfs_entry *curr;

- if ( !S_ISDIR (parent->mode) )
+ if ( !S_ISDIR (dir->mode) )
{
printk ("%s: entry is not a directory\n", DEVFS_NAME);
return NULL;
}
- for (curr = parent->u.dir.first; curr != NULL; curr = curr->next)
+ for (curr = dir->u.dir.first; curr != NULL; curr = curr->next)
{
if (curr->namelen != namelen) continue;
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 */
+
+
+/**
+ * _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 *create_entry (struct devfs_entry *parent,
- const char *name,unsigned int namelen)
+static struct devfs_entry *_devfs_alloc_entry (const char *name,
+ unsigned int namelen,
+ umode_t mode)
{
struct devfs_entry *new;
static unsigned long inode_counter = FIRST_INODE;
@@ -839,168 +873,266 @@
if ( name && (namelen < 1) ) namelen = strlen (name);
if ( ( new = kmalloc (sizeof *new + namelen, GFP_KERNEL) ) == NULL )
return NULL;
- /* 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);
+ new->mode = mode;
+ if ( S_ISDIR (mode) ) rwlock_init (&new->u.dir.lock);
+ 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;
+#ifdef CONFIG_DEVFS_DEBUG
+ spin_lock (&stat_lock);
+ ++stat_num_entries;
+ stat_num_bytes += sizeof *new + namelen;
+ spin_unlock (&stat_lock);
+#endif
return new;
-} /* End Function create_entry */
+} /* End Function _devfs_alloc_entry */
+
+
+/**
+ * _devfs_append_entry - Append a devfs entry to a directory's child list.
+ * @dir: The directory to add to.
+ * @de: The devfs entry to append.
+ * @removable: If TRUE, increment the count of removable devices for %dir.
+ *
+ * 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.
+ * On failure, an implicit devfs_put() is performed on %de.
+ */

-static void update_devfs_inode_from_entry (struct devfs_entry *de)
+static int _devfs_append_entry (struct devfs_entry *dir,struct devfs_entry *de,
+ int removable)
{
- if (de == NULL) return;
- if ( S_ISDIR (de->mode) )
- {
- de->inode.mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO;
- de->inode.uid = 0;
- de->inode.gid = 0;
- }
- else if ( S_ISLNK (de->mode) )
- {
- de->inode.mode = S_IFLNK | S_IRUGO | S_IXUGO;
- de->inode.uid = 0;
- de->inode.gid = 0;
- }
- else if ( S_ISFIFO (de->mode) )
+ int retval;
+ struct devfs_entry *old;
+
+ if (!de || !dir) return 0;
+ if ( !S_ISDIR (dir->mode) )
{
- de->inode.mode = de->mode;
- de->inode.uid = de->u.fifo.uid;
- de->inode.gid = de->u.fifo.gid;
+ 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
{
- if (de->u.fcb.auto_owner)
- de->inode.mode = (de->mode & ~S_IALLUGO) | S_IRUGO | S_IWUGO;
- else de->inode.mode = de->mode;
- de->inode.uid = de->u.fcb.default_uid;
- de->inode.gid = de->u.fcb.default_gid;
+ 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;
+ if (removable) ++dir->u.dir.num_removable;
+ retval = 0;
+ }
+ else retval = -EEXIST;
}
-} /* End Function update_devfs_inode_from_entry */
+ write_unlock (&dir->u.dir.lock);
+ if (retval) devfs_put (de);
+ return retval;
+} /* End Function _devfs_append_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;
- /* Force an inode update, because lookup() is never done for the root */
- update_devfs_inode_from_entry (root_entry);
- root_entry->registered = TRUE;
+ if (root_entry) return root_entry;
+ if ( ( new = _devfs_alloc_entry (NULL, 0,
+ S_IFDIR | S_IWUSR | S_IRUGO | S_IXUGO) )
+ == NULL ) return NULL;
+ 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, S_IFCHR |S_IRUSR |S_IWUSR) )
+ == 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);
- new->mode = S_IFCHR | S_IRUSR | S_IWUSR;
- new->u.fcb.default_uid = 0;
- new->u.fcb.default_gid = 0;
new->u.fcb.ops = &devfsd_fops;
- new->registered = TRUE;
+ _devfs_append_entry (root_entry, new, FALSE);
+#ifdef CONFIG_DEVFS_DEBUG
+ if ( ( new = _devfs_alloc_entry (".stat", 0, S_IFCHR | S_IRUGO | S_IWUGO) )
+ == 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);
+ new->u.fcb.ops = &stat_fops;
+ _devfs_append_entry (root_entry, new, FALSE);
+#endif
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.
+ * _devfs_descend - Descend down a tree using the next component name.
+ * @dir: The directory to search.
+ * @name: The component name to search for.
+ * @namelen: The length of %name.
+ * @next_pos: The position of the next component (next '/').
*
- * If the entry is created, then it will be in the unregistered state.
- * Returns a pointer to the entry on success, else %NULL.
+ * Descend into a directory, searching for a component. This function forms
+ * the core of a tree-walking algorithm. The directory will be locked.
+ * The devfs entry corresponding to the component is returned. If there is
+ * no matching entry, %NULL is returned.
+ * An implicit devfs_get() is performed on the returned entry.
*/

-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 = 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)
- {
- /* Going up */
- dir = dir->parent;
- if (dir == NULL) return NULL; /* Cannot escape from devfs */
- subname += 3;
- continue;
+ /* 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)
+ {
+ if ( ( de = _devfs_descend (dir, name, namelen, &next_pos) ) == NULL )
+ {
+ if ( ( de = _devfs_alloc_entry (name, next_pos,
+ S_IFDIR |S_IWUSR|S_IRUGO|S_IXUGO) )
+ == NULL )
+ {
+ devfs_put (dir);
+ return NULL;
+ }
+ if ( _devfs_append_entry (dir, de, FALSE) )
+ {
+ devfs_put (dir);
+ 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, umode_t mode)
+{
+ 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,mode) )
+ == 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 */


/**
@@ -1020,20 +1152,29 @@
{
struct devfs_entry *entry, *de;

+ devfs_get (dir);
if (dir == NULL) return NULL;
if ( !S_ISDIR (dir->mode) )
{
printk ("%s: find_by_dev(): not a directory\n", DEVFS_NAME);
+ devfs_put (dir);
return NULL;
}
/* First search files in this directory */
+ read_lock (&dir->u.dir.lock);
for (entry = dir->u.dir.first; entry != NULL; entry = entry->next)
{
if ( !S_ISCHR (entry->mode) && !S_ISBLK (entry->mode) ) continue;
if ( S_ISCHR (entry->mode) && (type != DEVFS_SPECIAL_CHR) ) continue;
if ( S_ISBLK (entry->mode) && (type != DEVFS_SPECIAL_BLK) ) continue;
if ( (entry->u.fcb.u.device.major == major) &&
- (entry->u.fcb.u.device.minor == minor) ) return entry;
+ (entry->u.fcb.u.device.minor == minor) )
+ {
+ devfs_get (entry);
+ read_unlock (&dir->u.dir.lock);
+ devfs_put (dir);
+ return entry;
+ }
/* Not found: try the next one */
}
/* Now recursively search the subdirectories: this is a stack chomper */
@@ -1041,8 +1182,15 @@
{
if ( !S_ISDIR (entry->mode) ) continue;
de = find_by_dev (entry, major, minor, type);
- if (de) return de;
+ if (de)
+ {
+ read_unlock (&dir->u.dir.lock);
+ devfs_put (dir);
+ return de;
+ }
}
+ read_unlock (&dir->u.dir.lock);
+ devfs_put (dir);
return NULL;
} /* End Function find_by_dev */

@@ -1063,7 +1211,6 @@
* %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 +1242,7 @@
++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 */
@@ -1106,42 +1250,34 @@
return find_by_dev (root_entry, major, minor, type);
} /* End Function find_entry */

-static struct devfs_entry *get_devfs_entry_from_vfs_inode (struct inode *inode,
- int do_check)
+static struct devfs_entry *get_devfs_entry_from_vfs_inode (struct inode *inode)
{
- struct devfs_entry *de;
-
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;
- return de;
+ return inode->u.generic_ip;
} /* End Function get_devfs_entry_from_vfs_inode */


/**
- * free_dentries - Free the dentries for a device entry and invalidate inodes.
+ * free_dentry - Free the dentry for a device entry and invalidate inode.
* @de: The entry.
+ *
+ * This must only be called after the entry has been unhooked from it's
+ * parent directory.
*/

-static void free_dentries (struct devfs_entry *de)
+static void free_dentry (struct devfs_entry *de)
{
- struct dentry *dentry;
+ struct dentry *dentry = de->inode.dentry;

+ if (!dentry) return;
spin_lock (&dcache_lock);
- dentry = de->inode.dentry;
- if (dentry != NULL)
- {
- dget_locked (dentry);
- de->inode.dentry = NULL;
- spin_unlock (&dcache_lock);
- /* Forcefully remove the inode */
- if (dentry->d_inode != NULL) dentry->d_inode->i_nlink = 0;
- d_drop (dentry);
- dput (dentry);
- }
- else spin_unlock (&dcache_lock);
-} /* End Function free_dentries */
+ dget_locked (dentry);
+ spin_unlock (&dcache_lock);
+ /* Forcefully remove the inode */
+ if (dentry->d_inode != NULL) dentry->d_inode->i_nlink = 0;
+ d_drop (dentry);
+ dput (dentry);
+} /* End Function free_dentry */


/**
@@ -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;

@@ -1332,146 +1494,125 @@
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, mode) ) == 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) )
{
de->u.fcb.u.device.major = major;
de->u.fcb.u.device.minor = minor;
de->u.fcb.autogen = (devnum == NODEV) ? FALSE : TRUE;
}
- else if ( S_ISREG (mode) ) de->u.fcb.u.file.size = 0;
- else
+ else if ( !S_ISREG (mode) )
{
- 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);
return (NULL);
}
de->info = info;
- de->mode = mode;
if (flags & DEVFS_FL_CURRENT_OWNER)
{
- de->u.fcb.default_uid = current->uid;
- de->u.fcb.default_gid = current->gid;
+ de->inode.uid = current->uid;
+ de->inode.gid = current->gid;
}
else
{
- de->u.fcb.default_uid = 0;
- de->u.fcb.default_gid = 0;
+ de->inode.uid = 0;
+ de->inode.gid = 0;
}
de->u.fcb.ops = ops;
de->u.fcb.auto_owner = (flags & DEVFS_FL_AUTO_OWNER) ? TRUE : FALSE;
de->u.fcb.aopen_notify = (flags & DEVFS_FL_AOPEN_NOTIFY) ? TRUE : FALSE;
- if (flags & DEVFS_FL_REMOVABLE)
+ de->hide = (flags & DEVFS_FL_HIDE) ? TRUE : FALSE;
+ if (flags & DEVFS_FL_REMOVABLE) de->u.fcb.removable = TRUE;
+ if ( _devfs_append_entry (dir, de, de->u.fcb.removable) )
{
- de->u.fcb.removable = TRUE;
- ++de->parent->u.dir.num_removable;
+ printk ("%s: devfs_register(%s): could not append to parent\n",
+ DEVFS_NAME, name);
+ devfs_put (dir);
+ if (devnum != NODEV) devfs_dealloc_devnum (devtype, devnum);
+ return NULL;
}
- 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;
+#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> */
+ if ( ( S_ISREG (de->mode) || S_ISCHR (de->mode) || S_ISBLK (de->mode) ) &&
+ de->u.fcb.removable )
+ --parent->u.dir.num_removable;
+ 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_dentry (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 +1625,22 @@

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;
+ int err;
unsigned int linklength;
char *newlink;
struct devfs_entry *de;
@@ -1522,28 +1665,31 @@
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, S_IFLNK | S_IRUGO | S_IXUGO) )
+ == 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 ( ( err = _devfs_append_entry (dir, de, FALSE) ) != 0 )
+ {
+ printk ("%s: devfs_do_symlink(%s): could not append to parent, err: %d\n",
+ DEVFS_NAME, name, err);
+ devfs_put (dir);
+ return err;
+ }
+ devfs_put (dir);
+#ifdef CONFIG_DEVFS_DEBUG
+ spin_lock (&stat_lock);
+ stat_num_bytes += linklength + 1;
+ spin_unlock (&stat_lock);
+#endif
if (handle != NULL) *handle = de;
return 0;
} /* End Function devfs_do_symlink */
@@ -1593,7 +1739,6 @@

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 +1746,27 @@
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,
+ S_IFDIR | S_IWUSR | S_IRUGO | S_IXUGO) )
+ == 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->info = info;
+ if ( _devfs_append_entry (dir, de, FALSE) )
{
- 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 (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 */

@@ -1660,8 +1796,8 @@

if ( (name != NULL) && (name[0] == '\0') ) name = NULL;
de = find_entry (dir, name, 0, major, minor, type, traverse_symlinks);
- if (de == NULL) return NULL;
- if (!de->registered) return NULL;
+ devfs_put (de); /* FIXME: in 2.5 consider dropping this and require a
+ call to devfs_put() */
return de;
} /* End Function devfs_find_handle */

@@ -1679,7 +1815,6 @@
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 +1838,6 @@
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",
@@ -1714,16 +1848,6 @@
{
de->u.fcb.auto_owner = (flags & DEVFS_FL_AUTO_OWNER) ? TRUE : FALSE;
de->u.fcb.aopen_notify = (flags & DEVFS_FL_AOPEN_NOTIFY) ? TRUE:FALSE;
- if ( de->u.fcb.removable && !(flags & DEVFS_FL_REMOVABLE) )
- {
- de->u.fcb.removable = FALSE;
- --de->parent->u.dir.num_removable;
- }
- else if ( !de->u.fcb.removable && (flags & DEVFS_FL_REMOVABLE) )
- {
- de->u.fcb.removable = TRUE;
- ++de->parent->u.dir.num_removable;
- }
}
return 0;
} /* End Function devfs_set_flags */
@@ -1742,7 +1866,6 @@
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;
@@ -1762,7 +1885,7 @@
{
if (!inode || !inode->i_sb) return NULL;
if (inode->i_sb->s_magic != DEVFS_SUPER_MAGIC) return NULL;
- return get_devfs_entry_from_vfs_inode (inode, TRUE);
+ return get_devfs_entry_from_vfs_inode (inode);
} /* End Function devfs_get_handle_from_inode */


@@ -1808,7 +1931,6 @@
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 +1948,6 @@
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 +1967,6 @@
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 +1981,6 @@
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 +1995,6 @@
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 +2009,6 @@
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 +2024,6 @@
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 +2077,6 @@
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 +2174,7 @@
{"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 +2245,13 @@


/**
- * 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 +2322,6 @@
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 +2344,6 @@

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);
@@ -2258,7 +2372,7 @@
struct inode *inode = dentry->d_inode;
struct fs_info *fs_info = inode->i_sb->u.generic_sbp;

- de = get_devfs_entry_from_vfs_inode (inode, TRUE);
+ de = get_devfs_entry_from_vfs_inode (inode);
if (de == NULL) return -ENODEV;
retval = inode_change_ok (inode, iattr);
if (retval != 0) return retval;
@@ -2276,15 +2390,19 @@
#endif
/* Inode is not on hash chains, thus must save permissions here rather
than in a write_inode() method */
- de->inode.mode = inode->i_mode;
- de->inode.uid = inode->i_uid;
- de->inode.gid = inode->i_gid;
+ if ( ( !S_ISREG (inode->i_mode) && !S_ISCHR (inode->i_mode) &&
+ !S_ISBLK (inode->i_mode) ) || !de->u.fcb.auto_owner )
+ {
+ de->mode = inode->i_mode;
+ de->inode.uid = inode->i_uid;
+ de->inode.gid = inode->i_gid;
+ }
de->inode.atime = inode->i_atime;
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 +2417,10 @@
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 =
{
@@ -2319,32 +2436,37 @@
* @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,
struct devfs_entry *de,
struct dentry *dentry)
{
+ int is_fcb = FALSE;
struct inode *inode;

- if (de->inode.dentry != NULL)
- {
- printk ("%s: get_vfs_inode(%u): old de->inode.dentry: %p \"%s\" new dentry: %p \"%s\"\n",
- DEVFS_NAME, de->inode.ino,
- de->inode.dentry, de->inode.dentry->d_name.name,
- dentry, dentry->d_name.name);
- printk (" old inode: %p\n", de->inode.dentry->d_inode);
- return NULL;
- }
+ if (de->prev == de) return NULL; /* Quick check to see if unhooked */
if ( ( inode = new_inode (sb) ) == NULL )
{
printk ("%s: get_vfs_inode(%s): new_inode() failed, de: %p\n",
DEVFS_NAME, de->name, de);
return NULL;
}
- de->inode.dentry = dentry;
- inode->u.generic_ip = de;
+ if (de->parent)
+ {
+ read_lock (&de->parent->u.dir.lock);
+ if (de->prev != de) de->inode.dentry = dentry; /* Not unhooked */
+ read_unlock (&de->parent->u.dir.lock);
+ }
+ else de->inode.dentry = dentry; /* Root: no locking needed */
+ if (de->inode.dentry != dentry)
+ { /* Must have been unhooked */
+ iput (inode);
+ return NULL;
+ }
+ inode->u.generic_ip = devfs_get (de);
inode->i_ino = de->inode.ino;
#ifdef CONFIG_DEVFS_DEBUG
if (devfs_debug & DEBUG_I_GET)
@@ -2356,37 +2478,45 @@
inode->i_op = &devfs_iops;
inode->i_fop = &devfs_fops;
inode->i_rdev = NODEV;
- if ( S_ISCHR (de->inode.mode) )
+ if ( S_ISCHR (de->mode) )
{
inode->i_rdev = MKDEV (de->u.fcb.u.device.major,
de->u.fcb.u.device.minor);
- inode->i_cdev = cdget (kdev_t_to_nr(inode->i_rdev));
+ inode->i_cdev = cdget ( kdev_t_to_nr (inode->i_rdev) );
+ is_fcb = TRUE;
}
- else if ( S_ISBLK (de->inode.mode) )
+ else if ( S_ISBLK (de->mode) )
{
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;
}
else printk ("%s: get_vfs_inode(%d): no block device from bdget()\n",
DEVFS_NAME, (int) inode->i_ino);
+ is_fcb = TRUE;
+ }
+ else if ( S_ISFIFO (de->mode) ) inode->i_fop = &def_fifo_fops;
+ else if ( S_ISREG (de->mode) )
+ {
+ inode->i_size = de->u.fcb.u.file.size;
+ is_fcb = TRUE;
}
- else if ( S_ISFIFO (de->inode.mode) ) inode->i_fop = &def_fifo_fops;
- else if ( S_ISREG (de->inode.mode) ) inode->i_size = de->u.fcb.u.file.size;
- else if ( S_ISDIR (de->inode.mode) )
+ else if ( S_ISDIR (de->mode) )
{
inode->i_op = &devfs_dir_iops;
inode->i_fop = &devfs_dir_fops;
}
- else if ( S_ISLNK (de->inode.mode) )
+ else if ( S_ISLNK (de->mode) )
{
inode->i_op = &devfs_symlink_iops;
inode->i_size = de->u.symlink.length;
}
- inode->i_mode = de->inode.mode;
+ if (is_fcb && de->u.fcb.auto_owner)
+ inode->i_mode = (de->mode & S_IFMT) | S_IRUGO | S_IWUGO;
+ else inode->i_mode = de->mode;
inode->i_uid = de->inode.uid;
inode->i_gid = de->inode.gid;
inode->i_atime = de->inode.atime;
@@ -2409,11 +2539,11 @@
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;
- parent = get_devfs_entry_from_vfs_inode (file->f_dentry->d_inode, TRUE);
+ parent = get_devfs_entry_from_vfs_inode (file->f_dentry->d_inode);
if ( (long) file->f_pos < 0 ) return -EINVAL;
#ifdef CONFIG_DEVFS_DEBUG
if (devfs_debug & DEBUG_F_READDIR)
@@ -2441,19 +2571,32 @@
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 +2610,9 @@
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;
+ de = get_devfs_entry_from_vfs_inode (inode);
+ 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 +2620,7 @@
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
@@ -2491,39 +2629,33 @@
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)
{
- /* Change the ownership/protection */
- de->inode.mode = (de->inode.mode & ~S_IALLUGO) |(de->mode & S_IRWXUGO);
- de->inode.uid = current->euid;
- de->inode.gid = current->egid;
- inode->i_mode = de->inode.mode;
- inode->i_uid = de->inode.uid;
- inode->i_gid = de->inode.gid;
+ /* Change the ownership/protection to what driver specified */
+ inode->i_mode = de->mode;
+ inode->i_uid = current->euid;
+ inode->i_gid = current->egid;
}
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,
};


@@ -2556,16 +2688,18 @@
{
struct devfs_entry *de;

- lock_kernel ();
- de = get_devfs_entry_from_vfs_inode (inode, FALSE);
+ de = get_devfs_entry_from_vfs_inode (inode);
#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 && (de->inode.dentry != dentry) )
+ OOPS ("%s: d_iput(%s): de: %p dentry: %p de->dentry: %p\n",
+ DEVFS_NAME, de->name, de, dentry, de->inode.dentry);
+ de->inode.dentry = NULL;
iput (inode);
+ devfs_put (de);
} /* End Function devfs_d_iput */

static int devfs_d_delete (struct dentry *dentry);
@@ -2610,7 +2744,7 @@
return 1;
}
fs_info = inode->i_sb->u.generic_sbp;
- de = get_devfs_entry_from_vfs_inode (inode, TRUE);
+ de = get_devfs_entry_from_vfs_inode (inode);
#ifdef CONFIG_DEVFS_DEBUG
if (devfs_debug & DEBUG_D_DELETE)
printk ("%s: d_delete(): dentry: %p inode: %p devfs_entry: %p\n",
@@ -2622,14 +2756,11 @@
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;
- de->inode.uid = de->u.fcb.default_uid;
- de->inode.gid = de->u.fcb.default_gid;
- inode->i_mode = de->inode.mode;
+ inode->i_mode = (de->mode & S_IFMT) | S_IRUGO | S_IWUGO;
inode->i_uid = de->inode.uid;
inode->i_gid = de->inode.gid;
return 0;
@@ -2637,59 +2768,44 @@

static int devfs_d_revalidate_wait (struct dentry *dentry, int flags)
{
- devfs_handle_t de = dentry->d_fsdata;
- struct inode *dir;
- struct fs_info *fs_info;
+ struct inode *dir = dentry->d_parent->d_inode;
+ struct fs_info *fs_info = dir->i_sb->u.generic_sbp;

- lock_kernel ();
- dir = dentry->d_parent->d_inode;
- fs_info = dir->i_sb->u.generic_sbp;
- if (!de || de->registered)
+ if ( !dentry->d_inode && is_devfsd_or_child (fs_info) )
{
- if ( !dentry->d_inode && is_devfsd_or_child (fs_info) )
- {
- struct inode *inode;
+ devfs_handle_t de;
+ devfs_handle_t parent = get_devfs_entry_from_vfs_inode (dir);
+ struct inode *inode;

#ifdef CONFIG_DEVFS_DEBUG
- char txt[STRING_LENGTH];
-
- memset (txt, 0, STRING_LENGTH);
- memcpy (txt, dentry->d_name.name,
- (dentry->d_name.len >= STRING_LENGTH) ?
- (STRING_LENGTH - 1) : dentry->d_name.len);
- if (devfs_debug & DEBUG_I_LOOKUP)
- printk ("%s: d_revalidate(): dentry: %p name: \"%s\" by: \"%s\"\n",
- DEVFS_NAME, dentry, txt, current->comm);
-#endif
- if (de == NULL)
- {
- devfs_handle_t parent;
+ char txt[STRING_LENGTH];

- 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);
- }
- if (de == NULL) goto out;
- /* 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);
- 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;
-#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);
+ memset (txt, 0, STRING_LENGTH);
+ memcpy (txt, dentry->d_name.name,
+ (dentry->d_name.len >= STRING_LENGTH) ?
+ (STRING_LENGTH - 1) : dentry->d_name.len);
+ if (devfs_debug & DEBUG_I_LOOKUP)
+ printk ("%s: d_revalidate(): dentry: %p name: \"%s\" by: \"%s\"\n",
+ DEVFS_NAME, dentry, txt, current->comm);
+#endif
+ read_lock (&parent->u.dir.lock);
+ de = _devfs_search_dir (parent, dentry->d_name.name,
+ dentry->d_name.len);
+ read_lock (&parent->u.dir.lock);
+ if (de == NULL) return 1;
+ /* Create an inode, now that the driver information is available */
+ 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;
- }
+ d_instantiate (dentry, inode);
+ 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 */

@@ -2712,27 +2828,26 @@
(STRING_LENGTH - 1) : dentry->d_name.len);
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);
+ parent = get_devfs_entry_from_vfs_inode (dir);
#ifdef CONFIG_DEVFS_DEBUG
if (devfs_debug & DEBUG_I_LOOKUP)
printk ("%s: lookup(%s): dentry: %p parent: %p by: \"%s\"\n",
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
@@ -2747,21 +2862,20 @@
}
/* 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
revalidation */
up (&dir->i_sem);
- devfs_d_revalidate_wait (dentry, 0); /* I might have to wait too */
+ devfs_d_revalidate_wait (dentry, 0); /* I might have to wait too */
down (&dir->i_sem); /* Grab it again because them's the rules */
/* 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 */
}
@@ -2771,29 +2885,29 @@
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);
- 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",
DEVFS_NAME, de->inode.ino, inode, de);
#endif
d_instantiate (dentry, inode);
- /* Unlock directory semaphore, which will release any waiters. They will
- get the hashed dentry, and may be forced to wait for revalidation */
- up (&dir->i_sem);
if (dentry->d_op == &devfs_wait_dops)
- devfs_d_revalidate_wait (dentry, 0); /* I might have to wait too */
- down (&dir->i_sem); /* Grab it again because them's the rules */
+ { /* Unlock directory semaphore, which will release any waiters. They
+ will get the hashed dentry, and may be forced to wait for
+ revalidation */
+ up (&dir->i_sem);
+ devfs_d_revalidate_wait (dentry, 0); /* I might have to wait too */
+ down (&dir->i_sem); /* Grab it again because them's the rules */
+ }
return NULL;
} /* End Function devfs_lookup */

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

@@ -2809,20 +2923,17 @@
}
#endif

- de = get_devfs_entry_from_vfs_inode (dentry->d_inode, TRUE);
+ de = get_devfs_entry_from_vfs_inode (inode);
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);
- }
- free_dentries (de);
+ 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_dentry (de);
+ devfs_put (de);
return 0;
} /* End Function devfs_unlink */

@@ -2836,7 +2947,7 @@

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);
+ parent = get_devfs_entry_from_vfs_inode (dir);
if (parent == NULL) return -ENOENT;
err = devfs_do_symlink (parent, dentry->d_name.name, DEVFS_FL_NONE,
symname, &de, NULL);
@@ -2846,7 +2957,9 @@
DEVFS_NAME, err);
#endif
if (err < 0) return err;
- de->inode.mode = de->mode;
+ de->vfs_created = TRUE;
+ 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;
@@ -2857,50 +2970,32 @@
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;
+ int err;
struct fs_info *fs_info;
struct devfs_entry *parent, *de;
struct inode *inode;

- mode = (mode & ~S_IFMT) | S_IFDIR;
+ mode = (mode & ~S_IFMT) | S_IFDIR; /* VFS doesn't pass S_IFMT part */
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);
+ parent = get_devfs_entry_from_vfs_inode (dir);
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: mkdir(): existing 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 = _devfs_alloc_entry (dentry->d_name.name, dentry->d_name.len, mode);
+ if (!de) return -ENOMEM;
+ de->vfs_created = TRUE;
+ if ( ( err = _devfs_append_entry (parent, de, FALSE) ) != 0 ) return err;
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
@@ -2909,44 +3004,46 @@
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;
fs_info = dir->i_sb->u.generic_sbp;
- de = get_devfs_entry_from_vfs_inode (inode, TRUE);
+ de = get_devfs_entry_from_vfs_inode (inode);
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;
- free_dentries (de);
+ 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_dentry (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;
+ int err;
struct fs_info *fs_info;
struct devfs_entry *parent, *de;
struct inode *inode;
@@ -2963,46 +3060,23 @@
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);
+ parent = get_devfs_entry_from_vfs_inode (dir);
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->mode = mode;
+ de = _devfs_alloc_entry (dentry->d_name.name, dentry->d_name.len, mode);
+ if (!de) return -ENOMEM;
+ de->vfs_created = TRUE;
if ( S_ISBLK (mode) || S_ISCHR (mode) )
{
de->u.fcb.u.device.major = MAJOR (rdev);
de->u.fcb.u.device.minor = MINOR (rdev);
- de->u.fcb.default_uid = current->euid;
- de->u.fcb.default_gid = current->egid;
- de->u.fcb.ops = NULL;
- de->u.fcb.auto_owner = FALSE;
- de->u.fcb.aopen_notify = FALSE;
- de->u.fcb.open = FALSE;
- }
- else if ( S_ISFIFO (mode) )
- {
- de->u.fifo.uid = current->euid;
- de->u.fifo.gid = current->egid;
}
- de->hide = FALSE;
- de->inode.mode = mode;
+ if ( ( err = _devfs_append_entry (parent, de, FALSE) ) != 0 ) return err;
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 +3085,8 @@
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 */

@@ -3021,12 +3095,9 @@
int err;
struct devfs_entry *de;

- de = get_devfs_entry_from_vfs_inode (dentry->d_inode, TRUE);
+ de = get_devfs_entry_from_vfs_inode (dentry->d_inode);
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 +3105,10 @@
{
int err;
struct devfs_entry *de;
- char *copy;

- de = get_devfs_entry_from_vfs_inode (dentry->d_inode, TRUE);
+ de = get_devfs_entry_from_vfs_inode (dentry->d_inode);
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 +3140,7 @@
{
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 +3155,7 @@
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 +3238,7 @@
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;
@@ -3306,6 +3363,25 @@
wake_up (&fs_info->revalidate_wait_queue);
return 0;
} /* End Function devfsd_close */
+
+#ifdef CONFIG_DEVFS_DEBUG
+static ssize_t stat_read (struct file *file, char *buf, size_t len,
+ loff_t *ppos)
+{
+ ssize_t num;
+ char txt[80];
+
+ num = sprintf (txt, "Number of entries: %u number of bytes: %u\n",
+ stat_num_entries, stat_num_bytes) + 1;
+ /* Can't seek (pread) on this device */
+ if (ppos != &file->f_pos) return -ESPIPE;
+ if (*ppos >= num) return 0;
+ if (*ppos + len > num) len = num - *ppos;
+ if ( copy_to_user (buf, txt + *ppos, len) ) return -EFAULT;
+ *ppos += len;
+ return len;
+} /* End Function stat_read */
+#endif


static int __init init_devfs_fs (void)
-
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