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authorAnton Altaparmakov <aia21@cantab.net>2006-01-19 11:39:33 -0500
committerAnton Altaparmakov <aia21@cantab.net>2006-01-19 11:39:33 -0500
commit944d79559d154c12becde0dab327016cf438f46c (patch)
tree50c101806f4d3b6585222dda060559eb4f3e005a /Documentation/filesystems
parentd087e4bdd24ebe3ae3d0b265b6573ec901af4b4b (diff)
parent0f36b018b2e314d45af86449f1a97facb1fbe300 (diff)
Merge branch 'master' of /usr/src/ntfs-2.6/
Diffstat (limited to 'Documentation/filesystems')
-rw-r--r--Documentation/filesystems/00-INDEX8
-rw-r--r--Documentation/filesystems/configfs/configfs.txt434
-rw-r--r--Documentation/filesystems/configfs/configfs_example.c474
-rw-r--r--Documentation/filesystems/dlmfs.txt130
-rw-r--r--Documentation/filesystems/ext3.txt181
-rw-r--r--Documentation/filesystems/fuse.txt63
-rw-r--r--Documentation/filesystems/ocfs2.txt55
-rw-r--r--Documentation/filesystems/proc.txt19
-rw-r--r--Documentation/filesystems/ramfs-rootfs-initramfs.txt72
-rw-r--r--Documentation/filesystems/relayfs.txt126
-rw-r--r--Documentation/filesystems/spufs.txt521
-rw-r--r--Documentation/filesystems/sysfs-pci.txt21
-rw-r--r--Documentation/filesystems/tmpfs.txt12
-rw-r--r--Documentation/filesystems/vfs.txt5
14 files changed, 1998 insertions, 123 deletions
diff --git a/Documentation/filesystems/00-INDEX b/Documentation/filesystems/00-INDEX
index bcfbab899b37..74052d22d868 100644
--- a/Documentation/filesystems/00-INDEX
+++ b/Documentation/filesystems/00-INDEX
@@ -12,14 +12,16 @@ cifs.txt
12 - description of the CIFS filesystem 12 - description of the CIFS filesystem
13coda.txt 13coda.txt
14 - description of the CODA filesystem. 14 - description of the CODA filesystem.
15configfs/
16 - directory containing configfs documentation and example code.
15cramfs.txt 17cramfs.txt
16 - info on the cram filesystem for small storage (ROMs etc) 18 - info on the cram filesystem for small storage (ROMs etc)
17devfs/ 19devfs/
18 - directory containing devfs documentation. 20 - directory containing devfs documentation.
21dlmfs.txt
22 - info on the userspace interface to the OCFS2 DLM.
19ext2.txt 23ext2.txt
20 - info, mount options and specifications for the Ext2 filesystem. 24 - info, mount options and specifications for the Ext2 filesystem.
21fat_cvf.txt
22 - info on the Compressed Volume Files extension to the FAT filesystem
23hpfs.txt 25hpfs.txt
24 - info and mount options for the OS/2 HPFS. 26 - info and mount options for the OS/2 HPFS.
25isofs.txt 27isofs.txt
@@ -32,6 +34,8 @@ ntfs.txt
32 - info and mount options for the NTFS filesystem (Windows NT). 34 - info and mount options for the NTFS filesystem (Windows NT).
33proc.txt 35proc.txt
34 - info on Linux's /proc filesystem. 36 - info on Linux's /proc filesystem.
37ocfs2.txt
38 - info and mount options for the OCFS2 clustered filesystem.
35romfs.txt 39romfs.txt
36 - Description of the ROMFS filesystem. 40 - Description of the ROMFS filesystem.
37smbfs.txt 41smbfs.txt
diff --git a/Documentation/filesystems/configfs/configfs.txt b/Documentation/filesystems/configfs/configfs.txt
new file mode 100644
index 000000000000..c4ff96b7c4e0
--- /dev/null
+++ b/Documentation/filesystems/configfs/configfs.txt
@@ -0,0 +1,434 @@
1
2configfs - Userspace-driven kernel object configuation.
3
4Joel Becker <joel.becker@oracle.com>
5
6Updated: 31 March 2005
7
8Copyright (c) 2005 Oracle Corporation,
9 Joel Becker <joel.becker@oracle.com>
10
11
12[What is configfs?]
13
14configfs is a ram-based filesystem that provides the converse of
15sysfs's functionality. Where sysfs is a filesystem-based view of
16kernel objects, configfs is a filesystem-based manager of kernel
17objects, or config_items.
18
19With sysfs, an object is created in kernel (for example, when a device
20is discovered) and it is registered with sysfs. Its attributes then
21appear in sysfs, allowing userspace to read the attributes via
22readdir(3)/read(2). It may allow some attributes to be modified via
23write(2). The important point is that the object is created and
24destroyed in kernel, the kernel controls the lifecycle of the sysfs
25representation, and sysfs is merely a window on all this.
26
27A configfs config_item is created via an explicit userspace operation:
28mkdir(2). It is destroyed via rmdir(2). The attributes appear at
29mkdir(2) time, and can be read or modified via read(2) and write(2).
30As with sysfs, readdir(3) queries the list of items and/or attributes.
31symlink(2) can be used to group items together. Unlike sysfs, the
32lifetime of the representation is completely driven by userspace. The
33kernel modules backing the items must respond to this.
34
35Both sysfs and configfs can and should exist together on the same
36system. One is not a replacement for the other.
37
38[Using configfs]
39
40configfs can be compiled as a module or into the kernel. You can access
41it by doing
42
43 mount -t configfs none /config
44
45The configfs tree will be empty unless client modules are also loaded.
46These are modules that register their item types with configfs as
47subsystems. Once a client subsystem is loaded, it will appear as a
48subdirectory (or more than one) under /config. Like sysfs, the
49configfs tree is always there, whether mounted on /config or not.
50
51An item is created via mkdir(2). The item's attributes will also
52appear at this time. readdir(3) can determine what the attributes are,
53read(2) can query their default values, and write(2) can store new
54values. Like sysfs, attributes should be ASCII text files, preferably
55with only one value per file. The same efficiency caveats from sysfs
56apply. Don't mix more than one attribute in one attribute file.
57
58Like sysfs, configfs expects write(2) to store the entire buffer at
59once. When writing to configfs attributes, userspace processes should
60first read the entire file, modify the portions they wish to change, and
61then write the entire buffer back. Attribute files have a maximum size
62of one page (PAGE_SIZE, 4096 on i386).
63
64When an item needs to be destroyed, remove it with rmdir(2). An
65item cannot be destroyed if any other item has a link to it (via
66symlink(2)). Links can be removed via unlink(2).
67
68[Configuring FakeNBD: an Example]
69
70Imagine there's a Network Block Device (NBD) driver that allows you to
71access remote block devices. Call it FakeNBD. FakeNBD uses configfs
72for its configuration. Obviously, there will be a nice program that
73sysadmins use to configure FakeNBD, but somehow that program has to tell
74the driver about it. Here's where configfs comes in.
75
76When the FakeNBD driver is loaded, it registers itself with configfs.
77readdir(3) sees this just fine:
78
79 # ls /config
80 fakenbd
81
82A fakenbd connection can be created with mkdir(2). The name is
83arbitrary, but likely the tool will make some use of the name. Perhaps
84it is a uuid or a disk name:
85
86 # mkdir /config/fakenbd/disk1
87 # ls /config/fakenbd/disk1
88 target device rw
89
90The target attribute contains the IP address of the server FakeNBD will
91connect to. The device attribute is the device on the server.
92Predictably, the rw attribute determines whether the connection is
93read-only or read-write.
94
95 # echo 10.0.0.1 > /config/fakenbd/disk1/target
96 # echo /dev/sda1 > /config/fakenbd/disk1/device
97 # echo 1 > /config/fakenbd/disk1/rw
98
99That's it. That's all there is. Now the device is configured, via the
100shell no less.
101
102[Coding With configfs]
103
104Every object in configfs is a config_item. A config_item reflects an
105object in the subsystem. It has attributes that match values on that
106object. configfs handles the filesystem representation of that object
107and its attributes, allowing the subsystem to ignore all but the
108basic show/store interaction.
109
110Items are created and destroyed inside a config_group. A group is a
111collection of items that share the same attributes and operations.
112Items are created by mkdir(2) and removed by rmdir(2), but configfs
113handles that. The group has a set of operations to perform these tasks
114
115A subsystem is the top level of a client module. During initialization,
116the client module registers the subsystem with configfs, the subsystem
117appears as a directory at the top of the configfs filesystem. A
118subsystem is also a config_group, and can do everything a config_group
119can.
120
121[struct config_item]
122
123 struct config_item {
124 char *ci_name;
125 char ci_namebuf[UOBJ_NAME_LEN];
126 struct kref ci_kref;
127 struct list_head ci_entry;
128 struct config_item *ci_parent;
129 struct config_group *ci_group;
130 struct config_item_type *ci_type;
131 struct dentry *ci_dentry;
132 };
133
134 void config_item_init(struct config_item *);
135 void config_item_init_type_name(struct config_item *,
136 const char *name,
137 struct config_item_type *type);
138 struct config_item *config_item_get(struct config_item *);
139 void config_item_put(struct config_item *);
140
141Generally, struct config_item is embedded in a container structure, a
142structure that actually represents what the subsystem is doing. The
143config_item portion of that structure is how the object interacts with
144configfs.
145
146Whether statically defined in a source file or created by a parent
147config_group, a config_item must have one of the _init() functions
148called on it. This initializes the reference count and sets up the
149appropriate fields.
150
151All users of a config_item should have a reference on it via
152config_item_get(), and drop the reference when they are done via
153config_item_put().
154
155By itself, a config_item cannot do much more than appear in configfs.
156Usually a subsystem wants the item to display and/or store attributes,
157among other things. For that, it needs a type.
158
159[struct config_item_type]
160
161 struct configfs_item_operations {
162 void (*release)(struct config_item *);
163 ssize_t (*show_attribute)(struct config_item *,
164 struct configfs_attribute *,
165 char *);
166 ssize_t (*store_attribute)(struct config_item *,
167 struct configfs_attribute *,
168 const char *, size_t);
169 int (*allow_link)(struct config_item *src,
170 struct config_item *target);
171 int (*drop_link)(struct config_item *src,
172 struct config_item *target);
173 };
174
175 struct config_item_type {
176 struct module *ct_owner;
177 struct configfs_item_operations *ct_item_ops;
178 struct configfs_group_operations *ct_group_ops;
179 struct configfs_attribute **ct_attrs;
180 };
181
182The most basic function of a config_item_type is to define what
183operations can be performed on a config_item. All items that have been
184allocated dynamically will need to provide the ct_item_ops->release()
185method. This method is called when the config_item's reference count
186reaches zero. Items that wish to display an attribute need to provide
187the ct_item_ops->show_attribute() method. Similarly, storing a new
188attribute value uses the store_attribute() method.
189
190[struct configfs_attribute]
191
192 struct configfs_attribute {
193 char *ca_name;
194 struct module *ca_owner;
195 mode_t ca_mode;
196 };
197
198When a config_item wants an attribute to appear as a file in the item's
199configfs directory, it must define a configfs_attribute describing it.
200It then adds the attribute to the NULL-terminated array
201config_item_type->ct_attrs. When the item appears in configfs, the
202attribute file will appear with the configfs_attribute->ca_name
203filename. configfs_attribute->ca_mode specifies the file permissions.
204
205If an attribute is readable and the config_item provides a
206ct_item_ops->show_attribute() method, that method will be called
207whenever userspace asks for a read(2) on the attribute. The converse
208will happen for write(2).
209
210[struct config_group]
211
212A config_item cannot live in a vaccum. The only way one can be created
213is via mkdir(2) on a config_group. This will trigger creation of a
214child item.
215
216 struct config_group {
217 struct config_item cg_item;
218 struct list_head cg_children;
219 struct configfs_subsystem *cg_subsys;
220 struct config_group **default_groups;
221 };
222
223 void config_group_init(struct config_group *group);
224 void config_group_init_type_name(struct config_group *group,
225 const char *name,
226 struct config_item_type *type);
227
228
229The config_group structure contains a config_item. Properly configuring
230that item means that a group can behave as an item in its own right.
231However, it can do more: it can create child items or groups. This is
232accomplished via the group operations specified on the group's
233config_item_type.
234
235 struct configfs_group_operations {
236 struct config_item *(*make_item)(struct config_group *group,
237 const char *name);
238 struct config_group *(*make_group)(struct config_group *group,
239 const char *name);
240 int (*commit_item)(struct config_item *item);
241 void (*drop_item)(struct config_group *group,
242 struct config_item *item);
243 };
244
245A group creates child items by providing the
246ct_group_ops->make_item() method. If provided, this method is called from mkdir(2) in the group's directory. The subsystem allocates a new
247config_item (or more likely, its container structure), initializes it,
248and returns it to configfs. Configfs will then populate the filesystem
249tree to reflect the new item.
250
251If the subsystem wants the child to be a group itself, the subsystem
252provides ct_group_ops->make_group(). Everything else behaves the same,
253using the group _init() functions on the group.
254
255Finally, when userspace calls rmdir(2) on the item or group,
256ct_group_ops->drop_item() is called. As a config_group is also a
257config_item, it is not necessary for a seperate drop_group() method.
258The subsystem must config_item_put() the reference that was initialized
259upon item allocation. If a subsystem has no work to do, it may omit
260the ct_group_ops->drop_item() method, and configfs will call
261config_item_put() on the item on behalf of the subsystem.
262
263IMPORTANT: drop_item() is void, and as such cannot fail. When rmdir(2)
264is called, configfs WILL remove the item from the filesystem tree
265(assuming that it has no children to keep it busy). The subsystem is
266responsible for responding to this. If the subsystem has references to
267the item in other threads, the memory is safe. It may take some time
268for the item to actually disappear from the subsystem's usage. But it
269is gone from configfs.
270
271A config_group cannot be removed while it still has child items. This
272is implemented in the configfs rmdir(2) code. ->drop_item() will not be
273called, as the item has not been dropped. rmdir(2) will fail, as the
274directory is not empty.
275
276[struct configfs_subsystem]
277
278A subsystem must register itself, ususally at module_init time. This
279tells configfs to make the subsystem appear in the file tree.
280
281 struct configfs_subsystem {
282 struct config_group su_group;
283 struct semaphore su_sem;
284 };
285
286 int configfs_register_subsystem(struct configfs_subsystem *subsys);
287 void configfs_unregister_subsystem(struct configfs_subsystem *subsys);
288
289 A subsystem consists of a toplevel config_group and a semaphore.
290The group is where child config_items are created. For a subsystem,
291this group is usually defined statically. Before calling
292configfs_register_subsystem(), the subsystem must have initialized the
293group via the usual group _init() functions, and it must also have
294initialized the semaphore.
295 When the register call returns, the subsystem is live, and it
296will be visible via configfs. At that point, mkdir(2) can be called and
297the subsystem must be ready for it.
298
299[An Example]
300
301The best example of these basic concepts is the simple_children
302subsystem/group and the simple_child item in configfs_example.c It
303shows a trivial object displaying and storing an attribute, and a simple
304group creating and destroying these children.
305
306[Hierarchy Navigation and the Subsystem Semaphore]
307
308There is an extra bonus that configfs provides. The config_groups and
309config_items are arranged in a hierarchy due to the fact that they
310appear in a filesystem. A subsystem is NEVER to touch the filesystem
311parts, but the subsystem might be interested in this hierarchy. For
312this reason, the hierarchy is mirrored via the config_group->cg_children
313and config_item->ci_parent structure members.
314
315A subsystem can navigate the cg_children list and the ci_parent pointer
316to see the tree created by the subsystem. This can race with configfs'
317management of the hierarchy, so configfs uses the subsystem semaphore to
318protect modifications. Whenever a subsystem wants to navigate the
319hierarchy, it must do so under the protection of the subsystem
320semaphore.
321
322A subsystem will be prevented from acquiring the semaphore while a newly
323allocated item has not been linked into this hierarchy. Similarly, it
324will not be able to acquire the semaphore while a dropping item has not
325yet been unlinked. This means that an item's ci_parent pointer will
326never be NULL while the item is in configfs, and that an item will only
327be in its parent's cg_children list for the same duration. This allows
328a subsystem to trust ci_parent and cg_children while they hold the
329semaphore.
330
331[Item Aggregation Via symlink(2)]
332
333configfs provides a simple group via the group->item parent/child
334relationship. Often, however, a larger environment requires aggregation
335outside of the parent/child connection. This is implemented via
336symlink(2).
337
338A config_item may provide the ct_item_ops->allow_link() and
339ct_item_ops->drop_link() methods. If the ->allow_link() method exists,
340symlink(2) may be called with the config_item as the source of the link.
341These links are only allowed between configfs config_items. Any
342symlink(2) attempt outside the configfs filesystem will be denied.
343
344When symlink(2) is called, the source config_item's ->allow_link()
345method is called with itself and a target item. If the source item
346allows linking to target item, it returns 0. A source item may wish to
347reject a link if it only wants links to a certain type of object (say,
348in its own subsystem).
349
350When unlink(2) is called on the symbolic link, the source item is
351notified via the ->drop_link() method. Like the ->drop_item() method,
352this is a void function and cannot return failure. The subsystem is
353responsible for responding to the change.
354
355A config_item cannot be removed while it links to any other item, nor
356can it be removed while an item links to it. Dangling symlinks are not
357allowed in configfs.
358
359[Automatically Created Subgroups]
360
361A new config_group may want to have two types of child config_items.
362While this could be codified by magic names in ->make_item(), it is much
363more explicit to have a method whereby userspace sees this divergence.
364
365Rather than have a group where some items behave differently than
366others, configfs provides a method whereby one or many subgroups are
367automatically created inside the parent at its creation. Thus,
368mkdir("parent) results in "parent", "parent/subgroup1", up through
369"parent/subgroupN". Items of type 1 can now be created in
370"parent/subgroup1", and items of type N can be created in
371"parent/subgroupN".
372
373These automatic subgroups, or default groups, do not preclude other
374children of the parent group. If ct_group_ops->make_group() exists,
375other child groups can be created on the parent group directly.
376
377A configfs subsystem specifies default groups by filling in the
378NULL-terminated array default_groups on the config_group structure.
379Each group in that array is populated in the configfs tree at the same
380time as the parent group. Similarly, they are removed at the same time
381as the parent. No extra notification is provided. When a ->drop_item()
382method call notifies the subsystem the parent group is going away, it
383also means every default group child associated with that parent group.
384
385As a consequence of this, default_groups cannot be removed directly via
386rmdir(2). They also are not considered when rmdir(2) on the parent
387group is checking for children.
388
389[Committable Items]
390
391NOTE: Committable items are currently unimplemented.
392
393Some config_items cannot have a valid initial state. That is, no
394default values can be specified for the item's attributes such that the
395item can do its work. Userspace must configure one or more attributes,
396after which the subsystem can start whatever entity this item
397represents.
398
399Consider the FakeNBD device from above. Without a target address *and*
400a target device, the subsystem has no idea what block device to import.
401The simple example assumes that the subsystem merely waits until all the
402appropriate attributes are configured, and then connects. This will,
403indeed, work, but now every attribute store must check if the attributes
404are initialized. Every attribute store must fire off the connection if
405that condition is met.
406
407Far better would be an explicit action notifying the subsystem that the
408config_item is ready to go. More importantly, an explicit action allows
409the subsystem to provide feedback as to whether the attibutes are
410initialized in a way that makes sense. configfs provides this as
411committable items.
412
413configfs still uses only normal filesystem operations. An item is
414committed via rename(2). The item is moved from a directory where it
415can be modified to a directory where it cannot.
416
417Any group that provides the ct_group_ops->commit_item() method has
418committable items. When this group appears in configfs, mkdir(2) will
419not work directly in the group. Instead, the group will have two
420subdirectories: "live" and "pending". The "live" directory does not
421support mkdir(2) or rmdir(2) either. It only allows rename(2). The
422"pending" directory does allow mkdir(2) and rmdir(2). An item is
423created in the "pending" directory. Its attributes can be modified at
424will. Userspace commits the item by renaming it into the "live"
425directory. At this point, the subsystem recieves the ->commit_item()
426callback. If all required attributes are filled to satisfaction, the
427method returns zero and the item is moved to the "live" directory.
428
429As rmdir(2) does not work in the "live" directory, an item must be
430shutdown, or "uncommitted". Again, this is done via rename(2), this
431time from the "live" directory back to the "pending" one. The subsystem
432is notified by the ct_group_ops->uncommit_object() method.
433
434
diff --git a/Documentation/filesystems/configfs/configfs_example.c b/Documentation/filesystems/configfs/configfs_example.c
new file mode 100644
index 000000000000..f3c6e4946f98
--- /dev/null
+++ b/Documentation/filesystems/configfs/configfs_example.c
@@ -0,0 +1,474 @@
1/*
2 * vim: noexpandtab ts=8 sts=0 sw=8:
3 *
4 * configfs_example.c - This file is a demonstration module containing
5 * a number of configfs subsystems.
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public
9 * License as published by the Free Software Foundation; either
10 * version 2 of the License, or (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public
18 * License along with this program; if not, write to the
19 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
20 * Boston, MA 021110-1307, USA.
21 *
22 * Based on sysfs:
23 * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
24 *
25 * configfs Copyright (C) 2005 Oracle. All rights reserved.
26 */
27
28#include <linux/init.h>
29#include <linux/module.h>
30#include <linux/slab.h>
31
32#include <linux/configfs.h>
33
34
35
36/*
37 * 01-childless
38 *
39 * This first example is a childless subsystem. It cannot create
40 * any config_items. It just has attributes.
41 *
42 * Note that we are enclosing the configfs_subsystem inside a container.
43 * This is not necessary if a subsystem has no attributes directly
44 * on the subsystem. See the next example, 02-simple-children, for
45 * such a subsystem.
46 */
47
48struct childless {
49 struct configfs_subsystem subsys;
50 int showme;
51 int storeme;
52};
53
54struct childless_attribute {
55 struct configfs_attribute attr;
56 ssize_t (*show)(struct childless *, char *);
57 ssize_t (*store)(struct childless *, const char *, size_t);
58};
59
60static inline struct childless *to_childless(struct config_item *item)
61{
62 return item ? container_of(to_configfs_subsystem(to_config_group(item)), struct childless, subsys) : NULL;
63}
64
65static ssize_t childless_showme_read(struct childless *childless,
66 char *page)
67{
68 ssize_t pos;
69
70 pos = sprintf(page, "%d\n", childless->showme);
71 childless->showme++;
72
73 return pos;
74}
75
76static ssize_t childless_storeme_read(struct childless *childless,
77 char *page)
78{
79 return sprintf(page, "%d\n", childless->storeme);
80}
81
82static ssize_t childless_storeme_write(struct childless *childless,
83 const char *page,
84 size_t count)
85{
86 unsigned long tmp;
87 char *p = (char *) page;
88
89 tmp = simple_strtoul(p, &p, 10);
90 if (!p || (*p && (*p != '\n')))
91 return -EINVAL;
92
93 if (tmp > INT_MAX)
94 return -ERANGE;
95
96 childless->storeme = tmp;
97
98 return count;
99}
100
101static ssize_t childless_description_read(struct childless *childless,
102 char *page)
103{
104 return sprintf(page,
105"[01-childless]\n"
106"\n"
107"The childless subsystem is the simplest possible subsystem in\n"
108"configfs. It does not support the creation of child config_items.\n"
109"It only has a few attributes. In fact, it isn't much different\n"
110"than a directory in /proc.\n");
111}
112
113static struct childless_attribute childless_attr_showme = {
114 .attr = { .ca_owner = THIS_MODULE, .ca_name = "showme", .ca_mode = S_IRUGO },
115 .show = childless_showme_read,
116};
117static struct childless_attribute childless_attr_storeme = {
118 .attr = { .ca_owner = THIS_MODULE, .ca_name = "storeme", .ca_mode = S_IRUGO | S_IWUSR },
119 .show = childless_storeme_read,
120 .store = childless_storeme_write,
121};
122static struct childless_attribute childless_attr_description = {
123 .attr = { .ca_owner = THIS_MODULE, .ca_name = "description", .ca_mode = S_IRUGO },
124 .show = childless_description_read,
125};
126
127static struct configfs_attribute *childless_attrs[] = {
128 &childless_attr_showme.attr,
129 &childless_attr_storeme.attr,
130 &childless_attr_description.attr,
131 NULL,
132};
133
134static ssize_t childless_attr_show(struct config_item *item,
135 struct configfs_attribute *attr,
136 char *page)
137{
138 struct childless *childless = to_childless(item);
139 struct childless_attribute *childless_attr =
140 container_of(attr, struct childless_attribute, attr);
141 ssize_t ret = 0;
142
143 if (childless_attr->show)
144 ret = childless_attr->show(childless, page);
145 return ret;
146}
147
148static ssize_t childless_attr_store(struct config_item *item,
149 struct configfs_attribute *attr,
150 const char *page, size_t count)
151{
152 struct childless *childless = to_childless(item);
153 struct childless_attribute *childless_attr =
154 container_of(attr, struct childless_attribute, attr);
155 ssize_t ret = -EINVAL;
156
157 if (childless_attr->store)
158 ret = childless_attr->store(childless, page, count);
159 return ret;
160}
161
162static struct configfs_item_operations childless_item_ops = {
163 .show_attribute = childless_attr_show,
164 .store_attribute = childless_attr_store,
165};
166
167static struct config_item_type childless_type = {
168 .ct_item_ops = &childless_item_ops,
169 .ct_attrs = childless_attrs,
170 .ct_owner = THIS_MODULE,
171};
172
173static struct childless childless_subsys = {
174 .subsys = {
175 .su_group = {
176 .cg_item = {
177 .ci_namebuf = "01-childless",
178 .ci_type = &childless_type,
179 },
180 },
181 },
182};
183
184
185/* ----------------------------------------------------------------- */
186
187/*
188 * 02-simple-children
189 *
190 * This example merely has a simple one-attribute child. Note that
191 * there is no extra attribute structure, as the child's attribute is
192 * known from the get-go. Also, there is no container for the
193 * subsystem, as it has no attributes of its own.
194 */
195
196struct simple_child {
197 struct config_item item;
198 int storeme;
199};
200
201static inline struct simple_child *to_simple_child(struct config_item *item)
202{
203 return item ? container_of(item, struct simple_child, item) : NULL;
204}
205
206static struct configfs_attribute simple_child_attr_storeme = {
207 .ca_owner = THIS_MODULE,
208 .ca_name = "storeme",
209 .ca_mode = S_IRUGO | S_IWUSR,
210};
211
212static struct configfs_attribute *simple_child_attrs[] = {
213 &simple_child_attr_storeme,
214 NULL,
215};
216
217static ssize_t simple_child_attr_show(struct config_item *item,
218 struct configfs_attribute *attr,
219 char *page)
220{
221 ssize_t count;
222 struct simple_child *simple_child = to_simple_child(item);
223
224 count = sprintf(page, "%d\n", simple_child->storeme);
225
226 return count;
227}
228
229static ssize_t simple_child_attr_store(struct config_item *item,
230 struct configfs_attribute *attr,
231 const char *page, size_t count)
232{
233 struct simple_child *simple_child = to_simple_child(item);
234 unsigned long tmp;
235 char *p = (char *) page;
236
237 tmp = simple_strtoul(p, &p, 10);
238 if (!p || (*p && (*p != '\n')))
239 return -EINVAL;
240
241 if (tmp > INT_MAX)
242 return -ERANGE;
243
244 simple_child->storeme = tmp;
245
246 return count;
247}
248
249static void simple_child_release(struct config_item *item)
250{
251 kfree(to_simple_child(item));
252}
253
254static struct configfs_item_operations simple_child_item_ops = {
255 .release = simple_child_release,
256 .show_attribute = simple_child_attr_show,
257 .store_attribute = simple_child_attr_store,
258};
259
260static struct config_item_type simple_child_type = {
261 .ct_item_ops = &simple_child_item_ops,
262 .ct_attrs = simple_child_attrs,
263 .ct_owner = THIS_MODULE,
264};
265
266
267static struct config_item *simple_children_make_item(struct config_group *group, const char *name)
268{
269 struct simple_child *simple_child;
270
271 simple_child = kmalloc(sizeof(struct simple_child), GFP_KERNEL);
272 if (!simple_child)
273 return NULL;
274
275 memset(simple_child, 0, sizeof(struct simple_child));
276
277 config_item_init_type_name(&simple_child->item, name,
278 &simple_child_type);
279
280 simple_child->storeme = 0;
281
282 return &simple_child->item;
283}
284
285static struct configfs_attribute simple_children_attr_description = {
286 .ca_owner = THIS_MODULE,
287 .ca_name = "description",
288 .ca_mode = S_IRUGO,
289};
290
291static struct configfs_attribute *simple_children_attrs[] = {
292 &simple_children_attr_description,
293 NULL,
294};
295
296static ssize_t simple_children_attr_show(struct config_item *item,
297 struct configfs_attribute *attr,
298 char *page)
299{
300 return sprintf(page,
301"[02-simple-children]\n"
302"\n"
303"This subsystem allows the creation of child config_items. These\n"
304"items have only one attribute that is readable and writeable.\n");
305}
306
307static struct configfs_item_operations simple_children_item_ops = {
308 .show_attribute = simple_children_attr_show,
309};
310
311/*
312 * Note that, since no extra work is required on ->drop_item(),
313 * no ->drop_item() is provided.
314 */
315static struct configfs_group_operations simple_children_group_ops = {
316 .make_item = simple_children_make_item,
317};
318
319static struct config_item_type simple_children_type = {
320 .ct_item_ops = &simple_children_item_ops,
321 .ct_group_ops = &simple_children_group_ops,
322 .ct_attrs = simple_children_attrs,
323};
324
325static struct configfs_subsystem simple_children_subsys = {
326 .su_group = {
327 .cg_item = {
328 .ci_namebuf = "02-simple-children",
329 .ci_type = &simple_children_type,
330 },
331 },
332};
333
334
335/* ----------------------------------------------------------------- */
336
337/*
338 * 03-group-children
339 *
340 * This example reuses the simple_children group from above. However,
341 * the simple_children group is not the subsystem itself, it is a
342 * child of the subsystem. Creation of a group in the subsystem creates
343 * a new simple_children group. That group can then have simple_child
344 * children of its own.
345 */
346
347struct simple_children {
348 struct config_group group;
349};
350
351static struct config_group *group_children_make_group(struct config_group *group, const char *name)
352{
353 struct simple_children *simple_children;
354
355 simple_children = kmalloc(sizeof(struct simple_children),
356 GFP_KERNEL);
357 if (!simple_children)
358 return NULL;
359
360 memset(simple_children, 0, sizeof(struct simple_children));
361
362 config_group_init_type_name(&simple_children->group, name,
363 &simple_children_type);
364
365 return &simple_children->group;
366}
367
368static struct configfs_attribute group_children_attr_description = {
369 .ca_owner = THIS_MODULE,
370 .ca_name = "description",
371 .ca_mode = S_IRUGO,
372};
373
374static struct configfs_attribute *group_children_attrs[] = {
375 &group_children_attr_description,
376 NULL,
377};
378
379static ssize_t group_children_attr_show(struct config_item *item,
380 struct configfs_attribute *attr,
381 char *page)
382{
383 return sprintf(page,
384"[03-group-children]\n"
385"\n"
386"This subsystem allows the creation of child config_groups. These\n"
387"groups are like the subsystem simple-children.\n");
388}
389
390static struct configfs_item_operations group_children_item_ops = {
391 .show_attribute = group_children_attr_show,
392};
393
394/*
395 * Note that, since no extra work is required on ->drop_item(),
396 * no ->drop_item() is provided.
397 */
398static struct configfs_group_operations group_children_group_ops = {
399 .make_group = group_children_make_group,
400};
401
402static struct config_item_type group_children_type = {
403 .ct_item_ops = &group_children_item_ops,
404 .ct_group_ops = &group_children_group_ops,
405 .ct_attrs = group_children_attrs,
406};
407
408static struct configfs_subsystem group_children_subsys = {
409 .su_group = {
410 .cg_item = {
411 .ci_namebuf = "03-group-children",
412 .ci_type = &group_children_type,
413 },
414 },
415};
416
417/* ----------------------------------------------------------------- */
418
419/*
420 * We're now done with our subsystem definitions.
421 * For convenience in this module, here's a list of them all. It
422 * allows the init function to easily register them. Most modules
423 * will only have one subsystem, and will only call register_subsystem
424 * on it directly.
425 */
426static struct configfs_subsystem *example_subsys[] = {
427 &childless_subsys.subsys,
428 &simple_children_subsys,
429 &group_children_subsys,
430 NULL,
431};
432
433static int __init configfs_example_init(void)
434{
435 int ret;
436 int i;
437 struct configfs_subsystem *subsys;
438
439 for (i = 0; example_subsys[i]; i++) {
440 subsys = example_subsys[i];
441
442 config_group_init(&subsys->su_group);
443 init_MUTEX(&subsys->su_sem);
444 ret = configfs_register_subsystem(subsys);
445 if (ret) {
446 printk(KERN_ERR "Error %d while registering subsystem %s\n",
447 ret,
448 subsys->su_group.cg_item.ci_namebuf);
449 goto out_unregister;
450 }
451 }
452
453 return 0;
454
455out_unregister:
456 for (; i >= 0; i--) {
457 configfs_unregister_subsystem(example_subsys[i]);
458 }
459
460 return ret;
461}
462
463static void __exit configfs_example_exit(void)
464{
465 int i;
466
467 for (i = 0; example_subsys[i]; i++) {
468 configfs_unregister_subsystem(example_subsys[i]);
469 }
470}
471
472module_init(configfs_example_init);
473module_exit(configfs_example_exit);
474MODULE_LICENSE("GPL");
diff --git a/Documentation/filesystems/dlmfs.txt b/Documentation/filesystems/dlmfs.txt
new file mode 100644
index 000000000000..9afab845a906
--- /dev/null
+++ b/Documentation/filesystems/dlmfs.txt
@@ -0,0 +1,130 @@
1dlmfs
2==================
3A minimal DLM userspace interface implemented via a virtual file
4system.
5
6dlmfs is built with OCFS2 as it requires most of its infrastructure.
7
8Project web page: http://oss.oracle.com/projects/ocfs2
9Tools web page: http://oss.oracle.com/projects/ocfs2-tools
10OCFS2 mailing lists: http://oss.oracle.com/projects/ocfs2/mailman/
11
12All code copyright 2005 Oracle except when otherwise noted.
13
14CREDITS
15=======
16
17Some code taken from ramfs which is Copyright (C) 2000 Linus Torvalds
18and Transmeta Corp.
19
20Mark Fasheh <mark.fasheh@oracle.com>
21
22Caveats
23=======
24- Right now it only works with the OCFS2 DLM, though support for other
25 DLM implementations should not be a major issue.
26
27Mount options
28=============
29None
30
31Usage
32=====
33
34If you're just interested in OCFS2, then please see ocfs2.txt. The
35rest of this document will be geared towards those who want to use
36dlmfs for easy to setup and easy to use clustered locking in
37userspace.
38
39Setup
40=====
41
42dlmfs requires that the OCFS2 cluster infrastructure be in
43place. Please download ocfs2-tools from the above url and configure a
44cluster.
45
46You'll want to start heartbeating on a volume which all the nodes in
47your lockspace can access. The easiest way to do this is via
48ocfs2_hb_ctl (distributed with ocfs2-tools). Right now it requires
49that an OCFS2 file system be in place so that it can automatically
50find it's heartbeat area, though it will eventually support heartbeat
51against raw disks.
52
53Please see the ocfs2_hb_ctl and mkfs.ocfs2 manual pages distributed
54with ocfs2-tools.
55
56Once you're heartbeating, DLM lock 'domains' can be easily created /
57destroyed and locks within them accessed.
58
59Locking
60=======
61
62Users may access dlmfs via standard file system calls, or they can use
63'libo2dlm' (distributed with ocfs2-tools) which abstracts the file
64system calls and presents a more traditional locking api.
65
66dlmfs handles lock caching automatically for the user, so a lock
67request for an already acquired lock will not generate another DLM
68call. Userspace programs are assumed to handle their own local
69locking.
70
71Two levels of locks are supported - Shared Read, and Exlcusive.
72Also supported is a Trylock operation.
73
74For information on the libo2dlm interface, please see o2dlm.h,
75distributed with ocfs2-tools.
76
77Lock value blocks can be read and written to a resource via read(2)
78and write(2) against the fd obtained via your open(2) call. The
79maximum currently supported LVB length is 64 bytes (though that is an
80OCFS2 DLM limitation). Through this mechanism, users of dlmfs can share
81small amounts of data amongst their nodes.
82
83mkdir(2) signals dlmfs to join a domain (which will have the same name
84as the resulting directory)
85
86rmdir(2) signals dlmfs to leave the domain
87
88Locks for a given domain are represented by regular inodes inside the
89domain directory. Locking against them is done via the open(2) system
90call.
91
92The open(2) call will not return until your lock has been granted or
93an error has occurred, unless it has been instructed to do a trylock
94operation. If the lock succeeds, you'll get an fd.
95
96open(2) with O_CREAT to ensure the resource inode is created - dlmfs does
97not automatically create inodes for existing lock resources.
98
99Open Flag Lock Request Type
100--------- -----------------
101O_RDONLY Shared Read
102O_RDWR Exclusive
103
104Open Flag Resulting Locking Behavior
105--------- --------------------------
106O_NONBLOCK Trylock operation
107
108You must provide exactly one of O_RDONLY or O_RDWR.
109
110If O_NONBLOCK is also provided and the trylock operation was valid but
111could not lock the resource then open(2) will return ETXTBUSY.
112
113close(2) drops the lock associated with your fd.
114
115Modes passed to mkdir(2) or open(2) are adhered to locally. Chown is
116supported locally as well. This means you can use them to restrict
117access to the resources via dlmfs on your local node only.
118
119The resource LVB may be read from the fd in either Shared Read or
120Exclusive modes via the read(2) system call. It can be written via
121write(2) only when open in Exclusive mode.
122
123Once written, an LVB will be visible to other nodes who obtain Read
124Only or higher level locks on the resource.
125
126See Also
127========
128http://opendlm.sourceforge.net/cvsmirror/opendlm/docs/dlmbook_final.pdf
129
130For more information on the VMS distributed locking API.
diff --git a/Documentation/filesystems/ext3.txt b/Documentation/filesystems/ext3.txt
index 9840d5b8d5b9..afb1335c05d6 100644
--- a/Documentation/filesystems/ext3.txt
+++ b/Documentation/filesystems/ext3.txt
@@ -2,11 +2,11 @@
2Ext3 Filesystem 2Ext3 Filesystem
3=============== 3===============
4 4
5ext3 was originally released in September 1999. Written by Stephen Tweedie 5Ext3 was originally released in September 1999. Written by Stephen Tweedie
6for 2.2 branch, and ported to 2.4 kernels by Peter Braam, Andreas Dilger, 6for the 2.2 branch, and ported to 2.4 kernels by Peter Braam, Andreas Dilger,
7Andrew Morton, Alexander Viro, Ted Ts'o and Stephen Tweedie. 7Andrew Morton, Alexander Viro, Ted Ts'o and Stephen Tweedie.
8 8
9ext3 is ext2 filesystem enhanced with journalling capabilities. 9Ext3 is the ext2 filesystem enhanced with journalling capabilities.
10 10
11Options 11Options
12======= 12=======
@@ -14,76 +14,81 @@ Options
14When mounting an ext3 filesystem, the following option are accepted: 14When mounting an ext3 filesystem, the following option are accepted:
15(*) == default 15(*) == default
16 16
17jounal=update Update the ext3 file system's journal to the 17journal=update Update the ext3 file system's journal to the current
18 current format. 18 format.
19 19
20journal=inum When a journal already exists, this option is 20journal=inum When a journal already exists, this option is ignored.
21 ignored. Otherwise, it specifies the number of 21 Otherwise, it specifies the number of the inode which
22 the inode which will represent the ext3 file 22 will represent the ext3 file system's journal file.
23 system's journal file. 23
24journal_dev=devnum When the external journal device's major/minor numbers
25 have changed, this option allows the user to specify
26 the new journal location. The journal device is
27 identified through its new major/minor numbers encoded
28 in devnum.
24 29
25noload Don't load the journal on mounting. 30noload Don't load the journal on mounting.
26 31
27data=journal All data are committed into the journal prior 32data=journal All data are committed into the journal prior to being
28 to being written into the main file system. 33 written into the main file system.
29 34
30data=ordered (*) All data are forced directly out to the main file 35data=ordered (*) All data are forced directly out to the main file
31 system prior to its metadata being committed to 36 system prior to its metadata being committed to the
32 the journal. 37 journal.
33 38
34data=writeback Data ordering is not preserved, data may be 39data=writeback Data ordering is not preserved, data may be written
35 written into the main file system after its 40 into the main file system after its metadata has been
36 metadata has been committed to the journal. 41 committed to the journal.
37 42
38commit=nrsec (*) Ext3 can be told to sync all its data and metadata 43commit=nrsec (*) Ext3 can be told to sync all its data and metadata
39 every 'nrsec' seconds. The default value is 5 seconds. 44 every 'nrsec' seconds. The default value is 5 seconds.
40 This means that if you lose your power, you will lose, 45 This means that if you lose your power, you will lose
41 as much, the latest 5 seconds of work (your filesystem 46 as much as the latest 5 seconds of work (your
42 will not be damaged though, thanks to journaling). This 47 filesystem will not be damaged though, thanks to the
43 default value (or any low value) will hurt performance, 48 journaling). This default value (or any low value)
44 but it's good for data-safety. Setting it to 0 will 49 will hurt performance, but it's good for data-safety.
45 have the same effect than leaving the default 5 sec. 50 Setting it to 0 will have the same effect as leaving
51 it at the default (5 seconds).
46 Setting it to very large values will improve 52 Setting it to very large values will improve
47 performance. 53 performance.
48 54
49barrier=1 This enables/disables barriers. barrier=0 disables it, 55barrier=1 This enables/disables barriers. barrier=0 disables
50 barrier=1 enables it. 56 it, barrier=1 enables it.
51 57
52orlov (*) This enables the new Orlov block allocator. It's enabled 58orlov (*) This enables the new Orlov block allocator. It is
53 by default. 59 enabled by default.
54 60
55oldalloc This disables the Orlov block allocator and enables the 61oldalloc This disables the Orlov block allocator and enables
56 old block allocator. Orlov should have better performance, 62 the old block allocator. Orlov should have better
57 we'd like to get some feedback if it's the contrary for 63 performance - we'd like to get some feedback if it's
58 you. 64 the contrary for you.
59 65
60user_xattr Enables Extended User Attributes. Additionally, you need 66user_xattr Enables Extended User Attributes. Additionally, you
61 to have extended attribute support enabled in the kernel 67 need to have extended attribute support enabled in the
62 configuration (CONFIG_EXT3_FS_XATTR). See the attr(5) 68 kernel configuration (CONFIG_EXT3_FS_XATTR). See the
63 manual page and http://acl.bestbits.at to learn more 69 attr(5) manual page and http://acl.bestbits.at/ to
64 about extended attributes. 70 learn more about extended attributes.
65 71
66nouser_xattr Disables Extended User Attributes. 72nouser_xattr Disables Extended User Attributes.
67 73
68acl Enables POSIX Access Control Lists support. Additionally, 74acl Enables POSIX Access Control Lists support.
69 you need to have ACL support enabled in the kernel 75 Additionally, you need to have ACL support enabled in
70 configuration (CONFIG_EXT3_FS_POSIX_ACL). See the acl(5) 76 the kernel configuration (CONFIG_EXT3_FS_POSIX_ACL).
71 manual page and http://acl.bestbits.at for more 77 See the acl(5) manual page and http://acl.bestbits.at/
72 information. 78 for more information.
73 79
74noacl This option disables POSIX Access Control List support. 80noacl This option disables POSIX Access Control List
81 support.
75 82
76reservation 83reservation
77 84
78noreservation 85noreservation
79 86
80resize=
81
82bsddf (*) Make 'df' act like BSD. 87bsddf (*) Make 'df' act like BSD.
83minixdf Make 'df' act like Minix. 88minixdf Make 'df' act like Minix.
84 89
85check=none Don't do extra checking of bitmaps on mount. 90check=none Don't do extra checking of bitmaps on mount.
86nocheck 91nocheck
87 92
88debug Extra debugging information is sent to syslog. 93debug Extra debugging information is sent to syslog.
89 94
@@ -92,7 +97,7 @@ errors=continue Keep going on a filesystem error.
92errors=panic Panic and halt the machine if an error occurs. 97errors=panic Panic and halt the machine if an error occurs.
93 98
94grpid Give objects the same group ID as their creator. 99grpid Give objects the same group ID as their creator.
95bsdgroups 100bsdgroups
96 101
97nogrpid (*) New objects have the group ID of their creator. 102nogrpid (*) New objects have the group ID of their creator.
98sysvgroups 103sysvgroups
@@ -103,81 +108,83 @@ resuid=n The user ID which may use the reserved blocks.
103 108
104sb=n Use alternate superblock at this location. 109sb=n Use alternate superblock at this location.
105 110
106quota Quota options are currently silently ignored. 111quota
107noquota (see fs/ext3/super.c, line 594) 112noquota
108grpquota 113grpquota
109usrquota 114usrquota
110 115
111 116
112Specification 117Specification
113============= 118=============
114ext3 shares all disk implementation with ext2 filesystem, and add 119Ext3 shares all disk implementation with the ext2 filesystem, and adds
115transactions capabilities to ext2. Journaling is done by the 120transactions capabilities to ext2. Journaling is done by the Journaling Block
116Journaling block device layer. 121Device layer.
117 122
118Journaling Block Device layer 123Journaling Block Device layer
119----------------------------- 124-----------------------------
120The Journaling Block Device layer (JBD) isn't ext3 specific. It was 125The Journaling Block Device layer (JBD) isn't ext3 specific. It was design to
121design to add journaling capabilities on a block device. The ext3 126add journaling capabilities on a block device. The ext3 filesystem code will
122filesystem code will inform the JBD of modifications it is performing 127inform the JBD of modifications it is performing (called a transaction). The
123(Call a transaction). the journal support the transactions start and 128journal supports the transactions start and stop, and in case of crash, the
124stop, and in case of crash, the journal can replayed the transactions 129journal can replayed the transactions to put the partition back in a
125to put the partition on a consistent state fastly. 130consistent state fast.
126 131
127handles represent a single atomic update to a filesystem. JBD can 132Handles represent a single atomic update to a filesystem. JBD can handle an
128handle external journal on a block device. 133external journal on a block device.
129 134
130Data Mode 135Data Mode
131--------- 136---------
132There's 3 different data modes: 137There are 3 different data modes:
133 138
134* writeback mode 139* writeback mode
135In data=writeback mode, ext3 does not journal data at all. This mode 140In data=writeback mode, ext3 does not journal data at all. This mode provides
136provides a similar level of journaling as XFS, JFS, and ReiserFS in its 141a similar level of journaling as that of XFS, JFS, and ReiserFS in its default
137default mode - metadata journaling. A crash+recovery can cause 142mode - metadata journaling. A crash+recovery can cause incorrect data to
138incorrect data to appear in files which were written shortly before the 143appear in files which were written shortly before the crash. This mode will
139crash. This mode will typically provide the best ext3 performance. 144typically provide the best ext3 performance.
140 145
141* ordered mode 146* ordered mode
142In data=ordered mode, ext3 only officially journals metadata, but it 147In data=ordered mode, ext3 only officially journals metadata, but it logically
143logically groups metadata and data blocks into a single unit called a 148groups metadata and data blocks into a single unit called a transaction. When
144transaction. When it's time to write the new metadata out to disk, the 149it's time to write the new metadata out to disk, the associated data blocks
145associated data blocks are written first. In general, this mode 150are written first. In general, this mode performs slightly slower than
146perform slightly slower than writeback but significantly faster than 151writeback but significantly faster than journal mode.
147journal mode.
148 152
149* journal mode 153* journal mode
150data=journal mode provides full data and metadata journaling. All new 154data=journal mode provides full data and metadata journaling. All new data is
151data is written to the journal first, and then to its final location. 155written to the journal first, and then to its final location.
152In the event of a crash, the journal can be replayed, bringing both 156In the event of a crash, the journal can be replayed, bringing both data and
153data and metadata into a consistent state. This mode is the slowest 157metadata into a consistent state. This mode is the slowest except when data
154except when data needs to be read from and written to disk at the same 158needs to be read from and written to disk at the same time where it
155time where it outperform all others mode. 159outperforms all others modes.
156 160
157Compatibility 161Compatibility
158------------- 162-------------
159 163
160Ext2 partitions can be easily convert to ext3, with `tune2fs -j <dev>`. 164Ext2 partitions can be easily convert to ext3, with `tune2fs -j <dev>`.
161Ext3 is fully compatible with Ext2. Ext3 partitions can easily be 165Ext3 is fully compatible with Ext2. Ext3 partitions can easily be mounted as
162mounted as Ext2. 166Ext2.
167
163 168
164External Tools 169External Tools
165============== 170==============
166see manual pages to know more. 171See manual pages to learn more.
172
173tune2fs: create a ext3 journal on a ext2 partition with the -j flag.
174mke2fs: create a ext3 partition with the -j flag.
175debugfs: ext2 and ext3 file system debugger.
176ext2online: online (mounted) ext2 and ext3 filesystem resizer
167 177
168tune2fs: create a ext3 journal on a ext2 partition with the -j flags
169mke2fs: create a ext3 partition with the -j flags
170debugfs: ext2 and ext3 file system debugger
171 178
172References 179References
173========== 180==========
174 181
175kernel source: file:/usr/src/linux/fs/ext3 182kernel source: <file:fs/ext3/>
176 file:/usr/src/linux/fs/jbd 183 <file:fs/jbd/>
177 184
178programs: http://e2fsprogs.sourceforge.net 185programs: http://e2fsprogs.sourceforge.net/
186 http://ext2resize.sourceforge.net
179 187
180useful link: 188useful links: http://www.zip.com.au/~akpm/linux/ext3/ext3-usage.html
181 http://www.zip.com.au/~akpm/linux/ext3/ext3-usage.html
182 http://www-106.ibm.com/developerworks/linux/library/l-fs7/ 189 http://www-106.ibm.com/developerworks/linux/library/l-fs7/
183 http://www-106.ibm.com/developerworks/linux/library/l-fs8/ 190 http://www-106.ibm.com/developerworks/linux/library/l-fs8/
diff --git a/Documentation/filesystems/fuse.txt b/Documentation/filesystems/fuse.txt
index 6b5741e651a2..33f74310d161 100644
--- a/Documentation/filesystems/fuse.txt
+++ b/Documentation/filesystems/fuse.txt
@@ -86,6 +86,62 @@ Mount options
86 The default is infinite. Note that the size of read requests is 86 The default is infinite. Note that the size of read requests is
87 limited anyway to 32 pages (which is 128kbyte on i386). 87 limited anyway to 32 pages (which is 128kbyte on i386).
88 88
89Sysfs
90~~~~~
91
92FUSE sets up the following hierarchy in sysfs:
93
94 /sys/fs/fuse/connections/N/
95
96where N is an increasing number allocated to each new connection.
97
98For each connection the following attributes are defined:
99
100 'waiting'
101
102 The number of requests which are waiting to be transfered to
103 userspace or being processed by the filesystem daemon. If there is
104 no filesystem activity and 'waiting' is non-zero, then the
105 filesystem is hung or deadlocked.
106
107 'abort'
108
109 Writing anything into this file will abort the filesystem
110 connection. This means that all waiting requests will be aborted an
111 error returned for all aborted and new requests.
112
113Only a privileged user may read or write these attributes.
114
115Aborting a filesystem connection
116~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
117
118It is possible to get into certain situations where the filesystem is
119not responding. Reasons for this may be:
120
121 a) Broken userspace filesystem implementation
122
123 b) Network connection down
124
125 c) Accidental deadlock
126
127 d) Malicious deadlock
128
129(For more on c) and d) see later sections)
130
131In either of these cases it may be useful to abort the connection to
132the filesystem. There are several ways to do this:
133
134 - Kill the filesystem daemon. Works in case of a) and b)
135
136 - Kill the filesystem daemon and all users of the filesystem. Works
137 in all cases except some malicious deadlocks
138
139 - Use forced umount (umount -f). Works in all cases but only if
140 filesystem is still attached (it hasn't been lazy unmounted)
141
142 - Abort filesystem through the sysfs interface. Most powerful
143 method, always works.
144
89How do non-privileged mounts work? 145How do non-privileged mounts work?
90~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 146~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
91 147
@@ -313,3 +369,10 @@ faulted with get_user_pages(). The 'req->locked' flag indicates
313when the copy is taking place, and interruption is delayed until 369when the copy is taking place, and interruption is delayed until
314this flag is unset. 370this flag is unset.
315 371
372Scenario 3 - Tricky deadlock with asynchronous read
373---------------------------------------------------
374
375The same situation as above, except thread-1 will wait on page lock
376and hence it will be uninterruptible as well. The solution is to
377abort the connection with forced umount (if mount is attached) or
378through the abort attribute in sysfs.
diff --git a/Documentation/filesystems/ocfs2.txt b/Documentation/filesystems/ocfs2.txt
new file mode 100644
index 000000000000..f2595caf052e
--- /dev/null
+++ b/Documentation/filesystems/ocfs2.txt
@@ -0,0 +1,55 @@
1OCFS2 filesystem
2==================
3OCFS2 is a general purpose extent based shared disk cluster file
4system with many similarities to ext3. It supports 64 bit inode
5numbers, and has automatically extending metadata groups which may
6also make it attractive for non-clustered use.
7
8You'll want to install the ocfs2-tools package in order to at least
9get "mount.ocfs2" and "ocfs2_hb_ctl".
10
11Project web page: http://oss.oracle.com/projects/ocfs2
12Tools web page: http://oss.oracle.com/projects/ocfs2-tools
13OCFS2 mailing lists: http://oss.oracle.com/projects/ocfs2/mailman/
14
15All code copyright 2005 Oracle except when otherwise noted.
16
17CREDITS:
18Lots of code taken from ext3 and other projects.
19
20Authors in alphabetical order:
21Joel Becker <joel.becker@oracle.com>
22Zach Brown <zach.brown@oracle.com>
23Mark Fasheh <mark.fasheh@oracle.com>
24Kurt Hackel <kurt.hackel@oracle.com>
25Sunil Mushran <sunil.mushran@oracle.com>
26Manish Singh <manish.singh@oracle.com>
27
28Caveats
29=======
30Features which OCFS2 does not support yet:
31 - sparse files
32 - extended attributes
33 - shared writeable mmap
34 - loopback is supported, but data written will not
35 be cluster coherent.
36 - quotas
37 - cluster aware flock
38 - Directory change notification (F_NOTIFY)
39 - Distributed Caching (F_SETLEASE/F_GETLEASE/break_lease)
40 - POSIX ACLs
41 - readpages / writepages (not user visible)
42
43Mount options
44=============
45
46OCFS2 supports the following mount options:
47(*) == default
48
49barrier=1 This enables/disables barriers. barrier=0 disables it,
50 barrier=1 enables it.
51errors=remount-ro(*) Remount the filesystem read-only on an error.
52errors=panic Panic and halt the machine if an error occurs.
53intr (*) Allow signals to interrupt cluster operations.
54nointr Do not allow signals to interrupt cluster
55 operations.
diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index d4773565ea2f..944cf109a6f5 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -418,7 +418,7 @@ VmallocChunk: 111088 kB
418 Dirty: Memory which is waiting to get written back to the disk 418 Dirty: Memory which is waiting to get written back to the disk
419 Writeback: Memory which is actively being written back to the disk 419 Writeback: Memory which is actively being written back to the disk
420 Mapped: files which have been mmaped, such as libraries 420 Mapped: files which have been mmaped, such as libraries
421 Slab: in-kernel data structures cache 421 Slab: in-kernel data structures cache
422 CommitLimit: Based on the overcommit ratio ('vm.overcommit_ratio'), 422 CommitLimit: Based on the overcommit ratio ('vm.overcommit_ratio'),
423 this is the total amount of memory currently available to 423 this is the total amount of memory currently available to
424 be allocated on the system. This limit is only adhered to 424 be allocated on the system. This limit is only adhered to
@@ -1302,6 +1302,23 @@ VM has token based thrashing control mechanism and uses the token to prevent
1302unnecessary page faults in thrashing situation. The unit of the value is 1302unnecessary page faults in thrashing situation. The unit of the value is
1303second. The value would be useful to tune thrashing behavior. 1303second. The value would be useful to tune thrashing behavior.
1304 1304
1305drop_caches
1306-----------
1307
1308Writing to this will cause the kernel to drop clean caches, dentries and
1309inodes from memory, causing that memory to become free.
1310
1311To free pagecache:
1312 echo 1 > /proc/sys/vm/drop_caches
1313To free dentries and inodes:
1314 echo 2 > /proc/sys/vm/drop_caches
1315To free pagecache, dentries and inodes:
1316 echo 3 > /proc/sys/vm/drop_caches
1317
1318As this is a non-destructive operation and dirty objects are not freeable, the
1319user should run `sync' first.
1320
1321
13052.5 /proc/sys/dev - Device specific parameters 13222.5 /proc/sys/dev - Device specific parameters
1306---------------------------------------------- 1323----------------------------------------------
1307 1324
diff --git a/Documentation/filesystems/ramfs-rootfs-initramfs.txt b/Documentation/filesystems/ramfs-rootfs-initramfs.txt
index b3404a032596..60ab61e54e8a 100644
--- a/Documentation/filesystems/ramfs-rootfs-initramfs.txt
+++ b/Documentation/filesystems/ramfs-rootfs-initramfs.txt
@@ -143,12 +143,26 @@ as the following example:
143 dir /mnt 755 0 0 143 dir /mnt 755 0 0
144 file /init initramfs/init.sh 755 0 0 144 file /init initramfs/init.sh 755 0 0
145 145
146Run "usr/gen_init_cpio" (after the kernel build) to get a usage message
147documenting the above file format.
148
146One advantage of the text file is that root access is not required to 149One advantage of the text file is that root access is not required to
147set permissions or create device nodes in the new archive. (Note that those 150set permissions or create device nodes in the new archive. (Note that those
148two example "file" entries expect to find files named "init.sh" and "busybox" in 151two example "file" entries expect to find files named "init.sh" and "busybox" in
149a directory called "initramfs", under the linux-2.6.* directory. See 152a directory called "initramfs", under the linux-2.6.* directory. See
150Documentation/early-userspace/README for more details.) 153Documentation/early-userspace/README for more details.)
151 154
155The kernel does not depend on external cpio tools, gen_init_cpio is created
156from usr/gen_init_cpio.c which is entirely self-contained, and the kernel's
157boot-time extractor is also (obviously) self-contained. However, if you _do_
158happen to have cpio installed, the following command line can extract the
159generated cpio image back into its component files:
160
161 cpio -i -d -H newc -F initramfs_data.cpio --no-absolute-filenames
162
163Contents of initramfs:
164----------------------
165
152If you don't already understand what shared libraries, devices, and paths 166If you don't already understand what shared libraries, devices, and paths
153you need to get a minimal root filesystem up and running, here are some 167you need to get a minimal root filesystem up and running, here are some
154references: 168references:
@@ -161,13 +175,69 @@ designed to be a tiny C library to statically link early userspace
161code against, along with some related utilities. It is BSD licensed. 175code against, along with some related utilities. It is BSD licensed.
162 176
163I use uClibc (http://www.uclibc.org) and busybox (http://www.busybox.net) 177I use uClibc (http://www.uclibc.org) and busybox (http://www.busybox.net)
164myself. These are LGPL and GPL, respectively. 178myself. These are LGPL and GPL, respectively. (A self-contained initramfs
179package is planned for the busybox 1.2 release.)
165 180
166In theory you could use glibc, but that's not well suited for small embedded 181In theory you could use glibc, but that's not well suited for small embedded
167uses like this. (A "hello world" program statically linked against glibc is 182uses like this. (A "hello world" program statically linked against glibc is
168over 400k. With uClibc it's 7k. Also note that glibc dlopens libnss to do 183over 400k. With uClibc it's 7k. Also note that glibc dlopens libnss to do
169name lookups, even when otherwise statically linked.) 184name lookups, even when otherwise statically linked.)
170 185
186Why cpio rather than tar?
187-------------------------
188
189This decision was made back in December, 2001. The discussion started here:
190
191 http://www.uwsg.iu.edu/hypermail/linux/kernel/0112.2/1538.html
192
193And spawned a second thread (specifically on tar vs cpio), starting here:
194
195 http://www.uwsg.iu.edu/hypermail/linux/kernel/0112.2/1587.html
196
197The quick and dirty summary version (which is no substitute for reading
198the above threads) is:
199
2001) cpio is a standard. It's decades old (from the AT&T days), and already
201 widely used on Linux (inside RPM, Red Hat's device driver disks). Here's
202 a Linux Journal article about it from 1996:
203
204 http://www.linuxjournal.com/article/1213
205
206 It's not as popular as tar because the traditional cpio command line tools
207 require _truly_hideous_ command line arguments. But that says nothing
208 either way about the archive format, and there are alternative tools,
209 such as:
210
211 http://freshmeat.net/projects/afio/
212
2132) The cpio archive format chosen by the kernel is simpler and cleaner (and
214 thus easier to create and parse) than any of the (literally dozens of)
215 various tar archive formats. The complete initramfs archive format is
216 explained in buffer-format.txt, created in usr/gen_init_cpio.c, and
217 extracted in init/initramfs.c. All three together come to less than 26k
218 total of human-readable text.
219
2203) The GNU project standardizing on tar is approximately as relevant as
221 Windows standardizing on zip. Linux is not part of either, and is free
222 to make its own technical decisions.
223
2244) Since this is a kernel internal format, it could easily have been
225 something brand new. The kernel provides its own tools to create and
226 extract this format anyway. Using an existing standard was preferable,
227 but not essential.
228
2295) Al Viro made the decision (quote: "tar is ugly as hell and not going to be
230 supported on the kernel side"):
231
232 http://www.uwsg.iu.edu/hypermail/linux/kernel/0112.2/1540.html
233
234 explained his reasoning:
235
236 http://www.uwsg.iu.edu/hypermail/linux/kernel/0112.2/1550.html
237 http://www.uwsg.iu.edu/hypermail/linux/kernel/0112.2/1638.html
238
239 and, most importantly, designed and implemented the initramfs code.
240
171Future directions: 241Future directions:
172------------------ 242------------------
173 243
diff --git a/Documentation/filesystems/relayfs.txt b/Documentation/filesystems/relayfs.txt
index d803abed29f0..5832377b7340 100644
--- a/Documentation/filesystems/relayfs.txt
+++ b/Documentation/filesystems/relayfs.txt
@@ -44,30 +44,41 @@ relayfs can operate in a mode where it will overwrite data not yet
44collected by userspace, and not wait for it to consume it. 44collected by userspace, and not wait for it to consume it.
45 45
46relayfs itself does not provide for communication of such data between 46relayfs itself does not provide for communication of such data between
47userspace and kernel, allowing the kernel side to remain simple and not 47userspace and kernel, allowing the kernel side to remain simple and
48impose a single interface on userspace. It does provide a separate 48not impose a single interface on userspace. It does provide a set of
49helper though, described below. 49examples and a separate helper though, described below.
50
51klog and relay-apps example code
52================================
53
54relayfs itself is ready to use, but to make things easier, a couple
55simple utility functions and a set of examples are provided.
56
57The relay-apps example tarball, available on the relayfs sourceforge
58site, contains a set of self-contained examples, each consisting of a
59pair of .c files containing boilerplate code for each of the user and
60kernel sides of a relayfs application; combined these two sets of
61boilerplate code provide glue to easily stream data to disk, without
62having to bother with mundane housekeeping chores.
63
64The 'klog debugging functions' patch (klog.patch in the relay-apps
65tarball) provides a couple of high-level logging functions to the
66kernel which allow writing formatted text or raw data to a channel,
67regardless of whether a channel to write into exists or not, or
68whether relayfs is compiled into the kernel or is configured as a
69module. These functions allow you to put unconditional 'trace'
70statements anywhere in the kernel or kernel modules; only when there
71is a 'klog handler' registered will data actually be logged (see the
72klog and kleak examples for details).
73
74It is of course possible to use relayfs from scratch i.e. without
75using any of the relay-apps example code or klog, but you'll have to
76implement communication between userspace and kernel, allowing both to
77convey the state of buffers (full, empty, amount of padding).
78
79klog and the relay-apps examples can be found in the relay-apps
80tarball on http://relayfs.sourceforge.net
50 81
51klog, relay-app & librelay
52==========================
53
54relayfs itself is ready to use, but to make things easier, two
55additional systems are provided. klog is a simple wrapper to make
56writing formatted text or raw data to a channel simpler, regardless of
57whether a channel to write into exists or not, or whether relayfs is
58compiled into the kernel or is configured as a module. relay-app is
59the kernel counterpart of userspace librelay.c, combined these two
60files provide glue to easily stream data to disk, without having to
61bother with housekeeping. klog and relay-app can be used together,
62with klog providing high-level logging functions to the kernel and
63relay-app taking care of kernel-user control and disk-logging chores.
64
65It is possible to use relayfs without relay-app & librelay, but you'll
66have to implement communication between userspace and kernel, allowing
67both to convey the state of buffers (full, empty, amount of padding).
68
69klog, relay-app and librelay can be found in the relay-apps tarball on
70http://relayfs.sourceforge.net
71 82
72The relayfs user space API 83The relayfs user space API
73========================== 84==========================
@@ -125,6 +136,8 @@ Here's a summary of the API relayfs provides to in-kernel clients:
125 relay_reset(chan) 136 relay_reset(chan)
126 relayfs_create_dir(name, parent) 137 relayfs_create_dir(name, parent)
127 relayfs_remove_dir(dentry) 138 relayfs_remove_dir(dentry)
139 relayfs_create_file(name, parent, mode, fops, data)
140 relayfs_remove_file(dentry)
128 141
129 channel management typically called on instigation of userspace: 142 channel management typically called on instigation of userspace:
130 143
@@ -141,6 +154,8 @@ Here's a summary of the API relayfs provides to in-kernel clients:
141 subbuf_start(buf, subbuf, prev_subbuf, prev_padding) 154 subbuf_start(buf, subbuf, prev_subbuf, prev_padding)
142 buf_mapped(buf, filp) 155 buf_mapped(buf, filp)
143 buf_unmapped(buf, filp) 156 buf_unmapped(buf, filp)
157 create_buf_file(filename, parent, mode, buf, is_global)
158 remove_buf_file(dentry)
144 159
145 helper functions: 160 helper functions:
146 161
@@ -320,6 +335,71 @@ forces a sub-buffer switch on all the channel buffers, and can be used
320to finalize and process the last sub-buffers before the channel is 335to finalize and process the last sub-buffers before the channel is
321closed. 336closed.
322 337
338Creating non-relay files
339------------------------
340
341relay_open() automatically creates files in the relayfs filesystem to
342represent the per-cpu kernel buffers; it's often useful for
343applications to be able to create their own files alongside the relay
344files in the relayfs filesystem as well e.g. 'control' files much like
345those created in /proc or debugfs for similar purposes, used to
346communicate control information between the kernel and user sides of a
347relayfs application. For this purpose the relayfs_create_file() and
348relayfs_remove_file() API functions exist. For relayfs_create_file(),
349the caller passes in a set of user-defined file operations to be used
350for the file and an optional void * to a user-specified data item,
351which will be accessible via inode->u.generic_ip (see the relay-apps
352tarball for examples). The file_operations are a required parameter
353to relayfs_create_file() and thus the semantics of these files are
354completely defined by the caller.
355
356See the relay-apps tarball at http://relayfs.sourceforge.net for
357examples of how these non-relay files are meant to be used.
358
359Creating relay files in other filesystems
360-----------------------------------------
361
362By default of course, relay_open() creates relay files in the relayfs
363filesystem. Because relay_file_operations is exported, however, it's
364also possible to create and use relay files in other pseudo-filesytems
365such as debugfs.
366
367For this purpose, two callback functions are provided,
368create_buf_file() and remove_buf_file(). create_buf_file() is called
369once for each per-cpu buffer from relay_open() to allow the client to
370create a file to be used to represent the corresponding buffer; if
371this callback is not defined, the default implementation will create
372and return a file in the relayfs filesystem to represent the buffer.
373The callback should return the dentry of the file created to represent
374the relay buffer. Note that the parent directory passed to
375relay_open() (and passed along to the callback), if specified, must
376exist in the same filesystem the new relay file is created in. If
377create_buf_file() is defined, remove_buf_file() must also be defined;
378it's responsible for deleting the file(s) created in create_buf_file()
379and is called during relay_close().
380
381The create_buf_file() implementation can also be defined in such a way
382as to allow the creation of a single 'global' buffer instead of the
383default per-cpu set. This can be useful for applications interested
384mainly in seeing the relative ordering of system-wide events without
385the need to bother with saving explicit timestamps for the purpose of
386merging/sorting per-cpu files in a postprocessing step.
387
388To have relay_open() create a global buffer, the create_buf_file()
389implementation should set the value of the is_global outparam to a
390non-zero value in addition to creating the file that will be used to
391represent the single buffer. In the case of a global buffer,
392create_buf_file() and remove_buf_file() will be called only once. The
393normal channel-writing functions e.g. relay_write() can still be used
394- writes from any cpu will transparently end up in the global buffer -
395but since it is a global buffer, callers should make sure they use the
396proper locking for such a buffer, either by wrapping writes in a
397spinlock, or by copying a write function from relayfs_fs.h and
398creating a local version that internally does the proper locking.
399
400See the 'exported-relayfile' examples in the relay-apps tarball for
401examples of creating and using relay files in debugfs.
402
323Misc 403Misc
324---- 404----
325 405
diff --git a/Documentation/filesystems/spufs.txt b/Documentation/filesystems/spufs.txt
new file mode 100644
index 000000000000..8edc3952eff4
--- /dev/null
+++ b/Documentation/filesystems/spufs.txt
@@ -0,0 +1,521 @@
1SPUFS(2) Linux Programmer's Manual SPUFS(2)
2
3
4
5NAME
6 spufs - the SPU file system
7
8
9DESCRIPTION
10 The SPU file system is used on PowerPC machines that implement the Cell
11 Broadband Engine Architecture in order to access Synergistic Processor
12 Units (SPUs).
13
14 The file system provides a name space similar to posix shared memory or
15 message queues. Users that have write permissions on the file system
16 can use spu_create(2) to establish SPU contexts in the spufs root.
17
18 Every SPU context is represented by a directory containing a predefined
19 set of files. These files can be used for manipulating the state of the
20 logical SPU. Users can change permissions on those files, but not actu-
21 ally add or remove files.
22
23
24MOUNT OPTIONS
25 uid=<uid>
26 set the user owning the mount point, the default is 0 (root).
27
28 gid=<gid>
29 set the group owning the mount point, the default is 0 (root).
30
31
32FILES
33 The files in spufs mostly follow the standard behavior for regular sys-
34 tem calls like read(2) or write(2), but often support only a subset of
35 the operations supported on regular file systems. This list details the
36 supported operations and the deviations from the behaviour in the
37 respective man pages.
38
39 All files that support the read(2) operation also support readv(2) and
40 all files that support the write(2) operation also support writev(2).
41 All files support the access(2) and stat(2) family of operations, but
42 only the st_mode, st_nlink, st_uid and st_gid fields of struct stat
43 contain reliable information.
44
45 All files support the chmod(2)/fchmod(2) and chown(2)/fchown(2) opera-
46 tions, but will not be able to grant permissions that contradict the
47 possible operations, e.g. read access on the wbox file.
48
49 The current set of files is:
50
51
52 /mem
53 the contents of the local storage memory of the SPU. This can be
54 accessed like a regular shared memory file and contains both code and
55 data in the address space of the SPU. The possible operations on an
56 open mem file are:
57
58 read(2), pread(2), write(2), pwrite(2), lseek(2)
59 These operate as documented, with the exception that seek(2),
60 write(2) and pwrite(2) are not supported beyond the end of the
61 file. The file size is the size of the local storage of the SPU,
62 which normally is 256 kilobytes.
63
64 mmap(2)
65 Mapping mem into the process address space gives access to the
66 SPU local storage within the process address space. Only
67 MAP_SHARED mappings are allowed.
68
69
70 /mbox
71 The first SPU to CPU communication mailbox. This file is read-only and
72 can be read in units of 32 bits. The file can only be used in non-
73 blocking mode and it even poll() will not block on it. The possible
74 operations on an open mbox file are:
75
76 read(2)
77 If a count smaller than four is requested, read returns -1 and
78 sets errno to EINVAL. If there is no data available in the mail
79 box, the return value is set to -1 and errno becomes EAGAIN.
80 When data has been read successfully, four bytes are placed in
81 the data buffer and the value four is returned.
82
83
84 /ibox
85 The second SPU to CPU communication mailbox. This file is similar to
86 the first mailbox file, but can be read in blocking I/O mode, and the
87 poll familiy of system calls can be used to wait for it. The possible
88 operations on an open ibox file are:
89
90 read(2)
91 If a count smaller than four is requested, read returns -1 and
92 sets errno to EINVAL. If there is no data available in the mail
93 box and the file descriptor has been opened with O_NONBLOCK, the
94 return value is set to -1 and errno becomes EAGAIN.
95
96 If there is no data available in the mail box and the file
97 descriptor has been opened without O_NONBLOCK, the call will
98 block until the SPU writes to its interrupt mailbox channel.
99 When data has been read successfully, four bytes are placed in
100 the data buffer and the value four is returned.
101
102 poll(2)
103 Poll on the ibox file returns (POLLIN | POLLRDNORM) whenever
104 data is available for reading.
105
106
107 /wbox
108 The CPU to SPU communation mailbox. It is write-only can can be written
109 in units of 32 bits. If the mailbox is full, write() will block and
110 poll can be used to wait for it becoming empty again. The possible
111 operations on an open wbox file are: write(2) If a count smaller than
112 four is requested, write returns -1 and sets errno to EINVAL. If there
113 is no space available in the mail box and the file descriptor has been
114 opened with O_NONBLOCK, the return value is set to -1 and errno becomes
115 EAGAIN.
116
117 If there is no space available in the mail box and the file descriptor
118 has been opened without O_NONBLOCK, the call will block until the SPU
119 reads from its PPE mailbox channel. When data has been read success-
120 fully, four bytes are placed in the data buffer and the value four is
121 returned.
122
123 poll(2)
124 Poll on the ibox file returns (POLLOUT | POLLWRNORM) whenever
125 space is available for writing.
126
127
128 /mbox_stat
129 /ibox_stat
130 /wbox_stat
131 Read-only files that contain the length of the current queue, i.e. how
132 many words can be read from mbox or ibox or how many words can be
133 written to wbox without blocking. The files can be read only in 4-byte
134 units and return a big-endian binary integer number. The possible
135 operations on an open *box_stat file are:
136
137 read(2)
138 If a count smaller than four is requested, read returns -1 and
139 sets errno to EINVAL. Otherwise, a four byte value is placed in
140 the data buffer, containing the number of elements that can be
141 read from (for mbox_stat and ibox_stat) or written to (for
142 wbox_stat) the respective mail box without blocking or resulting
143 in EAGAIN.
144
145
146 /npc
147 /decr
148 /decr_status
149 /spu_tag_mask
150 /event_mask
151 /srr0
152 Internal registers of the SPU. The representation is an ASCII string
153 with the numeric value of the next instruction to be executed. These
154 can be used in read/write mode for debugging, but normal operation of
155 programs should not rely on them because access to any of them except
156 npc requires an SPU context save and is therefore very inefficient.
157
158 The contents of these files are:
159
160 npc Next Program Counter
161
162 decr SPU Decrementer
163
164 decr_status Decrementer Status
165
166 spu_tag_mask MFC tag mask for SPU DMA
167
168 event_mask Event mask for SPU interrupts
169
170 srr0 Interrupt Return address register
171
172
173 The possible operations on an open npc, decr, decr_status,
174 spu_tag_mask, event_mask or srr0 file are:
175
176 read(2)
177 When the count supplied to the read call is shorter than the
178 required length for the pointer value plus a newline character,
179 subsequent reads from the same file descriptor will result in
180 completing the string, regardless of changes to the register by
181 a running SPU task. When a complete string has been read, all
182 subsequent read operations will return zero bytes and a new file
183 descriptor needs to be opened to read the value again.
184
185 write(2)
186 A write operation on the file results in setting the register to
187 the value given in the string. The string is parsed from the
188 beginning to the first non-numeric character or the end of the
189 buffer. Subsequent writes to the same file descriptor overwrite
190 the previous setting.
191
192
193 /fpcr
194 This file gives access to the Floating Point Status and Control Regis-
195 ter as a four byte long file. The operations on the fpcr file are:
196
197 read(2)
198 If a count smaller than four is requested, read returns -1 and
199 sets errno to EINVAL. Otherwise, a four byte value is placed in
200 the data buffer, containing the current value of the fpcr regis-
201 ter.
202
203 write(2)
204 If a count smaller than four is requested, write returns -1 and
205 sets errno to EINVAL. Otherwise, a four byte value is copied
206 from the data buffer, updating the value of the fpcr register.
207
208
209 /signal1
210 /signal2
211 The two signal notification channels of an SPU. These are read-write
212 files that operate on a 32 bit word. Writing to one of these files
213 triggers an interrupt on the SPU. The value writting to the signal
214 files can be read from the SPU through a channel read or from host user
215 space through the file. After the value has been read by the SPU, it
216 is reset to zero. The possible operations on an open signal1 or sig-
217 nal2 file are:
218
219 read(2)
220 If a count smaller than four is requested, read returns -1 and
221 sets errno to EINVAL. Otherwise, a four byte value is placed in
222 the data buffer, containing the current value of the specified
223 signal notification register.
224
225 write(2)
226 If a count smaller than four is requested, write returns -1 and
227 sets errno to EINVAL. Otherwise, a four byte value is copied
228 from the data buffer, updating the value of the specified signal
229 notification register. The signal notification register will
230 either be replaced with the input data or will be updated to the
231 bitwise OR or the old value and the input data, depending on the
232 contents of the signal1_type, or signal2_type respectively,
233 file.
234
235
236 /signal1_type
237 /signal2_type
238 These two files change the behavior of the signal1 and signal2 notifi-
239 cation files. The contain a numerical ASCII string which is read as
240 either "1" or "0". In mode 0 (overwrite), the hardware replaces the
241 contents of the signal channel with the data that is written to it. in
242 mode 1 (logical OR), the hardware accumulates the bits that are subse-
243 quently written to it. The possible operations on an open signal1_type
244 or signal2_type file are:
245
246 read(2)
247 When the count supplied to the read call is shorter than the
248 required length for the digit plus a newline character, subse-
249 quent reads from the same file descriptor will result in com-
250 pleting the string. When a complete string has been read, all
251 subsequent read operations will return zero bytes and a new file
252 descriptor needs to be opened to read the value again.
253
254 write(2)
255 A write operation on the file results in setting the register to
256 the value given in the string. The string is parsed from the
257 beginning to the first non-numeric character or the end of the
258 buffer. Subsequent writes to the same file descriptor overwrite
259 the previous setting.
260
261
262EXAMPLES
263 /etc/fstab entry
264 none /spu spufs gid=spu 0 0
265
266
267AUTHORS
268 Arnd Bergmann <arndb@de.ibm.com>, Mark Nutter <mnutter@us.ibm.com>,
269 Ulrich Weigand <Ulrich.Weigand@de.ibm.com>
270
271SEE ALSO
272 capabilities(7), close(2), spu_create(2), spu_run(2), spufs(7)
273
274
275
276Linux 2005-09-28 SPUFS(2)
277
278------------------------------------------------------------------------------
279
280SPU_RUN(2) Linux Programmer's Manual SPU_RUN(2)
281
282
283
284NAME
285 spu_run - execute an spu context
286
287
288SYNOPSIS
289 #include <sys/spu.h>
290
291 int spu_run(int fd, unsigned int *npc, unsigned int *event);
292
293DESCRIPTION
294 The spu_run system call is used on PowerPC machines that implement the
295 Cell Broadband Engine Architecture in order to access Synergistic Pro-
296 cessor Units (SPUs). It uses the fd that was returned from spu_cre-
297 ate(2) to address a specific SPU context. When the context gets sched-
298 uled to a physical SPU, it starts execution at the instruction pointer
299 passed in npc.
300
301 Execution of SPU code happens synchronously, meaning that spu_run does
302 not return while the SPU is still running. If there is a need to exe-
303 cute SPU code in parallel with other code on either the main CPU or
304 other SPUs, you need to create a new thread of execution first, e.g.
305 using the pthread_create(3) call.
306
307 When spu_run returns, the current value of the SPU instruction pointer
308 is written back to npc, so you can call spu_run again without updating
309 the pointers.
310
311 event can be a NULL pointer or point to an extended status code that
312 gets filled when spu_run returns. It can be one of the following con-
313 stants:
314
315 SPE_EVENT_DMA_ALIGNMENT
316 A DMA alignment error
317
318 SPE_EVENT_SPE_DATA_SEGMENT
319 A DMA segmentation error
320
321 SPE_EVENT_SPE_DATA_STORAGE
322 A DMA storage error
323
324 If NULL is passed as the event argument, these errors will result in a
325 signal delivered to the calling process.
326
327RETURN VALUE
328 spu_run returns the value of the spu_status register or -1 to indicate
329 an error and set errno to one of the error codes listed below. The
330 spu_status register value contains a bit mask of status codes and
331 optionally a 14 bit code returned from the stop-and-signal instruction
332 on the SPU. The bit masks for the status codes are:
333
334 0x02 SPU was stopped by stop-and-signal.
335
336 0x04 SPU was stopped by halt.
337
338 0x08 SPU is waiting for a channel.
339
340 0x10 SPU is in single-step mode.
341
342 0x20 SPU has tried to execute an invalid instruction.
343
344 0x40 SPU has tried to access an invalid channel.
345
346 0x3fff0000
347 The bits masked with this value contain the code returned from
348 stop-and-signal.
349
350 There are always one or more of the lower eight bits set or an error
351 code is returned from spu_run.
352
353ERRORS
354 EAGAIN or EWOULDBLOCK
355 fd is in non-blocking mode and spu_run would block.
356
357 EBADF fd is not a valid file descriptor.
358
359 EFAULT npc is not a valid pointer or status is neither NULL nor a valid
360 pointer.
361
362 EINTR A signal occured while spu_run was in progress. The npc value
363 has been updated to the new program counter value if necessary.
364
365 EINVAL fd is not a file descriptor returned from spu_create(2).
366
367 ENOMEM Insufficient memory was available to handle a page fault result-
368 ing from an MFC direct memory access.
369
370 ENOSYS the functionality is not provided by the current system, because
371 either the hardware does not provide SPUs or the spufs module is
372 not loaded.
373
374
375NOTES
376 spu_run is meant to be used from libraries that implement a more
377 abstract interface to SPUs, not to be used from regular applications.
378 See http://www.bsc.es/projects/deepcomputing/linuxoncell/ for the rec-
379 ommended libraries.
380
381
382CONFORMING TO
383 This call is Linux specific and only implemented by the ppc64 architec-
384 ture. Programs using this system call are not portable.
385
386
387BUGS
388 The code does not yet fully implement all features lined out here.
389
390
391AUTHOR
392 Arnd Bergmann <arndb@de.ibm.com>
393
394SEE ALSO
395 capabilities(7), close(2), spu_create(2), spufs(7)
396
397
398
399Linux 2005-09-28 SPU_RUN(2)
400
401------------------------------------------------------------------------------
402
403SPU_CREATE(2) Linux Programmer's Manual SPU_CREATE(2)
404
405
406
407NAME
408 spu_create - create a new spu context
409
410
411SYNOPSIS
412 #include <sys/types.h>
413 #include <sys/spu.h>
414
415 int spu_create(const char *pathname, int flags, mode_t mode);
416
417DESCRIPTION
418 The spu_create system call is used on PowerPC machines that implement
419 the Cell Broadband Engine Architecture in order to access Synergistic
420 Processor Units (SPUs). It creates a new logical context for an SPU in
421 pathname and returns a handle to associated with it. pathname must
422 point to a non-existing directory in the mount point of the SPU file
423 system (spufs). When spu_create is successful, a directory gets cre-
424 ated on pathname and it is populated with files.
425
426 The returned file handle can only be passed to spu_run(2) or closed,
427 other operations are not defined on it. When it is closed, all associ-
428 ated directory entries in spufs are removed. When the last file handle
429 pointing either inside of the context directory or to this file
430 descriptor is closed, the logical SPU context is destroyed.
431
432 The parameter flags can be zero or any bitwise or'd combination of the
433 following constants:
434
435 SPU_RAWIO
436 Allow mapping of some of the hardware registers of the SPU into
437 user space. This flag requires the CAP_SYS_RAWIO capability, see
438 capabilities(7).
439
440 The mode parameter specifies the permissions used for creating the new
441 directory in spufs. mode is modified with the user's umask(2) value
442 and then used for both the directory and the files contained in it. The
443 file permissions mask out some more bits of mode because they typically
444 support only read or write access. See stat(2) for a full list of the
445 possible mode values.
446
447
448RETURN VALUE
449 spu_create returns a new file descriptor. It may return -1 to indicate
450 an error condition and set errno to one of the error codes listed
451 below.
452
453
454ERRORS
455 EACCESS
456 The current user does not have write access on the spufs mount
457 point.
458
459 EEXIST An SPU context already exists at the given path name.
460
461 EFAULT pathname is not a valid string pointer in the current address
462 space.
463
464 EINVAL pathname is not a directory in the spufs mount point.
465
466 ELOOP Too many symlinks were found while resolving pathname.
467
468 EMFILE The process has reached its maximum open file limit.
469
470 ENAMETOOLONG
471 pathname was too long.
472
473 ENFILE The system has reached the global open file limit.
474
475 ENOENT Part of pathname could not be resolved.
476
477 ENOMEM The kernel could not allocate all resources required.
478
479 ENOSPC There are not enough SPU resources available to create a new
480 context or the user specific limit for the number of SPU con-
481 texts has been reached.
482
483 ENOSYS the functionality is not provided by the current system, because
484 either the hardware does not provide SPUs or the spufs module is
485 not loaded.
486
487 ENOTDIR
488 A part of pathname is not a directory.
489
490
491
492NOTES
493 spu_create is meant to be used from libraries that implement a more
494 abstract interface to SPUs, not to be used from regular applications.
495 See http://www.bsc.es/projects/deepcomputing/linuxoncell/ for the rec-
496 ommended libraries.
497
498
499FILES
500 pathname must point to a location beneath the mount point of spufs. By
501 convention, it gets mounted in /spu.
502
503
504CONFORMING TO
505 This call is Linux specific and only implemented by the ppc64 architec-
506 ture. Programs using this system call are not portable.
507
508
509BUGS
510 The code does not yet fully implement all features lined out here.
511
512
513AUTHOR
514 Arnd Bergmann <arndb@de.ibm.com>
515
516SEE ALSO
517 capabilities(7), close(2), spu_run(2), spufs(7)
518
519
520
521Linux 2005-09-28 SPU_CREATE(2)
diff --git a/Documentation/filesystems/sysfs-pci.txt b/Documentation/filesystems/sysfs-pci.txt
index 988a62fae11f..7ba2baa165ff 100644
--- a/Documentation/filesystems/sysfs-pci.txt
+++ b/Documentation/filesystems/sysfs-pci.txt
@@ -1,4 +1,5 @@
1Accessing PCI device resources through sysfs 1Accessing PCI device resources through sysfs
2--------------------------------------------
2 3
3sysfs, usually mounted at /sys, provides access to PCI resources on platforms 4sysfs, usually mounted at /sys, provides access to PCI resources on platforms
4that support it. For example, a given bus might look like this: 5that support it. For example, a given bus might look like this:
@@ -47,14 +48,21 @@ files, each with their own function.
47 binary - file contains binary data 48 binary - file contains binary data
48 cpumask - file contains a cpumask type 49 cpumask - file contains a cpumask type
49 50
50The read only files are informational, writes to them will be ignored. 51The read only files are informational, writes to them will be ignored, with
51Writable files can be used to perform actions on the device (e.g. changing 52the exception of the 'rom' file. Writable files can be used to perform
52config space, detaching a device). mmapable files are available via an 53actions on the device (e.g. changing config space, detaching a device).
53mmap of the file at offset 0 and can be used to do actual device programming 54mmapable files are available via an mmap of the file at offset 0 and can be
54from userspace. Note that some platforms don't support mmapping of certain 55used to do actual device programming from userspace. Note that some platforms
55resources, so be sure to check the return value from any attempted mmap. 56don't support mmapping of certain resources, so be sure to check the return
57value from any attempted mmap.
58
59The 'rom' file is special in that it provides read-only access to the device's
60ROM file, if available. It's disabled by default, however, so applications
61should write the string "1" to the file to enable it before attempting a read
62call, and disable it following the access by writing "0" to the file.
56 63
57Accessing legacy resources through sysfs 64Accessing legacy resources through sysfs
65----------------------------------------
58 66
59Legacy I/O port and ISA memory resources are also provided in sysfs if the 67Legacy I/O port and ISA memory resources are also provided in sysfs if the
60underlying platform supports them. They're located in the PCI class heirarchy, 68underlying platform supports them. They're located in the PCI class heirarchy,
@@ -75,6 +83,7 @@ simply dereference the returned pointer (after checking for errors of course)
75to access legacy memory space. 83to access legacy memory space.
76 84
77Supporting PCI access on new platforms 85Supporting PCI access on new platforms
86--------------------------------------
78 87
79In order to support PCI resource mapping as described above, Linux platform 88In order to support PCI resource mapping as described above, Linux platform
80code must define HAVE_PCI_MMAP and provide a pci_mmap_page_range function. 89code must define HAVE_PCI_MMAP and provide a pci_mmap_page_range function.
diff --git a/Documentation/filesystems/tmpfs.txt b/Documentation/filesystems/tmpfs.txt
index 0d783c504ead..dbe4d87d2615 100644
--- a/Documentation/filesystems/tmpfs.txt
+++ b/Documentation/filesystems/tmpfs.txt
@@ -78,6 +78,18 @@ use up all the memory on the machine; but enhances the scalability of
78that instance in a system with many cpus making intensive use of it. 78that instance in a system with many cpus making intensive use of it.
79 79
80 80
81tmpfs has a mount option to set the NUMA memory allocation policy for
82all files in that instance:
83mpol=interleave prefers to allocate memory from each node in turn
84mpol=default prefers to allocate memory from the local node
85mpol=bind prefers to allocate from mpol_nodelist
86mpol=preferred prefers to allocate from first node in mpol_nodelist
87
88The following mount option is used in conjunction with mpol=interleave,
89mpol=bind or mpol=preferred:
90mpol_nodelist: nodelist suitable for parsing with nodelist_parse.
91
92
81To specify the initial root directory you can use the following mount 93To specify the initial root directory you can use the following mount
82options: 94options:
83 95
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index ee4c0a8b8db7..e56e842847d3 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -162,9 +162,8 @@ get_sb() method fills in is the "s_op" field. This is a pointer to
162a "struct super_operations" which describes the next level of the 162a "struct super_operations" which describes the next level of the
163filesystem implementation. 163filesystem implementation.
164 164
165Usually, a filesystem uses generic one of the generic get_sb() 165Usually, a filesystem uses one of the generic get_sb() implementations
166implementations and provides a fill_super() method instead. The 166and provides a fill_super() method instead. The generic methods are:
167generic methods are:
168 167
169 get_sb_bdev: mount a filesystem residing on a block device 168 get_sb_bdev: mount a filesystem residing on a block device
170 169