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authorIngo Molnar <mingo@elte.hu>2008-10-28 11:26:12 -0400
committerIngo Molnar <mingo@elte.hu>2008-10-28 11:26:12 -0400
commit7a9787e1eba95a166265e6a260cf30af04ef0a99 (patch)
treee730a4565e0318140d2fbd2f0415d18a339d7336 /Documentation/filesystems
parent41b9eb264c8407655db57b60b4457fe1b2ec9977 (diff)
parent0173a3265b228da319ceb9c1ec6a5682fd1b2d92 (diff)
Merge commit 'v2.6.28-rc2' into x86/pci-ioapic-boot-irq-quirks
Diffstat (limited to 'Documentation/filesystems')
-rw-r--r--Documentation/filesystems/Locking22
-rw-r--r--Documentation/filesystems/autofs4-mount-control.txt393
-rw-r--r--Documentation/filesystems/bfs.txt10
-rw-r--r--Documentation/filesystems/configfs/Makefile3
-rw-r--r--Documentation/filesystems/configfs/configfs.txt27
-rw-r--r--Documentation/filesystems/configfs/configfs_example_explicit.c (renamed from Documentation/filesystems/configfs/configfs_example.c)32
-rw-r--r--Documentation/filesystems/configfs/configfs_example_macros.c448
-rw-r--r--Documentation/filesystems/ext3.txt8
-rw-r--r--Documentation/filesystems/ext4.txt57
-rw-r--r--Documentation/filesystems/fiemap.txt228
-rw-r--r--Documentation/filesystems/nfs-rdma.txt103
-rw-r--r--Documentation/filesystems/nfsroot.txt2
-rw-r--r--Documentation/filesystems/ntfs.txt4
-rw-r--r--Documentation/filesystems/ocfs2.txt6
-rw-r--r--Documentation/filesystems/omfs.txt106
-rw-r--r--Documentation/filesystems/proc.txt177
-rw-r--r--Documentation/filesystems/quota.txt22
-rw-r--r--Documentation/filesystems/ramfs-rootfs-initramfs.txt2
-rw-r--r--Documentation/filesystems/relay.txt10
-rw-r--r--Documentation/filesystems/sysfs.txt6
-rw-r--r--Documentation/filesystems/ubifs.txt11
-rw-r--r--Documentation/filesystems/vfat.txt8
-rw-r--r--Documentation/filesystems/vfs.txt6
23 files changed, 1516 insertions, 175 deletions
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index 8b22d7d8b991..8362860e21a7 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -144,8 +144,8 @@ prototypes:
144 void (*kill_sb) (struct super_block *); 144 void (*kill_sb) (struct super_block *);
145locking rules: 145locking rules:
146 may block BKL 146 may block BKL
147get_sb yes yes 147get_sb yes no
148kill_sb yes yes 148kill_sb yes no
149 149
150->get_sb() returns error or 0 with locked superblock attached to the vfsmount 150->get_sb() returns error or 0 with locked superblock attached to the vfsmount
151(exclusive on ->s_umount). 151(exclusive on ->s_umount).
@@ -409,12 +409,12 @@ ioctl: yes (see below)
409unlocked_ioctl: no (see below) 409unlocked_ioctl: no (see below)
410compat_ioctl: no 410compat_ioctl: no
411mmap: no 411mmap: no
412open: maybe (see below) 412open: no
413flush: no 413flush: no
414release: no 414release: no
415fsync: no (see below) 415fsync: no (see below)
416aio_fsync: no 416aio_fsync: no
417fasync: yes (see below) 417fasync: no
418lock: yes 418lock: yes
419readv: no 419readv: no
420writev: no 420writev: no
@@ -431,13 +431,6 @@ For many filesystems, it is probably safe to acquire the inode
431semaphore. Note some filesystems (i.e. remote ones) provide no 431semaphore. Note some filesystems (i.e. remote ones) provide no
432protection for i_size so you will need to use the BKL. 432protection for i_size so you will need to use the BKL.
433 433
434->open() locking is in-transit: big lock partially moved into the methods.
435The only exception is ->open() in the instances of file_operations that never
436end up in ->i_fop/->proc_fops, i.e. ones that belong to character devices
437(chrdev_open() takes lock before replacing ->f_op and calling the secondary
438method. As soon as we fix the handling of module reference counters all
439instances of ->open() will be called without the BKL.
440
441Note: ext2_release() was *the* source of contention on fs-intensive 434Note: ext2_release() was *the* source of contention on fs-intensive
442loads and dropping BKL on ->release() helps to get rid of that (we still 435loads and dropping BKL on ->release() helps to get rid of that (we still
443grab BKL for cases when we close a file that had been opened r/w, but that 436grab BKL for cases when we close a file that had been opened r/w, but that
@@ -510,6 +503,7 @@ prototypes:
510 void (*close)(struct vm_area_struct*); 503 void (*close)(struct vm_area_struct*);
511 int (*fault)(struct vm_area_struct*, struct vm_fault *); 504 int (*fault)(struct vm_area_struct*, struct vm_fault *);
512 int (*page_mkwrite)(struct vm_area_struct *, struct page *); 505 int (*page_mkwrite)(struct vm_area_struct *, struct page *);
506 int (*access)(struct vm_area_struct *, unsigned long, void*, int, int);
513 507
514locking rules: 508locking rules:
515 BKL mmap_sem PageLocked(page) 509 BKL mmap_sem PageLocked(page)
@@ -517,6 +511,7 @@ open: no yes
517close: no yes 511close: no yes
518fault: no yes 512fault: no yes
519page_mkwrite: no yes no 513page_mkwrite: no yes no
514access: no yes
520 515
521 ->page_mkwrite() is called when a previously read-only page is 516 ->page_mkwrite() is called when a previously read-only page is
522about to become writeable. The file system is responsible for 517about to become writeable. The file system is responsible for
@@ -525,6 +520,11 @@ taking to lock out truncate, the page range should be verified to be
525within i_size. The page mapping should also be checked that it is not 520within i_size. The page mapping should also be checked that it is not
526NULL. 521NULL.
527 522
523 ->access() is called when get_user_pages() fails in
524acces_process_vm(), typically used to debug a process through
525/proc/pid/mem or ptrace. This function is needed only for
526VM_IO | VM_PFNMAP VMAs.
527
528================================================================================ 528================================================================================
529 Dubious stuff 529 Dubious stuff
530 530
diff --git a/Documentation/filesystems/autofs4-mount-control.txt b/Documentation/filesystems/autofs4-mount-control.txt
new file mode 100644
index 000000000000..c6341745df37
--- /dev/null
+++ b/Documentation/filesystems/autofs4-mount-control.txt
@@ -0,0 +1,393 @@
1
2Miscellaneous Device control operations for the autofs4 kernel module
3====================================================================
4
5The problem
6===========
7
8There is a problem with active restarts in autofs (that is to say
9restarting autofs when there are busy mounts).
10
11During normal operation autofs uses a file descriptor opened on the
12directory that is being managed in order to be able to issue control
13operations. Using a file descriptor gives ioctl operations access to
14autofs specific information stored in the super block. The operations
15are things such as setting an autofs mount catatonic, setting the
16expire timeout and requesting expire checks. As is explained below,
17certain types of autofs triggered mounts can end up covering an autofs
18mount itself which prevents us being able to use open(2) to obtain a
19file descriptor for these operations if we don't already have one open.
20
21Currently autofs uses "umount -l" (lazy umount) to clear active mounts
22at restart. While using lazy umount works for most cases, anything that
23needs to walk back up the mount tree to construct a path, such as
24getcwd(2) and the proc file system /proc/<pid>/cwd, no longer works
25because the point from which the path is constructed has been detached
26from the mount tree.
27
28The actual problem with autofs is that it can't reconnect to existing
29mounts. Immediately one thinks of just adding the ability to remount
30autofs file systems would solve it, but alas, that can't work. This is
31because autofs direct mounts and the implementation of "on demand mount
32and expire" of nested mount trees have the file system mounted directly
33on top of the mount trigger directory dentry.
34
35For example, there are two types of automount maps, direct (in the kernel
36module source you will see a third type called an offset, which is just
37a direct mount in disguise) and indirect.
38
39Here is a master map with direct and indirect map entries:
40
41/- /etc/auto.direct
42/test /etc/auto.indirect
43
44and the corresponding map files:
45
46/etc/auto.direct:
47
48/automount/dparse/g6 budgie:/autofs/export1
49/automount/dparse/g1 shark:/autofs/export1
50and so on.
51
52/etc/auto.indirect:
53
54g1 shark:/autofs/export1
55g6 budgie:/autofs/export1
56and so on.
57
58For the above indirect map an autofs file system is mounted on /test and
59mounts are triggered for each sub-directory key by the inode lookup
60operation. So we see a mount of shark:/autofs/export1 on /test/g1, for
61example.
62
63The way that direct mounts are handled is by making an autofs mount on
64each full path, such as /automount/dparse/g1, and using it as a mount
65trigger. So when we walk on the path we mount shark:/autofs/export1 "on
66top of this mount point". Since these are always directories we can
67use the follow_link inode operation to trigger the mount.
68
69But, each entry in direct and indirect maps can have offsets (making
70them multi-mount map entries).
71
72For example, an indirect mount map entry could also be:
73
74g1 \
75 / shark:/autofs/export5/testing/test \
76 /s1 shark:/autofs/export/testing/test/s1 \
77 /s2 shark:/autofs/export5/testing/test/s2 \
78 /s1/ss1 shark:/autofs/export1 \
79 /s2/ss2 shark:/autofs/export2
80
81and a similarly a direct mount map entry could also be:
82
83/automount/dparse/g1 \
84 / shark:/autofs/export5/testing/test \
85 /s1 shark:/autofs/export/testing/test/s1 \
86 /s2 shark:/autofs/export5/testing/test/s2 \
87 /s1/ss1 shark:/autofs/export2 \
88 /s2/ss2 shark:/autofs/export2
89
90One of the issues with version 4 of autofs was that, when mounting an
91entry with a large number of offsets, possibly with nesting, we needed
92to mount and umount all of the offsets as a single unit. Not really a
93problem, except for people with a large number of offsets in map entries.
94This mechanism is used for the well known "hosts" map and we have seen
95cases (in 2.4) where the available number of mounts are exhausted or
96where the number of privileged ports available is exhausted.
97
98In version 5 we mount only as we go down the tree of offsets and
99similarly for expiring them which resolves the above problem. There is
100somewhat more detail to the implementation but it isn't needed for the
101sake of the problem explanation. The one important detail is that these
102offsets are implemented using the same mechanism as the direct mounts
103above and so the mount points can be covered by a mount.
104
105The current autofs implementation uses an ioctl file descriptor opened
106on the mount point for control operations. The references held by the
107descriptor are accounted for in checks made to determine if a mount is
108in use and is also used to access autofs file system information held
109in the mount super block. So the use of a file handle needs to be
110retained.
111
112
113The Solution
114============
115
116To be able to restart autofs leaving existing direct, indirect and
117offset mounts in place we need to be able to obtain a file handle
118for these potentially covered autofs mount points. Rather than just
119implement an isolated operation it was decided to re-implement the
120existing ioctl interface and add new operations to provide this
121functionality.
122
123In addition, to be able to reconstruct a mount tree that has busy mounts,
124the uid and gid of the last user that triggered the mount needs to be
125available because these can be used as macro substitution variables in
126autofs maps. They are recorded at mount request time and an operation
127has been added to retrieve them.
128
129Since we're re-implementing the control interface, a couple of other
130problems with the existing interface have been addressed. First, when
131a mount or expire operation completes a status is returned to the
132kernel by either a "send ready" or a "send fail" operation. The
133"send fail" operation of the ioctl interface could only ever send
134ENOENT so the re-implementation allows user space to send an actual
135status. Another expensive operation in user space, for those using
136very large maps, is discovering if a mount is present. Usually this
137involves scanning /proc/mounts and since it needs to be done quite
138often it can introduce significant overhead when there are many entries
139in the mount table. An operation to lookup the mount status of a mount
140point dentry (covered or not) has also been added.
141
142Current kernel development policy recommends avoiding the use of the
143ioctl mechanism in favor of systems such as Netlink. An implementation
144using this system was attempted to evaluate its suitability and it was
145found to be inadequate, in this case. The Generic Netlink system was
146used for this as raw Netlink would lead to a significant increase in
147complexity. There's no question that the Generic Netlink system is an
148elegant solution for common case ioctl functions but it's not a complete
149replacement probably because it's primary purpose in life is to be a
150message bus implementation rather than specifically an ioctl replacement.
151While it would be possible to work around this there is one concern
152that lead to the decision to not use it. This is that the autofs
153expire in the daemon has become far to complex because umount
154candidates are enumerated, almost for no other reason than to "count"
155the number of times to call the expire ioctl. This involves scanning
156the mount table which has proved to be a big overhead for users with
157large maps. The best way to improve this is try and get back to the
158way the expire was done long ago. That is, when an expire request is
159issued for a mount (file handle) we should continually call back to
160the daemon until we can't umount any more mounts, then return the
161appropriate status to the daemon. At the moment we just expire one
162mount at a time. A Generic Netlink implementation would exclude this
163possibility for future development due to the requirements of the
164message bus architecture.
165
166
167autofs4 Miscellaneous Device mount control interface
168====================================================
169
170The control interface is opening a device node, typically /dev/autofs.
171
172All the ioctls use a common structure to pass the needed parameter
173information and return operation results:
174
175struct autofs_dev_ioctl {
176 __u32 ver_major;
177 __u32 ver_minor;
178 __u32 size; /* total size of data passed in
179 * including this struct */
180 __s32 ioctlfd; /* automount command fd */
181
182 __u32 arg1; /* Command parameters */
183 __u32 arg2;
184
185 char path[0];
186};
187
188The ioctlfd field is a mount point file descriptor of an autofs mount
189point. It is returned by the open call and is used by all calls except
190the check for whether a given path is a mount point, where it may
191optionally be used to check a specific mount corresponding to a given
192mount point file descriptor, and when requesting the uid and gid of the
193last successful mount on a directory within the autofs file system.
194
195The fields arg1 and arg2 are used to communicate parameters and results of
196calls made as described below.
197
198The path field is used to pass a path where it is needed and the size field
199is used account for the increased structure length when translating the
200structure sent from user space.
201
202This structure can be initialized before setting specific fields by using
203the void function call init_autofs_dev_ioctl(struct autofs_dev_ioctl *).
204
205All of the ioctls perform a copy of this structure from user space to
206kernel space and return -EINVAL if the size parameter is smaller than
207the structure size itself, -ENOMEM if the kernel memory allocation fails
208or -EFAULT if the copy itself fails. Other checks include a version check
209of the compiled in user space version against the module version and a
210mismatch results in a -EINVAL return. If the size field is greater than
211the structure size then a path is assumed to be present and is checked to
212ensure it begins with a "/" and is NULL terminated, otherwise -EINVAL is
213returned. Following these checks, for all ioctl commands except
214AUTOFS_DEV_IOCTL_VERSION_CMD, AUTOFS_DEV_IOCTL_OPENMOUNT_CMD and
215AUTOFS_DEV_IOCTL_CLOSEMOUNT_CMD the ioctlfd is validated and if it is
216not a valid descriptor or doesn't correspond to an autofs mount point
217an error of -EBADF, -ENOTTY or -EINVAL (not an autofs descriptor) is
218returned.
219
220
221The ioctls
222==========
223
224An example of an implementation which uses this interface can be seen
225in autofs version 5.0.4 and later in file lib/dev-ioctl-lib.c of the
226distribution tar available for download from kernel.org in directory
227/pub/linux/daemons/autofs/v5.
228
229The device node ioctl operations implemented by this interface are:
230
231
232AUTOFS_DEV_IOCTL_VERSION
233------------------------
234
235Get the major and minor version of the autofs4 device ioctl kernel module
236implementation. It requires an initialized struct autofs_dev_ioctl as an
237input parameter and sets the version information in the passed in structure.
238It returns 0 on success or the error -EINVAL if a version mismatch is
239detected.
240
241
242AUTOFS_DEV_IOCTL_PROTOVER_CMD and AUTOFS_DEV_IOCTL_PROTOSUBVER_CMD
243------------------------------------------------------------------
244
245Get the major and minor version of the autofs4 protocol version understood
246by loaded module. This call requires an initialized struct autofs_dev_ioctl
247with the ioctlfd field set to a valid autofs mount point descriptor
248and sets the requested version number in structure field arg1. These
249commands return 0 on success or one of the negative error codes if
250validation fails.
251
252
253AUTOFS_DEV_IOCTL_OPENMOUNT and AUTOFS_DEV_IOCTL_CLOSEMOUNT
254----------------------------------------------------------
255
256Obtain and release a file descriptor for an autofs managed mount point
257path. The open call requires an initialized struct autofs_dev_ioctl with
258the the path field set and the size field adjusted appropriately as well
259as the arg1 field set to the device number of the autofs mount. The
260device number can be obtained from the mount options shown in
261/proc/mounts. The close call requires an initialized struct
262autofs_dev_ioct with the ioctlfd field set to the descriptor obtained
263from the open call. The release of the file descriptor can also be done
264with close(2) so any open descriptors will also be closed at process exit.
265The close call is included in the implemented operations largely for
266completeness and to provide for a consistent user space implementation.
267
268
269AUTOFS_DEV_IOCTL_READY_CMD and AUTOFS_DEV_IOCTL_FAIL_CMD
270--------------------------------------------------------
271
272Return mount and expire result status from user space to the kernel.
273Both of these calls require an initialized struct autofs_dev_ioctl
274with the ioctlfd field set to the descriptor obtained from the open
275call and the arg1 field set to the wait queue token number, received
276by user space in the foregoing mount or expire request. The arg2 field
277is set to the status to be returned. For the ready call this is always
2780 and for the fail call it is set to the errno of the operation.
279
280
281AUTOFS_DEV_IOCTL_SETPIPEFD_CMD
282------------------------------
283
284Set the pipe file descriptor used for kernel communication to the daemon.
285Normally this is set at mount time using an option but when reconnecting
286to a existing mount we need to use this to tell the autofs mount about
287the new kernel pipe descriptor. In order to protect mounts against
288incorrectly setting the pipe descriptor we also require that the autofs
289mount be catatonic (see next call).
290
291The call requires an initialized struct autofs_dev_ioctl with the
292ioctlfd field set to the descriptor obtained from the open call and
293the arg1 field set to descriptor of the pipe. On success the call
294also sets the process group id used to identify the controlling process
295(eg. the owning automount(8) daemon) to the process group of the caller.
296
297
298AUTOFS_DEV_IOCTL_CATATONIC_CMD
299------------------------------
300
301Make the autofs mount point catatonic. The autofs mount will no longer
302issue mount requests, the kernel communication pipe descriptor is released
303and any remaining waits in the queue released.
304
305The call requires an initialized struct autofs_dev_ioctl with the
306ioctlfd field set to the descriptor obtained from the open call.
307
308
309AUTOFS_DEV_IOCTL_TIMEOUT_CMD
310----------------------------
311
312Set the expire timeout for mounts withing an autofs mount point.
313
314The call requires an initialized struct autofs_dev_ioctl with the
315ioctlfd field set to the descriptor obtained from the open call.
316
317
318AUTOFS_DEV_IOCTL_REQUESTER_CMD
319------------------------------
320
321Return the uid and gid of the last process to successfully trigger a the
322mount on the given path dentry.
323
324The call requires an initialized struct autofs_dev_ioctl with the path
325field set to the mount point in question and the size field adjusted
326appropriately as well as the arg1 field set to the device number of the
327containing autofs mount. Upon return the struct field arg1 contains the
328uid and arg2 the gid.
329
330When reconstructing an autofs mount tree with active mounts we need to
331re-connect to mounts that may have used the original process uid and
332gid (or string variations of them) for mount lookups within the map entry.
333This call provides the ability to obtain this uid and gid so they may be
334used by user space for the mount map lookups.
335
336
337AUTOFS_DEV_IOCTL_EXPIRE_CMD
338---------------------------
339
340Issue an expire request to the kernel for an autofs mount. Typically
341this ioctl is called until no further expire candidates are found.
342
343The call requires an initialized struct autofs_dev_ioctl with the
344ioctlfd field set to the descriptor obtained from the open call. In
345addition an immediate expire, independent of the mount timeout, can be
346requested by setting the arg1 field to 1. If no expire candidates can
347be found the ioctl returns -1 with errno set to EAGAIN.
348
349This call causes the kernel module to check the mount corresponding
350to the given ioctlfd for mounts that can be expired, issues an expire
351request back to the daemon and waits for completion.
352
353AUTOFS_DEV_IOCTL_ASKUMOUNT_CMD
354------------------------------
355
356Checks if an autofs mount point is in use.
357
358The call requires an initialized struct autofs_dev_ioctl with the
359ioctlfd field set to the descriptor obtained from the open call and
360it returns the result in the arg1 field, 1 for busy and 0 otherwise.
361
362
363AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD
364---------------------------------
365
366Check if the given path is a mountpoint.
367
368The call requires an initialized struct autofs_dev_ioctl. There are two
369possible variations. Both use the path field set to the path of the mount
370point to check and the size field adjusted appropriately. One uses the
371ioctlfd field to identify a specific mount point to check while the other
372variation uses the path and optionaly arg1 set to an autofs mount type.
373The call returns 1 if this is a mount point and sets arg1 to the device
374number of the mount and field arg2 to the relevant super block magic
375number (described below) or 0 if it isn't a mountpoint. In both cases
376the the device number (as returned by new_encode_dev()) is returned
377in field arg1.
378
379If supplied with a file descriptor we're looking for a specific mount,
380not necessarily at the top of the mounted stack. In this case the path
381the descriptor corresponds to is considered a mountpoint if it is itself
382a mountpoint or contains a mount, such as a multi-mount without a root
383mount. In this case we return 1 if the descriptor corresponds to a mount
384point and and also returns the super magic of the covering mount if there
385is one or 0 if it isn't a mountpoint.
386
387If a path is supplied (and the ioctlfd field is set to -1) then the path
388is looked up and is checked to see if it is the root of a mount. If a
389type is also given we are looking for a particular autofs mount and if
390a match isn't found a fail is returned. If the the located path is the
391root of a mount 1 is returned along with the super magic of the mount
392or 0 otherwise.
393
diff --git a/Documentation/filesystems/bfs.txt b/Documentation/filesystems/bfs.txt
index ea825e178e79..78043d5a8fc3 100644
--- a/Documentation/filesystems/bfs.txt
+++ b/Documentation/filesystems/bfs.txt
@@ -26,11 +26,11 @@ You can simplify mounting by just typing:
26 26
27this will allocate the first available loopback device (and load loop.o 27this will allocate the first available loopback device (and load loop.o
28kernel module if necessary) automatically. If the loopback driver is not 28kernel module if necessary) automatically. If the loopback driver is not
29loaded automatically, make sure that your kernel is compiled with kmod 29loaded automatically, make sure that you have compiled the module and
30support (CONFIG_KMOD) enabled. Beware that umount will not 30that modprobe is functioning. Beware that umount will not deallocate
31deallocate /dev/loopN device if /etc/mtab file on your system is a 31/dev/loopN device if /etc/mtab file on your system is a symbolic link to
32symbolic link to /proc/mounts. You will need to do it manually using 32/proc/mounts. You will need to do it manually using "-d" switch of
33"-d" switch of losetup(8). Read losetup(8) manpage for more info. 33losetup(8). Read losetup(8) manpage for more info.
34 34
35To create the BFS image under UnixWare you need to find out first which 35To create the BFS image under UnixWare you need to find out first which
36slice contains it. The command prtvtoc(1M) is your friend: 36slice contains it. The command prtvtoc(1M) is your friend:
diff --git a/Documentation/filesystems/configfs/Makefile b/Documentation/filesystems/configfs/Makefile
new file mode 100644
index 000000000000..be7ec5e67dbc
--- /dev/null
+++ b/Documentation/filesystems/configfs/Makefile
@@ -0,0 +1,3 @@
1ifneq ($(CONFIG_CONFIGFS_FS),)
2obj-m += configfs_example_explicit.o configfs_example_macros.o
3endif
diff --git a/Documentation/filesystems/configfs/configfs.txt b/Documentation/filesystems/configfs/configfs.txt
index 15838d706ea2..fabcb0e00f25 100644
--- a/Documentation/filesystems/configfs/configfs.txt
+++ b/Documentation/filesystems/configfs/configfs.txt
@@ -233,12 +233,10 @@ accomplished via the group operations specified on the group's
233config_item_type. 233config_item_type.
234 234
235 struct configfs_group_operations { 235 struct configfs_group_operations {
236 int (*make_item)(struct config_group *group, 236 struct config_item *(*make_item)(struct config_group *group,
237 const char *name, 237 const char *name);
238 struct config_item **new_item); 238 struct config_group *(*make_group)(struct config_group *group,
239 int (*make_group)(struct config_group *group, 239 const char *name);
240 const char *name,
241 struct config_group **new_group);
242 int (*commit_item)(struct config_item *item); 240 int (*commit_item)(struct config_item *item);
243 void (*disconnect_notify)(struct config_group *group, 241 void (*disconnect_notify)(struct config_group *group,
244 struct config_item *item); 242 struct config_item *item);
@@ -313,9 +311,20 @@ the subsystem must be ready for it.
313[An Example] 311[An Example]
314 312
315The best example of these basic concepts is the simple_children 313The best example of these basic concepts is the simple_children
316subsystem/group and the simple_child item in configfs_example.c It 314subsystem/group and the simple_child item in configfs_example_explicit.c
317shows a trivial object displaying and storing an attribute, and a simple 315and configfs_example_macros.c. It shows a trivial object displaying and
318group creating and destroying these children. 316storing an attribute, and a simple group creating and destroying these
317children.
318
319The only difference between configfs_example_explicit.c and
320configfs_example_macros.c is how the attributes of the childless item
321are defined. The childless item has extended attributes, each with
322their own show()/store() operation. This follows a convention commonly
323used in sysfs. configfs_example_explicit.c creates these attributes
324by explicitly defining the structures involved. Conversely
325configfs_example_macros.c uses some convenience macros from configfs.h
326to define the attributes. These macros are similar to their sysfs
327counterparts.
319 328
320[Hierarchy Navigation and the Subsystem Mutex] 329[Hierarchy Navigation and the Subsystem Mutex]
321 330
diff --git a/Documentation/filesystems/configfs/configfs_example.c b/Documentation/filesystems/configfs/configfs_example_explicit.c
index 0b422acd470c..d428cc9f07f3 100644
--- a/Documentation/filesystems/configfs/configfs_example.c
+++ b/Documentation/filesystems/configfs/configfs_example_explicit.c
@@ -1,8 +1,10 @@
1/* 1/*
2 * vim: noexpandtab ts=8 sts=0 sw=8: 2 * vim: noexpandtab ts=8 sts=0 sw=8:
3 * 3 *
4 * configfs_example.c - This file is a demonstration module containing 4 * configfs_example_explicit.c - This file is a demonstration module
5 * a number of configfs subsystems. 5 * containing a number of configfs subsystems. It explicitly defines
6 * each structure without using the helper macros defined in
7 * configfs.h.
6 * 8 *
7 * This program is free software; you can redistribute it and/or 9 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public 10 * modify it under the terms of the GNU General Public
@@ -273,22 +275,20 @@ static inline struct simple_children *to_simple_children(struct config_item *ite
273 return item ? container_of(to_config_group(item), struct simple_children, group) : NULL; 275 return item ? container_of(to_config_group(item), struct simple_children, group) : NULL;
274} 276}
275 277
276static int simple_children_make_item(struct config_group *group, const char *name, struct config_item **new_item) 278static struct config_item *simple_children_make_item(struct config_group *group, const char *name)
277{ 279{
278 struct simple_child *simple_child; 280 struct simple_child *simple_child;
279 281
280 simple_child = kzalloc(sizeof(struct simple_child), GFP_KERNEL); 282 simple_child = kzalloc(sizeof(struct simple_child), GFP_KERNEL);
281 if (!simple_child) 283 if (!simple_child)
282 return -ENOMEM; 284 return ERR_PTR(-ENOMEM);
283
284 285
285 config_item_init_type_name(&simple_child->item, name, 286 config_item_init_type_name(&simple_child->item, name,
286 &simple_child_type); 287 &simple_child_type);
287 288
288 simple_child->storeme = 0; 289 simple_child->storeme = 0;
289 290
290 *new_item = &simple_child->item; 291 return &simple_child->item;
291 return 0;
292} 292}
293 293
294static struct configfs_attribute simple_children_attr_description = { 294static struct configfs_attribute simple_children_attr_description = {
@@ -303,8 +303,8 @@ static struct configfs_attribute *simple_children_attrs[] = {
303}; 303};
304 304
305static ssize_t simple_children_attr_show(struct config_item *item, 305static ssize_t simple_children_attr_show(struct config_item *item,
306 struct configfs_attribute *attr, 306 struct configfs_attribute *attr,
307 char *page) 307 char *page)
308{ 308{
309 return sprintf(page, 309 return sprintf(page,
310"[02-simple-children]\n" 310"[02-simple-children]\n"
@@ -319,7 +319,7 @@ static void simple_children_release(struct config_item *item)
319} 319}
320 320
321static struct configfs_item_operations simple_children_item_ops = { 321static struct configfs_item_operations simple_children_item_ops = {
322 .release = simple_children_release, 322 .release = simple_children_release,
323 .show_attribute = simple_children_attr_show, 323 .show_attribute = simple_children_attr_show,
324}; 324};
325 325
@@ -360,21 +360,19 @@ static struct configfs_subsystem simple_children_subsys = {
360 * children of its own. 360 * children of its own.
361 */ 361 */
362 362
363static int group_children_make_group(struct config_group *group, const char *name, struct config_group **new_group) 363static struct config_group *group_children_make_group(struct config_group *group, const char *name)
364{ 364{
365 struct simple_children *simple_children; 365 struct simple_children *simple_children;
366 366
367 simple_children = kzalloc(sizeof(struct simple_children), 367 simple_children = kzalloc(sizeof(struct simple_children),
368 GFP_KERNEL); 368 GFP_KERNEL);
369 if (!simple_children) 369 if (!simple_children)
370 return -ENOMEM; 370 return ERR_PTR(-ENOMEM);
371
372 371
373 config_group_init_type_name(&simple_children->group, name, 372 config_group_init_type_name(&simple_children->group, name,
374 &simple_children_type); 373 &simple_children_type);
375 374
376 *new_group = &simple_children->group; 375 return &simple_children->group;
377 return 0;
378} 376}
379 377
380static struct configfs_attribute group_children_attr_description = { 378static struct configfs_attribute group_children_attr_description = {
@@ -389,8 +387,8 @@ static struct configfs_attribute *group_children_attrs[] = {
389}; 387};
390 388
391static ssize_t group_children_attr_show(struct config_item *item, 389static ssize_t group_children_attr_show(struct config_item *item,
392 struct configfs_attribute *attr, 390 struct configfs_attribute *attr,
393 char *page) 391 char *page)
394{ 392{
395 return sprintf(page, 393 return sprintf(page,
396"[03-group-children]\n" 394"[03-group-children]\n"
diff --git a/Documentation/filesystems/configfs/configfs_example_macros.c b/Documentation/filesystems/configfs/configfs_example_macros.c
new file mode 100644
index 000000000000..d8e30a0378aa
--- /dev/null
+++ b/Documentation/filesystems/configfs/configfs_example_macros.c
@@ -0,0 +1,448 @@
1/*
2 * vim: noexpandtab ts=8 sts=0 sw=8:
3 *
4 * configfs_example_macros.c - This file is a demonstration module
5 * containing a number of configfs subsystems. It uses the helper
6 * macros defined by configfs.h
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public
10 * License as published by the Free Software Foundation; either
11 * version 2 of the License, or (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public
19 * License along with this program; if not, write to the
20 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
21 * Boston, MA 021110-1307, USA.
22 *
23 * Based on sysfs:
24 * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
25 *
26 * configfs Copyright (C) 2005 Oracle. All rights reserved.
27 */
28
29#include <linux/init.h>
30#include <linux/module.h>
31#include <linux/slab.h>
32
33#include <linux/configfs.h>
34
35
36
37/*
38 * 01-childless
39 *
40 * This first example is a childless subsystem. It cannot create
41 * any config_items. It just has attributes.
42 *
43 * Note that we are enclosing the configfs_subsystem inside a container.
44 * This is not necessary if a subsystem has no attributes directly
45 * on the subsystem. See the next example, 02-simple-children, for
46 * such a subsystem.
47 */
48
49struct childless {
50 struct configfs_subsystem subsys;
51 int showme;
52 int storeme;
53};
54
55static inline struct childless *to_childless(struct config_item *item)
56{
57 return item ? container_of(to_configfs_subsystem(to_config_group(item)), struct childless, subsys) : NULL;
58}
59
60CONFIGFS_ATTR_STRUCT(childless);
61#define CHILDLESS_ATTR(_name, _mode, _show, _store) \
62struct childless_attribute childless_attr_##_name = __CONFIGFS_ATTR(_name, _mode, _show, _store)
63#define CHILDLESS_ATTR_RO(_name, _show) \
64struct childless_attribute childless_attr_##_name = __CONFIGFS_ATTR_RO(_name, _show);
65
66static ssize_t childless_showme_read(struct childless *childless,
67 char *page)
68{
69 ssize_t pos;
70
71 pos = sprintf(page, "%d\n", childless->showme);
72 childless->showme++;
73
74 return pos;
75}
76
77static ssize_t childless_storeme_read(struct childless *childless,
78 char *page)
79{
80 return sprintf(page, "%d\n", childless->storeme);
81}
82
83static ssize_t childless_storeme_write(struct childless *childless,
84 const char *page,
85 size_t count)
86{
87 unsigned long tmp;
88 char *p = (char *) page;
89
90 tmp = simple_strtoul(p, &p, 10);
91 if (!p || (*p && (*p != '\n')))
92 return -EINVAL;
93
94 if (tmp > INT_MAX)
95 return -ERANGE;
96
97 childless->storeme = tmp;
98
99 return count;
100}
101
102static ssize_t childless_description_read(struct childless *childless,
103 char *page)
104{
105 return sprintf(page,
106"[01-childless]\n"
107"\n"
108"The childless subsystem is the simplest possible subsystem in\n"
109"configfs. It does not support the creation of child config_items.\n"
110"It only has a few attributes. In fact, it isn't much different\n"
111"than a directory in /proc.\n");
112}
113
114CHILDLESS_ATTR_RO(showme, childless_showme_read);
115CHILDLESS_ATTR(storeme, S_IRUGO | S_IWUSR, childless_storeme_read,
116 childless_storeme_write);
117CHILDLESS_ATTR_RO(description, childless_description_read);
118
119static struct configfs_attribute *childless_attrs[] = {
120 &childless_attr_showme.attr,
121 &childless_attr_storeme.attr,
122 &childless_attr_description.attr,
123 NULL,
124};
125
126CONFIGFS_ATTR_OPS(childless);
127static struct configfs_item_operations childless_item_ops = {
128 .show_attribute = childless_attr_show,
129 .store_attribute = childless_attr_store,
130};
131
132static struct config_item_type childless_type = {
133 .ct_item_ops = &childless_item_ops,
134 .ct_attrs = childless_attrs,
135 .ct_owner = THIS_MODULE,
136};
137
138static struct childless childless_subsys = {
139 .subsys = {
140 .su_group = {
141 .cg_item = {
142 .ci_namebuf = "01-childless",
143 .ci_type = &childless_type,
144 },
145 },
146 },
147};
148
149
150/* ----------------------------------------------------------------- */
151
152/*
153 * 02-simple-children
154 *
155 * This example merely has a simple one-attribute child. Note that
156 * there is no extra attribute structure, as the child's attribute is
157 * known from the get-go. Also, there is no container for the
158 * subsystem, as it has no attributes of its own.
159 */
160
161struct simple_child {
162 struct config_item item;
163 int storeme;
164};
165
166static inline struct simple_child *to_simple_child(struct config_item *item)
167{
168 return item ? container_of(item, struct simple_child, item) : NULL;
169}
170
171static struct configfs_attribute simple_child_attr_storeme = {
172 .ca_owner = THIS_MODULE,
173 .ca_name = "storeme",
174 .ca_mode = S_IRUGO | S_IWUSR,
175};
176
177static struct configfs_attribute *simple_child_attrs[] = {
178 &simple_child_attr_storeme,
179 NULL,
180};
181
182static ssize_t simple_child_attr_show(struct config_item *item,
183 struct configfs_attribute *attr,
184 char *page)
185{
186 ssize_t count;
187 struct simple_child *simple_child = to_simple_child(item);
188
189 count = sprintf(page, "%d\n", simple_child->storeme);
190
191 return count;
192}
193
194static ssize_t simple_child_attr_store(struct config_item *item,
195 struct configfs_attribute *attr,
196 const char *page, size_t count)
197{
198 struct simple_child *simple_child = to_simple_child(item);
199 unsigned long tmp;
200 char *p = (char *) page;
201
202 tmp = simple_strtoul(p, &p, 10);
203 if (!p || (*p && (*p != '\n')))
204 return -EINVAL;
205
206 if (tmp > INT_MAX)
207 return -ERANGE;
208
209 simple_child->storeme = tmp;
210
211 return count;
212}
213
214static void simple_child_release(struct config_item *item)
215{
216 kfree(to_simple_child(item));
217}
218
219static struct configfs_item_operations simple_child_item_ops = {
220 .release = simple_child_release,
221 .show_attribute = simple_child_attr_show,
222 .store_attribute = simple_child_attr_store,
223};
224
225static struct config_item_type simple_child_type = {
226 .ct_item_ops = &simple_child_item_ops,
227 .ct_attrs = simple_child_attrs,
228 .ct_owner = THIS_MODULE,
229};
230
231
232struct simple_children {
233 struct config_group group;
234};
235
236static inline struct simple_children *to_simple_children(struct config_item *item)
237{
238 return item ? container_of(to_config_group(item), struct simple_children, group) : NULL;
239}
240
241static struct config_item *simple_children_make_item(struct config_group *group, const char *name)
242{
243 struct simple_child *simple_child;
244
245 simple_child = kzalloc(sizeof(struct simple_child), GFP_KERNEL);
246 if (!simple_child)
247 return ERR_PTR(-ENOMEM);
248
249 config_item_init_type_name(&simple_child->item, name,
250 &simple_child_type);
251
252 simple_child->storeme = 0;
253
254 return &simple_child->item;
255}
256
257static struct configfs_attribute simple_children_attr_description = {
258 .ca_owner = THIS_MODULE,
259 .ca_name = "description",
260 .ca_mode = S_IRUGO,
261};
262
263static struct configfs_attribute *simple_children_attrs[] = {
264 &simple_children_attr_description,
265 NULL,
266};
267
268static ssize_t simple_children_attr_show(struct config_item *item,
269 struct configfs_attribute *attr,
270 char *page)
271{
272 return sprintf(page,
273"[02-simple-children]\n"
274"\n"
275"This subsystem allows the creation of child config_items. These\n"
276"items have only one attribute that is readable and writeable.\n");
277}
278
279static void simple_children_release(struct config_item *item)
280{
281 kfree(to_simple_children(item));
282}
283
284static struct configfs_item_operations simple_children_item_ops = {
285 .release = simple_children_release,
286 .show_attribute = simple_children_attr_show,
287};
288
289/*
290 * Note that, since no extra work is required on ->drop_item(),
291 * no ->drop_item() is provided.
292 */
293static struct configfs_group_operations simple_children_group_ops = {
294 .make_item = simple_children_make_item,
295};
296
297static struct config_item_type simple_children_type = {
298 .ct_item_ops = &simple_children_item_ops,
299 .ct_group_ops = &simple_children_group_ops,
300 .ct_attrs = simple_children_attrs,
301 .ct_owner = THIS_MODULE,
302};
303
304static struct configfs_subsystem simple_children_subsys = {
305 .su_group = {
306 .cg_item = {
307 .ci_namebuf = "02-simple-children",
308 .ci_type = &simple_children_type,
309 },
310 },
311};
312
313
314/* ----------------------------------------------------------------- */
315
316/*
317 * 03-group-children
318 *
319 * This example reuses the simple_children group from above. However,
320 * the simple_children group is not the subsystem itself, it is a
321 * child of the subsystem. Creation of a group in the subsystem creates
322 * a new simple_children group. That group can then have simple_child
323 * children of its own.
324 */
325
326static struct config_group *group_children_make_group(struct config_group *group, const char *name)
327{
328 struct simple_children *simple_children;
329
330 simple_children = kzalloc(sizeof(struct simple_children),
331 GFP_KERNEL);
332 if (!simple_children)
333 return ERR_PTR(-ENOMEM);
334
335 config_group_init_type_name(&simple_children->group, name,
336 &simple_children_type);
337
338 return &simple_children->group;
339}
340
341static struct configfs_attribute group_children_attr_description = {
342 .ca_owner = THIS_MODULE,
343 .ca_name = "description",
344 .ca_mode = S_IRUGO,
345};
346
347static struct configfs_attribute *group_children_attrs[] = {
348 &group_children_attr_description,
349 NULL,
350};
351
352static ssize_t group_children_attr_show(struct config_item *item,
353 struct configfs_attribute *attr,
354 char *page)
355{
356 return sprintf(page,
357"[03-group-children]\n"
358"\n"
359"This subsystem allows the creation of child config_groups. These\n"
360"groups are like the subsystem simple-children.\n");
361}
362
363static struct configfs_item_operations group_children_item_ops = {
364 .show_attribute = group_children_attr_show,
365};
366
367/*
368 * Note that, since no extra work is required on ->drop_item(),
369 * no ->drop_item() is provided.
370 */
371static struct configfs_group_operations group_children_group_ops = {
372 .make_group = group_children_make_group,
373};
374
375static struct config_item_type group_children_type = {
376 .ct_item_ops = &group_children_item_ops,
377 .ct_group_ops = &group_children_group_ops,
378 .ct_attrs = group_children_attrs,
379 .ct_owner = THIS_MODULE,
380};
381
382static struct configfs_subsystem group_children_subsys = {
383 .su_group = {
384 .cg_item = {
385 .ci_namebuf = "03-group-children",
386 .ci_type = &group_children_type,
387 },
388 },
389};
390
391/* ----------------------------------------------------------------- */
392
393/*
394 * We're now done with our subsystem definitions.
395 * For convenience in this module, here's a list of them all. It
396 * allows the init function to easily register them. Most modules
397 * will only have one subsystem, and will only call register_subsystem
398 * on it directly.
399 */
400static struct configfs_subsystem *example_subsys[] = {
401 &childless_subsys.subsys,
402 &simple_children_subsys,
403 &group_children_subsys,
404 NULL,
405};
406
407static int __init configfs_example_init(void)
408{
409 int ret;
410 int i;
411 struct configfs_subsystem *subsys;
412
413 for (i = 0; example_subsys[i]; i++) {
414 subsys = example_subsys[i];
415
416 config_group_init(&subsys->su_group);
417 mutex_init(&subsys->su_mutex);
418 ret = configfs_register_subsystem(subsys);
419 if (ret) {
420 printk(KERN_ERR "Error %d while registering subsystem %s\n",
421 ret,
422 subsys->su_group.cg_item.ci_namebuf);
423 goto out_unregister;
424 }
425 }
426
427 return 0;
428
429out_unregister:
430 for (; i >= 0; i--) {
431 configfs_unregister_subsystem(example_subsys[i]);
432 }
433
434 return ret;
435}
436
437static void __exit configfs_example_exit(void)
438{
439 int i;
440
441 for (i = 0; example_subsys[i]; i++) {
442 configfs_unregister_subsystem(example_subsys[i]);
443 }
444}
445
446module_init(configfs_example_init);
447module_exit(configfs_example_exit);
448MODULE_LICENSE("GPL");
diff --git a/Documentation/filesystems/ext3.txt b/Documentation/filesystems/ext3.txt
index b45f3c1b8b43..9dd2a3bb2acc 100644
--- a/Documentation/filesystems/ext3.txt
+++ b/Documentation/filesystems/ext3.txt
@@ -96,6 +96,11 @@ errors=remount-ro(*) Remount the filesystem read-only on an error.
96errors=continue Keep going on a filesystem error. 96errors=continue Keep going on a filesystem error.
97errors=panic Panic and halt the machine if an error occurs. 97errors=panic Panic and halt the machine if an error occurs.
98 98
99data_err=ignore(*) Just print an error message if an error occurs
100 in a file data buffer in ordered mode.
101data_err=abort Abort the journal if an error occurs in a file
102 data buffer in ordered mode.
103
99grpid Give objects the same group ID as their creator. 104grpid Give objects the same group ID as their creator.
100bsdgroups 105bsdgroups
101 106
@@ -193,6 +198,5 @@ kernel source: <file:fs/ext3/>
193programs: http://e2fsprogs.sourceforge.net/ 198programs: http://e2fsprogs.sourceforge.net/
194 http://ext2resize.sourceforge.net 199 http://ext2resize.sourceforge.net
195 200
196useful links: http://www.zip.com.au/~akpm/linux/ext3/ext3-usage.html 201useful links: http://www-106.ibm.com/developerworks/linux/library/l-fs7/
197 http://www-106.ibm.com/developerworks/linux/library/l-fs7/
198 http://www-106.ibm.com/developerworks/linux/library/l-fs8/ 202 http://www-106.ibm.com/developerworks/linux/library/l-fs8/
diff --git a/Documentation/filesystems/ext4.txt b/Documentation/filesystems/ext4.txt
index 80e193d82e2e..174eaff7ded9 100644
--- a/Documentation/filesystems/ext4.txt
+++ b/Documentation/filesystems/ext4.txt
@@ -2,19 +2,24 @@
2Ext4 Filesystem 2Ext4 Filesystem
3=============== 3===============
4 4
5This is a development version of the ext4 filesystem, an advanced level 5Ext4 is an an advanced level of the ext3 filesystem which incorporates
6of the ext3 filesystem which incorporates scalability and reliability 6scalability and reliability enhancements for supporting large filesystems
7enhancements for supporting large filesystems (64 bit) in keeping with 7(64 bit) in keeping with increasing disk capacities and state-of-the-art
8increasing disk capacities and state-of-the-art feature requirements. 8feature requirements.
9 9
10Mailing list: linux-ext4@vger.kernel.org 10Mailing list: linux-ext4@vger.kernel.org
11Web site: http://ext4.wiki.kernel.org
11 12
12 13
131. Quick usage instructions: 141. Quick usage instructions:
14=========================== 15===========================
15 16
17Note: More extensive information for getting started with ext4 can be
18 found at the ext4 wiki site at the URL:
19 http://ext4.wiki.kernel.org/index.php/Ext4_Howto
20
16 - Compile and install the latest version of e2fsprogs (as of this 21 - Compile and install the latest version of e2fsprogs (as of this
17 writing version 1.41) from: 22 writing version 1.41.3) from:
18 23
19 http://sourceforge.net/project/showfiles.php?group_id=2406 24 http://sourceforge.net/project/showfiles.php?group_id=2406
20 25
@@ -26,28 +31,32 @@ Mailing list: linux-ext4@vger.kernel.org
26 31
27 git://git.kernel.org/pub/scm/fs/ext2/e2fsprogs.git 32 git://git.kernel.org/pub/scm/fs/ext2/e2fsprogs.git
28 33
29 - Create a new filesystem using the ext4dev filesystem type: 34 - Note that it is highly important to install the mke2fs.conf file
35 that comes with the e2fsprogs 1.41.x sources in /etc/mke2fs.conf. If
36 you have edited the /etc/mke2fs.conf file installed on your system,
37 you will need to merge your changes with the version from e2fsprogs
38 1.41.x.
39
40 - Create a new filesystem using the ext4 filesystem type:
30 41
31 # mke2fs -t ext4dev /dev/hda1 42 # mke2fs -t ext4 /dev/hda1
32 43
33 Or configure an existing ext3 filesystem to support extents and set 44 Or to configure an existing ext3 filesystem to support extents:
34 the test_fs flag to indicate that it's ok for an in-development
35 filesystem to touch this filesystem:
36 45
37 # tune2fs -O extents -E test_fs /dev/hda1 46 # tune2fs -O extents /dev/hda1
38 47
39 If the filesystem was created with 128 byte inodes, it can be 48 If the filesystem was created with 128 byte inodes, it can be
40 converted to use 256 byte for greater efficiency via: 49 converted to use 256 byte for greater efficiency via:
41 50
42 # tune2fs -I 256 /dev/hda1 51 # tune2fs -I 256 /dev/hda1
43 52
44 (Note: we currently do not have tools to convert an ext4dev 53 (Note: we currently do not have tools to convert an ext4
45 filesystem back to ext3; so please do not do try this on production 54 filesystem back to ext3; so please do not do try this on production
46 filesystems.) 55 filesystems.)
47 56
48 - Mounting: 57 - Mounting:
49 58
50 # mount -t ext4dev /dev/hda1 /wherever 59 # mount -t ext4 /dev/hda1 /wherever
51 60
52 - When comparing performance with other filesystems, remember that 61 - When comparing performance with other filesystems, remember that
53 ext3/4 by default offers higher data integrity guarantees than most. 62 ext3/4 by default offers higher data integrity guarantees than most.
@@ -98,8 +107,8 @@ exist yet so I'm not sure they're in the near-term roadmap.
98The big performance win will come with mballoc, delalloc and flex_bg 107The big performance win will come with mballoc, delalloc and flex_bg
99grouping of bitmaps and inode tables. Some test results available here: 108grouping of bitmaps and inode tables. Some test results available here:
100 109
101 - http://www.bullopensource.org/ext4/20080530/ffsb-write-2.6.26-rc2.html 110 - http://www.bullopensource.org/ext4/20080818-ffsb/ffsb-write-2.6.27-rc1.html
102 - http://www.bullopensource.org/ext4/20080530/ffsb-readwrite-2.6.26-rc2.html 111 - http://www.bullopensource.org/ext4/20080818-ffsb/ffsb-readwrite-2.6.27-rc1.html
103 112
1043. Options 1133. Options
105========== 114==========
@@ -171,6 +180,11 @@ barrier=<0|1(*)> This enables/disables the use of write barriers in
171 your disks are battery-backed in one way or another, 180 your disks are battery-backed in one way or another,
172 disabling barriers may safely improve performance. 181 disabling barriers may safely improve performance.
173 182
183inode_readahead=n This tuning parameter controls the maximum
184 number of inode table blocks that ext4's inode
185 table readahead algorithm will pre-read into
186 the buffer cache. The default value is 32 blocks.
187
174orlov (*) This enables the new Orlov block allocator. It is 188orlov (*) This enables the new Orlov block allocator. It is
175 enabled by default. 189 enabled by default.
176 190
@@ -203,15 +217,17 @@ noreservation
203bsddf (*) Make 'df' act like BSD. 217bsddf (*) Make 'df' act like BSD.
204minixdf Make 'df' act like Minix. 218minixdf Make 'df' act like Minix.
205 219
206check=none Don't do extra checking of bitmaps on mount.
207nocheck
208
209debug Extra debugging information is sent to syslog. 220debug Extra debugging information is sent to syslog.
210 221
211errors=remount-ro(*) Remount the filesystem read-only on an error. 222errors=remount-ro(*) Remount the filesystem read-only on an error.
212errors=continue Keep going on a filesystem error. 223errors=continue Keep going on a filesystem error.
213errors=panic Panic and halt the machine if an error occurs. 224errors=panic Panic and halt the machine if an error occurs.
214 225
226data_err=ignore(*) Just print an error message if an error occurs
227 in a file data buffer in ordered mode.
228data_err=abort Abort the journal if an error occurs in a file
229 data buffer in ordered mode.
230
215grpid Give objects the same group ID as their creator. 231grpid Give objects the same group ID as their creator.
216bsdgroups 232bsdgroups
217 233
@@ -237,8 +253,6 @@ nobh (a) cache disk block mapping information
237 "nobh" option tries to avoid associating buffer 253 "nobh" option tries to avoid associating buffer
238 heads (supported only for "writeback" mode). 254 heads (supported only for "writeback" mode).
239 255
240mballoc (*) Use the multiple block allocator for block allocation
241nomballoc disabled multiple block allocator for block allocation.
242stripe=n Number of filesystem blocks that mballoc will try 256stripe=n Number of filesystem blocks that mballoc will try
243 to use for allocation size and alignment. For RAID5/6 257 to use for allocation size and alignment. For RAID5/6
244 systems this should be the number of data 258 systems this should be the number of data
@@ -246,6 +260,7 @@ stripe=n Number of filesystem blocks that mballoc will try
246delalloc (*) Deferring block allocation until write-out time. 260delalloc (*) Deferring block allocation until write-out time.
247nodelalloc Disable delayed allocation. Blocks are allocation 261nodelalloc Disable delayed allocation. Blocks are allocation
248 when data is copied from user to page cache. 262 when data is copied from user to page cache.
263
249Data Mode 264Data Mode
250========= 265=========
251There are 3 different data modes: 266There are 3 different data modes:
diff --git a/Documentation/filesystems/fiemap.txt b/Documentation/filesystems/fiemap.txt
new file mode 100644
index 000000000000..1e3defcfe50b
--- /dev/null
+++ b/Documentation/filesystems/fiemap.txt
@@ -0,0 +1,228 @@
1============
2Fiemap Ioctl
3============
4
5The fiemap ioctl is an efficient method for userspace to get file
6extent mappings. Instead of block-by-block mapping (such as bmap), fiemap
7returns a list of extents.
8
9
10Request Basics
11--------------
12
13A fiemap request is encoded within struct fiemap:
14
15struct fiemap {
16 __u64 fm_start; /* logical offset (inclusive) at
17 * which to start mapping (in) */
18 __u64 fm_length; /* logical length of mapping which
19 * userspace cares about (in) */
20 __u32 fm_flags; /* FIEMAP_FLAG_* flags for request (in/out) */
21 __u32 fm_mapped_extents; /* number of extents that were
22 * mapped (out) */
23 __u32 fm_extent_count; /* size of fm_extents array (in) */
24 __u32 fm_reserved;
25 struct fiemap_extent fm_extents[0]; /* array of mapped extents (out) */
26};
27
28
29fm_start, and fm_length specify the logical range within the file
30which the process would like mappings for. Extents returned mirror
31those on disk - that is, the logical offset of the 1st returned extent
32may start before fm_start, and the range covered by the last returned
33extent may end after fm_length. All offsets and lengths are in bytes.
34
35Certain flags to modify the way in which mappings are looked up can be
36set in fm_flags. If the kernel doesn't understand some particular
37flags, it will return EBADR and the contents of fm_flags will contain
38the set of flags which caused the error. If the kernel is compatible
39with all flags passed, the contents of fm_flags will be unmodified.
40It is up to userspace to determine whether rejection of a particular
41flag is fatal to it's operation. This scheme is intended to allow the
42fiemap interface to grow in the future but without losing
43compatibility with old software.
44
45fm_extent_count specifies the number of elements in the fm_extents[] array
46that can be used to return extents. If fm_extent_count is zero, then the
47fm_extents[] array is ignored (no extents will be returned), and the
48fm_mapped_extents count will hold the number of extents needed in
49fm_extents[] to hold the file's current mapping. Note that there is
50nothing to prevent the file from changing between calls to FIEMAP.
51
52The following flags can be set in fm_flags:
53
54* FIEMAP_FLAG_SYNC
55If this flag is set, the kernel will sync the file before mapping extents.
56
57* FIEMAP_FLAG_XATTR
58If this flag is set, the extents returned will describe the inodes
59extended attribute lookup tree, instead of it's data tree.
60
61
62Extent Mapping
63--------------
64
65Extent information is returned within the embedded fm_extents array
66which userspace must allocate along with the fiemap structure. The
67number of elements in the fiemap_extents[] array should be passed via
68fm_extent_count. The number of extents mapped by kernel will be
69returned via fm_mapped_extents. If the number of fiemap_extents
70allocated is less than would be required to map the requested range,
71the maximum number of extents that can be mapped in the fm_extent[]
72array will be returned and fm_mapped_extents will be equal to
73fm_extent_count. In that case, the last extent in the array will not
74complete the requested range and will not have the FIEMAP_EXTENT_LAST
75flag set (see the next section on extent flags).
76
77Each extent is described by a single fiemap_extent structure as
78returned in fm_extents.
79
80struct fiemap_extent {
81 __u64 fe_logical; /* logical offset in bytes for the start of
82 * the extent */
83 __u64 fe_physical; /* physical offset in bytes for the start
84 * of the extent */
85 __u64 fe_length; /* length in bytes for the extent */
86 __u64 fe_reserved64[2];
87 __u32 fe_flags; /* FIEMAP_EXTENT_* flags for this extent */
88 __u32 fe_reserved[3];
89};
90
91All offsets and lengths are in bytes and mirror those on disk. It is valid
92for an extents logical offset to start before the request or it's logical
93length to extend past the request. Unless FIEMAP_EXTENT_NOT_ALIGNED is
94returned, fe_logical, fe_physical, and fe_length will be aligned to the
95block size of the file system. With the exception of extents flagged as
96FIEMAP_EXTENT_MERGED, adjacent extents will not be merged.
97
98The fe_flags field contains flags which describe the extent returned.
99A special flag, FIEMAP_EXTENT_LAST is always set on the last extent in
100the file so that the process making fiemap calls can determine when no
101more extents are available, without having to call the ioctl again.
102
103Some flags are intentionally vague and will always be set in the
104presence of other more specific flags. This way a program looking for
105a general property does not have to know all existing and future flags
106which imply that property.
107
108For example, if FIEMAP_EXTENT_DATA_INLINE or FIEMAP_EXTENT_DATA_TAIL
109are set, FIEMAP_EXTENT_NOT_ALIGNED will also be set. A program looking
110for inline or tail-packed data can key on the specific flag. Software
111which simply cares not to try operating on non-aligned extents
112however, can just key on FIEMAP_EXTENT_NOT_ALIGNED, and not have to
113worry about all present and future flags which might imply unaligned
114data. Note that the opposite is not true - it would be valid for
115FIEMAP_EXTENT_NOT_ALIGNED to appear alone.
116
117* FIEMAP_EXTENT_LAST
118This is the last extent in the file. A mapping attempt past this
119extent will return nothing.
120
121* FIEMAP_EXTENT_UNKNOWN
122The location of this extent is currently unknown. This may indicate
123the data is stored on an inaccessible volume or that no storage has
124been allocated for the file yet.
125
126* FIEMAP_EXTENT_DELALLOC
127 - This will also set FIEMAP_EXTENT_UNKNOWN.
128Delayed allocation - while there is data for this extent, it's
129physical location has not been allocated yet.
130
131* FIEMAP_EXTENT_ENCODED
132This extent does not consist of plain filesystem blocks but is
133encoded (e.g. encrypted or compressed). Reading the data in this
134extent via I/O to the block device will have undefined results.
135
136Note that it is *always* undefined to try to update the data
137in-place by writing to the indicated location without the
138assistance of the filesystem, or to access the data using the
139information returned by the FIEMAP interface while the filesystem
140is mounted. In other words, user applications may only read the
141extent data via I/O to the block device while the filesystem is
142unmounted, and then only if the FIEMAP_EXTENT_ENCODED flag is
143clear; user applications must not try reading or writing to the
144filesystem via the block device under any other circumstances.
145
146* FIEMAP_EXTENT_DATA_ENCRYPTED
147 - This will also set FIEMAP_EXTENT_ENCODED
148The data in this extent has been encrypted by the file system.
149
150* FIEMAP_EXTENT_NOT_ALIGNED
151Extent offsets and length are not guaranteed to be block aligned.
152
153* FIEMAP_EXTENT_DATA_INLINE
154 This will also set FIEMAP_EXTENT_NOT_ALIGNED
155Data is located within a meta data block.
156
157* FIEMAP_EXTENT_DATA_TAIL
158 This will also set FIEMAP_EXTENT_NOT_ALIGNED
159Data is packed into a block with data from other files.
160
161* FIEMAP_EXTENT_UNWRITTEN
162Unwritten extent - the extent is allocated but it's data has not been
163initialized. This indicates the extent's data will be all zero if read
164through the filesystem but the contents are undefined if read directly from
165the device.
166
167* FIEMAP_EXTENT_MERGED
168This will be set when a file does not support extents, i.e., it uses a block
169based addressing scheme. Since returning an extent for each block back to
170userspace would be highly inefficient, the kernel will try to merge most
171adjacent blocks into 'extents'.
172
173
174VFS -> File System Implementation
175---------------------------------
176
177File systems wishing to support fiemap must implement a ->fiemap callback on
178their inode_operations structure. The fs ->fiemap call is responsible for
179defining it's set of supported fiemap flags, and calling a helper function on
180each discovered extent:
181
182struct inode_operations {
183 ...
184
185 int (*fiemap)(struct inode *, struct fiemap_extent_info *, u64 start,
186 u64 len);
187
188->fiemap is passed struct fiemap_extent_info which describes the
189fiemap request:
190
191struct fiemap_extent_info {
192 unsigned int fi_flags; /* Flags as passed from user */
193 unsigned int fi_extents_mapped; /* Number of mapped extents */
194 unsigned int fi_extents_max; /* Size of fiemap_extent array */
195 struct fiemap_extent *fi_extents_start; /* Start of fiemap_extent array */
196};
197
198It is intended that the file system should not need to access any of this
199structure directly.
200
201
202Flag checking should be done at the beginning of the ->fiemap callback via the
203fiemap_check_flags() helper:
204
205int fiemap_check_flags(struct fiemap_extent_info *fieinfo, u32 fs_flags);
206
207The struct fieinfo should be passed in as recieved from ioctl_fiemap(). The
208set of fiemap flags which the fs understands should be passed via fs_flags. If
209fiemap_check_flags finds invalid user flags, it will place the bad values in
210fieinfo->fi_flags and return -EBADR. If the file system gets -EBADR, from
211fiemap_check_flags(), it should immediately exit, returning that error back to
212ioctl_fiemap().
213
214
215For each extent in the request range, the file system should call
216the helper function, fiemap_fill_next_extent():
217
218int fiemap_fill_next_extent(struct fiemap_extent_info *info, u64 logical,
219 u64 phys, u64 len, u32 flags, u32 dev);
220
221fiemap_fill_next_extent() will use the passed values to populate the
222next free extent in the fm_extents array. 'General' extent flags will
223automatically be set from specific flags on behalf of the calling file
224system so that the userspace API is not broken.
225
226fiemap_fill_next_extent() returns 0 on success, and 1 when the
227user-supplied fm_extents array is full. If an error is encountered
228while copying the extent to user memory, -EFAULT will be returned.
diff --git a/Documentation/filesystems/nfs-rdma.txt b/Documentation/filesystems/nfs-rdma.txt
index d0ec45ae4e7d..44bd766f2e5d 100644
--- a/Documentation/filesystems/nfs-rdma.txt
+++ b/Documentation/filesystems/nfs-rdma.txt
@@ -5,7 +5,7 @@
5################################################################################ 5################################################################################
6 6
7 Author: NetApp and Open Grid Computing 7 Author: NetApp and Open Grid Computing
8 Date: April 15, 2008 8 Date: May 29, 2008
9 9
10Table of Contents 10Table of Contents
11~~~~~~~~~~~~~~~~~ 11~~~~~~~~~~~~~~~~~
@@ -60,16 +60,18 @@ Installation
60 The procedures described in this document have been tested with 60 The procedures described in this document have been tested with
61 distributions from Red Hat's Fedora Project (http://fedora.redhat.com/). 61 distributions from Red Hat's Fedora Project (http://fedora.redhat.com/).
62 62
63 - Install nfs-utils-1.1.1 or greater on the client 63 - Install nfs-utils-1.1.2 or greater on the client
64 64
65 An NFS/RDMA mount point can only be obtained by using the mount.nfs 65 An NFS/RDMA mount point can be obtained by using the mount.nfs command in
66 command in nfs-utils-1.1.1 or greater. To see which version of mount.nfs 66 nfs-utils-1.1.2 or greater (nfs-utils-1.1.1 was the first nfs-utils
67 you are using, type: 67 version with support for NFS/RDMA mounts, but for various reasons we
68 recommend using nfs-utils-1.1.2 or greater). To see which version of
69 mount.nfs you are using, type:
68 70
69 > /sbin/mount.nfs -V 71 $ /sbin/mount.nfs -V
70 72
71 If the version is less than 1.1.1 or the command does not exist, 73 If the version is less than 1.1.2 or the command does not exist,
72 then you will need to install the latest version of nfs-utils. 74 you should install the latest version of nfs-utils.
73 75
74 Download the latest package from: 76 Download the latest package from:
75 77
@@ -77,22 +79,33 @@ Installation
77 79
78 Uncompress the package and follow the installation instructions. 80 Uncompress the package and follow the installation instructions.
79 81
80 If you will not be using GSS and NFSv4, the installation process 82 If you will not need the idmapper and gssd executables (you do not need
81 can be simplified by disabling these features when running configure: 83 these to create an NFS/RDMA enabled mount command), the installation
84 process can be simplified by disabling these features when running
85 configure:
82 86
83 > ./configure --disable-gss --disable-nfsv4 87 $ ./configure --disable-gss --disable-nfsv4
84 88
85 For more information on this see the package's README and INSTALL files. 89 To build nfs-utils you will need the tcp_wrappers package installed. For
90 more information on this see the package's README and INSTALL files.
86 91
87 After building the nfs-utils package, there will be a mount.nfs binary in 92 After building the nfs-utils package, there will be a mount.nfs binary in
88 the utils/mount directory. This binary can be used to initiate NFS v2, v3, 93 the utils/mount directory. This binary can be used to initiate NFS v2, v3,
89 or v4 mounts. To initiate a v4 mount, the binary must be called mount.nfs4. 94 or v4 mounts. To initiate a v4 mount, the binary must be called
90 The standard technique is to create a symlink called mount.nfs4 to mount.nfs. 95 mount.nfs4. The standard technique is to create a symlink called
96 mount.nfs4 to mount.nfs.
91 97
92 NOTE: mount.nfs and therefore nfs-utils-1.1.1 or greater is only needed 98 This mount.nfs binary should be installed at /sbin/mount.nfs as follows:
99
100 $ sudo cp utils/mount/mount.nfs /sbin/mount.nfs
101
102 In this location, mount.nfs will be invoked automatically for NFS mounts
103 by the system mount commmand.
104
105 NOTE: mount.nfs and therefore nfs-utils-1.1.2 or greater is only needed
93 on the NFS client machine. You do not need this specific version of 106 on the NFS client machine. You do not need this specific version of
94 nfs-utils on the server. Furthermore, only the mount.nfs command from 107 nfs-utils on the server. Furthermore, only the mount.nfs command from
95 nfs-utils-1.1.1 is needed on the client. 108 nfs-utils-1.1.2 is needed on the client.
96 109
97 - Install a Linux kernel with NFS/RDMA 110 - Install a Linux kernel with NFS/RDMA
98 111
@@ -156,8 +169,8 @@ Check RDMA and NFS Setup
156 this time. For example, if you are using a Mellanox Tavor/Sinai/Arbel 169 this time. For example, if you are using a Mellanox Tavor/Sinai/Arbel
157 card: 170 card:
158 171
159 > modprobe ib_mthca 172 $ modprobe ib_mthca
160 > modprobe ib_ipoib 173 $ modprobe ib_ipoib
161 174
162 If you are using InfiniBand, make sure there is a Subnet Manager (SM) 175 If you are using InfiniBand, make sure there is a Subnet Manager (SM)
163 running on the network. If your IB switch has an embedded SM, you can 176 running on the network. If your IB switch has an embedded SM, you can
@@ -166,7 +179,7 @@ Check RDMA and NFS Setup
166 179
167 If an SM is running on your network, you should see the following: 180 If an SM is running on your network, you should see the following:
168 181
169 > cat /sys/class/infiniband/driverX/ports/1/state 182 $ cat /sys/class/infiniband/driverX/ports/1/state
170 4: ACTIVE 183 4: ACTIVE
171 184
172 where driverX is mthca0, ipath5, ehca3, etc. 185 where driverX is mthca0, ipath5, ehca3, etc.
@@ -174,10 +187,10 @@ Check RDMA and NFS Setup
174 To further test the InfiniBand software stack, use IPoIB (this 187 To further test the InfiniBand software stack, use IPoIB (this
175 assumes you have two IB hosts named host1 and host2): 188 assumes you have two IB hosts named host1 and host2):
176 189
177 host1> ifconfig ib0 a.b.c.x 190 host1$ ifconfig ib0 a.b.c.x
178 host2> ifconfig ib0 a.b.c.y 191 host2$ ifconfig ib0 a.b.c.y
179 host1> ping a.b.c.y 192 host1$ ping a.b.c.y
180 host2> ping a.b.c.x 193 host2$ ping a.b.c.x
181 194
182 For other device types, follow the appropriate procedures. 195 For other device types, follow the appropriate procedures.
183 196
@@ -202,11 +215,11 @@ NFS/RDMA Setup
202 /vol0 192.168.0.47(fsid=0,rw,async,insecure,no_root_squash) 215 /vol0 192.168.0.47(fsid=0,rw,async,insecure,no_root_squash)
203 /vol0 192.168.0.0/255.255.255.0(fsid=0,rw,async,insecure,no_root_squash) 216 /vol0 192.168.0.0/255.255.255.0(fsid=0,rw,async,insecure,no_root_squash)
204 217
205 The IP address(es) is(are) the client's IPoIB address for an InfiniBand HCA or the 218 The IP address(es) is(are) the client's IPoIB address for an InfiniBand
206 cleint's iWARP address(es) for an RNIC. 219 HCA or the cleint's iWARP address(es) for an RNIC.
207 220
208 NOTE: The "insecure" option must be used because the NFS/RDMA client does not 221 NOTE: The "insecure" option must be used because the NFS/RDMA client does
209 use a reserved port. 222 not use a reserved port.
210 223
211 Each time a machine boots: 224 Each time a machine boots:
212 225
@@ -214,43 +227,45 @@ NFS/RDMA Setup
214 227
215 For InfiniBand using a Mellanox adapter: 228 For InfiniBand using a Mellanox adapter:
216 229
217 > modprobe ib_mthca 230 $ modprobe ib_mthca
218 > modprobe ib_ipoib 231 $ modprobe ib_ipoib
219 > ifconfig ib0 a.b.c.d 232 $ ifconfig ib0 a.b.c.d
220 233
221 NOTE: use unique addresses for the client and server 234 NOTE: use unique addresses for the client and server
222 235
223 - Start the NFS server 236 - Start the NFS server
224 237
225 If the NFS/RDMA server was built as a module (CONFIG_SUNRPC_XPRT_RDMA=m in kernel config), 238 If the NFS/RDMA server was built as a module (CONFIG_SUNRPC_XPRT_RDMA=m in
226 load the RDMA transport module: 239 kernel config), load the RDMA transport module:
227 240
228 > modprobe svcrdma 241 $ modprobe svcrdma
229 242
230 Regardless of how the server was built (module or built-in), start the server: 243 Regardless of how the server was built (module or built-in), start the
244 server:
231 245
232 > /etc/init.d/nfs start 246 $ /etc/init.d/nfs start
233 247
234 or 248 or
235 249
236 > service nfs start 250 $ service nfs start
237 251
238 Instruct the server to listen on the RDMA transport: 252 Instruct the server to listen on the RDMA transport:
239 253
240 > echo rdma 2050 > /proc/fs/nfsd/portlist 254 $ echo rdma 2050 > /proc/fs/nfsd/portlist
241 255
242 - On the client system 256 - On the client system
243 257
244 If the NFS/RDMA client was built as a module (CONFIG_SUNRPC_XPRT_RDMA=m in kernel config), 258 If the NFS/RDMA client was built as a module (CONFIG_SUNRPC_XPRT_RDMA=m in
245 load the RDMA client module: 259 kernel config), load the RDMA client module:
246 260
247 > modprobe xprtrdma.ko 261 $ modprobe xprtrdma.ko
248 262
249 Regardless of how the client was built (module or built-in), issue the mount.nfs command: 263 Regardless of how the client was built (module or built-in), use this
264 command to mount the NFS/RDMA server:
250 265
251 > /path/to/your/mount.nfs <IPoIB-server-name-or-address>:/<export> /mnt -i -o rdma,port=2050 266 $ mount -o rdma,port=2050 <IPoIB-server-name-or-address>:/<export> /mnt
252 267
253 To verify that the mount is using RDMA, run "cat /proc/mounts" and check the 268 To verify that the mount is using RDMA, run "cat /proc/mounts" and check
254 "proto" field for the given mount. 269 the "proto" field for the given mount.
255 270
256 Congratulations! You're using NFS/RDMA! 271 Congratulations! You're using NFS/RDMA!
diff --git a/Documentation/filesystems/nfsroot.txt b/Documentation/filesystems/nfsroot.txt
index 31b329172343..68baddf3c3e0 100644
--- a/Documentation/filesystems/nfsroot.txt
+++ b/Documentation/filesystems/nfsroot.txt
@@ -169,7 +169,7 @@ They depend on various facilities being available:
1693.1) Booting from a floppy using syslinux 1693.1) Booting from a floppy using syslinux
170 170
171 When building kernels, an easy way to create a boot floppy that uses 171 When building kernels, an easy way to create a boot floppy that uses
172 syslinux is to use the zdisk or bzdisk make targets which use 172 syslinux is to use the zdisk or bzdisk make targets which use zimage
173 and bzimage images respectively. Both targets accept the 173 and bzimage images respectively. Both targets accept the
174 FDARGS parameter which can be used to set the kernel command line. 174 FDARGS parameter which can be used to set the kernel command line.
175 175
diff --git a/Documentation/filesystems/ntfs.txt b/Documentation/filesystems/ntfs.txt
index e79ee2db183a..ac2a261c5f7d 100644
--- a/Documentation/filesystems/ntfs.txt
+++ b/Documentation/filesystems/ntfs.txt
@@ -40,7 +40,7 @@ Web site
40======== 40========
41 41
42There is plenty of additional information on the linux-ntfs web site 42There is plenty of additional information on the linux-ntfs web site
43at http://linux-ntfs.sourceforge.net/ 43at http://www.linux-ntfs.org/
44 44
45The web site has a lot of additional information, such as a comprehensive 45The web site has a lot of additional information, such as a comprehensive
46FAQ, documentation on the NTFS on-disk format, information on the Linux-NTFS 46FAQ, documentation on the NTFS on-disk format, information on the Linux-NTFS
@@ -272,7 +272,7 @@ And you would know that /dev/hda2 has a size of 37768814 - 4209030 + 1 =
272For Win2k and later dynamic disks, you can for example use the ldminfo utility 272For Win2k and later dynamic disks, you can for example use the ldminfo utility
273which is part of the Linux LDM tools (the latest version at the time of 273which is part of the Linux LDM tools (the latest version at the time of
274writing is linux-ldm-0.0.8.tar.bz2). You can download it from: 274writing is linux-ldm-0.0.8.tar.bz2). You can download it from:
275 http://linux-ntfs.sourceforge.net/downloads.html 275 http://www.linux-ntfs.org/
276Simply extract the downloaded archive (tar xvjf linux-ldm-0.0.8.tar.bz2), go 276Simply extract the downloaded archive (tar xvjf linux-ldm-0.0.8.tar.bz2), go
277into it (cd linux-ldm-0.0.8) and change to the test directory (cd test). You 277into it (cd linux-ldm-0.0.8) and change to the test directory (cd test). You
278will find the precompiled (i386) ldminfo utility there. NOTE: You will not be 278will find the precompiled (i386) ldminfo utility there. NOTE: You will not be
diff --git a/Documentation/filesystems/ocfs2.txt b/Documentation/filesystems/ocfs2.txt
index c318a8bbb1ef..4340cc825796 100644
--- a/Documentation/filesystems/ocfs2.txt
+++ b/Documentation/filesystems/ocfs2.txt
@@ -76,3 +76,9 @@ localalloc=8(*) Allows custom localalloc size in MB. If the value is too
76 large, the fs will silently revert it to the default. 76 large, the fs will silently revert it to the default.
77 Localalloc is not enabled for local mounts. 77 Localalloc is not enabled for local mounts.
78localflocks This disables cluster aware flock. 78localflocks This disables cluster aware flock.
79inode64 Indicates that Ocfs2 is allowed to create inodes at
80 any location in the filesystem, including those which
81 will result in inode numbers occupying more than 32
82 bits of significance.
83user_xattr (*) Enables Extended User Attributes.
84nouser_xattr Disables Extended User Attributes.
diff --git a/Documentation/filesystems/omfs.txt b/Documentation/filesystems/omfs.txt
new file mode 100644
index 000000000000..1d0d41ff5c65
--- /dev/null
+++ b/Documentation/filesystems/omfs.txt
@@ -0,0 +1,106 @@
1Optimized MPEG Filesystem (OMFS)
2
3Overview
4========
5
6OMFS is a filesystem created by SonicBlue for use in the ReplayTV DVR
7and Rio Karma MP3 player. The filesystem is extent-based, utilizing
8block sizes from 2k to 8k, with hash-based directories. This
9filesystem driver may be used to read and write disks from these
10devices.
11
12Note, it is not recommended that this FS be used in place of a general
13filesystem for your own streaming media device. Native Linux filesystems
14will likely perform better.
15
16More information is available at:
17
18 http://linux-karma.sf.net/
19
20Various utilities, including mkomfs and omfsck, are included with
21omfsprogs, available at:
22
23 http://bobcopeland.com/karma/
24
25Instructions are included in its README.
26
27Options
28=======
29
30OMFS supports the following mount-time options:
31
32 uid=n - make all files owned by specified user
33 gid=n - make all files owned by specified group
34 umask=xxx - set permission umask to xxx
35 fmask=xxx - set umask to xxx for files
36 dmask=xxx - set umask to xxx for directories
37
38Disk format
39===========
40
41OMFS discriminates between "sysblocks" and normal data blocks. The sysblock
42group consists of super block information, file metadata, directory structures,
43and extents. Each sysblock has a header containing CRCs of the entire
44sysblock, and may be mirrored in successive blocks on the disk. A sysblock may
45have a smaller size than a data block, but since they are both addressed by the
46same 64-bit block number, any remaining space in the smaller sysblock is
47unused.
48
49Sysblock header information:
50
51struct omfs_header {
52 __be64 h_self; /* FS block where this is located */
53 __be32 h_body_size; /* size of useful data after header */
54 __be16 h_crc; /* crc-ccitt of body_size bytes */
55 char h_fill1[2];
56 u8 h_version; /* version, always 1 */
57 char h_type; /* OMFS_INODE_X */
58 u8 h_magic; /* OMFS_IMAGIC */
59 u8 h_check_xor; /* XOR of header bytes before this */
60 __be32 h_fill2;
61};
62
63Files and directories are both represented by omfs_inode:
64
65struct omfs_inode {
66 struct omfs_header i_head; /* header */
67 __be64 i_parent; /* parent containing this inode */
68 __be64 i_sibling; /* next inode in hash bucket */
69 __be64 i_ctime; /* ctime, in milliseconds */
70 char i_fill1[35];
71 char i_type; /* OMFS_[DIR,FILE] */
72 __be32 i_fill2;
73 char i_fill3[64];
74 char i_name[OMFS_NAMELEN]; /* filename */
75 __be64 i_size; /* size of file, in bytes */
76};
77
78Directories in OMFS are implemented as a large hash table. Filenames are
79hashed then prepended into the bucket list beginning at OMFS_DIR_START.
80Lookup requires hashing the filename, then seeking across i_sibling pointers
81until a match is found on i_name. Empty buckets are represented by block
82pointers with all-1s (~0).
83
84A file is an omfs_inode structure followed by an extent table beginning at
85OMFS_EXTENT_START:
86
87struct omfs_extent_entry {
88 __be64 e_cluster; /* start location of a set of blocks */
89 __be64 e_blocks; /* number of blocks after e_cluster */
90};
91
92struct omfs_extent {
93 __be64 e_next; /* next extent table location */
94 __be32 e_extent_count; /* total # extents in this table */
95 __be32 e_fill;
96 struct omfs_extent_entry e_entry; /* start of extent entries */
97};
98
99Each extent holds the block offset followed by number of blocks allocated to
100the extent. The final extent in each table is a terminator with e_cluster
101being ~0 and e_blocks being ones'-complement of the total number of blocks
102in the table.
103
104If this table overflows, a continuation inode is written and pointed to by
105e_next. These have a header but lack the rest of the inode structure.
106
diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index 7f268f327d75..bcceb99b81dd 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -296,6 +296,7 @@ Table 1-4: Kernel info in /proc
296 uptime System uptime 296 uptime System uptime
297 version Kernel version 297 version Kernel version
298 video bttv info of video resources (2.4) 298 video bttv info of video resources (2.4)
299 vmallocinfo Show vmalloced areas
299.............................................................................. 300..............................................................................
300 301
301You can, for example, check which interrupts are currently in use and what 302You can, for example, check which interrupts are currently in use and what
@@ -557,6 +558,49 @@ VmallocTotal: total size of vmalloc memory area
557 VmallocUsed: amount of vmalloc area which is used 558 VmallocUsed: amount of vmalloc area which is used
558VmallocChunk: largest contigious block of vmalloc area which is free 559VmallocChunk: largest contigious block of vmalloc area which is free
559 560
561..............................................................................
562
563vmallocinfo:
564
565Provides information about vmalloced/vmaped areas. One line per area,
566containing the virtual address range of the area, size in bytes,
567caller information of the creator, and optional information depending
568on the kind of area :
569
570 pages=nr number of pages
571 phys=addr if a physical address was specified
572 ioremap I/O mapping (ioremap() and friends)
573 vmalloc vmalloc() area
574 vmap vmap()ed pages
575 user VM_USERMAP area
576 vpages buffer for pages pointers was vmalloced (huge area)
577 N<node>=nr (Only on NUMA kernels)
578 Number of pages allocated on memory node <node>
579
580> cat /proc/vmallocinfo
5810xffffc20000000000-0xffffc20000201000 2101248 alloc_large_system_hash+0x204 ...
582 /0x2c0 pages=512 vmalloc N0=128 N1=128 N2=128 N3=128
5830xffffc20000201000-0xffffc20000302000 1052672 alloc_large_system_hash+0x204 ...
584 /0x2c0 pages=256 vmalloc N0=64 N1=64 N2=64 N3=64
5850xffffc20000302000-0xffffc20000304000 8192 acpi_tb_verify_table+0x21/0x4f...
586 phys=7fee8000 ioremap
5870xffffc20000304000-0xffffc20000307000 12288 acpi_tb_verify_table+0x21/0x4f...
588 phys=7fee7000 ioremap
5890xffffc2000031d000-0xffffc2000031f000 8192 init_vdso_vars+0x112/0x210
5900xffffc2000031f000-0xffffc2000032b000 49152 cramfs_uncompress_init+0x2e ...
591 /0x80 pages=11 vmalloc N0=3 N1=3 N2=2 N3=3
5920xffffc2000033a000-0xffffc2000033d000 12288 sys_swapon+0x640/0xac0 ...
593 pages=2 vmalloc N1=2
5940xffffc20000347000-0xffffc2000034c000 20480 xt_alloc_table_info+0xfe ...
595 /0x130 [x_tables] pages=4 vmalloc N0=4
5960xffffffffa0000000-0xffffffffa000f000 61440 sys_init_module+0xc27/0x1d00 ...
597 pages=14 vmalloc N2=14
5980xffffffffa000f000-0xffffffffa0014000 20480 sys_init_module+0xc27/0x1d00 ...
599 pages=4 vmalloc N1=4
6000xffffffffa0014000-0xffffffffa0017000 12288 sys_init_module+0xc27/0x1d00 ...
601 pages=2 vmalloc N1=2
6020xffffffffa0017000-0xffffffffa0022000 45056 sys_init_module+0xc27/0x1d00 ...
603 pages=10 vmalloc N0=10
560 604
5611.3 IDE devices in /proc/ide 6051.3 IDE devices in /proc/ide
562---------------------------- 606----------------------------
@@ -879,45 +923,44 @@ CPUs.
879The "procs_blocked" line gives the number of processes currently blocked, 923The "procs_blocked" line gives the number of processes currently blocked,
880waiting for I/O to complete. 924waiting for I/O to complete.
881 925
926
8821.9 Ext4 file system parameters 9271.9 Ext4 file system parameters
883------------------------------ 928------------------------------
884Ext4 file system have one directory per partition under /proc/fs/ext4/
885# ls /proc/fs/ext4/hdc/
886group_prealloc max_to_scan mb_groups mb_history min_to_scan order2_req
887stats stream_req
888
889mb_groups:
890This file gives the details of mutiblock allocator buddy cache of free blocks
891
892mb_history:
893Multiblock allocation history.
894 929
895stats: 930Information about mounted ext4 file systems can be found in
896This file indicate whether the multiblock allocator should start collecting 931/proc/fs/ext4. Each mounted filesystem will have a directory in
897statistics. The statistics are shown during unmount 932/proc/fs/ext4 based on its device name (i.e., /proc/fs/ext4/hdc or
933/proc/fs/ext4/dm-0). The files in each per-device directory are shown
934in Table 1-10, below.
898 935
899group_prealloc: 936Table 1-10: Files in /proc/fs/ext4/<devname>
900The multiblock allocator normalize the block allocation request to 937..............................................................................
901group_prealloc filesystem blocks if we don't have strip value set. 938 File Content
902The stripe value can be specified at mount time or during mke2fs. 939 mb_groups details of multiblock allocator buddy cache of free blocks
903 940 mb_history multiblock allocation history
904max_to_scan: 941 stats controls whether the multiblock allocator should start
905How long multiblock allocator can look for a best extent (in found extents) 942 collecting statistics, which are shown during the unmount
906 943 group_prealloc the multiblock allocator will round up allocation
907min_to_scan: 944 requests to a multiple of this tuning parameter if the
908How long multiblock allocator must look for a best extent 945 stripe size is not set in the ext4 superblock
909 946 max_to_scan The maximum number of extents the multiblock allocator
910order2_req: 947 will search to find the best extent
911Multiblock allocator use 2^N search using buddies only for requests greater 948 min_to_scan The minimum number of extents the multiblock allocator
912than or equal to order2_req. The request size is specfied in file system 949 will search to find the best extent
913blocks. A value of 2 indicate only if the requests are greater than or equal 950 order2_req Tuning parameter which controls the minimum size for
914to 4 blocks. 951 requests (as a power of 2) where the buddy cache is
952 used
953 stream_req Files which have fewer blocks than this tunable
954 parameter will have their blocks allocated out of a
955 block group specific preallocation pool, so that small
956 files are packed closely together. Each large file
957 will have its blocks allocated out of its own unique
958 preallocation pool.
959inode_readahead Tuning parameter which controls the maximum number of
960 inode table blocks that ext4's inode table readahead
961 algorithm will pre-read into the buffer cache
962..............................................................................
915 963
916stream_req:
917Files smaller than stream_req are served by the stream allocator, whose
918purpose is to pack requests as close each to other as possible to
919produce smooth I/O traffic. Avalue of 16 indicate that file smaller than 16
920filesystem block size will use group based preallocation.
921 964
922------------------------------------------------------------------------------ 965------------------------------------------------------------------------------
923Summary 966Summary
@@ -1278,6 +1321,18 @@ debugging information is displayed on console.
1278NMI switch that most IA32 servers have fires unknown NMI up, for example. 1321NMI switch that most IA32 servers have fires unknown NMI up, for example.
1279If a system hangs up, try pressing the NMI switch. 1322If a system hangs up, try pressing the NMI switch.
1280 1323
1324panic_on_unrecovered_nmi
1325------------------------
1326
1327The default Linux behaviour on an NMI of either memory or unknown is to continue
1328operation. For many environments such as scientific computing it is preferable
1329that the box is taken out and the error dealt with than an uncorrected
1330parity/ECC error get propogated.
1331
1332A small number of systems do generate NMI's for bizarre random reasons such as
1333power management so the default is off. That sysctl works like the existing
1334panic controls already in that directory.
1335
1281nmi_watchdog 1336nmi_watchdog
1282------------ 1337------------
1283 1338
@@ -1288,12 +1343,24 @@ determine whether or not they are still functioning properly.
1288Because the NMI watchdog shares registers with oprofile, by disabling the NMI 1343Because the NMI watchdog shares registers with oprofile, by disabling the NMI
1289watchdog, oprofile may have more registers to utilize. 1344watchdog, oprofile may have more registers to utilize.
1290 1345
1291maps_protect 1346msgmni
1292------------ 1347------
1348
1349Maximum number of message queue ids on the system.
1350This value scales to the amount of lowmem. It is automatically recomputed
1351upon memory add/remove or ipc namespace creation/removal.
1352When a value is written into this file, msgmni's value becomes fixed, i.e. it
1353is not recomputed anymore when one of the above events occurs.
1354Use auto_msgmni to change this behavior.
1293 1355
1294Enables/Disables the protection of the per-process proc entries "maps" and 1356auto_msgmni
1295"smaps". When enabled, the contents of these files are visible only to 1357-----------
1296readers that are allowed to ptrace() the given process. 1358
1359Enables/Disables automatic recomputing of msgmni upon memory add/remove or
1360upon ipc namespace creation/removal (see the msgmni description above).
1361Echoing "1" into this file enables msgmni automatic recomputing.
1362Echoing "0" turns it off.
1363auto_msgmni default value is 1.
1297 1364
1298 1365
12992.4 /proc/sys/vm - The virtual memory subsystem 13662.4 /proc/sys/vm - The virtual memory subsystem
@@ -1317,15 +1384,18 @@ causes the kernel to prefer to reclaim dentries and inodes.
1317dirty_background_ratio 1384dirty_background_ratio
1318---------------------- 1385----------------------
1319 1386
1320Contains, as a percentage of total system memory, the number of pages at which 1387Contains, as a percentage of the dirtyable system memory (free pages + mapped
1321the pdflush background writeback daemon will start writing out dirty data. 1388pages + file cache, not including locked pages and HugePages), the number of
1389pages at which the pdflush background writeback daemon will start writing out
1390dirty data.
1322 1391
1323dirty_ratio 1392dirty_ratio
1324----------------- 1393-----------------
1325 1394
1326Contains, as a percentage of total system memory, the number of pages at which 1395Contains, as a percentage of the dirtyable system memory (free pages + mapped
1327a process which is generating disk writes will itself start writing out dirty 1396pages + file cache, not including locked pages and HugePages), the number of
1328data. 1397pages at which a process which is generating disk writes will itself start
1398writing out dirty data.
1329 1399
1330dirty_writeback_centisecs 1400dirty_writeback_centisecs
1331------------------------- 1401-------------------------
@@ -1430,7 +1500,7 @@ used because pages_free(1355) is smaller than watermark + protection[2]
1430normal page requirement. If requirement is DMA zone(index=0), protection[0] 1500normal page requirement. If requirement is DMA zone(index=0), protection[0]
1431(=0) is used. 1501(=0) is used.
1432 1502
1433zone[i]'s protection[j] is calculated by following exprssion. 1503zone[i]'s protection[j] is calculated by following expression.
1434 1504
1435(i < j): 1505(i < j):
1436 zone[i]->protection[j] 1506 zone[i]->protection[j]
@@ -2345,22 +2415,29 @@ will be dumped when the <pid> process is dumped. coredump_filter is a bitmask
2345of memory types. If a bit of the bitmask is set, memory segments of the 2415of memory types. If a bit of the bitmask is set, memory segments of the
2346corresponding memory type are dumped, otherwise they are not dumped. 2416corresponding memory type are dumped, otherwise they are not dumped.
2347 2417
2348The following 4 memory types are supported: 2418The following 7 memory types are supported:
2349 - (bit 0) anonymous private memory 2419 - (bit 0) anonymous private memory
2350 - (bit 1) anonymous shared memory 2420 - (bit 1) anonymous shared memory
2351 - (bit 2) file-backed private memory 2421 - (bit 2) file-backed private memory
2352 - (bit 3) file-backed shared memory 2422 - (bit 3) file-backed shared memory
2423 - (bit 4) ELF header pages in file-backed private memory areas (it is
2424 effective only if the bit 2 is cleared)
2425 - (bit 5) hugetlb private memory
2426 - (bit 6) hugetlb shared memory
2353 2427
2354 Note that MMIO pages such as frame buffer are never dumped and vDSO pages 2428 Note that MMIO pages such as frame buffer are never dumped and vDSO pages
2355 are always dumped regardless of the bitmask status. 2429 are always dumped regardless of the bitmask status.
2356 2430
2357Default value of coredump_filter is 0x3; this means all anonymous memory 2431 Note bit 0-4 doesn't effect any hugetlb memory. hugetlb memory are only
2358segments are dumped. 2432 effected by bit 5-6.
2433
2434Default value of coredump_filter is 0x23; this means all anonymous memory
2435segments and hugetlb private memory are dumped.
2359 2436
2360If you don't want to dump all shared memory segments attached to pid 1234, 2437If you don't want to dump all shared memory segments attached to pid 1234,
2361write 1 to the process's proc file. 2438write 0x21 to the process's proc file.
2362 2439
2363 $ echo 0x1 > /proc/1234/coredump_filter 2440 $ echo 0x21 > /proc/1234/coredump_filter
2364 2441
2365When a new process is created, the process inherits the bitmask status from its 2442When a new process is created, the process inherits the bitmask status from its
2366parent. It is useful to set up coredump_filter before the program runs. 2443parent. It is useful to set up coredump_filter before the program runs.
diff --git a/Documentation/filesystems/quota.txt b/Documentation/filesystems/quota.txt
index a590c4093eff..5e8de25bf0f1 100644
--- a/Documentation/filesystems/quota.txt
+++ b/Documentation/filesystems/quota.txt
@@ -3,14 +3,14 @@ Quota subsystem
3=============== 3===============
4 4
5Quota subsystem allows system administrator to set limits on used space and 5Quota subsystem allows system administrator to set limits on used space and
6number of used inodes (inode is a filesystem structure which is associated 6number of used inodes (inode is a filesystem structure which is associated with
7with each file or directory) for users and/or groups. For both used space and 7each file or directory) for users and/or groups. For both used space and number
8number of used inodes there are actually two limits. The first one is called 8of used inodes there are actually two limits. The first one is called softlimit
9softlimit and the second one hardlimit. An user can never exceed a hardlimit 9and the second one hardlimit. An user can never exceed a hardlimit for any
10for any resource. User is allowed to exceed softlimit but only for limited 10resource (unless he has CAP_SYS_RESOURCE capability). User is allowed to exceed
11period of time. This period is called "grace period" or "grace time". When 11softlimit but only for limited period of time. This period is called "grace
12grace time is over, user is not able to allocate more space/inodes until he 12period" or "grace time". When grace time is over, user is not able to allocate
13frees enough of them to get below softlimit. 13more space/inodes until he frees enough of them to get below softlimit.
14 14
15Quota limits (and amount of grace time) are set independently for each 15Quota limits (and amount of grace time) are set independently for each
16filesystem. 16filesystem.
@@ -53,6 +53,12 @@ in parentheses):
53 QUOTA_NL_BSOFTLONGWARN - space (block) softlimit is exceeded 53 QUOTA_NL_BSOFTLONGWARN - space (block) softlimit is exceeded
54 longer than given grace period. 54 longer than given grace period.
55 QUOTA_NL_BSOFTWARN - space (block) softlimit 55 QUOTA_NL_BSOFTWARN - space (block) softlimit
56 - four warnings are also defined for the event when user stops
57 exceeding some limit:
58 QUOTA_NL_IHARDBELOW - inode hardlimit
59 QUOTA_NL_ISOFTBELOW - inode softlimit
60 QUOTA_NL_BHARDBELOW - space (block) hardlimit
61 QUOTA_NL_BSOFTBELOW - space (block) softlimit
56 QUOTA_NL_A_DEV_MAJOR (u32) 62 QUOTA_NL_A_DEV_MAJOR (u32)
57 - major number of a device with the affected filesystem 63 - major number of a device with the affected filesystem
58 QUOTA_NL_A_DEV_MINOR (u32) 64 QUOTA_NL_A_DEV_MINOR (u32)
diff --git a/Documentation/filesystems/ramfs-rootfs-initramfs.txt b/Documentation/filesystems/ramfs-rootfs-initramfs.txt
index 7be232b44ee4..62fe9b1e0890 100644
--- a/Documentation/filesystems/ramfs-rootfs-initramfs.txt
+++ b/Documentation/filesystems/ramfs-rootfs-initramfs.txt
@@ -263,7 +263,7 @@ User Mode Linux, like so:
263 sleep(999999999); 263 sleep(999999999);
264 } 264 }
265 EOF 265 EOF
266 gcc -static hello2.c -o init 266 gcc -static hello.c -o init
267 echo init | cpio -o -H newc | gzip > test.cpio.gz 267 echo init | cpio -o -H newc | gzip > test.cpio.gz
268 # Testing external initramfs using the initrd loading mechanism. 268 # Testing external initramfs using the initrd loading mechanism.
269 qemu -kernel /boot/vmlinuz -initrd test.cpio.gz /dev/zero 269 qemu -kernel /boot/vmlinuz -initrd test.cpio.gz /dev/zero
diff --git a/Documentation/filesystems/relay.txt b/Documentation/filesystems/relay.txt
index 094f2d2f38b1..510b722667ac 100644
--- a/Documentation/filesystems/relay.txt
+++ b/Documentation/filesystems/relay.txt
@@ -294,6 +294,16 @@ user-defined data with a channel, and is immediately available
294(including in create_buf_file()) via chan->private_data or 294(including in create_buf_file()) via chan->private_data or
295buf->chan->private_data. 295buf->chan->private_data.
296 296
297Buffer-only channels
298--------------------
299
300These channels have no files associated and can be created with
301relay_open(NULL, NULL, ...). Such channels are useful in scenarios such
302as when doing early tracing in the kernel, before the VFS is up. In these
303cases, one may open a buffer-only channel and then call
304relay_late_setup_files() when the kernel is ready to handle files,
305to expose the buffered data to the userspace.
306
297Channel 'modes' 307Channel 'modes'
298--------------- 308---------------
299 309
diff --git a/Documentation/filesystems/sysfs.txt b/Documentation/filesystems/sysfs.txt
index 7f27b8f840d0..9e9c348275a9 100644
--- a/Documentation/filesystems/sysfs.txt
+++ b/Documentation/filesystems/sysfs.txt
@@ -248,6 +248,7 @@ The top level sysfs directory looks like:
248block/ 248block/
249bus/ 249bus/
250class/ 250class/
251dev/
251devices/ 252devices/
252firmware/ 253firmware/
253net/ 254net/
@@ -274,6 +275,11 @@ fs/ contains a directory for some filesystems. Currently each
274filesystem wanting to export attributes must create its own hierarchy 275filesystem wanting to export attributes must create its own hierarchy
275below fs/ (see ./fuse.txt for an example). 276below fs/ (see ./fuse.txt for an example).
276 277
278dev/ contains two directories char/ and block/. Inside these two
279directories there are symlinks named <major>:<minor>. These symlinks
280point to the sysfs directory for the given device. /sys/dev provides a
281quick way to lookup the sysfs interface for a device from the result of
282a stat(2) operation.
277 283
278More information can driver-model specific features can be found in 284More information can driver-model specific features can be found in
279Documentation/driver-model/. 285Documentation/driver-model/.
diff --git a/Documentation/filesystems/ubifs.txt b/Documentation/filesystems/ubifs.txt
index 540e9e7f59c5..dd84ea3c10da 100644
--- a/Documentation/filesystems/ubifs.txt
+++ b/Documentation/filesystems/ubifs.txt
@@ -57,7 +57,7 @@ Similarly to JFFS2, UBIFS supports on-the-flight compression which makes
57it possible to fit quite a lot of data to the flash. 57it possible to fit quite a lot of data to the flash.
58 58
59Similarly to JFFS2, UBIFS is tolerant of unclean reboots and power-cuts. 59Similarly to JFFS2, UBIFS is tolerant of unclean reboots and power-cuts.
60It does not need stuff like ckfs.ext2. UBIFS automatically replays its 60It does not need stuff like fsck.ext2. UBIFS automatically replays its
61journal and recovers from crashes, ensuring that the on-flash data 61journal and recovers from crashes, ensuring that the on-flash data
62structures are consistent. 62structures are consistent.
63 63
@@ -86,6 +86,15 @@ norm_unmount (*) commit on unmount; the journal is committed
86fast_unmount do not commit on unmount; this option makes 86fast_unmount do not commit on unmount; this option makes
87 unmount faster, but the next mount slower 87 unmount faster, but the next mount slower
88 because of the need to replay the journal. 88 because of the need to replay the journal.
89bulk_read read more in one go to take advantage of flash
90 media that read faster sequentially
91no_bulk_read (*) do not bulk-read
92no_chk_data_crc skip checking of CRCs on data nodes in order to
93 improve read performance. Use this option only
94 if the flash media is highly reliable. The effect
95 of this option is that corruption of the contents
96 of a file can go unnoticed.
97chk_data_crc (*) do not skip checking CRCs on data nodes
89 98
90 99
91Quick usage instructions 100Quick usage instructions
diff --git a/Documentation/filesystems/vfat.txt b/Documentation/filesystems/vfat.txt
index 2d5e1e582e13..bbac4f1d9056 100644
--- a/Documentation/filesystems/vfat.txt
+++ b/Documentation/filesystems/vfat.txt
@@ -96,6 +96,14 @@ shortname=lower|win95|winnt|mixed
96 emulate the Windows 95 rule for create. 96 emulate the Windows 95 rule for create.
97 Default setting is `lower'. 97 Default setting is `lower'.
98 98
99tz=UTC -- Interpret timestamps as UTC rather than local time.
100 This option disables the conversion of timestamps
101 between local time (as used by Windows on FAT) and UTC
102 (which Linux uses internally). This is particuluarly
103 useful when mounting devices (like digital cameras)
104 that are set to UTC in order to avoid the pitfalls of
105 local time.
106
99<bool>: 0,1,yes,no,true,false 107<bool>: 0,1,yes,no,true,false
100 108
101TODO 109TODO
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index b7522c6cbae3..c4d348dabe94 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -143,7 +143,7 @@ struct file_system_type {
143 143
144The get_sb() method has the following arguments: 144The get_sb() method has the following arguments:
145 145
146 struct file_system_type *fs_type: decribes the filesystem, partly initialized 146 struct file_system_type *fs_type: describes the filesystem, partly initialized
147 by the specific filesystem code 147 by the specific filesystem code
148 148
149 int flags: mount flags 149 int flags: mount flags
@@ -895,9 +895,9 @@ struct dentry_operations {
895 iput() yourself 895 iput() yourself
896 896
897 d_dname: called when the pathname of a dentry should be generated. 897 d_dname: called when the pathname of a dentry should be generated.
898 Usefull for some pseudo filesystems (sockfs, pipefs, ...) to delay 898 Useful for some pseudo filesystems (sockfs, pipefs, ...) to delay
899 pathname generation. (Instead of doing it when dentry is created, 899 pathname generation. (Instead of doing it when dentry is created,
900 its done only when the path is needed.). Real filesystems probably 900 it's done only when the path is needed.). Real filesystems probably
901 dont want to use it, because their dentries are present in global 901 dont want to use it, because their dentries are present in global
902 dcache hash, so their hash should be an invariant. As no lock is 902 dcache hash, so their hash should be an invariant. As no lock is
903 held, d_dname() should not try to modify the dentry itself, unless 903 held, d_dname() should not try to modify the dentry itself, unless