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David Howells
800a964787 CacheFiles: Export things for CacheFiles
Export a number of functions for CacheFiles's use.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Daire Byrne <Daire.Byrne@framestore.com>
2009-04-03 16:42:40 +01:00
David Howells
b510882281 FS-Cache: Implement data I/O part of netfs API
Implement the data I/O part of the FS-Cache netfs API.  The documentation and
API header file were added in a previous patch.

This patch implements the following functions for the netfs to call:

 (*) fscache_attr_changed().

     Indicate that the object has changed its attributes.  The only attribute
     currently recorded is the file size.  Only pages within the set file size
     will be stored in the cache.

     This operation is submitted for asynchronous processing, and will return
     immediately.  It will return -ENOMEM if an out of memory error is
     encountered, -ENOBUFS if the object is not actually cached, or 0 if the
     operation is successfully queued.

 (*) fscache_read_or_alloc_page().
 (*) fscache_read_or_alloc_pages().

     Request data be fetched from the disk, and allocate internal metadata to
     track the netfs pages and reserve disk space for unknown pages.

     These operations perform semi-asynchronous data reads.  Upon returning
     they will indicate which pages they think can be retrieved from disk, and
     will have set in progress attempts to retrieve those pages.

     These will return, in order of preference, -ENOMEM on memory allocation
     error, -ERESTARTSYS if a signal interrupted proceedings, -ENODATA if one
     or more requested pages are not yet cached, -ENOBUFS if the object is not
     actually cached or if there isn't space for future pages to be cached on
     this object, or 0 if successful.

     In the case of the multipage function, the pages for which reads are set
     in progress will be removed from the list and the page count decreased
     appropriately.

     If any read operations should fail, the completion function will be given
     an error, and will also be passed contextual information to allow the
     netfs to fall back to querying the server for the absent pages.

     For each successful read, the page completion function will also be
     called.

     Any pages subsequently tracked by the cache will have PG_fscache set upon
     them on return.  fscache_uncache_page() must be called for such pages.

     If supplied by the netfs, the mark_pages_cached() cookie op will be
     invoked for any pages now tracked.

 (*) fscache_alloc_page().

     Allocate internal metadata to track a netfs page and reserve disk space.

     This will return -ENOMEM on memory allocation error, -ERESTARTSYS on
     signal, -ENOBUFS if the object isn't cached, or there isn't enough space
     in the cache, or 0 if successful.

     Any pages subsequently tracked by the cache will have PG_fscache set upon
     them on return.  fscache_uncache_page() must be called for such pages.

     If supplied by the netfs, the mark_pages_cached() cookie op will be
     invoked for any pages now tracked.

 (*) fscache_write_page().

     Request data be stored to disk.  This may only be called on pages that
     have been read or alloc'd by the above three functions and have not yet
     been uncached.

     This will return -ENOMEM on memory allocation error, -ERESTARTSYS on
     signal, -ENOBUFS if the object isn't cached, or there isn't immediately
     enough space in the cache, or 0 if successful.

     On a successful return, this operation will have queued the page for
     asynchronous writing to the cache.  The page will be returned with
     PG_fscache_write set until the write completes one way or another.  The
     caller will not be notified if the write fails due to an I/O error.  If
     that happens, the object will become available and all pending writes will
     be aborted.

     Note that the cache may batch up page writes, and so it may take a while
     to get around to writing them out.

     The caller must assume that until PG_fscache_write is cleared the page is
     use by the cache.  Any changes made to the page may be reflected on disk.
     The page may even be under DMA.

 (*) fscache_uncache_page().

     Indicate that the cache should stop tracking a page previously read or
     alloc'd from the cache.  If the page was alloc'd only, but unwritten, it
     will not appear on disk.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Daire Byrne <Daire.Byrne@framestore.com>
2009-04-03 16:42:39 +01:00
David Howells
952efe7b78 FS-Cache: Add and document asynchronous operation handling
Add and document asynchronous operation handling for use by FS-Cache's data
storage and retrieval routines.

The following documentation is added to:

	Documentation/filesystems/caching/operations.txt

		       ================================
		       ASYNCHRONOUS OPERATIONS HANDLING
		       ================================

========
OVERVIEW
========

FS-Cache has an asynchronous operations handling facility that it uses for its
data storage and retrieval routines.  Its operations are represented by
fscache_operation structs, though these are usually embedded into some other
structure.

This facility is available to and expected to be be used by the cache backends,
and FS-Cache will create operations and pass them off to the appropriate cache
backend for completion.

To make use of this facility, <linux/fscache-cache.h> should be #included.

===============================
OPERATION RECORD INITIALISATION
===============================

An operation is recorded in an fscache_operation struct:

	struct fscache_operation {
		union {
			struct work_struct fast_work;
			struct slow_work slow_work;
		};
		unsigned long		flags;
		fscache_operation_processor_t processor;
		...
	};

Someone wanting to issue an operation should allocate something with this
struct embedded in it.  They should initialise it by calling:

	void fscache_operation_init(struct fscache_operation *op,
				    fscache_operation_release_t release);

with the operation to be initialised and the release function to use.

The op->flags parameter should be set to indicate the CPU time provision and
the exclusivity (see the Parameters section).

The op->fast_work, op->slow_work and op->processor flags should be set as
appropriate for the CPU time provision (see the Parameters section).

FSCACHE_OP_WAITING may be set in op->flags prior to each submission of the
operation and waited for afterwards.

==========
PARAMETERS
==========

There are a number of parameters that can be set in the operation record's flag
parameter.  There are three options for the provision of CPU time in these
operations:

 (1) The operation may be done synchronously (FSCACHE_OP_MYTHREAD).  A thread
     may decide it wants to handle an operation itself without deferring it to
     another thread.

     This is, for example, used in read operations for calling readpages() on
     the backing filesystem in CacheFiles.  Although readpages() does an
     asynchronous data fetch, the determination of whether pages exist is done
     synchronously - and the netfs does not proceed until this has been
     determined.

     If this option is to be used, FSCACHE_OP_WAITING must be set in op->flags
     before submitting the operation, and the operating thread must wait for it
     to be cleared before proceeding:

		wait_on_bit(&op->flags, FSCACHE_OP_WAITING,
			    fscache_wait_bit, TASK_UNINTERRUPTIBLE);

 (2) The operation may be fast asynchronous (FSCACHE_OP_FAST), in which case it
     will be given to keventd to process.  Such an operation is not permitted
     to sleep on I/O.

     This is, for example, used by CacheFiles to copy data from a backing fs
     page to a netfs page after the backing fs has read the page in.

     If this option is used, op->fast_work and op->processor must be
     initialised before submitting the operation:

		INIT_WORK(&op->fast_work, do_some_work);

 (3) The operation may be slow asynchronous (FSCACHE_OP_SLOW), in which case it
     will be given to the slow work facility to process.  Such an operation is
     permitted to sleep on I/O.

     This is, for example, used by FS-Cache to handle background writes of
     pages that have just been fetched from a remote server.

     If this option is used, op->slow_work and op->processor must be
     initialised before submitting the operation:

		fscache_operation_init_slow(op, processor)

Furthermore, operations may be one of two types:

 (1) Exclusive (FSCACHE_OP_EXCLUSIVE).  Operations of this type may not run in
     conjunction with any other operation on the object being operated upon.

     An example of this is the attribute change operation, in which the file
     being written to may need truncation.

 (2) Shareable.  Operations of this type may be running simultaneously.  It's
     up to the operation implementation to prevent interference between other
     operations running at the same time.

=========
PROCEDURE
=========

Operations are used through the following procedure:

 (1) The submitting thread must allocate the operation and initialise it
     itself.  Normally this would be part of a more specific structure with the
     generic op embedded within.

 (2) The submitting thread must then submit the operation for processing using
     one of the following two functions:

	int fscache_submit_op(struct fscache_object *object,
			      struct fscache_operation *op);

	int fscache_submit_exclusive_op(struct fscache_object *object,
					struct fscache_operation *op);

     The first function should be used to submit non-exclusive ops and the
     second to submit exclusive ones.  The caller must still set the
     FSCACHE_OP_EXCLUSIVE flag.

     If successful, both functions will assign the operation to the specified
     object and return 0.  -ENOBUFS will be returned if the object specified is
     permanently unavailable.

     The operation manager will defer operations on an object that is still
     undergoing lookup or creation.  The operation will also be deferred if an
     operation of conflicting exclusivity is in progress on the object.

     If the operation is asynchronous, the manager will retain a reference to
     it, so the caller should put their reference to it by passing it to:

	void fscache_put_operation(struct fscache_operation *op);

 (3) If the submitting thread wants to do the work itself, and has marked the
     operation with FSCACHE_OP_MYTHREAD, then it should monitor
     FSCACHE_OP_WAITING as described above and check the state of the object if
     necessary (the object might have died whilst the thread was waiting).

     When it has finished doing its processing, it should call
     fscache_put_operation() on it.

 (4) The operation holds an effective lock upon the object, preventing other
     exclusive ops conflicting until it is released.  The operation can be
     enqueued for further immediate asynchronous processing by adjusting the
     CPU time provisioning option if necessary, eg:

	op->flags &= ~FSCACHE_OP_TYPE;
	op->flags |= ~FSCACHE_OP_FAST;

     and calling:

	void fscache_enqueue_operation(struct fscache_operation *op)

     This can be used to allow other things to have use of the worker thread
     pools.

=====================
ASYNCHRONOUS CALLBACK
=====================

When used in asynchronous mode, the worker thread pool will invoke the
processor method with a pointer to the operation.  This should then get at the
container struct by using container_of():

	static void fscache_write_op(struct fscache_operation *_op)
	{
		struct fscache_storage *op =
			container_of(_op, struct fscache_storage, op);
	...
	}

The caller holds a reference on the operation, and will invoke
fscache_put_operation() when the processor function returns.  The processor
function is at liberty to call fscache_enqueue_operation() or to take extra
references.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Daire Byrne <Daire.Byrne@framestore.com>
2009-04-03 16:42:39 +01:00
David Howells
ccc4fc3d11 FS-Cache: Implement the cookie management part of the netfs API
Implement the cookie management part of the FS-Cache netfs client API.  The
documentation and API header file were added in a previous patch.

This patch implements the following three functions:

 (1) fscache_acquire_cookie().

     Acquire a cookie to represent an object to the netfs.  If the object in
     question is a non-index object, then that object and its parent indices
     will be created on disk at this point if they don't already exist.  Index
     creation is deferred because an index may reside in multiple caches.

 (2) fscache_relinquish_cookie().

     Retire or release a cookie previously acquired.  At this point, the
     object on disk may be destroyed.

 (3) fscache_update_cookie().

     Update the in-cache representation of a cookie.  This is used to update
     the auxiliary data for coherency management purposes.

With this patch it is possible to have a netfs instruct a cache backend to
look up, validate and create metadata on disk and to destroy it again.
The ability to actually store and retrieve data in the objects so created is
added in later patches.

Note that these functions will never return an error.  _All_ errors are
handled internally to FS-Cache.

The worst that can happen is that fscache_acquire_cookie() may return a NULL
pointer - which is considered a negative cookie pointer and can be passed back
to any function that takes a cookie without harm.  A negative cookie pointer
merely suppresses caching at that level.

The stub in linux/fscache.h will detect inline the negative cookie pointer and
abort the operation as fast as possible.  This means that the compiler doesn't
have to set up for a call in that case.

See the documentation in Documentation/filesystems/caching/netfs-api.txt for
more information.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Daire Byrne <Daire.Byrne@framestore.com>
2009-04-03 16:42:38 +01:00
David Howells
36c9559022 FS-Cache: Object management state machine
Implement the cache object management state machine.

The following documentation is added to illuminate the working of this state
machine.  It will also be added as:

	Documentation/filesystems/caching/object.txt

	     ====================================================
	     IN-KERNEL CACHE OBJECT REPRESENTATION AND MANAGEMENT
	     ====================================================

==============
REPRESENTATION
==============

FS-Cache maintains an in-kernel representation of each object that a netfs is
currently interested in.  Such objects are represented by the fscache_cookie
struct and are referred to as cookies.

FS-Cache also maintains a separate in-kernel representation of the objects that
a cache backend is currently actively caching.  Such objects are represented by
the fscache_object struct.  The cache backends allocate these upon request, and
are expected to embed them in their own representations.  These are referred to
as objects.

There is a 1:N relationship between cookies and objects.  A cookie may be
represented by multiple objects - an index may exist in more than one cache -
or even by no objects (it may not be cached).

Furthermore, both cookies and objects are hierarchical.  The two hierarchies
correspond, but the cookies tree is a superset of the union of the object trees
of multiple caches:

	    NETFS INDEX TREE               :      CACHE 1     :      CACHE 2
	                                   :                  :
	                                   :   +-----------+  :
	                          +----------->|  IObject  |  :
	      +-----------+       |        :   +-----------+  :
	      |  ICookie  |-------+        :         |        :
	      +-----------+       |        :         |        :   +-----------+
	            |             +------------------------------>|  IObject  |
	            |                      :         |        :   +-----------+
	            |                      :         V        :         |
	            |                      :   +-----------+  :         |
	            V             +----------->|  IObject  |  :         |
	      +-----------+       |        :   +-----------+  :         |
	      |  ICookie  |-------+        :         |        :         V
	      +-----------+       |        :         |        :   +-----------+
	            |             +------------------------------>|  IObject  |
	      +-----+-----+                :         |        :   +-----------+
	      |           |                :         |        :         |
	      V           |                :         V        :         |
	+-----------+     |                :   +-----------+  :         |
	|  ICookie  |------------------------->|  IObject  |  :         |
	+-----------+     |                :   +-----------+  :         |
	      |           V                :         |        :         V
	      |     +-----------+          :         |        :   +-----------+
	      |     |  ICookie  |-------------------------------->|  IObject  |
	      |     +-----------+          :         |        :   +-----------+
	      V           |                :         V        :         |
	+-----------+     |                :   +-----------+  :         |
	|  DCookie  |------------------------->|  DObject  |  :         |
	+-----------+     |                :   +-----------+  :         |
	                  |                :                  :         |
	          +-------+-------+        :                  :         |
	          |               |        :                  :         |
	          V               V        :                  :         V
	    +-----------+   +-----------+  :                  :   +-----------+
	    |  DCookie  |   |  DCookie  |------------------------>|  DObject  |
	    +-----------+   +-----------+  :                  :   +-----------+
	                                   :                  :

In the above illustration, ICookie and IObject represent indices and DCookie
and DObject represent data storage objects.  Indices may have representation in
multiple caches, but currently, non-index objects may not.  Objects of any type
may also be entirely unrepresented.

As far as the netfs API goes, the netfs is only actually permitted to see
pointers to the cookies.  The cookies themselves and any objects attached to
those cookies are hidden from it.

===============================
OBJECT MANAGEMENT STATE MACHINE
===============================

Within FS-Cache, each active object is managed by its own individual state
machine.  The state for an object is kept in the fscache_object struct, in
object->state.  A cookie may point to a set of objects that are in different
states.

Each state has an action associated with it that is invoked when the machine
wakes up in that state.  There are four logical sets of states:

 (1) Preparation: states that wait for the parent objects to become ready.  The
     representations are hierarchical, and it is expected that an object must
     be created or accessed with respect to its parent object.

 (2) Initialisation: states that perform lookups in the cache and validate
     what's found and that create on disk any missing metadata.

 (3) Normal running: states that allow netfs operations on objects to proceed
     and that update the state of objects.

 (4) Termination: states that detach objects from their netfs cookies, that
     delete objects from disk, that handle disk and system errors and that free
     up in-memory resources.

In most cases, transitioning between states is in response to signalled events.
When a state has finished processing, it will usually set the mask of events in
which it is interested (object->event_mask) and relinquish the worker thread.
Then when an event is raised (by calling fscache_raise_event()), if the event
is not masked, the object will be queued for processing (by calling
fscache_enqueue_object()).

PROVISION OF CPU TIME
---------------------

The work to be done by the various states is given CPU time by the threads of
the slow work facility (see Documentation/slow-work.txt).  This is used in
preference to the workqueue facility because:

 (1) Threads may be completely occupied for very long periods of time by a
     particular work item.  These state actions may be doing sequences of
     synchronous, journalled disk accesses (lookup, mkdir, create, setxattr,
     getxattr, truncate, unlink, rmdir, rename).

 (2) Threads may do little actual work, but may rather spend a lot of time
     sleeping on I/O.  This means that single-threaded and 1-per-CPU-threaded
     workqueues don't necessarily have the right numbers of threads.

LOCKING SIMPLIFICATION
----------------------

Because only one worker thread may be operating on any particular object's
state machine at once, this simplifies the locking, particularly with respect
to disconnecting the netfs's representation of a cache object (fscache_cookie)
from the cache backend's representation (fscache_object) - which may be
requested from either end.

=================
THE SET OF STATES
=================

The object state machine has a set of states that it can be in.  There are
preparation states in which the object sets itself up and waits for its parent
object to transit to a state that allows access to its children:

 (1) State FSCACHE_OBJECT_INIT.

     Initialise the object and wait for the parent object to become active.  In
     the cache, it is expected that it will not be possible to look an object
     up from the parent object, until that parent object itself has been looked
     up.

There are initialisation states in which the object sets itself up and accesses
disk for the object metadata:

 (2) State FSCACHE_OBJECT_LOOKING_UP.

     Look up the object on disk, using the parent as a starting point.
     FS-Cache expects the cache backend to probe the cache to see whether this
     object is represented there, and if it is, to see if it's valid (coherency
     management).

     The cache should call fscache_object_lookup_negative() to indicate lookup
     failure for whatever reason, and should call fscache_obtained_object() to
     indicate success.

     At the completion of lookup, FS-Cache will let the netfs go ahead with
     read operations, no matter whether the file is yet cached.  If not yet
     cached, read operations will be immediately rejected with ENODATA until
     the first known page is uncached - as to that point there can be no data
     to be read out of the cache for that file that isn't currently also held
     in the pagecache.

 (3) State FSCACHE_OBJECT_CREATING.

     Create an object on disk, using the parent as a starting point.  This
     happens if the lookup failed to find the object, or if the object's
     coherency data indicated what's on disk is out of date.  In this state,
     FS-Cache expects the cache to create

     The cache should call fscache_obtained_object() if creation completes
     successfully, fscache_object_lookup_negative() otherwise.

     At the completion of creation, FS-Cache will start processing write
     operations the netfs has queued for an object.  If creation failed, the
     write ops will be transparently discarded, and nothing recorded in the
     cache.

There are some normal running states in which the object spends its time
servicing netfs requests:

 (4) State FSCACHE_OBJECT_AVAILABLE.

     A transient state in which pending operations are started, child objects
     are permitted to advance from FSCACHE_OBJECT_INIT state, and temporary
     lookup data is freed.

 (5) State FSCACHE_OBJECT_ACTIVE.

     The normal running state.  In this state, requests the netfs makes will be
     passed on to the cache.

 (6) State FSCACHE_OBJECT_UPDATING.

     The state machine comes here to update the object in the cache from the
     netfs's records.  This involves updating the auxiliary data that is used
     to maintain coherency.

And there are terminal states in which an object cleans itself up, deallocates
memory and potentially deletes stuff from disk:

 (7) State FSCACHE_OBJECT_LC_DYING.

     The object comes here if it is dying because of a lookup or creation
     error.  This would be due to a disk error or system error of some sort.
     Temporary data is cleaned up, and the parent is released.

 (8) State FSCACHE_OBJECT_DYING.

     The object comes here if it is dying due to an error, because its parent
     cookie has been relinquished by the netfs or because the cache is being
     withdrawn.

     Any child objects waiting on this one are given CPU time so that they too
     can destroy themselves.  This object waits for all its children to go away
     before advancing to the next state.

 (9) State FSCACHE_OBJECT_ABORT_INIT.

     The object comes to this state if it was waiting on its parent in
     FSCACHE_OBJECT_INIT, but its parent died.  The object will destroy itself
     so that the parent may proceed from the FSCACHE_OBJECT_DYING state.

(10) State FSCACHE_OBJECT_RELEASING.
(11) State FSCACHE_OBJECT_RECYCLING.

     The object comes to one of these two states when dying once it is rid of
     all its children, if it is dying because the netfs relinquished its
     cookie.  In the first state, the cached data is expected to persist, and
     in the second it will be deleted.

(12) State FSCACHE_OBJECT_WITHDRAWING.

     The object transits to this state if the cache decides it wants to
     withdraw the object from service, perhaps to make space, but also due to
     error or just because the whole cache is being withdrawn.

(13) State FSCACHE_OBJECT_DEAD.

     The object transits to this state when the in-memory object record is
     ready to be deleted.  The object processor shouldn't ever see an object in
     this state.

THE SET OF EVENTS
-----------------

There are a number of events that can be raised to an object state machine:

 (*) FSCACHE_OBJECT_EV_UPDATE

     The netfs requested that an object be updated.  The state machine will ask
     the cache backend to update the object, and the cache backend will ask the
     netfs for details of the change through its cookie definition ops.

 (*) FSCACHE_OBJECT_EV_CLEARED

     This is signalled in two circumstances:

     (a) when an object's last child object is dropped and

     (b) when the last operation outstanding on an object is completed.

     This is used to proceed from the dying state.

 (*) FSCACHE_OBJECT_EV_ERROR

     This is signalled when an I/O error occurs during the processing of some
     object.

 (*) FSCACHE_OBJECT_EV_RELEASE
 (*) FSCACHE_OBJECT_EV_RETIRE

     These are signalled when the netfs relinquishes a cookie it was using.
     The event selected depends on whether the netfs asks for the backing
     object to be retired (deleted) or retained.

 (*) FSCACHE_OBJECT_EV_WITHDRAW

     This is signalled when the cache backend wants to withdraw an object.
     This means that the object will have to be detached from the netfs's
     cookie.

Because the withdrawing releasing/retiring events are all handled by the object
state machine, it doesn't matter if there's a collision with both ends trying
to sever the connection at the same time.  The state machine can just pick
which one it wants to honour, and that effects the other.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Daire Byrne <Daire.Byrne@framestore.com>
2009-04-03 16:42:38 +01:00
David Howells
2868cbea72 FS-Cache: Bit waiting helpers
Add helpers for use with wait_on_bit().

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Daire Byrne <Daire.Byrne@framestore.com>
2009-04-03 16:42:38 +01:00
David Howells
726dd7ff10 FS-Cache: Add netfs registration
Add functions to register and unregister a network filesystem or other client
of the FS-Cache service.  This allocates and releases the cookie representing
the top-level index for a netfs, and makes it available to the netfs.

If the FS-Cache facility is disabled, then the calls are optimised away at
compile time.

Note that whilst this patch may appear to work with FS-Cache enabled and a
netfs attempting to use it, it will leak the cookie it allocates for the netfs
as fscache_relinquish_cookie() is implemented in a later patch.  This will
cause the slab code to emit a warning when the module is removed.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Daire Byrne <Daire.Byrne@framestore.com>
2009-04-03 16:42:38 +01:00
David Howells
955d00917f FS-Cache: Provide a slab for cookie allocation
Provide a slab from which can be allocated the FS-Cache cookies that will be
presented to the netfs.

Also provide a slab constructor and a function to recursively discard a cookie
and its ancestor chain.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Daire Byrne <Daire.Byrne@framestore.com>
2009-04-03 16:42:38 +01:00
David Howells
4c515dd47a FS-Cache: Add cache management
Implement the entry points by which a cache backend may initialise, add,
declare an error upon and withdraw a cache.

Further, an object is created in sysfs under which each cache added will get
an object created:

	/sys/fs/fscache/<cachetag>/

All of this is described in Documentation/filesystems/caching/backend-api.txt
added by a previous patch.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Daire Byrne <Daire.Byrne@framestore.com>
2009-04-03 16:42:37 +01:00
David Howells
0e04d4cefc FS-Cache: Add cache tag handling
Implement two features of FS-Cache:

 (1) The ability to request and release cache tags - names by which a cache may
     be known to a netfs, and thus selected for use.

 (2) An internal function by which a cache is selected by consulting the netfs,
     if the netfs wishes to be consulted.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Daire Byrne <Daire.Byrne@framestore.com>
2009-04-03 16:42:37 +01:00
David Howells
a6891645cf FS-Cache: Root index definition
Add a description of the root index of the cache for later patches to make use
of.

The root index is owned by FS-Cache itself.  When a netfs requests caching
facilities, FS-Cache will, if one doesn't already exist, create an entry in
the root index with the key being the name of the netfs ("AFS" for example),
and the auxiliary data holding the index structure version supplied by the
netfs:

				     FSDEF
				       |
				 +-----------+
				 |           |
				NFS         AFS
			       [v=1]       [v=1]

If an entry with the appropriate name does already exist, the version is
compared.  If the version is different, the entire subtree from that entry
will be discarded and a new entry created.

The new entry will be an index, and a cookie referring to it will be passed to
the netfs.  This is then the root handle by which the netfs accesses the
cache.  It can create whatever objects it likes in that index, including
further indices.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Daire Byrne <Daire.Byrne@framestore.com>
2009-04-03 16:42:37 +01:00
David Howells
7394daa8c6 FS-Cache: Add use of /proc and presentation of statistics
Make FS-Cache create its /proc interface and present various statistical
information through it.  Also provide the functions for updating this
information.

These features are enabled by:

	CONFIG_FSCACHE_PROC
	CONFIG_FSCACHE_STATS
	CONFIG_FSCACHE_HISTOGRAM

The /proc directory for FS-Cache is also exported so that caching modules can
add their own statistics there too.

The FS-Cache module is loadable at this point, and the statistics files can be
examined by userspace:

	cat /proc/fs/fscache/stats
	cat /proc/fs/fscache/histogram

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Daire Byrne <Daire.Byrne@framestore.com>
2009-04-03 16:42:37 +01:00
David Howells
06b3db1b9b FS-Cache: Add main configuration option, module entry points and debugging
Add the main configuration option, allowing FS-Cache to be selected; the
module entry and exit functions and the debugging stuff used by these patches.

The two configuration options added are:

	CONFIG_FSCACHE
	CONFIG_FSCACHE_DEBUG

The first enables the facility, and the second makes the debugging statements
enableable through the "debug" module parameter.  The value of this parameter
is a bitmask as described in:

	Documentation/filesystems/caching/fscache.txt

The module can be loaded at this point, but all it will do at this point in
the patch series is to start up the slow work facility and shut it down again.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Daire Byrne <Daire.Byrne@framestore.com>
2009-04-03 16:42:36 +01:00
David Howells
266cf658ef FS-Cache: Recruit a page flags for cache management
Recruit a page flag to aid in cache management.  The following extra flag is
defined:

 (1) PG_fscache (PG_private_2)

     The marked page is backed by a local cache and is pinning resources in the
     cache driver.

If PG_fscache is set, then things that checked for PG_private will now also
check for that.  This includes things like truncation and page invalidation.
The function page_has_private() had been added to make the checks for both
PG_private and PG_private_2 at the same time.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Daire Byrne <Daire.Byrne@framestore.com>
2009-04-03 16:42:36 +01:00
Theodore Ts'o
e7c8f5079e ext3: Add replace-on-rename hueristics for data=writeback mode
In data=writeback mode, start an asynchronous flush when renaming a
file on top of an already-existing file.  This lowers the probability
of data loss in the case of applications that attempt to replace a
file via using rename().

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2009-04-03 01:34:49 -04:00
Theodore Ts'o
f7ab34ea72 ext3: Add replace-on-truncate hueristics for data=writeback mode
In data=writeback mode, start an asynchronous flush when closing a
file which had been previously truncated down to zero.  This lowers
the probability of data loss in the case of applications that attempt
to replace a file using truncate.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2009-04-03 01:34:35 -04:00
Linus Torvalds
8fe74cf053 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
  Remove two unneeded exports and make two symbols static in fs/mpage.c
  Cleanup after commit 585d3bc06f
  Trim includes of fdtable.h
  Don't crap into descriptor table in binfmt_som
  Trim includes in binfmt_elf
  Don't mess with descriptor table in load_elf_binary()
  Get rid of indirect include of fs_struct.h
  New helper - current_umask()
  check_unsafe_exec() doesn't care about signal handlers sharing
  New locking/refcounting for fs_struct
  Take fs_struct handling to new file (fs/fs_struct.c)
  Get rid of bumping fs_struct refcount in pivot_root(2)
  Kill unsharing fs_struct in __set_personality()
2009-04-02 21:09:10 -07:00
Coly Li
41d577aa35 fs/ufs: return f_fsid for statfs(2)
Make ufs return f_fsid info for statfs(2).

Signed-off-by: Coly Li <coly.li@suse.de>
Cc: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:05:10 -07:00
Coly Li
1c5b45411f fs/sysv: return f_fsid for statfs(2)
Make sysv file system return f_fsid info for statfs(2).

Signed-off-by: Coly Li <coly.li@suse.de>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:05:10 -07:00
Coly Li
2fc7f562b4 fs/squashfs: return f_fsid for statfs(2)
Make squashfs return f_fsid info for statfs(2).

Signed-off-by: Coly Li <coly.li@suse.de>
Cc: Phillip Lougher <phillip@lougher.demon.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:05:10 -07:00
Coly Li
651d062304 fs/reiserfs: return f_fsid for statfs(2)
Make reiserfs3 return f_fsid info for statfs(2).  By Andreas' suggestion,
this patch populates a persistent f_fsid between boots/mounts with help of
on-disk uuid record.

Randy Dunlap reported a compiling error from v2 patch like:
    fs/built-in.o: In function `reiserfs_statfs':
    super.c:(.text+0x7332b): undefined reference to `crc32_le'
    super.c:(.text+0x7333f): undefined reference to `crc32_le'
Also he provided helpful solution to fix this error. The modification of v3
patch is based on Randy's suggestion, add 'select CRC32' in fs/reiserfs/Kconfig.

Signed-off-by: Coly Li <coly.li@suse.de>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:05:10 -07:00
Coly Li
5b76dc066a fs/qnx4: return f_fsid for statfs(2)
Make qnx4 file system return f_fsid info for statfs(2).

Signed-off-by: Coly Li <coly.li@suse.de>
Acked-by: Anders Larsen <al@alarsen.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:05:10 -07:00
Coly Li
197e671ee1 fs/omfs: return f_fsid for statfs(2)
Make omfs return f_fsid info for statfs(2).

Signed-off-by: Coly Li <coly.li@suse.de>
Acked-by: Bob Copeland <me@bobcopeland.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:05:10 -07:00
Coly Li
054475d2af fs/minix: return f_fsid for statfs(2)
Make minix file system return f_fsid info for statfs(2).

Signed-off-by: Coly Li <coly.li@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:05:09 -07:00
Coly Li
2430c4daf9 fs/isofs: return f_fsid for statfs(2)
Make isofs return f_fsid info for statfs(2).

Signed-off-by: Coly Li <coly.li@suse.de>
Cc: Jan Kara <jack@ucw.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:05:09 -07:00
Coly Li
604d295c26 fs/hpfs: return f_fsid for statfs(2)
Make hpfs return f_fsid info for statfs(2).

Signed-off-by: Coly Li <coly.li@suse.de>
Cc: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:05:09 -07:00
Coly Li
25564dd869 fs/hfsplus: return f_fsid for statfs(2)
Make hfsplus return f_fsid info for statfs(2).

Signed-off-by: Coly Li <coly.li@suse.de>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:05:09 -07:00
Coly Li
7dd2c000ff fs/hfs: return f_fsid for statfs(2)
Make hfs return f_fsid info for statfs(2).

Signed-off-by: Coly Li <coly.li@suse.de>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:05:09 -07:00
Coly Li
aac49b7543 fs/fat: return f_fsid for statfs(2)
Make fat return f_fsid info for statfs(2).

Signed-off-by: Coly Li <coly.li@suse.de>
Acked-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:05:09 -07:00
Coly Li
514c91a9cc fs/efs: return f_fsid for statfs(2)
Make efs return f_fsid info for statfs(2), and do a little variable
renaming in efs_statfs().

Signed-off-by: Coly Li <coly.li@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:05:09 -07:00
Coly Li
94ea77ac69 fs/cramfs: return f_fsid for statfs(2)
Make cramfs return f_fsid info for statfs(2).

Signed-off-by: Coly Li <coly.li@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:05:08 -07:00
Coly Li
8587246a00 fs/befs: return f_fsid for statfs(2)
Make befs return f_fsid info for statfs(2).

Signed-off-by: Coly Li <coly.li@suse.de>
Cc: Sergey S. Kostyliov <rathamahata@php4.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:05:08 -07:00
Coly Li
a6a2a73c4d fs/affs: return f_fsid for statfs(2)
Make affs return f_fsid info for statfs(2).

Signed-off-by: Coly Li <coly.li@suse.de>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:05:08 -07:00
Coly Li
accb401220 fs/adfs: return f_fsid for statfs(2)
Currently many file systems in Linux kernel do not return f_fsid in statfs
info, the value is set as 0 in vfs layer.  Anyway, in some conditions,
f_fsid from statfs(2) is useful, especially being used as (f_fsid, ino)
pair to uniquely identify a file.

Basic idea of the patches is generating a unique fs ID by
huge_encode_dev(sb->s_bdev->bd_dev) during file system mounting life time
(no endian consistent issue).  sb is a point of struct super_block of
current mounted file system being accessed by statfs(2).

This patch:

Make adfs return f_fsid info for statfs(2), and do a little variable
renaming in adfs_statfs().

Signed-off-by: Coly Li <coly.li@suse.de>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: "Sergey S. Kostyliov" <rathamahata@php4.ru>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz>
Cc: Dave Kleikamp <shaggy@austin.ibm.com>
Cc: Bob Copeland <me@bobcopeland.com>
Cc: Anders Larsen <al@alarsen.net>
Cc: Phillip Lougher <phillip@lougher.demon.co.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Evgeniy Dushistov <dushistov@mail.ru>
Cc: Jan Kara <jack@suse.cz>
Cc: Andreas Dilger <adilger@sun.com>
Cc: Jamie Lokier <jamie@shareable.org>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:05:08 -07:00
Gerd Hoffmann
10c7db2792 preadv/pwritev: switch compat readv/preadv/writev/pwritev from fget to fget_light
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <linux-api@vger.kernel.org>
Cc: <linux-arch@vger.kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:05:08 -07:00
Gerd Hoffmann
f3554f4bc6 preadv/pwritev: Add preadv and pwritev system calls.
This patch adds preadv and pwritev system calls.  These syscalls are a
pretty straightforward combination of pread and readv (same for write).
They are quite useful for doing vectored I/O in threaded applications.
Using lseek+readv instead opens race windows you'll have to plug with
locking.

Other systems have such system calls too, for example NetBSD, check
here: http://www.daemon-systems.org/man/preadv.2.html

The application-visible interface provided by glibc should look like
this to be compatible to the existing implementations in the *BSD family:

  ssize_t preadv(int d, const struct iovec *iov, int iovcnt, off_t offset);
  ssize_t pwritev(int d, const struct iovec *iov, int iovcnt, off_t offset);

This prototype has one problem though: On 32bit archs is the (64bit)
offset argument unaligned, which the syscall ABI of several archs doesn't
allow to do.  At least s390 needs a wrapper in glibc to handle this.  As
we'll need a wrappers in glibc anyway I've decided to push problem to
glibc entriely and use a syscall prototype which works without
arch-specific wrappers inside the kernel: The offset argument is
explicitly splitted into two 32bit values.

The patch sports the actual system call implementation and the windup in
the x86 system call tables.  Other archs follow as separate patches.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <linux-api@vger.kernel.org>
Cc: <linux-arch@vger.kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:05:08 -07:00
Gerd Hoffmann
6949a6318e preadv/pwritev: create compat_writev()
Factor out some code from compat_sys_writev() which can be shared with the
upcoming compat_sys_pwritev().

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <linux-api@vger.kernel.org>
Cc: <linux-arch@vger.kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:05:07 -07:00
Gerd Hoffmann
dac1213842 preadv/pwritev: create compat_readv()
This patch series:

Implement the preadv() and pwritev() syscalls.  *BSD has this syscall for
quite some time.

Test code:

#if 0
set -x
gcc -Wall -O2 -o preadv $0
exit 0
#endif
/*
 * preadv demo / test
 *
 * (c) 2008 Gerd Hoffmann <kraxel@redhat.com>
 *
 * build with "sh $thisfile"
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <inttypes.h>
#include <sys/uio.h>

/* ----------------------------------------------------------------- */
/* syscall windup                                                    */

#include <sys/syscall.h>
#if 0
/* WARNING: Be sure you know what you are doing if you enable this.
 * linux syscall code isn't upstream yet, syscall numbers are subject
 * to change */
# ifndef __NR_preadv
#  ifdef __i386__
#   define __NR_preadv  333
#   define __NR_pwritev 334
#  endif
#  ifdef __x86_64__
#   define __NR_preadv  295
#   define __NR_pwritev 296
#  endif
# endif
#endif
#ifndef __NR_preadv
# error preadv/pwritev syscall numbers are unknown
#endif

static ssize_t preadv(int fd, const struct iovec *iov, int iovcnt, off_t offset)
{
    uint32_t pos_high = (offset >> 32) & 0xffffffff;
    uint32_t pos_low  =  offset        & 0xffffffff;

    return syscall(__NR_preadv, fd, iov, iovcnt, pos_high, pos_low);
}

static ssize_t pwritev(int fd, const struct iovec *iov, int iovcnt, off_t offset)
{
    uint32_t pos_high = (offset >> 32) & 0xffffffff;
    uint32_t pos_low  =  offset        & 0xffffffff;

    return syscall(__NR_pwritev, fd, iov, iovcnt, pos_high, pos_low);
}

/* ----------------------------------------------------------------- */
/* demo/test app                                                     */

static char filename[] = "/tmp/preadv-XXXXXX";
static char outbuf[11] = "0123456789";
static char inbuf[11]  = "----------";

static struct iovec ovec[2] = {{
        .iov_base = outbuf + 5,
        .iov_len  = 5,
    },{
        .iov_base = outbuf + 0,
        .iov_len  = 5,
    }};

static struct iovec ivec[3] = {{
        .iov_base = inbuf + 6,
        .iov_len  = 2,
    },{
        .iov_base = inbuf + 4,
        .iov_len  = 2,
    },{
        .iov_base = inbuf + 2,
        .iov_len  = 2,
    }};

void cleanup(void)
{
    unlink(filename);
}

int main(int argc, char **argv)
{
    int fd, rc;

    fd = mkstemp(filename);
    if (-1 == fd) {
        perror("mkstemp");
        exit(1);
    }
    atexit(cleanup);

    /* write to file: "56789-01234" */
    rc = pwritev(fd, ovec, 2, 0);
    if (rc < 0) {
        perror("pwritev");
        exit(1);
    }

    /* read from file: "78-90-12" */
    rc = preadv(fd, ivec, 3, 2);
    if (rc < 0) {
        perror("preadv");
        exit(1);
    }

    printf("result  : %s\n", inbuf);
    printf("expected: %s\n", "--129078--");
    exit(0);
}

This patch:

Factor out some code from compat_sys_readv() which can be shared with the
upcoming compat_sys_preadv().

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <linux-api@vger.kernel.org>
Cc: <linux-arch@vger.kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:05:07 -07:00
David VomLehn
98310e581e cramfs: propagate uncompression errors
Decompression errors can arise due to corruption of compressed blocks on
flash or in memory.  This patch propagates errors detected during
decompression back to the block layer.

Signed-off-by: David VomLehn <dvomlehn@cisco.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:05:07 -07:00
Mike Frysinger
ab4ad55512 bin_elf_fdpic: check the return value of clear_user
Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Greg Ungerer <gerg@snapgear.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:05:01 -07:00
Roel Kluin
880fe76ee6 hppfs: hppfs_read_file() may return -ERROR
hppfs_read_file() may return (ssize_t) -ENOMEM, or -EFAULT.  When stored
in size_t 'count', these errors will not be noticed, a large value will be
added to *ppos.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:04:53 -07:00
Jan Kara
695f6ae0dc ext3: avoid false EIO errors
Sometimes block_write_begin() can map buffers in a page but later we
fail to copy data into those buffers (because the source page has been
paged out in the mean time).  We then end up with !uptodate mapped
buffers.  To add a bit more to the confusion, block_write_end() does
not commit any data (and thus does not any mark buffers as uptodate) if
we didn't succeed with copying all the data.

Commit f4fc66a894 (ext3: convert to new
aops) missed these cases and thus we were inserting non-uptodate
buffers to transaction's list which confuses JBD code and it reports IO
errors, aborts a transaction and generally makes users afraid about
their data ;-P.

This patch fixes the problem by reorganizing ext3_..._write_end() code
to first call block_write_end() to mark buffers with valid data
uptodate and after that we file only uptodate buffers to transaction's
lists.

We also fix a problem where we could leave blocks allocated beyond i_size
(i_disksize in fact) because of failed write. We now add inode to orphan
list when write fails (to be safe in case we crash) and then truncate blocks
beyond i_size in a separate transaction.

Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:04:52 -07:00
Bryan Donlan
de18f3b2d6 ext3: return -EIO not -ESTALE on directory traversal through deleted inode
ext3_iget() returns -ESTALE if invoked on a deleted inode, in order to
report errors to NFS properly.  However, in ext[234]_lookup(), this
-ESTALE can be propagated to userspace if the filesystem is corrupted such
that a directory entry references a deleted inode.  This leads to a
misleading error message - "Stale NFS file handle" - and confusion on the
part of the admin.

The bug can be easily reproduced by creating a new filesystem, making a
link to an unused inode using debugfs, then mounting and attempting to ls
-l said link.

This patch thus changes ext3_lookup to return -EIO if it receives -ESTALE
from ext3_iget(), as ext3 does for other filesystem metadata corruption;
and also invokes the appropriate ext*_error functions when this case is
detected.

Signed-off-by: Bryan Donlan <bdonlan@gmail.com>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:04:52 -07:00
Wei Yongjun
45f9021780 ext3: use unsigned instead of int for type of blocksize in fs/ext3/namei.c
Use unsigned instead of int for the parameter which carries a blocksize.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:04:52 -07:00
Jan Kara
ecca9af0a9 jbd: fix oops in jbd_journal_init_inode() on corrupted fs
On 32-bit system with CONFIG_LBD getblk can fail because provided block
number is too big. Make JBD gracefully handle that.

Signed-off-by: Jan Kara <jack@suse.cz>
Cc: <dmaciejak@fortinet.com>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:04:52 -07:00
Cyrus Massoumi
039fd8ce62 ext3: remove the BKL in ext3/ioctl.c
Reformat ext3/ioctl.c to make it look more like ext4/ioctl.c and remove
the BKL around ext3_ioctl().

Signed-off-by: Cyrus Massoumi <cyrusm@gmx.net>
Cc: <linux-ext4@vger.kernel.org>
Acked-by: Jan Kara <jack@ucw.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:04:52 -07:00
Nikanth Karthikesan
97f76d3d19 vfs: check bh->b_blocknr only if BH_Mapped is set
Check bh->b_blocknr only if BH_Mapped is set.

akpm: I doubt if b_blocknr is ever uninitialised here, but it could
conceivably cause a problem if we're doing a lookup for block zero.

Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:04:49 -07:00
Jeff Layton
d2caa3c549 writeback: guard against jiffies wraparound on inode->dirtied_when checks (try #3)
The dirtied_when value on an inode is supposed to represent the first time
that an inode has one of its pages dirtied.  This value is in units of
jiffies.  It's used in several places in the writeback code to determine
when to write out an inode.

The problem is that these checks assume that dirtied_when is updated
periodically.  If an inode is continuously being used for I/O it can be
persistently marked as dirty and will continue to age.  Once the time
compared to is greater than or equal to half the maximum of the jiffies
type, the logic of the time_*() macros inverts and the opposite of what is
needed is returned.  On 32-bit architectures that's just under 25 days
(assuming HZ == 1000).

As the least-recently dirtied inode, it'll end up being the first one that
pdflush will try to write out.  sync_sb_inodes does this check:

	/* Was this inode dirtied after sync_sb_inodes was called? */
 	if (time_after(inode->dirtied_when, start))
 		break;

...but now dirtied_when appears to be in the future.  sync_sb_inodes bails
out without attempting to write any dirty inodes.  When this occurs,
pdflush will stop writing out inodes for this superblock.  Nothing can
unwedge it until jiffies moves out of the problematic window.

This patch fixes this problem by changing the checks against dirtied_when
to also check whether it appears to be in the future.  If it does, then we
consider the value to be far in the past.

This should shrink the problematic window of time to such a small period
(30s) as not to matter.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Acked-by: Ian Kent <raven@themaw.net>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:04:48 -07:00
Wu Fengguang
b6fac63cc1 vfs: skip I_CLEAR state inodes
clear_inode() will switch inode state from I_FREEING to I_CLEAR, and do so
_outside_ of inode_lock.  So any I_FREEING testing is incomplete without a
coupled testing of I_CLEAR.

So add I_CLEAR tests to drop_pagecache_sb(), generic_sync_sb_inodes() and
add_dquot_ref().

Masayoshi MIZUMA discovered the bug in drop_pagecache_sb() and Jan Kara
reminds fixing the other two cases.

Masayoshi MIZUMA has a nice panic flow:

=====================================================================
            [process A]               |        [process B]
 |                                    |
 |    prune_icache()                  | drop_pagecache()
 |      spin_lock(&inode_lock)        |   drop_pagecache_sb()
 |      inode->i_state |= I_FREEING;  |       |
 |      spin_unlock(&inode_lock)      |       V
 |          |                         |     spin_lock(&inode_lock)
 |          V                         |         |
 |      dispose_list()                |         |
 |        list_del()                  |         |
 |        clear_inode()               |         |
 |          inode->i_state = I_CLEAR  |         |
 |            |                       |         V
 |            |                       |      if (inode->i_state & (I_FREEING|I_WILL_FREE))
 |            |                       |              continue;           <==== NOT MATCH
 |            |                       |
 |            |                       | (DANGER from here on! Accessing disposing inode!)
 |            |                       |
 |            |                       |      __iget()
 |            |                       |        list_move() <===== PANIC on poisoned list !!
 V            V                       |
(time)
=====================================================================

Reported-by: Masayoshi MIZUMA <m.mizuma@jp.fujitsu.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:04:48 -07:00
David Howells
33e5d76979 nommu: fix a number of issues with the per-MM VMA patch
Fix a number of issues with the per-MM VMA patch:

 (1) Make mmap_pages_allocated an atomic_long_t, just in case this is used on
     a NOMMU system with more than 2G pages.  Makes no difference on a 32-bit
     system.

 (2) Report vma->vm_pgoff * PAGE_SIZE as a 64-bit value, not a 32-bit value,
     lest it overflow.

 (3) Move the allocation of the vm_area_struct slab back for fork.c.

 (4) Use KMEM_CACHE() for both vm_area_struct and vm_region slabs.

 (5) Use BUG_ON() rather than if () BUG().

 (6) Make the default validate_nommu_regions() a static inline rather than a
     #define.

 (7) Make free_page_series()'s objection to pages with a refcount != 1 more
     informative.

 (8) Adjust the __put_nommu_region() banner comment to indicate that the
     semaphore must be held for writing.

 (9) Limit the number of warnings about munmaps of non-mmapped regions.

Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Greg Ungerer <gerg@snapgear.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:04:48 -07:00
Jan Kara
146bca72c7 udf: Don't write integrity descriptor too often
We update information in logical volume integrity descriptor after each
allocation (as LVID contains free space, number of directories and files on
disk etc.). If the filesystem is on some phase change media, this leads to its
quick degradation as such media is able to handle only 10000 overwrites or so.
We solve the problem by writing new information into LVID only on umount,
remount-ro and sync. This solves the problem at the price of longer media
inconsistency (previously media became consistent after pdflush flushed dirty
LVID buffer) but that should be acceptable.

Report by and patch written in cooperation with
Rich Coe <Richard.Coe@med.ge.com>.

Signed-off-by: Jan Kara <jack@suse.cz>
2009-04-02 13:36:28 +02:00
Jan Kara
4034600516 udf: Try anchor in block 256 first
Anchor block can be located at several places on the medium. Two of the
locations are relative to media end which is problematic to detect. Also
some drives report some block as last but are not able to read it or any
block nearby before it. So let's first try block 256 and if it is all fine,
don't look at other possible locations of anchor blocks to avoid IO errors.
This change required a larger reorganization of code but the new code is
hopefully more readable and definitely shorter.

Signed-off-by: Jan Kara <jack@suse.cz>
2009-04-02 12:29:56 +02:00
Jan Kara
225feded89 udf: Some type fixes and cleanups
Make udf_check_valid() return 1 if the validity check passed and 0 otherwise.
So far it was the other way around which was a bit confusing. Also make
udf_vrs() return loff_t which is really the type it should return (not int).

Signed-off-by: Jan Kara <jack@suse.cz>
2009-04-02 12:29:55 +02:00
Clemens Ladisch
1197e4dfcf udf: use hardware sector size
This patch makes the UDF FS driver use the hardware sector size as the
default logical block size, which is required by the UDF specifications.
While the previous default of 2048 bytes was correct for optical disks,
it was not for hard disks or USB storage devices, and made it impossible
to use such a device with the default mount options.  (The Linux mkudffs
tool uses a default block size of 2048 bytes even on devices with
smaller hardware sectors, so this bug is unlikely to be noticed unless
UDF-formatted USB storage devices are exchanged with other OSs.)

To avoid regressions for people who use loopback optical disk images or
who used the (sometimes wrong) defaults of mkudffs, we also try with
a block size of 2048 bytes if no anchor was found with the hardware
sector size.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Jan Kara <jack@suse.cz>
2009-04-02 12:29:55 +02:00
Clemens Ladisch
4136801aec udf: fix novrs mount option
The novrs mount option was broken due to a missing break.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Jan Kara <jack@suse.cz>
2009-04-02 12:29:54 +02:00
Jan Kara
59285c28d1 udf: Fix oops when invalid character in filename occurs
Functions udf_CS0toNLS() and udf_NLStoCS0() didn't count with the fact that
NLS can return negative length when invalid character is given to it for
conversion. Thus interesting things could happen (such as overwriting random
memory with the rest of filename). Add appropriate checks.

Signed-off-by: Jan Kara <jack@suse.cz>
2009-04-02 12:29:53 +02:00
Coly Li
557f5a1468 udf: return f_fsid for statfs(2)
This patch makes udf return f_fsid info for statfs(2).

Signed-off-by: Coly Li <coly.li@suse.de>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Jan Kara <jack@suse.cz>
2009-04-02 12:29:53 +02:00
Jan Kara
f90981fed9 udf: Add checks to not underflow sector_t
Signed-off-by: Jan Kara <jack@suse.cz>
2009-04-02 12:29:52 +02:00
Marcin Slusarz
87bc730c07 udf: fix default mode and dmode options handling
On x86 (and several other archs) mode_t is defined as "unsigned short"
and comparing unsigned shorts to negative ints is broken (because short
is promoted to int and then compared). Fix it.

Reported-and-tested-by: Laurent Riffard <laurent.riffard@free.fr>
Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2009-04-02 12:29:52 +02:00
Jan Kara
e650b94add udf: fix sparse warnings:
Fix sparse warnings:

  fs/udf/balloc.c:843:3: warning: returning void-valued expression
  fs/udf/balloc.c:847:3: warning: returning void-valued expression
  fs/udf/balloc.c:851:3: warning: returning void-valued expression
  fs/udf/balloc.c:855:3: warning: returning void-valued expression

Reported-by: Hannes Eder <hannes@hanneseder.net>
Signed-off-by: Jan Kara <jack@suse.cz>
2009-04-02 12:29:51 +02:00
roel kluin
30930554f2 udf: unsigned last[i] cannot be less than 0
unsigned last[i] cannot be less than 0

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2009-04-02 12:29:50 +02:00
Marcin Slusarz
7ac9bcd5da udf: implement mode and dmode mounting options
"dmode" allows overriding permissions of directories and
"mode" allows overriding permissions of files.

Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Jan Kara <jack@suse.cz>
2009-04-02 12:29:50 +02:00
Marcin Slusarz
530f1a5e3e udf: reduce stack usage of udf_get_filename
Allocate strings with kmalloc.

Checkstack output:
Before: udf_get_filename:          600
After:  udf_get_filename:          136

Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Jan Kara <jack@suse.cz>
2009-04-02 12:29:49 +02:00
Marcin Slusarz
ba9aadd80c udf: reduce stack usage of udf_load_pvoldesc
Allocate strings with kmalloc.

Checkstack output:
Before: udf_process_sequence:      712
After:  udf_process_sequence:      200

Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2009-04-02 12:29:48 +02:00
Pekka Enberg
97e961fdbf Fix the udf code not to pass structs on stack where possible.
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Jan Kara <jack@suse.cz>
2009-04-02 12:29:47 +02:00
Pekka Enberg
5ca4e4be84 Remove struct typedefs from fs/udf/ecma_167.h et al.
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Jan Kara <jack@suse.cz>
2009-04-02 12:29:47 +02:00
Felix Blyakher
f36345ff9a Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6 into for-linus 2009-04-01 16:58:39 -05:00
Linus Torvalds
4fe70410d9 Merge branch 'for-linus' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6
* 'for-linus' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6: (58 commits)
  SUNRPC: Ensure IPV6_V6ONLY is set on the socket before binding to a port
  NSM: Fix unaligned accesses in nsm_init_private()
  NFS: Simplify logic to compare socket addresses in client.c
  NFS: Start PF_INET6 callback listener only if IPv6 support is available
  lockd: Start PF_INET6 listener only if IPv6 support is available
  SUNRPC: Remove CONFIG_SUNRPC_REGISTER_V4
  SUNRPC: rpcb_register() should handle errors silently
  SUNRPC: Simplify kernel RPC service registration
  SUNRPC: Simplify svc_unregister()
  SUNRPC: Allow callers to pass rpcb_v4_register a NULL address
  SUNRPC: rpcbind actually interprets r_owner string
  SUNRPC: Clean up address type casts in rpcb_v4_register()
  SUNRPC: Don't return EPROTONOSUPPORT in svc_register()'s helpers
  SUNRPC: Use IPv4 loopback for registering AF_INET6 kernel RPC services
  SUNRPC: Set IPV6ONLY flag on PF_INET6 RPC listener sockets
  NFS: Revert creation of IPv6 listeners for lockd and NFSv4 callbacks
  SUNRPC: Remove @family argument from svc_create() and svc_create_pooled()
  SUNRPC: Change svc_create_xprt() to take a @family argument
  SUNRPC: svc_setup_socket() gets protocol family from socket
  SUNRPC: Pass a family argument to svc_register()
  ...
2009-04-01 10:58:42 -07:00
Linus Torvalds
395d73413c Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (33 commits)
  ext4: Regularize mount options
  ext4: fix locking typo in mballoc which could cause soft lockup hangs
  ext4: fix typo which causes a memory leak on error path
  jbd2: Update locking coments
  ext4: Rename pa_linear to pa_type
  ext4: add checks of block references for non-extent inodes
  ext4: Check for an valid i_mode when reading the inode from disk
  ext4: Use WRITE_SYNC for commits which are caused by fsync()
  ext4: Add auto_da_alloc mount option
  ext4: Use struct flex_groups to calculate get_orlov_stats()
  ext4: Use atomic_t's in struct flex_groups
  ext4: remove /proc tuning knobs
  ext4: Add sysfs support
  ext4: Track lifetime disk writes
  ext4: Fix discard of inode prealloc space with delayed allocation.
  ext4: Automatically allocate delay allocated blocks on rename
  ext4: Automatically allocate delay allocated blocks on close
  ext4: add EXT4_IOC_ALLOC_DA_BLKS ioctl
  ext4: Simplify delalloc code by removing mpage_da_writepages()
  ext4: Save stack space by removing fake buffer heads
  ...
2009-04-01 10:57:49 -07:00
Trond Myklebust
cc85906110 Merge branch 'devel' into for-linus 2009-04-01 13:28:15 -04:00
Mans Rullgard
ad5b365c12 NSM: Fix unaligned accesses in nsm_init_private()
This fixes unaligned accesses in nsm_init_private() when
creating nlm_reboot keys.

Signed-off-by: Mans Rullgard <mans@mansr.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-04-01 13:24:14 -04:00
Linus Torvalds
c226fd659f Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable
* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable:
  Btrfs: try to free metadata pages when we free btree blocks
  Btrfs: add extra flushing for renames and truncates
  Btrfs: make sure btrfs_update_delayed_ref doesn't increase ref_mod
  Btrfs: optimize fsyncs on old files
  Btrfs: tree logging unlink/rename fixes
  Btrfs: Make sure i_nlink doesn't hit zero too soon during log replay
  Btrfs: limit balancing work while flushing delayed refs
  Btrfs: readahead checksums during btrfs_finish_ordered_io
  Btrfs: leave btree locks spinning more often
  Btrfs: Only let very young transactions grow during commit
  Btrfs: Check for a blocking lock before taking the spin
  Btrfs: reduce stack in cow_file_range
  Btrfs: reduce stalls during transaction commit
  Btrfs: process the delayed reference queue in clusters
  Btrfs: try to cleanup delayed refs while freeing extents
  Btrfs: reduce stack usage in some crucial tree balancing functions
  Btrfs: do extent allocation and reference count updates in the background
  Btrfs: don't preallocate metadata blocks during btrfs_search_slot
2009-04-01 10:20:44 -07:00
Ian Kent
8f63aaa8b9 autofs4: fix lookup deadlock
A deadlock can occur when user space uses a signal (autofs version 4 uses
SIGCHLD for this) to effect expire completion.

The order of events is:

Expire process completes, but before being able to send SIGCHLD to it's parent
...

Another process walks onto a different mount point and drops the directory
inode semaphore prior to sending the request to the daemon as it must ...

A third process does an lstat on on the expired mount point causing it to wait
on expire completion (unfortunately) holding the directory semaphore.

The mount request then arrives at the daemon which does an lstat and,
deadlock.

For some time I was concerned about releasing the directory semaphore around
the expire wait in autofs4_lookup as well as for the mount call back.  I
finally realized that the last round of changes in this function made the
expiring dentry and the lookup dentry separate and distinct so the check and
possible wait can be done anywhere prior to the mount call back.  This patch
moves the check to just before the mount call back and inside the directory
inode mutex release.

Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-01 08:59:23 -07:00
Ian Kent
56fcef7511 autofs4: cleanup expire code duplication
A significant portion of the autofs_dev_ioctl_expire() and
autofs4_expire_multi() functions is duplicated code.  This patch cleans that
up.

Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-01 08:59:23 -07:00
Johannes Weiner
00fcf2cb6f ecryptfs: use kzfree()
Use kzfree() instead of memset() + kfree().

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Pekka Enberg <penberg@cs.helsinki.fi>
Acked-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-01 08:59:23 -07:00
Wu Fengguang
c3b1b1cbf0 ramfs: add support for "mode=" mount option
Addresses http://bugzilla.kernel.org/show_bug.cgi?id=12843

"I use ramfs instead of tmpfs for /tmp because I don't use swap on my
laptop.  Some apps need 1777 mode for /tmp directory, but ramfs does not
support 'mode=' mount option."

Reported-by: Avan Anishchuk <matimatik@gmail.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-01 08:59:22 -07:00
Davide Libenzi
395108880e epoll keyed wakeups: make eventfd use keyed wakeups
Introduce keyed event wakeups inside the eventfd code.

Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Miller <davem@davemloft.net>
Cc: William Lee Irwin III <wli@movementarian.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-01 08:59:20 -07:00
Davide Libenzi
2dfa4eeab0 epoll keyed wakeups: teach epoll about hints coming with the wakeup key
Use the events hint now sent by some devices, to avoid unnecessary wakeups
for events that are of no interest for the caller.  This code handles both
devices that are sending keyed events, and the ones that are not (and
event the ones that sometimes send events, and sometimes don't).

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Miller <davem@davemloft.net>
Cc: William Lee Irwin III <wli@movementarian.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-01 08:59:20 -07:00
Davide Libenzi
bcd0b235bf eventfd: improve support for semaphore-like behavior
People started using eventfd in a semaphore-like way where before they
were using pipes.

That is, counter-based resource access.  Where a "wait()" returns
immediately by decrementing the counter by one, if counter is greater than
zero.  Otherwise will wait.  And where a "post(count)" will add count to
the counter releasing the appropriate amount of waiters.  If eventfd the
"post" (write) part is fine, while the "wait" (read) does not dequeue 1,
but the whole counter value.

The problem with eventfd is that a read() on the fd returns and wipes the
whole counter, making the use of it as semaphore a little bit more
cumbersome.  You can do a read() followed by a write() of COUNTER-1, but
IMO it's pretty easy and cheap to make this work w/out extra steps.  This
patch introduces a new eventfd flag that tells eventfd to only dequeue 1
from the counter, allowing simple read/write to make it behave like a
semaphore.  Simple test here:

http://www.xmailserver.org/eventfd-sem.c

To be back-compatible with earlier kernels, userspace applications should
probe for the availability of this feature via

#ifdef EFD_SEMAPHORE
	fd = eventfd2 (CNT, EFD_SEMAPHORE);
	if (fd == -1 && errno == EINVAL)
		<fallback>
#else
		<fallback>
#endif

Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Cc: <linux-api@vger.kernel.org>
Tested-by: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Ulrich Drepper <drepper@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-01 08:59:20 -07:00
Tony Battersby
4f0989dbfa epoll: use real type instead of void *
eventpoll.c uses void * in one place for no obvious reason; change it to
use the real type instead.

Signed-off-by: Tony Battersby <tonyb@cybernetics.com>
Acked-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-01 08:59:20 -07:00
Tony Battersby
e057e15ff6 epoll: clean up ep_modify
ep_modify() doesn't need to set event.data from within the ep->lock
spinlock as the comment suggests.  The only place event.data is used is
ep_send_events_proc(), and this is protected by ep->mtx instead of
ep->lock.  Also update the comment for mutex_lock() at the top of
ep_scan_ready_list(), which mentions epoll_ctl(EPOLL_CTL_DEL) but not
epoll_ctl(EPOLL_CTL_MOD).

ep_modify() can also use spin_lock_irq() instead of spin_lock_irqsave().

Signed-off-by: Tony Battersby <tonyb@cybernetics.com>
Acked-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-01 08:59:19 -07:00
Tony Battersby
d1bc90dd5d epoll: remove unnecessary xchg
xchg in ep_unregister_pollwait() is unnecessary because it is protected by
either epmutex or ep->mtx (the same protection as ep_remove()).

If xchg was necessary, it would be insufficient to protect against
problems: if multiple concurrent calls to ep_unregister_pollwait() were
possible then a second caller that returns without doing anything because
nwait == 0 could return before the waitqueues are removed by the first
caller, which looks like it could lead to problematic races with
ep_poll_callback().

So remove xchg and add comments about the locking.

Signed-off-by: Tony Battersby <tonyb@cybernetics.com>
Acked-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-01 08:59:19 -07:00
Tony Battersby
d030588282 epoll: remember the event if epoll_wait returns -EFAULT
If epoll_wait returns -EFAULT, the event that was being returned when the
fault was encountered will be forgotten.  This is not a big deal since
EFAULT will happen only if a buggy userspace program passes in a bad
address, in which case what happens later usually doesn't matter.
However, it is easy to remember the event for later, and this patch makes
a simple change to do that.

Signed-off-by: Tony Battersby <tonyb@cybernetics.com>
Acked-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-01 08:59:19 -07:00
Tony Battersby
abff55cee1 epoll: don't use current in irq context
ep_call_nested() (formerly ep_poll_safewake()) uses "current" (without
dereferencing it) to detect callback recursion, but it may be called from
irq context where the use of current is generally discouraged.  It would
be better to use get_cpu() and put_cpu() to detect the callback recursion.

Signed-off-by: Tony Battersby <tonyb@cybernetics.com>
Acked-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-01 08:59:19 -07:00
Davide Libenzi
bb57c3edcd epoll: remove debugging code
Remove debugging code from epoll.  There's no need for it to be included
into mainline code.

Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-01 08:59:19 -07:00
Davide Libenzi
296e236e96 epoll: fix epoll's own poll (update)
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Cc: Pavel Pisa <pisa@cmp.felk.cvut.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-01 08:59:19 -07:00
Davide Libenzi
5071f97ec6 epoll: fix epoll's own poll
Fix a bug inside the epoll's f_op->poll() code, that returns POLLIN even
though there are no actual ready monitored fds.  The bug shows up if you
add an epoll fd inside another fd container (poll, select, epoll).

The problem is that callback-based wake ups used by epoll does not carry
(patches will follow, to fix this) any information about the events that
actually happened.  So the callback code, since it can't call the file*
->poll() inside the callback, chains the file* into a ready-list.

So, suppose you added an fd with EPOLLOUT only, and some data shows up on
the fd, the file* mapped by the fd will be added into the ready-list (via
wakeup callback).  During normal epoll_wait() use, this condition is
sorted out at the time we're actually able to call the file*'s
f_op->poll().

Inside the old epoll's f_op->poll() though, only a quick check
!list_empty(ready-list) was performed, and this could have led to
reporting POLLIN even though no ready fds would show up at a following
epoll_wait().  In order to correctly report the ready status for an epoll
fd, the ready-list must be checked to see if any really available fd+event
would be ready in a following epoll_wait().

Operation (calling f_op->poll() from inside f_op->poll()) that, like wake
ups, must be handled with care because of the fact that epoll fds can be
added to other epoll fds.

Test code:

/*
 *  epoll_test by Davide Libenzi (Simple code to test epoll internals)
 *  Copyright (C) 2008  Davide Libenzi
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 *  Davide Libenzi <davidel@xmailserver.org>
 *
 */

#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <signal.h>
#include <limits.h>
#include <poll.h>
#include <sys/epoll.h>
#include <sys/wait.h>

#define EPWAIT_TIMEO	(1 * 1000)
#ifndef POLLRDHUP
#define POLLRDHUP 0x2000
#endif

#define EPOLL_MAX_CHAIN	100L

#define EPOLL_TF_LOOP (1 << 0)

struct epoll_test_cfg {
	long size;
	long flags;
};

static int xepoll_create(int n) {
	int epfd;

	if ((epfd = epoll_create(n)) == -1) {
		perror("epoll_create");
		exit(2);
	}

	return epfd;
}

static void xepoll_ctl(int epfd, int cmd, int fd, struct epoll_event *evt) {
	if (epoll_ctl(epfd, cmd, fd, evt) < 0) {
		perror("epoll_ctl");
		exit(3);
	}
}

static void xpipe(int *fds) {
	if (pipe(fds)) {
		perror("pipe");
		exit(4);
	}
}

static pid_t xfork(void) {
	pid_t pid;

	if ((pid = fork()) == (pid_t) -1) {
		perror("pipe");
		exit(5);
	}

	return pid;
}

static int run_forked_proc(int (*proc)(void *), void *data) {
	int status;
	pid_t pid;

	if ((pid = xfork()) == 0)
		exit((*proc)(data));
	if (waitpid(pid, &status, 0) != pid) {
		perror("waitpid");
		return -1;
	}

	return WIFEXITED(status) ? WEXITSTATUS(status): -2;
}

static int check_events(int fd, int timeo) {
	struct pollfd pfd;

	fprintf(stdout, "Checking events for fd %d\n", fd);
	memset(&pfd, 0, sizeof(pfd));
	pfd.fd = fd;
	pfd.events = POLLIN | POLLOUT;
	if (poll(&pfd, 1, timeo) < 0) {
		perror("poll()");
		return 0;
	}
	if (pfd.revents & POLLIN)
		fprintf(stdout, "\tPOLLIN\n");
	if (pfd.revents & POLLOUT)
		fprintf(stdout, "\tPOLLOUT\n");
	if (pfd.revents & POLLERR)
		fprintf(stdout, "\tPOLLERR\n");
	if (pfd.revents & POLLHUP)
		fprintf(stdout, "\tPOLLHUP\n");
	if (pfd.revents & POLLRDHUP)
		fprintf(stdout, "\tPOLLRDHUP\n");

	return pfd.revents;
}

static int epoll_test_tty(void *data) {
	int epfd, ifd = fileno(stdin), res;
	struct epoll_event evt;

	if (check_events(ifd, 0) != POLLOUT) {
		fprintf(stderr, "Something is cooking on STDIN (%d)\n", ifd);
		return 1;
	}
	epfd = xepoll_create(1);
	fprintf(stdout, "Created epoll fd (%d)\n", epfd);
	memset(&evt, 0, sizeof(evt));
	evt.events = EPOLLIN;
	xepoll_ctl(epfd, EPOLL_CTL_ADD, ifd, &evt);
	if (check_events(epfd, 0) & POLLIN) {
		res = epoll_wait(epfd, &evt, 1, 0);
		if (res == 0) {
			fprintf(stderr, "Epoll fd (%d) is ready when it shouldn't!\n",
				epfd);
			return 2;
		}
	}

	return 0;
}

static int epoll_wakeup_chain(void *data) {
	struct epoll_test_cfg *tcfg = data;
	int i, res, epfd, bfd, nfd, pfds[2];
	pid_t pid;
	struct epoll_event evt;

	memset(&evt, 0, sizeof(evt));
	evt.events = EPOLLIN;

	epfd = bfd = xepoll_create(1);

	for (i = 0; i < tcfg->size; i++) {
		nfd = xepoll_create(1);
		xepoll_ctl(bfd, EPOLL_CTL_ADD, nfd, &evt);
		bfd = nfd;
	}
	xpipe(pfds);
	if (tcfg->flags & EPOLL_TF_LOOP)
	{
		xepoll_ctl(bfd, EPOLL_CTL_ADD, epfd, &evt);
		/*
		 * If we're testing for loop, we want that the wakeup
		 * triggered by the write to the pipe done in the child
		 * process, triggers a fake event. So we add the pipe
		 * read size with EPOLLOUT events. This will trigger
		 * an addition to the ready-list, but no real events
		 * will be there. The the epoll kernel code will proceed
		 * in calling f_op->poll() of the epfd, triggering the
		 * loop we want to test.
		 */
		evt.events = EPOLLOUT;
	}
	xepoll_ctl(bfd, EPOLL_CTL_ADD, pfds[0], &evt);

	/*
	 * The pipe write must come after the poll(2) call inside
	 * check_events(). This tests the nested wakeup code in
	 * fs/eventpoll.c:ep_poll_safewake()
	 * By having the check_events() (hence poll(2)) happens first,
	 * we have poll wait queue filled up, and the write(2) in the
	 * child will trigger the wakeup chain.
	 */
	if ((pid = xfork()) == 0) {
		sleep(1);
		write(pfds[1], "w", 1);
		exit(0);
	}

	res = check_events(epfd, 2000) & POLLIN;

	if (waitpid(pid, NULL, 0) != pid) {
		perror("waitpid");
		return -1;
	}

	return res;
}

static int epoll_poll_chain(void *data) {
	struct epoll_test_cfg *tcfg = data;
	int i, res, epfd, bfd, nfd, pfds[2];
	pid_t pid;
	struct epoll_event evt;

	memset(&evt, 0, sizeof(evt));
	evt.events = EPOLLIN;

	epfd = bfd = xepoll_create(1);

	for (i = 0; i < tcfg->size; i++) {
		nfd = xepoll_create(1);
		xepoll_ctl(bfd, EPOLL_CTL_ADD, nfd, &evt);
		bfd = nfd;
	}
	xpipe(pfds);
	if (tcfg->flags & EPOLL_TF_LOOP)
	{
		xepoll_ctl(bfd, EPOLL_CTL_ADD, epfd, &evt);
		/*
		 * If we're testing for loop, we want that the wakeup
		 * triggered by the write to the pipe done in the child
		 * process, triggers a fake event. So we add the pipe
		 * read size with EPOLLOUT events. This will trigger
		 * an addition to the ready-list, but no real events
		 * will be there. The the epoll kernel code will proceed
		 * in calling f_op->poll() of the epfd, triggering the
		 * loop we want to test.
		 */
		evt.events = EPOLLOUT;
	}
	xepoll_ctl(bfd, EPOLL_CTL_ADD, pfds[0], &evt);

	/*
	 * The pipe write mush come before the poll(2) call inside
	 * check_events(). This tests the nested f_op->poll calls code in
	 * fs/eventpoll.c:ep_eventpoll_poll()
	 * By having the pipe write(2) happen first, we make the kernel
	 * epoll code to load the ready lists, and the following poll(2)
	 * done inside check_events() will test nested poll code in
	 * ep_eventpoll_poll().
	 */
	if ((pid = xfork()) == 0) {
		write(pfds[1], "w", 1);
		exit(0);
	}
	sleep(1);
	res = check_events(epfd, 1000) & POLLIN;

	if (waitpid(pid, NULL, 0) != pid) {
		perror("waitpid");
		return -1;
	}

	return res;
}

int main(int ac, char **av) {
	int error;
	struct epoll_test_cfg tcfg;

	fprintf(stdout, "\n********** Testing TTY events\n");
	error = run_forked_proc(epoll_test_tty, NULL);
	fprintf(stdout, error == 0 ?
		"********** OK\n": "********** FAIL (%d)\n", error);

	tcfg.size = 3;
	tcfg.flags = 0;
	fprintf(stdout, "\n********** Testing short wakeup chain\n");
	error = run_forked_proc(epoll_wakeup_chain, &tcfg);
	fprintf(stdout, error == POLLIN ?
		"********** OK\n": "********** FAIL (%d)\n", error);

	tcfg.size = EPOLL_MAX_CHAIN;
	tcfg.flags = 0;
	fprintf(stdout, "\n********** Testing long wakeup chain (HOLD ON)\n");
	error = run_forked_proc(epoll_wakeup_chain, &tcfg);
	fprintf(stdout, error == 0 ?
		"********** OK\n": "********** FAIL (%d)\n", error);

	tcfg.size = 3;
	tcfg.flags = 0;
	fprintf(stdout, "\n********** Testing short poll chain\n");
	error = run_forked_proc(epoll_poll_chain, &tcfg);
	fprintf(stdout, error == POLLIN ?
		"********** OK\n": "********** FAIL (%d)\n", error);

	tcfg.size = EPOLL_MAX_CHAIN;
	tcfg.flags = 0;
	fprintf(stdout, "\n********** Testing long poll chain (HOLD ON)\n");
	error = run_forked_proc(epoll_poll_chain, &tcfg);
	fprintf(stdout, error == 0 ?
		"********** OK\n": "********** FAIL (%d)\n", error);

	tcfg.size = 3;
	tcfg.flags = EPOLL_TF_LOOP;
	fprintf(stdout, "\n********** Testing loopy wakeup chain (HOLD ON)\n");
	error = run_forked_proc(epoll_wakeup_chain, &tcfg);
	fprintf(stdout, error == 0 ?
		"********** OK\n": "********** FAIL (%d)\n", error);

	tcfg.size = 3;
	tcfg.flags = EPOLL_TF_LOOP;
	fprintf(stdout, "\n********** Testing loopy poll chain (HOLD ON)\n");
	error = run_forked_proc(epoll_poll_chain, &tcfg);
	fprintf(stdout, error == 0 ?
		"********** OK\n": "********** FAIL (%d)\n", error);

	return 0;
}

Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Cc: Pavel Pisa <pisa@cmp.felk.cvut.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-01 08:59:18 -07:00
Harvey Harrison
63cd885426 ntfs: remove private wrapper of endian helpers
The base versions handle constant folding now and are shorter than these
private wrappers, use them directly.

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Cc: Anton Altaparmakov <aia21@cantab.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-01 08:59:18 -07:00
Eric Sandeen
c2d7543851 filesystem freeze: allow SysRq emergency thaw to thaw frozen filesystems
Now that the filesystem freeze operation has been elevated to the VFS, and
is just an ioctl away, some sort of safety net for unintentionally frozen
root filesystems may be in order.

The timeout thaw originally proposed did not get merged, but perhaps
something like this would be useful in emergencies.

For example, freeze /path/to/mountpoint may freeze your root filesystem if
you forgot that you had that unmounted.

I chose 'j' as the last remaining character other than 'h' which is sort
of reserved for help (because help is generated on any unknown character).

I've tested this on a non-root fs with multiple (nested) freezers, as well
as on a system rendered unresponsive due to a frozen root fs.

[randy.dunlap@oracle.com: emergency thaw only if CONFIG_BLOCK enabled]
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Cc: Takashi Sato <t-sato@yk.jp.nec.com>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-01 08:59:17 -07:00
KAMEZAWA Hiroyuki
327c0e9686 vmscan: fix it to take care of nodemask
try_to_free_pages() is used for the direct reclaim of up to
SWAP_CLUSTER_MAX pages when watermarks are low.  The caller to
alloc_pages_nodemask() can specify a nodemask of nodes that are allowed to
be used but this is not passed to try_to_free_pages().  This can lead to
unnecessary reclaim of pages that are unusable by the caller and int the
worst case lead to allocation failure as progress was not been make where
it is needed.

This patch passes the nodemask used for alloc_pages_nodemask() to
try_to_free_pages().

Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-01 08:59:15 -07:00
Johannes Weiner
2678958e12 ramfs-nommu: use generic lru cache
Instead of open-coding the lru-list-add pagevec batching when expanding a
file mapping from zero, defer to the appropriate page cache function that
also takes care of adding the page to the lru list.

This is cleaner, saves code and reduces the stack footprint by 16 words
worth of pagevec.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: David Howells <dhowells@redhat.com>
Cc: Nick Piggin <npiggin@suse.de>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.com>
Cc: MinChan Kim <minchan.kim@gmail.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Cc: Greg Ungerer <gerg@snapgear.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-01 08:59:15 -07:00
Hugh Dickins
851a039cc5 mm: page_mkwrite change prototype to match fault: fix sysfs
Fix warnings and return values in sysfs bin_page_mkwrite(), fixing
fs/sysfs/bin.c: In function `bin_page_mkwrite':
fs/sysfs/bin.c:250: warning: passing argument 2 of `bb->vm_ops->page_mkwrite' from incompatible pointer type
fs/sysfs/bin.c: At top level:
fs/sysfs/bin.c:280: warning: initialization from incompatible pointer type

Expects to have my [PATCH next] sysfs: fix some bin_vm_ops errors

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: "Eric W. Biederman" <ebiederm@aristanetworks.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-01 08:59:14 -07:00
Nick Piggin
56a76f8275 fs: fix page_mkwrite error cases in core code and btrfs
page_mkwrite is called with neither the page lock nor the ptl held.  This
means a page can be concurrently truncated or invalidated out from
underneath it.  Callers are supposed to prevent truncate races themselves,
however previously the only thing they can do in case they hit one is to
raise a SIGBUS.  A sigbus is wrong for the case that the page has been
invalidated or truncated within i_size (eg.  hole punched).  Callers may
also have to perform memory allocations in this path, where again, SIGBUS
would be wrong.

The previous patch ("mm: page_mkwrite change prototype to match fault")
made it possible to properly specify errors.  Convert the generic buffer.c
code and btrfs to return sane error values (in the case of page removed
from pagecache, VM_FAULT_NOPAGE will cause the fault handler to exit
without doing anything, and the fault will be retried properly).

This fixes core code, and converts btrfs as a template/example.  All other
filesystems defining their own page_mkwrite should be fixed in a similar
manner.

Acked-by: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-01 08:59:14 -07:00
Nick Piggin
c2ec175c39 mm: page_mkwrite change prototype to match fault
Change the page_mkwrite prototype to take a struct vm_fault, and return
VM_FAULT_xxx flags.  There should be no functional change.

This makes it possible to return much more detailed error information to
the VM (and also can provide more information eg.  virtual_address to the
driver, which might be important in some special cases).

This is required for a subsequent fix.  And will also make it easier to
merge page_mkwrite() with fault() in future.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <joel.becker@oracle.com>
Cc: Artem Bityutskiy <dedekind@infradead.org>
Cc: Felix Blyakher <felixb@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-01 08:59:14 -07:00
Ravikiran G Thirumalai
2584e51732 mm: reintroduce and deprecate rlimit based access for SHM_HUGETLB
Allow non root users with sufficient mlock rlimits to be able to allocate
hugetlb backed shm for now.  Deprecate this though.  This is being
deprecated because the mlock based rlimit checks for SHM_HUGETLB is not
consistent with mmap based huge page allocations.

Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Reviewed-by: Mel Gorman <mel@csn.ul.ie>
Cc: William Lee Irwin III <wli@holomorphy.com>
Cc: Adam Litke <agl@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-01 08:59:12 -07:00
Ravikiran G Thirumalai
8a0bdec194 mm: fix SHM_HUGETLB to work with users in hugetlb_shm_group
Fix hugetlb subsystem so that non root users belonging to
hugetlb_shm_group can actually allocate hugetlb backed shm.

Currently non root users cannot even map one large page using SHM_HUGETLB
when they belong to the gid in /proc/sys/vm/hugetlb_shm_group.  This is
because allocation size is verified against RLIMIT_MEMLOCK resource limit
even if the user belongs to hugetlb_shm_group.

This patch
1. Fixes hugetlb subsystem so that users with CAP_IPC_LOCK and users
   belonging to hugetlb_shm_group don't need to be restricted with
   RLIMIT_MEMLOCK resource limits
2. This patch also disables mlock based rlimit checking (which will
   be reinstated and marked deprecated in a subsequent patch).

Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Reviewed-by: Mel Gorman <mel@csn.ul.ie>
Cc: William Lee Irwin III <wli@holomorphy.com>
Cc: Adam Litke <agl@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-01 08:59:12 -07:00
Edward Shishkin
e3a7cca1ef vfs: add/use account_page_dirtied()
Add a helper function account_page_dirtied().  Use that from two
callsites.  reiser4 adds a function which adds a third callsite.

Signed-off-by: Edward Shishkin<edward.shishkin@gmail.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-01 08:59:12 -07:00
Alexey Dobriyan
0f043a81eb proc tty: remove struct tty_operations::read_proc
struct tty_operations::proc_fops took it's place and there is one less
create_proc_read_entry() user now!

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-01 08:59:10 -07:00
Alexey Dobriyan
ae149b6bec proc tty: add struct tty_operations::proc_fops
Used for gradual switch of TTY drivers from using ->read_proc which helps
with gradual switch from ->read_proc for the whole tree.

As side effect, fix possible race condition when ->data initialized after
PDE is hooked into proc tree.

->proc_fops takes precedence over ->read_proc.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-01 08:59:08 -07:00
Dmitri Vorobiev
ced117c73e Remove two unneeded exports and make two symbols static in fs/mpage.c
Commit 29a814d2ee (vfs: add hooks for
ext4's delayed allocation support) exported the following functions

mpage_bio_submit()
__mpage_writepage()

for the benefit of ext4's delayed allocation support. Since commit
a1d6cc563b (ext4: Rework the
ext4_da_writepages() function), these functions are not used by the
ext4 driver anymore. However, the now unnecessary exports still
remain, and this patch removes those. Moreover, these two functions
can become static again.

The issue was spotted by namespacecheck.

Signed-off-by: Dmitri Vorobiev <dmitri.vorobiev@movial.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-04-01 07:38:54 -04:00