Merge tag 'ofs-pull-tag-1' of git://git.kernel.org/pub/scm/linux/kernel/git/hubcap/linux

Pull orangefs filesystem from Mike Marshall.

This finally merges the long-pending orangefs filesystem, which has been
much cleaned up with input from Al Viro over the last six months.  From
the documentation file:

 "OrangeFS is an LGPL userspace scale-out parallel storage system.  It
  is ideal for large storage problems faced by HPC, BigData, Streaming
  Video, Genomics, Bioinformatics.

  Orangefs, originally called PVFS, was first developed in 1993 by Walt
  Ligon and Eric Blumer as a parallel file system for Parallel Virtual
  Machine (PVM) as part of a NASA grant to study the I/O patterns of
  parallel programs.

  Orangefs features include:

    - Distributes file data among multiple file servers
    - Supports simultaneous access by multiple clients
    - Stores file data and metadata on servers using local file system
      and access methods
    - Userspace implementation is easy to install and maintain
    - Direct MPI support
    - Stateless"

see Documentation/filesystems/orangefs.txt for more in-depth details.

* tag 'ofs-pull-tag-1' of git://git.kernel.org/pub/scm/linux/kernel/git/hubcap/linux: (174 commits)
  orangefs: fix orangefs_superblock locking
  orangefs: fix do_readv_writev() handling of error halfway through
  orangefs: have ->kill_sb() evict the VFS side of things first
  orangefs: sanitize ->llseek()
  orangefs-bufmap.h: trim unused junk
  orangefs: saner calling conventions for getting a slot
  orangefs_copy_{to,from}_bufmap(): don't pass bufmap pointer
  orangefs: get rid of readdir_handle_s
  ornagefs: ensure that truncate has an up to date inode size
  orangefs: move code which sets i_link to orangefs_inode_getattr
  orangefs: remove needless wrapper around GFP_KERNEL
  orangefs: remove wrapper around mutex_lock(&inode->i_mutex)
  orangefs: refactor inode type or link_target change detection
  orangefs: use new getattr for revalidate and remove old getattr
  orangefs: use new getattr in inode getattr and permission
  orangefs: use new orangefs_inode_getattr to get size in write and llseek
  orangefs: use new orangefs_inode_getattr to create new inodes
  orangefs: rename orangefs_inode_getattr to orangefs_inode_old_getattr
  orangefs: remove inode->i_lock wrapper
  orangefs: put register_chrdev immediately before register_filesystem
  ...

1 files changed, 406 insertions, 0 deletions

diff --git a/Documentation/filesystems/orangefs.txt b/Documentation/filesystems/orangefs.txt
new file mode 100644
index 000000000000..e1a0056a365f
--- /dev/null
+++ b/Documentation/filesystems/orangefs.txt
@@ -0,0 +1,406 @@
+ORANGEFS
+========
+
+OrangeFS is an LGPL userspace scale-out parallel storage system. It is ideal
+for large storage problems faced by HPC, BigData, Streaming Video,
+Genomics, Bioinformatics.
+
+Orangefs, originally called PVFS, was first developed in 1993 by
+Walt Ligon and Eric Blumer as a parallel file system for Parallel
+Virtual Machine (PVM) as part of a NASA grant to study the I/O patterns
+of parallel programs.
+
+Orangefs features include:
+
+  * Distributes file data among multiple file servers
+  * Supports simultaneous access by multiple clients
+  * Stores file data and metadata on servers using local file system
+    and access methods
+  * Userspace implementation is easy to install and maintain
+  * Direct MPI support
+  * Stateless
+
+
+MAILING LIST
+============
+
+http://beowulf-underground.org/mailman/listinfo/pvfs2-users
+
+
+DOCUMENTATION
+=============
+
+http://www.orangefs.org/documentation/
+
+
+USERSPACE FILESYSTEM SOURCE
+===========================
+
+http://www.orangefs.org/download
+
+Orangefs versions prior to 2.9.3 would not be compatible with the
+upstream version of the kernel client.
+
+
+BUILDING THE USERSPACE FILESYSTEM ON A SINGLE SERVER
+====================================================
+
+When Orangefs is upstream, "--with-kernel" shouldn't be needed, but
+until then the path to where the kernel with the Orangefs kernel client
+patch was built is needed to ensure that pvfs2-client-core (the bridge
+between kernel space and user space) will build properly. You can omit
+--prefix if you don't care that things are sprinkled around in
+/usr/local.
+
+./configure --prefix=/opt/ofs --with-kernel=/path/to/orangefs/kernel
+
+make
+
+make install
+
+Create an orangefs config file:
+/opt/ofs/bin/pvfs2-genconfig /etc/pvfs2.conf
+
+  for "Enter hostnames", use the hostname, don't let it default to
+  localhost.
+
+create a pvfs2tab file in /etc:
+cat /etc/pvfs2tab
+tcp://myhostname:3334/orangefs /mymountpoint pvfs2 defaults,noauto 0 0
+
+create the mount point you specified in the tab file if needed:
+mkdir /mymountpoint
+
+bootstrap the server:
+/opt/ofs/sbin/pvfs2-server /etc/pvfs2.conf -f
+
+start the server:
+/opt/osf/sbin/pvfs2-server /etc/pvfs2.conf
+
+Now the server is running. At this point you might like to
+prove things are working with:
+
+/opt/osf/bin/pvfs2-ls /mymountpoint
+
+You might not want to enforce selinux, it doesn't seem to matter by
+linux 3.11...
+
+If stuff seems to be working, turn on the client core:
+/opt/osf/sbin/pvfs2-client -p /opt/osf/sbin/pvfs2-client-core
+
+Mount your filesystem.
+mount -t pvfs2 tcp://myhostname:3334/orangefs /mymountpoint
+
+
+OPTIONS
+=======
+
+The following mount options are accepted:
+
+  acl
+    Allow the use of Access Control Lists on files and directories.
+
+  intr
+    Some operations between the kernel client and the user space
+    filesystem can be interruptible, such as changes in debug levels
+    and the setting of tunable parameters.
+
+  local_lock
+    Enable posix locking from the perspective of "this" kernel. The
+    default file_operations lock action is to return ENOSYS. Posix
+    locking kicks in if the filesystem is mounted with -o local_lock.
+    Distributed locking is being worked on for the future.
+
+
+DEBUGGING
+=========
+
+If you want the debug (GOSSIP) statements in a particular
+source file (inode.c for example) go to syslog:
+
+  echo inode > /sys/kernel/debug/orangefs/kernel-debug
+
+No debugging (the default):
+
+  echo none > /sys/kernel/debug/orangefs/kernel-debug
+
+Debugging from several source files:
+
+  echo inode,dir > /sys/kernel/debug/orangefs/kernel-debug
+
+All debugging:
+
+  echo all > /sys/kernel/debug/orangefs/kernel-debug
+
+Get a list of all debugging keywords:
+
+  cat /sys/kernel/debug/orangefs/debug-help
+
+
+PROTOCOL BETWEEN KERNEL MODULE AND USERSPACE
+============================================
+
+Orangefs is a user space filesystem and an associated kernel module.
+We'll just refer to the user space part of Orangefs as "userspace"
+from here on out. Orangefs descends from PVFS, and userspace code
+still uses PVFS for function and variable names. Userspace typedefs
+many of the important structures. Function and variable names in
+the kernel module have been transitioned to "orangefs", and The Linux
+Coding Style avoids typedefs, so kernel module structures that
+correspond to userspace structures are not typedefed.
+
+The kernel module implements a pseudo device that userspace
+can read from and write to. Userspace can also manipulate the
+kernel module through the pseudo device with ioctl.
+
+THE BUFMAP:
+
+At startup userspace allocates two page-size-aligned (posix_memalign)
+mlocked memory buffers, one is used for IO and one is used for readdir
+operations. The IO buffer is 41943040 bytes and the readdir buffer is
+4194304 bytes. Each buffer contains logical chunks, or partitions, and
+a pointer to each buffer is added to its own PVFS_dev_map_desc structure
+which also describes its total size, as well as the size and number of
+the partitions.
+
+A pointer to the IO buffer's PVFS_dev_map_desc structure is sent to a
+mapping routine in the kernel module with an ioctl. The structure is
+copied from user space to kernel space with copy_from_user and is used
+to initialize the kernel module's "bufmap" (struct orangefs_bufmap), which
+then contains:
+
+  * refcnt - a reference counter
+  * desc_size - PVFS2_BUFMAP_DEFAULT_DESC_SIZE (4194304) - the IO buffer's
+    partition size, which represents the filesystem's block size and
+    is used for s_blocksize in super blocks.
+  * desc_count - PVFS2_BUFMAP_DEFAULT_DESC_COUNT (10) - the number of
+    partitions in the IO buffer.
+  * desc_shift - log2(desc_size), used for s_blocksize_bits in super blocks.
+  * total_size - the total size of the IO buffer.
+  * page_count - the number of 4096 byte pages in the IO buffer.
+  * page_array - a pointer to page_count * (sizeof(struct page*)) bytes
+    of kcalloced memory. This memory is used as an array of pointers
+    to each of the pages in the IO buffer through a call to get_user_pages.
+  * desc_array - a pointer to desc_count * (sizeof(struct orangefs_bufmap_desc))
+    bytes of kcalloced memory. This memory is further intialized:
+
+      user_desc is the kernel's copy of the IO buffer's ORANGEFS_dev_map_desc
+      structure. user_desc->ptr points to the IO buffer.
+
+      pages_per_desc = bufmap->desc_size / PAGE_SIZE
+      offset = 0
+
+        bufmap->desc_array[0].page_array = &bufmap->page_array[offset]
+        bufmap->desc_array[0].array_count = pages_per_desc = 1024
+        bufmap->desc_array[0].uaddr = (user_desc->ptr) + (0 * 1024 * 4096)
+        offset += 1024
+                           .
+                           .
+                           .
+        bufmap->desc_array[9].page_array = &bufmap->page_array[offset]
+        bufmap->desc_array[9].array_count = pages_per_desc = 1024
+        bufmap->desc_array[9].uaddr = (user_desc->ptr) +
+                                               (9 * 1024 * 4096)
+        offset += 1024
+
+  * buffer_index_array - a desc_count sized array of ints, used to
+    indicate which of the IO buffer's partitions are available to use.
+  * buffer_index_lock - a spinlock to protect buffer_index_array during update.
+  * readdir_index_array - a five (ORANGEFS_READDIR_DEFAULT_DESC_COUNT) element
+    int array used to indicate which of the readdir buffer's partitions are
+    available to use.
+  * readdir_index_lock - a spinlock to protect readdir_index_array during
+    update.
+
+OPERATIONS:
+
+The kernel module builds an "op" (struct orangefs_kernel_op_s) when it
+needs to communicate with userspace. Part of the op contains the "upcall"
+which expresses the request to userspace. Part of the op eventually
+contains the "downcall" which expresses the results of the request.
+
+The slab allocator is used to keep a cache of op structures handy.
+
+At init time the kernel module defines and initializes a request list
+and an in_progress hash table to keep track of all the ops that are
+in flight at any given time.
+
+Ops are stateful:
+
+ * unknown  - op was just initialized
+ * waiting  - op is on request_list (upward bound)
+ * inprogr  - op is in progress (waiting for downcall)
+ * serviced - op has matching downcall; ok
+ * purged   - op has to start a timer since client-core
+              exited uncleanly before servicing op
+ * given up - submitter has given up waiting for it
+
+When some arbitrary userspace program needs to perform a
+filesystem operation on Orangefs (readdir, I/O, create, whatever)
+an op structure is initialized and tagged with a distinguishing ID
+number. The upcall part of the op is filled out, and the op is
+passed to the "service_operation" function.
+
+Service_operation changes the op's state to "waiting", puts
+it on the request list, and signals the Orangefs file_operations.poll
+function through a wait queue. Userspace is polling the pseudo-device
+and thus becomes aware of the upcall request that needs to be read.
+
+When the Orangefs file_operations.read function is triggered, the
+request list is searched for an op that seems ready-to-process.
+The op is removed from the request list. The tag from the op and
+the filled-out upcall struct are copy_to_user'ed back to userspace.
+
+If any of these (and some additional protocol) copy_to_users fail,
+the op's state is set to "waiting" and the op is added back to
+the request list. Otherwise, the op's state is changed to "in progress",
+and the op is hashed on its tag and put onto the end of a list in the
+in_progress hash table at the index the tag hashed to.
+
+When userspace has assembled the response to the upcall, it
+writes the response, which includes the distinguishing tag, back to
+the pseudo device in a series of io_vecs. This triggers the Orangefs
+file_operations.write_iter function to find the op with the associated
+tag and remove it from the in_progress hash table. As long as the op's
+state is not "canceled" or "given up", its state is set to "serviced".
+The file_operations.write_iter function returns to the waiting vfs,
+and back to service_operation through wait_for_matching_downcall.
+
+Service operation returns to its caller with the op's downcall
+part (the response to the upcall) filled out.
+
+The "client-core" is the bridge between the kernel module and
+userspace. The client-core is a daemon. The client-core has an
+associated watchdog daemon. If the client-core is ever signaled
+to die, the watchdog daemon restarts the client-core. Even though
+the client-core is restarted "right away", there is a period of
+time during such an event that the client-core is dead. A dead client-core
+can't be triggered by the Orangefs file_operations.poll function.
+Ops that pass through service_operation during a "dead spell" can timeout
+on the wait queue and one attempt is made to recycle them. Obviously,
+if the client-core stays dead too long, the arbitrary userspace processes
+trying to use Orangefs will be negatively affected. Waiting ops
+that can't be serviced will be removed from the request list and
+have their states set to "given up". In-progress ops that can't 
+be serviced will be removed from the in_progress hash table and
+have their states set to "given up".
+
+Readdir and I/O ops are atypical with respect to their payloads.
+
+  - readdir ops use the smaller of the two pre-allocated pre-partitioned
+    memory buffers. The readdir buffer is only available to userspace.
+    The kernel module obtains an index to a free partition before launching
+    a readdir op. Userspace deposits the results into the indexed partition
+    and then writes them to back to the pvfs device.
+
+  - io (read and write) ops use the larger of the two pre-allocated
+    pre-partitioned memory buffers. The IO buffer is accessible from
+    both userspace and the kernel module. The kernel module obtains an
+    index to a free partition before launching an io op. The kernel module
+    deposits write data into the indexed partition, to be consumed
+    directly by userspace. Userspace deposits the results of read
+    requests into the indexed partition, to be consumed directly
+    by the kernel module.
+
+Responses to kernel requests are all packaged in pvfs2_downcall_t
+structs. Besides a few other members, pvfs2_downcall_t contains a
+union of structs, each of which is associated with a particular
+response type.
+
+The several members outside of the union are:
+ - int32_t type - type of operation.
+ - int32_t status - return code for the operation.
+ - int64_t trailer_size - 0 unless readdir operation.
+ - char *trailer_buf - initialized to NULL, used during readdir operations.
+
+The appropriate member inside the union is filled out for any
+particular response.
+
+  PVFS2_VFS_OP_FILE_IO
+    fill a pvfs2_io_response_t
+
+  PVFS2_VFS_OP_LOOKUP
+    fill a PVFS_object_kref
+
+  PVFS2_VFS_OP_CREATE
+    fill a PVFS_object_kref
+
+  PVFS2_VFS_OP_SYMLINK
+    fill a PVFS_object_kref
+
+  PVFS2_VFS_OP_GETATTR
+    fill in a PVFS_sys_attr_s (tons of stuff the kernel doesn't need)
+    fill in a string with the link target when the object is a symlink.
+
+  PVFS2_VFS_OP_MKDIR
+    fill a PVFS_object_kref
+
+  PVFS2_VFS_OP_STATFS
+    fill a pvfs2_statfs_response_t with useless info <g>. It is hard for
+    us to know, in a timely fashion, these statistics about our
+    distributed network filesystem. 
+
+  PVFS2_VFS_OP_FS_MOUNT
+    fill a pvfs2_fs_mount_response_t which is just like a PVFS_object_kref
+    except its members are in a different order and "__pad1" is replaced
+    with "id".
+
+  PVFS2_VFS_OP_GETXATTR
+    fill a pvfs2_getxattr_response_t
+
+  PVFS2_VFS_OP_LISTXATTR
+    fill a pvfs2_listxattr_response_t
+
+  PVFS2_VFS_OP_PARAM
+    fill a pvfs2_param_response_t
+
+  PVFS2_VFS_OP_PERF_COUNT
+    fill a pvfs2_perf_count_response_t
+
+  PVFS2_VFS_OP_FSKEY
+    file a pvfs2_fs_key_response_t
+
+  PVFS2_VFS_OP_READDIR
+    jamb everything needed to represent a pvfs2_readdir_response_t into
+    the readdir buffer descriptor specified in the upcall.
+
+Userspace uses writev() on /dev/pvfs2-req to pass responses to the requests
+made by the kernel side.
+
+A buffer_list containing:
+  - a pointer to the prepared response to the request from the
+    kernel (struct pvfs2_downcall_t).
+  - and also, in the case of a readdir request, a pointer to a
+    buffer containing descriptors for the objects in the target
+    directory.
+... is sent to the function (PINT_dev_write_list) which performs
+the writev.
+
+PINT_dev_write_list has a local iovec array: struct iovec io_array[10];
+
+The first four elements of io_array are initialized like this for all
+responses:
+
+  io_array[0].iov_base = address of local variable "proto_ver" (int32_t)
+  io_array[0].iov_len = sizeof(int32_t)
+
+  io_array[1].iov_base = address of global variable "pdev_magic" (int32_t)
+  io_array[1].iov_len = sizeof(int32_t)
+  
+  io_array[2].iov_base = address of parameter "tag" (PVFS_id_gen_t)
+  io_array[2].iov_len = sizeof(int64_t)
+
+  io_array[3].iov_base = address of out_downcall member (pvfs2_downcall_t)
+                         of global variable vfs_request (vfs_request_t)
+  io_array[3].iov_len = sizeof(pvfs2_downcall_t)
+
+Readdir responses initialize the fifth element io_array like this:
+
+  io_array[4].iov_base = contents of member trailer_buf (char *)
+                         from out_downcall member of global variable
+                         vfs_request
+  io_array[4].iov_len = contents of member trailer_size (PVFS_size)
+                        from out_downcall member of global variable
+                        vfs_request
+  
+