We can't fill i_size with rbytes at the fill_file_size stage without
adding additional checks for directories.  Notably, we want st_blocks
to remain 0 on directories so that 'du' still works.

Fill in i_blocks, i_size specially in ceph_getattr instead.
Signed-off-by: Sage Weil <sage@newdream.net>

Signed-off-by: Sage Weil <sage@newdream.net>

Mix the preferred osd (if any) into the placement seed that is fed into
the CRUSH object placement calculation.  This prevents all the placement
pgs from peering with the same osds.

Rev the osd client protocol with this change.
Signed-off-by: Sage Weil <sage@newdream.net>

Initialized bdi->ra_pages to enable readahead.  Use 512KB default.
Signed-off-by: Sage Weil <sage@newdream.net>

Cleanup only.
Signed-off-by: Sage Weil <sage@newdream.net>

Pass the front_len we need when pulling a message off a msgpool,
and WARN if it is greater than the pool's size.  Then try to
allocate a new message (to continue without failing).
Signed-off-by: Sage Weil <sage@newdream.net>

Defined a struct for the SUBSCRIBE_ACK, and use that to size
the msgpool.
Signed-off-by: Sage Weil <sage@newdream.net>

Previously we were flushing dirty caps by passing an extra flag
when traversing the delayed caps list.  Besides being a bit ugly,
that can also miss caps that are dirty but didn't result in a
cap requeue: notably, mark_caps_dirty().

Separate the flushing into a separate helper, and traverse the
cap_dirty list.

This also brings i_dirty_item in line with i_dirty_caps: we are
on the list IFF caps != 0.  We carry an inode ref IFF
dirty_caps|flushing_caps != 0.

Lose the unused return value from __ceph_mark_caps_dirty().
Signed-off-by: Sage Weil <sage@newdream.net>

Both callers of __mark_caps_flushing() do the same work; move it
into the helper.
Signed-off-by: Sage Weil <sage@newdream.net>

Writeback doesn't work without the bdi set, and writeback on
umount doesn't work if we unregister the bdi too early.
Signed-off-by: Sage Weil <sage@newdream.net>

This avoids the fugly pass by reference and makes the code a bit easier
to read.
Signed-off-by: Sage Weil <sage@newdream.net>

This makes it easier for individual message types to indicate
their particular encoding, and make future changes backward
compatible.
Signed-off-by: Sage Weil <sage@newdream.net>

Signed-off-by: Sage Weil <sage@newdream.net>

This lets us extend the format more easily.
Signed-off-by: Sage Weil <sage@newdream.net>

This tracks updates to code shared with userspace.
Signed-off-by: Sage Weil <sage@newdream.net>

The mon request headers now include session_mon information that must
be properly initialized.
Signed-off-by: Sage Weil <sage@newdream.net>

This ensures we don't submit the same request twice if we are kicking a
specific osd (as with an osd_reset), or when we hit a transient error and
resend.
Signed-off-by: Sage Weil <sage@newdream.net>

The peer_reset just takes longer (until we reconnect and discover the osd
dropped the session... which it will).
Signed-off-by: Sage Weil <sage@newdream.net>

Return an error and report a corrupt map instead of crying BUG().
Signed-off-by: Sage Weil <sage@newdream.net>

If an osd has failed or returned and a request has been sent twice, it's
possible to get a reply and unregister the request while the request
message is queued for delivery.  Since the message references the caller's
page vector, we need to revoke it before completing.
Signed-off-by: Sage Weil <sage@newdream.net>

The osd request submission path registers the request, drops and retakes
the request_mutex, then sends it to the OSD.  A racing kick_requests could
sent it during that interval, causing the same msg to be sent twice and
BUGing in the msgr.

Fix by only sending the message if it hasn't been touched by other
threads.
Signed-off-by: Sage Weil <sage@newdream.net>

Be conservative: renew subscription once half the interval has expired.

Do not reuse sub expiration to control hunting.
Signed-off-by: Sage Weil <sage@newdream.net>

A misplaced sizeof() around namelen was throwing things off.
Signed-off-by: Sage Weil <sage@newdream.net>

This avoids a divide by zero when the input and/or map are
malformed.
Signed-off-by: Sage Weil <sage@newdream.net>

Signed-off-by: Sage Weil <sage@newdream.net>

Kill the old git revision; print the ceph version and protocol
versions instead.
Signed-off-by: Sage Weil <sage@newdream.net>

Document files shared between kernel and user code trees.
Signed-off-by: Sage Weil <sage@newdream.net>

Kconfig options and Makefile.
Signed-off-by: Sage Weil <sage@newdream.net>

Basic state information is available via /sys/kernel/debug/ceph,
including instances of the client, fsids, current monitor, mds and osd
maps, outstanding server requests, and hooks to adjust debug levels.
Signed-off-by: Sage Weil <sage@newdream.net>

A few Ceph ioctls for getting and setting file layout (striping)
parameters, and learning the identity and network address of the OSD a
given region of a file is stored on.
Signed-off-by: Sage Weil <sage@newdream.net>

Basic NFS re-export support is included.  This mostly works.  However,
Ceph's MDS design precludes the ability to generate a (small)
filehandle that will be valid forever, so this is of limited utility.
Signed-off-by: Sage Weil <sage@newdream.net>

The msgpool is a basic mempool_t-like structure to preallocate
messages we expect to receive over the wire.  This ensures we have the
necessary memory preallocated to process replies to requests, or to
process unsolicited messages from various servers.
Signed-off-by: Sage Weil <sage@newdream.net>

A generic message passing library is used to communicate with all
other components in the Ceph file system.  The messenger library
provides ordered, reliable delivery of messages between two nodes in
the system.

This implementation is based on TCP.
Signed-off-by: Sage Weil <sage@newdream.net>

Ceph snapshots rely on client cooperation in determining which
operations apply to which snapshots, and appropriately flushing
snapshotted data and metadata back to the OSD and MDS clusters.
Because snapshots apply to subtrees of the file hierarchy and can be
created at any time, there is a fair bit of bookkeeping required to
make this work.

Portions of the hierarchy that belong to the same set of snapshots
are described by a single 'snap realm.'  A 'snap context' describes
the set of snapshots that exist for a given file or directory.
Signed-off-by: Sage Weil <sage@newdream.net>

The Ceph metadata servers control client access to inode metadata and
file data by issuing capabilities, granting clients permission to read
and/or write both inode field and file data to OSDs (storage nodes).
Each capability consists of a set of bits indicating which operations
are allowed.

If the client holds a *_SHARED cap, the client has a coherent value
that can be safely read from the cached inode.

In the case of a *_EXCL (exclusive) or FILE_WR capabilities, the client
is allowed to change inode attributes (e.g., file size, mtime), note
its dirty state in the ceph_cap, and asynchronously flush that
metadata change to the MDS.

In the event of a conflicting operation (perhaps by another client),
the MDS will revoke the conflicting client capabilities.

In order for a client to cache an inode, it must hold a capability
with at least one MDS server.  When inodes are released, release
notifications are batched and periodically sent en masse to the MDS
cluster to release server state.
Signed-off-by: Sage Weil <sage@newdream.net>

The monitor cluster is responsible for managing cluster membership
and state.  The monitor client handles what minimal interaction
the Ceph client has with it: checking for updated versions of the
MDS and OSD maps, getting statfs() information, and unmounting.
Signed-off-by: Sage Weil <sage@newdream.net>

CRUSH is a pseudorandom data distribution function designed to map
inputs onto a dynamic hierarchy of devices, while minimizing the
extent to which inputs are remapped when the devices are added or
removed.  It includes some features that are specifically useful for
storage, most notably the ability to map each input onto a set of N
devices that are separated across administrator-defined failure
domains.  CRUSH is used to distribute data across the cluster of Ceph
storage nodes.

More information about CRUSH can be found in this paper:

    http://www.ssrc.ucsc.edu/Papers/weil-sc06.pdfSigned-off-by: Sage Weil <sage@newdream.net>

The OSD client is responsible for reading and writing data from/to the
object storage pool.  This includes determining where objects are
stored in the cluster, and ensuring that requests are retried or
redirected in the event of a node failure or data migration.

If an OSD does not respond before a timeout expires, keepalive
messages are sent across the lossless, ordered communications channel
to ensure that any break in the TCP is discovered.  If the session
does reset, a reconnection is attempted and affected requests are
resent (by the message transport layer).
Signed-off-by: Sage Weil <sage@newdream.net>

The MDS (metadata server) client is responsible for submitting
requests to the MDS cluster and parsing the response.  We decide which
MDS to submit each request to based on cached information about the
current partition of the directory hierarchy across the cluster.  A
stateful session is opened with each MDS before we submit requests to
it, and a mutex is used to control the ordering of messages within
each session.

An MDS request may generate two responses.  The first indicates the
operation was a success and returns any result.  A second reply is
sent when the operation commits to disk.  Note that locking on the MDS
ensures that the results of updates are visible only to the updating
client before the operation commits.  Requests are linked to the
containing directory so that an fsync will wait for them to commit.

If an MDS fails and/or recovers, we resubmit requests as needed.  We
also reconnect existing capabilities to a recovering MDS to
reestablish that shared session state.  Old dentry leases are
invalidated.
Signed-off-by: Sage Weil <sage@newdream.net>

The ceph address space methods are concerned primarily with managing
the dirty page accounting in the inode, which (among other things)
must keep track of which snapshot context each page was dirtied in,
and ensure that dirty data is written out to the OSDs in snapshort
order.

A writepage() on a page that is not currently writeable due to
snapshot writeback ordering constraints is ignored (it was presumably
called from kswapd).
Signed-off-by: Sage Weil <sage@newdream.net>