ceph_writepages_start() reads inode->i_size in two places. It can get
different values between successive read, because truncate can change
inode->i_size at any time. The race can lead to mismatch between data
length of osd request and pages marked as writeback. When osd request
finishes, it clear writeback page according to its data length. So
some pages can be left in writeback state forever. The fix is only
read inode->i_size once, save its value to a local variable and use
the local variable when i_size is needed.
Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Alex Elder <elder@inktank.com>
copy write checks in __generic_file_aio_write to ceph_aio_write.
To make these checks cover sync write path.
Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Alex Elder <elder@inktank.com>
There is deadlock as illustrated bellow. The fix is taking i_mutex
before getting Fw cap reference.
write truncate MDS
--------------------- -------------------- --------------
get Fw cap
lock i_mutex
lock i_mutex (blocked)
request setattr.size ->
<- revoke Fw cap
Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Alex Elder <elder@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
An osd request currently has two callbacks. They inform the
initiator of the request when we've received confirmation for the
target osd that a request was received, and when the osd indicates
all changes described by the request are durable.
The only time the second callback is used is in the ceph file system
for a synchronous write. There's a race that makes some handling of
this case unsafe. This patch addresses this problem. The error
handling for this callback is also kind of gross, and this patch
changes that as well.
In ceph_sync_write(), if a safe callback is requested we want to add
the request on the ceph inode's unsafe items list. Because items on
this list must have their tid set (by ceph_osd_start_request()), the
request added *after* the call to that function returns. The
problem with this is that there's a race between starting the
request and adding it to the unsafe items list; the request may
already be complete before ceph_sync_write() even begins to put it
on the list.
To address this, we change the way the "safe" callback is used.
Rather than just calling it when the request is "safe", we use it to
notify the initiator the bounds (start and end) of the period during
which the request is *unsafe*. So the initiator gets notified just
before the request gets sent to the osd (when it is "unsafe"), and
again when it's known the results are durable (it's no longer
unsafe). The first call will get made in __send_request(), just
before the request message gets sent to the messenger for the first
time. That function is only called by __send_queued(), which is
always called with the osd client's request mutex held.
We then have this callback function insert the request on the ceph
inode's unsafe list when we're told the request is unsafe. This
will avoid the race because this call will be made under protection
of the osd client's request mutex. It also nicely groups the setup
and cleanup of the state associated with managing unsafe requests.
The name of the "safe" callback field is changed to "unsafe" to
better reflect its new purpose. It has a Boolean "unsafe" parameter
to indicate whether the request is becoming unsafe or is now safe.
Because the "msg" parameter wasn't used, we drop that.
This resolves the original problem reportedin:
http://tracker.ceph.com/issues/4706
Reported-by: Yan, Zheng <zheng.z.yan@intel.com>
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Sage Weil <sage@inktank.com>
In ceph_sync_write(), if a safe callback is supplied with a request,
and an error is returned by ceph_osdc_wait_request(), a block of
code is executed to remove the request from the unsafe writes list
and drop references to capabilities acquired just prior to a call to
ceph_osdc_wait_request().
The only function used for this callback is sync_write_commit(),
and it does *exactly* what that block of error handling code does.
Now in ceph_osdc_wait_request(), if an error occurs (due to an
interupt during a wait_for_completion_interruptible() call),
complete_request() gets called, and that calls the request's
safe_callback method if it's defined.
So this means that this cleanup activity gets called twice in this
case, which is erroneous (and in fact leads to a crash).
Fix this by just letting the osd client handle the cleanup in
the event of an interrupt.
This resolves one problem mentioned in:
http://tracker.ceph.com/issues/4706
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Yan, Zheng <zheng.z.yan@intel.com>
We don't need to use up entropy to choose an mds,
so use prandom_u32() to get a pseudo-random number.
Also, we don't need to choose a random mds if only
one mds is available, so add special casing for the
common case.
Fixes http://tracker.ceph.com/issues/3579
Signed-off-by: Sam Lang <sam.lang@inktank.com>
Reviewed-by: Greg Farnum <greg@inktank.com>
Reviewed-by: Alex Elder <elder@inktank.com>
Change the names of the functions that put data on a pagelist to
reflect that we're adding to whatever's already there rather than
just setting it to the one thing. Currently only one data item is
ever added to a message, but that's about to change.
This resolves:
http://tracker.ceph.com/issues/2770
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
This ends up being a rather large patch but what it's doing is
somewhat straightforward.
Basically, this is replacing two calls with one. The first of the
two calls is initializing a struct ceph_osd_data with data (either a
page array, a page list, or a bio list); the second is setting an
osd request op so it associates that data with one of the op's
parameters. In place of those two will be a single function that
initializes the op directly.
That means we sort of fan out a set of the needed functions:
- extent ops with pages data
- extent ops with pagelist data
- extent ops with bio list data
and
- class ops with page data for receiving a response
We also have define another one, but it's only used internally:
- class ops with pagelist data for request parameters
Note that we *still* haven't gotten rid of the osd request's
r_data_in and r_data_out fields. All the osd ops refer to them for
their data. For now, these data fields are pointers assigned to the
appropriate r_data_* field when these new functions are called.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
An osd request now holds all of its source op structures, and every
place that initializes one of these is in fact initializing one
of the entries in the the osd request's array.
So rather than supplying the address of the op to initialize, have
caller specify the osd request and an indication of which op it
would like to initialize. This better hides the details the
op structure (and faciltates moving the data pointers they use).
Since osd_req_op_init() is a common routine, and it's not used
outside the osd client code, give it static scope. Also make
it return the address of the specified op (so all the other
init routines don't have to repeat that code).
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
An extent type osd operation currently implies that there will
be corresponding data supplied in the data portion of the request
(for write) or response (for read) message. Similarly, an osd class
method operation implies a data item will be supplied to receive
the response data from the operation.
Add a ceph_osd_data pointer to each of those structures, and assign
it to point to eithre the incoming or the outgoing data structure in
the osd message. The data is not always available when an op is
initially set up, so add two new functions to allow setting them
after the op has been initialized.
Begin to make use of the data item pointer available in the osd
operation rather than the request data in or out structure in
places where it's convenient. Add some assertions to verify
pointers are always set the way they're expected to be.
This is a sort of stepping stone toward really moving the data
into the osd request ops, to allow for some validation before
making that jump.
This is the first in a series of patches that resolve:
http://tracker.ceph.com/issues/4657
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
An osd request keeps a pointer to the osd operations (ops) array
that it builds in its request message.
In order to allow each op in the array to have its own distinct
data, we will need to keep track of each op's data, and that
information does not go over the wire.
As long as we're tracking the data we might as well just track the
entire (source) op definition for each of the ops. And if we're
doing that, we'll have no more need to keep a pointer to the
wire-encoded version.
This patch makes the array of source ops be kept with the osd
request structure, and uses that instead of the version encoded in
the message in places where that was previously used. The array
will be embedded in the request structure, and the maximum number of
ops we ever actually use is currently 2. So reduce CEPH_OSD_MAX_OP
to 2 to reduce the size of the structure.
The result of doing this sort of ripples back up, and as a result
various function parameters and local variables become unnecessary.
Make r_num_ops be unsigned, and move the definition of struct
ceph_osd_req_op earlier to ensure it's defined where needed.
It does not yet add per-op data, that's coming soon.
This resolves:
http://tracker.ceph.com/issues/4656
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
These are very small changes that make use osd_data local pointers
as shorthands for structures being operated on.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Define and use functions that encapsulate the initializion of a
ceph_osd_data structure.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Hold off building the osd request message in ceph_writepages_start()
until just before it will be submitted to the osd client for
execution.
We'll still create the request and allocate the page pointer array
after we learn we have at least one page to write. A local variable
will be used to keep track of the allocated array of pages. Wait
until just before submitting the request for assigning that page
array pointer to the request message.
Create ands use a new function osd_req_op_extent_update() whose
purpose is to serve this one spot where the length value supplied
when an osd request's op was initially formatted might need to get
changed (reduced, never increased) before submitting the request.
Previously, ceph_writepages_start() assigned the message header's
data length because of this update. That's no longer necessary,
because ceph_osdc_build_request() will recalculate the right
value to use based on the content of the ops in the request.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Defer building the osd request until just before submitting it in
all callers except ceph_writepages_start(). (That caller will be
handed in the next patch.)
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
There is a helper function alloc_page_vec() that, despite its
generic sounding name depends heavily on an osd request structure
being populated with certain information.
There is only one place this function is used, and it ends up
being a bit simpler to just open code what it does, so get
rid of the helper.
The real motivation for this is deferring building the of the osd
request message, and this is a step in that direction.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Mostly for readability, define ceph_writepages_osd_request() and
use it to allocate the osd request for ceph_writepages_start().
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
This patch moves the call to ceph_osdc_build_request() out of
ceph_osdc_new_request() and into its caller.
This is in order to defer formatting osd operation information into
the request message until just before request is started.
The only unusual (ab)user of ceph_osdc_build_request() is
ceph_writepages_start(), where the final length of write request may
change (downward) based on the current inode size or the oldest
snapshot context with dirty data for the inode.
The remaining callers don't change anything in the request after has
been built.
This means the ops array is now supplied by the caller. It also
means there is no need to pass the mtime to ceph_osdc_new_request()
(it gets provided to ceph_osdc_build_request()). And rather than
passing a do_sync flag, have the number of ops in the ops array
supplied imply adding a second STARTSYNC operation after the READ or
WRITE requested.
This and some of the patches that follow are related to having the
messenger (only) be responsible for filling the content of the
message header, as described here:
http://tracker.ceph.com/issues/4589
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
There's one spot in ceph_writepages_start() that open-codes what
page_offset() does safely. Use the macro so we don't have to worry
about wrapping.
This resolves:
http://tracker.ceph.com/issues/4648
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
In create_fs_client() a memory pool is set up be used for arrays of
pages that might be needed in ceph_writepages_start() if memory is
tight. There are two problems with the way it's initialized:
- The size provided is the number of pages we want in the
array, but it should be the number of bytes required for
that many page pointers.
- The number of pages computed can end up being 0, while we
will always need at least one page.
This patch fixes both of these problems.
This resolves the two simple problems defined in:
http://tracker.ceph.com/issues/4603
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Use wrapper functions that check whether the auth op exists so that callers
do not need a bunch of conditional checks. Simplifies the external
interface.
Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Alex Elder <elder@inktank.com>
Currently the messenger calls out to a get_authorizer con op, which will
create a new authorizer if it doesn't yet have one. In the meantime, when
we rotate our service keys, the authorizer doesn't get updated. Eventually
it will be rejected by the server on a new connection attempt and get
invalidated, and we will then rebuild a new authorizer, but this is not
ideal.
Instead, if we do have an authorizer, call a new update_authorizer op that
will verify that the current authorizer is using the latest secret. If it
is not, we will build a new one that does. This avoids the transient
failure.
This fixes one of the sorry sequence of events for bug
http://tracker.ceph.com/issues/4282
Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Alex Elder <elder@inktank.com>
We should advance the user data pointer by _len_ instead of _written_.
_len_ is the data length written in each iteration while _written_ is the
accumulated data length we have writtent out.
Signed-off-by: Henry C Chang <henry.cy.chang@gmail.com>
Reviewed-by: Greg Farnum <greg@inktank.com>
Tested-by: Sage Weil <sage@inktank.com>
Current ceph code tracks directory's completeness in two places.
ceph_readdir() checks i_release_count to decide if it can set the
I_COMPLETE flag in i_ceph_flags. All other places check the I_COMPLETE
flag. This indirection introduces locking complexity.
This patch adds a new variable i_complete_count to ceph_inode_info.
Set i_release_count's value to it when marking a directory complete.
By comparing the two variables, we know if a directory is complete
Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Change it so we only assign outgoing data information for messages
if there is outgoing data to send.
This then allows us to add a few more (currently commented-out)
assertions.
This is related to:
http://tracker.ceph.com/issues/4284
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Greg Farnum <greg@inktank.com>
Define ceph_msg_data_set_pagelist(), ceph_msg_data_set_bio(), and
ceph_msg_data_set_trail() to clearly abstract the assignment of the
remaining data-related fields in a ceph message structure. Use the
new functions in the osd client and mds client.
This partially resolves:
http://tracker.ceph.com/issues/4263
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
When setting page array information for message data, provide the
byte length rather than the page count ceph_msg_data_set_pages().
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Define a function ceph_msg_data_set_pages(), which more clearly
abstracts the assignment page-related fields for data in a ceph
message structure. Use this new function in the osd client and mds
client.
Ideally, these fields would never be set more than once (with
BUG_ON() calls to guarantee that). At the moment though the osd
client sets these every time it receives a message, and in the event
of a communication problem this can happen more than once. (This
will be resolved shortly, but setting up these helpers first makes
it all a bit easier to work with.)
Rearrange the field order in a ceph_msg structure to group those
that are used to define the possible data payloads.
This partially resolves:
http://tracker.ceph.com/issues/4263
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Record the byte count for an osd request rather than the page count.
The number of pages can always be derived from the byte count (and
alignment/offset) but the reverse is not true.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
An osd request defines information about where data to be read
should be placed as well as where data to write comes from.
Currently these are represented by common fields.
Keep information about data for writing separate from data to be
read by splitting these into data_in and data_out fields.
This is the key patch in this whole series, in that it actually
identifies which osd requests generate outgoing data and which
generate incoming data. It's less obvious (currently) that an osd
CALL op generates both outgoing and incoming data; that's the focus
of some upcoming work.
This resolves:
http://tracker.ceph.com/issues/4127
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
An osd request uses either pages or a bio list for its data. Use a
union to record information about the two, and add a data type
tag to select between them.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Pull the fields in an osd request structure that define the data for
the request out into a separate structure.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Currently ceph_osdc_new_request() assigns an osd request's
r_num_pages and r_alignment fields. The only thing it does
after that is call ceph_osdc_build_request(), and that doesn't
need those fields to be assigned.
Move the assignment of those fields out of ceph_osdc_new_request()
and into its caller. As a result, the page_align parameter is no
longer used, so get rid of it.
Note that in ceph_sync_write(), the value for req->r_num_pages had
already been calculated earlier (as num_pages, and fortunately
it was computed the same way). So don't bother recomputing it,
but because it's not needed earlier, move that calculation after the
call to ceph_osdc_new_request(). Hold off making the assignment to
r_alignment, doing it instead r_pages and r_num_pages are
getting set.
Similarly, in start_read(), nr_pages already holds the number of
pages in the array (and is calculated the same way), so there's no
need to recompute it. Move the assignment of the page alignment
down with the others there as well.
This and the next few patches are preparation work for:
http://tracker.ceph.com/issues/4127
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
(This is being reposted. The first one had a problem because it
erroneously added a similar change elsewhere; that change has been
dropped.)
The next patch in this series points out that the calculation for
the number of pages in an osd request is getting done twice. It
is not obvious, but the result of both calculations is identical.
This patch simplifies one of them--as a separate step--to make
it clear that the transformation in the next patch is valid.
In ceph_sync_write() there is some magic that computes page_align
for an osd request. But a little analysis shows it can be
simplified.
First, we have:
io_align = pos & ~PAGE_MASK;
which is used here:
page_align = (pos - io_align + buf_align) & ~PAGE_MASK;
Note (pos - io_align) simply rounds "pos" down to the nearest multiple
of the page size.
We also have:
buf_align = (unsigned long)data & ~PAGE_MASK;
Adding buf_align to that rounded-down "pos" value will stay within
the same page; the result will just be offset by the page offset for
the "data" pointer. The final mask therefore leaves just the value
of "buf_align".
One more simplification. Note that the result of calc_pages_for()
is invariant of which page the offset starts in--the only thing that
matters is the offset within the starting page. We will have
put the proper page offset to use into "page_align", so just use
that in calculating num_pages.
This resolves:
http://tracker.ceph.com/issues/4166
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
There's a spot that computes the number of pages to allocate for a
page-aligned length by just shifting it. Use calc_pages_for()
instead, to be consistent with usage everywhere else. The result
is the same.
The reason for this is to make it clearer in an upcoming patch that
this calculation is duplicated.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Currently, incoming mds messages never use page data, which means
there is no need to set the page_alignment field in the message.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Greg Farnum <greg@inktank.com>
The only user of the ceph messenger that doesn't define an alloc_msg
method is the mds client. Define one, such that it works just like
it did before, and simplify ceph_con_in_msg_alloc() by assuming the
alloc_msg method is always present.
This and the next patch resolve:
http://tracker.ceph.com/issues/4322
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Greg Farnum <greg@inktank.com>
The purpose of ceph_calc_object_layout() is to fill in the pool
number and seed for a ceph_pg structure provided, based on a given
osd map and target object id.
Currently that function takes a file layout parameter, but the only
thing used out of that is its pool number.
Change the function so it takes a pool number rather than the full
file layout structure. Only update the ceph_pg if the pool is found
in the osd map. Get rid of few useless lines of code from the
function while there.
Since the function now very clearly just fills in the ceph_pg
structure it's provided, rename it ceph_calc_ceph_pg().
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
The pagelist_count field is never actually used, so get rid of it.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
make __ceph_do_pending_vmtruncate() acquire the i_mutex if the caller
does not hold the i_mutex, so ceph_aio_read() can call safely.
Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Greg Farnum <greg@inktank.com>
ceph_aio_write() has an optimization that marks CEPH_CAP_FILE_WR
cap dirty before data is copied to page cache and inode size is
updated. The optimization avoids slow cap revocation caused by
balance_dirty_pages(), but introduces inode size update race. If
ceph_check_caps() flushes the dirty cap before the inode size is
updated, MDS can miss the new inode size. So just remove the
optimization.
Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Greg Farnum <greg@inktank.com>
commit 22cddde104 breaks the atomicity of write operation, it also
introduces a deadlock between write and truncate.
Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Greg Farnum <greg@inktank.com>
Conflicts:
fs/ceph/addr.c
commit c6ffe10015 moved the flag that tracks if the dcache contents
for a directory are complete to dentry. The problem is there are
lots of places that use ceph_dir_{set,clear,test}_complete() while
holding i_ceph_lock. but ceph_dir_{set,clear,test}_complete() may
sleep because they call dput().
This patch basically reverts that commit. For ceph_d_prune(), it's
called with both the dentry to prune and the parent dentry are
locked. So it's safe to access the parent dentry's d_inode and
clear I_COMPLETE flag.
Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Greg Farnum <greg@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
MDS ignores cap update message if migrate_seq mismatch, so when
receiving a cap import message with higher migrate_seq, set mds_want
according to the cap import message.
Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Greg Farnum <greg@inktank.com>
Use distinct fields for tracking the number of pages in a message's
page array and in a message's page list. Currently only one or the
other is used at a time, but that will be changing soon.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Modify the request_module to prefix the file system type with "fs-"
and add aliases to all of the filesystems that can be built as modules
to match.
A common practice is to build all of the kernel code and leave code
that is not commonly needed as modules, with the result that many
users are exposed to any bug anywhere in the kernel.
Looking for filesystems with a fs- prefix limits the pool of possible
modules that can be loaded by mount to just filesystems trivially
making things safer with no real cost.
Using aliases means user space can control the policy of which
filesystem modules are auto-loaded by editing /etc/modprobe.d/*.conf
with blacklist and alias directives. Allowing simple, safe,
well understood work-arounds to known problematic software.
This also addresses a rare but unfortunate problem where the filesystem
name is not the same as it's module name and module auto-loading
would not work. While writing this patch I saw a handful of such
cases. The most significant being autofs that lives in the module
autofs4.
This is relevant to user namespaces because we can reach the request
module in get_fs_type() without having any special permissions, and
people get uncomfortable when a user specified string (in this case
the filesystem type) goes all of the way to request_module.
After having looked at this issue I don't think there is any
particular reason to perform any filtering or permission checks beyond
making it clear in the module request that we want a filesystem
module. The common pattern in the kernel is to call request_module()
without regards to the users permissions. In general all a filesystem
module does once loaded is call register_filesystem() and go to sleep.
Which means there is not much attack surface exposed by loading a
filesytem module unless the filesystem is mounted. In a user
namespace filesystems are not mounted unless .fs_flags = FS_USERNS_MOUNT,
which most filesystems do not set today.
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Acked-by: Kees Cook <keescook@chromium.org>
Reported-by: Kees Cook <keescook@google.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Pull Ceph updates from Sage Weil:
"A few groups of patches here. Alex has been hard at work improving
the RBD code, layout groundwork for understanding the new formats and
doing layering. Most of the infrastructure is now in place for the
final bits that will come with the next window.
There are a few changes to the data layout. Jim Schutt's patch fixes
some non-ideal CRUSH behavior, and a set of patches from me updates
the client to speak a newer version of the protocol and implement an
improved hashing strategy across storage nodes (when the server side
supports it too).
A pair of patches from Sam Lang fix the atomicity of open+create
operations. Several patches from Yan, Zheng fix various mds/client
issues that turned up during multi-mds torture tests.
A final set of patches expose file layouts via virtual xattrs, and
allow the policies to be set on directories via xattrs as well
(avoiding the awkward ioctl interface and providing a consistent
interface for both kernel mount and ceph-fuse users)."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client: (143 commits)
libceph: add support for HASHPSPOOL pool flag
libceph: update osd request/reply encoding
libceph: calculate placement based on the internal data types
ceph: update support for PGID64, PGPOOL3, OSDENC protocol features
ceph: update "ceph_features.h"
libceph: decode into cpu-native ceph_pg type
libceph: rename ceph_pg -> ceph_pg_v1
rbd: pass length, not op for osd completions
rbd: move rbd_osd_trivial_callback()
libceph: use a do..while loop in con_work()
libceph: use a flag to indicate a fault has occurred
libceph: separate non-locked fault handling
libceph: encapsulate connection backoff
libceph: eliminate sparse warnings
ceph: eliminate sparse warnings in fs code
rbd: eliminate sparse warnings
libceph: define connection flag helpers
rbd: normalize dout() calls
rbd: barriers are hard
rbd: ignore zero-length requests
...
