Pull vfs updates from Al Viro:
"The first vfs pile, with deep apologies for being very late in this
window.
Assorted cleanups and fixes, plus a large preparatory part of iov_iter
work. There's a lot more of that, but it'll probably go into the next
merge window - it *does* shape up nicely, removes a lot of
boilerplate, gets rid of locking inconsistencie between aio_write and
splice_write and I hope to get Kent's direct-io rewrite merged into
the same queue, but some of the stuff after this point is having
(mostly trivial) conflicts with the things already merged into
mainline and with some I want more testing.
This one passes LTP and xfstests without regressions, in addition to
usual beating. BTW, readahead02 in ltp syscalls testsuite has started
giving failures since "mm/readahead.c: fix readahead failure for
memoryless NUMA nodes and limit readahead pages" - might be a false
positive, might be a real regression..."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (63 commits)
missing bits of "splice: fix racy pipe->buffers uses"
cifs: fix the race in cifs_writev()
ceph_sync_{,direct_}write: fix an oops on ceph_osdc_new_request() failure
kill generic_file_buffered_write()
ocfs2_file_aio_write(): switch to generic_perform_write()
ceph_aio_write(): switch to generic_perform_write()
xfs_file_buffered_aio_write(): switch to generic_perform_write()
export generic_perform_write(), start getting rid of generic_file_buffer_write()
generic_file_direct_write(): get rid of ppos argument
btrfs_file_aio_write(): get rid of ppos
kill the 5th argument of generic_file_buffered_write()
kill the 4th argument of __generic_file_aio_write()
lustre: don't open-code kernel_recvmsg()
ocfs2: don't open-code kernel_recvmsg()
drbd: don't open-code kernel_recvmsg()
constify blk_rq_map_user_iov() and friends
lustre: switch to kernel_sendmsg()
ocfs2: don't open-code kernel_sendmsg()
take iov_iter stuff to mm/iov_iter.c
process_vm_access: tidy up a bit
...
Pull renameat2 system call from Miklos Szeredi:
"This adds a new syscall, renameat2(), which is the same as renameat()
but with a flags argument.
The purpose of extending rename is to add cross-rename, a symmetric
variant of rename, which exchanges the two files. This allows
interesting things, which were not possible before, for example
atomically replacing a directory tree with a symlink, etc... This
also allows overlayfs and friends to operate on whiteouts atomically.
Andy Lutomirski also suggested a "noreplace" flag, which disables the
overwriting behavior of rename.
These two flags, RENAME_EXCHANGE and RENAME_NOREPLACE are only
implemented for ext4 as an example and for testing"
* 'cross-rename' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
ext4: add cross rename support
ext4: rename: split out helper functions
ext4: rename: move EMLINK check up
ext4: rename: create ext4_renament structure for local vars
vfs: add cross-rename
vfs: lock_two_nondirectories: allow directory args
security: add flags to rename hooks
vfs: add RENAME_NOREPLACE flag
vfs: add renameat2 syscall
vfs: rename: use common code for dir and non-dir
vfs: rename: move d_move() up
vfs: add d_is_dir()
Add flags to security_path_rename() and security_inode_rename() hooks.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reviewed-by: J. Bruce Fields <bfields@redhat.com>
Add new renameat2 syscall, which is the same as renameat with an added
flags argument.
Pass flags to vfs_rename() and to i_op->rename() as well.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reviewed-by: J. Bruce Fields <bfields@redhat.com>
Pull vfs updates from Al Viro:
"All kinds of stuff this time around; some more notable parts:
- RCU'd vfsmounts handling
- new primitives for coredump handling
- files_lock is gone
- Bruce's delegations handling series
- exportfs fixes
plus misc stuff all over the place"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (101 commits)
ecryptfs: ->f_op is never NULL
locks: break delegations on any attribute modification
locks: break delegations on link
locks: break delegations on rename
locks: helper functions for delegation breaking
locks: break delegations on unlink
namei: minor vfs_unlink cleanup
locks: implement delegations
locks: introduce new FL_DELEG lock flag
vfs: take i_mutex on renamed file
vfs: rename I_MUTEX_QUOTA now that it's not used for quotas
vfs: don't use PARENT/CHILD lock classes for non-directories
vfs: pull ext4's double-i_mutex-locking into common code
exportfs: fix quadratic behavior in filehandle lookup
exportfs: better variable name
exportfs: move most of reconnect_path to helper function
exportfs: eliminate unused "noprogress" counter
exportfs: stop retrying once we race with rename/remove
exportfs: clear DISCONNECTED on all parents sooner
exportfs: more detailed comment for path_reconnect
...
We need to break delegations on any operation that changes the set of
links pointing to an inode. Start with unlink.
Such operations also hold the i_mutex on a parent directory. Breaking a
delegation may require waiting for a timeout (by default 90 seconds) in
the case of a unresponsive NFS client. To avoid blocking all directory
operations, we therefore drop locks before waiting for the delegation.
The logic then looks like:
acquire locks
...
test for delegation; if found:
take reference on inode
release locks
wait for delegation break
drop reference on inode
retry
It is possible this could never terminate. (Even if we take precautions
to prevent another delegation being acquired on the same inode, we could
get a different inode on each retry.) But this seems very unlikely.
The initial test for a delegation happens after the lock on the target
inode is acquired, but the directory inode may have been acquired
further up the call stack. We therefore add a "struct inode **"
argument to any intervening functions, which we use to pass the inode
back up to the caller in the case it needs a delegation synchronously
broken.
Cc: David Howells <dhowells@redhat.com>
Cc: Tyler Hicks <tyhicks@canonical.com>
Cc: Dustin Kirkland <dustin.kirkland@gazzang.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Provide the ability to enable and disable fscache cookies. A disabled cookie
will reject or ignore further requests to:
Acquire a child cookie
Invalidate and update backing objects
Check the consistency of a backing object
Allocate storage for backing page
Read backing pages
Write to backing pages
but still allows:
Checks/waits on the completion of already in-progress objects
Uncaching of pages
Relinquishment of cookies
Two new operations are provided:
(1) Disable a cookie:
void fscache_disable_cookie(struct fscache_cookie *cookie,
bool invalidate);
If the cookie is not already disabled, this locks the cookie against other
dis/enablement ops, marks the cookie as being disabled, discards or
invalidates any backing objects and waits for cessation of activity on any
associated object.
This is a wrapper around a chunk split out of fscache_relinquish_cookie(),
but it reinitialises the cookie such that it can be reenabled.
All possible failures are handled internally. The caller should consider
calling fscache_uncache_all_inode_pages() afterwards to make sure all page
markings are cleared up.
(2) Enable a cookie:
void fscache_enable_cookie(struct fscache_cookie *cookie,
bool (*can_enable)(void *data),
void *data)
If the cookie is not already enabled, this locks the cookie against other
dis/enablement ops, invokes can_enable() and, if the cookie is not an
index cookie, will begin the procedure of acquiring backing objects.
The optional can_enable() function is passed the data argument and returns
a ruling as to whether or not enablement should actually be permitted to
begin.
All possible failures are handled internally. The cookie will only be
marked as enabled if provisional backing objects are allocated.
A later patch will introduce these to NFS. Cookie enablement during nfs_open()
is then contingent on i_writecount <= 0. can_enable() checks for a race
between open(O_RDONLY) and open(O_WRONLY/O_RDWR). This simplifies NFS's cookie
handling and allows us to get rid of open(O_RDONLY) accidentally introducing
caching to an inode that's open for writing already.
One operation has its API modified:
(3) Acquire a cookie.
struct fscache_cookie *fscache_acquire_cookie(
struct fscache_cookie *parent,
const struct fscache_cookie_def *def,
void *netfs_data,
bool enable);
This now has an additional argument that indicates whether the requested
cookie should be enabled by default. It doesn't need the can_enable()
function because the caller must prevent multiple calls for the same netfs
object and it doesn't need to take the enablement lock because no one else
can get at the cookie before this returns.
Signed-off-by: David Howells <dhowells@redhat.com
Don't try to dump the index key that distinguishes an object if netfs
data in the cookie the object refers to has been cleared (ie. the
cookie has passed most of the way through
__fscache_relinquish_cookie()).
Since the netfs holds the index key, we can't get at it once the ->def
and ->netfs_data pointers have been cleared - and a NULL pointer
exception will ensue, usually just after a:
CacheFiles: Error: Unexpected object collision
error is reported.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In cachefiles_check_auxdata(), we allocate auxbuf but fail to free it if
we determine there's an error or that the data is stale.
Further, assigning the output of vfs_getxattr() to auxbuf->len gives
problems with checking for errors as auxbuf->len is a u16. We don't
actually need to set auxbuf->len, so keep the length in a variable for
now. We shouldn't need to check the upper limit of the buffer as an
overflow there should be indicated by -ERANGE.
While we're at it, fscache_check_aux() returns an enum value, not an
int, so assign it to an appropriately typed variable rather than to ret.
Signed-off-by: Josh Boyer <jwboyer@fedoraproject.org>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Hongyi Jia <jiayisuse@gmail.com>
cc: Milosz Tanski <milosz@adfin.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now that the LRU to add a page to is decided at LRU-add time, remove the
misleading lru parameter from __pagevec_lru_add. A consequence of this
is that the pagevec_lru_add_file, pagevec_lru_add_anon and similar
helpers are misleading as the caller no longer has direct control over
what LRU the page is added to. Unused helpers are removed by this patch
and existing users of pagevec_lru_add_file() are converted to use
lru_cache_add_file() directly and use the per-cpu pagevecs instead of
creating their own pagevec.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Alexey Lyahkov <alexey.lyashkov@gmail.com>
Cc: Andrew Perepechko <anserper@ya.ru>
Cc: Robin Dong <sanbai@taobao.com>
Cc: Theodore Tso <tytso@mit.edu>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Bernd Schubert <bernd.schubert@fastmail.fm>
Cc: David Howells <dhowells@redhat.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Simplify the way fscache cache objects retain their cookie. The way I
implemented the cookie storage handling made synchronisation a pain (ie. the
object state machine can't rely on the cookie actually still being there).
Instead of the the object being detached from the cookie and the cookie being
freed in __fscache_relinquish_cookie(), we defer both operations:
(*) The detachment of the object from the list in the cookie now takes place
in fscache_drop_object() and is thus governed by the object state machine
(fscache_detach_from_cookie() has been removed).
(*) The release of the cookie is now in fscache_object_destroy() - which is
called by the cache backend just before it frees the object.
This means that the fscache_cookie struct is now available to the cache all the
way through from ->alloc_object() to ->drop_object() and ->put_object() -
meaning that it's no longer necessary to take object->lock to guarantee access.
However, __fscache_relinquish_cookie() doesn't wait for the object to go all
the way through to destruction before letting the netfs proceed. That would
massively slow down the netfs. Since __fscache_relinquish_cookie() leaves the
cookie around, in must therefore break all attachments to the netfs - which
includes ->def, ->netfs_data and any outstanding page read/writes.
To handle this, struct fscache_cookie now has an n_active counter:
(1) This starts off initialised to 1.
(2) Any time the cache needs to get at the netfs data, it calls
fscache_use_cookie() to increment it - if it is not zero. If it was zero,
then access is not permitted.
(3) When the cache has finished with the data, it calls fscache_unuse_cookie()
to decrement it. This does a wake-up on it if it reaches 0.
(4) __fscache_relinquish_cookie() decrements n_active and then waits for it to
reach 0. The initialisation to 1 in step (1) ensures that we only get
wake ups when we're trying to get rid of the cookie.
This leaves __fscache_relinquish_cookie() a lot simpler.
***
This fixes a problem in the current code whereby if fscache_invalidate() is
followed sufficiently quickly by fscache_relinquish_cookie() then it is
possible for __fscache_relinquish_cookie() to have detached the cookie from the
object and cleared the pointer before a thread is dispatched to process the
invalidation state in the object state machine.
Since the pending write clearance was deferred to the invalidation state to
make it asynchronous, we need to either wait in relinquishment for the stores
tree to be cleared in the invalidation state or we need to handle the clearance
in relinquishment.
Further, if the relinquishment code does clear the tree, then the invalidation
state need to make the clearance contingent on still having the cookie to hand
(since that's where the tree is rooted) and we have to prevent the cookie from
disappearing for the duration.
This can lead to an oops like the following:
BUG: unable to handle kernel NULL pointer dereference at 000000000000000c
...
RIP: 0010:[<ffffffff8151023e>] _spin_lock+0xe/0x30
...
CR2: 000000000000000c ...
...
Process kslowd002 (...)
....
Call Trace:
[<ffffffffa01c3278>] fscache_invalidate_writes+0x38/0xd0 [fscache]
[<ffffffff810096f0>] ? __switch_to+0xd0/0x320
[<ffffffff8105e759>] ? find_busiest_queue+0x69/0x150
[<ffffffff8110ddd4>] ? slow_work_enqueue+0x104/0x180
[<ffffffffa01c1303>] fscache_object_slow_work_execute+0x5e3/0x9d0 [fscache]
[<ffffffff81096b67>] ? bit_waitqueue+0x17/0xd0
[<ffffffff8110e233>] slow_work_execute+0x233/0x310
[<ffffffff8110e515>] slow_work_thread+0x205/0x360
[<ffffffff81096ca0>] ? autoremove_wake_function+0x0/0x40
[<ffffffff8110e310>] ? slow_work_thread+0x0/0x360
[<ffffffff81096936>] kthread+0x96/0xa0
[<ffffffff8100c0ca>] child_rip+0xa/0x20
[<ffffffff810968a0>] ? kthread+0x0/0xa0
[<ffffffff8100c0c0>] ? child_rip+0x0/0x20
The parameter to fscache_invalidate_writes() was object->cookie which is NULL.
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-By: Milosz Tanski <milosz@adfin.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Fix object state machine to have separate work and wait states as that makes
it easier to envision.
There are now three kinds of state:
(1) Work state. This is an execution state. No event processing is performed
by a work state. The function attached to a work state returns a pointer
indicating the next state to which the OSM should transition. Returning
NO_TRANSIT repeats the current state, but goes back to the scheduler
first.
(2) Wait state. This is an event processing state. No execution is
performed by a wait state. Wait states are just tables of "if event X
occurs, clear it and transition to state Y". The dispatcher returns to
the scheduler if none of the events in which the wait state has an
interest are currently pending.
(3) Out-of-band state. This is a special work state. Transitions to normal
states can be overridden when an unexpected event occurs (eg. I/O error).
Instead the dispatcher disables and clears the OOB event and transits to
the specified work state. This then acts as an ordinary work state,
though object->state points to the overridden destination. Returning
NO_TRANSIT resumes the overridden transition.
In addition, the states have names in their definitions, so there's no need for
tables of state names. Further, the EV_REQUEUE event is no longer necessary as
that is automatic for work states.
Since the states are now separate structs rather than values in an enum, it's
not possible to use comparisons other than (non-)equality between them, so use
some object->flags to indicate what phase an object is in.
The EV_RELEASE, EV_RETIRE and EV_WITHDRAW events have been squished into one
(EV_KILL). An object flag now carries the information about retirement.
Similarly, the RELEASING, RECYCLING and WITHDRAWING states have been merged
into an KILL_OBJECT state and additional states have been added for handling
waiting dependent objects (JUMPSTART_DEPS and KILL_DEPENDENTS).
A state has also been added for synchronising with parent object initialisation
(WAIT_FOR_PARENT) and another for initiating look up (PARENT_READY).
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-By: Milosz Tanski <milosz@adfin.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Wrap checks on object state (mostly outside of fs/fscache/object.c) with
inline functions so that the mechanism can be replaced.
Some of the state checks within object.c are left as-is as they will be
replaced.
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-By: Milosz Tanski <milosz@adfin.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Just some cleanup.
(And note the caller of this function may, for example, call vfs_unlink
on a child, so the "1" (I_MUTEX_PARENT) really was what was intended
here.)
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-By: Milosz Tanski <milosz@adfin.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Mark as cancelled an operation that is in progress rather than pending at the
time it is cancelled, and call fscache_complete_op() to cancel an operation so
that blocked ops can be started.
Signed-off-by: David Howells <dhowells@redhat.com>
Don't mask off the object event mask when printing it. That way it can be seen
if threre are bits set that shouldn't be.
Signed-off-by: David Howells <dhowells@redhat.com>
Implement invalidation for CacheFiles. This is in two parts:
(1) Provide an invalidation method (which just truncates the backing file).
(2) Abort attempts to copy anything read from the backing file whilst
invalidation is in progress.
Question: CacheFiles uses truncation in a couple of places. It has been using
notify_change() rather than sys_truncate() or something similar. This means
it bypasses a bunch of checks and suchlike that it possibly should be making
(security, file locking, lease breaking, vfsmount write). Should it be using
vfs_truncate() as added by a preceding patch or should it use notify_write()
and assume that anyone poking around in the cache files on disk gets
everything they deserve?
Signed-off-by: David Howells <dhowells@redhat.com>
