kmap() in page_follow_link_light() needed to go - allowing to hold
an arbitrary number of kmaps for long is a great way to deadlocking
the system.
new helper (inode_nohighmem(inode)) needs to be used for pagecache
symlinks inodes; done for all in-tree cases. page_follow_link_light()
instrumented to yell about anything missed.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
It was to needed for a couple of months in 2010, until UFS
quota support got dropped. Since then it's equivalent to
simple_setattr() (i.e. the default) for everything except the
regular files. And dropping it there allows to convert all
UFS symlinks to {page,simple}_symlink_inode_operations, getting
rid of fs/ufs/symlink.c completely.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Just pass NULL as locked_page in case of first block in the indirect
chain. Old calling conventions aside, a reason for having 'phys'
was that ufs_inode_getfrag() used to be able to do _two_ allocations
- indirect block and extending/reallocating a tail. We needed
locked_page for the latter (it's a data), but we also needed to
figure out that indirect block is metadata. So we used to pass
non-NULL locked_page in all cases *and* used NULL phys as
indication of being asked to allocate an indirect.
With tail unpacking taken into a separate function we don't need
those convolutions anymore.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The value passed to ufs_inode_getblock() as the 3rd argument
had lower bits ignored; the upper bits were shifted down
and used and they actually make sense - those are _lower_ bits
of index in indirect block (i.e. they form the index within
a fragment within an indirect block).
Pass those as argument. Upper bits of index (i.e. the number
of fragment within indirect block) will join them shortly.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
These calling conventions are rudiments of pre-2.3 times; they
really need to be sanitized. This is the first step; next
will be _always_ returning a block number, instead of this
"return a pointer to buffer_head, except when we get to the
actual data" crap.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
... and massage ufs_frag_map() to take those instead of fragment number.
As it is, we duplicate the damn thing on the write side, open-coded and
bloody hard to follow.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
We are holding ->truncate_mutex, so nobody else can alter our
block pointers. Rechecks/retries were needed back when we
only held BKL there, and had to cope with write_begin/writepage
and writepage/truncate races. Can't happen anymore...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
There's a case when an indirect block gets dirtied for no good
reason - when there's a hole starting in the middle of area
covered by it and spanning past its end, and truncate() is done
precisely to the beginning of the hole.
The block is obviously not modified at all - all removals happen
beyond it. However, existing code ends up dirtying it just in
case. It's trivial to fix and while it's not a real bug by any
stretch of imagination, it makes the damn thing harder to follow.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Note that it's already made unreachable from the inode, so we don't have
to worry about ufs_frag_map() walking into something already freed.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Have caller fetch the block number *and* remove it from wherever
it was. Pass the block number instead.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
We always have 0 < depth2 <= depth in there, so
if (--depth) {
if (--depth2)
A
B
} else {
C // not using depth2
}
D // not using depth2
is equivalent to
if (--depth2)
A with s/depth/depth - 1/
if (--depth)
B
else
C
D
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
For calls in __ufs_truncate_blocks() it's just a matter of not
incrementing offsets[0] and not making that call - immediately
following loop will be executed one extra time and we'll be just
fine. For recursive call in ufs_trunc_branch() itself, just
assing NULL to offsets if we would be about to make such call.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Instead of manually checking that the array contains only zeroes,
find the position of the last non-zero (in __ufs_truncate(), where
we can conveniently do that) and use that to tell if there's
any non-zero in the array tail passed to ufs_trunc_...indirect().
The goal of all that clumsiness is to get fold these functions
together.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
rather than bitslicing the offset just formed as sum of shifted indices,
pass the array of those indices itself. NULL is used as equivalent
of "all zeroes" (== free the entire branch).
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
IOW, the distance of cutoff from the begining of the branch
(in blocks).
That (and the fact that block just prior to cutoff is guaranteed to
be present) allows to tell whether to free triple indirect block
just by looking at the offset.
While we are at it, using u64 for index in the block is wrong -
those should be unsigned int.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Use ufs_block_to_path() to find the cutoff path in the block pointers' tree.
For now just use the information about the depth (to bypass the fully
preserved subtrees); subsequent commits will use the information about actual
path.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
type makes no sense - those are indices in block number arrays, not
block numbers. And no, UFS is not likely to grow indirect blocks with
4Gpointers in them...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
It is closely tied to block pointers handling there, can benefit
from existing helpers, etc. - no point keeping them apart.
Trimmed the trailing whitespaces in inode.c at the same time.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* stores to block pointers are under per-inode seqlock (meta_lock) and
mutex (truncate_mutex)
* fetches of block pointers are either under truncate_mutex, or wrapped
into seqretry loop on meta_lock
* all changes of ->i_size are under truncate_mutex and i_mutex
* all changes of ->i_lastfrag are under truncate_mutex
It's similar to what ext2 is doing; the main difference is that unlike
ext2 we can't rely upon the atomicity of stores into block pointers -
on UFS2 they are 64bit. So we can't cut the corner when switching
a pointer from NULL to non-NULL as we could in ext2_splice_branch()
and need to use meta_lock on all modifications.
We use seqlock where ext2 uses rwlock; ext2 could probably also benefit
from such change...
Another non-trivial difference is that with UFS we *cannot* have reader
grab truncate_mutex in case of race - it has to keep retrying. That
might be possible to change, but not until we lift tail unpacking
several levels up in call chain.
After that commit we do *NOT* hold fs-wide serialization on accesses
to block pointers anymore. Moreover, lock_ufs() can become a normal
mutex now - it's only used on statfs, remount and sync_fs and none
of those uses are recursive. As the matter of fact, *now* it can be
collapsed with ->s_lock, and be eventually replaced with saner
per-cylinder-group spinlocks, but that's a separate story.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Broken in "[PATCH] ufs: truncate should allocate block for last byte";
all way back in 2006. ufs_setattr() hadn't been the only user of
vmtruncate() and eliminating ->truncate() method required corrections
in a bunch of places. Eventually those places had migrated into
->write_begin() failure exit and ->write_end() after short copy...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
a) move it inside ufs_truncate()
b) ufs_free_inode() doesn't need it - it's serialized on ->s_lock
c) ufs_write_inode() doesn't need it either (and can be called without
it anyway).
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This reverts commit 9ef7db7f38 ("ufs: fix deadlocks introduced by sb
mutex merge") That patch tried to solve commit 0244756edc ("ufs: sb
mutex merge + mutex_destroy") which is itself partially reverted due to
multiple deadlocks.
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Suggested-by: Jan Kara <jack@suse.cz>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Evgeniy Dushistov <dushistov@mail.ru>
Cc: Alexey Khoroshilov <khoroshilov@ispras.ru>
Cc: Roger Pau Monne <roger.pau@citrix.com>
Cc: Ian Jackson <Ian.Jackson@eu.citrix.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Commit 0244756edc ("ufs: sb mutex merge + mutex_destroy") introduces
deadlocks in ufs_new_inode() and ufs_free_inode().
Most callers of that functions acqure the mutex by themselves and
ufs_{new,free}_inode() do that via lock_ufs(),
i.e we have an unavoidable double lock.
The patch proposes to resolve the issue by making sure that
ufs_{new,free}_inode() are not called with the mutex held.
Found by Linux Driver Verification project (linuxtesting.org).
Cc: stable@vger.kernel.org # 3.16
Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Reclaim will be leaving shadow entries in the page cache radix tree upon
evicting the real page. As those pages are found from the LRU, an
iput() can lead to the inode being freed concurrently. At this point,
reclaim must no longer install shadow pages because the inode freeing
code needs to ensure the page tree is really empty.
Add an address_space flag, AS_EXITING, that the inode freeing code sets
under the tree lock before doing the final truncate. Reclaim will check
for this flag before installing shadow pages.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Minchan Kim <minchan@kernel.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Bob Liu <bob.liu@oracle.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Luigi Semenzato <semenzato@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Metin Doslu <metin@citusdata.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Ozgun Erdogan <ozgun@citusdata.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roman Gushchin <klamm@yandex-team.ru>
Cc: Ryan Mallon <rmallon@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
truncate_pagecache() doesn't care about old size since commit
cedabed49b ("vfs: Fix vmtruncate() regression"). Let's drop it.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: 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>
Al Viro