Followup to the UFS series - with the way we clear the new blocks (via
buffer cache, possibly on more than a page worth of file) we really
should not insert a reference to new block into inode block tree until
after we'd cleared it.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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>
Currently - on lock_ufs(), eventually - on per-inode mutex.
lock_ufs() used to be mere BKL, which is much weaker, so it needed
those rechecks. BKL doesn't provide any exclusion once we lose CPU;
its blind replacement, OTOH, _does_. Making that per-filesystem was
an atrocity, but at least we can simplify life here. And yes, we
certainly need to make that sucker per-inode - these days inode.c and
truncate.c uses are needed only to protect the block pointers.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
There were 3 remaining users; in two of them we took ->s_lock immediately
after lock_ufs() and held it until just before unlock_ufs(); the third
one (statfs) could not be called from itself or from other two (remount
and sync_fs). Just use ->s_lock in statfs and don't bother with lock_ufs
at all.
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>
right now it doesn't matter (lock_ufs() serializes everything),
but when we switch to per-inode locking, it will be needed.
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>
Pull more vfs updates from Al Viro:
"Assorted VFS fixes and related cleanups (IMO the most interesting in
that part are f_path-related things and Eric's descriptor-related
stuff). UFS regression fixes (it got broken last cycle). 9P fixes.
fs-cache series, DAX patches, Jan's file_remove_suid() work"
[ I'd say this is much more than "fixes and related cleanups". The
file_table locking rule change by Eric Dumazet is a rather big and
fundamental update even if the patch isn't huge. - Linus ]
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (49 commits)
9p: cope with bogus responses from server in p9_client_{read,write}
p9_client_write(): avoid double p9_free_req()
9p: forgetting to cancel request on interrupted zero-copy RPC
dax: bdev_direct_access() may sleep
block: Add support for DAX reads/writes to block devices
dax: Use copy_from_iter_nocache
dax: Add block size note to documentation
fs/file.c: __fget() and dup2() atomicity rules
fs/file.c: don't acquire files->file_lock in fd_install()
fs:super:get_anon_bdev: fix race condition could cause dev exceed its upper limitation
vfs: avoid creation of inode number 0 in get_next_ino
namei: make set_root_rcu() return void
make simple_positive() public
ufs: use dir_pages instead of ufs_dir_pages()
pagemap.h: move dir_pages() over there
remove the pointless include of lglock.h
fs: cleanup slight list_entry abuse
xfs: Correctly lock inode when removing suid and file capabilities
fs: Call security_ops->inode_killpriv on truncate
fs: Provide function telling whether file_remove_privs() will do anything
...
Pull cgroup writeback support from Jens Axboe:
"This is the big pull request for adding cgroup writeback support.
This code has been in development for a long time, and it has been
simmering in for-next for a good chunk of this cycle too. This is one
of those problems that has been talked about for at least half a
decade, finally there's a solution and code to go with it.
Also see last weeks writeup on LWN:
http://lwn.net/Articles/648292/"
* 'for-4.2/writeback' of git://git.kernel.dk/linux-block: (85 commits)
writeback, blkio: add documentation for cgroup writeback support
vfs, writeback: replace FS_CGROUP_WRITEBACK with SB_I_CGROUPWB
writeback: do foreign inode detection iff cgroup writeback is enabled
v9fs: fix error handling in v9fs_session_init()
bdi: fix wrong error return value in cgwb_create()
buffer: remove unusued 'ret' variable
writeback: disassociate inodes from dying bdi_writebacks
writeback: implement foreign cgroup inode bdi_writeback switching
writeback: add lockdep annotation to inode_to_wb()
writeback: use unlocked_inode_to_wb transaction in inode_congested()
writeback: implement unlocked_inode_to_wb transaction and use it for stat updates
writeback: implement [locked_]inode_to_wb_and_lock_list()
writeback: implement foreign cgroup inode detection
writeback: make writeback_control track the inode being written back
writeback: relocate wb[_try]_get(), wb_put(), inode_{attach|detach}_wb()
mm: vmscan: disable memcg direct reclaim stalling if cgroup writeback support is in use
writeback: implement memcg writeback domain based throttling
writeback: reset wb_domain->dirty_limit[_tstmp] when memcg domain size changes
writeback: implement memcg wb_domain
writeback: update wb_over_bg_thresh() to use wb_domain aware operations
...
Al Viro
Linus Torvalds