Bits, which are related to Bitmap Descriptor logical blocks,
are not reset when buffer headers are allocated for them. As the
result, these logical blocks can be treated as free and
be used for other blocks.This can cause usage of one buffer header
for several types of data. UDF issues WARNING in this situation:

WARNING: CPU: 0 PID: 2703 at fs/udf/inode.c:2014
  __udf_add_aext+0x685/0x7d0 fs/udf/inode.c:2014

RIP: 0010:__udf_add_aext+0x685/0x7d0 fs/udf/inode.c:2014
Call Trace:
 udf_setup_indirect_aext+0x573/0x880 fs/udf/inode.c:1980
 udf_add_aext+0x208/0x2e0 fs/udf/inode.c:2067
 udf_insert_aext fs/udf/inode.c:2233 [inline]
 udf_update_extents fs/udf/inode.c:1181 [inline]
 inode_getblk+0x1981/0x3b70 fs/udf/inode.c:885

Found by Linux Verification Center (linuxtesting.org) with syzkaller.

[JK: Somewhat cleaned up the boundary checks]

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Signed-off-by: Vladislav Efanov <VEfanov@ispras.ru>
Signed-off-by: Jan Kara <jack@suse.cz>

numFiles entry in LVID should actually contain number for non-dir file
entries, not the number of non-dir inodes. Move the counting from inode
allocation / deallocation into directory entry handling functions.
Signed-off-by: Jan Kara <jack@suse.cz>

UDF disk format supports in principle file sizes up to 1<<64-1. However
the file space (including holes) is described by a linked list of
extents, each of which can have at most 1GB. Thus the creation and
handling of extents gets unusably slow beyond certain point. Limit the
file size to 4TB to avoid locking up the kernel too easily.
Signed-off-by: Jan Kara <jack@suse.cz>

Nobody uses the bh returned from udf_expand_dir_adinicb(). Don't return
it.
Signed-off-by: Jan Kara <jack@suse.cz>

Remove the last two remaining kmap_atomic() uses in UDF in
udf_expand_file_adinicb(). The first use can be actually conveniently
replaced with udf_adinicb_readpage(), the second with memcpy_to_page().
Signed-off-by: Jan Kara <jack@suse.cz>

Instead of mapping the page manually with kmap() atomic, use helper
memcpy_to_page(). Also delete the pointless SetPageUptodate() call.
Signed-off-by: Jan Kara <jack@suse.cz>

Instead of using kmap_atomic() use kmap_local_page() in
udf_adinicb_readpage().
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

udf_adinicb_readpage() is only called from aops functions, move it to
the same file as its callers and also drop the stale comment -
invalidate_lock is protecting us against races with truncate.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

Mark functions implementing aops static since they are not needed
outside of inode.c anymore.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

Now that udf_aops and udf_adiniicb_aops are functionally identical, just
drop udf_adiniicb_aops.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

Add detection of in-ICB files to udf_bmap() and return error in that
case. This will allow us o use single address_space_operations in UDF.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

Switching address_space_operations while a file is used is difficult to
do in a race-free way. To be able to use single address_space_operations
in UDF, create udf_write_end() function that is able to handle both
normal and in-ICB files.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

Switching address_space_operations while a file is used is difficult to
do in a race-free way. To be able to use single address_space_operations
in UDF, make in-ICB files use udf_write_begin().
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

Switching address_space_operations while a file is used is difficult to
do in a race-free way. To be able to use single address_space_operations
in UDF, make in-ICB files use udf_direct_IO().
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

Switching address_space_operations while a file is used is difficult to
do in a race-free way. To be able to use single address_space_operations
in UDF, make in-ICB files use udf_writepages().

Reported-by: syzbot+c27475eb921c46bbdc62@syzkaller.appspotmail.com
Reported-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

Switching address_space_operations while a file is used is difficult to
do in a race-free way. To be able to use single address_space_operations
in UDF, make udf_read_folio() handle both normal and in-ICB files.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

The condition determining whether the preallocation can be used had
an off-by-one error so we didn't discard preallocation when new
allocation was just following it. This can then confuse code in
inode_getblk().

CC: stable@vger.kernel.org
Fixes: 16d05565 ("udf: Discard preallocation before extending file with a hole")
Signed-off-by: Jan Kara <jack@suse.cz>

When we append new block just after the end of preallocated extent, the
code in inode_getblk() wrongly determined we're going to use the
preallocated extent which resulted in adding block into a wrong logical
offset in the file. Sequence like this manifests it:

xfs_io -f -c "pwrite 0x2cacf 0xd122" -c "truncate 0x2dd6f" \
  -c "pwrite 0x27fd9 0x69a9" -c "pwrite 0x32981 0x7244" <file>

The code that determined the use of preallocated extent is actually
stale because udf_do_extend_file() does not create preallocation anymore
so after calling that function we are sure there's no usable
preallocation. Just remove the faulty condition.

CC: stable@vger.kernel.org
Fixes: 16d05565 ("udf: Discard preallocation before extending file with a hole")
Signed-off-by: Jan Kara <jack@suse.cz>

Now when we allocate blocks on write page fault there should be no block
allocation happening on page writeback. So just ignore the 'create' flag
passed to udf_get_block(). Note that we can spot dirty buffers without
underlying blocks allocated in writeback when we race with expanding
truncate. However in that case these buffers do not contain valid data
so we can safely ignore them and we would just create ourselves problem
when to trim the tail extent.
Signed-off-by: Jan Kara <jack@suse.cz>

When filesystem's ->get_block function does not map the buffer head when
called from __mpage_writepage(), the function will happily go and pass
bogus bdev and block number to bio allocation routines which leads to
crashes sooner or later. E.g. UDF can do this because it doesn't want to
allocate blocks from ->writepages callbacks. It allocates blocks on
write or page fault but writeback can still spot dirty buffers without
underlying blocks allocated e.g. if blocksize < pagesize, the tail page
is dirtied (which means all its buffers are dirtied), and truncate
extends the file so that some buffer starts to be within i_size.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

Currently if file with holes is mapped, udf allocates blocks for dirtied
pages during page writeback. This however creates problems when to
truncate final extent to proper size and currently we leave the last
extent untruncated which violates UDF standard. So allocate blocks on
write page fault instead. In that case the last extent gets truncated
the file is closed and everything is happy.
Signed-off-by: Jan Kara <jack@suse.cz>

Protect truncate and file type conversion in udf_file_write_iter() with
invalidate lock. That will allow us to serialize these paths with page
faults so that the page fault can determine the file type in a racefree
way.
Signed-off-by: Jan Kara <jack@suse.cz>

When udf_expand_file_adinicb() fails, we can now use the standard exit
path instead of implementing our own.
Signed-off-by: Jan Kara <jack@suse.cz>

Push i_data_sem locking into udf_extend_file(). It somewhat simplifies
the code around it.
Signed-off-by: Jan Kara <jack@suse.cz>

The checks we do in udf_setsize() and udf_file_write_iter() are safe to
do only with i_rwsem locked as it stabilizes both file type and file
size. Hence we don't need to lock i_data_sem before we enter
udf_expand_file_adinicb() which simplifies the locking somewhat.
Signed-off-by: Jan Kara <jack@suse.cz>

When we are renaming a directory to a different directory, we need to
update '..' entry in the moved directory. However nothing prevents moved
directory from being modified and even converted from the in-ICB format
to the normal format which results in a crash. Fix the problem by
locking the moved directory.

Reported-by: syzbot+aebf90eea2671c43112a@syzkaller.appspotmail.com
Signed-off-by: Jan Kara <jack@suse.cz>

udf_getblk() has a single call site. Fold it there.
Signed-off-by: Jan Kara <jack@suse.cz>

Use the new function udf_map_block() in udf_getblk().
Signed-off-by: Jan Kara <jack@suse.cz>

In some cases we don't want to create block preallocation when
allocating blocks. Add a flag to udf_map_rq controlling the behavior.
Signed-off-by: Jan Kara <jack@suse.cz>

Pass struct udf_map_rq into inode_getblk() instead of unfolding it and
the putting the results back.
Signed-off-by: Jan Kara <jack@suse.cz>

udf_block_map() has now only a single caller. Fold it there.
Signed-off-by: Jan Kara <jack@suse.cz>

Convert udf_symlink_filler() to use udf_bread() instead of mapping and
reading buffer head manually.
Signed-off-by: Jan Kara <jack@suse.cz>

Currently udf_symlink_filler() called udf_block_map() even on files
which have data stored inside the ICB. This is invalid as we cannot map
blocks for such files (although so far the error got silently ignored).
The call happened because we could not call block mapping function once
we've acquired i_data_sem and determined whether the file has data
stored in the ICB. For symlinks the situation is luckily simple as they
get never modified so file type never changes once it is set. Hence we
can check the file type even without i_data_sem. Just drop the
i_data_sem locking and move block mapping to where it is needed.
Signed-off-by: Jan Kara <jack@suse.cz>

Use udf_bread() instead of mapping and loadign buffer head manually in
udf_load_vat().
Signed-off-by: Jan Kara <jack@suse.cz>

Use udf_bread() instead of mapping and reading buffer head manually in
udf_get_pblock_virt15().
Signed-off-by: Jan Kara <jack@suse.cz>

Create new block mapping function udf_map_block() that takes new
udf_map_rq structure describing mapping request. We will convert other
places to use this function for block mapping.
Signed-off-by: Jan Kara <jack@suse.cz>

inode_getblk() sets goal block for the next allocation to the currently
allocated block. This is obviously one less than what the goal block
should be which we fixup in udf_get_block(). Just set the right goal
block directly in inode_getblk().
Signed-off-by: Jan Kara <jack@suse.cz>

UDF was supporting a strange mode where the media was containing 7
blocks of unknown data for every 32 blocks of the filesystem. I have yet
to see the media that would need such conversion (maybe it comes from
packet writing times) and the conversions have been inconsistent in the
code. In particular any write will write to a wrong block and corrupt
the media. This is an indication and no user actually needs this so
let's just drop the support instead of trying to fix it.
Signed-off-by: Jan Kara <jack@suse.cz>

When detecting last recorded block and from it derived anchor block
position, we were mixing unsigned long, u32, and sector_t types. Since
udf supports only 32-bit block numbers this is harmless but sometimes
makes things awkward. Convert everything to udf_pblk_t and also handle
the situation when block device size would not fit into udf_pblk_t.
Signed-off-by: Jan Kara <jack@suse.cz>

When directory's last extent has more that one block and its length is
not multiple of a block side, the code wrongly decided to move to the
next extent instead of processing the last partial block. This led to
directory corruption. Fix the rounding issue.
Signed-off-by: Jan Kara <jack@suse.cz>