Currently mapping of blocks for DAX writes happen with
EXT4_GET_BLOCKS_PRE_IO flag set. That has a result that each
ext4_map_blocks() call creates a separate written extent, although it
could be merged to the neighboring extents in the extent tree.  The
reason for using this flag is that in case the extent is unwritten, we
need to convert it to written one and zero it out. However this "convert
mapped range to written" operation is already implemented by
ext4_map_blocks() for the case of data writes into unwritten extent. So
just use flags for that mode of operation, simplify the code, and avoid
unnecessary split extents.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Implement DAX writes using the new iomap infrastructure instead of
overloading the direct IO path.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Use iomap infrastructure for zeroing blocks when in DAX mode.
ext4_iomap_begin() handles read requests just fine and that's all that
is needed for iomap_zero_range().
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Implement basic iomap_begin function that handles reading and use it for
DAX reads.
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Currently we have S_DAX set inode->i_flags for a regular file whenever
ext4 is mounted with dax mount option. However in some cases we cannot
really do DAX - e.g. when inode is marked to use data journalling, when
inode data is being encrypted, or when inode is stored inline. Make sure
S_DAX flag is appropriately set/cleared in these cases.
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Factor out checks of 'from' and whether we are overwriting out of
ext4_file_write_iter() so that the function is easier to follow.
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

The commit "ext4: sanity check the block and cluster size at mount
time" should prevent any problems, but in case the superblock is
modified while the file system is mounted, add an extra safety check
to make sure we won't overrun the allocated buffer.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org

Centralize the checks for inodes_per_block and be more strict to make
sure the inodes_per_block_group can't end up being zero.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Cc: stable@vger.kernel.org

Fix a large number of problems with how we handle mount options in the
superblock.  For one, if the string in the superblock is long enough
that it is not null terminated, we could run off the end of the string
and try to interpret superblocks fields as characters.  It's unlikely
this will cause a security problem, but it could result in an invalid
parse.  Also, parse_options is destructive to the string, so in some
cases if there is a comma-separated string, it would be modified in
the superblock.  (Fortunately it only happens on file systems with a
1k block size.)
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org

If the block size or cluster size is insane, reject the mount.  This
is important for security reasons (although we shouldn't be just
depending on this check).

Ref: http://www.securityfocus.com/archive/1/539661
Ref: https://bugzilla.redhat.com/show_bug.cgi?id=1332506Reported-by: Borislav Petkov <bp@alien8.de>
Reported-by: Nikolay Borisov <kernel@kyup.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org

The parameter "handle" isn't used.
Signed-off-by: Eric Whitney <enwlinux@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Runs of xfstest ext4/022 on nojournal file systems result in failures
because the inodes of some of its test files do not expand as expected.
The cause is a conditional in ext4_mark_inode_dirty() that prevents inode
expansion unless the test file system has a journal.  Remove this
unnecessary restriction.
Signed-off-by: Eric Whitney <enwlinux@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

CURRENT_TIME_SEC and CURRENT_TIME are not y2038 safe.
current_time() will be transitioned to be y2038 safe
along with vfs.

current_time() returns timestamps according to the
granularities set in the super_block.
The granularity check in ext4_current_time() to call
current_time() or CURRENT_TIME_SEC is not required.
Use current_time() directly to obtain timestamps
unconditionally, and remove ext4_current_time().

Quota files are assumed to be on the same filesystem.
Hence, use current_time() for these files as well.
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>

The number of 'counters' elements needed in 'struct sg' is
super_block->s_blocksize_bits + 2. Presently we have 16 'counters'
elements in the array. This is insufficient for block sizes >= 32k. In
such cases the memcpy operation performed in ext4_mb_seq_groups_show()
would cause stack memory corruption.

Fixes: c9de560dSigned-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: stable@vger.kernel.org

'border' variable is set to a value of 2 times the block size of the
underlying filesystem. With 64k block size, the resulting value won't
fit into a 16-bit variable. Hence this commit changes the data type of
'border' to 'unsigned int'.

Fixes: c9de560dSigned-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Cc: stable@vger.kernel.org

If there is an error reported in mballoc via ext4_grp_locked_error(),
the code is holding a spinlock, so ext4_commit_super() must not try to
lock the buffer head, or else it will trigger a BUG:

  BUG: sleeping function called from invalid context at ./include/linux/buffer_head.h:358
  in_atomic(): 1, irqs_disabled(): 0, pid: 993, name: mount
  CPU: 0 PID: 993 Comm: mount Not tainted 4.9.0-rc1-clouder1 #62
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.8.1-0-g4adadbd-20150316_085822-nilsson.home.kraxel.org 04/01/2014
   ffff880006423548 ffffffff81318c89 ffffffff819ecdd0 0000000000000166
   ffff880006423558 ffffffff810810b0 ffff880006423580 ffffffff81081153
   ffff880006e5a1a0 ffff88000690e400 0000000000000000 ffff8800064235c0
  Call Trace:
    [<ffffffff81318c89>] dump_stack+0x67/0x9e
    [<ffffffff810810b0>] ___might_sleep+0xf0/0x140
    [<ffffffff81081153>] __might_sleep+0x53/0xb0
    [<ffffffff8126c1dc>] ext4_commit_super+0x19c/0x290
    [<ffffffff8126e61a>] __ext4_grp_locked_error+0x14a/0x230
    [<ffffffff81081153>] ? __might_sleep+0x53/0xb0
    [<ffffffff812822be>] ext4_mb_generate_buddy+0x1de/0x320

Since ext4_grp_locked_error() calls ext4_commit_super with sync == 0
(and it is the only caller which does so), avoid locking and unlocking
the buffer in this case.

This can result in races with ext4_commit_super() if there are other
problems (which is what commit 4743f839 was trying to address),
but a Warning is better than BUG.

Fixes: 4743f839
Cc: stable@vger.kernel.org # 4.9
Reported-by: Nikolay Borisov <kernel@kyup.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>

Return errors to the caller instead of declaring the file system
corrupted.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>

This allows us to properly propagate errors back up to
ext4_truncate()'s callers.  This also means we no longer have to
silently ignore some errors (e.g., when trying to add the inode to the
orphan inode list).
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>

With the new (in 4.9) option to use a virtually-mapped stack
(CONFIG_VMAP_STACK), stack buffers cannot be used as input/output for
the scatterlist crypto API because they may not be directly mappable to
struct page.  get_crypt_info() was using a stack buffer to hold the
output from the encryption operation used to derive the per-file key.
Fix it by using a heap buffer.

This bug could most easily be observed in a CONFIG_DEBUG_SG kernel
because this allowed the BUG in sg_set_buf() to be triggered.

Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

With the new (in 4.9) option to use a virtually-mapped stack
(CONFIG_VMAP_STACK), stack buffers cannot be used as input/output for
the scatterlist crypto API because they may not be directly mappable to
struct page.  For short filenames, fname_encrypt() was encrypting a
stack buffer holding the padded filename.  Fix it by encrypting the
filename in-place in the output buffer, thereby making the temporary
buffer unnecessary.

This bug could most easily be observed in a CONFIG_DEBUG_SG kernel
because this allowed the BUG in sg_set_buf() to be triggered.

Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Avoid re-use of page index as tweak for AES-XTS when multiple parts of
same page are encrypted. This will happen on multiple (partial) calls of
fscrypt_encrypt_page on same page.
page->index is only valid for writeback pages.
Signed-off-by: David Gstir <david@sigma-star.at>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Some filesystems, such as UBIFS, maintain a const pointer for struct
inode.
Signed-off-by: David Gstir <david@sigma-star.at>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Not all filesystems work on full pages, thus we should allow them to
hand partial pages to fscrypt for en/decryption.
Signed-off-by: David Gstir <david@sigma-star.at>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Some filesystem might pass pages which do not have page->mapping->host
set to the encrypted inode. We want the caller to explicitly pass the
corresponding inode.
Signed-off-by: David Gstir <david@sigma-star.at>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

ext4 and f2fs require a bounce page when encrypting pages. However, not
all filesystems will need that (eg. UBIFS). This is handled via a
flag on fscrypt_operations where a fs implementation can select in-place
encryption over using a bounce page (which is the default).
Signed-off-by: David Gstir <david@sigma-star.at>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Introduce a flag telling iomap operations whether they are handling a
fault or other IO. That may influence behavior wrt inode size and
similar things.
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>

Now that DAX PMD faults are once again working and are now participating in
DAX's radix tree locking scheme, allow their config option to be enabled.
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dave Chinner <david@fromorbit.com>

Switch xfs_filemap_pmd_fault() from using dax_pmd_fault() to the new and
improved dax_iomap_pmd_fault().  Also, now that it has no more users,
remove xfs_get_blocks_dax_fault().
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dave Chinner <david@fromorbit.com>

DAX PMDs have been disabled since Jan Kara introduced DAX radix tree based
locking.  This patch allows DAX PMDs to participate in the DAX radix tree
based locking scheme so that they can be re-enabled using the new struct
iomap based fault handlers.

There are currently three types of DAX 4k entries: 4k zero pages, 4k DAX
mappings that have an associated block allocation, and 4k DAX empty
entries.  The empty entries exist to provide locking for the duration of a
given page fault.

This patch adds three equivalent 2MiB DAX entries: Huge Zero Page (HZP)
entries, PMD DAX entries that have associated block allocations, and 2 MiB
DAX empty entries.

Unlike the 4k case where we insert a struct page* into the radix tree for
4k zero pages, for HZP we insert a DAX exceptional entry with the new
RADIX_DAX_HZP flag set.  This is because we use a single 2 MiB zero page in
every 2MiB hole mapping, and it doesn't make sense to have that same struct
page* with multiple entries in multiple trees.  This would cause contention
on the single page lock for the one Huge Zero Page, and it would break the
page->index and page->mapping associations that are assumed to be valid in
many other places in the kernel.

One difficult use case is when one thread is trying to use 4k entries in
radix tree for a given offset, and another thread is using 2 MiB entries
for that same offset.  The current code handles this by making the 2 MiB
user fall back to 4k entries for most cases.  This was done because it is
the simplest solution, and because the use of 2MiB pages is already
opportunistic.

If we were to try to upgrade from 4k pages to 2MiB pages for a given range,
we run into the problem of how we lock out 4k page faults for the entire
2MiB range while we clean out the radix tree so we can insert the 2MiB
entry.  We can solve this problem if we need to, but I think that the cases
where both 2MiB entries and 4K entries are being used for the same range
will be rare enough and the gain small enough that it probably won't be
worth the complexity.
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dave Chinner <david@fromorbit.com>

No functional change.

The static functions put_locked_mapping_entry() and
put_unlocked_mapping_entry() will soon be used in error cases in
grab_mapping_entry(), so move their definitions above this function.
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dave Chinner <david@fromorbit.com>

The RADIX_DAX_* defines currently mostly live in fs/dax.c, with just
RADIX_DAX_ENTRY_LOCK being in include/linux/dax.h so it can be used in
mm/filemap.c.  When we add PMD support, though, mm/filemap.c will also need
access to the RADIX_DAX_PTE type so it can properly construct a 4k sized
empty entry.

Instead of shifting the defines between dax.c and dax.h as they are
individually used in other code, just move them wholesale to dax.h so
they'll be available when we need them.
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dave Chinner <david@fromorbit.com>

Currently iomap_end() doesn't do anything for DAX page faults for both ext2
and XFS.  ext2_iomap_end() just checks for a write underrun, and
xfs_file_iomap_end() checks to see if it needs to finish a delayed
allocation.  However, in the future iomap_end() calls might be needed to
make sure we have balanced allocations, locks, etc.  So, add calls to
iomap_end() with appropriate error handling to dax_iomap_fault().
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Suggested-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dave Chinner <david@fromorbit.com>

To be able to correctly calculate the sector from a file position and a
struct iomap there is a complex little bit of logic that currently happens
in both dax_iomap_actor() and dax_iomap_fault().  This will need to be
repeated yet again in the DAX PMD fault handler when it is added, so break
it out into a helper function.
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dave Chinner <david@fromorbit.com>

The recently added DAX functions that use the new struct iomap data
structure were named iomap_dax_rw(), iomap_dax_fault() and
iomap_dax_actor().  These are actually defined in fs/dax.c, though, so
should be part of the "dax" namespace and not the "iomap" namespace.
Rename them to dax_iomap_rw(), dax_iomap_fault() and dax_iomap_actor()
respectively.
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Suggested-by: Dave Chinner <david@fromorbit.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dave Chinner <david@fromorbit.com>

dax_pmd_fault() is the old struct buffer_head + get_block_t based 2 MiB DAX
fault handler.  This fault handler has been disabled for several kernel
releases, and support for PMDs will be reintroduced using the struct iomap
interface instead.
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dave Chinner <david@fromorbit.com>

DAX radix tree locking currently locks entries based on the unique
combination of the 'mapping' pointer and the pgoff_t 'index' for the entry.
This works for PTEs, but as we move to PMDs we will need to have all the
offsets within the range covered by the PMD to map to the same bit lock.
To accomplish this, for ranges covered by a PMD entry we will instead lock
based on the page offset of the beginning of the PMD entry.  The 'mapping'
pointer is still used in the same way.
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dave Chinner <david@fromorbit.com>

No functional change.

Consistently use the variable name 'entry' instead of 'ret' for DAX radix
tree entries.  This was already happening in most of the code, so update
get_unlocked_mapping_entry(), grab_mapping_entry() and
dax_unlock_mapping_entry().
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dave Chinner <david@fromorbit.com>

Don't take down the kernel if we get an invalid 'from' and 'length'
argument pair.  Just warn once and return an error.
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dave Chinner <david@fromorbit.com>