Add locking to ensure that DAX faults are isolated from ext2 operations
that modify the data blocks allocation for an inode. This is intended to
be analogous to the work being done in XFS by Dave Chinner:
http://www.spinics.net/lists/linux-fsdevel/msg90260.html
Compared with XFS the ext2 case is greatly simplified by the fact that ext2
already allocates and zeros new blocks before they are returned as part of
ext2_get_block(), so DAX doesn't need to worry about getting unmapped or
unwritten buffer heads.
This means that the only work we need to do in ext2 is to isolate the DAX
faults from inode block allocation changes. I believe this just means that
we need to isolate the DAX faults from truncate operations.
The newly introduced dax_sem is intended to replicate the protection
offered by i_mmaplock in XFS. In addition to truncate the i_mmaplock also
protects XFS operations like hole punching, fallocate down, extent
manipulation IOCTLS like xfs_ioc_space() and extent swapping. Truncate is
the only one of these operations supported by ext2.
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Jan Kara <jack@suse.com>
The original dax patchset split the ext2/4_file_operations because of the
two NULL splice_read/splice_write in the dax case.
In the vfs if splice_read/splice_write are NULL we then call
default_splice_read/write.
What we do here is make generic_file_splice_read aware of IS_DAX() so the
original ext2/4_file_operations can be used as is.
For write it appears that iter_file_splice_write is just fine. It uses
the regular f_op->write(file,..) or new_sync_write(file, ...).
Signed-off-by: Boaz Harrosh <boaz@plexistor.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Btrfs needs to be able to control how filemap_write_and_wait_range() is called
in fsync to make it less of a painful operation, so push down taking i_mutex and
the calling of filemap_write_and_wait() down into the ->fsync() handlers. Some
file systems can drop taking the i_mutex altogether it seems, like ext3 and
ocfs2. For correctness sake I just pushed everything down in all cases to make
sure that we keep the current behavior the same for everybody, and then each
individual fs maintainer can make up their mind about what to do from there.
Thanks,
Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
As the result of conversions, there are no users of ext2 non-atomic bit
operations except for ext2 filesystem itself. Now we can put them into
architecture independent code in ext2 filesystem, and remove from
asm/bitops.h for all architectures.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
SELinux would like to implement a new labeling behavior of newly created
inodes. We currently label new inodes based on the parent and the creating
process. This new behavior would also take into account the name of the
new object when deciding the new label. This is not the (supposed) full path,
just the last component of the path.
This is very useful because creating /etc/shadow is different than creating
/etc/passwd but the kernel hooks are unable to differentiate these
operations. We currently require that userspace realize it is doing some
difficult operation like that and than userspace jumps through SELinux hoops
to get things set up correctly. This patch does not implement new
behavior, that is obviously contained in a seperate SELinux patch, but it
does pass the needed name down to the correct LSM hook. If no such name
exists it is fine to pass NULL.
Signed-off-by: Eric Paris <eparis@redhat.com>
Add a new helper to write out the inode using the writeback code,
that is including the correct dirty bit and list manipulation. A few
of filesystems already opencode this, and a lot of others should be
using it instead of using write_inode_now which also writes out the
data.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
For filesystem that implement directories in pagecache we call
block_write_begin with an already allocated page for this code, while the
normal regular file write path uses the default block_write_begin behaviour.
Get rid of the __foofs_write_begin helper and opencode the normal write_begin
call in foofs_write_begin, while adding a new foofs_prepare_chunk helper for
the directory code. The added benefit is that foofs_prepare_chunk has
a much saner calling convention.
Note that the interruptible flag passed into block_write_begin is always
ignored if we already pass in a page (see next patch for details), and
we never were doing truncations of exessive blocks for this case either so we
can switch directly to block_write_begin_newtrunc.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This gives the filesystem more information about the writeback that
is happening. Trond requested this for the NFS unstable write handling,
and other filesystems might benefit from this too by beeing able to
distinguish between the different callers in more detail.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
When an IO error happens while writing metadata buffers, we should better
report it and call ext2_error since the filesystem is probably no longer
consistent. Sometimes such IO errors happen while flushing thread does
background writeback, the buffer gets later evicted from memory, and thus
the only trace of the error remains as AS_EIO bit set in blockdevice's
mapping. So we check this bit in ext2_fsync and report the error although
we cannot be really sure which buffer we failed to write.
Signed-off-by: Jan Kara <jack@suse.cz>
Cc: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
One of our users is complaining that his backup tool is upset on ext2
(while it's happy on ext3, xfs, ...) because of the mtime change.
The problem is:
mkdir foo
mkdir bar
mkdir foo/a
Now under ext2:
mv foo/a foo/b
changes mtime of 'foo/a' (foo/b after the move). That does not really
make sense and it does not happen under any other filesystem I've seen.
More complicated is:
mv foo/a bar/a
This changes mtime of foo/a (bar/a after the move) and it makes some
sense since we had to update parent directory pointer of foo/a. But
again, no other filesystem does this. So after some thoughts I'd vote
for consistency and change ext2 to behave the same as other filesystems.
Do not update mtime of a moved directory. Specs don't say anything
about it (neither that it should, nor that it should not be updated) and
other common filesystems (ext3, ext4, xfs, reiserfs, fat, ...) don't do
it. So let's become more consistent.
Spotted by ronny.pretzsch@dfs.de, initial fix by Jörn Engel.
Reported-by: <ronny.pretzsch@dfs.de>
Cc: <hare@suse.de>
Cc: Jörn Engel <joern@logfs.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Ross Zwisler
Boaz Harrosh
Matthew Wilcox
Jan Kara
Eric W. Biederman
Al Viro
Joe Perches
Josef Bacik
Akinobu Mita
Eric Paris
Christoph Hellwig
npiggin@suse.de
Alexey Fisher
Ali Gholami Rudi