linux-toradex.git, branch v4.9.8

Linux 4.9.8

2017-02-04T08:47:29+00:00

xfs: fix bmv_count confusion w/ shared extents

2017-02-04T08:47:13+00:00

commit c364b6d0b6cda1cd5d9ab689489adda3e82529aa upstream.

In a bmapx call, bmv_count is the total size of the array, including the
zeroth element that userspace uses to supply the search key.  The output
array starts at offset 1 so that we can set up the user for the next
invocation.  Since we now can split an extent into multiple bmap records
due to shared/unshared status, we have to be careful that we don't
overflow the output array.

In the original patch f86f403794b ("xfs: teach get_bmapx about shared
extents and the CoW fork") I used cur_ext (the output index) to check
for overflows, albeit with an off-by-one error.  Since nexleft no longer
describes the number of unfilled slots in the output, we can rip all
that out and use cur_ext for the overflow check directly.

Failure to do this causes heap corruption in bmapx callers such as
xfs_io and xfs_scrub.  xfs/328 can reproduce this problem.

Reviewed-by: Eric Sandeen 
Signed-off-by: Darrick J. Wong 
Signed-off-by: Greg Kroah-Hartman

xfs: clear _XBF_PAGES from buffers when readahead page

2017-02-04T08:47:12+00:00

commit 2aa6ba7b5ad3189cc27f14540aa2f57f0ed8df4b upstream.

If we try to allocate memory pages to back an xfs_buf that we're trying
to read, it's possible that we'll be so short on memory that the page
allocation fails.  For a blocking read we'll just wait, but for
readahead we simply dump all the pages we've collected so far.

Unfortunately, after dumping the pages we neglect to clear the
_XBF_PAGES state, which means that the subsequent call to xfs_buf_free
thinks that b_pages still points to pages we own.  It then double-frees
the b_pages pages.

This results in screaming about negative page refcounts from the memory
manager, which xfs oughtn't be triggering.  To reproduce this case,
mount a filesystem where the size of the inodes far outweighs the
availalble memory (a ~500M inode filesystem on a VM with 300MB memory
did the trick here) and run bulkstat in parallel with other memory
eating processes to put a huge load on the system.  The "check summary"
phase of xfs_scrub also works for this purpose.

Signed-off-by: Darrick J. Wong 
Reviewed-by: Eric Sandeen 
Signed-off-by: Greg Kroah-Hartman

xfs: extsize hints are not unlikely in xfs_bmap_btalloc

2017-02-04T08:47:12+00:00

commit 493611ebd62673f39e2f52c2561182c558a21cb6 upstream.

With COW files they are the hotpath, just like for files with the
extent size hint attribute.  We really shouldn't micro-manage anything
but failure cases with unlikely.

Additionally Arnd Bergmann recently reported that one of these two
unlikely annotations causes link failures together with an upcoming
kernel instrumentation patch, so let's get rid of it ASAP.

Signed-off-by: Christoph Hellwig 
Reported-by: Arnd Bergmann 
Reviewed-by: Darrick J. Wong 
Signed-off-by: Darrick J. Wong 
Signed-off-by: Greg Kroah-Hartman

xfs: remove racy hasattr check from attr ops

2017-02-04T08:47:12+00:00

commit 5a93790d4e2df73e30c965ec6e49be82fc3ccfce upstream.

xfs_attr_[get|remove]() have unlocked attribute fork checks to optimize
away a lock cycle in cases where the fork does not exist or is otherwise
empty. This check is not safe, however, because an attribute fork short
form to extent format conversion includes a transient state that causes
the xfs_inode_hasattr() check to fail. Specifically,
xfs_attr_shortform_to_leaf() creates an empty extent format attribute
fork and then adds the existing shortform attributes to it.

This means that lookup of an existing xattr can spuriously return
-ENOATTR when racing against a setxattr that causes the associated
format conversion. This was originally reproduced by an untar on a
particularly configured glusterfs volume, but can also be reproduced on
demand with properly crafted xattr requests.

The format conversion occurs under the exclusive ilock. xfs_attr_get()
and xfs_attr_remove() already have the proper locking and checks further
down in the functions to handle this situation correctly. Drop the
unlocked checks to avoid the spurious failure and rely on the existing
logic.

Signed-off-by: Brian Foster 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Darrick J. Wong 
Signed-off-by: Darrick J. Wong 
Signed-off-by: Greg Kroah-Hartman

xfs: verify dirblocklog correctly

2017-02-04T08:47:12+00:00

commit 83d230eb5c638949350f4761acdfc0af5cb1bc00 upstream.

sb_dirblklog is added to sb_blocklog to compute the directory block size
in bytes.  Therefore, we must compare the sum of both those values
against XFS_MAX_BLOCKSIZE_LOG, not just dirblklog.

Signed-off-by: Darrick J. Wong 
Reviewed-by: Eric Sandeen 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Greg Kroah-Hartman

xfs: fix COW writeback race

2017-02-04T08:47:12+00:00

commit d2b3964a0780d2d2994eba57f950d6c9fe489ed8 upstream.

Due to the way how xfs_iomap_write_allocate tries to convert the whole
found extents from delalloc to real space we can run into a race
condition with multiple threads doing writes to this same extent.
For the non-COW case that is harmless as the only thing that can happen
is that we call xfs_bmapi_write on an extent that has already been
converted to a real allocation.  For COW writes where we move the extent
from the COW to the data fork after I/O completion the race is, however,
not quite as harmless.  In the worst case we are now calling
xfs_bmapi_write on a region that contains hole in the COW work, which
will trip up an assert in debug builds or lead to file system corruption
in non-debug builds.  This seems to be reproducible with workloads of
small O_DSYNC write, although so far I've not managed to come up with
a with an isolated reproducer.

The fix for the issue is relatively simple:  tell xfs_bmapi_write
that we are only asked to convert delayed allocations and skip holes
in that case.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Brian Foster 
Reviewed-by: Darrick J. Wong 
Signed-off-by: Darrick J. Wong 
Signed-off-by: Greg Kroah-Hartman

xfs: fix xfs_mode_to_ftype() prototype

2017-02-04T08:47:12+00:00

commit fd29f7af75b7adf250beccffa63746c6a88e2b74 upstream.

A harmless warning just got introduced:

fs/xfs/libxfs/xfs_dir2.h:40:8: error: type qualifiers ignored on function return type [-Werror=ignored-qualifiers]

Removing the 'const' modifier avoids the warning and has no
other effect.

Fixes: 1fc4d33fed12 ("xfs: replace xfs_mode_to_ftype table with switch statement")
Signed-off-by: Arnd Bergmann 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Darrick J. Wong 
Signed-off-by: Darrick J. Wong 
Signed-off-by: Greg Kroah-Hartman

xfs: don't wrap ID in xfs_dq_get_next_id

2017-02-04T08:47:12+00:00

commit 657bdfb7f5e68ca5e2ed009ab473c429b0d6af85 upstream.

The GETNEXTQOTA ioctl takes whatever ID is sent in,
and looks for the next active quota for an user
equal or higher to that ID.

But if we are at the maximum ID and then ask for the "next"
one, we may wrap back to zero.  In this case, userspace
may loop forever, because it will start querying again
at zero.

We'll fix this in userspace as well, but for the kernel,
return -ENOENT if we ask for the next quota ID
past UINT_MAX so the caller knows to stop.

Signed-off-by: Eric Sandeen 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Darrick J. Wong 
Signed-off-by: Darrick J. Wong 
Signed-off-by: Greg Kroah-Hartman

xfs: sanity check inode di_mode

2017-02-04T08:47:12+00:00

commit a324cbf10a3c67aaa10c9f47f7b5801562925bc2 upstream.

Check for invalid file type in xfs_dinode_verify()
and fail to load the inode structure from disk.

Reviewed-by: Darrick J. Wong 
Signed-off-by: Amir Goldstein 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Darrick J. Wong 
Signed-off-by: Darrick J. Wong 
Signed-off-by: Greg Kroah-Hartman