linux-stable.git/fs/btrfs, branch linux-3.12.y

posix_acl: Clear SGID bit when setting file permissions

2017-01-27T10:15:59+00:00

commit 073931017b49d9458aa351605b43a7e34598caef upstream.

When file permissions are modified via chmod(2) and the user is not in
the owning group or capable of CAP_FSETID, the setgid bit is cleared in
inode_change_ok().  Setting a POSIX ACL via setxattr(2) sets the file
permissions as well as the new ACL, but doesn't clear the setgid bit in
a similar way; this allows to bypass the check in chmod(2).  Fix that.

Reviewed-by: Christoph Hellwig 
Reviewed-by: Jeff Layton 
Signed-off-by: Jan Kara 
Signed-off-by: Andreas Gruenbacher 
Signed-off-by: Jiri Slaby

Btrfs: fix memory leak in reading btree blocks

2017-01-26T16:22:30+00:00

commit 2571e739677f1e4c0c63f5ed49adcc0857923625 upstream.

So we can read a btree block via readahead or intentional read,
and we can end up with a memory leak when something happens as
follows,
1) readahead starts to read block A but does not wait for read
   completion,
2) btree_readpage_end_io_hook finds that block A is corrupted,
   and it needs to clear all block A's pages' uptodate bit.
3) meanwhile an intentional read kicks in and checks block A's
   pages' uptodate to decide which page needs to be read.
4) when some pages have the uptodate bit during 3)'s check so
   3) doesn't count them for eb->io_pages, but they are later
   cleared by 2) so we has to readpage on the page, we get
   the wrong eb->io_pages which results in a memory leak of
   this block.

This fixes the problem by firstly getting all pages's locking and
then checking pages' uptodate bit.

   t1(readahead)                              t2(readahead endio)                                       t3(the following read)
read_extent_buffer_pages                    end_bio_extent_readpage
  for pg in eb:                                for page 0,1,2 in eb:
      if pg is uptodate:                           btree_readpage_end_io_hook(pg)
          num_reads++                              if uptodate:
  eb->io_pages = num_reads                             SetPageUptodate(pg)              _______________
  for pg in eb:                                for page 3 in eb:                                     read_extent_buffer_pages
       if pg is NOT uptodate:                      btree_readpage_end_io_hook(pg)                       for pg in eb:
           __extent_read_full_page(pg)                 sanity check reports something wrong                 if pg is uptodate:
                                                       clear_extent_buffer_uptodate(eb)                         num_reads++
                                                           for pg in eb:                                eb->io_pages = num_reads
                                                               ClearPageUptodate(page)  _______________
                                                                                                        for pg in eb:
                                                                                                            if pg is NOT uptodate:
                                                                                                                __extent_read_full_page(pg)

So t3's eb->io_pages is not consistent with the number of pages it's reading,
and during endio(), atomic_dec_and_test(&eb->io_pages) will get a negative
number so that we're not able to free the eb.

Signed-off-by: Liu Bo 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba 
Signed-off-by: Jiri Slaby

Btrfs: fix tree search logic when replaying directory entry deletes

2017-01-26T16:22:22+00:00

commit 2a7bf53f577e49c43de4ffa7776056de26db65d9 upstream.

If a log tree has a layout like the following:

leaf N:
        ...
        item 240 key (282 DIR_LOG_ITEM 0) itemoff 8189 itemsize 8
                dir log end 1275809046
leaf N + 1:
        item 0 key (282 DIR_LOG_ITEM 3936149215) itemoff 16275 itemsize 8
                dir log end 18446744073709551615
        ...

When we pass the value 1275809046 + 1 as the parameter start_ret to the
function tree-log.c:find_dir_range() (done by replay_dir_deletes()), we
end up with path->slots[0] having the value 239 (points to the last item
of leaf N, item 240). Because the dir log item in that position has an
offset value smaller than *start_ret (1275809046 + 1) we need to move on
to the next leaf, however the logic for that is wrong since it compares
the current slot to the number of items in the leaf, which is smaller
and therefore we don't lookup for the next leaf but instead we set the
slot to point to an item that does not exist, at slot 240, and we later
operate on that slot which has unexpected content or in the worst case
can result in an invalid memory access (accessing beyond the last page
of leaf N's extent buffer).

So fix the logic that checks when we need to lookup at the next leaf
by first incrementing the slot and only after to check if that slot
is beyond the last item of the current leaf.

Signed-off-by: Robbie Ko 
Reviewed-by: Filipe Manana 
Fixes: e02119d5a7b4 (Btrfs: Add a write ahead tree log to optimize synchronous operations)
Signed-off-by: Filipe Manana 
[Modified changelog for clarity and correctness]
Signed-off-by: Jiri Slaby

Revert "Btrfs: don't delay inode ref updates during log, replay"

2017-01-26T16:22:21+00:00

This reverts commit 644d10716875b24388680925d6c7502420987bfe, upstream
commit 6f8960541b1eb6054a642da48daae2320fddba93.

The original patch for mainline, 6f8960541b1 (Btrfs: don't delay
inode ref updates during log replay) lists 1d52c78afbb (Btrfs: try
not to ENOSPC on log replay) as the only pre-3.18 dependency, but it
also depends on 67de11769bd (Btrfs: introduce the delayed inode ref
deletion for the single link inode), which was introduced in 3.14
and isn't in 3.12.y.

The -stable commit added the check to btrfs_delayed_update_inode,
which may look similar to btrfs_delayed_delete_inode_ref, but it's
only superficial.  The tops of both functions handle typical
delayed node boilerplate.  The upshot is that the patch is harmless
since the caller already checks to see if we're doing log recovery,
so we're not breaking anything.  It should be reverted because it
makes it appear as if this issue was fixed for users who did
backport 67de11769bd, when it is not.

Signed-off-by: Jeff Mahoney 
Signed-off-by: Jiri Slaby

btrfs: ensure that file descriptor used with subvol ioctls is a dir

2016-10-06T06:21:58+00:00

commit 325c50e3cebb9208009083e841550f98a863bfa0 upstream.

If the subvol/snapshot create/destroy ioctls are passed a regular file
with execute permissions set, we'll eventually Oops while trying to do
inode->i_op->lookup via lookup_one_len.

This patch ensures that the file descriptor refers to a directory.

Fixes: cb8e70901d (Btrfs: Fix subvolume creation locking rules)
Fixes: 76dda93c6a (Btrfs: add snapshot/subvolume destroy ioctl)
Signed-off-by: Jeff Mahoney 
Signed-off-by: Chris Mason 
Signed-off-by: Jiri Slaby

Btrfs: skip locking when searching commit root

2016-04-11T14:43:49+00:00

commit e84752d434b5cca0869e906e7b94d0531b25c6d3 upstream.

We won't change commit root, skip locking dance with commit root
when walking backrefs, this can speed up btrfs send operations.

Signed-off-by: Wang Shilong 
Signed-off-by: Josef Bacik 
Signed-off-by: Jiri Slaby

Btrfs: fix number of transaction units required to create symlink

2016-03-03T11:46:01+00:00

commit 9269d12b2d57d9e3d13036bb750762d1110d425c upstream.

We weren't accounting for the insertion of an inline extent item for the
symlink inode nor that we need to update the parent inode item (through
the call to btrfs_add_nondir()). So fix this by including two more
transaction units.

Signed-off-by: Filipe Manana 
Signed-off-by: Jiri Slaby

Btrfs: send, don't BUG_ON() when an empty symlink is found

2016-03-03T11:46:00+00:00

commit a879719b8c90e15c9e7fa7266d5e3c0ca962f9df upstream.

When a symlink is successfully created it always has an inline extent
containing the source path. However if an error happens when creating
the symlink, we can leave in the subvolume's tree a symlink inode without
any such inline extent item - this happens if after btrfs_symlink() calls
btrfs_end_transaction() and before it calls the inode eviction handler
(through the final iput() call), the transaction gets committed and a
crash happens before the eviction handler gets called, or if a snapshot
of the subvolume is made before the eviction handler gets called. Sadly
we can't just avoid this by making btrfs_symlink() call
btrfs_end_transaction() after it calls the eviction handler, because the
later can commit the current transaction before it removes any items from
the subvolume tree (if it encounters ENOSPC errors while reserving space
for removing all the items).

So make send fail more gracefully, with an -EIO error, and print a
message to dmesg/syslog informing that there's an empty symlink inode,
so that the user can delete the empty symlink or do something else
about it.

Reported-by: Stephen R. van den Berg 
Signed-off-by: Filipe Manana 
Signed-off-by: Jiri Slaby

Btrfs: igrab inode in writepage

2016-03-03T11:46:00+00:00

commit be7bd730841e69fe8f70120098596f648cd1f3ff upstream.

We hit this panic on a few of our boxes this week where we have an
ordered_extent with an NULL inode.  We do an igrab() of the inode in writepages,
but weren't doing it in writepage which can be called directly from the VM on
dirty pages.  If the inode has been unlinked then we could have I_FREEING set
which means igrab() would return NULL and we get this panic.  Fix this by trying
to igrab in btrfs_writepage, and if it returns NULL then just redirty the page
and return AOP_WRITEPAGE_ACTIVATE; so the VM knows it wasn't successful.  Thanks,

Signed-off-by: Josef Bacik 
Reviewed-by: Liu Bo 
Signed-off-by: David Sterba 
Signed-off-by: Jiri Slaby

Btrfs: add missing brelse when superblock checksum fails

2016-03-03T11:46:00+00:00

commit b2acdddfad13c38a1e8b927d83c3cf321f63601a upstream.

Looks like oversight, call brelse() when checksum fails. Further down the
code, in the non error path, we do call brelse() and so we don't see
brelse() in the goto error paths.

Signed-off-by: Anand Jain 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba 
Signed-off-by: Jiri Slaby