XFS uses the internal tmpfile() infrastructure for the whiteout inode
used for RENAME_WHITEOUT operations. For tmpfile inodes, XFS allocates
the inode, drops di_nlink, adds the inode to the agi unlinked list,
calls d_tmpfile() which correspondingly drops i_nlink of the vfs inode,
and then finishes the common inode setup (e.g., clear I_NEW and unlock).
The d_tmpfile() call was originally made inxfs_create_tmpfile(), but was
pulled up out of that function as part of the following commit to
resolve a deadlock issue:
330033d6 xfs: fix tmpfile/selinux deadlock and initialize security
As a result, callers of xfs_create_tmpfile() are responsible for either
calling d_tmpfile() or fixing up i_nlink appropriately. The whiteout
tmpfile allocation helper does neither. As a result, the vfs ->i_nlink
becomes inconsistent with the on-disk ->di_nlink once xfs_rename() links
it back into the source dentry and calls xfs_bumplink().
Update the assert in xfs_rename() to help detect this problem in the
future and update xfs_rename_alloc_whiteout() to decrement the link
count as part of the manual tmpfile inode setup.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
xfs_attr_inactive() is supposed to clean up the attribute fork when
the inode is being freed. While it removes attribute fork extents,
it completely ignores attributes in local format, which means that
there can still be active attributes on the inode after
xfs_attr_inactive() has run.
This leads to problems with concurrent inode writeback - the in-core
inode attribute fork is removed without locking on the assumption
that nothing will be attempting to access the attribute fork after a
call to xfs_attr_inactive() because it isn't supposed to exist on
disk any more.
To fix this, make xfs_attr_inactive() completely remove all traces
of the attribute fork from the inode, regardless of it's state.
Further, also remove the in-core attribute fork structure safely so
that there is nothing further that needs to be done by callers to
clean up the attribute fork. This means we can remove the in-core
and on-disk attribute forks atomically.
Also, on error simply remove the in-memory attribute fork. There's
nothing that can be done with it once we have failed to remove the
on-disk attribute fork, so we may as well just blow it away here
anyway.
cc: <stable@vger.kernel.org> # 3.12 to 4.0
Reported-by: Waiman Long <waiman.long@hp.com>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
new_parent and src_is_directory are only used in 0/1 context.
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Whiteouts are used by overlayfs - it has a crazy convention that a
whiteout is a character device inode with a major:minor of 0:0.
Because it's not documented anywhere, here's an example of what
RENAME_WHITEOUT does on ext4:
# echo foo > /mnt/scratch/foo
# echo bar > /mnt/scratch/bar
# ls -l /mnt/scratch
total 24
-rw-r--r-- 1 root root 4 Feb 11 20:22 bar
-rw-r--r-- 1 root root 4 Feb 11 20:22 foo
drwx------ 2 root root 16384 Feb 11 20:18 lost+found
# src/renameat2 -w /mnt/scratch/foo /mnt/scratch/bar
# ls -l /mnt/scratch
total 20
-rw-r--r-- 1 root root 4 Feb 11 20:22 bar
c--------- 1 root root 0, 0 Feb 11 20:23 foo
drwx------ 2 root root 16384 Feb 11 20:18 lost+found
# cat /mnt/scratch/bar
foo
#
In XFS rename terms, the operation that has been done is that source
(foo) has been moved to the target (bar), which is like a nomal
rename operation, but rather than the source being removed, it have
been replaced with a whiteout.
We can't allocate whiteout inodes within the rename transaction due
to allocation being a multi-commit transaction: rename needs to
be a single, atomic commit. Hence we have several options here, form
most efficient to least efficient:
- use DT_WHT in the target dirent and do no whiteout inode
allocation. The main issue with this approach is that we need
hooks in lookup to create a virtual chardev inode to present
to userspace and in places where we might need to modify the
dirent e.g. unlink. Overlayfs also needs to be taught about
DT_WHT. Most invasive change, lowest overhead.
- create a special whiteout inode in the root directory (e.g. a
".wino" dirent) and then hardlink every new whiteout to it.
This means we only need to create a single whiteout inode, and
rename simply creates a hardlink to it. We can use DT_WHT for
these, though using DT_CHR means we won't have to modify
overlayfs, nor anything in userspace. Downside is we have to
look up the whiteout inode on every operation and create it if
it doesn't exist.
- copy ext4: create a special whiteout chardev inode for every
whiteout. This is more complex than the above options because
of the lack of atomicity between inode creation and the rename
operation, requiring us to create a tmpfile inode and then
linking it into the directory structure during the rename. At
least with a tmpfile inode crashes between the create and
rename doesn't leave unreferenced inodes or directory
pollution around.
By far the simplest thing to do in the short term is to copy ext4.
While it is the most inefficient way of supporting whiteouts, but as
an initial implementation we can simply reuse existing functions and
add a small amount of extra code the the rename operation.
When we get full whiteout support in the VFS (via the dentry cache)
we can then look to supporting DT_WHT method outlined as the first
method of supporting whiteouts. But until then, we'll stick with
what overlayfs expects us to be: dumb and stupid.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Now that xfs_finish_rename() exists, there is no reason for
xfs_cross_rename() to return to xfs_rename() to finish off the
rename transaction. Drive the completion code into
xfs_cross_rename() and handle all errors there so as to simplify
the xfs_rename() code.
Further, push the rename exchange target_ip check to early in the
rename code so as to make the error handling easy and obviously
correct.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Rather than use a jump label for the final transaction commit in
the rename, factor it into a simple helper function and call it
appropriately. This slightly reduces the spaghetti nature of
xfs_rename.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
The jump labels are ambiguous and unclear and some of the error
paths are used inconsistently. Rules for error jumps are:
- use out_trans_cancel for unmodified transaction context
- use out_bmap_cancel on ENOSPC errors
- use out_trans_abort when transaction is likely to be dirty.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
When doing RENAME_WHITEOUT, we now have to lock 5 inodes into the
rename transaction. This means we need to update
xfs_sort_for_rename() and xfs_lock_inodes() to handle up to 5
inodes. Because of the vagaries of rename, this means we could have
anywhere between 3 and 5 inodes locked into the transaction....
While xfs_lock_inodes() does not need anything other than an assert
telling us we are passing more inodes that we ever thought we should
see, it could do with a logic rework to remove all the indenting.
This is not a functional change - it just makes the code a lot
easier to read.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
We shouldn't get here with RENAME_EXCHANGE set and no
target_ip, but let's be defensive, because xfs_cross_rename()
will dereference it.
Spotted by Coverity.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Al Viro noticed a generic set of issues to do with filehandle lookup
racing with dentry cache setup. They involve a filehandle lookup
occurring while an inode is being created and the filehandle lookup
racing with the dentry creation for the real file. This can lead to
multiple dentries for the one path being instantiated. There are a
host of other issues around this same set of paths.
The underlying cause is that file handle lookup only waits on inode
cache instantiation rather than full dentry cache instantiation. XFS
is mostly immune to the problems discovered due to it's own internal
inode cache, but there are a couple of corner cases where races can
happen.
We currently clear the XFS_INEW flag when the inode is fully set up
after insertion into the cache. Newly allocated inodes are inserted
locked and so aren't usable until the allocation transaction
commits. This, however, occurs before the dentry and security
information is fully initialised and hence the inode is unlocked and
available for lookups to find too early.
To solve the problem, only clear the XFS_INEW flag for newly created
inodes once the dentry is fully instantiated. This means lookups
will retry until the XFS_INEW flag is removed from the inode and
hence avoids the race conditions in questions.
THis also means that xfs_create(), xfs_create_tmpfile() and
xfs_symlink() need to finish the setup of the inode in their error
paths if we had allocated the inode but failed later in the creation
process. xfs_symlink(), in particular, needed a lot of help to make
it's error handling match that of xfs_create().
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Right now we cannot serialise mmap against truncate or hole punch
sanely. ->page_mkwrite is not able to take locks that the read IO
path normally takes (i.e. the inode iolock) because that could
result in lock inversions (read - iolock - page fault - page_mkwrite
- iolock) and so we cannot use an IO path lock to serialise page
write faults against truncate operations.
Instead, introduce a new lock that is used *only* in the
->page_mkwrite path that is the equivalent of the iolock. The lock
ordering in a page fault is i_mmaplock -> page lock -> i_ilock,
and so in truncate we can i_iolock -> i_mmaplock and so lock out
new write faults during the process of truncation.
Because i_mmap_lock is outside the page lock, we can hold it across
all the same operations we hold the i_iolock for. The only
difference is that we never hold the i_mmaplock in the normal IO
path and so do not ever have the possibility that we can page fault
inside it. Hence there are no recursion issues on the i_mmap_lock
and so we can use it to serialise page fault IO against inode
modification operations that affect the IO path.
This patch introduces the i_mmaplock infrastructure, lockdep
annotations and initialisation/destruction code. Use of the new lock
will be in subsequent patches.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
This leads to log recovery throwing errors like:
XFS (md0): Mounting V5 Filesystem
XFS (md0): Starting recovery (logdev: internal)
XFS (md0): Unknown buffer type 0!
XFS (md0): _xfs_buf_ioapply: no ops on block 0xaea8802/0x1
ffff8800ffc53800: 58 41 47 49 .....
Which is the AGI buffer magic number.
Ensure that we set the type appropriately in both unlink list
addition and removal.
cc: <stable@vger.kernel.org> # 3.10 to current
Tested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Adds a new function named xfs_cross_rename(), responsible for
handling requests from sys_renameat2() using RENAME_EXCHANGE flag.
Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
The kernel compile doesn't turn on these checks by default, so it's
only when I do a kernel-user sync that I find that there are lots of
compiler warnings waiting to be fixed. Fix up these set-but-unused
warnings.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
More on-disk format consolidation. A few declarations that weren't on-disk
format related move into better suitable spots.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
There's no need to store a full struct xfs_trans_res on the stack in
xfs_create() and copy the fields. Use a pointer to the appropriate
structures embedded in the xfs_mount.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
xfs_set_diflags() allows it to be set on non-directory inodes, and
this flags errors in xfs_repair. Further, inode allocation allows
the same directory-only flag to be inherited to non-directories.
Make sure directory inode flags don't appear on other types of
inodes.
This fixes several xfstests scratch fileystem corruption reports
(e.g. xfs/050) now that xfstests checks scratch filesystems after
test completion.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
The typedef for timespecs and nanotime() are completely unnecessary,
and delay() can be moved to fs/xfs/linux.h, which means this file
can go away.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
We do some work in xfs_buf_ioend, and some work in
xfs_buf_iodone_work, but much of that functionality is the same.
This work can all be done in a single function, leaving
xfs_buf_iodone just a wrapper to determine if we should execute it
by workqueue or directly. hence rename xfs_buf_iodone_work to
xfs_buf_ioend(), and add a new xfs_buf_ioend_async() for places that
need async processing.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Move the resblks test out of the xfs_dir_canenter,
and into the caller.
This makes a little more sense on the face of it;
xfs_dir_canenter immediately returns if resblks !=0;
and given some of the comments preceding the calls:
* Check for ability to enter directory entry, if no space reserved.
even more so.
It also facilitates the next patch.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Only one user of the macro and the dirty mapping check is redundant
so just get rid of it.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Convert all the errors the core XFs code to negative error signs
like the rest of the kernel and remove all the sign conversion we
do in the interface layers.
Errors for conversion (and comparison) found via searches like:
$ git grep " E" fs/xfs
$ git grep "return E" fs/xfs
$ git grep " E[A-Z].*;$" fs/xfs
Negation points found via searches like:
$ git grep "= -[a-z,A-Z]" fs/xfs
$ git grep "return -[a-z,A-D,F-Z]" fs/xfs
$ git grep " -[a-z].*;" fs/xfs
[ with some bits I missed from Brian Foster ]
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
XFS_ERROR was designed long ago to trap return values, but it's not
runtime configurable, it's not consistently used, and we can do
similar error trapping with ftrace scripts and triggers from
userspace.
Just nuke XFS_ERROR and associated bits.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
mkfs has turned on the XFS_SB_VERSION_NLINKBIT feature bit by
default since November 2007. It's about time we simply made the
kernel code turn it on by default and so always convert v1 inodes to
v2 inodes when reading them in from disk or allocating them. This
This removes needless version checks and modification when bumping
link counts on inodes, and will take code out of a few common code
paths.
text data bss dec hex filename
783251 100867 616 884734 d7ffe fs/xfs/xfs.o.orig
782664 100867 616 884147 d7db3 fs/xfs/xfs.o.patched
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Create the xfs_calc_finobt_res() helper to calculate the finobt log
reservation for inode allocation and free. Update
XFS_IALLOC_SPACE_RES() to reserve blocks for the additional finobt
insertion on inode allocation. Create XFS_IFREE_SPACE_RES() to
reserve blocks for the potential finobt record insertion on inode
free (i.e., if an inode chunk was previously fully allocated).
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
There is no good reason to create a filestream when a directory entry
is created. Delay it until the first allocation happens to simply
the code and reduce the amount of mru cache lookups we do.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
In Linux we will always be able to find a parent inode for file that are
undergoing I/O. Use this to simply the file stream allocator by only
keeping track of parent inodes.
Signed-off-by: Christoph Hellwig <hch@lst.de>
We never test the flag except in xfs_inode_is_filestream, but that
function already tests the on-disk flag or filesystem wide flags,
and is used to decide if we want to set XFS_IFILESTREAM in the
first place.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
xfstests generic/004 reproduces an ilock deadlock using the tmpfile
interface when selinux is enabled. This occurs because
xfs_create_tmpfile() takes the ilock and then calls d_tmpfile(). The
latter eventually calls into xfs_xattr_get() which attempts to get the
lock again. E.g.:
xfs_io D ffffffff81c134c0 4096 3561 3560 0x00000080
ffff8801176a1a68 0000000000000046 ffff8800b401b540 ffff8801176a1fd8
00000000001d5800 00000000001d5800 ffff8800b401b540 ffff8800b401b540
ffff8800b73a6bd0 fffffffeffffffff ffff8800b73a6bd8 ffff8800b5ddb480
Call Trace:
[<ffffffff8177f969>] schedule+0x29/0x70
[<ffffffff81783a65>] rwsem_down_read_failed+0xc5/0x120
[<ffffffffa05aa97f>] ? xfs_ilock_attr_map_shared+0x1f/0x50 [xfs]
[<ffffffff813b3434>] call_rwsem_down_read_failed+0x14/0x30
[<ffffffff810ed179>] ? down_read_nested+0x89/0xa0
[<ffffffffa05aa7f2>] ? xfs_ilock+0x122/0x250 [xfs]
[<ffffffffa05aa7f2>] xfs_ilock+0x122/0x250 [xfs]
[<ffffffffa05aa97f>] xfs_ilock_attr_map_shared+0x1f/0x50 [xfs]
[<ffffffffa05701d0>] xfs_attr_get+0x90/0xe0 [xfs]
[<ffffffffa0565e07>] xfs_xattr_get+0x37/0x50 [xfs]
[<ffffffff8124842f>] generic_getxattr+0x4f/0x70
[<ffffffff8133fd9e>] inode_doinit_with_dentry+0x1ae/0x650
[<ffffffff81340e0c>] selinux_d_instantiate+0x1c/0x20
[<ffffffff813351bb>] security_d_instantiate+0x1b/0x30
[<ffffffff81237db0>] d_instantiate+0x50/0x70
[<ffffffff81237e85>] d_tmpfile+0xb5/0xc0
[<ffffffffa05add02>] xfs_create_tmpfile+0x362/0x410 [xfs]
[<ffffffffa0559ac8>] xfs_vn_tmpfile+0x18/0x20 [xfs]
[<ffffffff81230388>] path_openat+0x228/0x6a0
[<ffffffff810230f9>] ? sched_clock+0x9/0x10
[<ffffffff8105a427>] ? kvm_clock_read+0x27/0x40
[<ffffffff8124054f>] ? __alloc_fd+0xaf/0x1f0
[<ffffffff8123101a>] do_filp_open+0x3a/0x90
[<ffffffff817845e7>] ? _raw_spin_unlock+0x27/0x40
[<ffffffff8124054f>] ? __alloc_fd+0xaf/0x1f0
[<ffffffff8121e3ce>] do_sys_open+0x12e/0x210
[<ffffffff8121e4ce>] SyS_open+0x1e/0x20
[<ffffffff8178eda9>] system_call_fastpath+0x16/0x1b
xfs_vn_tmpfile() also fails to initialize security on the newly created
inode.
Pull the d_tmpfile() call up into xfs_vn_tmpfile() after the transaction
has been committed and the inode unlocked. Also, initialize security on
the inode based on the parent directory provided via the tmpfile call.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
A set of fixes which makes sure we are taking the ilock whenever accessing the
extent list. This was associated with "Access to block zero" messages which
may result in extent list corruption.
The VFS allows an anonymous temporary file to be named at a later
time via a linkat() syscall. The inodes for O_TMPFILE files are
are marked with a special flag I_LINKABLE and have a zero link count.
To support this in XFS, xfs_link() detects if this flag I_LINKABLE
is set and behaves appropriately when detected. So in this case,
its transaciton reservation takes into account the additional
overhead of removing the inode from the unlinked list. Then the
inode is removed from the unlinked list and the directory entry
is added. Finally its link count is bumped accordingly.
Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ben Myers <bpm@sgi.com>
Add two functions xfs_create_tmpfile() and xfs_vn_tmpfile()
to support O_TMPFILE file creation.
In contrast to xfs_create(), xfs_create_tmpfile() has a different
log reservation to the regular file creation because there is no
directory modification, and doesn't check if an entry can be added
to the directory, but the reservation quotas is required appropriately,
and finally its inode is added to the unlinked list.
xfs_vn_tmpfile() add one O_TMPFILE method to VFS interface and directly
invoke xfs_create_tmpfile().
Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ben Myers <bpm@sgi.com>
It will be reused by the O_TMPFILE creation function.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
Equivalent to xfs_ilock_data_map_shared, except for the attribute fork.
Make xfs_getbmap use it if called for the attribute fork instead of
xfs_ilock_data_map_shared.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
