free_device rcu callback, scheduled from btrfs_rm_dev_replace_srcdev,
can be processed before btrfs_scratch_superblock is called, which would
result in a use-after-free on btrfs_device contents. Fix this by
zeroing the superblock before the rcu callback is registered.
Cc: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
The current implementation of worker threads in Btrfs has races in
worker stopping code, which cause all kinds of panics and lockups when
running btrfs/011 xfstest in a loop. The problem is that
btrfs_stop_workers is unsynchronized with respect to check_idle_worker,
check_busy_worker and __btrfs_start_workers.
E.g., check_idle_worker race flow:
btrfs_stop_workers(): check_idle_worker(aworker):
- grabs the lock
- splices the idle list into the
working list
- removes the first worker from the
working list
- releases the lock to wait for
its kthread's completion
- grabs the lock
- if aworker is on the working list,
moves aworker from the working list
to the idle list
- releases the lock
- grabs the lock
- puts the worker
- removes the second worker from the
working list
......
btrfs_stop_workers returns, aworker is on the idle list
FS is umounted, memory is freed
......
aworker is waken up, fireworks ensue
With this applied, I wasn't able to trigger the problem in 48 hours,
whereas previously I could reliably reproduce at least one of these
races within an hour.
Reported-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
The crash[1] is found by xfstests/generic/208 with "-o compress",
it's not reproduced everytime, but it does panic.
The bug is quite interesting, it's actually introduced by a recent commit
(573aecafca,
Btrfs: actually limit the size of delalloc range).
Btrfs implements delay allocation, so during writeback, we
(1) get a page A and lock it
(2) search the state tree for delalloc bytes and lock all pages within the range
(3) process the delalloc range, including find disk space and create
ordered extent and so on.
(4) submit the page A.
It runs well in normal cases, but if we're in a racy case, eg.
buffered compressed writes and aio-dio writes,
sometimes we may fail to lock all pages in the 'delalloc' range,
in which case, we need to fall back to search the state tree again with
a smaller range limit(max_bytes = PAGE_CACHE_SIZE - offset).
The mentioned commit has a side effect, that is, in the fallback case,
we can find delalloc bytes before the index of the page we already have locked,
so we're in the case of (delalloc_end <= *start) and return with (found > 0).
This ends with not locking delalloc pages but making ->writepage still
process them, and the crash happens.
This fixes it by just thinking that we find nothing and returning to caller
as the caller knows how to deal with it properly.
[1]:
------------[ cut here ]------------
kernel BUG at mm/page-writeback.c:2170!
[...]
CPU: 2 PID: 11755 Comm: btrfs-delalloc- Tainted: G O 3.11.0+ #8
[...]
RIP: 0010:[<ffffffff810f5093>] [<ffffffff810f5093>] clear_page_dirty_for_io+0x1e/0x83
[...]
[ 4934.248731] Stack:
[ 4934.248731] ffff8801477e5dc8 ffffea00049b9f00 ffff8801869f9ce8 ffffffffa02b841a
[ 4934.248731] 0000000000000000 0000000000000000 0000000000000fff 0000000000000620
[ 4934.248731] ffff88018db59c78 ffffea0005da8d40 ffffffffa02ff860 00000001810016c0
[ 4934.248731] Call Trace:
[ 4934.248731] [<ffffffffa02b841a>] extent_range_clear_dirty_for_io+0xcf/0xf5 [btrfs]
[ 4934.248731] [<ffffffffa02a8889>] compress_file_range+0x1dc/0x4cb [btrfs]
[ 4934.248731] [<ffffffff8104f7af>] ? detach_if_pending+0x22/0x4b
[ 4934.248731] [<ffffffffa02a8bad>] async_cow_start+0x35/0x53 [btrfs]
[ 4934.248731] [<ffffffffa02c694b>] worker_loop+0x14b/0x48c [btrfs]
[ 4934.248731] [<ffffffffa02c6800>] ? btrfs_queue_worker+0x25c/0x25c [btrfs]
[ 4934.248731] [<ffffffff810608f5>] kthread+0x8d/0x95
[ 4934.248731] [<ffffffff81060868>] ? kthread_freezable_should_stop+0x43/0x43
[ 4934.248731] [<ffffffff814fe09c>] ret_from_fork+0x7c/0xb0
[ 4934.248731] [<ffffffff81060868>] ? kthread_freezable_should_stop+0x43/0x43
[ 4934.248731] Code: ff 85 c0 0f 94 c0 0f b6 c0 59 5b 5d c3 0f 1f 44 00 00 55 48 89 e5 41 54 53 48 89 fb e8 2c de 00 00 49 89 c4 48 8b 03 a8 01 75 02 <0f> 0b 4d 85 e4 74 52 49 8b 84 24 80 00 00 00 f6 40 20 01 75 44
[ 4934.248731] RIP [<ffffffff810f5093>] clear_page_dirty_for_io+0x1e/0x83
[ 4934.248731] RSP <ffff8801869f9c48>
[ 4934.280307] ---[ end trace 36f06d3f8750236a ]---
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
If we crash with a log, remount and recover that log, and then crash before we
can commit another transaction we will get transid verify errors on the next
mount. This is because we were not zero'ing out the log when we committed the
transaction after recovery. This is ok as long as we commit another transaction
at some point in the future, but if you abort or something else goes wrong you
can end up in this weird state because the recovery stuff says that the tree log
should have a generation+1 of the super generation, which won't be the case of
the transaction that was started for recovery. Fix this by removing the check
and _always_ zero out the log portion of the super when we commit a transaction.
This fixes the transid verify issues I was seeing with my force errors tests.
Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Pull btrfs fixes from Chris Mason:
"These are mostly bug fixes and a two small performance fixes. The
most important of the bunch are Josef's fix for a snapshotting
regression and Mark's update to fix compile problems on arm"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: (25 commits)
Btrfs: create the uuid tree on remount rw
btrfs: change extent-same to copy entire argument struct
Btrfs: dir_inode_operations should use btrfs_update_time also
btrfs: Add btrfs: prefix to kernel log output
btrfs: refuse to remount read-write after abort
Btrfs: btrfs_ioctl_default_subvol: Revert back to toplevel subvolume when arg is 0
Btrfs: don't leak transaction in btrfs_sync_file()
Btrfs: add the missing mutex unlock in write_all_supers()
Btrfs: iput inode on allocation failure
Btrfs: remove space_info->reservation_progress
Btrfs: kill delay_iput arg to the wait_ordered functions
Btrfs: fix worst case calculator for space usage
Revert "Btrfs: rework the overcommit logic to be based on the total size"
Btrfs: improve replacing nocow extents
Btrfs: drop dir i_size when adding new names on replay
Btrfs: replay dir_index items before other items
Btrfs: check roots last log commit when checking if an inode has been logged
Btrfs: actually log directory we are fsync()'ing
Btrfs: actually limit the size of delalloc range
Btrfs: allocate the free space by the existed max extent size when ENOSPC
...
Users have been complaining of the uuid tree stuff warning that there is no uuid
root when trying to do snapshot operations. This is because if you mount -o ro
we will not create the uuid tree. But then if you mount -o rw,remount we will
still not create it and then any subsequent snapshot/subvol operations you try
to do will fail gloriously. Fix this by creating the uuid_root on remount rw if
it was not already there. Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
btrfs_ioctl_file_extent_same() uses __put_user_unaligned() to copy some data
back to it's argument struct. Unfortunately, not all architectures provide
__put_user_unaligned(), so compiles break on them if btrfs is selected.
Instead, just copy the whole struct in / out at the start and end of
operations, respectively.
Signed-off-by: Mark Fasheh <mfasheh@suse.de>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Commit 2bc5565286 (Btrfs: don't update atime on
RO subvolumes) ensures that the access time of an inode is not updated when
the inode lives in a read-only subvolume.
However, if a directory on a read-only subvolume is accessed, the atime is
updated. This results in a write operation to a read-only subvolume. I
believe that access times should never be updated on read-only subvolumes.
To reproduce:
# mkfs.btrfs -f /dev/dm-3
(...)
# mount /dev/dm-3 /mnt
# btrfs subvol create /mnt/sub
Create subvolume '/mnt/sub'
# mkdir /mnt/sub/dir
# echo "abc" > /mnt/sub/dir/file
# btrfs subvol snapshot -r /mnt/sub /mnt/rosnap
Create a readonly snapshot of '/mnt/sub' in '/mnt/rosnap'
# stat /mnt/rosnap/dir
File: `/mnt/rosnap/dir'
Size: 8 Blocks: 0 IO Block: 4096 directory
Device: 16h/22d Inode: 257 Links: 1
Access: (0755/drwxr-xr-x) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2013-09-11 07:21:49.389157126 -0400
Modify: 2013-09-11 07:22:02.330156079 -0400
Change: 2013-09-11 07:22:02.330156079 -0400
# ls /mnt/rosnap/dir
file
# stat /mnt/rosnap/dir
File: `/mnt/rosnap/dir'
Size: 8 Blocks: 0 IO Block: 4096 directory
Device: 16h/22d Inode: 257 Links: 1
Access: (0755/drwxr-xr-x) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2013-09-11 07:22:56.797151670 -0400
Modify: 2013-09-11 07:22:02.330156079 -0400
Change: 2013-09-11 07:22:02.330156079 -0400
Reported-by: Koen De Wit <koen.de.wit@oracle.com>
Signed-off-by: Guangyu Sun <guangyu.sun@oracle.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
The kernel log entries for device label %s and device fsid %pU
are missing the btrfs: prefix. Add those here.
Signed-off-by: Frank Holton <fholton@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
It's still possible to flip the filesystem into RW mode after it's
remounted RO due to an abort. There are lots of places that check for
the superblock error bit and will not write data, but we should not let
the filesystem appear read-write.
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
In btrfs_sync_file(), if the call to btrfs_log_dentry_safe() returns
a negative error (for e.g. -ENOMEM via btrfs_log_inode()), we would
return without ending/freeing the transaction.
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
The BUG() was replaced by btrfs_error() and return -EIO with the
patch "get rid of one BUG() in write_all_supers()", but the missing
mutex_unlock() was overlooked.
The 0-DAY kernel build service from Intel reported the missing
unlock which was found by the coccinelle tool:
fs/btrfs/disk-io.c:3422:2-8: preceding lock on line 3374
Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
We don't do the iput when we fail to allocate our delayed delalloc work in
__start_delalloc_inodes, fix this.
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
This is a left over of how we used to wait for ordered extents, which was to
grab the inode and then run filemap flush on it. However if we have an ordered
extent then we already are holding a ref on the inode, and we just use
btrfs_start_ordered_extent anyway, so there is no reason to have an extra ref on
the inode to start work on the ordered extent. Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Forever ago I made the worst case calculator say that we could potentially split
into 3 blocks for every level on the way down, which isn't right. If we split
we're only going to get two new blocks, the one we originally cow'ed and the new
one we're going to split. Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
This reverts commit 70afa3998c. It is causing
performance issues and wasn't actually correct. There were problems with the
way we flushed delalloc and that was the real cause of the early enospc.
Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Various people have hit a deadlock when running btrfs/011. This is because when
replacing nocow extents we will take the i_mutex to make sure nobody messes with
the file while we are replacing the extent. The problem is we are already
holding a transaction open, which is a locking inversion, so instead we need to
save these inodes we find and then process them outside of the transaction.
Further we can't just lock the inode and assume we are good to go. We need to
lock the extent range and then read back the extent cache for the inode to make
sure the extent really still points at the physical block we want. If it
doesn't we don't have to copy it. Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
So if we have dir_index items in the log that means we also have the inode item
as well, which means that the inode's i_size is correct. However when we
process dir_index'es we call btrfs_add_link() which will increase the
directory's i_size for the new entry. To fix this we need to just set the dir
items i_size to 0, and then as we find dir_index items we adjust the i_size.
btrfs_add_link() will do it for new entries, and if the entry already exists we
can just add the name_len to the i_size ourselves. Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
A user reported a bug where his log would not replay because he was getting
-EEXIST back. This was because he had a file moved into a directory that was
logged. What happens is the file had a lower inode number, and so it is
processed first when replaying the log, and so we add the inode ref in for the
directory it was moved to. But then we process the directories DIR_INDEX item
and try to add the inode ref for that inode and it fails because we already
added it when we replayed the inode. To solve this problem we need to just
process any DIR_INDEX items we have in the log first so this all is taken care
of, and then we can replay the rest of the items. With this patch my reproducer
can remount the file system properly instead of erroring out. Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Liu introduced a local copy of the last log commit for an inode to make sure we
actually log an inode even if a log commit has already taken place. In order to
make sure we didn't relog the same inode multiple times he set this local copy
to the current trans when we log the inode, because usually we log the inode and
then sync the log. The exception to this is during rename, we will relog an
inode if the name changed and it is already in the log. The problem with this
is then we go to sync the inode, and our check to see if the inode has already
been logged is tripped and we don't sync the log. To fix this we need to _also_
check against the roots last log commit, because it could be less than what is
in our local copy of the log commit. This fixes a bug where we rename a file
into a directory and then fsync the directory and then on remount the directory
is no longer there. Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
If you just create a directory and then fsync that directory and then pull the
power plug you will come back up and the directory will not be there. That is
because we won't actually create directories if we've logged files inside of
them since they will be created on replay, but in this check we will set our
logged_trans of our current directory if it happens to be a directory, making us
think it doesn't need to be logged. Fix the logic to only do this to parent
directories. Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Darrick J. Wong
Chris Mason
Ilya Dryomov
Liu Bo
Josef Bacik
Linus Torvalds
Mark Fasheh
Guangyu Sun
Frank Holton
David Sterba
chandan
Filipe David Borba Manana
Stefan Behrens