Pull btrfs fixes from David Sterba:
- fix memory leak in qgroup relation ioctl when qgroup levels are
invalid
- don't write back dirty metadata on filesystem with errors
- properly log renamed links
- properly mark prealloc extent range beyond inode size as dirty (when
no-noles is not enabled)
* tag 'for-6.18-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: mark dirty extent range for out of bound prealloc extents
btrfs: set inode flag BTRFS_INODE_COPY_EVERYTHING when logging new name
btrfs: fix memory leak of qgroup_list in btrfs_add_qgroup_relation
btrfs: ensure no dirty metadata is written back for an fs with errors
In btrfs_fallocate(), when the allocated range overlaps with a prealloc
extent and the extent starts after i_size, the range doesn't get marked
dirty in file_extent_tree. This results in persisting an incorrect
disk_i_size for the inode when not using the no-holes feature.
This is reproducible since commit 41a2ee75aa ("btrfs: introduce
per-inode file extent tree"), then became hidden since commit 3d7db6e8bd
("btrfs: don't allocate file extent tree for non regular files") and then
visible again after commit 8679d2687c ("btrfs: initialize
inode::file_extent_tree after i_mode has been set"), which fixes the
previous commit.
The following reproducer triggers the problem:
$ cat test.sh
MNT=/mnt/test
DEV=/dev/vdb
mkdir -p $MNT
mkfs.btrfs -f -O ^no-holes $DEV
mount $DEV $MNT
touch $MNT/file1
fallocate -n -o 1M -l 2M $MNT/file1
umount $MNT
mount $DEV $MNT
len=$((1 * 1024 * 1024))
fallocate -o 1M -l $len $MNT/file1
du --bytes $MNT/file1
umount $MNT
mount $DEV $MNT
du --bytes $MNT/file1
umount $MNT
Running the reproducer gives the following result:
$ ./test.sh
(...)
2097152 /mnt/test/file1
1048576 /mnt/test/file1
The difference is exactly 1048576 as we assigned.
Fix by adding a call to btrfs_inode_set_file_extent_range() in
btrfs_fallocate_update_isize().
Fixes: 41a2ee75aa ("btrfs: introduce per-inode file extent tree")
Signed-off-by: austinchang <austinchang@synology.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
If we are logging a new name make sure our inode has the runtime flag
BTRFS_INODE_COPY_EVERYTHING set so that at btrfs_log_inode() we will find
new inode refs/extrefs in the subvolume tree and copy them into the log
tree.
We are currently doing it when adding a new link but we are missing it
when renaming.
An example where this makes a new name not persisted:
1) create symlink with name foo in directory A
2) fsync directory A, which persists the symlink
3) rename the symlink from foo to bar
4) fsync directory A to persist the new symlink name
Step 4 isn't working correctly as it's not logging the new name and also
leaving the old inode ref in the log tree, so after a power failure the
symlink still has the old name of "foo". This is because when we first
fsync directoy A we log the symlink's inode (as it's a new entry) and at
btrfs_log_inode() we set the log mode to LOG_INODE_ALL and then because
we are using that mode and the inode has the runtime flag
BTRFS_INODE_NEEDS_FULL_SYNC set, we clear that flag as well as the flag
BTRFS_INODE_COPY_EVERYTHING. That means the next time we log the inode,
during the rename through the call to btrfs_log_new_name() (calling
btrfs_log_inode_parent() and then btrfs_log_inode()), we will not search
the subvolume tree for new refs/extrefs and jump directory to the
'log_extents' label.
Fix this by making sure we set BTRFS_INODE_COPY_EVERYTHING on an inode
when we are about to log a new name. A test case for fstests will follow
soon.
Reported-by: Vyacheslav Kovalevsky <slava.kovalevskiy.2014@gmail.com>
Link: https://lore.kernel.org/linux-btrfs/ac949c74-90c2-4b9a-b7fd-1ffc5c3175c7@gmail.com/
Reviewed-by: Boris Burkov <boris@bur.io>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When btrfs_add_qgroup_relation() is called with invalid qgroup levels
(src >= dst), the function returns -EINVAL directly without freeing the
preallocated qgroup_list structure passed by the caller. This causes a
memory leak because the caller unconditionally sets the pointer to NULL
after the call, preventing any cleanup.
The issue occurs because the level validation check happens before the
mutex is acquired and before any error handling path that would free
the prealloc pointer. On this early return, the cleanup code at the
'out' label (which includes kfree(prealloc)) is never reached.
In btrfs_ioctl_qgroup_assign(), the code pattern is:
prealloc = kzalloc(sizeof(*prealloc), GFP_KERNEL);
ret = btrfs_add_qgroup_relation(trans, sa->src, sa->dst, prealloc);
prealloc = NULL; // Always set to NULL regardless of return value
...
kfree(prealloc); // This becomes kfree(NULL), does nothing
When the level check fails, 'prealloc' is never freed by either the
callee or the caller, resulting in a 64-byte memory leak per failed
operation. This can be triggered repeatedly by an unprivileged user
with access to a writable btrfs mount, potentially exhausting kernel
memory.
Fix this by freeing prealloc before the early return, ensuring prealloc
is always freed on all error paths.
Fixes: 4addc1ffd6 ("btrfs: qgroup: preallocate memory before adding a relation")
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Shardul Bankar <shardulsb08@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
During development of a minor feature (make sure all btrfs_bio::end_io()
is called in task context), I noticed a crash in generic/388, where
metadata writes triggered new works after btrfs_stop_all_workers().
It turns out that it can even happen without any code modification, just
using RAID5 for metadata and the same workload from generic/388 is going
to trigger the use-after-free.
[CAUSE]
If btrfs hits an error, the fs is marked as error, no new
transaction is allowed thus metadata is in a frozen state.
But there are some metadata modifications before that error, and they are
still in the btree inode page cache.
Since there will be no real transaction commit, all those dirty folios
are just kept as is in the page cache, and they can not be invalidated
by invalidate_inode_pages2() call inside close_ctree(), because they are
dirty.
And finally after btrfs_stop_all_workers(), we call iput() on btree
inode, which triggers writeback of those dirty metadata.
And if the fs is using RAID56 metadata, this will trigger RMW and queue
new works into rmw_workers, which is already stopped, causing warning
from queue_work() and use-after-free.
[FIX]
Add a special handling for write_one_eb(), that if the fs is already in
an error state, immediately mark the bbio as failure, instead of really
submitting them.
Then during close_ctree(), iput() will just discard all those dirty
tree blocks without really writing them back, thus no more new jobs for
already stopped-and-freed workqueues.
The extra discard in write_one_eb() also acts as an extra safenet.
E.g. the transaction abort is triggered by some extent/free space
tree corruptions, and since extent/free space tree is already corrupted
some tree blocks may be allocated where they shouldn't be (overwriting
existing tree blocks). In that case writing them back will further
corrupting the fs.
CC: stable@vger.kernel.org # 6.6+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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