With the conversion of the tree locks to rwsem I got the following
lockdep splat:
======================================================
WARNING: possible circular locking dependency detected
5.8.0-rc7-00165-g04ec4da5f45f-dirty #922 Not tainted
------------------------------------------------------
compsize/11122 is trying to acquire lock:
ffff889fabca8768 (&mm->mmap_lock#2){++++}-{3:3}, at: __might_fault+0x3e/0x90
but task is already holding lock:
ffff889fe720fe40 (btrfs-fs-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x39/0x180
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (btrfs-fs-00){++++}-{3:3}:
down_write_nested+0x3b/0x70
__btrfs_tree_lock+0x24/0x120
btrfs_search_slot+0x756/0x990
btrfs_lookup_inode+0x3a/0xb4
__btrfs_update_delayed_inode+0x93/0x270
btrfs_async_run_delayed_root+0x168/0x230
btrfs_work_helper+0xd4/0x570
process_one_work+0x2ad/0x5f0
worker_thread+0x3a/0x3d0
kthread+0x133/0x150
ret_from_fork+0x1f/0x30
-> #1 (&delayed_node->mutex){+.+.}-{3:3}:
__mutex_lock+0x9f/0x930
btrfs_delayed_update_inode+0x50/0x440
btrfs_update_inode+0x8a/0xf0
btrfs_dirty_inode+0x5b/0xd0
touch_atime+0xa1/0xd0
btrfs_file_mmap+0x3f/0x60
mmap_region+0x3a4/0x640
do_mmap+0x376/0x580
vm_mmap_pgoff+0xd5/0x120
ksys_mmap_pgoff+0x193/0x230
do_syscall_64+0x50/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xa9
-> #0 (&mm->mmap_lock#2){++++}-{3:3}:
__lock_acquire+0x1272/0x2310
lock_acquire+0x9e/0x360
__might_fault+0x68/0x90
_copy_to_user+0x1e/0x80
copy_to_sk.isra.32+0x121/0x300
search_ioctl+0x106/0x200
btrfs_ioctl_tree_search_v2+0x7b/0xf0
btrfs_ioctl+0x106f/0x30a0
ksys_ioctl+0x83/0xc0
__x64_sys_ioctl+0x16/0x20
do_syscall_64+0x50/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xa9
other info that might help us debug this:
Chain exists of:
&mm->mmap_lock#2 --> &delayed_node->mutex --> btrfs-fs-00
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(btrfs-fs-00);
lock(&delayed_node->mutex);
lock(btrfs-fs-00);
lock(&mm->mmap_lock#2);
*** DEADLOCK ***
1 lock held by compsize/11122:
#0: ffff889fe720fe40 (btrfs-fs-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x39/0x180
stack backtrace:
CPU: 17 PID: 11122 Comm: compsize Kdump: loaded Not tainted 5.8.0-rc7-00165-g04ec4da5f45f-dirty #922
Hardware name: Quanta Tioga Pass Single Side 01-0030993006/Tioga Pass Single Side, BIOS F08_3A18 12/20/2018
Call Trace:
dump_stack+0x78/0xa0
check_noncircular+0x165/0x180
__lock_acquire+0x1272/0x2310
lock_acquire+0x9e/0x360
? __might_fault+0x3e/0x90
? find_held_lock+0x72/0x90
__might_fault+0x68/0x90
? __might_fault+0x3e/0x90
_copy_to_user+0x1e/0x80
copy_to_sk.isra.32+0x121/0x300
? btrfs_search_forward+0x2a6/0x360
search_ioctl+0x106/0x200
btrfs_ioctl_tree_search_v2+0x7b/0xf0
btrfs_ioctl+0x106f/0x30a0
? __do_sys_newfstat+0x5a/0x70
? ksys_ioctl+0x83/0xc0
ksys_ioctl+0x83/0xc0
__x64_sys_ioctl+0x16/0x20
do_syscall_64+0x50/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xa9
The problem is we're doing a copy_to_user() while holding tree locks,
which can deadlock if we have to do a page fault for the copy_to_user().
This exists even without my locking changes, so it needs to be fixed.
Rework the search ioctl to do the pre-fault and then
copy_to_user_nofault for the copying.
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
User Forza reported on IRC that some invalid combinations of file
attributes are accepted by chattr.
The NODATACOW and compression file flags/attributes are mutually
exclusive, but they could be set by 'chattr +c +C' on an empty file. The
nodatacow will be in effect because it's checked first in
btrfs_run_delalloc_range.
Extend the flag validation to catch the following cases:
- input flags are conflicting
- old and new flags are conflicting
- initialize the local variable with inode flags after inode ls locked
Inode attributes take precedence over mount options and are an
independent setting.
Nocompress would be a no-op with nodatacow, but we don't want to mix
any compression-related options with nodatacow.
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: David Sterba <dsterba@suse.com>
Add retrieval of the filesystem's metadata UUID to the fsinfo ioctl.
This is driven by setting the BTRFS_FS_INFO_FLAG_METADATA_UUID flag in
btrfs_ioctl_fs_info_args::flags.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Add retrieval of the filesystem's generation to the fsinfo ioctl. This is
driven by setting the BTRFS_FS_INFO_FLAG_GENERATION flag in
btrfs_ioctl_fs_info_args::flags.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
With the recent addition of filesystem checksum types other than CRC32c,
it is not anymore hard-coded which checksum type a btrfs filesystem uses.
Up to now there is no good way to read the filesystem checksum, apart from
reading the filesystem UUID and then query sysfs for the checksum type.
Add a new csum_type and csum_size fields to the BTRFS_IOC_FS_INFO ioctl
command which usually is used to query filesystem features. Also add a
flags member indicating that the kernel responded with a set csum_type and
csum_size field.
For compatibility reasons, only return the csum_type and csum_size if
the BTRFS_FS_INFO_FLAG_CSUM_INFO flag was passed to the kernel. Also
clear any unknown flags so we don't pass false positives to user-space
newer than the kernel.
To simplify further additions to the ioctl, also switch the padding to a
u8 array. Pahole was used to verify the result of this switch:
The csum members are added before flags, which might look odd, but this
is to keep the alignment requirements and not to introduce holes in the
structure.
$ pahole -C btrfs_ioctl_fs_info_args fs/btrfs/btrfs.ko
struct btrfs_ioctl_fs_info_args {
__u64 max_id; /* 0 8 */
__u64 num_devices; /* 8 8 */
__u8 fsid[16]; /* 16 16 */
__u32 nodesize; /* 32 4 */
__u32 sectorsize; /* 36 4 */
__u32 clone_alignment; /* 40 4 */
__u16 csum_type; /* 44 2 */
__u16 csum_size; /* 46 2 */
__u64 flags; /* 48 8 */
__u8 reserved[968]; /* 56 968 */
/* size: 1024, cachelines: 16, members: 10 */
};
Fixes: 3951e7f050 ("btrfs: add xxhash64 to checksumming algorithms")
Fixes: 3831bf0094 ("btrfs: add sha256 to checksumming algorithm")
CC: stable@vger.kernel.org # 5.5+
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
When the anonymous block device pool is exhausted, subvolume/snapshot
creation fails with EMFILE (Too many files open). This has been reported
by a user. The allocation happens in the second phase during transaction
commit where it's only way out is to abort the transaction
BTRFS: Transaction aborted (error -24)
WARNING: CPU: 17 PID: 17041 at fs/btrfs/transaction.c:1576 create_pending_snapshot+0xbc4/0xd10 [btrfs]
RIP: 0010:create_pending_snapshot+0xbc4/0xd10 [btrfs]
Call Trace:
create_pending_snapshots+0x82/0xa0 [btrfs]
btrfs_commit_transaction+0x275/0x8c0 [btrfs]
btrfs_mksubvol+0x4b9/0x500 [btrfs]
btrfs_ioctl_snap_create_transid+0x174/0x180 [btrfs]
btrfs_ioctl_snap_create_v2+0x11c/0x180 [btrfs]
btrfs_ioctl+0x11a4/0x2da0 [btrfs]
do_vfs_ioctl+0xa9/0x640
ksys_ioctl+0x67/0x90
__x64_sys_ioctl+0x1a/0x20
do_syscall_64+0x5a/0x110
entry_SYSCALL_64_after_hwframe+0x44/0xa9
---[ end trace 33f2f83f3d5250e9 ]---
BTRFS: error (device sda1) in create_pending_snapshot:1576: errno=-24 unknown
BTRFS info (device sda1): forced readonly
BTRFS warning (device sda1): Skipping commit of aborted transaction.
BTRFS: error (device sda1) in cleanup_transaction:1831: errno=-24 unknown
[CAUSE]
When the global anonymous block device pool is exhausted, the following
call chain will fail, and lead to transaction abort:
btrfs_ioctl_snap_create_v2()
|- btrfs_ioctl_snap_create_transid()
|- btrfs_mksubvol()
|- btrfs_commit_transaction()
|- create_pending_snapshot()
|- btrfs_get_fs_root()
|- btrfs_init_fs_root()
|- get_anon_bdev()
[FIX]
Although we can't enlarge the anonymous block device pool, at least we
can preallocate anon_dev for subvolume/snapshot in the first phase,
outside of transaction context and exactly at the moment the user calls
the creation ioctl.
Reported-by: Greed Rong <greedrong@gmail.com>
Link: https://lore.kernel.org/linux-btrfs/CA+UqX+NTrZ6boGnWHhSeZmEY5J76CTqmYjO2S+=tHJX7nb9DPw@mail.gmail.com/
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
All of its children take btrfs_inode so bubble up this requirement to
btrfs_delalloc_reserve_space's interface and stop calling BTRFS_I
internally.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
It needs btrfs_inode so take it as a parameter directly.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
It doesn't use the generic vfs inode for anything use btrfs_inode
directly.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In btrfs_ioctl_get_subvol_info(), there is a classic case where kzalloc()
was incorrectly paired with kzfree(). According to David Sterba, there
isn't any sensitive information in the subvol_info that needs to be
cleared before freeing. So kzfree() isn't really needed, use kfree()
instead.
Signed-off-by: Waiman Long <longman@redhat.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The inode lookup starting at btrfs_iget takes the full location key,
while only the objectid is used to match the inode, because the lookup
happens inside the given root thus the inode number is unique.
The entire location key is properly set up in btrfs_init_locked_inode.
Simplify the helpers and pass only inode number, renaming it to 'ino'
instead of 'objectid'. This allows to remove temporary variables key,
saving some stack space.
Signed-off-by: David Sterba <dsterba@suse.com>
The main function to lookup a root by its id btrfs_get_fs_root takes the
whole key, while only using the objectid. The value of offset is preset
to (u64)-1 but not actually used until btrfs_find_root that does the
actual search.
Switch btrfs_get_fs_root to use only objectid and remove all local
variables that existed just for the lookup. The actual key for search is
set up in btrfs_get_fs_root, reusing another key variable.
Signed-off-by: David Sterba <dsterba@suse.com>
When creating a snapshot, ordered extents need to be flushed and this
can take a long time.
In create_snapshot there are two locks held when this happens:
1. Destination directory inode lock
2. Global subvolume semaphore
This will unnecessarily block other operations like subvolume destroy,
create, or setflag until the snapshot is created.
We can fix that by moving the flush outside the locked section as this
does not depend on the aforementioned locks. The code factors out the
snapshot related work from create_snapshot to btrfs_mksnapshot.
__btrfs_ioctl_snap_create
btrfs_mksubvol
create_subvol
btrfs_mksnapshot
<flush>
btrfs_mksubvol
create_snapshot
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Robbie Ko <robbieko@synology.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The name BTRFS_ROOT_REF_COWS is not very clear about the meaning.
In fact, that bit can only be set to those trees:
- Subvolume roots
- Data reloc root
- Reloc roots for above roots
All other trees won't get this bit set. So just by the result, it is
obvious that, roots with this bit set can have tree blocks shared with
other trees. Either shared by snapshots, or by reloc roots (an special
snapshot created by relocation).
This patch will rename BTRFS_ROOT_REF_COWS to BTRFS_ROOT_SHAREABLE to
make it easier to understand, and update all comment mentioning
"reference counted" to follow the rename.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
With BTRFS_SUBVOL_CREATE_ASYNC support remove it's no longer required to
pass the async_transid parameter so remove it and any code using it.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_ioctl_snap_create_transid no longer takes a transid argument, so
remove it and rename the function to __btrfs_ioctl_snap_create to
reflect it's an internal, worker function.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This functionality was deprecated in kernel 5.4. Since no one has
complained of the impending removal it's time we did so.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add comment ]
Signed-off-by: David Sterba <dsterba@suse.com>
The reflink code is quite large and has been living in ioctl.c since ever.
It has grown over the years after many bug fixes and improvements, and
since I'm planning on making some further improvements on it, it's time
to get it better organized by moving into its own file, reflink.c
(similar to what xfs does for example).
This change only moves the code out of ioctl.c into the new file, it
doesn't do any other change.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There are new types and helpers that are supposed to be used in new code.
As a preparation to get rid of legacy types and API functions do
the conversion here.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There is no point to inform the user about size change if there's none.
Update the message to conform to a commonly used format where the path
and devid are printed and also print old and new sizes.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Marcos Paulo de Souza <marcos@mpdesouza.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ enhance message ]
Signed-off-by: David Sterba <dsterba@suse.com>
This patch removes all haphazard code implementing nocow writers
exclusion from pending snapshot creation and switches to using the drew
lock to ensure this invariant still holds.
'Readers' are snapshot creators from create_snapshot and 'writers' are
nocow writers from buffered write path or btrfs_setsize. This locking
scheme allows for multiple snapshots to happen while any nocow writers
are blocked, since writes to page cache in the nocow path will make
snapshots inconsistent.
So for performance reasons we'd like to have the ability to run multiple
concurrent snapshots and also favors readers in this case. And in case
there aren't pending snapshots (which will be the majority of the cases)
we rely on the percpu's writers counter to avoid cacheline contention.
The main gain from using the drew lock is it's now a lot easier to
reason about the guarantees of the locking scheme and whether there is
some silent breakage lurking.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This ioctl will be responsible for deleting a subvolume using its id.
This can be used when a system has a file system mounted from a
subvolume, rather than the root file system, like below:
/
@subvol1/
@subvol2/
@subvol_default/
If only @subvol_default is mounted, we have no path to reach @subvol1
and @subvol2, thus no way to delete them. Current subvolume delete ioctl
takes a file handle point as argument, and if @subvol_default is
mounted, we can't reach @subvol1 and @subvol2 from the same mount point.
This patch introduces a new ioctl BTRFS_IOC_SNAP_DESTROY_V2 that takes
the extended structure with flags to allow to delete subvolume using
subvolid.
Now, we can use this new ioctl specifying the subvolume id and refer to
the same mount point. It doesn't matter which subvolume was mounted,
since we can reach to the desired one using the subvolume id, and then
delete it.
The full path to the subvolume id is resolved internally and access is
verified as if the subvolume was accessed by path.
The volume args v2 structure is extended to use the existing union for
subvolume id specification, that's valid in case the
BTRFS_SUBVOL_SPEC_BY_ID is set.
Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ update changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
When the device remove v2 ioctl was added, the full support mask was
added to sanity check the flags. However this would allow to let the
subvolume related flags to be accepted. This is not supposed to happen.
Use the correct support mask, which means that now any of
BTRFS_SUBVOL_CREATE_ASYNC, BTRFS_SUBVOL_RDONLY or
BTRFS_SUBVOL_QGROUP_INHERIT will be rejected as ENOTSUPP. Though this is
a user-visible change, specifying subvolume flags for device deletion
does not make sense and there are hopefully no applications doing that.
Reviewed-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Using the defined mask instead of flag enumeration in the ioctl handler
is preferred. No functional changes.
Reviewed-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We are now using these for all roots, rename them to btrfs_put_root()
and btrfs_grab_root();
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that all callers of btrfs_get_fs_root are subsequently calling
btrfs_grab_fs_root and handling dropping the ref when they are done
appropriately, go ahead and push btrfs_grab_fs_root up into
btrfs_get_fs_root.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We create the snapshot and then use it for a bunch of things, we need to
hold a ref on it while we're messing with it.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We look up an arbitrary fs root here, we need to hold a ref on the root
for the duration.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We look up whatever root userspace has given us, we need to hold a ref
throughout this operation. Use 'root' only for the on fs root and not as
a temporary variable elsewhere.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We can wander into a different root, so grab a ref on the root we look
up. Later on we make root = fs_info->tree_root so we need this separate
out label to make sure we do the right cleanup only in the case we're
looking up a different root.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We look up an arbitrary fs root, we need to hold a ref on it while we're
doing our search.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We lookup a arbitrary fs root, we need to hold a ref on that root. If
we're using our own inodes root then grab a ref on that as well to make
the cleanup easier.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We're creating the new root here, but we should hold the ref until after
we've initialized the inode for it.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
All this does is call btrfs_get_fs_root() with check_ref == true. Just
use btrfs_get_fs_root() so we don't have a bunch of different helpers
that do the same thing.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that we have a safe way to update the i_size, replace all uses of
btrfs_ordered_update_i_size with btrfs_inode_safe_disk_i_size_write.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We were using btrfs_i_size_write(), which unconditionally jacks up
inode->disk_i_size. However since clone can operate on ranges we could
have pending ordered extents for a range prior to the start of our clone
operation and thus increase disk_i_size too far and have a hole with no
file extent.
Fix this by using the btrfs_ordered_update_i_size helper which will do
the right thing in the face of pending ordered extents outside of our
clone range.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Merge tag 'fs-dedupe-last-block-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull fs deduplication fix from David Sterba:
"This is a fix for deduplication bug: the last block of two files is
allowed to deduplicated. This got broken in 5.1 by lifting some
generic checks to VFS layer. The affected filesystems are btrfs and
xfs.
The patches are marked for stable as the bug decreases deduplication
effectivity"
* tag 'fs-dedupe-last-block-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
Btrfs: make deduplication with range including the last block work
fs: allow deduplication of eof block into the end of the destination file
Since btrfs was migrated to use the generic VFS helpers for clone and
deduplication, it stopped allowing for the last block of a file to be
deduplicated when the source file size is not sector size aligned (when
eof is somewhere in the middle of the last block). There are two reasons
for that:
1) The generic code always rounds down, to a multiple of the block size,
the range's length for deduplications. This means we end up never
deduplicating the last block when the eof is not block size aligned,
even for the safe case where the destination range's end offset matches
the destination file's size. That rounding down operation is done at
generic_remap_check_len();
2) Because of that, the btrfs specific code does not expect anymore any
non-aligned range length's for deduplication and therefore does not
work if such nona-aligned length is given.
This patch addresses that second part, and it depends on a patch that
fixes generic_remap_check_len(), in the VFS, which was submitted ealier
and has the following subject:
"fs: allow deduplication of eof block into the end of the destination file"
These two patches address reports from users that started seeing lower
deduplication rates due to the last block never being deduplicated when
the file size is not aligned to the filesystem's block size.
Link: https://lore.kernel.org/linux-btrfs/2019-1576167349.500456@svIo.N5dq.dFFD/
CC: stable@vger.kernel.org # 5.1+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We only pass this as 1 from __extent_writepage_io(). The parameter
basically means "pretend I didn't pass in a page". This is silly since
we can simply not pass in the page. Get rid of the parameter from
btrfs_get_extent(), and since it's used as a get_extent_t callback,
remove it from get_extent_t and btree_get_extent(), neither of which
need it.
While we're here, let's document btrfs_get_extent().
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
If scrub returns an error we are not copying back the scrub arguments
structure to user space. This prevents user space to know how much
progress scrub has done if an error happened - this includes -ECANCELED
which is returned when users ask for scrub to stop. A particular use
case, which is used in btrfs-progs, is to resume scrub after it is
canceled, in that case it relies on checking the progress from the scrub
arguments structure and then use that progress in a call to resume
scrub.
So fix this by always copying the scrub arguments structure to user
space, overwriting the value returned to user space with -EFAULT only if
copying the structure failed to let user space know that either that
copying did not happen, and therefore the structure is stale, or it
happened partially and the structure is probably not valid and corrupt
due to the partial copy.
Reported-by: Graham Cobb <g.btrfs@cobb.uk.net>
Link: https://lore.kernel.org/linux-btrfs/d0a97688-78be-08de-ca7d-bcb4c7fb397e@cobb.uk.net/
Fixes: 06fe39ab15 ("Btrfs: do not overwrite scrub error with fault error in scrub ioctl")
CC: stable@vger.kernel.org # 5.1+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Tested-by: Graham Cobb <g.btrfs@cobb.uk.net>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We can just abort the transaction here, and in fact do that for every
other failure in this function except these two cases.
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Normally when cloning a file range if we find an implicit hole at the end
of the range we assume it is because the NO_HOLES feature is enabled.
However that is not always the case. One well known case [1] is when we
have a power failure after mixing buffered and direct IO writes against
the same file.
In such cases we need to punch a hole in the destination file, and if
the NO_HOLES feature is not enabled, we need to insert explicit file
extent items to represent the hole. After commit 690a5dbfc5
("Btrfs: fix ENOSPC errors, leading to transaction aborts, when cloning
extents"), we started to insert file extent items representing the hole
with an item size of 0, which is invalid and should be 53 bytes (the size
of a btrfs_file_extent_item structure), resulting in all sorts of
corruptions and invalid memory accesses. This is detected by the tree
checker when we attempt to write a leaf to disk.
The problem can be sporadically triggered by test case generic/561 from
fstests. That test case does not exercise power failure and creates a new
filesystem when it starts, so it does not use a filesystem created by any
previous test that tests power failure. However the test does both
buffered and direct IO writes (through fsstress) and it's precisely that
which is creating the implicit holes in files. That happens even before
the commit mentioned earlier. I need to investigate why we get those
implicit holes to check if there is a real problem or not. For now this
change fixes the regression of introducing file extent items with an item
size of 0 bytes.
Fix the issue by calling btrfs_punch_hole_range() without passing a
btrfs_clone_extent_info structure, which ensures file extent items are
inserted to represent the hole with a correct item size. We were passing
a btrfs_clone_extent_info with a value of 0 for its 'item_size' field,
which was causing the insertion of file extent items with an item size
of 0.
[1] https://www.spinics.net/lists/linux-btrfs/msg75350.html
Reported-by: David Sterba <dsterba@suse.com>
Fixes: 690a5dbfc5 ("Btrfs: fix ENOSPC errors, leading to transaction aborts, when cloning extents")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The type name is misleading, a single entry is named 'cache' while this
normally means a collection of objects. Rename that everywhere. Also the
identifier was quite long, making function prototypes harder to format.
Suggested-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The on-disk format of block group item makes use of the key that stores
the offset and length. This is further used in the code, although this
makes thing harder to understand. The key is also packed so the
offset/length is not properly aligned as u64.
Add start (key.objectid) and length (key.offset) members to block group
and remove the embedded key. When the item is searched or written, a
local variable for key is used.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
For unknown reasons, the member 'used' in the block group struct is
stored in the b-tree item and accessed everywhere using the special
accessor helper. Let's unify it and make it a regular member and only
update the item before writing it to the tree.
The item is still being used for flags and chunk_objectid, there's some
duplication until the item is removed in following patches.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Some functions are doing some unnecessary indirection to reach the
btrfs_fs_info struct. Change these functions to receive a btrfs_fs_info
struct instead of a *file.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The compression type upper limit constant is the same as the last value
and this is confusing. In order to keep coding style consistent, use
BTRFS_NR_COMPRESS_TYPES as the total number that follows the idom of
'NR' being one more than the last value.
Signed-off-by: Chengguang Xu <cgxu519@mykernel.net>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The attribute is more relaxed than const and the functions could
dereference pointers, as long as the observable state is not changed. We
do have such functions, based on -Wsuggest-attribute=pure .
The visible effects of this patch are negligible, there are differences
in the assembly but hard to summarize.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The parameter is now always set to NULL and could be dropped. The last
user was get_default_root but that got reworked in 05dbe6837b ("Btrfs:
unify subvol= and subvolid= mounting") and the parameter became unused.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The two ioctls START_SYNC and WAIT_SYNC were mistakenly marked as
deprecated and scheduled for removal but we actualy do use them for
'btrfs subvolume delete -C/-c'. The deprecated thing in ebc87351e5
should have been just the async flag for subvolume creation.
The deprecation has been added in this development cycle, remove it
until it's time.
Fixes: ebc87351e5 ("btrfs: Deprecate BTRFS_SUBVOL_CREATE_ASYNC flag")
Signed-off-by: David Sterba <dsterba@suse.com>
