This change fixes an issue when removing a device and writing
all super blocks run simultaneously. Here's the steps necessary
for the issue to happen:
1) disk-io.c:write_all_supers() gets a number of N devices from the
super_copy, so it will not panic if it fails to write super blocks
for N - 1 devices;
2) Then it tries to acquire the device_list_mutex, but blocks because
volumes.c:btrfs_rm_device() got it first;
3) btrfs_rm_device() removes the device from the list, then unlocks the
mutex and after the unlock it updates the number of devices in
super_copy to N - 1.
4) write_all_supers() finally acquires the mutex, iterates over all the
devices in the list and gets N - 1 errors, that is, it failed to write
super blocks to all the devices;
5) Because write_all_supers() thinks there are a total of N devices, it
considers N - 1 errors to be ok, and therefore won't panic.
So this change just makes sure that write_all_supers() reads the number
of devices from super_copy after it acquires the device_list_mutex.
Conversely, it changes btrfs_rm_device() to update the number of devices
in super_copy before it releases the device list mutex.
The code path to add a new device (volumes.c:btrfs_init_new_device),
already has the right behaviour: it updates the number of devices in
super_copy while holding the device_list_mutex.
The only code path that doesn't lock the device list mutex
before updating the number of devices in the super copy is
disk-io.c:next_root_backup(), called by open_ctree() during
mount time where concurrency issues can't happen.
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
A user was reporting weird warnings from btrfs_put_delayed_ref() and I noticed
that we were doing this list_del_init() on our head ref outside of
delayed_refs->lock. This is a problem if we have people still on the list, we
could end up modifying old pointers and such. Fix this by removing us from the
list before we do our run_delayed_ref on our head ref. Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
We were unconditionally clearing our runtime flag on the inode on error when
trying to insert an orphan item. This is wrong in the case of -EEXIST since we
obviously have an orphan item. This was causing us to not do the correct
cleanup of our orphan items which caused issues on cleanup. This happens
because currently when truncate fails we just leave the orphan item on there so
it can be cleaned up, so if we go to remove the file later we will hit this
issue. What we do for truncate isn't right either, but we shouldn't screw this
sort of thing up on error either, so fix this and then I'll fix truncate in a
different patch. Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Send was just sending everything it found, even if the extent was a hole. This
is unpleasant for users, so just skip holes when we are sending. This will also
skip sending prealloc extents since the send spec doesn't have a prealloc
command. Eventually we will add a prealloc command and rev the send version so
we can send down the prealloc info. Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
The name buffer is not terminated by a '\0' character,
therefore it needs to be printed with %.*s and use the
length of the buffer.
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
sector_t may be either "u64" (always 64 bit) or "unsigned long" (32 or 64
bit). Casting it to "unsigned long" will truncate it on 32-bit platforms
where CONFIG_LBDAF=y.
Cast to "unsigned long long" and format using "ll" instead.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
PAGE_CACHE_SIZE == PAGE_SIZE is "unsigned long" everywhere, so there's no
need to cast it to "unsigned long".
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Internally, btrfs_header_chunk_tree_uuid() calculates an unsigned long, but
casts it to a pointer, while all callers cast it to unsigned long again.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Internally, btrfs_header_fsid() calculates an unsigned long, but casts
it to a pointer, while all callers cast it to unsigned long again.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Internally, btrfs_dev_extent_chunk_tree_uuid() calculates an unsigned long,
but casts it to a pointer, while all callers cast it to unsigned long
again.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
All callers of btrfs_device_fsid() cast its return type to unsigned long.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
All callers of btrfs_device_uuid() cast its return type to unsigned long.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
mirror_num is always "int", hence don't cast it to "unsigned long long" and
format it as a 64-bit number.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
PAGE_SIZE is "unsigned long" everywhere, so there's no need to cast it to
"unsigned long long" and format it as a 64-bit number.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
The internal btrfs device id is a u64, hence make the constant
BTRFS_DEV_REPLACE_DEVID "unsigned long long" as well, so we no longer need
a cast to print it.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
u64 is "unsigned long long" on all architectures now, so there's no need to
cast it when formatting it using the "ll" length modifier.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
It turns out we don't properly rollback in-core btrfs_device state on
umount. We zero out ->bdev, ->in_fs_metadata and that's about it. In
particular, we don't zero out ->generation, and this can lead to us
refusing a mount -- a non-NULL fs_devices->latest_bdev is essential, but
btrfs_close_extra_devices will happily assign NULL to ->latest_bdev if
the first device on the dev_list happens to be missing and consequently
has no bdev attached. This happens because since commit a6b0d5c8
btrfs_close_extra_devices adjusts ->latest_bdev, and in doing that,
relies on the ->generation. Fix this, and possibly other problems, by
zeroing out everything except for what device_list_add sets, so that a
mount right after insmod and 'btrfs dev scan' is no different from any
later mount in this respect.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
In the spirit of btrfs_alloc_device, add a helper for allocating and
doing some common initialization of btrfs_fs_devices struct.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Currently btrfs_device is allocated ad-hoc in a few different places,
and as a result not all fields are initialized properly. In particular,
readahead state is only initialized in device_list_add (at scan time),
and not in btrfs_init_new_device (when the new device is added with
'btrfs dev add'). Fix this by adding an allocation helper and switch
everybody but __btrfs_close_devices to it. (__btrfs_close_devices is
dealt with in a later commit.)
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
find_next_devid() knows which root to search, so it should take an
fs_info instead of an arbitrary root.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
If you start the replace procedure on a read only filesystem, at
the end the procedure fails to write the updated dev_items to the
chunk tree. The problem is that this error is not indicated except
for a WARN_ON(). If the user now thinks that everything was done
as expected and destroys the source device (with mkfs or with a
hammer). The next mount fails with "failed to read chunk root" and
the filesystem is gone.
This commit adds code to fail the attempt to start the replace
procedure if the filesystem is mounted read-only.
Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Cc: <stable@vger.kernel.org> # 3.10+
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
After we set force_compress with a new value (which was not being done
while holding the inode mutex), if an error happens and we jump to
the label out_ra, the force_compress property of the inode is not set
to BTRFS_COMPRESS_NONE (unlike in the case where no errors happen).
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
This should never be needed, but since all functions are there
to check and rebuild the UUID tree, a mount option is added that
allows to force this check and rebuild procedure.
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>
If the filesystem was mounted with an old kernel that was not
aware of the UUID tree, this is detected by looking at the
uuid_tree_generation field of the superblock (similar to how
the free space cache is doing it). If a mismatch is detected
at mount time, a thread is started that does two things:
1. Iterate through the UUID tree, check each entry, delete those
entries that are not valid anymore (i.e., the subvol does not
exist anymore or the value changed).
2. Iterate through the root tree, for each found subvolume, add
the UUID tree entries for the subvolume (if they are not
already there).
This mechanism is also used to handle and repair errors that
happened during the initial creation and filling of the tree.
The update of the uuid_tree_generation field (which indicates
that the state of the UUID tree is up to date) is blocked until
all create and repair operations are successfully completed.
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>
In order to be able to detect the case that a filesystem is mounted
with an old kernel, add a uuid-tree-gen field like the free space
cache is doing it. It is part of the super block and written with
each commit. Old kernels do not know this field and don't update it.
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>
When the UUID tree is initially created, a task is spawned that
walks through the root tree. For each found subvolume root_item,
the uuid and received_uuid entries in the UUID tree are added.
This is such a quick operation so that in case somebody wants
to unmount the filesystem while the task is still running, the
unmount is delayed until the UUID tree building task is finished.
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>
When a new subvolume or snapshot is created, a new UUID item is added
to the UUID tree. Such items are removed when the subvolume is deleted.
The ioctl to set the received subvolume UUID is also touched and will
now also add this received UUID into the UUID tree together with the
ID of the subvolume. The latter is also done when read-only snapshots
are created which inherit all the send/receive information from the
parent subvolume.
User mode programs use the BTRFS_IOC_TREE_SEARCH ioctl to search and
read in the UUID tree.
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>
This tree is not created by mkfs.btrfs. Therefore when a filesystem
is mounted writable and the UUID tree does not exist, this tree is
created if required. The tree is also added to the fs_info structure
and initialized, but this commit does not yet read or write UUID tree
elements.
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>
This commit adds support to print UUID tree elements to print-tree.c.
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>
Mapping UUIDs to subvolume IDs is an operation with a high effort
today. Today, the algorithm even has quadratic effort (based on the
number of existing subvolumes), which means, that it takes minutes
to send/receive a single subvolume if 10,000 subvolumes exist. But
even linear effort would be too much since it is a waste. And these
data structures to allow mapping UUIDs to subvolume IDs are created
every time a btrfs send/receive instance is started.
It is much more efficient to maintain a searchable persistent data
structure in the filesystem, one that is updated whenever a
subvolume/snapshot is created and deleted, and when the received
subvolume UUID is set by the btrfs-receive tool.
Therefore kernel code is added with this commit that is able to
maintain data structures in the filesystem that allow to quickly
search for a given UUID and to retrieve data that is assigned to
this UUID, like which subvolume ID is related to this UUID.
This commit adds a new tree to hold UUID-to-data mapping items. The
key of the items is the full UUID plus the key type BTRFS_UUID_KEY.
Multiple data blocks can be stored for a given UUID, a type/length/
value scheme is used.
Now follows the lengthy justification, why a new tree was added
instead of using the existing root tree:
The first approach was to not create another tree that holds UUID
items. Instead, the items should just go into the top root tree.
Unfortunately this confused the algorithm to assign the objectid
of subvolumes and snapshots. The reason is that
btrfs_find_free_objectid() calls btrfs_find_highest_objectid() for
the first created subvol or snapshot after mounting a filesystem,
and this function simply searches for the largest used objectid in
the root tree keys to pick the next objectid to assign. Of course,
the UUID keys have always been the ones with the highest offset
value, and the next assigned subvol ID was wastefully huge.
To use any other existing tree did not look proper. To apply a
workaround such as setting the objectid to zero in the UUID item
key and to implement collision handling would either add
limitations (in case of a btrfs_extend_item() approach to handle
the collisions) or a lot of complexity and source code (in case a
key would be looked up that is free of collisions). Adding new code
that introduces limitations is not good, and adding code that is
complex and lengthy for no good reason is also not good. That's the
justification why a completely new tree was introduced.
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>
Cc: Josef Bacik <jbacik@fusionio.com>
Cc: Chris Mason <chris.mason@fusionio.com>
Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
make C=2 fs/btrfs/ CF=-D__CHECK_ENDIAN__
I tried to filter out the warnings for which patches have already
been sent to the mailing list, pending for inclusion in btrfs-next.
All these changes should be obviously safe.
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>
If the inode ref key was not found and the current leaf slot
was 0 (first item in the leaf) the code would always return
-ENOENT. This was not correct because the desired inode ref
item might be the last item in the previous leaf.
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
If the path doesn't fit in the input buffer, return ENAMETOOLONG
instead of returning with a success code (0) and a partially
filled and right justified buffer.
Also removed useless buffer pointer check outside the while loop.
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
We have checked 'quota_root' with qgroup_ioctl_lock held before,So
here the check is reduplicate, remove it.
Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
Reviewed-by: Miao Xie <miaox@cn.fujitsu.com>
Reviewed-by: Arne Jansen <sensille@gmx.net>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
btrfs_free_qgroup_config() is not only called by open/close_ctree(),but
also btrfs_disable_quota().And for btrfs_disable_quota(),we have set
'quota_root' to be null before calling btrfs_free_qgroup_config(),so it
is safe to cleanup in-memory structures without lock held.
Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
Reviewed-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
When disabling quota, we should clear out list 'dirty_qgroups',otherwise,
we will get oops if enabling quota again. Fix this by abstracting similar
code from del_qgroup_rb().
Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
Reviewed-by: Miao Xie <miaox@cn.fujitsu.com>
Reviewed-by: Arne Jansen <sensille@gmx.net>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
If you are sending a snapshot and specifying a parent snapshot we will walk the
trees and figure out where they differ and send the differences only. The way
we check for differences are if the leaves aren't the same and if the keys are
not the same within the leaves. So if neither leaf is the same (ie the leaf has
been cow'ed from the parent snapshot) we walk each item in the send root and
check it against the parent root. If the items match exactly then we don't do
anything. This doesn't quite work for inode refs, since they will just have the
name and the parent objectid. If you move the file from a directory and then
remove that directory and re-create a directory with the same inode number as
the old directory and then move that file back into that directory we will
assume that nothing changed and you will get errors when you try to receive.
In order to fix this we need to do extra checking to see if the inode ref really
is the same or not. So do this by passing down BTRFS_COMPARE_TREE_SAME if the
items match. Then if the key type is an inode ref we can do some extra
checking, otherwise we just keep processing. The extra checking is to look up
the generation of the directory in the parent volume and compare it to the
generation of the send volume. If they match then they are the same directory
and we are good to go. If they don't we have to add them to the changed refs
list.
This means we have to track the generation of the ref we're trying to lookup
when we iterate all the refs for a particular inode. So in the case of looking
for new refs we have to get the generation from the parent volume, and in the
case of looking for deleted refs we have to get the generation from the send
volume to compare with.
There was also the issue of using a ulist to keep track of the directories we
needed to check. Because we can get a deleted ref and a new ref for the same
inode number the ulist won't work since it indexes based on the value. So
instead just dup any directory ref we find and add it to a local list, and then
process that list as normal and do away with using a ulist for this altogether.
Before we would fail all of the tests in the far-progs that related to moving
directories (test group 32). With this patch we now pass these tests, and all
of the tests in the far-progs send testing suite. Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
The plan is to have a bunch of unit tests that run when btrfs is loaded when you
build with the appropriate config option. My ultimate goal is to have a test
for every non-static function we have, but at first I'm going to focus on the
things that cause us the most problems. To start out with this just adds a
tests/ directory and moves the existing free space cache tests into that
directory and sets up all of the infrastructure. Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
I noticed while looking at a deadlock that we are always starting a transaction
in cow_file_range(). This isn't really needed since we only need a transaction
if we are doing an inline extent, or if the allocator needs to allocate a chunk.
So push down all the transaction start stuff to be closer to where we actually
need a transaction in all of these cases. This will hopefully reduce our write
latency when we are committing often. Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
I added a patch where we started taking the ordered operations mutex when we
waited on ordered extents. We need this because we splice the list and process
it, so if a flusher came in during this scenario it would think the list was
empty and we'd usually get an early ENOSPC. The problem with this is that this
lock is used in transaction committing. So we end up with something like this
Transaction commit
-> wait on writers
Delalloc flusher
-> run_ordered_operations (holds mutex)
->wait for filemap-flush to do its thing
flush task
-> cow_file_range
->wait on btrfs_join_transaction because we're commiting
some other task
-> commit_transaction because we notice trans->transaction->flush is set
-> run_ordered_operations (hang on mutex)
We need to disentangle the ordered operations flushing from the delalloc
flushing, since they are separate things. This solves the deadlock issue I was
seeing. Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
There are several places where we BUG_ON() if we fail to remove the orphan items
and such, which is not ok, so remove those and either abort or just carry on.
This also fixes a problem where if we couldn't start a transaction we wouldn't
actually remove the orphan item reserve for the inode. Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Eric pointed out that btrfs will happily allow you to delete the default subvol.
This is a problem obviously since the next time you go to mount the file system
it will freak out because it can't find the root. Fix this by adding a check to
see if our default subvol points to the subvol we are trying to delete, and if
it does not allowing it to happen. Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
We have logic to see if we've already created a parent directory by check to see
if an inode inside of that directory has a lower inode number than the one we
are currently processing. The logic is that if there is a lower inode number
then we would have had to made sure the directory was created at that previous
point. The problem is that subvols inode numbers count from the lowest objectid
in the root tree, which may be less than our current progress. So just skip if
our dir item key is a root item. This fixes the original test and the xfstest
version I made that added an extra subvol create. Thanks,
Reported-by: Emil Karlson <jekarlson@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
This patch adds an ioctl, BTRFS_IOC_FILE_EXTENT_SAME which will try to
de-duplicate a list of extents across a range of files.
Internally, the ioctl re-uses code from the clone ioctl. This avoids
rewriting a large chunk of extent handling code.
Userspace passes in an array of file, offset pairs along with a length
argument. The ioctl will then (for each dedupe) do a byte-by-byte comparison
of the user data before deduping the extent. Status and number of bytes
deduped are returned for each operation.
Signed-off-by: Mark Fasheh <mfasheh@suse.de>
Reviewed-by: Zach Brown <zab@redhat.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
We want this for btrfs_extent_same. Basically readpage and friends do their
own extent locking but for the purposes of dedupe, we want to have both
files locked down across a set of readpage operations (so that we can
compare data). Introduce this variant and a flag which can be set for
extent_read_full_page() to indicate that we are already locked.
Partial credit for this patch goes to Gabriel de Perthuis <g2p.code@gmail.com>
as I have included a fix from him to the original patch which avoids a
deadlock on compressed extents.
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>
There's some 250+ lines here that are easily encapsulated into their own
function. I don't change how anything works here, just create and document
the new btrfs_clone() function from btrfs_ioctl_clone() code.
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>
The range locking in btrfs_ioctl_clone is trivially broken out into it's own
function. This reduces the complexity of btrfs_ioctl_clone() by a small bit
and makes that locking code available to future functions in
fs/btrfs/ioctl.c
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>
