Currently holes are sent as writes full of zeroes, which results in
unnecessarily using disk space at the receiving end and increasing the
stream size.
In some cases we avoid sending writes of zeroes, like during a full
send operation where we just skip writes for holes.
But for some cases we fill previous holes with writes of zeroes too, like
in this scenario:
1) We have a file with a hole in the range [2M, 3M), we snapshot the
subvolume and do a full send. The range [2M, 3M) stays as a hole at
the receiver since we skip sending write commands full of zeroes;
2) We punch a hole for the range [3M, 4M) in our file, so that now it
has a 2M hole in the range [2M, 4M), and snapshot the subvolume.
Now if we do an incremental send, we will send write commands full
of zeroes for the range [2M, 4M), removing the hole for [2M, 3M) at
the receiver.
We could improve cases such as this last one by doing additional
comparisons of file extent items (or their absence) between the parent
and send snapshots, but that's a lot of code to add plus additional CPU
and IO costs.
Since the send stream v2 already has a fallocate command and btrfs-progs
implements a callback to execute fallocate since the send stream v2
support was added to it, update the kernel to use fallocate for punching
holes for V2+ streams.
Test coverage is provided by btrfs/284 which is a version of btrfs/007
that exercises send stream v2 instead of v1, using fsstress with random
operations and fssum to verify file contents.
Link: https://github.com/kdave/btrfs-progs/issues/1001
CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There's no point in converting the return values from strcmp() as all we
need is that it returns a negative value if the first argument is less
than the second, a positive value if it's greater and 0 if equal. We do
not have a need for -1 instead of any other negative value and no need
for 1 instead of any other positive value - that's all that rb_find()
needs and no where else we need specific negative and positive values.
So remove the intermediate local variable and checks and return directly
the result from strcmp().
This also reduces the module's text size.
Before:
$ size fs/btrfs/btrfs.ko
text data bss dec hex filename
1888116 161347 16136 2065599 1f84bf fs/btrfs/btrfs.ko
After:
$ size fs/btrfs/btrfs.ko
text data bss dec hex filename
1888052 161347 16136 2065535 1f847f fs/btrfs/btrfs.ko
Reviewed-by: Boris Burkov <boris@bur.io>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
strcpy() is discouraged from use due to lack of bounds checking.
Replaces it with strscpy(), the recommended alternative for null
terminated strings, to follow best practices.
There are instances where strscpy() cannot be used such as where both
the source and destination are character pointers. In that instance we
can use sysfs_emit().
Link: https://github.com/KSPP/linux/issues/88
Suggested-by: Anthony Iliopoulos <ailiop@suse.com>
Signed-off-by: Brahmajit Das <bdas@suse.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Since 'snprintf()' returns the number of characters which would
be emitted and output truncation is handled by 'ASSERT()', it
should be safe to use that return value instead of the subsequent
calls to 'strlen()' in 'gen_unique_name()'.
This also reduces the module's text size.
Before:
$ size fs/btrfs/btrfs.ko
text data bss dec hex filename
1897006 161571 16136 2074713 1fa859 fs/btrfs/btrfs.ko
After:
$ size fs/btrfs/btrfs.ko
text data bss dec hex filename
1896848 161571 16136 2074555 1fa7bb fs/btrfs/btrfs.ko
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
Reviewed-by: Filipe Manana <fdmanana@suse.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 debugging prints for each emitted send command and other
related actions. This does not seem right as the number of commands can
be high and dumping that to the system log will likely hit some rate
limiting. This should be done by trace points that are more lightweight
and can keep up with high frequency.
Signed-off-by: David Sterba <dsterba@suse.com>
Using the helper makes it a bit more clear that we're accessing the
first list entry.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The use of ASSERT(0) is maybe useful for some cases but more like a
notice for developers. Assertions can be compiled in independently so
convert it to a debugging helper.
The difference is that it's just a warning and will not end up in BUG().
The converted cases are in connection with proper error handling.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently put_file_data() can only accept a page sized folio. However
the function itself is not that complex, it's just copying data from
filemap folio into the send buffer.
Make it support large data folios:
- Change the loop to use file offset instead of page index
- Calculate @pg_offset and @cur_len after getting the folio
- Remove the "WARN_ON(folio_order(folio));" line
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The again label is here to retry to get the folio for the current index.
When triggering that label, there is no advance of the iterator.
So it can be replaced by a simple "continue" and remove the again label.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
It's an internal function and most of the time the callers are doing a lot
of BTRFS_I() calls on the returned VFS inode to get the btrfs inode, so
change the return type to struct btrfs_inode instead.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The 'out' label is pointless as we don't have anything to cleanup anymore
(we used to have an inode to iput), so remove it and make error paths
directly return an error.
Reviewed-by: Qu Wenruo <wqu@suse.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 are doing a lookup of the inode but we don't use it at all. So just
remove this pointless lookup.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The ioctl switch btrfs_ioctl() provides several parameter types for
convenience so we don't have to do the conversion in the callbacks.
Pass root pointers to the send related functions.
Signed-off-by: David Sterba <dsterba@suse.com>
There's no longer any need for the 'out' label as there are no resources
to cleanup anymore in case of an error and we can directly return if
begin_cmd() fails.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Whenever we issue a command we allocate a path and then compute it. For
the current inode this is not necessary since we have one preallocated
and computed in the send context structure, so we can use it instead
and avoid allocating and freeing a path.
For example if we have 100 extents to send (100 write commands) for a
file, we are allocating and freeing paths 100 times.
So improve on this by avoiding path allocation and freeing whenever a
command is for the current inode by using the current inode's path
stored in the send context structure.
A test was run before applying this patch and the previous one in the
series:
"btrfs: send: keep the current inode's path cached"
The test script is the following:
$ cat test.sh
#!/bin/bash
DEV=/dev/nullb0
MNT=/mnt/nullb0
mkfs.btrfs -f $DEV > /dev/null
mount $DEV $MNT
DIR="$MNT/one/two/three/four"
FILE="$DIR/foobar"
mkdir -p $DIR
# Create some empty files to get a deeper btree and therefore make
# path computations slower.
for ((i = 1; i <= 30000; i++)); do
echo -n > "$DIR/filler_$i"
done
for ((i = 0; i < 10000; i += 2)); do
offset=$(( i * 4096 ))
xfs_io -f -c "pwrite -S 0xab $offset 4K" $FILE > /dev/null
done
btrfs subvolume snapshot -r $MNT $MNT/snap
start=$(date +%s%N)
btrfs send -f /dev/null $MNT/snap
end=$(date +%s%N)
echo -e "\nsend took $(( (end - start) / 1000000 )) milliseconds"
umount $MNT
Result before applying the 2 patches: 1121 milliseconds
Result after applying the 2 patches: 815 milliseconds (-31.6%)
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Whenever we need to send a command for the current inode, like sending
writes, xattr updates, truncates, utimes, etc, we compute the inode's
path each time, which implies doing some memory allocations and traversing
the inode hierarchy to extract the name of the inode and each ancestor
directory, and that implies doing lookups in the subvolume tree amongst
other operations.
Most of the time, by far, the current inode's path doesn't change while
we are processing it (like if we need to issue 100 write commands, the
path remains the same and it's pointless to compute it 100 times).
To avoid this keep the current inode's path cached in the send context
and invalidate it or update it whenever it's needed (after unlinks or
renames).
A performance test, and its results, is mentioned in the next patch in
the series (subject: "btrfs: send: avoid path allocation for the current
inode when issuing commands").
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There is no need to have an 'out' label and jump into it since there are
no resource cleanups to perform (release locks, free memory, etc), so
make this simpler by removing the label and goto and instead return
directly.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There is no need to have an 'out' label and jump into it since there are
no resource cleanups to perform (release locks, free memory, etc), so
make this simpler by removing the label and goto and instead return
directly.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There is no need to have an 'out' label and jump into it since there are
no resource cleanups to perform (release locks, free memory, etc), so
make this simpler by removing the label and goto and instead return
directly.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There is no need to have an 'out' label and jump into it since there are
no resource cleanups to perform (release locks, free memory, etc), so
make this simpler by removing the label and goto and instead return
directly.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There's no need for the 'out' label as there are no resources to cleanup
in case of an error and we can directly return if begin_cmd() fails.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There is no need to have an 'out' label and jump into it since there are
no resource cleanups to perform (release locks, free memory, etc), so
make this simpler by removing the label and goto and instead return
directly.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There's no need for the 'ret' variable, we can just return directly the
result of the call to iterate_dir_item().
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There is no need to have an 'out' label and jump into it since there are
no resource cleanups to perform (release locks, free memory, etc), so
make this simpler by removing the label and goto and instead return
directly.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There is no need to have an 'out' label and jump into it since there are
no resource cleanups to perform (release locks, free memory, etc), so
make this simpler by removing the label and goto and instead return
directly.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There is no need to have an 'out' label and jump into it since there are
no resource cleanups to perform (release locks, free memory, etc), so
make this simpler by removing the label and goto and instead return
directly.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There is no need to have an 'out' label and jump into it since there are
no resource cleanups to perform (release locks, free memory, etc), so
make this simpler by removing the label and goto and instead return
directly.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There is no need to have an 'out' label and jump into it since there are
no resource cleanups to perform (release locks, free memory, etc), so
make this simpler by removing the label and goto and instead return
directly.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There's no need for the 'out' label as there are no resources to cleanup
in case of an error and we can directly return if begin_cmd() fails.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Extract the logic to rename the current inode at process_recorded_refs()
into a helper function and use it, therefore removing duplicated logic
and making it easier for an upcoming patch by avoiding yet more duplicated
logic.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We have several local variables at process_recorded_refs() that are used
as booleans, with some of them having a 'bool' type while two of them
having an 'int' type. Change this to make them all use the 'bool' type
which is more clear and to make everything more consistent.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We always send xattrs for the current inode only and both callers of
send_set_xattr() pass a path for the current inode. So move the path
allocation and computation to send_set_xattr(), reducing duplicated
code. This also facilitates an upcoming patch.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There is no need to have an 'out' label and jump into it since there are
no resource cleanups to perform (release locks, free memory, etc), so
make this simpler by removing the label and goto and instead return
directly.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There is no need to have an 'out' label and jump into it since there are
no resource cleanups to perform (release locks, free memory, etc), so
make this simpler by removing the label and goto and instead return
directly.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There is no need to have an 'out' label and jump into it since there are
no resource cleanups to perform (release locks, free memory, etc), so
make this simpler by removing the label and goto and instead return
directly.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When attempting to build a too long path we are currently returning
-ENOMEM, which is very odd and misleading. So update fs_path_ensure_buf()
to return -ENAMETOOLONG instead. Also, while at it, move the WARN_ON()
into the if statement's expression, as it makes it clear what is being
tested and also has the effect of adding 'unlikely' to the statement,
which allows the compiler to generate better code as this condition is
never expected to happen.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There is no need to have an 'out' label and jump into it since there are
no resource cleanups to perform (release locks, free memory, etc), so
make this simpler by removing the label and goto and instead return
directly.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The helper fs_path_add_path() is basically a copy of fs_path_add() and it
can be made a wrapper around fs_path_add(). So do that and also make it
inline and constify its second argument.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There is no need to have an 'out' label and jump into it since there are
no resource cleanups to perform (release locks, free memory, etc), so
make this simpler by removing the label and goto and instead return
directly.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There is no need to have an 'out' label and jump into it since there are
no resource cleanups to perform (release locks, free memory, etc), so
make this simpler by removing the label and goto and instead return
directly.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Several places are hardcoding the path length calculation instead of using
the helper fs_path_len() for that. Update all those places to instead use
fs_path_len().
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The helper function fs_path_len() is trivial and doesn't need to change
its path argument, so make it inline and constify the argument.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There's duplicated logic in both branches of the if statement, so move it
outside the branches.
This also reduces the object code size.
Before this change:
$ size fs/btrfs/btrfs.ko
text data bss dec hex filename
1746279 163600 16920 1926799 1d668f fs/btrfs/btrfs.ko
After this change:
$ size fs/btrfs/btrfs.ko
text data bss dec hex filename
1746047 163592 16920 1926559 1d659f fs/btrfs/btrfs.ko
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The variable ret is being initialized to zero and also later re-assigned
to zero. In both cases the assignment is redundant since the value is
never read after the assignment and hence they can be removed.
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When we call btrfs_read_folio() we get an unlocked folio, so it is possible
for a different thread to concurrently modify folio->mapping. We must
check that this hasn't happened once we do have the lock.
CC: stable@vger.kernel.org # 6.12+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
We're checking if the send root is read-only without being under the
protection of the root's root_item_lock spinlock, which is what protects
the root's flags when clearing the read-only flag, done at
btrfs_ioctl_subvol_setflags(). Furthermore, it should be done in the
same critical section that increments the root's send_in_progress counter,
as btrfs_ioctl_subvol_setflags() clears the read-only flag in the same
critical section that checks the counter's value.
So fix this by moving the read-only check under the critical section
delimited by the root's root_item_lock which also increments the root's
send_in_progress counter.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We're checking if the send root is dead without the protection of the
root's root_item_lock spinlock, which is what protects the root's flags.
The inverse, setting the dead flag on a root, is done under the protection
of that lock, at btrfs_delete_subvolume(). Also checking and updating the
root's send_in_progress counter is supposed to be done in the same
critical section as checking for or setting the root dead flag, so that
these operations are done atomically as a single step (which is correctly
done by btrfs_delete_subvolume()).
So fix this by checking if the send root is dead in the same critical
section that updates the send_in_progress counter, which is protected by
the root's root_item_lock spinlock.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Add an io_uring command for encoded reads, using the same interface as
the existing BTRFS_IOC_ENCODED_READ ioctl.
btrfs_uring_encoded_read() is an io_uring version of
btrfs_ioctl_encoded_read(), which validates the user input and calls
btrfs_encoded_read() to read the appropriate metadata. If we determine
that we need to read an extent from disk, we call
btrfs_encoded_read_regular_fill_pages() through
btrfs_uring_read_extent() to prepare the bio.
The existing btrfs_encoded_read_regular_fill_pages() is changed so that
if it is passed a valid uring_ctx, rather than waking up any waiting
threads it calls btrfs_uring_read_extent_endio(). This in turn copies
the read data back to userspace, and calls io_uring_cmd_done() to
complete the io_uring command.
Because we're potentially doing a non-blocking read,
btrfs_uring_read_extent() doesn't clean up after itself if it returns
-EIOCBQUEUED. Instead, it allocates a priv struct, populates the fields
there that we will need to unlock the inode and free our allocations,
and defers this to the btrfs_uring_read_finished() that gets called when
the bio completes.
Signed-off-by: Mark Harmstone <maharmstone@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Cascaded removal of fs_info that is not needed in several functions.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
