Steps to reproduce:
 # mkfs.btrfs -d single -m single <disk0> <disk1>
 # mount -o ro <disk0> <mnt0>
 # mount -o ro <disk0> <mnt1>
 # mount -o remount,rw <mnt0>
 # umount <mnt0>
 # btrfs device delete <disk1> <mnt1>

We can remove a device from a R/O filesystem. The reason is that we just check
the R/O flag of the super block object. It is not enough, because the kernel
may set the R/O flag only for the mount point. We need invoke

	mnt_want_write_file()

to do a full check.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

Steps to reproduce:
 # mkfs.btrfs <partition>
 # mount -o ro <partition> <mnt0>
 # mount -o ro <partition> <mnt1>
 # mount -o remount,rw <mnt0>
 # umount <mnt0>
 # btrfs fi resize 10g <mnt1>

We re-sized a R/O filesystem. The reason is that we just check the R/O flag
of the super block object. It is not enough, because the kernel may set the
R/O flag only for the mount point. We need invoke mnt_want_write_file() to
do a full check.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

When wen want to set the default subvolume, we must get write access, or
we will change the R/O file system.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

If there is no running transaction in the fs, we needn't start a new one when
we want to start sync.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

Since we have gotten the root in the caller, just pass it into
btrfs_ioctl_{start, wait}_sync() directly.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

This is the commit that allows to start the device replace
procedure.

An ioctl() interface is added that supports starting and
canceling the device replace procedure, and to retrieve
the status and progress.
Signed-off-by: NStefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

This patch adds some code to disallow operations on the device that
is used as the target for the device replace operation.
Signed-off-by: NStefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

Btrfs admin operations that are manually started from user mode
and that cannot be executed at the same time return -EINPROGRESS.
A common way to enter and leave this locked section is introduced
since it used to be specific to the balance operation.
Signed-off-by: NStefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

A small number of functions that are used in a device replace
procedure when the operation is resumed at mount time are unable
to pass the same root pointer that would be used in the regular
(ioctl) context. And since the root pointer is not required, only
the fs_info is, the root pointer argument is replaced with the
fs_info pointer argument.
Signed-off-by: NStefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

When creating a snapshot, failing to commit a transaction can end up
with aborting the transaction, following by doing a cleanup for it, where
we'll free all snapshots pending to disk.

So we check it and avoid double free on pending snapshots.
Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

Remove an invalid size check up from btrfs_shrink_dev().

The new size should not larger than the device->total_bytes as it was
already verified before coming to here(i.e. new_size < old_size).

Remove invalid check up for btrfs_shrink_dev().
Signed-off-by: NJie Liu <jeff.liu@oracle.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

We BUG if we fail to commit the transaction when creating a snapshot, which
is just obnoxious.  Remove the BUG_ON().  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>

Currently if len argument in btrfs_ioctl_fitrim() is smaller than
one FSB we will continue and finally return 0 bytes discarded.
However if the length to discard is smaller then file system block
we should really return EINVAL.
Signed-off-by: NLukas Czerner <lczerner@redhat.com>

In order to accomodate retrying path-based syscalls, we need to add a
new "type" argument to audit_inode_child. This will tell us whether
we're looking for a child entry that represents a create or a delete.

If we find a parent, don't automatically assume that we need to create a
new entry. Instead, use the information we have to try to find an
existing entry first. Update it if one is found and create a new one if
not.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Most of the callers get called with an inode and dentry in the reverse
order. The compiler then has to reshuffle the arg registers and/or
stack in order to pass them on to audit_inode_child.

Reverse those arguments for a micro-optimization.
Reported-by: NEric Paris <eparis@redhat.com>
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

So far the return code of barrier_all_devices() is ignored, which
means that errors are ignored. The result can be a corrupt
filesystem which is not consistent.
This commit adds code to evaluate the return code of
barrier_all_devices(). The normal btrfs_error() mechanism is used to
switch the filesystem into read-only mode when errors are detected.

In order to decide whether barrier_all_devices() should return
error or success, the number of disks that are allowed to fail the
barrier submission is calculated. This calculation accounts for the
worst RAID level of metadata, system and data. If single, dup or
RAID0 is in use, a single disk error is already considered to be
fatal. Otherwise a single disk error is tolerated.

The calculation of the number of disks that are tolerated to fail
the barrier operation is performed when the filesystem gets mounted,
when a balance operation is started and finished, and when devices
are added or removed.
Signed-off-by: NStefan Behrens <sbehrens@giantdisaster.de>

Btrfs uses inclusive range end for lock_extent(), unlock_extent() and
related functions, so we made off-by-one errors in file clone.

This fixes it and also fixes some style problems.
Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>

Hi,

the patch si simple, but it has user visible impact and I'm not quite sure how
to resolve it.

In short, $subj says it, chattr -C supports it and we want to use it.

The conditions that acutally allow to change the NOCOW flag are clear. What if
I try to set the flag on a file that is not empty? Options:

1) whole ioctl will fail, EINVAL
2.1) ioctl will succeed, the NOCOW flag will be silently removed, but the file
     will stay COW-ed and checksummed
2.2) ioctl will succeed, flag will not be removed and a syslog message will
     warn that the COW flag has not been changed
2.2.1) dtto, no syslog message

Man page of chattr states that

 "If it is set on a file which already has data blocks, it is undefined when
 the blocks assigned to the file will be fully stable."

Yes, it's undefined and with current implementation it'll never happen. So from
this end, the user cannot expect anything. I'm trying to find a reasonable
behaviour, so that a command like 'chattr -R -aijS +C' to tweak a broad set of
flags in a deep directory does not fail unnecessarily and does not pollute the
log.

My personal preference is 2.2.1, but my dev's oppinion is skewed, not counting
the fact that I know the code and otherwise would look there before consulting
the documentation.

The patch implements 2.2.1.

david

-------------8<-------------------
From: David Sterba <dsterba@suse.cz>

It's safe to turn off checksums for a zero sized file.

http://thread.gmane.org/gmane.comp.file-systems.btrfs/18030

"We cannot switch on NODATASUM for a file that already has extents that
are checksummed. The invariant here is that either all the extents or
none are checksummed.

Theoretically it's possible to add/remove all checksums from a given
file, but it's a potentially longtime operation, the file has to be in
some intermediate state where the checksums partially exist but have to
be ignored (for the csum->nocsum) until the file is fully converted,
this brings more special cases to extent handling, it has to survive
power failure and remain consistent, and probably needs to be restarted
after next mount."
Signed-off-by: NDavid Sterba <dsterba@suse.cz>

This is the change of the kernel side.

Translation of logical to inode used to have an upper limit 4k on
inode container's size, but the limit is not large enough for a data
with a great many of refs, so when resolving logical address,
we can end up with
"ioctl ret=0, bytes_left=0, bytes_missing=19944, cnt=510, missed=2493"

This changes to regard 64k as the upper limit and use vmalloc instead of
kmalloc to get memory more easily.
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>

We already have a helper, iterate_inodes_from_logical(), for logical resolve,
so just use it.
Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>

In logical resolve, we parse extent_from_logical()'s 'ret' as a kind of flag.

It is possible to lose our errors because
(-EXXXX & BTRFS_EXTENT_FLAG_TREE_BLOCK) is true.

I'm not sure if it is on purpose, it just looks too hacky if it is.
I'd rather use a real flag and a 'ret' to catch errors.
Acked-by: NJan Schmidt <list.btrfs@jan-o-sch.net>
Signed-off-by: NLiu Bo <liub.liubo@gmail.com>

We're going to use this flag EXTENT_DEFRAG to indicate which range
belongs to defragment so that we can implement snapshow-aware defrag:

We set the EXTENT_DEFRAG flag when dirtying the extents that need
defragmented, so later on writeback thread can differentiate between
normal writeback and writeback started by defragmentation.
Original-Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>

We should insert/update 6 items(root ref, root backref, dir item, dir index,
root item and parent inode) when creating a snapshot, not 5 items, fix it.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>

Sometimes we need choose the method of the reservation according to the type
of the block reservation, such as the reservation for the delayed inode update.
Now we identify the type just by comparing the address of the reservation
variants, it is very ugly if it is a temporary one because we need compare it
with all the common reservation variants. So we add a new "type" field to keep
the type the reservation variants.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>

I audited all users of btrfs_drop_extents and found that nobody actually uses
the hint_byte argument.  I'm sure it was used for something at some point but
it's not used now, and the way the pinning works the disk bytenr would never be
immediately useful anyway so lets just remove it.  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>

At least for the vm workload.  Currently on fsync we will

1) Truncate all items in the log tree for the given inode if they exist

and

2) Copy all items for a given inode into the log

The problem with this is that for things like VMs you can have lots of
extents from the fragmented writing behavior, and worst yet you may have
only modified a few extents, not the entire thing.  This patch fixes this
problem by tracking which transid modified our extent, and then when we do
the tree logging we find all of the extents we've modified in our current
transaction, sort them and commit them.  We also only truncate up to the
xattrs of the inode and copy that stuff in normally, and then just drop any
extents in the range we have that exist in the log already.  Here are some
numbers of a 50 meg fio job that does random writes and fsync()s after every
write

		Original	Patched
SATA drive	82KB/s		140KB/s
Fusion drive	431KB/s		2532KB/s

So around 2-6 times faster depending on your hardware.  There are a few
corner cases, for example if you truncate at all we have to do it the old
way since there is no way to be sure what is in the log is ok.  This
probably could be done smarter, but if you write-fsync-truncate-write-fsync
you deserve what you get.  All this work is in RAM of course so if your
inode gets evicted from cache and you read it in and fsync it we'll do it
the slow way if we are still in the same transaction that we last modified
the inode in.

The biggest cool part of this is that it requires no changes to the recovery
code, so if you fsync with this patch and crash and load an old kernel, it
will run the recovery and be a-ok.  I have tested this pretty thoroughly
with an fsync tester and everything comes back fine, as well as xfstests.
Thanks,
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Cc: Chris Mason <chris.mason@fusionio.com>
Acked-by: NSerge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>

"trans->transid" is cpu endian but we want to store the data as little
endian.  "item->ctime.nsec" is only 32 bits, not 64.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>

We got a recursive lock in mksubvol because the caller already held
a lock. I think we got into this due to a merge error. Commit a874a63e
removed the mnt_want_write call from btrfs_mksubvol and added a
replacement call to mnt_want_write_file in btrfs_ioctl_snap_create_transid.
Commit e7848683 however tried to move all calls to mnt_want_write above
i_mutex. So somewhere while merging this, it got mixed up. The
solution is to remove the mnt_want_write call completely from
mksubvol.
Reported-by: NDavid Sterba <dave@jikos.cz>
Signed-off-by: NAlexander Block <ablock84@googlemail.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

When mnt_want_write() starts to handle freezing it will get a full lock
semantics requiring proper lock ordering. So push mnt_want_write() call
consistently outside of i_mutex.

CC: Chris Mason <chris.mason@oracle.com>
CC: linux-btrfs@vger.kernel.org
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This patch introduces the BTRFS_IOC_SEND ioctl that is
required for send. It allows btrfs-progs to implement
full and incremental sends. Patches for btrfs-progs will
follow.
Signed-off-by: NAlexander Block <ablock84@googlemail.com>
Reviewed-by: NDavid Sterba <dave@jikos.cz>
Reviewed-by: NArne Jansen <sensille@gmx.net>
Reviewed-by: NJan Schmidt <list.btrfs@jan-o-sch.net>
Reviewed-by: NAlex Lyakas <alex.bolshoy.btrfs@gmail.com>

This patch introduces uuids for subvolumes. Each
subvolume has it's own uuid. In case it was snapshotted,
it also contains parent_uuid. In case it was received,
it also contains received_uuid.

It also introduces subvolume ctime/otime/stime/rtime. The
first two are comparable to the times found in inodes. otime
is the origin/creation time and ctime is the change time.
stime/rtime are only valid on received subvolumes.
stime is the time of the subvolume when it was
sent. rtime is the time of the subvolume when it was
received.

Additionally to the times, we have a transid for each
time. They are updated at the same place as the times.

btrfs receive uses stransid and rtransid to find out
if a received subvolume changed in the meantime.

If an older kernel mounts a filesystem with the
extented fields, all fields become invalid. The next
mount with a new kernel will detect this and reset the
fields.
Signed-off-by: NAlexander Block <ablock84@googlemail.com>
Reviewed-by: NDavid Sterba <dave@jikos.cz>
Reviewed-by: NArne Jansen <sensille@gmx.net>
Reviewed-by: NJan Schmidt <list.btrfs@jan-o-sch.net>
Reviewed-by: NAlex Lyakas <alex.bolshoy.btrfs@gmail.com>

In support of the recently added capability to remount with lzo
compression, provide a helper function to check the compression
INCOMPAT flags when remounting with lzo compression, and set
the flags if necessary.

Also, implement the new helper function when defragmenting with
explicit lzo compression and when setting the default subvolume.
Signed-off-by: NMitch Harder <mitch.harder@sabayonlinux.org>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

Lift the EXDEV condition and allow different root trees for files being
cloned, then pass source inode's root when searching for extents.
Cloning is not allowed to cross vfsmounts, ie. when two subvolumes from
one filesystem are mounted separately.
Signed-off-by: NDavid Sterba <dsterba@suse.cz>

$ mkfs.btrfs /dev/sdb7
$ btrfstune -S1 /dev/sdb7
$ mount /dev/sdb7 /mnt/btrfs
mount: block device /dev/sdb7 is write-protected, mounting read-only
$ btrfs dev add /dev/sdb8 /mnt/btrfs/

Now we get a btrfs in which mnt flags has readonly but sb flags does
not.  So for those ioctls that only check sb flags with MS_RDONLY, it
is going to be a problem.
Setting subvolume flags is such an ioctl, we should use mnt_want_write_file()
to check RO flags.
Signed-off-by: NLiu Bo <liubo2009@cn.fujitsu.com>

mnt_want_write_file is faster when file has been opened for write.
Signed-off-by: NLiu Bo <liubo2009@cn.fujitsu.com>

mnt_want_write() and mnt_want_write_file() will check sb->s_flags with
MS_RDONLY, and we don't need to do it ourselves.
Signed-off-by: NLiu Bo <liubo2009@cn.fujitsu.com>