As part of the effort to eliminate BUG_ON as an error handling
technique, we need to determine which errors are actual logic errors,
which are on-disk corruption, and which are normal runtime errors
e.g. -ENOMEM.

Annotating these error cases is helpful to understand and report them.

This patch adds a btrfs_panic() routine that will either panic
or BUG depending on the new -ofatal_errors={panic,bug} mount option.
Since there are still so many BUG_ONs, it defaults to BUG for now but I
expect that to change once the error handling effort has made
significant progress.
Signed-off-by: NJeff Mahoney <jeffm@suse.com>

Since restriper kthread starts involuntarily on mount and can suck cpu
and memory bandwidth add a mount option to forcefully skip it.  The
restriper in that case hangs around in paused state and can be resumed
from userspace when it's convenient.
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

now that we don't need it for sget() anymore...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

the latter can be obtained from the former (by looking as ->tree_root)
just as cheaply as we currently are doing the other way round.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

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

... and don't bother with it after btrfs_fill_super() failure -
->kill_sb() (unlike ->put_super()) will be called even if we
have not got non-NULL ->s_root.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

... all the way up into btrfs_mount().
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

We do not (fortunately) modify ->s_fs_info of superblock on the fly in
btrfs_fill_super(); apparent assignment is a no-op.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

It returns either ERR_PTR(-ve) or sb->s_fs_info.  The latter can
be found by caller just as well, TYVM, no need to return it.  Just
return -ve or 0...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

A new helper: btrfs_alloc_root(fs_info); allocates btrfs_root
and sets ->fs_info.  All places allocating the suckers converted
to it.  At that point we *never* reassign ->fs_info of btrfs_root;
it's set before anyone sees the address of newly allocated
struct btrfs_root and never assigned anywhere else.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Do *NOT* skip doomed superblocks in btrfs_test_super(); we want
sget() to wait for their shutdown to complete.  Since we don't
mutilate ->s_fs_info in ->put_super() anymore (or free what it
used to point to until the superblock is past being findable
by sget()), we can just DTRT there and report a match.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

... and move free_fs_info() to that, out of ->put_super().  Do NOT
set ->s_fs_info to NULL in the latter; we need it for sget() to
be able to see and wait for fs in the middle of umount if we get a
mount/umount race.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

We need fs_info and root to live until the moment when the victim
superblock leaves the list, so we need to postpone free_fs_info()
until after ->put_super().  The call is buried in close_ctree(),
though, so we need to lift it into the callers (including
btrfs_put_super()) first.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

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

it's not needed anymore; we used to, back when we had to do
mount_subtree() by hand, complete with put_mnt_ns() in it.
No more...  Apparmor didn't need it since the __d_path() fix.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This is the last part of the patch series. It modifies the btrfs
code to use the integrity check module if configured to do so
with the define BTRFS_FS_CHECK_INTEGRITY. If this define is not set,
the only effective change is that code is added that handles the
mount option to activate the integrity check. If the mount option is
set and the define BTRFS_FS_CHECK_INTEGRITY is not set, that code
complains in the log and the mount fails with EINVAL.

Add the mount option to activate the usage of the integrity check
code.
Add invocation of btrfs integrity check code init and cleanup
function on mount and umount, respectively.
Add hook to call btrfs integrity check code version of
submit_bh/submit_bio.
Signed-off-by: NStefan Behrens <sbehrens@giantdisaster.de>

Now that we're properly keeping track of delayed inode space we've been getting
a lot of warnings out of btrfs_dirty_inode() when running xfstest 83.  This is
because a bunch of people call mark_inode_dirty, which is void so we can't
return ENOSPC.  This needs to be fixed in a few areas

1) file_update_time - this updates the mtime and such when writing to a file,
which will call mark_inode_dirty.  So copy file_update_time into btrfs so we can
call btrfs_dirty_inode directly and return an error if we get one appropriately.

2) fix symlinks to use btrfs_setattr for ->setattr.  For some reason we weren't
setting ->setattr for symlinks, even though we should have been.  This catches
one of the cases where we were getting errors in mark_inode_dirty.

3) Fix btrfs_setattr and btrfs_setsize to call btrfs_dirty_inode directly
instead of mark_inode_dirty.  This lets us return errors properly for truncate
and chown/anything related to setattr.

4) Add a new btrfs_fs_dirty_inode which will just call btrfs_dirty_inode and
print an error if we have one.  The only remaining user we can't control for
this is touch_atime(), but we don't really want to keep people from walking
down the tree if we don't have space to save the atime update, so just complain
but don't worry about it.

With this patch xfstests 83 complains a handful of times instead of hundreds of
times.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

When we use raid0 as the data profile, df command may show us a very
inaccurate value of the available space, which may be much less than the
real one. It may make the users puzzled. Fix it by changing the calculation
of the available space, and making it be more similar to a fake chunk
allocation.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

To reproduce this bug:

  # dd if=/dev/zero of=img bs=1M count=256
  # mkfs.btrfs img
  # losetup -r /dev/loop1 img
  # mount /dev/loop1 /mnt
  OOPS!!

It triggered BUG_ON(!nr_devices) in btrfs_calc_avail_data_space().

To fix this, instead of checking write-only devices, we check all open
deivces:

  # df -h /dev/loop1
  Filesystem            Size  Used Avail Use% Mounted on
  /dev/loop1            250M   28K  238M   1% /mnt
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>

takes vfsmount and relative path, does lookup within that vfsmount
(possibly triggering automounts) and returns the result as root
of subtree suitable for return by ->mount() (i.e. a reference to
dentry and an active reference to its superblock grabbed, superblock
locked exclusive).

btrfs and nfs switched to it instead of open-coding the sucker.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Life is much saner if create_mnt_ns(mnt) drops mnt in case of error...
Switch it to such calling conventions, switch callers, fix double mntput() in
fs/nfs/super.c one.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

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

Rename no_space_cache option to nospace_cache to be more consistent with
the rest, where the simple prefix 'no' is used to negate an option.

The option has been introduced during the -rc1 cycle and there are has not been
widely used, so it's safe.
Signed-off-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Commits 6c41761f and 45ea6095 introduced the possibility of NULL pointer
dereference on error paths, also we would leave all devices busy and
leak fs_info with all sub-structures on error when trying to mount an
already mounted fs to a different directory.

Fix this by doing all allocations before trying to open any of the
devices, adjust error path for mount-already-mounted-fs case.
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

btrfs_parse_early_options() can fail due to error while scanning devices
(-o device= option), but still strdup() subvol_name string:

mount -o subvol=SUBV,device=BAD_DEVICE <dev> <mnt>

So free subvol_name string on error.
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

Don't leak subvol_name string in case multiple subvol= options are
given.  "The lastest option is effective" behavior (consistent with
subvolid= and subvolrootid= options) is preserved.
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

On error path 'tree_root' is treed in 'free_fs_info()'.
No need to free it explicitely. Noticed by SLUB in debug mode:

Complete reproducer under usermode linux (discovered on real
machine):

    bdev=/dev/ubda
    btr_root=/btr
    /mkfs.btrfs $bdev
    mount $bdev $btr_root
    mkdir $btr_root/subvols/
    cd $btr_root/subvols/
    /btrfs su cr foo
    /btrfs su cr bar
    mount $bdev -osubvol=subvols/foo $btr_root/subvols/bar
    umount $btr_root/subvols/bar

which gives

device fsid 4d55aa28-45b1-474b-b4ec-da912322195e devid 1 transid 7 /dev/ubda
=============================================================================
BUG kmalloc-2048: Object already free
-----------------------------------------------------------------------------

INFO: Allocated in btrfs_mount+0x389/0x7f0 age=0 cpu=0 pid=277
INFO: Freed in btrfs_mount+0x51c/0x7f0 age=0 cpu=0 pid=277
INFO: Slab 0x0000000062886200 objects=15 used=9 fp=0x0000000070b4d2d0 flags=0x4081
INFO: Object 0x0000000070b4d2d0 @offset=21200 fp=0x0000000070b4a968
...
Call Trace:
70b31948:  [<6008c522>] print_trailer+0xe2/0x130
70b31978:  [<6008c5aa>] object_err+0x3a/0x50
70b319a8:  [<6008e242>] free_debug_processing+0x142/0x2a0
70b319e0:  [<600ebf6f>] btrfs_mount+0x55f/0x7f0
70b319f8:  [<6008e5c1>] __slab_free+0x221/0x2d0
Signed-off-by: NSergei Trofimovich <slyfox@gentoo.org>
Cc: Arne Jansen <sensille@gmx.net>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: David Sterba <dsterba@suse.cz>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

This takes some of the free space in the btrfs super block
to record information about most of the roots in the last four
commits.

It also adds a -o recovery to use the root history log when
we're not able to read the tree of tree roots, the extent
tree root, the device tree root or the csum root.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

fs_info has now ~9kb, more than fits into one page. This will cause
mount failure when memory is too fragmented. Top space consumers are
super block structures super_copy and super_for_commit, ~2.8kb each.
Allocate them dynamically. fs_info will be ~3.5kb. (measured on x86_64)

Add a wrapper for freeing fs_info and all of it's dynamically allocated
members.
Signed-off-by: NDavid Sterba <dsterba@suse.cz>

There's a missing test whether the path passed to subvol=path option
during mount is a real subvolume, allowing any directory located in
default subovlume to be passed and accepted for mount.

(current btrfs progs prevent this early)
$ btrfs subvol snapshot . p1-snap
ERROR: '.' is not a subvolume

(with "is subvolume?" test bypassed)
$ btrfs subvol snapshot . p1-snap
Create a snapshot of '.' in './p1-snap'

$ btrfs subvol list -p .
ID 258 parent 5 top level 5 path subvol
ID 259 parent 5 top level 5 path subvol1
ID 260 parent 5 top level 5 path default-subvol1
ID 262 parent 5 top level 5 path p1/p1-snapshot
ID 263 parent 259 top level 5 path subvol1/subvol1-snap

The problem I see is that this makes a false impression of snapshotting the
given subvolume but in fact snapshots the default one: a user expects outcome
like ID 263 but in fact gets ID 262 .

This patch makes mount fail with EINVAL with a message in syslog.
Signed-off-by: NDavid Sterba <dsterba@suse.cz>

Initialize fs_info->bdev_holder a bit earlier to be able to pass a
correct holder id to blkdev_get() when opening seed devices with O_EXCL.
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

Signed-off-by: NJie Liu <jeff.liu@oracle.com>

Some users have requested this and I've found I needed a way to disable cache
loading without actually clearing the cache, so introduce the no_space_cache
option.  Before we check the super blocks cache generation field and if it was
populated we always turned space caching on.  Now we check this and set the
space cache option on, and then parse the mount options so that if we want it
off it get's turned off.  Then we check the mount option all the places we do
the caching work instead of checking the super's cache generation.  This makes
things more consistent and lets us turn space caching off.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

We've only been able to mount with subvol=<whatever> where whatever was a subvol
within whatever root we had as the default.  This allows us to mount -o
subvol=path/to/subvol/you/want relative from the normal fs_tree root.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

Currently what we do is just wrong.  We either

1) Alloc a new "root" dentry with sb->s_root as it's parent which is just wrong
as we could walk into this subvol later on via another path and hilarity could
ensue.  Also we don't check the return value of d_splice_alias which isn't good
either.

or

2) Do a d_find_alias() which we could have lost our dentry from cache at this
point and found nothing.

So use d_obtain_alias().  In the case that we already have the inode/dentry in
cache we will get the correct dentry.  If not we will get a disconnected dentry
tree so if we walk into it later on everything will be connected up properly.
Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

There are three missed mount options settable by user which are not
currently displayed in mount output.
Signed-off-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

This makes the inode map cache default to off until we
fix the overflow problem when the free space crcs don't fit
inside a single page.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Caching "we have already removed suid/caps" was overenthusiastic as merged.
On network filesystems we might have had suid/caps set on another client,
silently picked by this client on revalidate, all of that *without* clearing
the S_NOSEC flag.

AFAICS, the only reasonably sane way to deal with that is
	* new superblock flag; unless set, S_NOSEC is not going to be set.
	* local block filesystems set it in their ->mount() (more accurately,
mount_bdev() does, so does btrfs ->mount(), users of mount_bdev() other than
local block ones clear it)
	* if any network filesystem (or a cluster one) wants to use S_NOSEC,
it'll need to set MS_NOSEC in sb->s_flags *AND* take care to clear S_NOSEC when
inode attribute changes are picked from other clients.

It's not an earth-shattering hole (anybody that can set suid on another client
will almost certainly be able to write to the file before doing that anyway),
but it's a bug that needs fixing.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This will detect small random writes into files and
queue the up for an auto defrag process.  It isn't well suited to
database workloads yet, but works for smaller files such as rpm, sqlite
or bdb databases.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

This sixth patch of eight in this cleancache series "opts-in"
cleancache for btrfs.  Filesystems must explicitly enable
cleancache by calling cleancache_init_fs anytime an instance
of the filesystem is mounted.  Btrfs uses its own readpage
which must be hooked, but all other cleancache hooks are in
the VFS layer including the matching cleancache_flush_fs hook
which must be called on unmount.

Details and a FAQ can be found in Documentation/vm/cleancache.txt

[v6-v8: no changes]
[v5: jeremy@goop.org: simplify init hook and any future fs init changes]
Signed-off-by: NDan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>
Reviewed-by: NJeremy Fitzhardinge <jeremy@goop.org>
Reviewed-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Rik Van Riel <riel@redhat.com>
Cc: Jan Beulich <JBeulich@novell.com>
Cc: Andreas Dilger <adilger@sun.com>
Cc: Ted Ts'o <tytso@mit.edu>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <joel.becker@oracle.com>
Cc: Nitin Gupta <ngupta@vflare.org>