djwong/linux forked from torvalds/linux

…laim

Reclaiming blocks allocated to an inode's CoW fork can happen as part of
inode reclamation, which in turn can be triggered by memory reclaim.
Therefore, we cannot let the transaction allocation recurse into fs
reclaim.  This manifests as lockdep warnings such as:

======================================================
WARNING: possible circular locking dependency detected
4.14.0-rc1 #1 Not tainted
------------------------------------------------------
xfs_scrub/1344 is trying to acquire lock:
 (fs_reclaim){+.+.}, at: [<ffffffff811b2b75>] fs_reclaim_acquire.part.75+0x5/0x30

but task is already holding lock:
 (sb_internal){.+.+}, at: [<ffffffffa015e65b>] xfs_trans_alloc+0xeb/0x130 [xfs]

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (sb_internal){.+.+}:
       lock_acquire+0xab/0x200
       __sb_start_write+0xbc/0x200
       xfs_trans_alloc+0xeb/0x130 [xfs]
       xfs_reflink_cancel_cow_range+0x8e/0x3d0 [xfs]
       xfs_fs_destroy_inode+0x22f/0x350 [xfs]
       dispose_list+0x48/0x70
       prune_icache_sb+0x42/0x50
       super_cache_scan+0x13b/0x190
       shrink_slab.constprop.79+0x212/0x5d0
       shrink_node+0x5f/0x190
       do_try_to_free_pages+0xd8/0x2d0
       try_to_free_pages+0xf1/0x370
       __alloc_pages_slowpath+0x445/0x10d0
       __alloc_pages_nodemask+0x2c4/0x340
       khugepaged+0xb38/0x2510
       kthread+0x148/0x180
       ret_from_fork+0x2a/0x40

-> #0 (fs_reclaim){+.+.}:
       __lock_acquire+0x10bf/0x1110
       lock_acquire+0xab/0x200
       fs_reclaim_acquire.part.75+0x29/0x30
       kmem_cache_alloc+0x29/0x2d0
       kmem_zone_alloc+0x83/0x100 [xfs]
       xfs_trans_alloc+0x68/0x130 [xfs]
       xfs_reflink_cancel_cow_range+0x8e/0x3d0 [xfs]
       xfs_fs_destroy_inode+0x22f/0x350 [xfs]
       xfs_bulkstat_one_int+0x262/0x480 [xfs]
       xfs_bulkstat_one+0x16/0x20 [xfs]
       xfs_bulkstat+0x4c5/0x6b0 [xfs]
       xfs_ioc_bulkstat+0xee/0x190 [xfs]
       xfs_file_ioctl+0x41b/0xd30 [xfs]
       do_vfs_ioctl+0x8f/0x6f0
       SyS_ioctl+0x3b/0x70
       entry_SYSCALL_64_fastpath+0x1f/0xbe

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

When we're scrubbing the realtime metadata, cross-reference
the rtrmapt.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

When we're checking the realtime rmapbt, cross-reference the entries
with the realtime bitmap too.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Check the realtime reverse mapping btree against the rtbitmap, and
modify the rtbitmap scrub to check against the rtrmapbt.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Connect the getfsmap ioctl to the realtime rmapbt.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Connect the map and unmap reverse-mapping operations to the realtime
rmapbt via the deferred operation callbacks.  This enables us to
perform rmap operations against the correct btree.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

The original rmap code assumed that there would always be at least
one rmap in the rmapbt (the AG sb/agf/agi) and so errored out if
it didn't find one.  This assumption isn't true for rtrmapbt, so
remove the check and just deal with the situation.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Plumb in the pieces we need to embed the root of the realtime rmap
btree in an inode's data fork, complete with new fork type and
on-disk interpretation functions.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Add a field to the superblock to record the rt rmapbt inode and load
it at mount time.  The rtrmapbt inode will have a unique extent format
code, which means that we also have to update the inode validation and
flush routines to look for it.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Identify rtrmapbt blocks in the log correctly so that we can
validate them during log recovery.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Extend the rmap update (RUI) log items with a new realtime flag that
indicates that the updates apply against the realtime rmapbt.  We'll
wire up the actual rmap code later.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Prepare the high-level rmap functions to deal with the new realtime
rmapbt and its slightly different conventions.  Provide the ability
to talk to either rmapbt or rtrmapbt formats from the same high
level code.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Implement the generic btree operations needed to manipulate rtrmap
btree blocks. This is different from the regular rmapbt in that we
allocate space from the filesystem at large, and are neither
constrained to the free space nor any particular AG.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Make sure that there's enough log reservation to handle mapping
and unmapping realtime extents.  We have to reserve enough space
to handle a split in the rtrmapbt to add the record and a second
split in the regular rmapbt to record the rtrmapbt split.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Start filling out the rtrmap btree implementation. Start with the
on-disk btree format; add everything needed to read, write and
manipulate rmap btree blocks. This prepares the way for connecting the
btree operations implementation.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Add new realtime rmap btree definitions. The realtime rmap btree will
be rooted from a hidden inode, but has its own shape and therefore
needs to have most of its own separate types.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Change the startblock and blockcount fields of xfs_refcount_irec to
be 64 bits wide.  This enables us to use the same high level rmap
code for either tree.  We'll also collect all the resulting breakage
fixes here.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Make it so that we can actually store btree records in the inode
core (i.e. enable bb_level == 0) so that the rtrmapbt can do this.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

For btrees that are rooted in the inode core, we have to have a
function to resize the root.  This is fairly specific to each
btree type, so make xfs_iroot_realloc a per-btree function.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Whenever we load a buffer, explicitly re-call the structure verifier to
ensure that memory isn't corrupting things.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Expose all metadata structure buffer verifier functions via buf_ops.
These will be used by the online scrub mechanism to look for problems
with buffers that are already sitting around in memory.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

If the xattr leaf block looks corrupt, return -EFSCORRUPTED to userspace
instead of ASSERTing on debug kernels or running off the end of the
buffer on regular kernels.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Replace the current haphazard dir2 shortform verifier callsites with a
centralized verifier function that can be called either with the default
verifier functions or with a custom set.  This helps us strengthen
integrity checking while providing us with flexibility for repair tools.

xfs_repair wants this to be able to supply its own verifier functions
when trying to fix possibly corrupt metadata.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Change the short form directory structure verifier function to return
the instruction pointer of a failing check or NULL if everything's ok.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Create a function to check the structure of short form symlink targets.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Create a function to perform structure verification for short form
extended attributes.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Consolidate the fork size and format verifiers to xfs_dinode_verify so
that we can reject bad inodes earlier and in a single place.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Move the v3 inode integrity information (crc, owner, metauuid) before we
look at anything else in the inode so that we don't waste time on a torn
write or a totally garbled block.  This makes xfs_dinode_verify more
consistent with the other verifiers.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Refactor the callers of verifiers to print the instruction address of a
failing check.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Modify each function that checks the contents of a metadata buffer to
return the instruction address of the failing test so that we can report
more precise failure errors to the log.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Since __xfs_dir3_data_check verifies on-disk metadata, we can't have it
noisily blowing asserts and hanging the system on corrupt data coming in
off the disk.  Instead, have it return a boolean like all the other
checker functions, and only have it noisily fail if we fail in debug
mode.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Create two helper functions to verify the headers of a long format
btree block.  We'll use this later for the realtime rmapbt.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Forward everything scrub whines about to dmesg.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Repair inconsistent symbolic link data.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>