linux.git/fs/xfs, branch v3.18

xfs: track bulkstat progress by agino

2014-11-06T21:33:52+00:00

The bulkstat main loop progress is tracked by the "lastino"
variable, which is a full 64 bit inode. However, the loop actually
works on agno/agino pairs, and so there's a significant disconnect
between the rest of the loop and the main cursor. Convert this to
use the agino, and pass the agino into the chunk formatting function
and convert it too.

This gets rid of the inconsistency in the loop processing, and
finally makes it simple for us to skip inodes at any point in the
loop simply by incrementing the agino cursor.

cc:  # 3.17
Signed-off-by: Dave Chinner 
Reviewed-by: Brian Foster 
Signed-off-by: Dave Chinner

xfs: bulkstat error handling is broken

2014-11-06T21:31:15+00:00

The error propagation is a horror - xfs_bulkstat() returns
a rval variable which is only set if there are formatter errors. Any
sort of btree walk error or corruption will cause the bulkstat walk
to terminate but will not pass an error back to userspace. Worse
is the fact that formatter errors will also be ignored if any inodes
were correctly formatted into the user buffer.

Hence bulkstat can fail badly yet still report success to userspace.
This causes significant issues with xfsdump not dumping everything
in the filesystem yet reporting success. It's not until a restore
fails that there is any indication that the dump was bad and tha
bulkstat failed. This patch now triggers xfsdump to fail with
bulkstat errors rather than silently missing files in the dump.

This now causes bulkstat to fail when the lastino cookie does not
fall inside an existing inode chunk. The pre-3.17 code tolerated
that error by allowing the code to move to the next inode chunk
as the agino target is guaranteed to fall into the next btree
record.

With the fixes up to this point in the series, xfsdump now passes on
the troublesome filesystem image that exposes all these bugs.

cc: 
Signed-off-by: Dave Chinner 
Reviewed-by: Brian Foster

xfs: bulkstat main loop logic is a mess

2014-11-06T21:31:13+00:00

There are a bunch of variables tha tare more wildy scoped than they
need to be, obfuscated user buffer checks and tortured "next inode"
tracking. This all needs cleaning up to expose the real issues that
need fixing.

cc:  # 3.17
Signed-off-by: Dave Chinner 
Reviewed-by: Brian Foster 
Signed-off-by: Dave Chinner

xfs: bulkstat chunk-formatter has issues

2014-11-06T21:30:58+00:00

The loop construct has issues:
	- clustidx is completely unused, so remove it.
	- the loop tries to be smart by terminating when the
	  "freecount" tells it that all inodes are free. Just drop
	  it as in most cases we have to scan all inodes in the
	  chunk anyway.
	- move the "user buffer left" condition check to the only
	  point where we consume space int eh user buffer.
	- move the initialisation of agino out of the loop, leaving
	  just a simple loop control logic using the clusteridx.

Also, double handling of the user buffer variables leads to problems
tracking the current state - use the cursor variables directly
rather than keeping local copies and then having to update the
cursor before returning.

cc:  # 3.17
Signed-off-by: Dave Chinner 
Reviewed-by: Brian Foster 
Signed-off-by: Dave Chinner

xfs: bulkstat chunk formatting cursor is broken

2014-11-06T21:30:30+00:00

The xfs_bulkstat_agichunk formatting cursor takes buffer values from
the main loop and passes them via the structure to the chunk
formatter, and the writes the changed values back into the main loop
local variables. Unfortunately, this complex dance is full of corner
cases that aren't handled correctly.

The biggest problem is that it is double handling the information in
both the main loop and the chunk formatting function, leading to
inconsistent updates and endless loops where progress is not made.

To fix this, push the struct xfs_bulkstat_agichunk outwards to be
the primary holder of user buffer information. this removes the
double handling in the main loop.

Also, pass the last inode processed by the chunk formatter as a
separate parameter as it purely an output variable and is not
related to the user buffer consumption cursor.

Finally, the chunk formatting code is not shared by anyone, so make
it local to xfs_itable.c.

cc:  # 3.17
Signed-off-by: Dave Chinner 
Reviewed-by: Brian Foster 
Signed-off-by: Dave Chinner

xfs: bulkstat btree walk doesn't terminate

2014-11-06T21:29:57+00:00

The bulkstat code has several different ways of detecting the end of
an AG when doing a walk. They are not consistently detected, and the
code that checks for the end of AG conditions is not consistently
coded. Hence the are conditions where the walk code can get stuck in
an endless loop making no progress and not triggering any
termination conditions.

Convert all the "tmp/i" status return codes from btree operations
to a common name (stat) and apply end-of-ag detection to these
operations consistently.

cc:  # 3.17
Signed-off-by: Dave Chinner 
Reviewed-by: Brian Foster 
Signed-off-by: Dave Chinner

xfs: rework zero range to prevent invalid i_size updates

2014-10-29T23:35:11+00:00

The zero range operation is analogous to fallocate with the exception of
converting the range to zeroes. E.g., it attempts to allocate zeroed
blocks over the range specified by the caller. The XFS implementation
kills all delalloc blocks currently over the aligned range, converts the
range to allocated zero blocks (unwritten extents) and handles the
partial pages at the ends of the range by sending writes through the
pagecache.

The current implementation suffers from several problems associated with
inode size. If the aligned range covers an extending I/O, said I/O is
discarded and an inode size update from a previous write never makes it
to disk. Further, if an unaligned zero range extends beyond eof, the
page write induced for the partial end page can itself increase the
inode size, even if the zero range request is not supposed to update
i_size (via KEEP_SIZE, similar to an fallocate beyond EOF).

The latter behavior not only incorrectly increases the inode size, but
can lead to stray delalloc blocks on the inode. Typically, post-eof
preallocation blocks are either truncated on release or inode eviction
or explicitly written to by xfs_zero_eof() on natural file size
extension. If the inode size increases due to zero range, however,
associated blocks leak into the address space having never been
converted or mapped to pagecache pages. A direct I/O to such an
uncovered range cannot convert the extent via writeback and will BUG().
For example:

$ xfs_io -fc "pwrite 0 128k" -c "fzero -k 1m 54321" 
...
$ xfs_io -d -c "pread 128k 128k" 


If the entire delalloc extent happens to not have page coverage
whatsoever (e.g., delalloc conversion couldn't find a large enough free
space extent), even a full file writeback won't convert what's left of
the extent and we'll assert on inode eviction.

Rework xfs_zero_file_space() to avoid buffered I/O for partial pages.
Use the existing hole punch and prealloc mechanisms as primitives for
zero range. This implementation is not efficient nor ideal as we
writeback dirty data over the range and remove existing extents rather
than convert to unwrittern. The former writeback, however, is currently
the only mechanism available to ensure consistency between pagecache and
extent state. Even a pagecache truncate/delalloc punch prior to hole
punch has lead to inconsistencies due to racing with writeback.

This provides a consistent, correct implementation of zero range that
survives fsstress/fsx testing without assert failures. The
implementation can be optimized from this point forward once the
fundamental issue of pagecache and delalloc extent state consistency is
addressed.

Signed-off-by: Brian Foster 
Reviewed-by: Dave Chinner 
Signed-off-by: Dave Chinner

xfs: Check error during inode btree iteration in xfs_bulkstat()

2014-10-29T23:34:52+00:00

xfs_bulkstat() doesn't check error return from xfs_btree_increment(). In
case of specific fs corruption that could result in xfs_bulkstat()
entering an infinite loop because we would be looping over the same
chunk over and over again. Fix the problem by checking the return value
and terminating the loop properly.

Coverity-id: 1231338
cc: 
Signed-off-by: Jan Kara 
Reviewed-by: Jie Liu 
Signed-off-by: Dave Chinner

xfs: bulkstat doesn't release AGI buffer on error

2014-10-28T21:22:18+00:00

The recent refactoring of the bulkstat code left a small landmine in
the code. If a inobt read fails, then the tree walk is aborted and
returns without releasing the AGI buffer or freeing the cursor. This
can lead to a subsequent bulkstat call hanging trying to grab the
AGI buffer again.

cc: 
Signed-off-by: Dave Chinner 
Reviewed-by: Brian Foster 
Reviewed-by: Eric Sandeen 
Signed-off-by: Dave Chinner

Merge branch 'for-3.18/core' of git://git.kernel.dk/linux-block

2014-10-18T18:53:51+00:00

Pull core block layer changes from Jens Axboe:
 "This is the core block IO pull request for 3.18.  Apart from the new
  and improved flush machinery for blk-mq, this is all mostly bug fixes
  and cleanups.

   - blk-mq timeout updates and fixes from Christoph.

   - Removal of REQ_END, also from Christoph.  We pass it through the
     ->queue_rq() hook for blk-mq instead, freeing up one of the request
     bits.  The space was overly tight on 32-bit, so Martin also killed
     REQ_KERNEL since it's no longer used.

   - blk integrity updates and fixes from Martin and Gu Zheng.

   - Update to the flush machinery for blk-mq from Ming Lei.  Now we
     have a per hardware context flush request, which both cleans up the
     code should scale better for flush intensive workloads on blk-mq.

   - Improve the error printing, from Rob Elliott.

   - Backing device improvements and cleanups from Tejun.

   - Fixup of a misplaced rq_complete() tracepoint from Hannes.

   - Make blk_get_request() return error pointers, fixing up issues
     where we NULL deref when a device goes bad or missing.  From Joe
     Lawrence.

   - Prep work for drastically reducing the memory consumption of dm
     devices from Junichi Nomura.  This allows creating clone bio sets
     without preallocating a lot of memory.

   - Fix a blk-mq hang on certain combinations of queue depths and
     hardware queues from me.

   - Limit memory consumption for blk-mq devices for crash dump
     scenarios and drivers that use crazy high depths (certain SCSI
     shared tag setups).  We now just use a single queue and limited
     depth for that"

* 'for-3.18/core' of git://git.kernel.dk/linux-block: (58 commits)
  block: Remove REQ_KERNEL
  blk-mq: allocate cpumask on the home node
  bio-integrity: remove the needless fail handle of bip_slab creating
  block: include func name in __get_request prints
  block: make blk_update_request print prefix match ratelimited prefix
  blk-merge: don't compute bi_phys_segments from bi_vcnt for cloned bio
  block: fix alignment_offset math that assumes io_min is a power-of-2
  blk-mq: Make bt_clear_tag() easier to read
  blk-mq: fix potential hang if rolling wakeup depth is too high
  block: add bioset_create_nobvec()
  block: use bio_clone_fast() in blk_rq_prep_clone()
  block: misplaced rq_complete tracepoint
  sd: Honor block layer integrity handling flags
  block: Replace strnicmp with strncasecmp
  block: Add T10 Protection Information functions
  block: Don't merge requests if integrity flags differ
  block: Integrity checksum flag
  block: Relocate bio integrity flags
  block: Add a disk flag to block integrity profile
  block: Add prefix to block integrity profile flags
  ...