1. 08 Apr, 2017 25 commits
    • Christoph Hellwig's avatar
      xfs: fix and streamline error handling in xfs_end_io · 87cdf91a
      Christoph Hellwig authored
      commit 787eb485 upstream.
      
      There are two different cases of buffered I/O errors:
      
       - first we can have an already shutdown fs.  In that case we should skip
         any on-disk operations and just clean up the appen transaction if
         present and destroy the ioend
       - a real I/O error.  In that case we should cleanup any lingering COW
         blocks.  This gets skipped in the current code and is fixed by this
         patch.
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Reviewed-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      87cdf91a
    • Christoph Hellwig's avatar
      xfs: only reclaim unwritten COW extents periodically · 1c0d974b
      Christoph Hellwig authored
      commit 3802a345 upstream.
      
      We only want to reclaim preallocations from our periodic work item.
      Currently this is archived by looking for a dirty inode, but that check
      is rather fragile.  Instead add a flag to xfs_reflink_cancel_cow_* so
      that the caller can ask for just cancelling unwritten extents in the COW
      fork.
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Reviewed-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      [darrick: fix typos in commit message]
      Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      1c0d974b
    • Christoph Hellwig's avatar
      xfs: tune down agno asserts in the bmap code · 5d834e1a
      Christoph Hellwig authored
      commit 410d17f6 upstream.
      
      In various places we currently assert that xfs_bmap_btalloc allocates
      from the same as the firstblock value passed in, unless it's either
      NULLAGNO or the dop_low flag is set.  But the reflink code does not
      fully follow this convention as it passes in firstblock purely as
      a hint for the allocator without actually having previous allocations
      in the transaction, and without having a minleft check on the current
      AG, leading to the assert firing on a very full and heavily used
      file system.  As even the reflink code only allocates from equal or
      higher AGs for now we can simply the check to always allow for equal
      or higher AGs.
      
      Note that we need to eventually split the two meanings of the firstblock
      value.  At that point we can also allow the reflink code to allocate
      from any AG instead of limiting it in any way.
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Reviewed-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      5d834e1a
    • Chandan Rajendra's avatar
      xfs: Use xfs_icluster_size_fsb() to calculate inode chunk alignment · 854a9bf0
      Chandan Rajendra authored
      commit 8ee9fdbe upstream.
      
      On a ppc64 system, executing generic/256 test with 32k block size gives the following call trace,
      
      XFS: Assertion failed: args->maxlen > 0, file: /root/repos/linux/fs/xfs/libxfs/xfs_alloc.c, line: 2026
      
      kernel BUG at /root/repos/linux/fs/xfs/xfs_message.c:113!
      Oops: Exception in kernel mode, sig: 5 [#1]
      SMP NR_CPUS=2048
      DEBUG_PAGEALLOC
      NUMA
      pSeries
      Modules linked in:
      CPU: 2 PID: 19361 Comm: mkdir Not tainted 4.10.0-rc5 #58
      task: c000000102606d80 task.stack: c0000001026b8000
      NIP: c0000000004ef798 LR: c0000000004ef798 CTR: c00000000082b290
      REGS: c0000001026bb090 TRAP: 0700   Not tainted  (4.10.0-rc5)
      MSR: 8000000000029032 <SF,EE,ME,IR,DR,RI>
      CR: 28004428  XER: 00000000
      CFAR: c0000000004ef180 SOFTE: 1
      GPR00: c0000000004ef798 c0000001026bb310 c000000001157300 ffffffffffffffea
      GPR04: 000000000000000a c0000001026bb130 0000000000000000 ffffffffffffffc0
      GPR08: 00000000000000d1 0000000000000021 00000000ffffffd1 c000000000dd4990
      GPR12: 0000000022004444 c00000000fe00800 0000000020000000 0000000000000000
      GPR16: 0000000000000000 0000000043a606fc 0000000043a76c08 0000000043a1b3d0
      GPR20: 000001002a35cd60 c0000001026bbb80 0000000000000000 0000000000000001
      GPR24: 0000000000000240 0000000000000004 c00000062dc55000 0000000000000000
      GPR28: 0000000000000004 c00000062ecd9200 0000000000000000 c0000001026bb6c0
      NIP [c0000000004ef798] .assfail+0x28/0x30
      LR [c0000000004ef798] .assfail+0x28/0x30
      Call Trace:
      [c0000001026bb310] [c0000000004ef798] .assfail+0x28/0x30 (unreliable)
      [c0000001026bb380] [c000000000455d74] .xfs_alloc_space_available+0x194/0x1b0
      [c0000001026bb410] [c00000000045b914] .xfs_alloc_fix_freelist+0x144/0x480
      [c0000001026bb580] [c00000000045c368] .xfs_alloc_vextent+0x698/0xa90
      [c0000001026bb650] [c0000000004a6200] .xfs_ialloc_ag_alloc+0x170/0x820
      [c0000001026bb7c0] [c0000000004a9098] .xfs_dialloc+0x158/0x320
      [c0000001026bb8a0] [c0000000004e628c] .xfs_ialloc+0x7c/0x610
      [c0000001026bb990] [c0000000004e8138] .xfs_dir_ialloc+0xa8/0x2f0
      [c0000001026bbaa0] [c0000000004e8814] .xfs_create+0x494/0x790
      [c0000001026bbbf0] [c0000000004e5ebc] .xfs_generic_create+0x2bc/0x410
      [c0000001026bbce0] [c0000000002b4a34] .vfs_mkdir+0x154/0x230
      [c0000001026bbd70] [c0000000002bc444] .SyS_mkdirat+0x94/0x120
      [c0000001026bbe30] [c00000000000b760] system_call+0x38/0xfc
      Instruction dump:
      4e800020 60000000 7c0802a6 7c862378 3c82ffca 7ca72b78 38841c18 7c651b78
      38600000 f8010010 f821ff91 4bfff94d <0fe00000> 60000000 7c0802a6 7c892378
      
      When block size is larger than inode cluster size, the call to
      XFS_B_TO_FSBT(mp, mp->m_inode_cluster_size) returns 0. Also, mkfs.xfs
      would have set xfs_sb->sb_inoalignmt to 0. This causes
      xfs_ialloc_cluster_alignment() to return 0.  Due to this
      args.minalignslop (in xfs_ialloc_ag_alloc()) gets the unsigned
      equivalent of -1 assigned to it. This later causes alloc_len in
      xfs_alloc_space_available() to have a value of 0. In such a scenario
      when args.total is also 0, the assert statement "ASSERT(args->maxlen >
      0);" fails.
      
      This commit fixes the bug by replacing the call to XFS_B_TO_FSBT() in
      xfs_ialloc_cluster_alignment() with a call to xfs_icluster_size_fsb().
      Suggested-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      Signed-off-by: default avatarChandan Rajendra <chandan@linux.vnet.ibm.com>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      Reviewed-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      854a9bf0
    • Brian Foster's avatar
      xfs: don't reserve blocks for right shift transactions · 8c1e9cfd
      Brian Foster authored
      commit 48af96ab upstream.
      
      The block reservation for the transaction allocated in
      xfs_shift_file_space() is an artifact of the original collapse range
      support. It exists to handle the case where a collapse range occurs,
      the initial extent is left shifted into a location that forms a
      contiguous boundary with the previous extent and thus the extents
      are merged. This code was subsequently refactored and reused for
      insert range (right shift) support.
      
      If an insert range occurs under low free space conditions, the
      extent at the starting offset is split before the first shift
      transaction is allocated. If the block reservation fails, this
      leaves separate, but contiguous extents around in the inode. While
      not a fatal problem, this is unexpected and will flag a warning on
      subsequent insert range operations on the inode. This problem has
      been reproduce intermittently by generic/270 running against a
      ramdisk device.
      
      Since right shift does not create new extent boundaries in the
      inode, a block reservation for extent merge is unnecessary. Update
      xfs_shift_file_space() to conditionally reserve fs blocks for left
      shift transactions only. This avoids the warning reproduced by
      generic/270.
      Reported-by: default avatarRoss Zwisler <ross.zwisler@linux.intel.com>
      Signed-off-by: default avatarBrian Foster <bfoster@redhat.com>
      Reviewed-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      8c1e9cfd
    • Darrick J. Wong's avatar
      xfs: fix uninitialized variable in _reflink_convert_cow · a3aca9b4
      Darrick J. Wong authored
      commit 93aaead5 upstream.
      
      Fix an uninitialize variable.
      Reported-by: default avatarDan Carpenter <dan.carpenter@oracle.com>
      Reviewed-by: default avatarBrian Foster <bfoster@redhat.com>
      Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      a3aca9b4
    • Brian Foster's avatar
      xfs: split indlen reservations fairly when under reserved · 1d7babf1
      Brian Foster authored
      commit 75d65361 upstream.
      
      Certain workoads that punch holes into speculative preallocation can
      cause delalloc indirect reservation splits when the delalloc extent is
      split in two. If further splits occur, an already short-handed extent
      can be split into two in a manner that leaves zero indirect blocks for
      one of the two new extents. This occurs because the shortage is large
      enough that the xfs_bmap_split_indlen() algorithm completely drains the
      requested indlen of one of the extents before it honors the existing
      reservation.
      
      This ultimately results in a warning from xfs_bmap_del_extent(). This
      has been observed during file copies of large, sparse files using 'cp
      --sparse=always.'
      
      To avoid this problem, update xfs_bmap_split_indlen() to explicitly
      apply the reservation shortage fairly between both extents. This smooths
      out the overall indlen shortage and defers the situation where we end up
      with a delalloc extent with zero indlen reservation to extreme
      circumstances.
      Reported-by: default avatarPatrick Dung <mpatdung@gmail.com>
      Signed-off-by: default avatarBrian Foster <bfoster@redhat.com>
      Reviewed-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      1d7babf1
    • Brian Foster's avatar
      xfs: handle indlen shortage on delalloc extent merge · 17722773
      Brian Foster authored
      commit 0e339ef8 upstream.
      
      When a delalloc extent is created, it can be merged with pre-existing,
      contiguous, delalloc extents. When this occurs,
      xfs_bmap_add_extent_hole_delay() merges the extents along with the
      associated indirect block reservations. The expectation here is that the
      combined worst case indlen reservation is always less than or equal to
      the indlen reservation for the individual extents.
      
      This is not always the case, however, as existing extents can less than
      the expected indlen reservation if the extent was previously split due
      to a hole punch. If a new extent merges with such an extent, the total
      indlen requirement may be larger than the sum of the indlen reservations
      held by both extents.
      
      xfs_bmap_add_extent_hole_delay() assumes that the worst case indlen
      reservation is always available and assigns it to the merged extent
      without consideration for the indlen held by the pre-existing extent. As
      a result, the subsequent xfs_mod_fdblocks() call can attempt an
      unintentional allocation rather than a free (indicated by an ASSERT()
      failure). Further, if the allocation happens to fail in this context,
      the failure goes unhandled and creates a filesystem wide block
      accounting inconsistency.
      
      Fix xfs_bmap_add_extent_hole_delay() to function as designed. Cap the
      indlen reservation assigned to the merged extent to the sum of the
      indlen reservations held by each of the individual extents.
      Signed-off-by: default avatarBrian Foster <bfoster@redhat.com>
      Reviewed-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      17722773
    • Christoph Hellwig's avatar
      xfs: don't fail xfs_extent_busy allocation · 0b20c0af
      Christoph Hellwig authored
      commit 5e30c23d upstream.
      
      We don't just need the structure to track busy extents which can be
      avoided with a synchronous transaction, but also to keep track of
      pending discard.
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Reviewed-by: default avatarBrian Foster <bfoster@redhat.com>
      Reviewed-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      0b20c0af
    • Bill O'Donnell's avatar
      xfs: correct null checks and error processing in xfs_initialize_perag · e8eb2c06
      Bill O'Donnell authored
      commit b20fe473 upstream.
      
      If pag cannot be allocated, the current error exit path will trip
      a null pointer deference error when calling xfs_buf_hash_destroy
      with a null pag.  Fix this by adding a new error exit labels and
      jumping to those accordingly, avoiding the hash destroy and
      unnecessary kmem_free on pag.
      
      Up to three things need to be properly unwound:
      
      1) pag memory allocation
      2) xfs_buf_hash_init
      3) radix_tree_insert
      
      For any given iteration through the loop, any of the above which
      succeed must be unwound for /this/ pag, and then all prior
      initialized pags must be unwound.
      
      Addresses-Coverity-Id: 1397628 ("Dereference after null check")
      Reported-by: default avatarColin Ian King <colin.king@canonical.com>
      Signed-off-by: default avatarBill O'Donnell <billodo@redhat.com>
      Reviewed-by: default avatarEric Sandeen <sandeen@redhat.com>
      Reviewed-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      e8eb2c06
    • Christoph Hellwig's avatar
      xfs: update ctime and mtime on clone destinatation inodes · 304ec448
      Christoph Hellwig authored
      commit c5ecb423 upstream.
      
      We're changing both metadata and data, so we need to update the
      timestamps for clone operations.  Dedupe on the other hand does
      not change file data, and only changes invisible metadata so the
      timestamps should not be updated.
      
      This follows existing btrfs behavior.
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Reviewed-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      [darrick: remove redundant is_dedupe test]
      Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      304ec448
    • Christoph Hellwig's avatar
      xfs: reject all unaligned direct writes to reflinked files · 900c499d
      Christoph Hellwig authored
      commit 54a4ef8a upstream.
      
      We currently fall back from direct to buffered writes if we detect a
      remaining shared extent in the iomap_begin callback.  But by the time
      iomap_begin is called for the potentially unaligned end block we might
      have already written most of the data to disk, which we'd now write
      again using buffered I/O.  To avoid this reject all writes to reflinked
      files before starting I/O so that we are guaranteed to only write the
      data once.
      
      The alternative would be to unshare the unaligned start and/or end block
      before doing the I/O. I think that's doable, and will actually be
      required to support reflinks on DAX file system.  But it will take a
      little more time and I'd rather get rid of the double write ASAP.
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Reviewed-by: default avatarBrian Foster <bfoster@redhat.com>
      Reviewed-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      900c499d
    • Hou Tao's avatar
      xfs: reset b_first_retry_time when clear the retry status of xfs_buf_t · 17c17805
      Hou Tao authored
      commit 4dd2eb63 upstream.
      
      After successful IO or permanent error, b_first_retry_time also
      needs to be cleared, else the invalid first retry time will be
      used by the next retry check.
      Signed-off-by: default avatarHou Tao <houtao1@huawei.com>
      Reviewed-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      17c17805
    • Darrick J. Wong's avatar
      xfs: mark speculative prealloc CoW fork extents unwritten · b0f88f0d
      Darrick J. Wong authored
      commit 5eda4300 upstream.
      
      Christoph Hellwig pointed out that there's a potentially nasty race when
      performing simultaneous nearby directio cow writes:
      
      "Thread 1 writes a range from B to c
      
      "                    B --------- C
                                 p
      
      "a little later thread 2 writes from A to B
      
      "        A --------- B
                     p
      
      [editor's note: the 'p' denote cowextsize boundaries, which I added to
      make this more clear]
      
      "but the code preallocates beyond B into the range where thread
      "1 has just written, but ->end_io hasn't been called yet.
      "But once ->end_io is called thread 2 has already allocated
      "up to the extent size hint into the write range of thread 1,
      "so the end_io handler will splice the unintialized blocks from
      "that preallocation back into the file right after B."
      
      We can avoid this race by ensuring that thread 1 cannot accidentally
      remap the blocks that thread 2 allocated (as part of speculative
      preallocation) as part of t2's write preparation in t1's end_io handler.
      The way we make this happen is by taking advantage of the unwritten
      extent flag as an intermediate step.
      
      Recall that when we begin the process of writing data to shared blocks,
      we create a delayed allocation extent in the CoW fork:
      
      D: --RRRRRRSSSRRRRRRRR---
      C: ------DDDDDDD---------
      
      When a thread prepares to CoW some dirty data out to disk, it will now
      convert the delalloc reservation into an /unwritten/ allocated extent in
      the cow fork.  The da conversion code tries to opportunistically
      allocate as much of a (speculatively prealloc'd) extent as possible, so
      we may end up allocating a larger extent than we're actually writing
      out:
      
      D: --RRRRRRSSSRRRRRRRR---
      U: ------UUUUUUU---------
      
      Next, we convert only the part of the extent that we're actively
      planning to write to normal (i.e. not unwritten) status:
      
      D: --RRRRRRSSSRRRRRRRR---
      U: ------UURRUUU---------
      
      If the write succeeds, the end_cow function will now scan the relevant
      range of the CoW fork for real extents and remap only the real extents
      into the data fork:
      
      D: --RRRRRRRRSRRRRRRRR---
      U: ------UU--UUU---------
      
      This ensures that we never obliterate valid data fork extents with
      unwritten blocks from the CoW fork.
      Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      b0f88f0d
    • Darrick J. Wong's avatar
      xfs: allow unwritten extents in the CoW fork · a0c46fae
      Darrick J. Wong authored
      commit 05a630d7 upstream.
      
      In the data fork, we only allow extents to perform the following state
      transitions:
      
      delay -> real <-> unwritten
      
      There's no way to move directly from a delalloc reservation to an
      /unwritten/ allocated extent.  However, for the CoW fork we want to be
      able to do the following to each extent:
      
      delalloc -> unwritten -> written -> remapped to data fork
      
      This will help us to avoid a race in the speculative CoW preallocation
      code between a first thread that is allocating a CoW extent and a second
      thread that is remapping part of a file after a write.  In order to do
      this, however, we need two things: first, we have to be able to
      transition from da to unwritten, and second the function that converts
      between real and unwritten has to be made aware of the cow fork.  Do
      both of those things.
      Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      a0c46fae
    • Darrick J. Wong's avatar
      xfs: verify free block header fields · 1dc0e72c
      Darrick J. Wong authored
      commit de14c5f5 upstream.
      
      Perform basic sanity checking of the directory free block header
      fields so that we avoid hanging the system on invalid data.
      
      (Granted that just means that now we shutdown on directory write,
      but that seems better than hanging...)
      Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      1dc0e72c
    • Darrick J. Wong's avatar
      xfs: check for obviously bad level values in the bmbt root · 58565508
      Darrick J. Wong authored
      commit b3bf607d upstream.
      
      We can't handle a bmbt that's taller than BTREE_MAXLEVELS, and there's
      no such thing as a zero-level bmbt (for that we have extents format),
      so if we see this, send back an error code.
      Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      58565508
    • Darrick J. Wong's avatar
      xfs: filter out obviously bad btree pointers · 2b9dcb94
      Darrick J. Wong authored
      commit d5a91bae upstream.
      
      Don't let anybody load an obviously bad btree pointer.  Since the values
      come from disk, we must return an error, not just ASSERT.
      Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      Reviewed-by: default avatarEric Sandeen <sandeen@redhat.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      2b9dcb94
    • Darrick J. Wong's avatar
      xfs: fail _dir_open when readahead fails · cb308466
      Darrick J. Wong authored
      commit 7a652bbe upstream.
      
      When we open a directory, we try to readahead block 0 of the directory
      on the assumption that we're going to need it soon.  If the bmbt is
      corrupt, the directory will never be usable and the readahead fails
      immediately, so we might as well prevent the directory from being opened
      at all.  This prevents a subsequent read or modify operation from
      hitting it and taking the fs offline.
      
      NOTE: We're only checking for early failures in the block mapping, not
      the readahead directory block itself.
      Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      Reviewed-by: default avatarEric Sandeen <sandeen@redhat.com>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      cb308466
    • Darrick J. Wong's avatar
      xfs: fix toctou race when locking an inode to access the data map · 8059f061
      Darrick J. Wong authored
      commit 4b5bd5bf upstream.
      
      We use di_format and if_flags to decide whether we're grabbing the ilock
      in btree mode (btree extents not loaded) or shared mode (anything else),
      but the state of those fields can be changed by other threads that are
      also trying to load the btree extents -- IFEXTENTS gets set before the
      _bmap_read_extents call and cleared if it fails.
      
      We don't actually need to have IFEXTENTS set until after the bmbt
      records are successfully loaded and validated, which will fix the race
      between multiple threads trying to read the same directory.  The next
      patch strengthens directory bmbt validation by refusing to open the
      directory if reading the bmbt to start directory readahead fails.
      Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      8059f061
    • Brian Foster's avatar
      xfs: fix eofblocks race with file extending async dio writes · 02577091
      Brian Foster authored
      commit e4229d6b upstream.
      
      It's possible for post-eof blocks to end up being used for direct I/O
      writes. dio write performs an upfront unwritten extent allocation, sends
      the dio and then updates the inode size (if necessary) on write
      completion. If a file release occurs while a file extending dio write is
      in flight, it is possible to mistake the post-eof blocks for speculative
      preallocation and incorrectly truncate them from the inode. This means
      that the resulting dio write completion can discover a hole and allocate
      new blocks rather than perform unwritten extent conversion.
      
      This requires a strange mix of I/O and is thus not likely to reproduce
      in real world workloads. It is intermittently reproduced by generic/299.
      The error manifests as an assert failure due to transaction overrun
      because the aforementioned write completion transaction has only
      reserved enough blocks for btree operations:
      
        XFS: Assertion failed: tp->t_blk_res_used <= tp->t_blk_res, \
         file: fs/xfs//xfs_trans.c, line: 309
      
      The root cause is that xfs_free_eofblocks() uses i_size to truncate
      post-eof blocks from the inode, but async, file extending direct writes
      do not update i_size until write completion, long after inode locks are
      dropped. Therefore, xfs_free_eofblocks() effectively truncates the inode
      to the incorrect size.
      
      Update xfs_free_eofblocks() to serialize against dio similar to how
      extending writes are serialized against i_size updates before post-eof
      block zeroing. Specifically, wait on dio while under the iolock. This
      ensures that dio write completions have updated i_size before post-eof
      blocks are processed.
      Signed-off-by: default avatarBrian Foster <bfoster@redhat.com>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      Reviewed-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      02577091
    • Brian Foster's avatar
      xfs: sync eofblocks scans under iolock are livelock prone · 696bfc8e
      Brian Foster authored
      commit c3155097 upstream.
      
      The xfs_eofblocks.eof_scan_owner field is an internal field to
      facilitate invoking eofb scans from the kernel while under the iolock.
      This is necessary because the eofb scan acquires the iolock of each
      inode. Synchronous scans are invoked on certain buffered write failures
      while under iolock. In such cases, the scan owner indicates that the
      context for the scan already owns the particular iolock and prevents a
      double lock deadlock.
      
      eofblocks scans while under iolock are still livelock prone in the event
      of multiple parallel scans, however. If multiple buffered writes to
      different inodes fail and invoke eofblocks scans at the same time, each
      scan avoids a deadlock with its own inode by virtue of the
      eof_scan_owner field, but will never be able to acquire the iolock of
      the inode from the parallel scan. Because the low free space scans are
      invoked with SYNC_WAIT, the scan will not return until it has processed
      every tagged inode and thus both scans will spin indefinitely on the
      iolock being held across the opposite scan. This problem can be
      reproduced reliably by generic/224 on systems with higher cpu counts
      (x16).
      
      To avoid this problem, simplify the semantics of eofblocks scans to
      never invoke a scan while under iolock. This means that the buffered
      write context must drop the iolock before the scan. It must reacquire
      the lock before the write retry and also repeat the initial write
      checks, as the original state might no longer be valid once the iolock
      was dropped.
      Signed-off-by: default avatarBrian Foster <bfoster@redhat.com>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      Reviewed-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      696bfc8e
    • Brian Foster's avatar
      xfs: pull up iolock from xfs_free_eofblocks() · ff4ea420
      Brian Foster authored
      commit a36b9261 upstream.
      
      xfs_free_eofblocks() requires the IOLOCK_EXCL lock, but is called from
      different contexts where the lock may or may not be held. The
      need_iolock parameter exists for this reason, to indicate whether
      xfs_free_eofblocks() must acquire the iolock itself before it can
      proceed.
      
      This is ugly and confusing. Simplify the semantics of
      xfs_free_eofblocks() to require the caller to acquire the iolock
      appropriately and kill the need_iolock parameter. While here, the mp
      param can be removed as well as the xfs_mount is accessible from the
      xfs_inode structure. This patch does not change behavior.
      Signed-off-by: default avatarBrian Foster <bfoster@redhat.com>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      Reviewed-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      ff4ea420
    • Ladi Prosek's avatar
      KVM: nVMX: fix nested EPT detection · 3eb24329
      Ladi Prosek authored
      commit 7ad658b6 upstream.
      
      The nested_ept_enabled flag introduced in commit 7ca29de2 was not
      computed correctly. We are interested only in L1's EPT state, not the
      the combined L0+L1 value.
      
      In particular, if L0 uses EPT but L1 does not, nested_ept_enabled must
      be false to make sure that PDPSTRs are loaded based on CR3 as usual,
      because the special case described in 26.3.2.4 Loading Page-Directory-
      Pointer-Table Entries does not apply.
      
      Fixes: 7ca29de2 ("KVM: nVMX: fix CR3 load if L2 uses PAE paging and EPT")
      Cc: qemu-stable@nongnu.org
      Reported-by: default avatarWanpeng Li <wanpeng.li@hotmail.com>
      Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
      Signed-off-by: default avatarLadi Prosek <lprosek@redhat.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      3eb24329
    • Ilya Dryomov's avatar
      libceph: force GFP_NOIO for socket allocations · 8a7eb087
      Ilya Dryomov authored
      commit 633ee407 upstream.
      
      sock_alloc_inode() allocates socket+inode and socket_wq with
      GFP_KERNEL, which is not allowed on the writeback path:
      
          Workqueue: ceph-msgr con_work [libceph]
          ffff8810871cb018 0000000000000046 0000000000000000 ffff881085d40000
          0000000000012b00 ffff881025cad428 ffff8810871cbfd8 0000000000012b00
          ffff880102fc1000 ffff881085d40000 ffff8810871cb038 ffff8810871cb148
          Call Trace:
          [<ffffffff816dd629>] schedule+0x29/0x70
          [<ffffffff816e066d>] schedule_timeout+0x1bd/0x200
          [<ffffffff81093ffc>] ? ttwu_do_wakeup+0x2c/0x120
          [<ffffffff81094266>] ? ttwu_do_activate.constprop.135+0x66/0x70
          [<ffffffff816deb5f>] wait_for_completion+0xbf/0x180
          [<ffffffff81097cd0>] ? try_to_wake_up+0x390/0x390
          [<ffffffff81086335>] flush_work+0x165/0x250
          [<ffffffff81082940>] ? worker_detach_from_pool+0xd0/0xd0
          [<ffffffffa03b65b1>] xlog_cil_force_lsn+0x81/0x200 [xfs]
          [<ffffffff816d6b42>] ? __slab_free+0xee/0x234
          [<ffffffffa03b4b1d>] _xfs_log_force_lsn+0x4d/0x2c0 [xfs]
          [<ffffffff811adc1e>] ? lookup_page_cgroup_used+0xe/0x30
          [<ffffffffa039a723>] ? xfs_reclaim_inode+0xa3/0x330 [xfs]
          [<ffffffffa03b4dcf>] xfs_log_force_lsn+0x3f/0xf0 [xfs]
          [<ffffffffa039a723>] ? xfs_reclaim_inode+0xa3/0x330 [xfs]
          [<ffffffffa03a62c6>] xfs_iunpin_wait+0xc6/0x1a0 [xfs]
          [<ffffffff810aa250>] ? wake_atomic_t_function+0x40/0x40
          [<ffffffffa039a723>] xfs_reclaim_inode+0xa3/0x330 [xfs]
          [<ffffffffa039ac07>] xfs_reclaim_inodes_ag+0x257/0x3d0 [xfs]
          [<ffffffffa039bb13>] xfs_reclaim_inodes_nr+0x33/0x40 [xfs]
          [<ffffffffa03ab745>] xfs_fs_free_cached_objects+0x15/0x20 [xfs]
          [<ffffffff811c0c18>] super_cache_scan+0x178/0x180
          [<ffffffff8115912e>] shrink_slab_node+0x14e/0x340
          [<ffffffff811afc3b>] ? mem_cgroup_iter+0x16b/0x450
          [<ffffffff8115af70>] shrink_slab+0x100/0x140
          [<ffffffff8115e425>] do_try_to_free_pages+0x335/0x490
          [<ffffffff8115e7f9>] try_to_free_pages+0xb9/0x1f0
          [<ffffffff816d56e4>] ? __alloc_pages_direct_compact+0x69/0x1be
          [<ffffffff81150cba>] __alloc_pages_nodemask+0x69a/0xb40
          [<ffffffff8119743e>] alloc_pages_current+0x9e/0x110
          [<ffffffff811a0ac5>] new_slab+0x2c5/0x390
          [<ffffffff816d71c4>] __slab_alloc+0x33b/0x459
          [<ffffffff815b906d>] ? sock_alloc_inode+0x2d/0xd0
          [<ffffffff8164bda1>] ? inet_sendmsg+0x71/0xc0
          [<ffffffff815b906d>] ? sock_alloc_inode+0x2d/0xd0
          [<ffffffff811a21f2>] kmem_cache_alloc+0x1a2/0x1b0
          [<ffffffff815b906d>] sock_alloc_inode+0x2d/0xd0
          [<ffffffff811d8566>] alloc_inode+0x26/0xa0
          [<ffffffff811da04a>] new_inode_pseudo+0x1a/0x70
          [<ffffffff815b933e>] sock_alloc+0x1e/0x80
          [<ffffffff815ba855>] __sock_create+0x95/0x220
          [<ffffffff815baa04>] sock_create_kern+0x24/0x30
          [<ffffffffa04794d9>] con_work+0xef9/0x2050 [libceph]
          [<ffffffffa04aa9ec>] ? rbd_img_request_submit+0x4c/0x60 [rbd]
          [<ffffffff81084c19>] process_one_work+0x159/0x4f0
          [<ffffffff8108561b>] worker_thread+0x11b/0x530
          [<ffffffff81085500>] ? create_worker+0x1d0/0x1d0
          [<ffffffff8108b6f9>] kthread+0xc9/0xe0
          [<ffffffff8108b630>] ? flush_kthread_worker+0x90/0x90
          [<ffffffff816e1b98>] ret_from_fork+0x58/0x90
          [<ffffffff8108b630>] ? flush_kthread_worker+0x90/0x90
      
      Use memalloc_noio_{save,restore}() to temporarily force GFP_NOIO here.
      
      Link: http://tracker.ceph.com/issues/19309Reported-by: default avatarSergey Jerusalimov <wintchester@gmail.com>
      Signed-off-by: default avatarIlya Dryomov <idryomov@gmail.com>
      Reviewed-by: default avatarJeff Layton <jlayton@redhat.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      8a7eb087
  2. 31 Mar, 2017 15 commits