Commit Graph

67244 Commits

Author SHA1 Message Date
Linus Torvalds
9c75b68b91 Driver core / Documentation fixes for 5.10-rc2
Here is one tiny debugfs change to fix up an API where the last user was
 successfully fixed up in 5.10-rc1 (so it couldn't be merged earlier),
 and a much larger Documentation/ABI/ update to the files so they can be
 automatically parsed by our tools.
 
 The Documentation/ABI/ updates are just formatting issues, small ones to
 bring the files into parsable format, and have been acked by numerous
 subsystem maintainers and the documentation maintainer.  I figured it
 was good to get this into 5.10-rc2 to help with the merge issues that
 would arise if these were to stick in linux-next until 5.11-rc1.
 
 The debugfs change has been in linux-next for a long time, and the
 Documentation updates only for the last linux-next release.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-5.10-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core and documentation fixes from Greg KH:
 "Here is one tiny debugfs change to fix up an API where the last user
  was successfully fixed up in 5.10-rc1 (so it couldn't be merged
  earlier), and a much larger Documentation/ABI/ update to the files so
  they can be automatically parsed by our tools.

  The Documentation/ABI/ updates are just formatting issues, small ones
  to bring the files into parsable format, and have been acked by
  numerous subsystem maintainers and the documentation maintainer. I
  figured it was good to get this into 5.10-rc2 to help wih the merge
  issues that would arise if these were to stick in linux-next until
  5.11-rc1.

  The debugfs change has been in linux-next for a long time, and the
  Documentation updates only for the last linux-next release"

* tag 'driver-core-5.10-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (40 commits)
  scripts: get_abi.pl: assume ReST format by default
  docs: ABI: sysfs-class-led-trigger-pattern: remove hw_pattern duplication
  docs: ABI: sysfs-class-backlight: unify ABI documentation
  docs: ABI: sysfs-c2port: remove a duplicated entry
  docs: ABI: sysfs-class-power: unify duplicated properties
  docs: ABI: unify /sys/class/leds/<led>/brightness documentation
  docs: ABI: stable: remove a duplicated documentation
  docs: ABI: change read/write attributes
  docs: ABI: cleanup several ABI documents
  docs: ABI: sysfs-bus-nvdimm: use the right format for ABI
  docs: ABI: vdso: use the right format for ABI
  docs: ABI: fix syntax to be parsed using ReST notation
  docs: ABI: convert testing/configfs-acpi to ReST
  docs: Kconfig/Makefile: add a check for broken ABI files
  docs: abi-testing.rst: enable --rst-sources when building docs
  docs: ABI: don't escape ReST-incompatible chars from obsolete and removed
  docs: ABI: create a 2-depth index for ABI
  docs: ABI: make it parse ABI/stable as ReST-compatible files
  docs: ABI: sysfs-uevent: make it compatible with ReST output
  docs: ABI: testing: make the files compatible with ReST output
  ...
2020-11-01 09:59:13 -08:00
Linus Torvalds
53760f9b74 flexible-array member conversion patches for 5.10-rc2
Hi Linus,
 
 Please, pull the following patches that replace zero-length arrays with
 flexible-array members.
 
 Thanks
 --
 Gustavo
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Merge tag 'flexible-array-conversions-5.10-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux

Pull more flexible-array member conversions from Gustavo A. R. Silva:
 "Replace zero-length arrays with flexible-array members"

* tag 'flexible-array-conversions-5.10-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux:
  printk: ringbuffer: Replace zero-length array with flexible-array member
  net/smc: Replace zero-length array with flexible-array member
  net/mlx5: Replace zero-length array with flexible-array member
  mei: hw: Replace zero-length array with flexible-array member
  gve: Replace zero-length array with flexible-array member
  Bluetooth: btintel: Replace zero-length array with flexible-array member
  scsi: target: tcmu: Replace zero-length array with flexible-array member
  ima: Replace zero-length array with flexible-array member
  enetc: Replace zero-length array with flexible-array member
  fs: Replace zero-length array with flexible-array member
  Bluetooth: Replace zero-length array with flexible-array member
  params: Replace zero-length array with flexible-array member
  tracepoint: Replace zero-length array with flexible-array member
  platform/chrome: cros_ec_proto: Replace zero-length array with flexible-array member
  platform/chrome: cros_ec_commands: Replace zero-length array with flexible-array member
  mailbox: zynqmp-ipi-message: Replace zero-length array with flexible-array member
  dmaengine: ti-cppi5: Replace zero-length array with flexible-array member
2020-10-31 14:31:28 -07:00
Linus Torvalds
cf9446cc8e io_uring-5.10-2020-10-30
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Merge tag 'io_uring-5.10-2020-10-30' of git://git.kernel.dk/linux-block

Pull io_uring fixes from Jens Axboe:

 - Fixes for linked timeouts (Pavel)

 - Set IO_WQ_WORK_CONCURRENT early for async offload (Pavel)

 - Two minor simplifications that make the code easier to read and
   follow (Pavel)

* tag 'io_uring-5.10-2020-10-30' of git://git.kernel.dk/linux-block:
  io_uring: use type appropriate io_kiocb handler for double poll
  io_uring: simplify __io_queue_sqe()
  io_uring: simplify nxt propagation in io_queue_sqe
  io_uring: don't miss setting IO_WQ_WORK_CONCURRENT
  io_uring: don't defer put of cancelled ltimeout
  io_uring: always clear LINK_TIMEOUT after cancel
  io_uring: don't adjust LINK_HEAD in cancel ltimeout
  io_uring: remove opcode check on ltimeout kill
2020-10-30 14:55:36 -07:00
Linus Torvalds
f5d808567a for-5.10-rc1-tag
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Merge tag 'for-5.10-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:

 - lockdep fixes:
     - drop path locks before manipulating sysfs objects or qgroups
     - preliminary fixes before tree locks get switched to rwsem
     - use annotated seqlock

 - build warning fixes (printk format)

 - fix relocation vs fallocate race

 - tree checker properly validates number of stripes and parity

 - readahead vs device replace fixes

 - iomap dio fix for unnecessary buffered io fallback

* tag 'for-5.10-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: convert data_seqcount to seqcount_mutex_t
  btrfs: don't fallback to buffered read if we don't need to
  btrfs: add a helper to read the tree_root commit root for backref lookup
  btrfs: drop the path before adding qgroup items when enabling qgroups
  btrfs: fix readahead hang and use-after-free after removing a device
  btrfs: fix use-after-free on readahead extent after failure to create it
  btrfs: tree-checker: validate number of chunk stripes and parity
  btrfs: tree-checker: fix incorrect printk format
  btrfs: drop the path before adding block group sysfs files
  btrfs: fix relocation failure due to race with fallocate
2020-10-30 13:29:49 -07:00
Greg Kroah-Hartman
0d519cbf38 debugfs: remove return value of debugfs_create_devm_seqfile()
No one checks the return value of debugfs_create_devm_seqfile(), as it's
not needed, so make the return value void, so that no one tries to do so
in the future.

Link: https://lore.kernel.org/r/20201023131037.2500765-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-10-30 08:37:39 +01:00
Gustavo A. R. Silva
5e01fdff04 fs: Replace zero-length array with flexible-array member
There is a regular need in the kernel to provide a way to declare having a
dynamically sized set of trailing elements in a structure. Kernel code should
always use “flexible array members”[1] for these cases. The older style of
one-element or zero-length arrays should no longer be used[2].

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://www.kernel.org/doc/html/v5.9-rc1/process/deprecated.html#zero-length-and-one-element-arrays

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2020-10-29 17:22:59 -05:00
Linus Torvalds
598a597636 AFS fixes
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Merge tag 'afs-fixes-20201029' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

Pull AFS fixes from David Howells:

 - Fix copy_file_range() to an afs file now returning EINVAL if the
   splice_write file op isn't supplied.

 - Fix a deref-before-check in afs_unuse_cell().

 - Fix a use-after-free in afs_xattr_get_acl().

 - Fix afs to not try to clear PG_writeback when laundering a page.

 - Fix afs to take a ref on a page that it sets PG_private on and to
   drop that ref when clearing PG_private. This is done through recently
   added helpers.

 - Fix a page leak if write_begin() fails.

 - Fix afs_write_begin() to not alter the dirty region info stored in
   page->private, but rather do this in afs_write_end() instead when we
   know what we actually changed.

 - Fix afs_invalidatepage() to alter the dirty region info on a page
   when partial page invalidation occurs so that we don't inadvertantly
   include a span of zeros that will get written back if a page gets
   laundered due to a remote 3rd-party induced invalidation.

   We mustn't, however, reduce the dirty region if the page has been
   seen to be mapped (ie. we got called through the page_mkwrite vector)
   as the page might still be mapped and we might lose data if the file
   is extended again.

 - Fix the dirty region info to have a lower resolution if the size of
   the page is too large for this to be encoded (e.g. powerpc32 with 64K
   pages).

   Note that this might not be the ideal way to handle this, since it
   may allow some leakage of undirtied zero bytes to the server's copy
   in the case of a 3rd-party conflict.

To aid the last two fixes, two additional changes:

 - Wrap the manipulations of the dirty region info stored in
   page->private into helper functions.

 - Alter the encoding of the dirty region so that the region bounds can
   be stored with one fewer bit, making a bit available for the
   indication of mappedness.

* tag 'afs-fixes-20201029' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  afs: Fix dirty-region encoding on ppc32 with 64K pages
  afs: Fix afs_invalidatepage to adjust the dirty region
  afs: Alter dirty range encoding in page->private
  afs: Wrap page->private manipulations in inline functions
  afs: Fix where page->private is set during write
  afs: Fix page leak on afs_write_begin() failure
  afs: Fix to take ref on page when PG_private is set
  afs: Fix afs_launder_page to not clear PG_writeback
  afs: Fix a use after free in afs_xattr_get_acl()
  afs: Fix tracing deref-before-check
  afs: Fix copy_file_range()
2020-10-29 10:13:09 -07:00
Linus Torvalds
58130a6cd0 Bug fixes for the new ext4 fast commit feature, plus a fix for the
data=journal bug fix.  Also use the generic casefolding support which
 has now landed in fs/libfs.c for 5.10.
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Merge tag 'ext4_for_linus_fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

Pull ext4 fixes from Ted Ts'o:
 "Bug fixes for the new ext4 fast commit feature, plus a fix for the
  'data=journal' bug fix.

  Also use the generic casefolding support which has now landed in
  fs/libfs.c for 5.10"

* tag 'ext4_for_linus_fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  ext4: indicate that fast_commit is available via /sys/fs/ext4/feature/...
  ext4: use generic casefolding support
  ext4: do not use extent after put_bh
  ext4: use IS_ERR() for error checking of path
  ext4: fix mmap write protection for data=journal mode
  jbd2: fix a kernel-doc markup
  ext4: use s_mount_flags instead of s_mount_state for fast commit state
  ext4: make num of fast commit blocks configurable
  ext4: properly check for dirty state in ext4_inode_datasync_dirty()
  ext4: fix double locking in ext4_fc_commit_dentry_updates()
2020-10-29 09:36:11 -07:00
David Howells
2d9900f26a afs: Fix dirty-region encoding on ppc32 with 64K pages
The dirty region bounds stored in page->private on an afs page are 15 bits
on a 32-bit box and can, at most, represent a range of up to 32K within a
32K page with a resolution of 1 byte.  This is a problem for powerpc32 with
64K pages enabled.

Further, transparent huge pages may get up to 2M, which will be a problem
for the afs filesystem on all 32-bit arches in the future.

Fix this by decreasing the resolution.  For the moment, a 64K page will
have a resolution determined from PAGE_SIZE.  In the future, the page will
need to be passed in to the helper functions so that the page size can be
assessed and the resolution determined dynamically.

Note that this might not be the ideal way to handle this, since it may
allow some leakage of undirtied zero bytes to the server's copy in the case
of a 3rd-party conflict.  Fixing that would require a separately allocated
record and is a more complicated fix.

Fixes: 4343d00872 ("afs: Get rid of the afs_writeback record")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
2020-10-29 13:53:04 +00:00
David Howells
f86726a69d afs: Fix afs_invalidatepage to adjust the dirty region
Fix afs_invalidatepage() to adjust the dirty region recorded in
page->private when truncating a page.  If the dirty region is entirely
removed, then the private data is cleared and the page dirty state is
cleared.

Without this, if the page is truncated and then expanded again by truncate,
zeros from the expanded, but no-longer dirty region may get written back to
the server if the page gets laundered due to a conflicting 3rd-party write.

It mustn't, however, shorten the dirty region of the page if that page is
still mmapped and has been marked dirty by afs_page_mkwrite(), so a flag is
stored in page->private to record this.

Fixes: 4343d00872 ("afs: Get rid of the afs_writeback record")
Signed-off-by: David Howells <dhowells@redhat.com>
2020-10-29 13:53:04 +00:00
David Howells
65dd2d6072 afs: Alter dirty range encoding in page->private
Currently, page->private on an afs page is used to store the range of
dirtied data within the page, where the range includes the lower bound, but
excludes the upper bound (e.g. 0-1 is a range covering a single byte).

This, however, requires a superfluous bit for the last-byte bound so that
on a 4KiB page, it can say 0-4096 to indicate the whole page, the idea
being that having both numbers the same would indicate an empty range.
This is unnecessary as the PG_private bit is clear if it's an empty range
(as is PG_dirty).

Alter the way the dirty range is encoded in page->private such that the
upper bound is reduced by 1 (e.g. 0-0 is then specified the same single
byte range mentioned above).

Applying this to both bounds frees up two bits, one of which can be used in
a future commit.

This allows the afs filesystem to be compiled on ppc32 with 64K pages;
without this, the following warnings are seen:

../fs/afs/internal.h: In function 'afs_page_dirty_to':
../fs/afs/internal.h:881:15: warning: right shift count >= width of type [-Wshift-count-overflow]
  881 |  return (priv >> __AFS_PAGE_PRIV_SHIFT) & __AFS_PAGE_PRIV_MASK;
      |               ^~
../fs/afs/internal.h: In function 'afs_page_dirty':
../fs/afs/internal.h:886:28: warning: left shift count >= width of type [-Wshift-count-overflow]
  886 |  return ((unsigned long)to << __AFS_PAGE_PRIV_SHIFT) | from;
      |                            ^~

Fixes: 4343d00872 ("afs: Get rid of the afs_writeback record")
Signed-off-by: David Howells <dhowells@redhat.com>
2020-10-29 13:53:04 +00:00
David Howells
185f0c7073 afs: Wrap page->private manipulations in inline functions
The afs filesystem uses page->private to store the dirty range within a
page such that in the event of a conflicting 3rd-party write to the server,
we write back just the bits that got changed locally.

However, there are a couple of problems with this:

 (1) I need a bit to note if the page might be mapped so that partial
     invalidation doesn't shrink the range.

 (2) There aren't necessarily sufficient bits to store the entire range of
     data altered (say it's a 32-bit system with 64KiB pages or transparent
     huge pages are in use).

So wrap the accesses in inline functions so that future commits can change
how this works.

Also move them out of the tracing header into the in-directory header.
There's not really any need for them to be in the tracing header.

Signed-off-by: David Howells <dhowells@redhat.com>
2020-10-29 13:53:04 +00:00
David Howells
f792e3ac82 afs: Fix where page->private is set during write
In afs, page->private is set to indicate the dirty region of a page.  This
is done in afs_write_begin(), but that can't take account of whether the
copy into the page actually worked.

Fix this by moving the change of page->private into afs_write_end().

Fixes: 4343d00872 ("afs: Get rid of the afs_writeback record")
Signed-off-by: David Howells <dhowells@redhat.com>
2020-10-29 13:53:04 +00:00
David Howells
21db2cdc66 afs: Fix page leak on afs_write_begin() failure
Fix the leak of the target page in afs_write_begin() when it fails.

Fixes: 15b4650e55 ("afs: convert to new aops")
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Nick Piggin <npiggin@gmail.com>
2020-10-29 13:53:04 +00:00
David Howells
fa04a40b16 afs: Fix to take ref on page when PG_private is set
Fix afs to take a ref on a page when it sets PG_private on it and to drop
the ref when removing the flag.

Note that in afs_write_begin(), a lot of the time, PG_private is already
set on a page to which we're going to add some data.  In such a case, we
leave the bit set and mustn't increment the page count.

As suggested by Matthew Wilcox, use attach/detach_page_private() where
possible.

Fixes: 31143d5d51 ("AFS: implement basic file write support")
Reported-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
2020-10-29 13:53:04 +00:00
Theodore Ts'o
6694875ef8 ext4: indicate that fast_commit is available via /sys/fs/ext4/feature/...
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2020-10-28 13:43:22 -04:00
Daniel Rosenberg
f8f4acb6cd ext4: use generic casefolding support
This switches ext4 over to the generic support provided in libfs.

Since casefolded dentries behave the same in ext4 and f2fs, we decrease
the maintenance burden by unifying them, and any optimizations will
immediately apply to both.

Signed-off-by: Daniel Rosenberg <drosen@google.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20201028050820.1636571-1-drosen@google.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2020-10-28 13:43:13 -04:00
yangerkun
d7dce9e085 ext4: do not use extent after put_bh
ext4_ext_search_right() will read more extent blocks and call put_bh
after we get the information we need.  However, ret_ex will break this
and may cause use-after-free once pagecache has been freed.  Fix it by
copying the extent structure if needed.

Signed-off-by: yangerkun <yangerkun@huawei.com>
Link: https://lore.kernel.org/r/20201028055617.2569255-1-yangerkun@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
2020-10-28 13:43:13 -04:00
Harshad Shirwadkar
8c9be1e58a ext4: use IS_ERR() for error checking of path
With this fix, fast commit recovery code uses IS_ERR() for path
returned by ext4_find_extent.

Fixes: 8016e29f43 ("ext4: fast commit recovery path")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201027204342.2794949-1-harshadshirwadkar@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2020-10-28 13:43:07 -04:00
Jan Kara
b5b18160a3 ext4: fix mmap write protection for data=journal mode
Commit afb585a97f "ext4: data=journal: write-protect pages on
j_submit_inode_data_buffers()") added calls ext4_jbd2_inode_add_write()
to track inode ranges whose mappings need to get write-protected during
transaction commits.  However the added calls use wrong start of a range
(0 instead of page offset) and so write protection is not necessarily
effective.  Use correct range start to fix the problem.

Fixes: afb585a97f ("ext4: data=journal: write-protect pages on j_submit_inode_data_buffers()")
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20201027132751.29858-1-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2020-10-28 13:42:42 -04:00
Harshad Shirwadkar
ababea77bc ext4: use s_mount_flags instead of s_mount_state for fast commit state
Ext4's fast commit related transient states should use
sb->s_mount_flags instead of persistent sb->s_mount_state.

Fixes: 8016e29f43 ("ext4: fast commit recovery path")
Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201027044915.2553163-3-harshadshirwadkar@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2020-10-28 13:42:10 -04:00
Harshad Shirwadkar
e029c5f279 ext4: make num of fast commit blocks configurable
This patch reserves a field in the jbd2 superblock for number of fast
commit blocks. When this value is non-zero, Ext4 uses this field to
set the number of fast commit blocks.

Fixes: 6866d7b3f2 ("ext4/jbd2: add fast commit initialization")
Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201027044915.2553163-2-harshadshirwadkar@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2020-10-28 13:42:03 -04:00
Andrea Righi
d0520df724 ext4: properly check for dirty state in ext4_inode_datasync_dirty()
ext4_inode_datasync_dirty() needs to return 'true' if the inode is
dirty, 'false' otherwise, but the logic seems to be incorrectly changed
by commit aa75f4d3da ("ext4: main fast-commit commit path").

This introduces a problem with swap files that are always failing to be
activated, showing this error in dmesg:

 [   34.406479] swapon: file is not committed

Simple test case to reproduce the problem:

  # fallocate -l 8G swapfile
  # chmod 0600 swapfile
  # mkswap swapfile
  # swapon swapfile

Fix the logic to return the proper state of the inode.

Link: https://lore.kernel.org/lkml/20201024131333.GA32124@xps-13-7390
Fixes: 8016e29f43 ("ext4: fast commit recovery path")
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201027044915.2553163-1-harshadshirwadkar@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2020-10-28 13:41:23 -04:00
Harshad Shirwadkar
5112e9a540 ext4: fix double locking in ext4_fc_commit_dentry_updates()
Fixed double locking of sbi->s_fc_lock in the above function
as reported by kernel-test-robot.

Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201023161339.1449437-1-harshadshirwadkar@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2020-10-28 13:41:16 -04:00
David Howells
d383e346f9 afs: Fix afs_launder_page to not clear PG_writeback
Fix afs_launder_page() to not clear PG_writeback on the page it is
laundering as the flag isn't set in this case.

Fixes: 4343d00872 ("afs: Get rid of the afs_writeback record")
Signed-off-by: David Howells <dhowells@redhat.com>
2020-10-27 22:05:56 +00:00
Dan Carpenter
248c944e21 afs: Fix a use after free in afs_xattr_get_acl()
The "op" pointer is freed earlier when we call afs_put_operation().

Fixes: e49c7b2f6d ("afs: Build an abstraction around an "operation" concept")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Colin Ian King <colin.king@canonical.com>
2020-10-27 22:05:56 +00:00
David Howells
acc080d15d afs: Fix tracing deref-before-check
The patch dca54a7bbb: "afs: Add tracing for cell refcount and active user
count" from Oct 13, 2020, leads to the following Smatch complaint:

    fs/afs/cell.c:596 afs_unuse_cell()
    warn: variable dereferenced before check 'cell' (see line 592)

Fix this by moving the retrieval of the cell debug ID to after the check of
the validity of the cell pointer.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: dca54a7bbb ("afs: Add tracing for cell refcount and active user count")
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Dan Carpenter <dan.carpenter@oracle.com>
2020-10-27 22:05:56 +00:00
David Howells
06a17bbe1d afs: Fix copy_file_range()
The prevention of splice-write without explicit ops made the
copy_file_write() syscall to an afs file (as done by the generic/112
xfstest) fail with EINVAL.

Fix by using iter_file_splice_write() for afs.

Fixes: 36e2c7421f ("fs: don't allow splice read/write without explicit ops")
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2020-10-27 22:05:56 +00:00
Davidlohr Bueso
d5c8238849 btrfs: convert data_seqcount to seqcount_mutex_t
By doing so we can associate the sequence counter to the chunk_mutex
for lockdep purposes (compiled-out otherwise), the mutex is otherwise
used on the write side.
Also avoid explicitly disabling preemption around the write region as it
will now be done automatically by the seqcount machinery based on the
lock type.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-27 15:11:51 +01:00
Johannes Thumshirn
0425e7badb btrfs: don't fallback to buffered read if we don't need to
Since we switched to the iomap infrastructure in b5ff9f1a96e8f ("btrfs:
switch to iomap for direct IO") we're calling generic_file_buffered_read()
directly and not via generic_file_read_iter() anymore.

If the read could read everything there is no need to bother calling
generic_file_buffered_read(), like it is handled in
generic_file_read_iter().

If we call generic_file_buffered_read() in this case we can hit a
situation where we do an invalid readahead and cause this UBSAN splat
in fstest generic/091:

  run fstests generic/091 at 2020-10-21 10:52:32
  ================================================================================
  UBSAN: shift-out-of-bounds in ./include/linux/log2.h:57:13
  shift exponent 64 is too large for 64-bit type 'long unsigned int'
  CPU: 0 PID: 656 Comm: fsx Not tainted 5.9.0-rc7+ #821
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4-rebuilt.opensuse.org 04/01/2014
  Call Trace:
   __dump_stack lib/dump_stack.c:77
   dump_stack+0x57/0x70 lib/dump_stack.c:118
   ubsan_epilogue+0x5/0x40 lib/ubsan.c:148
   __ubsan_handle_shift_out_of_bounds.cold+0x61/0xe9 lib/ubsan.c:395
   __roundup_pow_of_two ./include/linux/log2.h:57
   get_init_ra_size mm/readahead.c:318
   ondemand_readahead.cold+0x16/0x2c mm/readahead.c:530
   generic_file_buffered_read+0x3ac/0x840 mm/filemap.c:2199
   call_read_iter ./include/linux/fs.h:1876
   new_sync_read+0x102/0x180 fs/read_write.c:415
   vfs_read+0x11c/0x1a0 fs/read_write.c:481
   ksys_read+0x4f/0xc0 fs/read_write.c:615
   do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
   entry_SYSCALL_64_after_hwframe+0x44/0xa9 arch/x86/entry/entry_64.S:118
  RIP: 0033:0x7fe87fee992e
  RSP: 002b:00007ffe01605278 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
  RAX: ffffffffffffffda RBX: 000000000004f000 RCX: 00007fe87fee992e
  RDX: 0000000000004000 RSI: 0000000001677000 RDI: 0000000000000003
  RBP: 000000000004f000 R08: 0000000000004000 R09: 000000000004f000
  R10: 0000000000053000 R11: 0000000000000246 R12: 0000000000004000
  R13: 0000000000000000 R14: 000000000007a120 R15: 0000000000000000
  ================================================================================
  BTRFS info (device nullb0): has skinny extents
  BTRFS info (device nullb0): ZONED mode enabled, zone size 268435456 B
  BTRFS info (device nullb0): enabling ssd optimizations

Fixes: f85781fb50 ("btrfs: switch to iomap for direct IO")
Reviewed-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-27 15:11:37 +01:00
Matthew Wilcox (Oracle)
9480b4e75b cachefiles: Handle readpage error correctly
If ->readpage returns an error, it has already unlocked the page.

Fixes: 5e929b33c3 ("CacheFiles: Handle truncate unlocking the page we're reading")
Cc: stable@vger.kernel.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-26 10:42:54 -07:00
Josef Bacik
49d11bead7 btrfs: add a helper to read the tree_root commit root for backref lookup
I got the following lockdep splat with tree locks converted to rwsem
patches on btrfs/104:

  ======================================================
  WARNING: possible circular locking dependency detected
  5.9.0+ #102 Not tainted
  ------------------------------------------------------
  btrfs-cleaner/903 is trying to acquire lock:
  ffff8e7fab6ffe30 (btrfs-root-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x32/0x170

  but task is already holding lock:
  ffff8e7fab628a88 (&fs_info->commit_root_sem){++++}-{3:3}, at: btrfs_find_all_roots+0x41/0x80

  which lock already depends on the new lock.

  the existing dependency chain (in reverse order) is:

  -> #3 (&fs_info->commit_root_sem){++++}-{3:3}:
	 down_read+0x40/0x130
	 caching_thread+0x53/0x5a0
	 btrfs_work_helper+0xfa/0x520
	 process_one_work+0x238/0x540
	 worker_thread+0x55/0x3c0
	 kthread+0x13a/0x150
	 ret_from_fork+0x1f/0x30

  -> #2 (&caching_ctl->mutex){+.+.}-{3:3}:
	 __mutex_lock+0x7e/0x7b0
	 btrfs_cache_block_group+0x1e0/0x510
	 find_free_extent+0xb6e/0x12f0
	 btrfs_reserve_extent+0xb3/0x1b0
	 btrfs_alloc_tree_block+0xb1/0x330
	 alloc_tree_block_no_bg_flush+0x4f/0x60
	 __btrfs_cow_block+0x11d/0x580
	 btrfs_cow_block+0x10c/0x220
	 commit_cowonly_roots+0x47/0x2e0
	 btrfs_commit_transaction+0x595/0xbd0
	 sync_filesystem+0x74/0x90
	 generic_shutdown_super+0x22/0x100
	 kill_anon_super+0x14/0x30
	 btrfs_kill_super+0x12/0x20
	 deactivate_locked_super+0x36/0xa0
	 cleanup_mnt+0x12d/0x190
	 task_work_run+0x5c/0xa0
	 exit_to_user_mode_prepare+0x1df/0x200
	 syscall_exit_to_user_mode+0x54/0x280
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #1 (&space_info->groups_sem){++++}-{3:3}:
	 down_read+0x40/0x130
	 find_free_extent+0x2ed/0x12f0
	 btrfs_reserve_extent+0xb3/0x1b0
	 btrfs_alloc_tree_block+0xb1/0x330
	 alloc_tree_block_no_bg_flush+0x4f/0x60
	 __btrfs_cow_block+0x11d/0x580
	 btrfs_cow_block+0x10c/0x220
	 commit_cowonly_roots+0x47/0x2e0
	 btrfs_commit_transaction+0x595/0xbd0
	 sync_filesystem+0x74/0x90
	 generic_shutdown_super+0x22/0x100
	 kill_anon_super+0x14/0x30
	 btrfs_kill_super+0x12/0x20
	 deactivate_locked_super+0x36/0xa0
	 cleanup_mnt+0x12d/0x190
	 task_work_run+0x5c/0xa0
	 exit_to_user_mode_prepare+0x1df/0x200
	 syscall_exit_to_user_mode+0x54/0x280
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #0 (btrfs-root-00){++++}-{3:3}:
	 __lock_acquire+0x1167/0x2150
	 lock_acquire+0xb9/0x3d0
	 down_read_nested+0x43/0x130
	 __btrfs_tree_read_lock+0x32/0x170
	 __btrfs_read_lock_root_node+0x3a/0x50
	 btrfs_search_slot+0x614/0x9d0
	 btrfs_find_root+0x35/0x1b0
	 btrfs_read_tree_root+0x61/0x120
	 btrfs_get_root_ref+0x14b/0x600
	 find_parent_nodes+0x3e6/0x1b30
	 btrfs_find_all_roots_safe+0xb4/0x130
	 btrfs_find_all_roots+0x60/0x80
	 btrfs_qgroup_trace_extent_post+0x27/0x40
	 btrfs_add_delayed_data_ref+0x3fd/0x460
	 btrfs_free_extent+0x42/0x100
	 __btrfs_mod_ref+0x1d7/0x2f0
	 walk_up_proc+0x11c/0x400
	 walk_up_tree+0xf0/0x180
	 btrfs_drop_snapshot+0x1c7/0x780
	 btrfs_clean_one_deleted_snapshot+0xfb/0x110
	 cleaner_kthread+0xd4/0x140
	 kthread+0x13a/0x150
	 ret_from_fork+0x1f/0x30

  other info that might help us debug this:

  Chain exists of:
    btrfs-root-00 --> &caching_ctl->mutex --> &fs_info->commit_root_sem

   Possible unsafe locking scenario:

	 CPU0                    CPU1
	 ----                    ----
    lock(&fs_info->commit_root_sem);
				 lock(&caching_ctl->mutex);
				 lock(&fs_info->commit_root_sem);
    lock(btrfs-root-00);

   *** DEADLOCK ***

  3 locks held by btrfs-cleaner/903:
   #0: ffff8e7fab628838 (&fs_info->cleaner_mutex){+.+.}-{3:3}, at: cleaner_kthread+0x6e/0x140
   #1: ffff8e7faadac640 (sb_internal){.+.+}-{0:0}, at: start_transaction+0x40b/0x5c0
   #2: ffff8e7fab628a88 (&fs_info->commit_root_sem){++++}-{3:3}, at: btrfs_find_all_roots+0x41/0x80

  stack backtrace:
  CPU: 0 PID: 903 Comm: btrfs-cleaner Not tainted 5.9.0+ #102
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-2.fc32 04/01/2014
  Call Trace:
   dump_stack+0x8b/0xb0
   check_noncircular+0xcf/0xf0
   __lock_acquire+0x1167/0x2150
   ? __bfs+0x42/0x210
   lock_acquire+0xb9/0x3d0
   ? __btrfs_tree_read_lock+0x32/0x170
   down_read_nested+0x43/0x130
   ? __btrfs_tree_read_lock+0x32/0x170
   __btrfs_tree_read_lock+0x32/0x170
   __btrfs_read_lock_root_node+0x3a/0x50
   btrfs_search_slot+0x614/0x9d0
   ? find_held_lock+0x2b/0x80
   btrfs_find_root+0x35/0x1b0
   ? do_raw_spin_unlock+0x4b/0xa0
   btrfs_read_tree_root+0x61/0x120
   btrfs_get_root_ref+0x14b/0x600
   find_parent_nodes+0x3e6/0x1b30
   btrfs_find_all_roots_safe+0xb4/0x130
   btrfs_find_all_roots+0x60/0x80
   btrfs_qgroup_trace_extent_post+0x27/0x40
   btrfs_add_delayed_data_ref+0x3fd/0x460
   btrfs_free_extent+0x42/0x100
   __btrfs_mod_ref+0x1d7/0x2f0
   walk_up_proc+0x11c/0x400
   walk_up_tree+0xf0/0x180
   btrfs_drop_snapshot+0x1c7/0x780
   ? btrfs_clean_one_deleted_snapshot+0x73/0x110
   btrfs_clean_one_deleted_snapshot+0xfb/0x110
   cleaner_kthread+0xd4/0x140
   ? btrfs_alloc_root+0x50/0x50
   kthread+0x13a/0x150
   ? kthread_create_worker_on_cpu+0x40/0x40
   ret_from_fork+0x1f/0x30
  BTRFS info (device sdb): disk space caching is enabled
  BTRFS info (device sdb): has skinny extents

This happens because qgroups does a backref lookup when we create a
delayed ref.  From here it may have to look up a root from an indirect
ref, which does a normal lookup on the tree_root, which takes the read
lock on the tree_root nodes.

To fix this we need to add a variant for looking up roots that searches
the commit root of the tree_root.  Then when we do the backref search
using the commit root we are sure to not take any locks on the tree_root
nodes.  This gets rid of the lockdep splat when running btrfs/104.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-26 15:04:57 +01:00
Josef Bacik
5223cc60b4 btrfs: drop the path before adding qgroup items when enabling qgroups
When enabling qgroups we walk the tree_root and then add a qgroup item
for every root that we have.  This creates a lock dependency on the
tree_root and qgroup_root, which results in the following lockdep splat
(with tree locks using rwsem), eg. in tests btrfs/017 or btrfs/022:

  ======================================================
  WARNING: possible circular locking dependency detected
  5.9.0-default+ #1299 Not tainted
  ------------------------------------------------------
  btrfs/24552 is trying to acquire lock:
  ffff9142dfc5f630 (btrfs-quota-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x35/0x1c0 [btrfs]

  but task is already holding lock:
  ffff9142dfc5d0b0 (btrfs-root-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x35/0x1c0 [btrfs]

  which lock already depends on the new lock.

  the existing dependency chain (in reverse order) is:

  -> #1 (btrfs-root-00){++++}-{3:3}:
	 __lock_acquire+0x3fb/0x730
	 lock_acquire.part.0+0x6a/0x130
	 down_read_nested+0x46/0x130
	 __btrfs_tree_read_lock+0x35/0x1c0 [btrfs]
	 __btrfs_read_lock_root_node+0x3a/0x50 [btrfs]
	 btrfs_search_slot_get_root+0x11d/0x290 [btrfs]
	 btrfs_search_slot+0xc3/0x9f0 [btrfs]
	 btrfs_insert_item+0x6e/0x140 [btrfs]
	 btrfs_create_tree+0x1cb/0x240 [btrfs]
	 btrfs_quota_enable+0xcd/0x790 [btrfs]
	 btrfs_ioctl_quota_ctl+0xc9/0xe0 [btrfs]
	 __x64_sys_ioctl+0x83/0xa0
	 do_syscall_64+0x2d/0x70
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #0 (btrfs-quota-00){++++}-{3:3}:
	 check_prev_add+0x91/0xc30
	 validate_chain+0x491/0x750
	 __lock_acquire+0x3fb/0x730
	 lock_acquire.part.0+0x6a/0x130
	 down_read_nested+0x46/0x130
	 __btrfs_tree_read_lock+0x35/0x1c0 [btrfs]
	 __btrfs_read_lock_root_node+0x3a/0x50 [btrfs]
	 btrfs_search_slot_get_root+0x11d/0x290 [btrfs]
	 btrfs_search_slot+0xc3/0x9f0 [btrfs]
	 btrfs_insert_empty_items+0x58/0xa0 [btrfs]
	 add_qgroup_item.part.0+0x72/0x210 [btrfs]
	 btrfs_quota_enable+0x3bb/0x790 [btrfs]
	 btrfs_ioctl_quota_ctl+0xc9/0xe0 [btrfs]
	 __x64_sys_ioctl+0x83/0xa0
	 do_syscall_64+0x2d/0x70
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  other info that might help us debug this:

   Possible unsafe locking scenario:

	 CPU0                    CPU1
	 ----                    ----
    lock(btrfs-root-00);
				 lock(btrfs-quota-00);
				 lock(btrfs-root-00);
    lock(btrfs-quota-00);

   *** DEADLOCK ***

  5 locks held by btrfs/24552:
   #0: ffff9142df431478 (sb_writers#10){.+.+}-{0:0}, at: mnt_want_write_file+0x22/0xa0
   #1: ffff9142f9b10cc0 (&fs_info->subvol_sem){++++}-{3:3}, at: btrfs_ioctl_quota_ctl+0x7b/0xe0 [btrfs]
   #2: ffff9142f9b11a08 (&fs_info->qgroup_ioctl_lock){+.+.}-{3:3}, at: btrfs_quota_enable+0x3b/0x790 [btrfs]
   #3: ffff9142df431698 (sb_internal#2){.+.+}-{0:0}, at: start_transaction+0x406/0x510 [btrfs]
   #4: ffff9142dfc5d0b0 (btrfs-root-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x35/0x1c0 [btrfs]

  stack backtrace:
  CPU: 1 PID: 24552 Comm: btrfs Not tainted 5.9.0-default+ #1299
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba527-rebuilt.opensuse.org 04/01/2014
  Call Trace:
   dump_stack+0x77/0x97
   check_noncircular+0xf3/0x110
   check_prev_add+0x91/0xc30
   validate_chain+0x491/0x750
   __lock_acquire+0x3fb/0x730
   lock_acquire.part.0+0x6a/0x130
   ? __btrfs_tree_read_lock+0x35/0x1c0 [btrfs]
   ? lock_acquire+0xc4/0x140
   ? __btrfs_tree_read_lock+0x35/0x1c0 [btrfs]
   down_read_nested+0x46/0x130
   ? __btrfs_tree_read_lock+0x35/0x1c0 [btrfs]
   __btrfs_tree_read_lock+0x35/0x1c0 [btrfs]
   ? btrfs_root_node+0xd9/0x200 [btrfs]
   __btrfs_read_lock_root_node+0x3a/0x50 [btrfs]
   btrfs_search_slot_get_root+0x11d/0x290 [btrfs]
   btrfs_search_slot+0xc3/0x9f0 [btrfs]
   btrfs_insert_empty_items+0x58/0xa0 [btrfs]
   add_qgroup_item.part.0+0x72/0x210 [btrfs]
   btrfs_quota_enable+0x3bb/0x790 [btrfs]
   btrfs_ioctl_quota_ctl+0xc9/0xe0 [btrfs]
   __x64_sys_ioctl+0x83/0xa0
   do_syscall_64+0x2d/0x70
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fix this by dropping the path whenever we find a root item, add the
qgroup item, and then re-lookup the root item we found and continue
processing roots.

Reported-by: David Sterba <dsterba@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-26 15:04:57 +01:00
Filipe Manana
66d204a16c btrfs: fix readahead hang and use-after-free after removing a device
Very sporadically I had test case btrfs/069 from fstests hanging (for
years, it is not a recent regression), with the following traces in
dmesg/syslog:

  [162301.160628] BTRFS info (device sdc): dev_replace from /dev/sdd (devid 2) to /dev/sdg started
  [162301.181196] BTRFS info (device sdc): scrub: finished on devid 4 with status: 0
  [162301.287162] BTRFS info (device sdc): dev_replace from /dev/sdd (devid 2) to /dev/sdg finished
  [162513.513792] INFO: task btrfs-transacti:1356167 blocked for more than 120 seconds.
  [162513.514318]       Not tainted 5.9.0-rc6-btrfs-next-69 #1
  [162513.514522] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
  [162513.514747] task:btrfs-transacti state:D stack:    0 pid:1356167 ppid:     2 flags:0x00004000
  [162513.514751] Call Trace:
  [162513.514761]  __schedule+0x5ce/0xd00
  [162513.514765]  ? _raw_spin_unlock_irqrestore+0x3c/0x60
  [162513.514771]  schedule+0x46/0xf0
  [162513.514844]  wait_current_trans+0xde/0x140 [btrfs]
  [162513.514850]  ? finish_wait+0x90/0x90
  [162513.514864]  start_transaction+0x37c/0x5f0 [btrfs]
  [162513.514879]  transaction_kthread+0xa4/0x170 [btrfs]
  [162513.514891]  ? btrfs_cleanup_transaction+0x660/0x660 [btrfs]
  [162513.514894]  kthread+0x153/0x170
  [162513.514897]  ? kthread_stop+0x2c0/0x2c0
  [162513.514902]  ret_from_fork+0x22/0x30
  [162513.514916] INFO: task fsstress:1356184 blocked for more than 120 seconds.
  [162513.515192]       Not tainted 5.9.0-rc6-btrfs-next-69 #1
  [162513.515431] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
  [162513.515680] task:fsstress        state:D stack:    0 pid:1356184 ppid:1356177 flags:0x00004000
  [162513.515682] Call Trace:
  [162513.515688]  __schedule+0x5ce/0xd00
  [162513.515691]  ? _raw_spin_unlock_irqrestore+0x3c/0x60
  [162513.515697]  schedule+0x46/0xf0
  [162513.515712]  wait_current_trans+0xde/0x140 [btrfs]
  [162513.515716]  ? finish_wait+0x90/0x90
  [162513.515729]  start_transaction+0x37c/0x5f0 [btrfs]
  [162513.515743]  btrfs_attach_transaction_barrier+0x1f/0x50 [btrfs]
  [162513.515753]  btrfs_sync_fs+0x61/0x1c0 [btrfs]
  [162513.515758]  ? __ia32_sys_fdatasync+0x20/0x20
  [162513.515761]  iterate_supers+0x87/0xf0
  [162513.515765]  ksys_sync+0x60/0xb0
  [162513.515768]  __do_sys_sync+0xa/0x10
  [162513.515771]  do_syscall_64+0x33/0x80
  [162513.515774]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
  [162513.515781] RIP: 0033:0x7f5238f50bd7
  [162513.515782] Code: Bad RIP value.
  [162513.515784] RSP: 002b:00007fff67b978e8 EFLAGS: 00000206 ORIG_RAX: 00000000000000a2
  [162513.515786] RAX: ffffffffffffffda RBX: 000055b1fad2c560 RCX: 00007f5238f50bd7
  [162513.515788] RDX: 00000000ffffffff RSI: 000000000daf0e74 RDI: 000000000000003a
  [162513.515789] RBP: 0000000000000032 R08: 000000000000000a R09: 00007f5239019be0
  [162513.515791] R10: fffffffffffff24f R11: 0000000000000206 R12: 000000000000003a
  [162513.515792] R13: 00007fff67b97950 R14: 00007fff67b97906 R15: 000055b1fad1a340
  [162513.515804] INFO: task fsstress:1356185 blocked for more than 120 seconds.
  [162513.516064]       Not tainted 5.9.0-rc6-btrfs-next-69 #1
  [162513.516329] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
  [162513.516617] task:fsstress        state:D stack:    0 pid:1356185 ppid:1356177 flags:0x00000000
  [162513.516620] Call Trace:
  [162513.516625]  __schedule+0x5ce/0xd00
  [162513.516628]  ? _raw_spin_unlock_irqrestore+0x3c/0x60
  [162513.516634]  schedule+0x46/0xf0
  [162513.516647]  wait_current_trans+0xde/0x140 [btrfs]
  [162513.516650]  ? finish_wait+0x90/0x90
  [162513.516662]  start_transaction+0x4d7/0x5f0 [btrfs]
  [162513.516679]  btrfs_setxattr_trans+0x3c/0x100 [btrfs]
  [162513.516686]  __vfs_setxattr+0x66/0x80
  [162513.516691]  __vfs_setxattr_noperm+0x70/0x200
  [162513.516697]  vfs_setxattr+0x6b/0x120
  [162513.516703]  setxattr+0x125/0x240
  [162513.516709]  ? lock_acquire+0xb1/0x480
  [162513.516712]  ? mnt_want_write+0x20/0x50
  [162513.516721]  ? rcu_read_lock_any_held+0x8e/0xb0
  [162513.516723]  ? preempt_count_add+0x49/0xa0
  [162513.516725]  ? __sb_start_write+0x19b/0x290
  [162513.516727]  ? preempt_count_add+0x49/0xa0
  [162513.516732]  path_setxattr+0xba/0xd0
  [162513.516739]  __x64_sys_setxattr+0x27/0x30
  [162513.516741]  do_syscall_64+0x33/0x80
  [162513.516743]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
  [162513.516745] RIP: 0033:0x7f5238f56d5a
  [162513.516746] Code: Bad RIP value.
  [162513.516748] RSP: 002b:00007fff67b97868 EFLAGS: 00000202 ORIG_RAX: 00000000000000bc
  [162513.516750] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f5238f56d5a
  [162513.516751] RDX: 000055b1fbb0d5a0 RSI: 00007fff67b978a0 RDI: 000055b1fbb0d470
  [162513.516753] RBP: 000055b1fbb0d5a0 R08: 0000000000000001 R09: 00007fff67b97700
  [162513.516754] R10: 0000000000000004 R11: 0000000000000202 R12: 0000000000000004
  [162513.516756] R13: 0000000000000024 R14: 0000000000000001 R15: 00007fff67b978a0
  [162513.516767] INFO: task fsstress:1356196 blocked for more than 120 seconds.
  [162513.517064]       Not tainted 5.9.0-rc6-btrfs-next-69 #1
  [162513.517365] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
  [162513.517763] task:fsstress        state:D stack:    0 pid:1356196 ppid:1356177 flags:0x00004000
  [162513.517780] Call Trace:
  [162513.517786]  __schedule+0x5ce/0xd00
  [162513.517789]  ? _raw_spin_unlock_irqrestore+0x3c/0x60
  [162513.517796]  schedule+0x46/0xf0
  [162513.517810]  wait_current_trans+0xde/0x140 [btrfs]
  [162513.517814]  ? finish_wait+0x90/0x90
  [162513.517829]  start_transaction+0x37c/0x5f0 [btrfs]
  [162513.517845]  btrfs_attach_transaction_barrier+0x1f/0x50 [btrfs]
  [162513.517857]  btrfs_sync_fs+0x61/0x1c0 [btrfs]
  [162513.517862]  ? __ia32_sys_fdatasync+0x20/0x20
  [162513.517865]  iterate_supers+0x87/0xf0
  [162513.517869]  ksys_sync+0x60/0xb0
  [162513.517872]  __do_sys_sync+0xa/0x10
  [162513.517875]  do_syscall_64+0x33/0x80
  [162513.517878]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
  [162513.517881] RIP: 0033:0x7f5238f50bd7
  [162513.517883] Code: Bad RIP value.
  [162513.517885] RSP: 002b:00007fff67b978e8 EFLAGS: 00000206 ORIG_RAX: 00000000000000a2
  [162513.517887] RAX: ffffffffffffffda RBX: 000055b1fad2c560 RCX: 00007f5238f50bd7
  [162513.517889] RDX: 0000000000000000 RSI: 000000007660add2 RDI: 0000000000000053
  [162513.517891] RBP: 0000000000000032 R08: 0000000000000067 R09: 00007f5239019be0
  [162513.517893] R10: fffffffffffff24f R11: 0000000000000206 R12: 0000000000000053
  [162513.517895] R13: 00007fff67b97950 R14: 00007fff67b97906 R15: 000055b1fad1a340
  [162513.517908] INFO: task fsstress:1356197 blocked for more than 120 seconds.
  [162513.518298]       Not tainted 5.9.0-rc6-btrfs-next-69 #1
  [162513.518672] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
  [162513.519157] task:fsstress        state:D stack:    0 pid:1356197 ppid:1356177 flags:0x00000000
  [162513.519160] Call Trace:
  [162513.519165]  __schedule+0x5ce/0xd00
  [162513.519168]  ? _raw_spin_unlock_irqrestore+0x3c/0x60
  [162513.519174]  schedule+0x46/0xf0
  [162513.519190]  wait_current_trans+0xde/0x140 [btrfs]
  [162513.519193]  ? finish_wait+0x90/0x90
  [162513.519206]  start_transaction+0x4d7/0x5f0 [btrfs]
  [162513.519222]  btrfs_create+0x57/0x200 [btrfs]
  [162513.519230]  lookup_open+0x522/0x650
  [162513.519246]  path_openat+0x2b8/0xa50
  [162513.519270]  do_filp_open+0x91/0x100
  [162513.519275]  ? find_held_lock+0x32/0x90
  [162513.519280]  ? lock_acquired+0x33b/0x470
  [162513.519285]  ? do_raw_spin_unlock+0x4b/0xc0
  [162513.519287]  ? _raw_spin_unlock+0x29/0x40
  [162513.519295]  do_sys_openat2+0x20d/0x2d0
  [162513.519300]  do_sys_open+0x44/0x80
  [162513.519304]  do_syscall_64+0x33/0x80
  [162513.519307]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
  [162513.519309] RIP: 0033:0x7f5238f4a903
  [162513.519310] Code: Bad RIP value.
  [162513.519312] RSP: 002b:00007fff67b97758 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
  [162513.519314] RAX: ffffffffffffffda RBX: 00000000ffffffff RCX: 00007f5238f4a903
  [162513.519316] RDX: 0000000000000000 RSI: 00000000000001b6 RDI: 000055b1fbb0d470
  [162513.519317] RBP: 00007fff67b978c0 R08: 0000000000000001 R09: 0000000000000002
  [162513.519319] R10: 00007fff67b974f7 R11: 0000000000000246 R12: 0000000000000013
  [162513.519320] R13: 00000000000001b6 R14: 00007fff67b97906 R15: 000055b1fad1c620
  [162513.519332] INFO: task btrfs:1356211 blocked for more than 120 seconds.
  [162513.519727]       Not tainted 5.9.0-rc6-btrfs-next-69 #1
  [162513.520115] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
  [162513.520508] task:btrfs           state:D stack:    0 pid:1356211 ppid:1356178 flags:0x00004002
  [162513.520511] Call Trace:
  [162513.520516]  __schedule+0x5ce/0xd00
  [162513.520519]  ? _raw_spin_unlock_irqrestore+0x3c/0x60
  [162513.520525]  schedule+0x46/0xf0
  [162513.520544]  btrfs_scrub_pause+0x11f/0x180 [btrfs]
  [162513.520548]  ? finish_wait+0x90/0x90
  [162513.520562]  btrfs_commit_transaction+0x45a/0xc30 [btrfs]
  [162513.520574]  ? start_transaction+0xe0/0x5f0 [btrfs]
  [162513.520596]  btrfs_dev_replace_finishing+0x6d8/0x711 [btrfs]
  [162513.520619]  btrfs_dev_replace_by_ioctl.cold+0x1cc/0x1fd [btrfs]
  [162513.520639]  btrfs_ioctl+0x2a25/0x36f0 [btrfs]
  [162513.520643]  ? do_sigaction+0xf3/0x240
  [162513.520645]  ? find_held_lock+0x32/0x90
  [162513.520648]  ? do_sigaction+0xf3/0x240
  [162513.520651]  ? lock_acquired+0x33b/0x470
  [162513.520655]  ? _raw_spin_unlock_irq+0x24/0x50
  [162513.520657]  ? lockdep_hardirqs_on+0x7d/0x100
  [162513.520660]  ? _raw_spin_unlock_irq+0x35/0x50
  [162513.520662]  ? do_sigaction+0xf3/0x240
  [162513.520671]  ? __x64_sys_ioctl+0x83/0xb0
  [162513.520672]  __x64_sys_ioctl+0x83/0xb0
  [162513.520677]  do_syscall_64+0x33/0x80
  [162513.520679]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
  [162513.520681] RIP: 0033:0x7fc3cd307d87
  [162513.520682] Code: Bad RIP value.
  [162513.520684] RSP: 002b:00007ffe30a56bb8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010
  [162513.520686] RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007fc3cd307d87
  [162513.520687] RDX: 00007ffe30a57a30 RSI: 00000000ca289435 RDI: 0000000000000003
  [162513.520689] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
  [162513.520690] R10: 0000000000000008 R11: 0000000000000202 R12: 0000000000000003
  [162513.520692] R13: 0000557323a212e0 R14: 00007ffe30a5a520 R15: 0000000000000001
  [162513.520703]
		  Showing all locks held in the system:
  [162513.520712] 1 lock held by khungtaskd/54:
  [162513.520713]  #0: ffffffffb40a91a0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x15/0x197
  [162513.520728] 1 lock held by in:imklog/596:
  [162513.520729]  #0: ffff8f3f0d781400 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x4d/0x60
  [162513.520782] 1 lock held by btrfs-transacti/1356167:
  [162513.520784]  #0: ffff8f3d810cc848 (&fs_info->transaction_kthread_mutex){+.+.}-{3:3}, at: transaction_kthread+0x4a/0x170 [btrfs]
  [162513.520798] 1 lock held by btrfs/1356190:
  [162513.520800]  #0: ffff8f3d57644470 (sb_writers#15){.+.+}-{0:0}, at: mnt_want_write_file+0x22/0x60
  [162513.520805] 1 lock held by fsstress/1356184:
  [162513.520806]  #0: ffff8f3d576440e8 (&type->s_umount_key#62){++++}-{3:3}, at: iterate_supers+0x6f/0xf0
  [162513.520811] 3 locks held by fsstress/1356185:
  [162513.520812]  #0: ffff8f3d57644470 (sb_writers#15){.+.+}-{0:0}, at: mnt_want_write+0x20/0x50
  [162513.520815]  #1: ffff8f3d80a650b8 (&type->i_mutex_dir_key#10){++++}-{3:3}, at: vfs_setxattr+0x50/0x120
  [162513.520820]  #2: ffff8f3d57644690 (sb_internal#2){.+.+}-{0:0}, at: start_transaction+0x40e/0x5f0 [btrfs]
  [162513.520833] 1 lock held by fsstress/1356196:
  [162513.520834]  #0: ffff8f3d576440e8 (&type->s_umount_key#62){++++}-{3:3}, at: iterate_supers+0x6f/0xf0
  [162513.520838] 3 locks held by fsstress/1356197:
  [162513.520839]  #0: ffff8f3d57644470 (sb_writers#15){.+.+}-{0:0}, at: mnt_want_write+0x20/0x50
  [162513.520843]  #1: ffff8f3d506465e8 (&type->i_mutex_dir_key#10){++++}-{3:3}, at: path_openat+0x2a7/0xa50
  [162513.520846]  #2: ffff8f3d57644690 (sb_internal#2){.+.+}-{0:0}, at: start_transaction+0x40e/0x5f0 [btrfs]
  [162513.520858] 2 locks held by btrfs/1356211:
  [162513.520859]  #0: ffff8f3d810cde30 (&fs_info->dev_replace.lock_finishing_cancel_unmount){+.+.}-{3:3}, at: btrfs_dev_replace_finishing+0x52/0x711 [btrfs]
  [162513.520877]  #1: ffff8f3d57644690 (sb_internal#2){.+.+}-{0:0}, at: start_transaction+0x40e/0x5f0 [btrfs]

This was weird because the stack traces show that a transaction commit,
triggered by a device replace operation, is blocking trying to pause any
running scrubs but there are no stack traces of blocked tasks doing a
scrub.

After poking around with drgn, I noticed there was a scrub task that was
constantly running and blocking for shorts periods of time:

  >>> t = find_task(prog, 1356190)
  >>> prog.stack_trace(t)
  #0  __schedule+0x5ce/0xcfc
  #1  schedule+0x46/0xe4
  #2  schedule_timeout+0x1df/0x475
  #3  btrfs_reada_wait+0xda/0x132
  #4  scrub_stripe+0x2a8/0x112f
  #5  scrub_chunk+0xcd/0x134
  #6  scrub_enumerate_chunks+0x29e/0x5ee
  #7  btrfs_scrub_dev+0x2d5/0x91b
  #8  btrfs_ioctl+0x7f5/0x36e7
  #9  __x64_sys_ioctl+0x83/0xb0
  #10 do_syscall_64+0x33/0x77
  #11 entry_SYSCALL_64+0x7c/0x156

Which corresponds to:

int btrfs_reada_wait(void *handle)
{
    struct reada_control *rc = handle;
    struct btrfs_fs_info *fs_info = rc->fs_info;

    while (atomic_read(&rc->elems)) {
        if (!atomic_read(&fs_info->reada_works_cnt))
            reada_start_machine(fs_info);
        wait_event_timeout(rc->wait, atomic_read(&rc->elems) == 0,
                          (HZ + 9) / 10);
    }
(...)

So the counter "rc->elems" was set to 1 and never decreased to 0, causing
the scrub task to loop forever in that function. Then I used the following
script for drgn to check the readahead requests:

  $ cat dump_reada.py
  import sys
  import drgn
  from drgn import NULL, Object, cast, container_of, execscript, \
      reinterpret, sizeof
  from drgn.helpers.linux import *

  mnt_path = b"/home/fdmanana/btrfs-tests/scratch_1"

  mnt = None
  for mnt in for_each_mount(prog, dst = mnt_path):
      pass

  if mnt is None:
      sys.stderr.write(f'Error: mount point {mnt_path} not found\n')
      sys.exit(1)

  fs_info = cast('struct btrfs_fs_info *', mnt.mnt.mnt_sb.s_fs_info)

  def dump_re(re):
      nzones = re.nzones.value_()
      print(f're at {hex(re.value_())}')
      print(f'\t logical {re.logical.value_()}')
      print(f'\t refcnt {re.refcnt.value_()}')
      print(f'\t nzones {nzones}')
      for i in range(nzones):
          dev = re.zones[i].device
          name = dev.name.str.string_()
          print(f'\t\t dev id {dev.devid.value_()} name {name}')
      print()

  for _, e in radix_tree_for_each(fs_info.reada_tree):
      re = cast('struct reada_extent *', e)
      dump_re(re)

  $ drgn dump_reada.py
  re at 0xffff8f3da9d25ad8
          logical 38928384
          refcnt 1
          nzones 1
                 dev id 0 name b'/dev/sdd'
  $

So there was one readahead extent with a single zone corresponding to the
source device of that last device replace operation logged in dmesg/syslog.
Also the ID of that zone's device was 0 which is a special value set in
the source device of a device replace operation when the operation finishes
(constant BTRFS_DEV_REPLACE_DEVID set at btrfs_dev_replace_finishing()),
confirming again that device /dev/sdd was the source of a device replace
operation.

Normally there should be as many zones in the readahead extent as there are
devices, and I wasn't expecting the extent to be in a block group with a
'single' profile, so I went and confirmed with the following drgn script
that there weren't any single profile block groups:

  $ cat dump_block_groups.py
  import sys
  import drgn
  from drgn import NULL, Object, cast, container_of, execscript, \
      reinterpret, sizeof
  from drgn.helpers.linux import *

  mnt_path = b"/home/fdmanana/btrfs-tests/scratch_1"

  mnt = None
  for mnt in for_each_mount(prog, dst = mnt_path):
      pass

  if mnt is None:
      sys.stderr.write(f'Error: mount point {mnt_path} not found\n')
      sys.exit(1)

  fs_info = cast('struct btrfs_fs_info *', mnt.mnt.mnt_sb.s_fs_info)

  BTRFS_BLOCK_GROUP_DATA = (1 << 0)
  BTRFS_BLOCK_GROUP_SYSTEM = (1 << 1)
  BTRFS_BLOCK_GROUP_METADATA = (1 << 2)
  BTRFS_BLOCK_GROUP_RAID0 = (1 << 3)
  BTRFS_BLOCK_GROUP_RAID1 = (1 << 4)
  BTRFS_BLOCK_GROUP_DUP = (1 << 5)
  BTRFS_BLOCK_GROUP_RAID10 = (1 << 6)
  BTRFS_BLOCK_GROUP_RAID5 = (1 << 7)
  BTRFS_BLOCK_GROUP_RAID6 = (1 << 8)
  BTRFS_BLOCK_GROUP_RAID1C3 = (1 << 9)
  BTRFS_BLOCK_GROUP_RAID1C4 = (1 << 10)

  def bg_flags_string(bg):
      flags = bg.flags.value_()
      ret = ''
      if flags & BTRFS_BLOCK_GROUP_DATA:
          ret = 'data'
      if flags & BTRFS_BLOCK_GROUP_METADATA:
          if len(ret) > 0:
              ret += '|'
          ret += 'meta'
      if flags & BTRFS_BLOCK_GROUP_SYSTEM:
          if len(ret) > 0:
              ret += '|'
          ret += 'system'
      if flags & BTRFS_BLOCK_GROUP_RAID0:
          ret += ' raid0'
      elif flags & BTRFS_BLOCK_GROUP_RAID1:
          ret += ' raid1'
      elif flags & BTRFS_BLOCK_GROUP_DUP:
          ret += ' dup'
      elif flags & BTRFS_BLOCK_GROUP_RAID10:
          ret += ' raid10'
      elif flags & BTRFS_BLOCK_GROUP_RAID5:
          ret += ' raid5'
      elif flags & BTRFS_BLOCK_GROUP_RAID6:
          ret += ' raid6'
      elif flags & BTRFS_BLOCK_GROUP_RAID1C3:
          ret += ' raid1c3'
      elif flags & BTRFS_BLOCK_GROUP_RAID1C4:
          ret += ' raid1c4'
      else:
          ret += ' single'

      return ret

  def dump_bg(bg):
      print()
      print(f'block group at {hex(bg.value_())}')
      print(f'\t start {bg.start.value_()} length {bg.length.value_()}')
      print(f'\t flags {bg.flags.value_()} - {bg_flags_string(bg)}')

  bg_root = fs_info.block_group_cache_tree.address_of_()
  for bg in rbtree_inorder_for_each_entry('struct btrfs_block_group', bg_root, 'cache_node'):
      dump_bg(bg)

  $ drgn dump_block_groups.py

  block group at 0xffff8f3d673b0400
         start 22020096 length 16777216
         flags 258 - system raid6

  block group at 0xffff8f3d53ddb400
         start 38797312 length 536870912
         flags 260 - meta raid6

  block group at 0xffff8f3d5f4d9c00
         start 575668224 length 2147483648
         flags 257 - data raid6

  block group at 0xffff8f3d08189000
         start 2723151872 length 67108864
         flags 258 - system raid6

  block group at 0xffff8f3db70ff000
         start 2790260736 length 1073741824
         flags 260 - meta raid6

  block group at 0xffff8f3d5f4dd800
         start 3864002560 length 67108864
         flags 258 - system raid6

  block group at 0xffff8f3d67037000
         start 3931111424 length 2147483648
         flags 257 - data raid6
  $

So there were only 2 reasons left for having a readahead extent with a
single zone: reada_find_zone(), called when creating a readahead extent,
returned NULL either because we failed to find the corresponding block
group or because a memory allocation failed. With some additional and
custom tracing I figured out that on every further ocurrence of the
problem the block group had just been deleted when we were looping to
create the zones for the readahead extent (at reada_find_extent()), so we
ended up with only one zone in the readahead extent, corresponding to a
device that ends up getting replaced.

So after figuring that out it became obvious why the hang happens:

1) Task A starts a scrub on any device of the filesystem, except for
   device /dev/sdd;

2) Task B starts a device replace with /dev/sdd as the source device;

3) Task A calls btrfs_reada_add() from scrub_stripe() and it is currently
   starting to scrub a stripe from block group X. This call to
   btrfs_reada_add() is the one for the extent tree. When btrfs_reada_add()
   calls reada_add_block(), it passes the logical address of the extent
   tree's root node as its 'logical' argument - a value of 38928384;

4) Task A then enters reada_find_extent(), called from reada_add_block().
   It finds there isn't any existing readahead extent for the logical
   address 38928384, so it proceeds to the path of creating a new one.

   It calls btrfs_map_block() to find out which stripes exist for the block
   group X. On the first iteration of the for loop that iterates over the
   stripes, it finds the stripe for device /dev/sdd, so it creates one
   zone for that device and adds it to the readahead extent. Before getting
   into the second iteration of the loop, the cleanup kthread deletes block
   group X because it was empty. So in the iterations for the remaining
   stripes it does not add more zones to the readahead extent, because the
   calls to reada_find_zone() returned NULL because they couldn't find
   block group X anymore.

   As a result the new readahead extent has a single zone, corresponding to
   the device /dev/sdd;

4) Before task A returns to btrfs_reada_add() and queues the readahead job
   for the readahead work queue, task B finishes the device replace and at
   btrfs_dev_replace_finishing() swaps the device /dev/sdd with the new
   device /dev/sdg;

5) Task A returns to reada_add_block(), which increments the counter
   "->elems" of the reada_control structure allocated at btrfs_reada_add().

   Then it returns back to btrfs_reada_add() and calls
   reada_start_machine(). This queues a job in the readahead work queue to
   run the function reada_start_machine_worker(), which calls
   __reada_start_machine().

   At __reada_start_machine() we take the device list mutex and for each
   device found in the current device list, we call
   reada_start_machine_dev() to start the readahead work. However at this
   point the device /dev/sdd was already freed and is not in the device
   list anymore.

   This means the corresponding readahead for the extent at 38928384 is
   never started, and therefore the "->elems" counter of the reada_control
   structure allocated at btrfs_reada_add() never goes down to 0, causing
   the call to btrfs_reada_wait(), done by the scrub task, to wait forever.

Note that the readahead request can be made either after the device replace
started or before it started, however in pratice it is very unlikely that a
device replace is able to start after a readahead request is made and is
able to complete before the readahead request completes - maybe only on a
very small and nearly empty filesystem.

This hang however is not the only problem we can have with readahead and
device removals. When the readahead extent has other zones other than the
one corresponding to the device that is being removed (either by a device
replace or a device remove operation), we risk having a use-after-free on
the device when dropping the last reference of the readahead extent.

For example if we create a readahead extent with two zones, one for the
device /dev/sdd and one for the device /dev/sde:

1) Before the readahead worker starts, the device /dev/sdd is removed,
   and the corresponding btrfs_device structure is freed. However the
   readahead extent still has the zone pointing to the device structure;

2) When the readahead worker starts, it only finds device /dev/sde in the
   current device list of the filesystem;

3) It starts the readahead work, at reada_start_machine_dev(), using the
   device /dev/sde;

4) Then when it finishes reading the extent from device /dev/sde, it calls
   __readahead_hook() which ends up dropping the last reference on the
   readahead extent through the last call to reada_extent_put();

5) At reada_extent_put() it iterates over each zone of the readahead extent
   and attempts to delete an element from the device's 'reada_extents'
   radix tree, resulting in a use-after-free, as the device pointer of the
   zone for /dev/sdd is now stale. We can also access the device after
   dropping the last reference of a zone, through reada_zone_release(),
   also called by reada_extent_put().

And a device remove suffers the same problem, however since it shrinks the
device size down to zero before removing the device, it is very unlikely to
still have readahead requests not completed by the time we free the device,
the only possibility is if the device has a very little space allocated.

While the hang problem is exclusive to scrub, since it is currently the
only user of btrfs_reada_add() and btrfs_reada_wait(), the use-after-free
problem affects any path that triggers readhead, which includes
btree_readahead_hook() and __readahead_hook() (a readahead worker can
trigger readahed for the children of a node) for example - any path that
ends up calling reada_add_block() can trigger the use-after-free after a
device is removed.

So fix this by waiting for any readahead requests for a device to complete
before removing a device, ensuring that while waiting for existing ones no
new ones can be made.

This problem has been around for a very long time - the readahead code was
added in 2011, device remove exists since 2008 and device replace was
introduced in 2013, hard to pick a specific commit for a git Fixes tag.

CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-26 15:03:59 +01:00
Filipe Manana
83bc1560e0 btrfs: fix use-after-free on readahead extent after failure to create it
If we fail to find suitable zones for a new readahead extent, we end up
leaving a stale pointer in the global readahead extents radix tree
(fs_info->reada_tree), which can trigger the following trace later on:

  [13367.696354] BUG: kernel NULL pointer dereference, address: 00000000000000b0
  [13367.696802] #PF: supervisor read access in kernel mode
  [13367.697249] #PF: error_code(0x0000) - not-present page
  [13367.697721] PGD 0 P4D 0
  [13367.698171] Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC PTI
  [13367.698632] CPU: 6 PID: 851214 Comm: btrfs Tainted: G        W         5.9.0-rc6-btrfs-next-69 #1
  [13367.699100] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
  [13367.700069] RIP: 0010:__lock_acquire+0x20a/0x3970
  [13367.700562] Code: ff 1f 0f b7 c0 48 0f (...)
  [13367.701609] RSP: 0018:ffffb14448f57790 EFLAGS: 00010046
  [13367.702140] RAX: 0000000000000000 RBX: 29b935140c15e8cf RCX: 0000000000000000
  [13367.702698] RDX: 0000000000000002 RSI: ffffffffb3d66bd0 RDI: 0000000000000046
  [13367.703240] RBP: ffff8a52ba8ac040 R08: 00000c2866ad9288 R09: 0000000000000001
  [13367.703783] R10: 0000000000000001 R11: 00000000b66d9b53 R12: ffff8a52ba8ac9b0
  [13367.704330] R13: 0000000000000000 R14: ffff8a532b6333e8 R15: 0000000000000000
  [13367.704880] FS:  00007fe1df6b5700(0000) GS:ffff8a5376600000(0000) knlGS:0000000000000000
  [13367.705438] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [13367.705995] CR2: 00000000000000b0 CR3: 000000022cca8004 CR4: 00000000003706e0
  [13367.706565] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  [13367.707127] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  [13367.707686] Call Trace:
  [13367.708246]  ? ___slab_alloc+0x395/0x740
  [13367.708820]  ? reada_add_block+0xae/0xee0 [btrfs]
  [13367.709383]  lock_acquire+0xb1/0x480
  [13367.709955]  ? reada_add_block+0xe0/0xee0 [btrfs]
  [13367.710537]  ? reada_add_block+0xae/0xee0 [btrfs]
  [13367.711097]  ? rcu_read_lock_sched_held+0x5d/0x90
  [13367.711659]  ? kmem_cache_alloc_trace+0x8d2/0x990
  [13367.712221]  ? lock_acquired+0x33b/0x470
  [13367.712784]  _raw_spin_lock+0x34/0x80
  [13367.713356]  ? reada_add_block+0xe0/0xee0 [btrfs]
  [13367.713966]  reada_add_block+0xe0/0xee0 [btrfs]
  [13367.714529]  ? btrfs_root_node+0x15/0x1f0 [btrfs]
  [13367.715077]  btrfs_reada_add+0x117/0x170 [btrfs]
  [13367.715620]  scrub_stripe+0x21e/0x10d0 [btrfs]
  [13367.716141]  ? kvm_sched_clock_read+0x5/0x10
  [13367.716657]  ? __lock_acquire+0x41e/0x3970
  [13367.717184]  ? scrub_chunk+0x60/0x140 [btrfs]
  [13367.717697]  ? find_held_lock+0x32/0x90
  [13367.718254]  ? scrub_chunk+0x60/0x140 [btrfs]
  [13367.718773]  ? lock_acquired+0x33b/0x470
  [13367.719278]  ? scrub_chunk+0xcd/0x140 [btrfs]
  [13367.719786]  scrub_chunk+0xcd/0x140 [btrfs]
  [13367.720291]  scrub_enumerate_chunks+0x270/0x5c0 [btrfs]
  [13367.720787]  ? finish_wait+0x90/0x90
  [13367.721281]  btrfs_scrub_dev+0x1ee/0x620 [btrfs]
  [13367.721762]  ? rcu_read_lock_any_held+0x8e/0xb0
  [13367.722235]  ? preempt_count_add+0x49/0xa0
  [13367.722710]  ? __sb_start_write+0x19b/0x290
  [13367.723192]  btrfs_ioctl+0x7f5/0x36f0 [btrfs]
  [13367.723660]  ? __fget_files+0x101/0x1d0
  [13367.724118]  ? find_held_lock+0x32/0x90
  [13367.724559]  ? __fget_files+0x101/0x1d0
  [13367.724982]  ? __x64_sys_ioctl+0x83/0xb0
  [13367.725399]  __x64_sys_ioctl+0x83/0xb0
  [13367.725802]  do_syscall_64+0x33/0x80
  [13367.726188]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
  [13367.726574] RIP: 0033:0x7fe1df7add87
  [13367.726948] Code: 00 00 00 48 8b 05 09 91 (...)
  [13367.727763] RSP: 002b:00007fe1df6b4d48 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
  [13367.728179] RAX: ffffffffffffffda RBX: 000055ce1fb596a0 RCX: 00007fe1df7add87
  [13367.728604] RDX: 000055ce1fb596a0 RSI: 00000000c400941b RDI: 0000000000000003
  [13367.729021] RBP: 0000000000000000 R08: 00007fe1df6b5700 R09: 0000000000000000
  [13367.729431] R10: 00007fe1df6b5700 R11: 0000000000000246 R12: 00007ffd922b07de
  [13367.729842] R13: 00007ffd922b07df R14: 00007fe1df6b4e40 R15: 0000000000802000
  [13367.730275] Modules linked in: btrfs blake2b_generic xor (...)
  [13367.732638] CR2: 00000000000000b0
  [13367.733166] ---[ end trace d298b6805556acd9 ]---

What happens is the following:

1) At reada_find_extent() we don't find any existing readahead extent for
   the metadata extent starting at logical address X;

2) So we proceed to create a new one. We then call btrfs_map_block() to get
   information about which stripes contain extent X;

3) After that we iterate over the stripes and create only one zone for the
   readahead extent - only one because reada_find_zone() returned NULL for
   all iterations except for one, either because a memory allocation failed
   or it couldn't find the block group of the extent (it may have just been
   deleted);

4) We then add the new readahead extent to the readahead extents radix
   tree at fs_info->reada_tree;

5) Then we iterate over each zone of the new readahead extent, and find
   that the device used for that zone no longer exists, because it was
   removed or it was the source device of a device replace operation.
   Since this left 'have_zone' set to 0, after finishing the loop we jump
   to the 'error' label, call kfree() on the new readahead extent and
   return without removing it from the radix tree at fs_info->reada_tree;

6) Any future call to reada_find_extent() for the logical address X will
   find the stale pointer in the readahead extents radix tree, increment
   its reference counter, which can trigger the use-after-free right
   away or return it to the caller reada_add_block() that results in the
   use-after-free of the example trace above.

So fix this by making sure we delete the readahead extent from the radix
tree if we fail to setup zones for it (when 'have_zone = 0').

Fixes: 3194502118 ("btrfs: reada: bypass adding extent when all zone failed")
CC: stable@vger.kernel.org # 4.9+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-26 15:03:59 +01:00
Daniel Xu
85d07fbe09 btrfs: tree-checker: validate number of chunk stripes and parity
If there's no parity and num_stripes < ncopies, a crafted image can
trigger a division by zero in calc_stripe_length().

The image was generated through fuzzing.

CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=209587
Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-26 15:03:48 +01:00
Pujin Shi
cad69d1396 btrfs: tree-checker: fix incorrect printk format
This patch addresses a compile warning:

fs/btrfs/extent-tree.c: In function '__btrfs_free_extent':
fs/btrfs/extent-tree.c:3187:4: warning: format '%lu' expects argument of type 'long unsigned int', but argument 8 has type 'unsigned int' [-Wformat=]

Fixes: 1c2a07f598 ("btrfs: extent-tree: kill BUG_ON() in __btrfs_free_extent()")
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Pujin Shi <shipujin.t@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-26 15:02:30 +01:00
Josef Bacik
7837fa8870 btrfs: drop the path before adding block group sysfs files
Dave reported a problem with my rwsem conversion patch where we got the
following lockdep splat:

  ======================================================
  WARNING: possible circular locking dependency detected
  5.9.0-default+ #1297 Not tainted
  ------------------------------------------------------
  kswapd0/76 is trying to acquire lock:
  ffff9d5d25df2530 (&delayed_node->mutex){+.+.}-{3:3}, at: __btrfs_release_delayed_node.part.0+0x3f/0x320 [btrfs]

  but task is already holding lock:
  ffffffffa40cbba0 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x5/0x30

  which lock already depends on the new lock.

  the existing dependency chain (in reverse order) is:

  -> #4 (fs_reclaim){+.+.}-{0:0}:
	 __lock_acquire+0x582/0xac0
	 lock_acquire+0xca/0x430
	 fs_reclaim_acquire.part.0+0x25/0x30
	 kmem_cache_alloc+0x30/0x9c0
	 alloc_inode+0x81/0x90
	 iget_locked+0xcd/0x1a0
	 kernfs_get_inode+0x1b/0x130
	 kernfs_get_tree+0x136/0x210
	 sysfs_get_tree+0x1a/0x50
	 vfs_get_tree+0x1d/0xb0
	 path_mount+0x70f/0xa80
	 do_mount+0x75/0x90
	 __x64_sys_mount+0x8e/0xd0
	 do_syscall_64+0x2d/0x70
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #3 (kernfs_mutex){+.+.}-{3:3}:
	 __lock_acquire+0x582/0xac0
	 lock_acquire+0xca/0x430
	 __mutex_lock+0xa0/0xaf0
	 kernfs_add_one+0x23/0x150
	 kernfs_create_dir_ns+0x58/0x80
	 sysfs_create_dir_ns+0x70/0xd0
	 kobject_add_internal+0xbb/0x2d0
	 kobject_add+0x7a/0xd0
	 btrfs_sysfs_add_block_group_type+0x141/0x1d0 [btrfs]
	 btrfs_read_block_groups+0x1f1/0x8c0 [btrfs]
	 open_ctree+0x981/0x1108 [btrfs]
	 btrfs_mount_root.cold+0xe/0xb0 [btrfs]
	 legacy_get_tree+0x2d/0x60
	 vfs_get_tree+0x1d/0xb0
	 fc_mount+0xe/0x40
	 vfs_kern_mount.part.0+0x71/0x90
	 btrfs_mount+0x13b/0x3e0 [btrfs]
	 legacy_get_tree+0x2d/0x60
	 vfs_get_tree+0x1d/0xb0
	 path_mount+0x70f/0xa80
	 do_mount+0x75/0x90
	 __x64_sys_mount+0x8e/0xd0
	 do_syscall_64+0x2d/0x70
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #2 (btrfs-extent-00){++++}-{3:3}:
	 __lock_acquire+0x582/0xac0
	 lock_acquire+0xca/0x430
	 down_read_nested+0x45/0x220
	 __btrfs_tree_read_lock+0x35/0x1c0 [btrfs]
	 __btrfs_read_lock_root_node+0x3a/0x50 [btrfs]
	 btrfs_search_slot+0x6d4/0xfd0 [btrfs]
	 check_committed_ref+0x69/0x200 [btrfs]
	 btrfs_cross_ref_exist+0x65/0xb0 [btrfs]
	 run_delalloc_nocow+0x446/0x9b0 [btrfs]
	 btrfs_run_delalloc_range+0x61/0x6a0 [btrfs]
	 writepage_delalloc+0xae/0x160 [btrfs]
	 __extent_writepage+0x262/0x420 [btrfs]
	 extent_write_cache_pages+0x2b6/0x510 [btrfs]
	 extent_writepages+0x43/0x90 [btrfs]
	 do_writepages+0x40/0xe0
	 __writeback_single_inode+0x62/0x610
	 writeback_sb_inodes+0x20f/0x500
	 wb_writeback+0xef/0x4a0
	 wb_do_writeback+0x49/0x2e0
	 wb_workfn+0x81/0x340
	 process_one_work+0x233/0x5d0
	 worker_thread+0x50/0x3b0
	 kthread+0x137/0x150
	 ret_from_fork+0x1f/0x30

  -> #1 (btrfs-fs-00){++++}-{3:3}:
	 __lock_acquire+0x582/0xac0
	 lock_acquire+0xca/0x430
	 down_read_nested+0x45/0x220
	 __btrfs_tree_read_lock+0x35/0x1c0 [btrfs]
	 __btrfs_read_lock_root_node+0x3a/0x50 [btrfs]
	 btrfs_search_slot+0x6d4/0xfd0 [btrfs]
	 btrfs_lookup_inode+0x3a/0xc0 [btrfs]
	 __btrfs_update_delayed_inode+0x93/0x2c0 [btrfs]
	 __btrfs_commit_inode_delayed_items+0x7de/0x850 [btrfs]
	 __btrfs_run_delayed_items+0x8e/0x140 [btrfs]
	 btrfs_commit_transaction+0x367/0xbc0 [btrfs]
	 btrfs_mksubvol+0x2db/0x470 [btrfs]
	 btrfs_mksnapshot+0x7b/0xb0 [btrfs]
	 __btrfs_ioctl_snap_create+0x16f/0x1a0 [btrfs]
	 btrfs_ioctl_snap_create_v2+0xb0/0xf0 [btrfs]
	 btrfs_ioctl+0xd0b/0x2690 [btrfs]
	 __x64_sys_ioctl+0x6f/0xa0
	 do_syscall_64+0x2d/0x70
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #0 (&delayed_node->mutex){+.+.}-{3:3}:
	 check_prev_add+0x91/0xc60
	 validate_chain+0xa6e/0x2a20
	 __lock_acquire+0x582/0xac0
	 lock_acquire+0xca/0x430
	 __mutex_lock+0xa0/0xaf0
	 __btrfs_release_delayed_node.part.0+0x3f/0x320 [btrfs]
	 btrfs_evict_inode+0x3cc/0x560 [btrfs]
	 evict+0xd6/0x1c0
	 dispose_list+0x48/0x70
	 prune_icache_sb+0x54/0x80
	 super_cache_scan+0x121/0x1a0
	 do_shrink_slab+0x16d/0x3b0
	 shrink_slab+0xb1/0x2e0
	 shrink_node+0x230/0x6a0
	 balance_pgdat+0x325/0x750
	 kswapd+0x206/0x4d0
	 kthread+0x137/0x150
	 ret_from_fork+0x1f/0x30

  other info that might help us debug this:

  Chain exists of:
    &delayed_node->mutex --> kernfs_mutex --> fs_reclaim

   Possible unsafe locking scenario:

	 CPU0                    CPU1
	 ----                    ----
    lock(fs_reclaim);
				 lock(kernfs_mutex);
				 lock(fs_reclaim);
    lock(&delayed_node->mutex);

   *** DEADLOCK ***

  3 locks held by kswapd0/76:
   #0: ffffffffa40cbba0 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x5/0x30
   #1: ffffffffa40b8b58 (shrinker_rwsem){++++}-{3:3}, at: shrink_slab+0x54/0x2e0
   #2: ffff9d5d322390e8 (&type->s_umount_key#26){++++}-{3:3}, at: trylock_super+0x16/0x50

  stack backtrace:
  CPU: 2 PID: 76 Comm: kswapd0 Not tainted 5.9.0-default+ #1297
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba527-rebuilt.opensuse.org 04/01/2014
  Call Trace:
   dump_stack+0x77/0x97
   check_noncircular+0xff/0x110
   ? save_trace+0x50/0x470
   check_prev_add+0x91/0xc60
   validate_chain+0xa6e/0x2a20
   ? save_trace+0x50/0x470
   __lock_acquire+0x582/0xac0
   lock_acquire+0xca/0x430
   ? __btrfs_release_delayed_node.part.0+0x3f/0x320 [btrfs]
   __mutex_lock+0xa0/0xaf0
   ? __btrfs_release_delayed_node.part.0+0x3f/0x320 [btrfs]
   ? __lock_acquire+0x582/0xac0
   ? __btrfs_release_delayed_node.part.0+0x3f/0x320 [btrfs]
   ? btrfs_evict_inode+0x30b/0x560 [btrfs]
   ? __btrfs_release_delayed_node.part.0+0x3f/0x320 [btrfs]
   __btrfs_release_delayed_node.part.0+0x3f/0x320 [btrfs]
   btrfs_evict_inode+0x3cc/0x560 [btrfs]
   evict+0xd6/0x1c0
   dispose_list+0x48/0x70
   prune_icache_sb+0x54/0x80
   super_cache_scan+0x121/0x1a0
   do_shrink_slab+0x16d/0x3b0
   shrink_slab+0xb1/0x2e0
   shrink_node+0x230/0x6a0
   balance_pgdat+0x325/0x750
   kswapd+0x206/0x4d0
   ? finish_wait+0x90/0x90
   ? balance_pgdat+0x750/0x750
   kthread+0x137/0x150
   ? kthread_mod_delayed_work+0xc0/0xc0
   ret_from_fork+0x1f/0x30

This happens because we are still holding the path open when we start
adding the sysfs files for the block groups, which creates a dependency
on fs_reclaim via the tree lock.  Fix this by dropping the path before
we start doing anything with sysfs.

Reported-by: David Sterba <dsterba@suse.com>
CC: stable@vger.kernel.org # 5.8+
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-26 15:01:34 +01:00
Joe Perches
33def8498f treewide: Convert macro and uses of __section(foo) to __section("foo")
Use a more generic form for __section that requires quotes to avoid
complications with clang and gcc differences.

Remove the quote operator # from compiler_attributes.h __section macro.

Convert all unquoted __section(foo) uses to quoted __section("foo").
Also convert __attribute__((section("foo"))) uses to __section("foo")
even if the __attribute__ has multiple list entry forms.

Conversion done using the script at:

    https://lore.kernel.org/lkml/75393e5ddc272dc7403de74d645e6c6e0f4e70eb.camel@perches.com/2-convert_section.pl

Signed-off-by: Joe Perches <joe@perches.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@gooogle.com>
Reviewed-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-25 14:51:49 -07:00
Jens Axboe
c8b5e2600a io_uring: use type appropriate io_kiocb handler for double poll
io_poll_double_wake() is called for both request types - both pure poll
requests, and internal polls. This means that we should be using the
right handler based on the request type. Use the one that the original
caller already assigned for the waitqueue handling, that will always
match the correct type.

Cc: stable@vger.kernel.org # v5.8+
Reported-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-25 13:53:26 -06:00
Linus Torvalds
c10037f832 add support for stat of various special file types (WSL reparse points for char, block, fifo)
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Merge tag '5.10-rc-smb3-fixes-part2' of git://git.samba.org/sfrench/cifs-2.6

Pull more cifs updates from Steve French:
 "Add support for stat of various special file types (WSL reparse points
  for char, block, fifo)"

* tag '5.10-rc-smb3-fixes-part2' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: update internal module version number
  smb3: add some missing definitions from MS-FSCC
  smb3: remove two unused variables
  smb3: add support for stat of WSL reparse points for special file types
2020-10-25 11:05:04 -07:00
Linus Torvalds
af0041875c io_uring-5.10-2020-10-24
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Merge tag 'io_uring-5.10-2020-10-24' of git://git.kernel.dk/linux-block

Pull io_uring fixes from Jens Axboe:

 - fsize was missed in previous unification of work flags

 - Few fixes cleaning up the flags unification creds cases (Pavel)

 - Fix NUMA affinities for completely unplugged/replugged node for io-wq

 - Two fallout fixes from the set_fs changes. One local to io_uring, one
   for the splice entry point that io_uring uses.

 - Linked timeout fixes (Pavel)

 - Removal of ->flush() ->files work-around that we don't need anymore
   with referenced files (Pavel)

 - Various cleanups (Pavel)

* tag 'io_uring-5.10-2020-10-24' of git://git.kernel.dk/linux-block:
  splice: change exported internal do_splice() helper to take kernel offset
  io_uring: make loop_rw_iter() use original user supplied pointers
  io_uring: remove req cancel in ->flush()
  io-wq: re-set NUMA node affinities if CPUs come online
  io_uring: don't reuse linked_timeout
  io_uring: unify fsize with def->work_flags
  io_uring: fix racy REQ_F_LINK_TIMEOUT clearing
  io_uring: do poll's hash_node init in common code
  io_uring: inline io_poll_task_handler()
  io_uring: remove extra ->file check in poll prep
  io_uring: make cached_cq_overflow non atomic_t
  io_uring: inline io_fail_links()
  io_uring: kill ref get/drop in personality init
  io_uring: flags-based creds init in queue
2020-10-24 12:40:18 -07:00
Linus Torvalds
0eac1102e9 Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull misc vfs updates from Al Viro:
 "Assorted stuff all over the place (the largest group here is
  Christoph's stat cleanups)"

* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fs: remove KSTAT_QUERY_FLAGS
  fs: remove vfs_stat_set_lookup_flags
  fs: move vfs_fstatat out of line
  fs: implement vfs_stat and vfs_lstat in terms of vfs_fstatat
  fs: remove vfs_statx_fd
  fs: omfs: use kmemdup() rather than kmalloc+memcpy
  [PATCH] reduce boilerplate in fsid handling
  fs: Remove duplicated flag O_NDELAY occurring twice in VALID_OPEN_FLAGS
  selftests: mount: add nosymfollow tests
  Add a "nosymfollow" mount option.
2020-10-24 12:26:05 -07:00
Steve French
aef0388aa9 cifs: update internal module version number
To 2.29

Signed-off-by: Steve French <stfrench@microsoft.com>
2020-10-23 23:41:49 -05:00
Linus Torvalds
f11901ed72 Fixes for 5.10-rc1:
- Make fallocate check the alignment of its arguments against the
 fundamental allocation unit of the volume the file lives on, so that we
 don't trigger the fs' alignment checks.
 - Cancel unprocessed log intents immediately when log recovery fails, to
 avoid a log deadlock.
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Merge tag 'xfs-5.10-merge-7' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull xfs fixes from Darrick Wong:
 "Two bug fixes that trickled in during the merge window:

   - Make fallocate check the alignment of its arguments against the
     fundamental allocation unit of the volume the file lives on, so
     that we don't trigger the fs' alignment checks.

   - Cancel unprocessed log intents immediately when log recovery fails,
     to avoid a log deadlock"

* tag 'xfs-5.10-merge-7' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  xfs: cancel intents immediately if process_intents fails
  xfs: fix fallocate functions when rtextsize is larger than 1
2020-10-23 17:15:06 -07:00
Steve French
7d03ae4dc4 smb3: add some missing definitions from MS-FSCC
Add some structures and defines that were recently added to
the protocol documentation (see MS-FSCC sections 2.3.29-2.3.34).

Signed-off-by: Steve French <stfrench@microsoft.com>
2020-10-23 15:38:10 -05:00
Steve French
6a87266c04 smb3: remove two unused variables
Fix two unused variables in commit
"add support for stat of WSL reparse points for special file types"

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-10-23 15:38:10 -05:00
Steve French
2e4564b31b smb3: add support for stat of WSL reparse points for special file types
This is needed so when mounting to Windows we do not
misinterpret various special files created by Linux (WSL) as symlinks.
An earlier patch addressed readdir.  This patch fixes stat (getattr).

With this patch:
  File: /mnt1/char
  Size: 0          Blocks: 0          IO Block: 16384  character special file
Device: 34h/52d Inode: 844424930132069  Links: 1     Device type: 0,0
Access: (0755/crwxr-xr-x)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2020-10-21 17:46:51.839458900 -0500
Modify: 2020-10-21 17:46:51.839458900 -0500
Change: 2020-10-21 18:30:39.797358800 -0500
 Birth: -
  File: /mnt1/fifo
  Size: 0          Blocks: 0          IO Block: 16384  fifo
Device: 34h/52d Inode: 1125899906842722  Links: 1
Access: (0755/prwxr-xr-x)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2020-10-21 16:21:37.259249700 -0500
Modify: 2020-10-21 16:21:37.259249700 -0500
Change: 2020-10-21 18:30:39.797358800 -0500
 Birth: -
  File: /mnt1/block
  Size: 0          Blocks: 0          IO Block: 16384  block special file
Device: 34h/52d Inode: 844424930132068  Links: 1     Device type: 0,0
Access: (0755/brwxr-xr-x)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2020-10-21 17:10:47.913103200 -0500
Modify: 2020-10-21 17:10:47.913103200 -0500
Change: 2020-10-21 18:30:39.796725500 -0500
 Birth: -

without the patch all show up incorrectly as symlinks with annoying "operation not supported error also returned"
  File: /mnt1/charstat: cannot read symbolic link '/mnt1/char': Operation not supported

  Size: 0          Blocks: 0          IO Block: 16384  symbolic link
Device: 34h/52d Inode: 844424930132069  Links: 1
Access: (0000/l---------)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2020-10-21 17:46:51.839458900 -0500
Modify: 2020-10-21 17:46:51.839458900 -0500
Change: 2020-10-21 18:30:39.797358800 -0500
 Birth: -
  File: /mnt1/fifostat: cannot read symbolic link '/mnt1/fifo': Operation not supported

  Size: 0          Blocks: 0          IO Block: 16384  symbolic link
Device: 34h/52d Inode: 1125899906842722  Links: 1
Access: (0000/l---------)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2020-10-21 16:21:37.259249700 -0500
Modify: 2020-10-21 16:21:37.259249700 -0500
Change: 2020-10-21 18:30:39.797358800 -0500
 Birth: -
  File: /mnt1/blockstat: cannot read symbolic link '/mnt1/block': Operation not supported

  Size: 0          Blocks: 0          IO Block: 16384  symbolic link
Device: 34h/52d Inode: 844424930132068  Links: 1
Access: (0000/l---------)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2020-10-21 17:10:47.913103200 -0500
Modify: 2020-10-21 17:10:47.913103200 -0500
Change: 2020-10-21 18:30:39.796725500 -0500

Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
2020-10-23 15:38:10 -05:00
Pavel Begunkov
0d63c148d6 io_uring: simplify __io_queue_sqe()
Restructure __io_queue_sqe() so it follows simple if/else if/else
control flow. It's more readable and removes extra goto/labels.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-23 13:07:12 -06:00
Pavel Begunkov
9aaf354352 io_uring: simplify nxt propagation in io_queue_sqe
Don't overuse goto's, complex control flow doesn't make compilers happy
and makes code harder to read.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-23 13:07:12 -06:00