Use unlocked page lookup for inmem() to avoid object lock contention

Reviewed By: kib, markj
Submitted by: mlaier
Sponsored by: Dell EMC
Differential Revision: https://reviews.freebsd.org/D26653

Revert r366340.

CR wasn't finished and it breaks the build.

Use unlocked page lookup for inmem() to avoid object lock contention

Reviewed By: kib, markj
Sponsored by: Dell EMC Isilon
Submitted by: mlaier
Differential Revision: https://reviews.freebsd.org/D26

Use unlocked page lookup for inmem() to avoid object lock contention

Reviewed By: kib, markj
Sponsored by: Dell EMC Isilon
Submitted by: mlaier
Differential Revision: https://reviews.freebsd.org/D26597

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kern: clean up empty lines in .c and .h files

MFH

Sponsored by: Rubicon Communications, LLC (netgate.com)

vfs: drop the error parameter from vn_isdisk, introduce vn_isdisk_error

Most consumers pass NULL.

MFH

Sponsored by: Rubicon Communications, LLC (netgate.com)

Merge ^/head r363739 through r363986.

Unlocked getblk: Fix new false-positive assertion

A free buf's lock may be held (temporarily) due to unlocked lookup, so
buf_alloc() must acquire it without LK_NOWAIT. The unlocked getblk path
shou

Unlocked getblk: Fix new false-positive assertion

A free buf's lock may be held (temporarily) due to unlocked lookup, so
buf_alloc() must acquire it without LK_NOWAIT. The unlocked getblk path
should unlock it promptly once it realizes the identity does not match
the buffer it was searching for.

Reported by: gallatin
Reviewed by: kib
Tested by: pho
X-MFC-With: r363482
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D25914

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MFH

Sponsored by: Rubicon Communications, LLC (netgate.com)

Merge ^/head r363583 through r363738.

getblk: Remove a non-sensical LK_NOWAIT | LK_SLEEPFAIL

No functional change.

LK_SLEEPFAIL implies a behavior that is only possible if the lock operation can
sleep. LK_NOWAIT prevents the lock oper

getblk: Remove a non-sensical LK_NOWAIT | LK_SLEEPFAIL

No functional change.

LK_SLEEPFAIL implies a behavior that is only possible if the lock operation can
sleep. LK_NOWAIT prevents the lock operation from sleeping.

Discussed with: kib

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getblk: Avoid sleeping on wrong buf in lockless path

If the buffer identity changed during lookup, sleeping could introduce a
lock order reversal. Since we do not know if the identity changed until

getblk: Avoid sleeping on wrong buf in lockless path

If the buffer identity changed during lookup, sleeping could introduce a
lock order reversal. Since we do not know if the identity changed until we
get the lock, we must try-lock (LK_NOWAIT) only. EINTR and ERESTART error
handling becomes irrelevant, as we no longer sleep.

Reported by: kib
Reviewed by: kib
X-MFC-With: r363482
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D25898

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Use gbincore_unlocked for unprotected incore()

Reviewed by: markj
Sponsored by: Isilon
Differential Revision: https://reviews.freebsd.org/D25790

Add unlocked/SMR fast path to getblk()

Convert the bufobj tries to an SMR zone/PCTRIE and add a gbincore_unlocked()
API wrapping this functionality. Use it for a fast path in getblkx(),
falling bac

Add unlocked/SMR fast path to getblk()

Convert the bufobj tries to an SMR zone/PCTRIE and add a gbincore_unlocked()
API wrapping this functionality. Use it for a fast path in getblkx(),
falling back to locked lookup if we raced a thread changing the buf's
identity.

Reported by: Attilio
Reviewed by: kib, markj
Testing: pho (in progress)
Sponsored by: Isilon
Differential Revision: https://reviews.freebsd.org/D25782

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vfs: fix trivial whitespace issues which don't interefere with blame

.. even without the -w switch

This commit enables a UFS filesystem to do a forcible unmount when
the underlying media fails or becomes inaccessible. For example
when a USB flash memory card hosting a UFS filesystem is unplugged.

This commit enables a UFS filesystem to do a forcible unmount when
the underlying media fails or becomes inaccessible. For example
when a USB flash memory card hosting a UFS filesystem is unplugged.

The strategy for handling disk I/O errors when soft updates are
enabled is to stop writing to the disk of the affected file system
but continue to accept I/O requests and report that all future
writes by the file system to that disk actually succeed. Then
initiate an asynchronous forced unmount of the affected file system.

There are two cases for disk I/O errors:

- ENXIO, which means that this disk is gone and the lower layers
of the storage stack already guarantee that no future I/O to
this disk will succeed.

- EIO (or most other errors), which means that this particular
I/O request has failed but subsequent I/O requests to this
disk might still succeed.

For ENXIO, we can just clear the error and continue, because we
know that the file system cannot affect the on-disk state after we
see this error. For EIO or other errors, we arrange for the geom_vfs
layer to reject all future I/O requests with ENXIO just like is
done when the geom_vfs is orphaned. In both cases, the file system
code can just clear the error and proceed with the forcible unmount.

This new treatment of I/O errors is needed for writes of any buffer
that is involved in a dependency. Most dependencies are described
by a structure attached to the buffer's b_dep field. But some are
created and processed as a result of the completion of the dependencies
attached to the buffer.

Clearing of some dependencies require a read. For example if there
is a dependency that requires an inode to be written, the disk block
containing that inode must be read, the updated inode copied into
place in that buffer, and the buffer then written back to disk.

Often the needed buffer is already in memory and can be used. But
if it needs to be read from the disk, the read will fail, so we
fabricate a buffer full of zeroes and pretend that the read succeeded.
This zero'ed buffer can be updated and written back to disk.

The only case where a buffer full of zeros causes the code to do
the wrong thing is when reading an inode buffer containing an inode
that still has an inode dependency in memory that will reinitialize
the effective link count (i_effnlink) based on the actual link count
(i_nlink) that we read. To handle this case we now store the i_nlink
value that we wrote in the inode dependency so that it can be
restored into the zero'ed buffer thus keeping the tracking of the
inode link count consistent.

Because applications depend on knowing when an attempt to write
their data to stable storage has failed, the fsync(2) and msync(2)
system calls need to return errors if data fails to be written to
stable storage. So these operations return ENXIO for every call
made on files in a file system where we have otherwise been ignoring
I/O errors.

Coauthered by: mckusick
Reviewed by: kib
Tested by: Peter Holm
Approved by: mckusick (mentor)
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D24088

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buffer pager: skip bogus pages.

We cannot validate bogus page by reading a buffer.

PR: 244713
Reviewed by: glebius, markj
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Diffe

buffer pager: skip bogus pages.

We cannot validate bogus page by reading a buffer.

PR: 244713
Reviewed by: glebius, markj
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D24038

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Merge ^/head r358466 through r358677.

buffer pager: deref ucred immediately after read.

Ucred is passed to bread(9) so that non-local filesystems use proper
credentials. But, since clean buffer might be cached unless
buf_pager_relbuf i

buffer pager: deref ucred immediately after read.

Ucred is passed to bread(9) so that non-local filesystems use proper
credentials. But, since clean buffer might be cached unless
buf_pager_relbuf is not enabled, it makes credentials to have extra
reference until buffer is reclaimed. Ucred reference would prevent
jail from destroying if creds are jailed.

Dereferencing the read credentials on the valid buffer avoid that, and
should be fine because the buffer is valid and does not need re-read.

PR: 238032
Reported by: bz
Reproduced and tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D23775

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Merge ^/head r358400 through r358465.

Provide a lock free alternative to resolve bogus pages. This is not likely
to be much of a perf win, just a nice code simplification.

Reviewed by: markj, kib
Differential Revision: https://reviews.

Provide a lock free alternative to resolve bogus pages. This is not likely
to be much of a perf win, just a nice code simplification.

Reviewed by: markj, kib
Differential Revision: https://reviews.freebsd.org/D23866

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Convert a few triviail consumers to the new unlocked grab API.

Reviewed by: kib, markj
Differential Revision: https://reviews.freebsd.org/D23847

Add a blocking counter KPI.

refcount(9) was recently extended to support waiting on a refcount to
drop to zero, as this was needed for a lockless VM object
paging-in-progress counter. However, this

Add a blocking counter KPI.

refcount(9) was recently extended to support waiting on a refcount to
drop to zero, as this was needed for a lockless VM object
paging-in-progress counter. However, this adds overhead to all uses of
refcount(9) and doesn't really match traditional refcounting semantics:
once a counter has dropped to zero, the protected object may be freed at
any point and it is not safe to dereference the counter.

This change removes that extension and instead adds a new set of KPIs,
blockcount_*, for use by VM object PIP and busy.

Reviewed by: jeff, kib, mjg
Tested by: pho
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D23723

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Merge ^/head r357408 through r357661.