Revert "Add new kstat for monitoring time in dmu_tx_assign"

This reverts commit 92334b14ec378b1693573b52c09816bbade9cf3e.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Revert "Add txgs-<pool> kstat file"

This reverts commit e95853a331529a6cb96fdf10476c53441e59f4e1.
Add visibility in to arc_read

This change is an attempt to add visibility into the arc_read calls
occurring on a system, in real time. To do this, a list was added to the
in memory SPA data structure for a pool, with each element on the list
corresponding to a call to arc_read. These entries are then exported
through the kstat interface, which can then be interpreted in userspace.

For each arc_read call, the following information is exported:

 * A unique identifier (uint64_t)
 * The time the entry was added to the list (hrtime_t)
   (*not* wall clock time; relative to the other entries on the list)
 * The objset ID (uint64_t)
 * The object number (uint64_t)
 * The indirection level (uint64_t)
 * The block ID (uint64_t)
 * The name of the function originating the arc_read call (char[24])
 * The arc_flags from the arc_read call (uint32_t)
 * The PID of the reading thread (pid_t)
 * The command or name of thread originating read (char[16])

From this exported information one can see, in real time, exactly what
is being read, what function is generating the read, and whether or not
the read was found to be already cached.

There is still some work to be done, but this should serve as a good
starting point.

Specifically, dbuf_read's are not accounted for in the currently
exported information. Thus, a follow up patch should probably be added
to export these calls that never call into arc_read (they only hit the
dbuf hash table). In addition, it might be nice to create a utility
similar to "arcstat.py" to digest the exported information and display
it in a more readable format. Or perhaps, log the information and allow
for it to be "replayed" at a later time.

Signed-off-by: Prakash Surya <surya1@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Add visibility in to txg sync behavior

This change is an attempt to add visibility in to how txgs are being
formed on a system, in real time. To do this, a list was added to the
in memory SPA data structure for a pool, with each element on the list
corresponding to txg. These entries are then exported through the kstat
interface, which can then be interpreted in userspace.

For each txg, the following information is exported:

 * Unique txg number (uint64_t)
 * The time the txd was born (hrtime_t)
   (*not* wall clock time; relative to the other entries on the list)
 * The current txg state ((O)pen/(Q)uiescing/(S)yncing/(C)ommitted)
 * The number of reserved bytes for the txg (uint64_t)
 * The number of bytes read during the txg (uint64_t)
 * The number of bytes written during the txg (uint64_t)
 * The number of read operations during the txg (uint64_t)
 * The number of write operations during the txg (uint64_t)
 * The time the txg was closed (hrtime_t)
 * The time the txg was quiesced (hrtime_t)
 * The time the txg was synced (hrtime_t)

Note that while the raw kstat now stores relative hrtimes for the
open, quiesce, and sync times.  Those relative times are used to
calculate how long each state took and these deltas and printed by
output handlers.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Add visibility in to dmu_tx_assign times

This change adds a new kstat to gain some visibility into the
amount of time spent in each call to dmu_tx_assign. A histogram
is exported via the new dmu_tx_assign file. The information
contained in this histogram is the frequency dmu_tx_assign
took to complete given an interval range.

Signed-off-by: Prakash Surya <surya1@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Add visibility in to cached dbufs

Currently there is no mechanism to inspect which dbufs are being
cached by the system.  There are some coarse counters in arcstats
by they only give a rough idea of what's being cached.  This patch
aims to improve the current situation by adding a new dbufs kstat.

When read this new kstat will walk all cached dbufs linked in to
the dbuf_hash.  For each dbuf it will dump detailed information
about the buffer.  It will also dump additional information about
the referenced arc buffer and its related dnode.  This provides a
more complete view in to exactly what is being cached.

With this generic infrastructure in place utilities can be written
to post-process the data to understand exactly how the caching is
working.  For example, the data could be processed to show a list
of all cached dnodes and how much space they're consuming.  Or a
similar list could be generated based on dnode type.  Many other
ways to interpret the data exist based on what kinds of questions
you're trying to answer.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Prakash Surya <surya1@llnl.gov>
Add dbufstat.py command

The dbufstat.py command was added to provide a conveniant way to
easily determine what ZFS is caching.  The script consumes the
raw /proc/spl/kstat/zfs/dbufs kstat data can consolidates it in
to a more human readable form.  This was designed primarily as
a tool to aid developers but it may also be useful for advanced
users who want more visibility in to what the ARC is caching.

When run without options dbufstat.py will default to showing a
list of all objects with at least one buffer present in the
cache.  The total cache space consumed by that object will be
printed on the right along with the object type.  Similar to the
arcstats.py command the -x option may used to display additional
fields.

Two other modes of operation are also supported by dbufstat.py
and the expectation is additional display modes may be added as
needed.  The -t option will summerize the total number of bytes
cached for each object type, and the -b option will show every
dbuf currently cached.

The script was designed to be consistent with arcstat.py and
includes most of the same options and funcationality.

Signed-off-by: Prakash Surya <surya1@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Merge branch 'kstat'

This branch updates several of the zfs kstats to take advantage
of the improved raw kstat functionality.  In addition, two new
kstats and a script called dbufstat.py are introduced.

Updated+New Kstats
* dbufs        - Stats for all dbufs in the dbuf_hash
* <pool>/txgs  - Stats for the last N txgs synced to disk
* <pool>/reads - Stats for rhe last N reads issues by the ARC
* <pool>/dmu_tx_assign - Histogram of tx assign times

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Corrected "zfs list -t <type>" syntax

in man page and in command help.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1805
Introduce zpool_get_prop_literal interface

This change introduces zpool_get_prop_literal. It's an expanded version
of zpool_get_prop taking one additional boolean parameter. With this
parameter set to B_FALSE it will behave identically to zpool_get_prop.
Setting it to B_TRUE will return full precision numbers for the
following properties:

ZPOOL_PROP_SIZE
ZPOOL_PROP_ALLOCATED
ZPOOL_PROP_FREE
ZPOOL_PROP_FREEING
ZPOOL_PROP_EXPANDSZ
ZPOOL_PROP_ASHIFT

Also introduced is a wrapper function for zpool_get_prop making it
use zpool_get_prop_literal in the background.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #1813
Add -p switch to "zpool get"

This works the same as the -p switch to "zfs get", displaying full
resolution values for appropriate attributes.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1813
Restructure zfs_readdir() to fix regressions

This does the following:

1. It creates a uint8_t type value, which is initialized to DT_DIR on
dot directories and ZFS_DIRENT_TYPE(zap.za_first_integer) otherwise.
This resolves a regression where we return unintialized values as the
directory entry type on dot directories. This was accidentally
introduced by commit 8170d281263e52ff33d7fba93ab625196844df36.

2. It restructures zfs_readdir() code to use `uint64_t offset` like
Illumos instead of `loff_t *pos`. This resolves a regression where
negative ZAP cursors were treated as if they were dot directories.

3. It restructures the function to more closely match the structure of
zfs_readdir() on Illumos and removes the unused variable outcount, which
was only used on Illumos.

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1750
Add script to fix file names in upstream patches

Added a simple sed script to do a search and replace on the Illumos
ZFS file names and replace them with the ZFS on Linux equivalent.

Example usage:

    # Replace Illumos paths with Linux paths
    $ ./scripts/zfs2zol-patch.sed arc.c.patch > arc.c.patch.linux

    # Ensure the script worked as expected
    $ diff arc.c.patch arc.c.patch.linux

    # Apply the patch using Linux paths
    $ patch -p1 < arc.c.patch.linux

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Prakash Surya <surya1@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1679
Prevent xattr remove from creating xattr directory

Attempting to remove an xattr from a file which does not contain
any directory based xattrs would result in the xattr directory
being created.  This behavior is non-optimal because it results
in write operations to the pool in addition to the expected error
being returned.

To prevent this the CREATE_XATTR_DIR flag is only passed in
zpl_xattr_set_dir() when setting a non-NULL xattr value.  In
addition, zpl_xattr_set() is updated similarly such that it will
return immediately if passed an xattr name which doesn't exist
and a NULL value.

Signed-off-by: Massimo Maggi <me@massimo-maggi.eu>
Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #170
Improve xattr property documentation

Extend the xattr property section of zfs(8) such that it covers
both styles of supported xattr.  A short discussion of the benefits
and drawbacks of each type is presented to allow users to make an
informed choice.

Signed-off-by: Massimo Maggi <me@massimo-maggi.eu>
Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #170
Posix ACL Support

This change adds support for Posix ACLs by storing them as an xattr
which is common practice for many Linux file systems.  Since the
Posix ACL is stored as an xattr it will not overwrite any existing
ZFS/NFSv4 ACLs which may have been set.  The Posix ACL will also
be non-functional on other platforms although it may be visible
as an xattr if that platform understands SA based xattrs.

By default Posix ACLs are disabled but they may be enabled with
the new 'aclmode=noacl|posixacl' property.  Set the property to
'posixacl' to enable them.  If ZFS/NFSv4 ACL support is ever added
an appropriate acltype will be added.

This change passes the POSIX Test Suite cleanly with the exception
of xacl/00.t test 45 which is incorrect for Linux (Ext4 fails too).

  http://www.tuxera.com/community/posix-test-suite/

Signed-off-by: Massimo Maggi <me@massimo-maggi.eu>
Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #170
Reintroduce uio_prefaultpages()

This was accidentally removed by overzealous commenting.

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #1775
Fix order of function calls in zio_free_sync()

The resolution of a merge conflict when merging Illumos #3464 caused us
to invert the order couple of function calls in zio_free_sync() versus
what they are in Illumos.

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #1775
Fix incorrect usage of strdup() in zfs_unmount_snap()

Modifying the length of a string returned by strdup() is incorrect
because strfree() is allowed to use strlen() to determine which slab
cache was used to do the allocation.

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #1775
Add missing copyright notices from Illumos

This resolves merge conflicts when merging Illumos #3588 and Illumos #4047.

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #1775