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  1. 06 3月, 2020 10 次提交
  3. 09 2月, 2020 3 次提交
    • H
      fs: Add VirtualBox guest shared folder (vboxsf) support · 0fd16957
      由 Hans de Goede 提交于 
      VirtualBox hosts can share folders with guests, this commit adds a
VFS driver implementing the Linux-guest side of this, allowing folders
exported by the host to be mounted under Linux.

This driver depends on the guest <-> host IPC functions exported by
the vboxguest driver.
Acked-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      0fd16957
    • L
      pipe: use exclusive waits when reading or writing · 0ddad21d
      由 Linus Torvalds 提交于 
      This makes the pipe code use separate wait-queues and exclusive waiting
for readers and writers, avoiding a nasty thundering herd problem when
there are lots of readers waiting for data on a pipe (or, less commonly,
lots of writers waiting for a pipe to have space).

While this isn't a common occurrence in the traditional "use a pipe as a
data transport" case, where you typically only have a single reader and
a single writer process, there is one common special case: using a pipe
as a source of "locking tokens" rather than for data communication.

In particular, the GNU make jobserver code ends up using a pipe as a way
to limit parallelism, where each job consumes a token by reading a byte
from the jobserver pipe, and releases the token by writing a byte back
to the pipe.

This pattern is fairly traditional on Unix, and works very well, but
will waste a lot of time waking up a lot of processes when only a single
reader needs to be woken up when a writer releases a new token.

A simplified test-case of just this pipe interaction is to create 64
processes, and then pass a single token around between them (this
test-case also intentionally passes another token that gets ignored to
test the "wake up next" logic too, in case anybody wonders about it):

    #include <unistd.h>

    int main(int argc, char **argv)
    {
        int fd[2], counters[2];

        pipe(fd);
        counters[0] = 0;
        counters[1] = -1;
        write(fd[1], counters, sizeof(counters));

        /* 64 processes */
        fork(); fork(); fork(); fork(); fork(); fork();

        do {
                int i;
                read(fd[0], &i, sizeof(i));
                if (i < 0)
                        continue;
                counters[0] = i+1;
                write(fd[1], counters, (1+(i & 1)) *sizeof(int));
        } while (counters[0] < 1000000);
        return 0;
    }

and in a perfect world, passing that token around should only cause one
context switch per transfer, when the writer of a token causes a
directed wakeup of just a single reader.

But with the "writer wakes all readers" model we traditionally had, on
my test box the above case causes more than an order of magnitude more
scheduling: instead of the expected ~1M context switches, "perf stat"
shows

        231,852.37 msec task-clock                #   15.857 CPUs utilized
        11,250,961      context-switches          #    0.049 M/sec
           616,304      cpu-migrations            #    0.003 M/sec
             1,648      page-faults               #    0.007 K/sec
 1,097,903,998,514      cycles                    #    4.735 GHz
   120,781,778,352      instructions              #    0.11  insn per cycle
    27,997,056,043      branches                  #  120.754 M/sec
       283,581,233      branch-misses             #    1.01% of all branches

      14.621273891 seconds time elapsed

       0.018243000 seconds user
       3.611468000 seconds sys

before this commit.

After this commit, I get

          5,229.55 msec task-clock                #    3.072 CPUs utilized
         1,212,233      context-switches          #    0.232 M/sec
           103,951      cpu-migrations            #    0.020 M/sec
             1,328      page-faults               #    0.254 K/sec
    21,307,456,166      cycles                    #    4.074 GHz
    12,947,819,999      instructions              #    0.61  insn per cycle
     2,881,985,678      branches                  #  551.096 M/sec
        64,267,015      branch-misses             #    2.23% of all branches

       1.702148350 seconds time elapsed

       0.004868000 seconds user
       0.110786000 seconds sys

instead. Much better.

[ Note! This kernel improvement seems to be very good at triggering a
  race condition in the make jobserver (in GNU make 4.2.1) for me. It's
  a long known bug that was fixed back in June 2017 by GNU make commit
  b552b0525198 ("[SV 51159] Use a non-blocking read with pselect to
  avoid hangs.").

  But there wasn't a new release of GNU make until 4.3 on Jan 19 2020,
  so a number of distributions may still have the buggy version. Some
  have backported the fix to their 4.2.1 release, though, and even
  without the fix it's quite timing-dependent whether the bug actually
  is hit. ]

Josh Triplett says:
 "I've been hammering on your pipe fix patch (switching to exclusive
  wait queues) for a month or so, on several different systems, and I've
  run into no issues with it. The patch *substantially* improves
  parallel build times on large (~100 CPU) systems, both with parallel
  make and with other things that use make's pipe-based jobserver.

  All current distributions (including stable and long-term stable
  distributions) have versions of GNU make that no longer have the
  jobserver bug"
Tested-by: NJosh Triplett <josh@joshtriplett.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      0ddad21d
    • A
      compat_ioctl: fix FIONREAD on devices · 0a061743
      由 Arnd Bergmann 提交于 
      My final cleanup patch for sys_compat_ioctl() introduced a regression on
the FIONREAD ioctl command, which is used for both regular and special
files, but only works on regular files after my patch, as I had missed
the warning that Al Viro put into a comment right above it.

Change it back so it can work on any file again by moving the implementation
to do_vfs_ioctl() instead.

Fixes: 77b90401 ("compat_ioctl: simplify the implementation")
Reported-and-tested-by: NChristian Zigotzky <chzigotzky@xenosoft.de>
Reported-and-tested-by: Nyouling257 <youling257@gmail.com>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
      0a061743
  5. 08 2月, 2020 17 次提交
  7. 07 2月, 2020 10 次提交
    • D
      fs: New zonefs file system · 8dcc1a9d
      由 Damien Le Moal 提交于 
      zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).

As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.

Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.

The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
   under a common sub-directory:
     * For conventional zones, the sub-directory "cnv" is used.
     * For sequential write zones, the sub-directory "seq" is used.
  These two directories are the only directories that exist in zonefs.
  Users cannot create other directories and cannot rename nor delete
  the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
   type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
   Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
   pointer position relative to the zone start sector. Truncating these
   files is allowed only down to 0, in which case, the zone is reset to
   rewind the zone write pointer position to the start of the zone, or
   up to the zone size, in which case the file's zone is transitioned
   to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
   file zone size. Any access exceeding the zone size is failed with
   the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
   sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
   that can be issued to conventional zone files. Buffered, direct and
   mmap read & write operations are accepted. For sequential zone files,
   there are no restrictions on read operations, but all write
   operations must be direct IO append writes. mmap write of sequential
   files is not allowed.

Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
  zones can be aggregated into a single larger file instead of the
  default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
  (root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
  changed.

The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:

git@github.com:damien-lemoal/zonefs-tools.git.

zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.

Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.

$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root     1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq

The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).

$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0

This aggregated conventional zone file can be used as a regular file.

$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data

The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.

$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355

For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.

$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s

$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0

The written file can be truncated to the zone size, preventing any
further write operation.

$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0

Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.

$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0

Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.

$ stat /mnt/seq/0
  File: /mnt/seq/0
  Size: 0       Blocks: 524288     IO Block: 4096   regular empty file
Device: 870h/2160d      Inode: 50431       Links: 1
Access: (0640/-rw-r-----)  Uid: (    0/    root)   Gid: (    0/  root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
 Birth: -

The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.

This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: NDamien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: NDave Chinner <dchinner@redhat.com>
      8dcc1a9d
    • A
      fold struct fs_parameter_enum into struct constant_table · 5eede625
      由 Al Viro 提交于 
      no real difference now
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      5eede625
    • A
      fs_parse: get rid of ->enums · 2710c957
      由 Al Viro 提交于 
      Don't do a single array; attach them to fsparam_enum() entry
instead.  And don't bother trying to embed the names into those -
it actually loses memory, with no real speedup worth mentioning.

Simplifies validation as well.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      2710c957
    • A
      Pass consistent param->type to fs_parse() · 0f89589a
      由 Al Viro 提交于 
      As it is, vfs_parse_fs_string() makes "foo" and "foo=" indistinguishable;
both get fs_value_is_string for ->type and NULL for ->string.  To make
it even more unpleasant, that combination is impossible to produce with
fsconfig().

Much saner rules would be
        "foo"           => fs_value_is_flag, NULL
	"foo="          => fs_value_is_string, ""
	"foo=bar"       => fs_value_is_string, "bar"
All cases are distinguishable, all results are expressable by fsconfig(),
->has_value checks are much simpler that way (to the point of the field
being useless) and quite a few regressions go away (gfs2 has no business
accepting -o nodebug=, for example).

Partially based upon patches from Miklos.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      0f89589a
    • S
      smb3: Add defines for new information level, FileIdInformation · 51d92d69
      由 Steve French 提交于 
      See MS-FSCC 2.4.43.  Valid to be quried from most
Windows servers (among others).
Signed-off-by: NSteve French <stfrench@microsoft.com>
Reviewed-by: NAurelien Aptel <aaptel@suse.com>
      51d92d69
    • S
      smb3: print warning once if posix context returned on open · ab3459d8
      由 Steve French 提交于 
      SMB3.1.1 POSIX Context processing is not complete yet - so print warning
(once) if server returns it on open.
Signed-off-by: NSteve French <stfrench@microsoft.com>
Reviewed-by: NAurelien Aptel <aaptel@suse.com>
      ab3459d8
    • S
      smb3: add one more dynamic tracepoint missing from strict fsync path · 2391ca41
      由 Steve French 提交于 
      We didn't have a dynamic trace point for catching errors in
file_write_and_wait_range error cases in cifs_strict_fsync.

Since not all apps check for write behind errors, it can be
important for debugging to be able to trace these error
paths.
Suggested-and-reviewed-by: NPavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>
      2391ca41
    • A
      cifs: fix mode bits from dir listing when mounted with modefromsid · e3e056c3
      由 Aurelien Aptel 提交于 
      When mounting with -o modefromsid, the mode bits are stored in an
ACE. Directory enumeration (e.g. ls -l /mnt) triggers an SMB Query Dir
which does not include ACEs in its response. The mode bits in this
case are silently set to a default value of 755 instead.

This patch marks the dentry created during the directory enumeration
as needing re-evaluation (i.e. additional Query Info with ACEs) so
that the mode bits can be properly extracted.

Quick repro:

$ mount.cifs //win19.test/data /mnt -o ...,modefromsid
$ touch /mnt/foo && chmod 751 /mnt/foo
$ stat /mnt/foo
  # reports 751 (OK)
$ sleep 2
  # dentry older than 1s by default get invalidated
$ ls -l /mnt
  # since dentry invalid, ls does a Query Dir
  # and reports foo as 755 (WRONG)
Signed-off-by: NAurelien Aptel <aaptel@suse.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>
CC: Stable <stable@vger.kernel.org>
Reviewed-by: NPavel Shilovsky <pshilov@microsoft.com>
      e3e056c3
    • A
      cifs: fix channel signing · cc95b677
      由 Aurelien Aptel 提交于 
      The server var was accidentally used as an iterator over the global
list of connections, thus overwritten the passed argument. This
resulted in the wrong signing key being returned for extra channels.

Fix this by using a separate var to iterate.
Signed-off-by: NAurelien Aptel <aaptel@suse.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>
Reviewed-by: NPaulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: NPavel Shilovsky <pshilov@microsoft.com>
      cc95b677
    • A
      gfs2: fix O_SYNC write handling · 6e5e41e2
      由 Andreas Gruenbacher 提交于 
      In gfs2_file_write_iter, for direct writes, the error checking in the buffered
write fallback case is incomplete.  This can cause inode write errors to go
undetected.  Fix and clean up gfs2_file_write_iter along the way.

Based on a proposed fix by Christoph Hellwig <hch@lst.de>.

Fixes: 967bcc91 ("gfs2: iomap direct I/O support")
Cc: stable@vger.kernel.org # v4.19+
Signed-off-by: NAndreas Gruenbacher <agruenba@redhat.com>
      6e5e41e2