Re: Integration branch pushed out to btrfs-unstable

[Sergei Trofimovich <slyfox@gentoo.org>]

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> > The commit
> > 
> > commit c4f675cd40d955d539180506c09515c90169b15b
> > Author: Sergei Trofimovich <slyfox@gentoo.org>
> > Date:   Fri May 20 20:20:30 2011 +0000
> > 
> >     btrfs: don't spin in shrink_delalloc if there is nothing to free
> > 
> > gives me very early ENOSPC in my tests on a small volume (7GB).
> 
> What king of test is that? I'd like to reproduce it.
> Does it do a lot of parallel I/O?
> 
> May I ask you to try to reproduce the problem with this sole patch
> on top of linus master?

With Arne's params to fs_mark it triggers for 2.6.39+this patch.
I took 2GB loop device and the script [1].

$ ./make_it.sh
...
#  /home/slyfox/dev/fs_mark/fs_mark  -D  512  -t  16  -n  4096  -s  51200  -L7  -S0  -d  /mnt/ut 
#       Version 3.3, 16 thread(s) starting at Wed May 25 23:35:06 2011
#       Sync method: NO SYNC: Test does not issue sync() or fsync() calls.
#       Directories:  Time based hash between directories across 512 subdirectories with 180 seconds per subdirectory.
#       File names: 40 bytes long, (16 initial bytes of time stamp with 24 random bytes at end of name)
#       Files info: size 51200 bytes, written with an IO size of 16384 bytes per write
#       App overhead is time in microseconds spent in the test not doing file writing related system calls.

FSUse%        Count         Size    Files/sec     App Overhead
fs_mark: write_file write failed: -1 No space left on device
fs_mark: write_file write failed: -1 No space left on device
fs_mark: write_file write failed: -1 No space left on device
...^C

$ .../btrfs fi df /mnt/ut/
Data: total=622.25MB, used=434.61MB
System: total=4.00MB, used=4.00KB
Metadata: total=417.50MB, used=6.69MB

$ sudo .../btrfs fi show /dev/loop0
Label: none  uuid: ccb18c12-4cbe-458c-835a-30e767939121
        Total devices 1 FS bytes used 441.31MB
        devid    1 size 2.00GB used 1.02GB path /dev/loop0

[1] 'make_it.sh' script exposing bug:
    export LANG=C

    FS_MARK=$HOME/dev/fs_mark/fs_mark
    MKFS_BTRFS=$HOME/dev/git/btrfs-progs-unstable/mkfs.btrfs

    sz=2
    the_file=${sz}G.img
    mount_point=/mnt/ut

    dd if=/dev/zero of="${the_file}" bs=1 count=1 seek=$((${sz}*1024*1024*1024-1))
    $MKFS_BTRFS -d raid0 -m raid0 "${the_file}"
    sudo mount -oloop "${the_file}" "${mount_point}"
    sudo chown slyfox:users "${mount_point}"
    chmod u+w "${mount_point}"
    cd /tmp
    $FS_MARK \
        -D  512  -t  16  -n  4096  -s  51200  -L7  -S0 \
        -d "${mount_point}"
    sudo umount "${mount_point}"

-- 

  Sergei

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