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author | Li Zefan <lizf@cn.fujitsu.com> | 2011-04-20 02:06:11 (GMT) |
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committer | Li Zefan <lizf@cn.fujitsu.com> | 2011-04-25 08:46:04 (GMT) |
commit | 581bb050941b4f220f84d3e5ed6dace3d42dd382 (patch) | |
tree | 5ebd56af5eb3612f508419b188dfc18e959e7c94 /kernel/sched_stats.h | |
parent | 34d52cb6c50b5a43901709998f59fb1c5a43dc4a (diff) | |
download | linux-fsl-qoriq-581bb050941b4f220f84d3e5ed6dace3d42dd382.tar.xz |
Btrfs: Cache free inode numbers in memory
Currently btrfs stores the highest objectid of the fs tree, and it always
returns (highest+1) inode number when we create a file, so inode numbers
won't be reclaimed when we delete files, so we'll run out of inode numbers
as we keep create/delete files in 32bits machines.
This fixes it, and it works similarly to how we cache free space in block
cgroups.
We start a kernel thread to read the file tree. By scanning inode items,
we know which chunks of inode numbers are free, and we cache them in
an rb-tree.
Because we are searching the commit root, we have to carefully handle the
cross-transaction case.
The rb-tree is a hybrid extent+bitmap tree, so if we have too many small
chunks of inode numbers, we'll use bitmaps. Initially we allow 16K ram
of extents, and a bitmap will be used if we exceed this threshold. The
extents threshold is adjusted in runtime.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Diffstat (limited to 'kernel/sched_stats.h')
0 files changed, 0 insertions, 0 deletions