ext4: Add sysfs support
Add basic sysfs support so that information about the mounted
filesystem and various tuning parameters can be accessed via
/sys/fs/ext4/<dev>/*.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/Documentation/ABI/testing/sysfs-fs-ext4 b/Documentation/ABI/testing/sysfs-fs-ext4
new file mode 100644
index 0000000..4e79074
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+++ b/Documentation/ABI/testing/sysfs-fs-ext4
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+What: /sys/fs/ext4/<disk>/mb_stats
+Date: March 2008
+Contact: "Theodore Ts'o" <tytso@mit.edu>
+Description:
+ Controls whether the multiblock allocator should
+ collect statistics, which are shown during the unmount.
+ 1 means to collect statistics, 0 means not to collect
+ statistics
+
+What: /sys/fs/ext4/<disk>/mb_group_prealloc
+Date: March 2008
+Contact: "Theodore Ts'o" <tytso@mit.edu>
+Description:
+ The multiblock allocator will round up allocation
+ requests to a multiple of this tuning parameter if the
+ stripe size is not set in the ext4 superblock
+
+What: /sys/fs/ext4/<disk>/mb_max_to_scan
+Date: March 2008
+Contact: "Theodore Ts'o" <tytso@mit.edu>
+Description:
+ The maximum number of extents the multiblock allocator
+ will search to find the best extent
+
+What: /sys/fs/ext4/<disk>/mb_min_to_scan
+Date: March 2008
+Contact: "Theodore Ts'o" <tytso@mit.edu>
+Description:
+ The minimum number of extents the multiblock allocator
+ will search to find the best extent
+
+What: /sys/fs/ext4/<disk>/mb_order2_req
+Date: March 2008
+Contact: "Theodore Ts'o" <tytso@mit.edu>
+Description:
+ Tuning parameter which controls the minimum size for
+ requests (as a power of 2) where the buddy cache is
+ used
+
+What: /sys/fs/ext4/<disk>/mb_stream_req
+Date: March 2008
+Contact: "Theodore Ts'o" <tytso@mit.edu>
+Description:
+ Files which have fewer blocks than this tunable
+ parameter will have their blocks allocated out of a
+ block group specific preallocation pool, so that small
+ files are packed closely together. Each large file
+ will have its blocks allocated out of its own unique
+ preallocation pool.
+
+What: /sys/fs/ext4/<disk>/inode_readahead
+Date: March 2008
+Contact: "Theodore Ts'o" <tytso@mit.edu>
+Description:
+ Tuning parameter which controls the maximum number of
+ inode table blocks that ext4's inode table readahead
+ algorithm will pre-read into the buffer cache
+
+What: /sys/fs/ext4/<disk>/delayed_allocation_blocks
+Date: March 2008
+Contact: "Theodore Ts'o" <tytso@mit.edu>
+Description:
+ This file is read-only and shows the number of blocks
+ that are dirty in the page cache, but which do not
+ have their location in the filesystem allocated yet.
+
+What: /sys/fs/ext4/<disk>/lifetime_write_kbytes
+Date: March 2008
+Contact: "Theodore Ts'o" <tytso@mit.edu>
+Description:
+ This file is read-only and shows the number of kilobytes
+ of data that have been written to this filesystem since it was
+ created.
+
+What: /sys/fs/ext4/<disk>/session_write_kbytes
+Date: March 2008
+Contact: "Theodore Ts'o" <tytso@mit.edu>
+Description:
+ This file is read-only and shows the number of
+ kilobytes of data that have been written to this
+ filesystem since it was mounted.