1
linux/fs/sysfs
Dan Williams 2424b5dd06 sysfs: refill attribute buffer when reading from offset 0
Requiring userspace to close and re-open sysfs attributes has been the
policy since before 2.6.12.  It allows userspace to get a consistent
snapshot of kernel state and consume it with incremental reads and seeks.

Now, if the file position is zero the kernel assumes userspace wants to see
the new value.  The application for this change is to allow a userspace
RAID metadata handler to check the state of an array without causing any
memory allocations.  Thus not causing writeback to a raid array that might
be blocked waiting for userspace to take action.

Cc: Neil Brown <neilb@suse.de>
Acked-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-04-19 19:10:29 -07:00
..
bin.c sysfs: add copyrights 2007-10-12 14:51:12 -07:00
dir.c SYSFS: Explicitly include required header file slab.h. 2008-04-19 19:10:27 -07:00
file.c sysfs: refill attribute buffer when reading from offset 0 2008-04-19 19:10:29 -07:00
group.c sysfs: remove BUG_ON() from sysfs_remove_group() 2008-02-07 11:31:46 -08:00
inode.c mm: bdi init hooks 2007-10-17 08:42:45 -07:00
Makefile
mount.c mm: bdi init hooks 2007-10-17 08:42:45 -07:00
symlink.c sysfs: Allow removal of symlinks in the sysfs root 2008-04-18 08:56:10 -07:00
sysfs.h sysfs: make sysfs_{get,put}_active() static 2007-10-30 21:52:33 -07:00