The timeout feature is added to "freeze ioctl" to solve a deadlock
when the freezer accesses a frozen filesystem. And new ioctl
to reset the timeout period is added to extend the timeout period.
For example, the freezer resets the timeout period to 10 seconds every 5
seconds. In this approach, even if the freezer causes a deadlock by
accessing the frozen filesystem, it will be solved by the timeout
in 10 seconds and the freezer will be able to recognize that
at the next reset of timeout period.
o Freeze the filesystem
int ioctl(int fd, int FIFREEZE, long *timeout_sec)
fd: The file descriptor of the mountpoint
FIFREEZE: request code for the freeze
timeout_sec: the timeout period in seconds
If it's 0 or 1, the timeout isn't set.
This special case of "1" is implemented to keep
the compatibility with XFS applications.
Return value: 0 if the operation succeeds. Otherwise, -1
o Reset the timeout period
int ioctl(int fd, int FIFREEZE_RESET_TIMEOUT, long *timeout_sec)
fd:file descriptor of mountpoint
FIFREEZE_RESET_TIMEOUT: request code for reset of timeout period
timeout_sec: new timeout period in seconds
Return value: 0 if the operation succeeds. Otherwise, -1
Error number: If the filesystem has already been unfrozen,
errno is set to EINVAL.
Signed-off-by: Takashi Sato <t-sato@yk.jp.nec.com>
Signed-off-by: Masayuki Hamaguchi <m-hamaguchi@ys.jp.nec.com>
---
drivers/md/dm.c | 2 -
fs/block_dev.c | 2 +
fs/buffer.c | 44 ++++++++++++++++++++++++---
fs/ioctl.c | 71 ++++++++++++++++++++++++++++++++++++++++++--
fs/super.c | 37 ++++++++++++++++++++++
fs/xfs/xfs_fsops.c | 2 -
include/linux/buffer_head.h | 4 +-
include/linux/fs.h | 8 ++++
8 files changed, 159 insertions(+), 11 deletions(-)
diff -uprN -X linux-2.6.27-rc5.org/Documentation/dontdiff ...
