linux/fs/btrfs
Sage Weil 462045928b Btrfs: add START_SYNC, WAIT_SYNC ioctls
START_SYNC will start a sync/commit, but not wait for it to
complete.  Any modification started after the ioctl returns is
guaranteed not to be included in the commit.  If a non-NULL
pointer is passed, the transaction id will be returned to
userspace.

WAIT_SYNC will wait for any in-progress commit to complete.  If a
transaction id is specified, the ioctl will block and then
return (success) when the specified transaction has committed.
If it has already committed when we call the ioctl, it returns
immediately.  If the specified transaction doesn't exist, it
returns EINVAL.

If no transaction id is specified, WAIT_SYNC will wait for the
currently committing transaction to finish it's commit to disk.
If there is no currently committing transaction, it returns
success.

These ioctls are useful for applications which want to impose an
ordering on when fs modifications reach disk, but do not want to
wait for the full (slow) commit process to do so.

Picky callers can take the transid returned by START_SYNC and
feed it to WAIT_SYNC, and be certain to wait only as long as
necessary for the transaction _they_ started to reach disk.

Sloppy callers can START_SYNC and WAIT_SYNC without a transid,
and provided they didn't wait too long between the calls, they
will get the same result.  However, if a second commit starts
before they call WAIT_SYNC, they may end up waiting longer for
it to commit as well.  Even so, a START_SYNC+WAIT_SYNC still
guarantees that any operation completed before the START_SYNC
reaches disk.

Signed-off-by: Sage Weil <sage@newdream.net>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-10-29 15:41:32 -04:00
..
acl.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable 2010-06-11 14:18:47 -07:00
async-thread.c Btrfs: don't walk around with task->state != TASK_RUNNING 2010-05-25 10:34:58 -04:00
async-thread.h
btrfs_inode.h Btrfs: Metadata reservation for orphan inodes 2010-05-25 10:34:52 -04:00
compat.h
compression.c Btrfs: cleanup warnings from gcc 4.6 (nonbugs) 2010-10-29 15:14:37 -04:00
compression.h
ctree.c Btrfs: cleanup warnings from gcc 4.6 (nonbugs) 2010-10-29 15:14:37 -04:00
ctree.h Btrfs: async transaction commit 2010-10-29 15:37:34 -04:00
delayed-ref.c Btrfs: Integrate metadata reservation with start_transaction 2010-05-25 10:34:50 -04:00
delayed-ref.h Btrfs: Integrate metadata reservation with start_transaction 2010-05-25 10:34:50 -04:00
dir-item.c Btrfs: Fix variables set but not read (bugs found by gcc 4.6) 2010-10-29 15:14:31 -04:00
disk-io.c Btrfs: async transaction commit 2010-10-29 15:37:34 -04:00
disk-io.h Btrfs: use async helpers for DIO write checksumming 2010-05-25 10:34:58 -04:00
export.c Btrfs: change how we mount subvolumes 2010-03-15 10:58:13 -04:00
export.h
extent_io.c Btrfs: cleanup warnings from gcc 4.6 (nonbugs) 2010-10-29 15:14:37 -04:00
extent_io.h Btrfs: Switch the extent buffer rbtree into a radix tree 2010-10-29 11:25:45 -04:00
extent_map.c Btrfs: Use ERR_CAST helpers 2010-10-29 15:14:23 -04:00
extent_map.h
extent-tree.c Btrfs: drop unused variable in block_alloc_rsv 2010-10-29 15:17:41 -04:00
file-item.c Btrfs: add basic DIO read/write support 2010-05-25 10:34:57 -04:00
file.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable 2010-06-11 14:18:47 -07:00
free-space-cache.c Btrfs: Add a clear_cache mount option 2010-10-29 09:26:36 -04:00
free-space-cache.h Btrfs: load free space cache if it exists 2010-10-29 09:26:35 -04:00
hash.h
inode-item.c Btrfs: Integrate metadata reservation with start_transaction 2010-05-25 10:34:50 -04:00
inode-map.c
inode.c Btrfs: cleanup warnings from gcc 4.6 (nonbugs) 2010-10-29 15:14:37 -04:00
ioctl.c Btrfs: add START_SYNC, WAIT_SYNC ioctls 2010-10-29 15:41:32 -04:00
ioctl.h Btrfs: add START_SYNC, WAIT_SYNC ioctls 2010-10-29 15:41:32 -04:00
Kconfig
locking.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
locking.h
Makefile
ordered-data.c Btrfs: cleanup warnings from gcc 4.6 (nonbugs) 2010-10-29 15:14:37 -04:00
ordered-data.h Btrfs: add basic DIO read/write support 2010-05-25 10:34:57 -04:00
orphan.c
print-tree.c
print-tree.h
ref-cache.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
ref-cache.h Btrfs: use RB_ROOT to intialize rb_trees instead of setting rb_node to NULL 2010-03-08 16:26:50 -05:00
relocation.c Btrfs: Fix variables set but not read (bugs found by gcc 4.6) 2010-10-29 15:14:31 -04:00
root-tree.c Btrfs: cleanup warnings from gcc 4.6 (nonbugs) 2010-10-29 15:14:37 -04:00
struct-funcs.c
super.c Btrfs: cleanup warnings from gcc 4.6 (nonbugs) 2010-10-29 15:14:37 -04:00
sysfs.c Driver core: Constify struct sysfs_ops in struct kobj_type 2010-03-07 17:04:49 -08:00
transaction.c Btrfs: add START_SYNC, WAIT_SYNC ioctls 2010-10-29 15:41:32 -04:00
transaction.h Btrfs: add START_SYNC, WAIT_SYNC ioctls 2010-10-29 15:41:32 -04:00
tree-defrag.c Btrfs: cleanup warnings from gcc 4.6 (nonbugs) 2010-10-29 15:14:37 -04:00
tree-log.c Btrfs: cleanup warnings from gcc 4.6 (nonbugs) 2010-10-29 15:14:37 -04:00
tree-log.h Btrfs: Metadata ENOSPC handling for tree log 2010-05-25 10:34:53 -04:00
version.h
version.sh
volumes.c Btrfs: cleanup warnings from gcc 4.6 (nonbugs) 2010-10-29 15:14:37 -04:00
volumes.h
xattr.c Btrfs: cleanup warnings from gcc 4.6 (nonbugs) 2010-10-29 15:14:37 -04:00
xattr.h btrfs: constify xattr_handler 2010-05-21 18:31:18 -04:00
zlib.c Btrfs: cleanup warnings from gcc 4.6 (nonbugs) 2010-10-29 15:14:37 -04:00