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ocfs2: POSIX file locks support

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This is actually pretty easy since fs/dlm already handles the bulk of the
work. The Ocfs2 userspace cluster stack module already uses fs/dlm as the
underlying lock manager, so I only had to add the right calls.

Cluster-aware POSIX locks ("plocks") can be turned off by the same means at
UNIX locks - mount with 'noflocks', or create a local-only Ocfs2 volume.
Internally, the file system uses two sets of file_operations, depending on
whether cluster aware plocks is required. This turns out to be easier than
implementing local-only versions of ->lock.

Signed-off-by: Mark Fasheh <mfasheh@suse.com>
This commit is contained in:
Mark Fasheh
2008-07-21 14:29:16 -07:00
parent a447c09324
commit 53da4939f3
8 changed files with 155 additions and 3 deletions
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53
fs/ocfs2/file.c
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@@ -2237,6 +2237,10 @@ const struct inode_operations ocfs2_special_file_iops = {
.permission = ocfs2_permission,
};
/*
* Other than ->lock, keep ocfs2_fops and ocfs2_dops in sync with
* ocfs2_fops_no_plocks and ocfs2_dops_no_plocks!
*/
const struct file_operations ocfs2_fops = {
.llseek = generic_file_llseek,
.read = do_sync_read,
@@ -2250,13 +2254,60 @@ const struct file_operations ocfs2_fops = {
.unlocked_ioctl = ocfs2_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = ocfs2_compat_ioctl,
#endif
.lock = ocfs2_lock,
.flock = ocfs2_flock,
.splice_read = ocfs2_file_splice_read,
.splice_write = ocfs2_file_splice_write,
};
const struct file_operations ocfs2_dops = {
.llseek = generic_file_llseek,
.read = generic_read_dir,
.readdir = ocfs2_readdir,
.fsync = ocfs2_sync_file,
.release = ocfs2_dir_release,
.open = ocfs2_dir_open,
.unlocked_ioctl = ocfs2_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = ocfs2_compat_ioctl,
#endif
.lock = ocfs2_lock,
.flock = ocfs2_flock,
};
/*
* POSIX-lockless variants of our file_operations.
*
* These will be used if the underlying cluster stack does not support
* posix file locking, if the user passes the "localflocks" mount
* option, or if we have a local-only fs.
*
* ocfs2_flock is in here because all stacks handle UNIX file locks,
* so we still want it in the case of no stack support for
* plocks. Internally, it will do the right thing when asked to ignore
* the cluster.
*/
const struct file_operations ocfs2_fops_no_plocks = {
.llseek = generic_file_llseek,
.read = do_sync_read,
.write = do_sync_write,
.mmap = ocfs2_mmap,
.fsync = ocfs2_sync_file,
.release = ocfs2_file_release,
.open = ocfs2_file_open,
.aio_read = ocfs2_file_aio_read,
.aio_write = ocfs2_file_aio_write,
.unlocked_ioctl = ocfs2_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = ocfs2_compat_ioctl,
#endif
.flock = ocfs2_flock,
.splice_read = ocfs2_file_splice_read,
.splice_write = ocfs2_file_splice_write,
};
const struct file_operations ocfs2_dops = {
const struct file_operations ocfs2_dops_no_plocks = {
.llseek = generic_file_llseek,
.read = generic_read_dir,
.readdir = ocfs2_readdir,