mirror of
https://github.com/Fishwaldo/Star64_linux.git
synced 2025-06-28 09:31:14 +00:00
nfs: per-name sillyunlink exclusion
use d_alloc_parallel() for sillyunlink/lookup exclusion and explicit rwsem (nfs_rmdir() being a writer and nfs_call_unlink() - a reader) for rmdir/sillyunlink one. That ought to make lookup/readdir/!O_CREAT atomic_open really parallel on NFS. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro
parent
9ac3d3e846
commit
884be17535
7 changed files with 71 additions and 174 deletions
213
fs/nfs/unlink.c
213
fs/nfs/unlink.c
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@ -30,45 +30,11 @@
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static void
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nfs_free_unlinkdata(struct nfs_unlinkdata *data)
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{
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iput(data->dir);
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put_rpccred(data->cred);
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kfree(data->args.name.name);
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kfree(data);
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}
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#define NAME_ALLOC_LEN(len) ((len+16) & ~15)
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/**
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* nfs_copy_dname - copy dentry name to data structure
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* @dentry: pointer to dentry
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* @data: nfs_unlinkdata
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*/
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static int nfs_copy_dname(struct dentry *dentry, struct nfs_unlinkdata *data)
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{
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char *str;
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int len = dentry->d_name.len;
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str = kmemdup(dentry->d_name.name, NAME_ALLOC_LEN(len), GFP_KERNEL);
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if (!str)
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return -ENOMEM;
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data->args.name.len = len;
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data->args.name.name = str;
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return 0;
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}
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static void nfs_free_dname(struct nfs_unlinkdata *data)
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{
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kfree(data->args.name.name);
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data->args.name.name = NULL;
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data->args.name.len = 0;
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}
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static void nfs_dec_sillycount(struct inode *dir)
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{
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struct nfs_inode *nfsi = NFS_I(dir);
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if (atomic_dec_return(&nfsi->silly_count) == 1)
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wake_up(&nfsi->waitqueue);
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}
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/**
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* nfs_async_unlink_done - Sillydelete post-processing
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* @task: rpc_task of the sillydelete
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@ -78,7 +44,7 @@ static void nfs_dec_sillycount(struct inode *dir)
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static void nfs_async_unlink_done(struct rpc_task *task, void *calldata)
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{
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struct nfs_unlinkdata *data = calldata;
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struct inode *dir = data->dir;
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struct inode *dir = d_inode(data->dentry->d_parent);
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trace_nfs_sillyrename_unlink(data, task->tk_status);
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if (!NFS_PROTO(dir)->unlink_done(task, dir))
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@ -95,17 +61,21 @@ static void nfs_async_unlink_done(struct rpc_task *task, void *calldata)
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static void nfs_async_unlink_release(void *calldata)
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{
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struct nfs_unlinkdata *data = calldata;
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struct super_block *sb = data->dir->i_sb;
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struct dentry *dentry = data->dentry;
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struct super_block *sb = dentry->d_sb;
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nfs_dec_sillycount(data->dir);
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up_read_non_owner(&NFS_I(d_inode(dentry->d_parent))->rmdir_sem);
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d_lookup_done(dentry);
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nfs_free_unlinkdata(data);
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dput(dentry);
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nfs_sb_deactive(sb);
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}
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static void nfs_unlink_prepare(struct rpc_task *task, void *calldata)
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{
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struct nfs_unlinkdata *data = calldata;
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NFS_PROTO(data->dir)->unlink_rpc_prepare(task, data);
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struct inode *dir = d_inode(data->dentry->d_parent);
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NFS_PROTO(dir)->unlink_rpc_prepare(task, data);
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}
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static const struct rpc_call_ops nfs_unlink_ops = {
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@ -114,7 +84,7 @@ static const struct rpc_call_ops nfs_unlink_ops = {
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.rpc_call_prepare = nfs_unlink_prepare,
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};
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static int nfs_do_call_unlink(struct dentry *parent, struct inode *dir, struct nfs_unlinkdata *data)
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static void nfs_do_call_unlink(struct nfs_unlinkdata *data)
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{
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struct rpc_message msg = {
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.rpc_argp = &data->args,
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@ -129,44 +99,7 @@ static int nfs_do_call_unlink(struct dentry *parent, struct inode *dir, struct n
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.flags = RPC_TASK_ASYNC,
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};
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struct rpc_task *task;
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struct dentry *alias;
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alias = d_lookup(parent, &data->args.name);
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if (alias != NULL) {
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int ret;
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void *devname_garbage = NULL;
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/*
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* Hey, we raced with lookup... See if we need to transfer
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* the sillyrename information to the aliased dentry.
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*/
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nfs_free_dname(data);
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ret = nfs_copy_dname(alias, data);
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spin_lock(&alias->d_lock);
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if (ret == 0 && d_really_is_positive(alias) &&
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!(alias->d_flags & DCACHE_NFSFS_RENAMED)) {
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devname_garbage = alias->d_fsdata;
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alias->d_fsdata = data;
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alias->d_flags |= DCACHE_NFSFS_RENAMED;
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ret = 1;
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} else
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ret = 0;
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spin_unlock(&alias->d_lock);
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nfs_dec_sillycount(dir);
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dput(alias);
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/*
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* If we'd displaced old cached devname, free it. At that
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* point dentry is definitely not a root, so we won't need
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* that anymore.
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*/
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kfree(devname_garbage);
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return ret;
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}
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data->dir = igrab(dir);
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if (!data->dir) {
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nfs_dec_sillycount(dir);
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return 0;
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}
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struct inode *dir = d_inode(data->dentry->d_parent);
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nfs_sb_active(dir->i_sb);
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data->args.fh = NFS_FH(dir);
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nfs_fattr_init(data->res.dir_attr);
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@ -177,71 +110,50 @@ static int nfs_do_call_unlink(struct dentry *parent, struct inode *dir, struct n
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task = rpc_run_task(&task_setup_data);
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if (!IS_ERR(task))
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rpc_put_task_async(task);
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return 1;
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}
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static int nfs_call_unlink(struct dentry *dentry, struct nfs_unlinkdata *data)
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{
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struct dentry *parent;
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struct inode *dir;
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int ret = 0;
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struct inode *dir = d_inode(dentry->d_parent);
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struct dentry *alias;
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parent = dget_parent(dentry);
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if (parent == NULL)
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goto out_free;
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dir = d_inode(parent);
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/* Non-exclusive lock protects against concurrent lookup() calls */
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spin_lock(&dir->i_lock);
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if (atomic_inc_not_zero(&NFS_I(dir)->silly_count) == 0) {
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/* Deferred delete */
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hlist_add_head(&data->list, &NFS_I(dir)->silly_list);
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spin_unlock(&dir->i_lock);
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ret = 1;
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goto out_dput;
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down_read_non_owner(&NFS_I(dir)->rmdir_sem);
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alias = d_alloc_parallel(dentry->d_parent, &data->args.name, &data->wq);
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if (IS_ERR(alias)) {
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up_read_non_owner(&NFS_I(dir)->rmdir_sem);
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return 0;
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}
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spin_unlock(&dir->i_lock);
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ret = nfs_do_call_unlink(parent, dir, data);
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out_dput:
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dput(parent);
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out_free:
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return ret;
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}
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if (!d_in_lookup(alias)) {
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int ret;
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void *devname_garbage = NULL;
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void nfs_wait_on_sillyrename(struct dentry *dentry)
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{
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struct nfs_inode *nfsi = NFS_I(d_inode(dentry));
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wait_event(nfsi->waitqueue, atomic_read(&nfsi->silly_count) <= 1);
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}
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void nfs_block_sillyrename(struct dentry *dentry)
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{
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struct nfs_inode *nfsi = NFS_I(d_inode(dentry));
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wait_event(nfsi->waitqueue, atomic_cmpxchg(&nfsi->silly_count, 1, 0) == 1);
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}
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void nfs_unblock_sillyrename(struct dentry *dentry)
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{
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struct inode *dir = d_inode(dentry);
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struct nfs_inode *nfsi = NFS_I(dir);
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struct nfs_unlinkdata *data;
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atomic_inc(&nfsi->silly_count);
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wake_up(&nfsi->waitqueue);
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spin_lock(&dir->i_lock);
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while (!hlist_empty(&nfsi->silly_list)) {
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if (!atomic_inc_not_zero(&nfsi->silly_count))
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break;
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data = hlist_entry(nfsi->silly_list.first, struct nfs_unlinkdata, list);
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hlist_del(&data->list);
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spin_unlock(&dir->i_lock);
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if (nfs_do_call_unlink(dentry, dir, data) == 0)
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nfs_free_unlinkdata(data);
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spin_lock(&dir->i_lock);
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/*
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* Hey, we raced with lookup... See if we need to transfer
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* the sillyrename information to the aliased dentry.
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*/
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spin_lock(&alias->d_lock);
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if (d_really_is_positive(alias) &&
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!(alias->d_flags & DCACHE_NFSFS_RENAMED)) {
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devname_garbage = alias->d_fsdata;
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alias->d_fsdata = data;
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alias->d_flags |= DCACHE_NFSFS_RENAMED;
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ret = 1;
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} else
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ret = 0;
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spin_unlock(&alias->d_lock);
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dput(alias);
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up_read_non_owner(&NFS_I(dir)->rmdir_sem);
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/*
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* If we'd displaced old cached devname, free it. At that
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* point dentry is definitely not a root, so we won't need
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* that anymore.
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*/
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kfree(devname_garbage);
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return ret;
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}
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spin_unlock(&dir->i_lock);
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data->dentry = alias;
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nfs_do_call_unlink(data);
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return 1;
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}
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/**
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@ -250,7 +162,7 @@ void nfs_unblock_sillyrename(struct dentry *dentry)
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* @dentry: dentry to unlink
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*/
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static int
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nfs_async_unlink(struct inode *dir, struct dentry *dentry)
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nfs_async_unlink(struct dentry *dentry, struct qstr *name)
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{
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struct nfs_unlinkdata *data;
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int status = -ENOMEM;
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@ -259,13 +171,18 @@ nfs_async_unlink(struct inode *dir, struct dentry *dentry)
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data = kzalloc(sizeof(*data), GFP_KERNEL);
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if (data == NULL)
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goto out;
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data->args.name.name = kstrdup(name->name, GFP_KERNEL);
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if (!data->args.name.name)
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goto out_free;
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data->args.name.len = name->len;
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data->cred = rpc_lookup_cred();
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if (IS_ERR(data->cred)) {
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status = PTR_ERR(data->cred);
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goto out_free;
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goto out_free_name;
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}
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data->res.dir_attr = &data->dir_attr;
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init_waitqueue_head(&data->wq);
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status = -EBUSY;
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spin_lock(&dentry->d_lock);
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@ -285,6 +202,8 @@ nfs_async_unlink(struct inode *dir, struct dentry *dentry)
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out_unlock:
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spin_unlock(&dentry->d_lock);
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put_rpccred(data->cred);
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out_free_name:
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kfree(data->args.name.name);
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out_free:
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kfree(data);
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out:
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@ -303,17 +222,15 @@ out:
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void
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nfs_complete_unlink(struct dentry *dentry, struct inode *inode)
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{
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struct nfs_unlinkdata *data = NULL;
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struct nfs_unlinkdata *data;
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spin_lock(&dentry->d_lock);
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if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
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dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
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data = dentry->d_fsdata;
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dentry->d_fsdata = NULL;
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}
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dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
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data = dentry->d_fsdata;
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dentry->d_fsdata = NULL;
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spin_unlock(&dentry->d_lock);
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if (data != NULL && (NFS_STALE(inode) || !nfs_call_unlink(dentry, data)))
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if (NFS_STALE(inode) || !nfs_call_unlink(dentry, data))
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nfs_free_unlinkdata(data);
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}
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@ -560,18 +477,10 @@ nfs_sillyrename(struct inode *dir, struct dentry *dentry)
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/* queue unlink first. Can't do this from rpc_release as it
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* has to allocate memory
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*/
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error = nfs_async_unlink(dir, dentry);
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error = nfs_async_unlink(dentry, &sdentry->d_name);
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if (error)
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goto out_dput;
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/* populate unlinkdata with the right dname */
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error = nfs_copy_dname(sdentry,
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(struct nfs_unlinkdata *)dentry->d_fsdata);
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if (error) {
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nfs_cancel_async_unlink(dentry);
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goto out_dput;
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}
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/* run the rename task, undo unlink if it fails */
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task = nfs_async_rename(dir, dir, dentry, sdentry,
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nfs_complete_sillyrename);
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