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authorAl Viro <viro@zeniv.linux.org.uk>2016-04-28 23:56:31 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2016-05-09 11:39:45 -0400
commit884be175351e73c515303118150f195dd611787c (patch)
treeba85a80a6422df631b18af344132c6fcb67f1594 /fs/nfs/unlink.c
parent9ac3d3e8460e3fa6f3a9a39c2049904005016db6 (diff)
downloadop-kernel-dev-884be175351e73c515303118150f195dd611787c.zip
op-kernel-dev-884be175351e73c515303118150f195dd611787c.tar.gz
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>
Diffstat (limited to 'fs/nfs/unlink.c')
-rw-r--r--fs/nfs/unlink.c193
1 files changed, 51 insertions, 142 deletions
diff --git a/fs/nfs/unlink.c b/fs/nfs/unlink.c
index 7d6deac..1868246 100644
--- a/fs/nfs/unlink.c
+++ b/fs/nfs/unlink.c
@@ -30,45 +30,11 @@
static void
nfs_free_unlinkdata(struct nfs_unlinkdata *data)
{
- iput(data->dir);
put_rpccred(data->cred);
kfree(data->args.name.name);
kfree(data);
}
-#define NAME_ALLOC_LEN(len) ((len+16) & ~15)
-/**
- * nfs_copy_dname - copy dentry name to data structure
- * @dentry: pointer to dentry
- * @data: nfs_unlinkdata
- */
-static int nfs_copy_dname(struct dentry *dentry, struct nfs_unlinkdata *data)
-{
- char *str;
- int len = dentry->d_name.len;
-
- str = kmemdup(dentry->d_name.name, NAME_ALLOC_LEN(len), GFP_KERNEL);
- if (!str)
- return -ENOMEM;
- data->args.name.len = len;
- data->args.name.name = str;
- return 0;
-}
-
-static void nfs_free_dname(struct nfs_unlinkdata *data)
-{
- kfree(data->args.name.name);
- data->args.name.name = NULL;
- data->args.name.len = 0;
-}
-
-static void nfs_dec_sillycount(struct inode *dir)
-{
- struct nfs_inode *nfsi = NFS_I(dir);
- if (atomic_dec_return(&nfsi->silly_count) == 1)
- wake_up(&nfsi->waitqueue);
-}
-
/**
* nfs_async_unlink_done - Sillydelete post-processing
* @task: rpc_task of the sillydelete
@@ -78,7 +44,7 @@ static void nfs_dec_sillycount(struct inode *dir)
static void nfs_async_unlink_done(struct rpc_task *task, void *calldata)
{
struct nfs_unlinkdata *data = calldata;
- struct inode *dir = data->dir;
+ struct inode *dir = d_inode(data->dentry->d_parent);
trace_nfs_sillyrename_unlink(data, task->tk_status);
if (!NFS_PROTO(dir)->unlink_done(task, dir))
@@ -95,17 +61,21 @@ static void nfs_async_unlink_done(struct rpc_task *task, void *calldata)
static void nfs_async_unlink_release(void *calldata)
{
struct nfs_unlinkdata *data = calldata;
- struct super_block *sb = data->dir->i_sb;
+ struct dentry *dentry = data->dentry;
+ struct super_block *sb = dentry->d_sb;
- nfs_dec_sillycount(data->dir);
+ up_read_non_owner(&NFS_I(d_inode(dentry->d_parent))->rmdir_sem);
+ d_lookup_done(dentry);
nfs_free_unlinkdata(data);
+ dput(dentry);
nfs_sb_deactive(sb);
}
static void nfs_unlink_prepare(struct rpc_task *task, void *calldata)
{
struct nfs_unlinkdata *data = calldata;
- NFS_PROTO(data->dir)->unlink_rpc_prepare(task, data);
+ struct inode *dir = d_inode(data->dentry->d_parent);
+ NFS_PROTO(dir)->unlink_rpc_prepare(task, data);
}
static const struct rpc_call_ops nfs_unlink_ops = {
@@ -114,7 +84,7 @@ static const struct rpc_call_ops nfs_unlink_ops = {
.rpc_call_prepare = nfs_unlink_prepare,
};
-static int nfs_do_call_unlink(struct dentry *parent, struct inode *dir, struct nfs_unlinkdata *data)
+static void nfs_do_call_unlink(struct nfs_unlinkdata *data)
{
struct rpc_message msg = {
.rpc_argp = &data->args,
@@ -129,10 +99,31 @@ static int nfs_do_call_unlink(struct dentry *parent, struct inode *dir, struct n
.flags = RPC_TASK_ASYNC,
};
struct rpc_task *task;
+ struct inode *dir = d_inode(data->dentry->d_parent);
+ nfs_sb_active(dir->i_sb);
+ data->args.fh = NFS_FH(dir);
+ nfs_fattr_init(data->res.dir_attr);
+
+ NFS_PROTO(dir)->unlink_setup(&msg, dir);
+
+ task_setup_data.rpc_client = NFS_CLIENT(dir);
+ task = rpc_run_task(&task_setup_data);
+ if (!IS_ERR(task))
+ rpc_put_task_async(task);
+}
+
+static int nfs_call_unlink(struct dentry *dentry, struct nfs_unlinkdata *data)
+{
+ struct inode *dir = d_inode(dentry->d_parent);
struct dentry *alias;
- alias = d_lookup(parent, &data->args.name);
- if (alias != NULL) {
+ down_read_non_owner(&NFS_I(dir)->rmdir_sem);
+ alias = d_alloc_parallel(dentry->d_parent, &data->args.name, &data->wq);
+ if (IS_ERR(alias)) {
+ up_read_non_owner(&NFS_I(dir)->rmdir_sem);
+ return 0;
+ }
+ if (!d_in_lookup(alias)) {
int ret;
void *devname_garbage = NULL;
@@ -140,10 +131,8 @@ static int nfs_do_call_unlink(struct dentry *parent, struct inode *dir, struct n
* Hey, we raced with lookup... See if we need to transfer
* the sillyrename information to the aliased dentry.
*/
- nfs_free_dname(data);
- ret = nfs_copy_dname(alias, data);
spin_lock(&alias->d_lock);
- if (ret == 0 && d_really_is_positive(alias) &&
+ if (d_really_is_positive(alias) &&
!(alias->d_flags & DCACHE_NFSFS_RENAMED)) {
devname_garbage = alias->d_fsdata;
alias->d_fsdata = data;
@@ -152,8 +141,8 @@ static int nfs_do_call_unlink(struct dentry *parent, struct inode *dir, struct n
} else
ret = 0;
spin_unlock(&alias->d_lock);
- nfs_dec_sillycount(dir);
dput(alias);
+ up_read_non_owner(&NFS_I(dir)->rmdir_sem);
/*
* If we'd displaced old cached devname, free it. At that
* point dentry is definitely not a root, so we won't need
@@ -162,95 +151,18 @@ static int nfs_do_call_unlink(struct dentry *parent, struct inode *dir, struct n
kfree(devname_garbage);
return ret;
}
- data->dir = igrab(dir);
- if (!data->dir) {
- nfs_dec_sillycount(dir);
- return 0;
- }
- nfs_sb_active(dir->i_sb);
- data->args.fh = NFS_FH(dir);
- nfs_fattr_init(data->res.dir_attr);
-
- NFS_PROTO(dir)->unlink_setup(&msg, dir);
-
- task_setup_data.rpc_client = NFS_CLIENT(dir);
- task = rpc_run_task(&task_setup_data);
- if (!IS_ERR(task))
- rpc_put_task_async(task);
+ data->dentry = alias;
+ nfs_do_call_unlink(data);
return 1;
}
-static int nfs_call_unlink(struct dentry *dentry, struct nfs_unlinkdata *data)
-{
- struct dentry *parent;
- struct inode *dir;
- int ret = 0;
-
-
- parent = dget_parent(dentry);
- if (parent == NULL)
- goto out_free;
- dir = d_inode(parent);
- /* Non-exclusive lock protects against concurrent lookup() calls */
- spin_lock(&dir->i_lock);
- if (atomic_inc_not_zero(&NFS_I(dir)->silly_count) == 0) {
- /* Deferred delete */
- hlist_add_head(&data->list, &NFS_I(dir)->silly_list);
- spin_unlock(&dir->i_lock);
- ret = 1;
- goto out_dput;
- }
- spin_unlock(&dir->i_lock);
- ret = nfs_do_call_unlink(parent, dir, data);
-out_dput:
- dput(parent);
-out_free:
- return ret;
-}
-
-void nfs_wait_on_sillyrename(struct dentry *dentry)
-{
- struct nfs_inode *nfsi = NFS_I(d_inode(dentry));
-
- wait_event(nfsi->waitqueue, atomic_read(&nfsi->silly_count) <= 1);
-}
-
-void nfs_block_sillyrename(struct dentry *dentry)
-{
- struct nfs_inode *nfsi = NFS_I(d_inode(dentry));
-
- wait_event(nfsi->waitqueue, atomic_cmpxchg(&nfsi->silly_count, 1, 0) == 1);
-}
-
-void nfs_unblock_sillyrename(struct dentry *dentry)
-{
- struct inode *dir = d_inode(dentry);
- struct nfs_inode *nfsi = NFS_I(dir);
- struct nfs_unlinkdata *data;
-
- atomic_inc(&nfsi->silly_count);
- wake_up(&nfsi->waitqueue);
- spin_lock(&dir->i_lock);
- while (!hlist_empty(&nfsi->silly_list)) {
- if (!atomic_inc_not_zero(&nfsi->silly_count))
- break;
- data = hlist_entry(nfsi->silly_list.first, struct nfs_unlinkdata, list);
- hlist_del(&data->list);
- spin_unlock(&dir->i_lock);
- if (nfs_do_call_unlink(dentry, dir, data) == 0)
- nfs_free_unlinkdata(data);
- spin_lock(&dir->i_lock);
- }
- spin_unlock(&dir->i_lock);
-}
-
/**
* nfs_async_unlink - asynchronous unlinking of a file
* @dir: parent directory of dentry
* @dentry: dentry to unlink
*/
static int
-nfs_async_unlink(struct inode *dir, struct dentry *dentry)
+nfs_async_unlink(struct dentry *dentry, struct qstr *name)
{
struct nfs_unlinkdata *data;
int status = -ENOMEM;
@@ -259,13 +171,18 @@ nfs_async_unlink(struct inode *dir, struct dentry *dentry)
data = kzalloc(sizeof(*data), GFP_KERNEL);
if (data == NULL)
goto out;
+ data->args.name.name = kstrdup(name->name, GFP_KERNEL);
+ if (!data->args.name.name)
+ goto out_free;
+ data->args.name.len = name->len;
data->cred = rpc_lookup_cred();
if (IS_ERR(data->cred)) {
status = PTR_ERR(data->cred);
- goto out_free;
+ goto out_free_name;
}
data->res.dir_attr = &data->dir_attr;
+ init_waitqueue_head(&data->wq);
status = -EBUSY;
spin_lock(&dentry->d_lock);
@@ -285,6 +202,8 @@ nfs_async_unlink(struct inode *dir, struct dentry *dentry)
out_unlock:
spin_unlock(&dentry->d_lock);
put_rpccred(data->cred);
+out_free_name:
+ kfree(data->args.name.name);
out_free:
kfree(data);
out:
@@ -303,17 +222,15 @@ out:
void
nfs_complete_unlink(struct dentry *dentry, struct inode *inode)
{
- struct nfs_unlinkdata *data = NULL;
+ struct nfs_unlinkdata *data;
spin_lock(&dentry->d_lock);
- if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
- dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
- data = dentry->d_fsdata;
- dentry->d_fsdata = NULL;
- }
+ dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
+ data = dentry->d_fsdata;
+ dentry->d_fsdata = NULL;
spin_unlock(&dentry->d_lock);
- if (data != NULL && (NFS_STALE(inode) || !nfs_call_unlink(dentry, data)))
+ if (NFS_STALE(inode) || !nfs_call_unlink(dentry, data))
nfs_free_unlinkdata(data);
}
@@ -560,18 +477,10 @@ nfs_sillyrename(struct inode *dir, struct dentry *dentry)
/* queue unlink first. Can't do this from rpc_release as it
* has to allocate memory
*/
- error = nfs_async_unlink(dir, dentry);
+ error = nfs_async_unlink(dentry, &sdentry->d_name);
if (error)
goto out_dput;
- /* populate unlinkdata with the right dname */
- error = nfs_copy_dname(sdentry,
- (struct nfs_unlinkdata *)dentry->d_fsdata);
- if (error) {
- nfs_cancel_async_unlink(dentry);
- goto out_dput;
- }
-
/* run the rename task, undo unlink if it fails */
task = nfs_async_rename(dir, dir, dentry, sdentry,
nfs_complete_sillyrename);
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