--- /dev/null
+/*
+ * linux/fs/nfs/unlink.c
+ *
+ * nfs sillydelete handling
+ *
+ */
+
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/dcache.h>
+#include <linux/sunrpc/sched.h>
+#include <linux/sunrpc/clnt.h>
+#include <linux/nfs_fs.h>
+#include <linux/sched.h>
+#include <linux/wait.h>
+#include <linux/namei.h>
+#include <linux/fsnotify.h>
+
+#include "internal.h"
+#include "nfs4_fs.h"
+#include "iostat.h"
+#include "delegation.h"
+
+#include "nfstrace.h"
+
+/**
+ * nfs_free_unlinkdata - release data from a sillydelete operation.
+ * @data: pointer to unlink structure.
+ */
+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
+ *
+ * Do the directory attribute update.
+ */
+static void nfs_async_unlink_done(struct rpc_task *task, void *calldata)
+{
+ struct nfs_unlinkdata *data = calldata;
+ struct inode *dir = data->dir;
+
+ trace_nfs_sillyrename_unlink(data, task->tk_status);
+ if (!NFS_PROTO(dir)->unlink_done(task, dir))
+ rpc_restart_call_prepare(task);
+}
+
+/**
+ * nfs_async_unlink_release - Release the sillydelete data.
+ * @task: rpc_task of the sillydelete
+ *
+ * We need to call nfs_put_unlinkdata as a 'tk_release' task since the
+ * rpc_task would be freed too.
+ */
+static void nfs_async_unlink_release(void *calldata)
+{
+ struct nfs_unlinkdata *data = calldata;
+ struct super_block *sb = data->dir->i_sb;
+
+ nfs_dec_sillycount(data->dir);
+ nfs_free_unlinkdata(data);
+ 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);
+}
+
+static const struct rpc_call_ops nfs_unlink_ops = {
+ .rpc_call_done = nfs_async_unlink_done,
+ .rpc_release = nfs_async_unlink_release,
+ .rpc_call_prepare = nfs_unlink_prepare,
+};
+
+static int nfs_do_call_unlink(struct dentry *parent, struct inode *dir, struct nfs_unlinkdata *data)
+{
+ struct rpc_message msg = {
+ .rpc_argp = &data->args,
+ .rpc_resp = &data->res,
+ .rpc_cred = data->cred,
+ };
+ struct rpc_task_setup task_setup_data = {
+ .rpc_message = &msg,
+ .callback_ops = &nfs_unlink_ops,
+ .callback_data = data,
+ .workqueue = nfsiod_workqueue,
+ .flags = RPC_TASK_ASYNC,
+ };
+ struct rpc_task *task;
+ struct dentry *alias;
+
+ alias = d_lookup(parent, &data->args.name);
+ if (alias != NULL) {
+ int ret;
+ void *devname_garbage = NULL;
+
+ /*
+ * 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) &&
+ !(alias->d_flags & DCACHE_NFSFS_RENAMED)) {
+ devname_garbage = alias->d_fsdata;
+ alias->d_fsdata = data;
+ alias->d_flags |= DCACHE_NFSFS_RENAMED;
+ ret = 1;
+ } else
+ ret = 0;
+ spin_unlock(&alias->d_lock);
+ nfs_dec_sillycount(dir);
+ dput(alias);
+ /*
+ * If we'd displaced old cached devname, free it. At that
+ * point dentry is definitely not a root, so we won't need
+ * that anymore.
+ */
+ 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);
+ 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);
+ 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)
+{
+ struct nfs_unlinkdata *data;
+ int status = -ENOMEM;
+ void *devname_garbage = NULL;
+
+ data = kzalloc(sizeof(*data), GFP_KERNEL);
+ if (data == NULL)
+ goto out;
+
+ data->cred = rpc_lookup_cred();
+ if (IS_ERR(data->cred)) {
+ status = PTR_ERR(data->cred);
+ goto out_free;
+ }
+ data->res.dir_attr = &data->dir_attr;
+
+ status = -EBUSY;
+ spin_lock(&dentry->d_lock);
+ if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
+ goto out_unlock;
+ dentry->d_flags |= DCACHE_NFSFS_RENAMED;
+ devname_garbage = dentry->d_fsdata;
+ dentry->d_fsdata = data;
+ spin_unlock(&dentry->d_lock);
+ /*
+ * If we'd displaced old cached devname, free it. At that
+ * point dentry is definitely not a root, so we won't need
+ * that anymore.
+ */
+ kfree(devname_garbage);
+ return 0;
+out_unlock:
+ spin_unlock(&dentry->d_lock);
+ put_rpccred(data->cred);
+out_free:
+ kfree(data);
+out:
+ return status;
+}
+
+/**
+ * nfs_complete_unlink - Initialize completion of the sillydelete
+ * @dentry: dentry to delete
+ * @inode: inode
+ *
+ * Since we're most likely to be called by dentry_iput(), we
+ * only use the dentry to find the sillydelete. We then copy the name
+ * into the qstr.
+ */
+void
+nfs_complete_unlink(struct dentry *dentry, struct inode *inode)
+{
+ struct nfs_unlinkdata *data = NULL;
+
+ 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;
+ }
+ spin_unlock(&dentry->d_lock);
+
+ if (data != NULL && (NFS_STALE(inode) || !nfs_call_unlink(dentry, data)))
+ nfs_free_unlinkdata(data);
+}
+
+/* Cancel a queued async unlink. Called when a sillyrename run fails. */
+static void
+nfs_cancel_async_unlink(struct dentry *dentry)
+{
+ spin_lock(&dentry->d_lock);
+ if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
+ struct nfs_unlinkdata *data = dentry->d_fsdata;
+
+ dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
+ dentry->d_fsdata = NULL;
+ spin_unlock(&dentry->d_lock);
+ nfs_free_unlinkdata(data);
+ return;
+ }
+ spin_unlock(&dentry->d_lock);
+}
+
+/**
+ * nfs_async_rename_done - Sillyrename post-processing
+ * @task: rpc_task of the sillyrename
+ * @calldata: nfs_renamedata for the sillyrename
+ *
+ * Do the directory attribute updates and the d_move
+ */
+static void nfs_async_rename_done(struct rpc_task *task, void *calldata)
+{
+ struct nfs_renamedata *data = calldata;
+ struct inode *old_dir = data->old_dir;
+ struct inode *new_dir = data->new_dir;
+ struct dentry *old_dentry = data->old_dentry;
+
+ trace_nfs_sillyrename_rename(old_dir, old_dentry,
+ new_dir, data->new_dentry, task->tk_status);
+ if (!NFS_PROTO(old_dir)->rename_done(task, old_dir, new_dir)) {
+ rpc_restart_call_prepare(task);
+ return;
+ }
+
+ if (data->complete)
+ data->complete(task, data);
+}
+
+/**
+ * nfs_async_rename_release - Release the sillyrename data.
+ * @calldata: the struct nfs_renamedata to be released
+ */
+static void nfs_async_rename_release(void *calldata)
+{
+ struct nfs_renamedata *data = calldata;
+ struct super_block *sb = data->old_dir->i_sb;
+
+ if (d_really_is_positive(data->old_dentry))
+ nfs_mark_for_revalidate(d_inode(data->old_dentry));
+
+ dput(data->old_dentry);
+ dput(data->new_dentry);
+ iput(data->old_dir);
+ iput(data->new_dir);
+ nfs_sb_deactive(sb);
+ put_rpccred(data->cred);
+ kfree(data);
+}
+
+static void nfs_rename_prepare(struct rpc_task *task, void *calldata)
+{
+ struct nfs_renamedata *data = calldata;
+ NFS_PROTO(data->old_dir)->rename_rpc_prepare(task, data);
+}
+
+static const struct rpc_call_ops nfs_rename_ops = {
+ .rpc_call_done = nfs_async_rename_done,
+ .rpc_release = nfs_async_rename_release,
+ .rpc_call_prepare = nfs_rename_prepare,
+};
+
+/**
+ * nfs_async_rename - perform an asynchronous rename operation
+ * @old_dir: directory that currently holds the dentry to be renamed
+ * @new_dir: target directory for the rename
+ * @old_dentry: original dentry to be renamed
+ * @new_dentry: dentry to which the old_dentry should be renamed
+ *
+ * It's expected that valid references to the dentries and inodes are held
+ */
+struct rpc_task *
+nfs_async_rename(struct inode *old_dir, struct inode *new_dir,
+ struct dentry *old_dentry, struct dentry *new_dentry,
+ void (*complete)(struct rpc_task *, struct nfs_renamedata *))
+{
+ struct nfs_renamedata *data;
+ struct rpc_message msg = { };
+ struct rpc_task_setup task_setup_data = {
+ .rpc_message = &msg,
+ .callback_ops = &nfs_rename_ops,
+ .workqueue = nfsiod_workqueue,
+ .rpc_client = NFS_CLIENT(old_dir),
+ .flags = RPC_TASK_ASYNC,
+ };
+
+ data = kzalloc(sizeof(*data), GFP_KERNEL);
+ if (data == NULL)
+ return ERR_PTR(-ENOMEM);
+ task_setup_data.callback_data = data;
+
+ data->cred = rpc_lookup_cred();
+ if (IS_ERR(data->cred)) {
+ struct rpc_task *task = ERR_CAST(data->cred);
+ kfree(data);
+ return task;
+ }
+
+ msg.rpc_argp = &data->args;
+ msg.rpc_resp = &data->res;
+ msg.rpc_cred = data->cred;
+
+ /* set up nfs_renamedata */
+ data->old_dir = old_dir;
+ ihold(old_dir);
+ data->new_dir = new_dir;
+ ihold(new_dir);
+ data->old_dentry = dget(old_dentry);
+ data->new_dentry = dget(new_dentry);
+ nfs_fattr_init(&data->old_fattr);
+ nfs_fattr_init(&data->new_fattr);
+ data->complete = complete;
+
+ /* set up nfs_renameargs */
+ data->args.old_dir = NFS_FH(old_dir);
+ data->args.old_name = &old_dentry->d_name;
+ data->args.new_dir = NFS_FH(new_dir);
+ data->args.new_name = &new_dentry->d_name;
+
+ /* set up nfs_renameres */
+ data->res.old_fattr = &data->old_fattr;
+ data->res.new_fattr = &data->new_fattr;
+
+ nfs_sb_active(old_dir->i_sb);
+
+ NFS_PROTO(data->old_dir)->rename_setup(&msg, old_dir);
+
+ return rpc_run_task(&task_setup_data);
+}
+
+/*
+ * Perform tasks needed when a sillyrename is done such as cancelling the
+ * queued async unlink if it failed.
+ */
+static void
+nfs_complete_sillyrename(struct rpc_task *task, struct nfs_renamedata *data)
+{
+ struct dentry *dentry = data->old_dentry;
+
+ if (task->tk_status != 0) {
+ nfs_cancel_async_unlink(dentry);
+ return;
+ }
+
+ /*
+ * vfs_unlink and the like do not issue this when a file is
+ * sillyrenamed, so do it here.
+ */
+ fsnotify_nameremove(dentry, 0);
+}
+
+#define SILLYNAME_PREFIX ".nfs"
+#define SILLYNAME_PREFIX_LEN ((unsigned)sizeof(SILLYNAME_PREFIX) - 1)
+#define SILLYNAME_FILEID_LEN ((unsigned)sizeof(u64) << 1)
+#define SILLYNAME_COUNTER_LEN ((unsigned)sizeof(unsigned int) << 1)
+#define SILLYNAME_LEN (SILLYNAME_PREFIX_LEN + \
+ SILLYNAME_FILEID_LEN + \
+ SILLYNAME_COUNTER_LEN)
+
+/**
+ * nfs_sillyrename - Perform a silly-rename of a dentry
+ * @dir: inode of directory that contains dentry
+ * @dentry: dentry to be sillyrenamed
+ *
+ * NFSv2/3 is stateless and the server doesn't know when the client is
+ * holding a file open. To prevent application problems when a file is
+ * unlinked while it's still open, the client performs a "silly-rename".
+ * That is, it renames the file to a hidden file in the same directory,
+ * and only performs the unlink once the last reference to it is put.
+ *
+ * The final cleanup is done during dentry_iput.
+ *
+ * (Note: NFSv4 is stateful, and has opens, so in theory an NFSv4 server
+ * could take responsibility for keeping open files referenced. The server
+ * would also need to ensure that opened-but-deleted files were kept over
+ * reboots. However, we may not assume a server does so. (RFC 5661
+ * does provide an OPEN4_RESULT_PRESERVE_UNLINKED flag that a server can
+ * use to advertise that it does this; some day we may take advantage of
+ * it.))
+ */
+int
+nfs_sillyrename(struct inode *dir, struct dentry *dentry)
+{
+ static unsigned int sillycounter;
+ unsigned char silly[SILLYNAME_LEN + 1];
+ unsigned long long fileid;
+ struct dentry *sdentry;
+ struct rpc_task *task;
+ int error = -EBUSY;
+
+ dfprintk(VFS, "NFS: silly-rename(%pd2, ct=%d)\n",
+ dentry, d_count(dentry));
+ nfs_inc_stats(dir, NFSIOS_SILLYRENAME);
+
+ /*
+ * We don't allow a dentry to be silly-renamed twice.
+ */
+ if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
+ goto out;
+
+ fileid = NFS_FILEID(d_inode(dentry));
+
+ /* Return delegation in anticipation of the rename */
+ NFS_PROTO(d_inode(dentry))->return_delegation(d_inode(dentry));
+
+ sdentry = NULL;
+ do {
+ int slen;
+ dput(sdentry);
+ sillycounter++;
+ slen = scnprintf(silly, sizeof(silly),
+ SILLYNAME_PREFIX "%0*llx%0*x",
+ SILLYNAME_FILEID_LEN, fileid,
+ SILLYNAME_COUNTER_LEN, sillycounter);
+
+ dfprintk(VFS, "NFS: trying to rename %pd to %s\n",
+ dentry, silly);
+
+ sdentry = lookup_one_len(silly, dentry->d_parent, slen);
+ /*
+ * N.B. Better to return EBUSY here ... it could be
+ * dangerous to delete the file while it's in use.
+ */
+ if (IS_ERR(sdentry))
+ goto out;
+ } while (d_inode(sdentry) != NULL); /* need negative lookup */
+
+ /* queue unlink first. Can't do this from rpc_release as it
+ * has to allocate memory
+ */
+ error = nfs_async_unlink(dir, dentry);
+ 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);
+ if (IS_ERR(task)) {
+ error = -EBUSY;
+ nfs_cancel_async_unlink(dentry);
+ goto out_dput;
+ }
+
+ /* wait for the RPC task to complete, unless a SIGKILL intervenes */
+ error = rpc_wait_for_completion_task(task);
+ if (error == 0)
+ error = task->tk_status;
+ switch (error) {
+ case 0:
+ /* The rename succeeded */
+ nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
+ d_move(dentry, sdentry);
+ break;
+ case -ERESTARTSYS:
+ /* The result of the rename is unknown. Play it safe by
+ * forcing a new lookup */
+ d_drop(dentry);
+ d_drop(sdentry);
+ }
+ rpc_put_task(task);
+out_dput:
+ dput(sdentry);
+out:
+ return error;
+}
Code Review / kvmfornfv.git / blobdiff