/* * 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 "internal.h" struct nfs_unlinkdata { struct hlist_node list; struct nfs_removeargs args; struct nfs_removeres res; struct inode *dir; struct rpc_cred *cred; }; /** * 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; if (!NFS_PROTO(dir)->unlink_done(task, dir)) rpc_restart_call(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; nfs_dec_sillycount(data->dir); nfs_sb_deactive(NFS_SERVER(data->dir)); nfs_free_unlinkdata(data); } static const struct rpc_call_ops nfs_unlink_ops = { .rpc_call_done = nfs_async_unlink_done, .rpc_release = nfs_async_unlink_release, }; 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, .flags = RPC_TASK_ASYNC, }; struct rpc_task *task; struct dentry *alias; alias = d_lookup(parent, &data->args.name); if (alias != NULL) { int ret = 0; /* * Hey, we raced with lookup... See if we need to transfer * the sillyrename information to the aliased dentry. */ nfs_free_dname(data); spin_lock(&alias->d_lock); if (alias->d_inode != NULL && !(alias->d_flags & DCACHE_NFSFS_RENAMED)) { alias->d_fsdata = data; alias->d_flags |= DCACHE_NFSFS_RENAMED; ret = 1; } spin_unlock(&alias->d_lock); nfs_dec_sillycount(dir); dput(alias); return ret; } data->dir = igrab(dir); if (!data->dir) { nfs_dec_sillycount(dir); return 0; } nfs_sb_active(NFS_SERVER(dir)); 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(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 = parent->d_inode; if (nfs_copy_dname(dentry, data) != 0) goto out_dput; /* 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_block_sillyrename(struct dentry *dentry) { struct nfs_inode *nfsi = NFS_I(dentry->d_inode); wait_event(nfsi->waitqueue, atomic_cmpxchg(&nfsi->silly_count, 1, 0) == 1); } void nfs_unblock_sillyrename(struct dentry *dentry) { struct inode *dir = dentry->d_inode; 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 */ int nfs_async_unlink(struct inode *dir, struct dentry *dentry) { struct nfs_unlinkdata *data; int status = -ENOMEM; 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; } status = -EBUSY; spin_lock(&dentry->d_lock); if (dentry->d_flags & DCACHE_NFSFS_RENAMED) goto out_unlock; dentry->d_flags |= DCACHE_NFSFS_RENAMED; dentry->d_fsdata = data; spin_unlock(&dentry->d_lock); 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; } spin_unlock(&dentry->d_lock); if (data != NULL && (NFS_STALE(inode) || !nfs_call_unlink(dentry, data))) nfs_free_unlinkdata(data); }