diff options
Diffstat (limited to 'fs/nfs/dir.c')
| -rw-r--r-- | fs/nfs/dir.c | 1562 |
1 files changed, 1562 insertions, 0 deletions
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c new file mode 100644 index 000000000000..73f96acd5d37 --- /dev/null +++ b/fs/nfs/dir.c @@ -0,0 +1,1562 @@ +/* + * linux/fs/nfs/dir.c + * + * Copyright (C) 1992 Rick Sladkey + * + * nfs directory handling functions + * + * 10 Apr 1996 Added silly rename for unlink --okir + * 28 Sep 1996 Improved directory cache --okir + * 23 Aug 1997 Claus Heine claus@momo.math.rwth-aachen.de + * Re-implemented silly rename for unlink, newly implemented + * silly rename for nfs_rename() following the suggestions + * of Olaf Kirch (okir) found in this file. + * Following Linus comments on my original hack, this version + * depends only on the dcache stuff and doesn't touch the inode + * layer (iput() and friends). + * 6 Jun 1999 Cache readdir lookups in the page cache. -DaveM + */ + +#include <linux/time.h> +#include <linux/errno.h> +#include <linux/stat.h> +#include <linux/fcntl.h> +#include <linux/string.h> +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/mm.h> +#include <linux/sunrpc/clnt.h> +#include <linux/nfs_fs.h> +#include <linux/nfs_mount.h> +#include <linux/pagemap.h> +#include <linux/smp_lock.h> +#include <linux/namei.h> + +#include "delegation.h" + +#define NFS_PARANOIA 1 +/* #define NFS_DEBUG_VERBOSE 1 */ + +static int nfs_opendir(struct inode *, struct file *); +static int nfs_readdir(struct file *, void *, filldir_t); +static struct dentry *nfs_lookup(struct inode *, struct dentry *, struct nameidata *); +static int nfs_create(struct inode *, struct dentry *, int, struct nameidata *); +static int nfs_mkdir(struct inode *, struct dentry *, int); +static int nfs_rmdir(struct inode *, struct dentry *); +static int nfs_unlink(struct inode *, struct dentry *); +static int nfs_symlink(struct inode *, struct dentry *, const char *); +static int nfs_link(struct dentry *, struct inode *, struct dentry *); +static int nfs_mknod(struct inode *, struct dentry *, int, dev_t); +static int nfs_rename(struct inode *, struct dentry *, + struct inode *, struct dentry *); +static int nfs_fsync_dir(struct file *, struct dentry *, int); + +struct file_operations nfs_dir_operations = { + .read = generic_read_dir, + .readdir = nfs_readdir, + .open = nfs_opendir, + .release = nfs_release, + .fsync = nfs_fsync_dir, +}; + +struct inode_operations nfs_dir_inode_operations = { + .create = nfs_create, + .lookup = nfs_lookup, + .link = nfs_link, + .unlink = nfs_unlink, + .symlink = nfs_symlink, + .mkdir = nfs_mkdir, + .rmdir = nfs_rmdir, + .mknod = nfs_mknod, + .rename = nfs_rename, + .permission = nfs_permission, + .getattr = nfs_getattr, + .setattr = nfs_setattr, +}; + +#ifdef CONFIG_NFS_V4 + +static struct dentry *nfs_atomic_lookup(struct inode *, struct dentry *, struct nameidata *); +struct inode_operations nfs4_dir_inode_operations = { + .create = nfs_create, + .lookup = nfs_atomic_lookup, + .link = nfs_link, + .unlink = nfs_unlink, + .symlink = nfs_symlink, + .mkdir = nfs_mkdir, + .rmdir = nfs_rmdir, + .mknod = nfs_mknod, + .rename = nfs_rename, + .permission = nfs_permission, + .getattr = nfs_getattr, + .setattr = nfs_setattr, +}; + +#endif /* CONFIG_NFS_V4 */ + +/* + * Open file + */ +static int +nfs_opendir(struct inode *inode, struct file *filp) +{ + int res = 0; + + lock_kernel(); + /* Call generic open code in order to cache credentials */ + if (!res) + res = nfs_open(inode, filp); + unlock_kernel(); + return res; +} + +typedef u32 * (*decode_dirent_t)(u32 *, struct nfs_entry *, int); +typedef struct { + struct file *file; + struct page *page; + unsigned long page_index; + u32 *ptr; + u64 target; + struct nfs_entry *entry; + decode_dirent_t decode; + int plus; + int error; +} nfs_readdir_descriptor_t; + +/* Now we cache directories properly, by stuffing the dirent + * data directly in the page cache. + * + * Inode invalidation due to refresh etc. takes care of + * _everything_, no sloppy entry flushing logic, no extraneous + * copying, network direct to page cache, the way it was meant + * to be. + * + * NOTE: Dirent information verification is done always by the + * page-in of the RPC reply, nowhere else, this simplies + * things substantially. + */ +static +int nfs_readdir_filler(nfs_readdir_descriptor_t *desc, struct page *page) +{ + struct file *file = desc->file; + struct inode *inode = file->f_dentry->d_inode; + struct rpc_cred *cred = nfs_file_cred(file); + unsigned long timestamp; + int error; + + dfprintk(VFS, "NFS: nfs_readdir_filler() reading cookie %Lu into page %lu.\n", (long long)desc->entry->cookie, page->index); + + again: + timestamp = jiffies; + error = NFS_PROTO(inode)->readdir(file->f_dentry, cred, desc->entry->cookie, page, + NFS_SERVER(inode)->dtsize, desc->plus); + if (error < 0) { + /* We requested READDIRPLUS, but the server doesn't grok it */ + if (error == -ENOTSUPP && desc->plus) { + NFS_SERVER(inode)->caps &= ~NFS_CAP_READDIRPLUS; + NFS_FLAGS(inode) &= ~NFS_INO_ADVISE_RDPLUS; + desc->plus = 0; + goto again; + } + goto error; + } + SetPageUptodate(page); + NFS_FLAGS(inode) |= NFS_INO_INVALID_ATIME; + /* Ensure consistent page alignment of the data. + * Note: assumes we have exclusive access to this mapping either + * throught inode->i_sem or some other mechanism. + */ + if (page->index == 0) { + invalidate_inode_pages(inode->i_mapping); + NFS_I(inode)->readdir_timestamp = timestamp; + } + unlock_page(page); + return 0; + error: + SetPageError(page); + unlock_page(page); + nfs_zap_caches(inode); + desc->error = error; + return -EIO; +} + +static inline +int dir_decode(nfs_readdir_descriptor_t *desc) +{ + u32 *p = desc->ptr; + p = desc->decode(p, desc->entry, desc->plus); + if (IS_ERR(p)) + return PTR_ERR(p); + desc->ptr = p; + return 0; +} + +static inline +void dir_page_release(nfs_readdir_descriptor_t *desc) +{ + kunmap(desc->page); + page_cache_release(desc->page); + desc->page = NULL; + desc->ptr = NULL; +} + +/* + * Given a pointer to a buffer that has already been filled by a call + * to readdir, find the next entry. + * + * If the end of the buffer has been reached, return -EAGAIN, if not, + * return the offset within the buffer of the next entry to be + * read. + */ +static inline +int find_dirent(nfs_readdir_descriptor_t *desc, struct page *page) +{ + struct nfs_entry *entry = desc->entry; + int loop_count = 0, + status; + + while((status = dir_decode(desc)) == 0) { + dfprintk(VFS, "NFS: found cookie %Lu\n", (long long)entry->cookie); + if (entry->prev_cookie == desc->target) + break; + if (loop_count++ > 200) { + loop_count = 0; + schedule(); + } + } + dfprintk(VFS, "NFS: find_dirent() returns %d\n", status); + return status; +} + +/* + * Find the given page, and call find_dirent() in order to try to + * return the next entry. + */ +static inline +int find_dirent_page(nfs_readdir_descriptor_t *desc) +{ + struct inode *inode = desc->file->f_dentry->d_inode; + struct page *page; + int status; + + dfprintk(VFS, "NFS: find_dirent_page() searching directory page %ld\n", desc->page_index); + + page = read_cache_page(inode->i_mapping, desc->page_index, + (filler_t *)nfs_readdir_filler, desc); + if (IS_ERR(page)) { + status = PTR_ERR(page); + goto out; + } + if (!PageUptodate(page)) + goto read_error; + + /* NOTE: Someone else may have changed the READDIRPLUS flag */ + desc->page = page; + desc->ptr = kmap(page); /* matching kunmap in nfs_do_filldir */ + status = find_dirent(desc, page); + if (status < 0) + dir_page_release(desc); + out: + dfprintk(VFS, "NFS: find_dirent_page() returns %d\n", status); + return status; + read_error: + page_cache_release(page); + return -EIO; +} + +/* + * Recurse through the page cache pages, and return a + * filled nfs_entry structure of the next directory entry if possible. + * + * The target for the search is 'desc->target'. + */ +static inline +int readdir_search_pagecache(nfs_readdir_descriptor_t *desc) +{ + int loop_count = 0; + int res; + + dfprintk(VFS, "NFS: readdir_search_pagecache() searching for cookie %Lu\n", (long long)desc->target); + for (;;) { + res = find_dirent_page(desc); + if (res != -EAGAIN) + break; + /* Align to beginning of next page */ + desc->page_index ++; + if (loop_count++ > 200) { + loop_count = 0; + schedule(); + } + } + dfprintk(VFS, "NFS: readdir_search_pagecache() returned %d\n", res); + return res; +} + +static inline unsigned int dt_type(struct inode *inode) +{ + return (inode->i_mode >> 12) & 15; +} + +static struct dentry *nfs_readdir_lookup(nfs_readdir_descriptor_t *desc); + +/* + * Once we've found the start of the dirent within a page: fill 'er up... + */ +static +int nfs_do_filldir(nfs_readdir_descriptor_t *desc, void *dirent, + filldir_t filldir) +{ + struct file *file = desc->file; + struct nfs_entry *entry = desc->entry; + struct dentry *dentry = NULL; + unsigned long fileid; + int loop_count = 0, + res; + + dfprintk(VFS, "NFS: nfs_do_filldir() filling starting @ cookie %Lu\n", (long long)desc->target); + + for(;;) { + unsigned d_type = DT_UNKNOWN; + /* Note: entry->prev_cookie contains the cookie for + * retrieving the current dirent on the server */ + fileid = nfs_fileid_to_ino_t(entry->ino); + + /* Get a dentry if we have one */ + if (dentry != NULL) + dput(dentry); + dentry = nfs_readdir_lookup(desc); + + /* Use readdirplus info */ + if (dentry != NULL && dentry->d_inode != NULL) { + d_type = dt_type(dentry->d_inode); + fileid = dentry->d_inode->i_ino; + } + + res = filldir(dirent, entry->name, entry->len, + entry->prev_cookie, fileid, d_type); + if (res < 0) + break; + file->f_pos = desc->target = entry->cookie; + if (dir_decode(desc) != 0) { + desc->page_index ++; + break; + } + if (loop_count++ > 200) { + loop_count = 0; + schedule(); + } + } + dir_page_release(desc); + if (dentry != NULL) + dput(dentry); + dfprintk(VFS, "NFS: nfs_do_filldir() filling ended @ cookie %Lu; returning = %d\n", (long long)desc->target, res); + return res; +} + +/* + * If we cannot find a cookie in our cache, we suspect that this is + * because it points to a deleted file, so we ask the server to return + * whatever it thinks is the next entry. We then feed this to filldir. + * If all goes well, we should then be able to find our way round the + * cache on the next call to readdir_search_pagecache(); + * + * NOTE: we cannot add the anonymous page to the pagecache because + * the data it contains might not be page aligned. Besides, + * we should already have a complete representation of the + * directory in the page cache by the time we get here. + */ +static inline +int uncached_readdir(nfs_readdir_descriptor_t *desc, void *dirent, + filldir_t filldir) +{ + struct file *file = desc->file; + struct inode *inode = file->f_dentry->d_inode; + struct rpc_cred *cred = nfs_file_cred(file); + struct page *page = NULL; + int status; + + dfprintk(VFS, "NFS: uncached_readdir() searching for cookie %Lu\n", (long long)desc->target); + + page = alloc_page(GFP_HIGHUSER); + if (!page) { + status = -ENOMEM; + goto out; + } + desc->error = NFS_PROTO(inode)->readdir(file->f_dentry, cred, desc->target, + page, + NFS_SERVER(inode)->dtsize, + desc->plus); + NFS_FLAGS(inode) |= NFS_INO_INVALID_ATIME; + desc->page = page; + desc->ptr = kmap(page); /* matching kunmap in nfs_do_filldir */ + if (desc->error >= 0) { + if ((status = dir_decode(desc)) == 0) + desc->entry->prev_cookie = desc->target; + } else + status = -EIO; + if (status < 0) + goto out_release; + + status = nfs_do_filldir(desc, dirent, filldir); + + /* Reset read descriptor so it searches the page cache from + * the start upon the next call to readdir_search_pagecache() */ + desc->page_index = 0; + desc->entry->cookie = desc->entry->prev_cookie = 0; + desc->entry->eof = 0; + out: + dfprintk(VFS, "NFS: uncached_readdir() returns %d\n", status); + return status; + out_release: + dir_page_release(desc); + goto out; +} + +/* The file offset position is now represented as a true offset into the + * page cache as is the case in most of the other filesystems. + */ +static int nfs_readdir(struct file *filp, void *dirent, filldir_t filldir) +{ + struct dentry *dentry = filp->f_dentry; + struct inode *inode = dentry->d_inode; + nfs_readdir_descriptor_t my_desc, + *desc = &my_desc; + struct nfs_entry my_entry; + struct nfs_fh fh; + struct nfs_fattr fattr; + long res; + + lock_kernel(); + + res = nfs_revalidate_inode(NFS_SERVER(inode), inode); + if (res < 0) { + unlock_kernel(); + return res; + } + + /* + * filp->f_pos points to the file offset in the page cache. + * but if the cache has meanwhile been zapped, we need to + * read from the last dirent to revalidate f_pos + * itself. + */ + memset(desc, 0, sizeof(*desc)); + + desc->file = filp; + desc->target = filp->f_pos; + desc->decode = NFS_PROTO(inode)->decode_dirent; + desc->plus = NFS_USE_READDIRPLUS(inode); + + my_entry.cookie = my_entry.prev_cookie = 0; + my_entry.eof = 0; + my_entry.fh = &fh; + my_entry.fattr = &fattr; + desc->entry = &my_entry; + + while(!desc->entry->eof) { + res = readdir_search_pagecache(desc); + if (res == -EBADCOOKIE) { + /* This means either end of directory */ + if (desc->entry->cookie != desc->target) { + /* Or that the server has 'lost' a cookie */ + res = uncached_readdir(desc, dirent, filldir); + if (res >= 0) + continue; + } + res = 0; + break; + } + if (res == -ETOOSMALL && desc->plus) { + NFS_FLAGS(inode) &= ~NFS_INO_ADVISE_RDPLUS; + nfs_zap_caches(inode); + desc->plus = 0; + desc->entry->eof = 0; + continue; + } + if (res < 0) + break; + + res = nfs_do_filldir(desc, dirent, filldir); + if (res < 0) { + res = 0; + break; + } + } + unlock_kernel(); + if (desc->error < 0) + return desc->error; + if (res < 0) + return res; + return 0; +} + +/* + * All directory operations under NFS are synchronous, so fsync() + * is a dummy operation. + */ +int nfs_fsync_dir(struct file *filp, struct dentry *dentry, int datasync) +{ + return 0; +} + +/* + * A check for whether or not the parent directory has changed. + * In the case it has, we assume that the dentries are untrustworthy + * and may need to be looked up again. + */ +static inline int nfs_check_verifier(struct inode *dir, struct dentry *dentry) +{ + if (IS_ROOT(dentry)) + return 1; + if ((NFS_FLAGS(dir) & NFS_INO_INVALID_ATTR) != 0 + || nfs_attribute_timeout(dir)) + return 0; + return nfs_verify_change_attribute(dir, (unsigned long)dentry->d_fsdata); +} + +static inline void nfs_set_verifier(struct dentry * dentry, unsigned long verf) +{ + dentry->d_fsdata = (void *)verf; +} + +/* + * Whenever an NFS operation succeeds, we know that the dentry + * is valid, so we update the revalidation timestamp. + */ +static inline void nfs_renew_times(struct dentry * dentry) +{ + dentry->d_time = jiffies; +} + +static inline +int nfs_lookup_verify_inode(struct inode *inode, struct nameidata *nd) +{ + struct nfs_server *server = NFS_SERVER(inode); + + if (nd != NULL) { + int ndflags = nd->flags; + /* VFS wants an on-the-wire revalidation */ + if (ndflags & LOOKUP_REVAL) + goto out_force; + /* This is an open(2) */ + if ((ndflags & LOOKUP_OPEN) && + !(ndflags & LOOKUP_CONTINUE) && + !(server->flags & NFS_MOUNT_NOCTO)) + goto out_force; + } + return nfs_revalidate_inode(server, inode); +out_force: + return __nfs_revalidate_inode(server, inode); +} + +/* + * We judge how long we want to trust negative + * dentries by looking at the parent inode mtime. + * + * If parent mtime has changed, we revalidate, else we wait for a + * period corresponding to the parent's attribute cache timeout value. + */ +static inline +int nfs_neg_need_reval(struct inode *dir, struct dentry *dentry, + struct nameidata *nd) +{ + int ndflags = 0; + + if (nd) + ndflags = nd->flags; + /* Don't revalidate a negative dentry if we're creating a new file */ + if ((ndflags & LOOKUP_CREATE) && !(ndflags & LOOKUP_CONTINUE)) + return 0; + return !nfs_check_verifier(dir, dentry); +} + +/* + * This is called every time the dcache has a lookup hit, + * and we should check whether we can really trust that + * lookup. + * + * NOTE! The hit can be a negative hit too, don't assume + * we have an inode! + * + * If the parent directory is seen to have changed, we throw out the + * cached dentry and do a new lookup. + */ +static int nfs_lookup_revalidate(struct dentry * dentry, struct nameidata *nd) +{ + struct inode *dir; + struct inode *inode; + struct dentry *parent; + int error; + struct nfs_fh fhandle; + struct nfs_fattr fattr; + unsigned long verifier; + + parent = dget_parent(dentry); + lock_kernel(); + dir = parent->d_inode; + inode = dentry->d_inode; + + if (!inode) { + if (nfs_neg_need_reval(dir, dentry, nd)) + goto out_bad; + goto out_valid; + } + + if (is_bad_inode(inode)) { + dfprintk(VFS, "nfs_lookup_validate: %s/%s has dud inode\n", + dentry->d_parent->d_name.name, dentry->d_name.name); + goto out_bad; + } + + /* Revalidate parent directory attribute cache */ + if (nfs_revalidate_inode(NFS_SERVER(dir), dir) < 0) + goto out_zap_parent; + + /* Force a full look up iff the parent directory has changed */ + if (nfs_check_verifier(dir, dentry)) { + if (nfs_lookup_verify_inode(inode, nd)) + goto out_zap_parent; + goto out_valid; + } + + if (NFS_STALE(inode)) + goto out_bad; + + verifier = nfs_save_change_attribute(dir); + error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, &fhandle, &fattr); + if (error) + goto out_bad; + if (nfs_compare_fh(NFS_FH(inode), &fhandle)) + goto out_bad; + if ((error = nfs_refresh_inode(inode, &fattr)) != 0) + goto out_bad; + + nfs_renew_times(dentry); + nfs_set_verifier(dentry, verifier); + out_valid: + unlock_kernel(); + dput(parent); + return 1; +out_zap_parent: + nfs_zap_caches(dir); + out_bad: + NFS_CACHEINV(dir); + if (inode && S_ISDIR(inode->i_mode)) { + /* Purge readdir caches. */ + nfs_zap_caches(inode); + /* If we have submounts, don't unhash ! */ + if (have_submounts(dentry)) + goto out_valid; + shrink_dcache_parent(dentry); + } + d_drop(dentry); + unlock_kernel(); + dput(parent); + return 0; +} + +/* + * This is called from dput() when d_count is going to 0. + */ +static int nfs_dentry_delete(struct dentry *dentry) +{ + dfprintk(VFS, "NFS: dentry_delete(%s/%s, %x)\n", + dentry->d_parent->d_name.name, dentry->d_name.name, + dentry->d_flags); + + if (dentry->d_flags & DCACHE_NFSFS_RENAMED) { + /* Unhash it, so that ->d_iput() would be called */ + return 1; + } + if (!(dentry->d_sb->s_flags & MS_ACTIVE)) { + /* Unhash it, so that ancestors of killed async unlink + * files will be cleaned up during umount */ + return 1; + } + return 0; + +} + +/* + * Called when the dentry loses inode. + * We use it to clean up silly-renamed files. + */ +static void nfs_dentry_iput(struct dentry *dentry, struct inode *inode) +{ + if (dentry->d_flags & DCACHE_NFSFS_RENAMED) { + lock_kernel(); + inode->i_nlink--; + nfs_complete_unlink(dentry); + unlock_kernel(); + } + /* When creating a negative dentry, we want to renew d_time */ + nfs_renew_times(dentry); + iput(inode); +} + +struct dentry_operations nfs_dentry_operations = { + .d_revalidate = nfs_lookup_revalidate, + .d_delete = nfs_dentry_delete, + .d_iput = nfs_dentry_iput, +}; + +static inline +int nfs_is_exclusive_create(struct inode *dir, struct nameidata *nd) +{ + if (NFS_PROTO(dir)->version == 2) + return 0; + if (!nd || (nd->flags & LOOKUP_CONTINUE) || !(nd->flags & LOOKUP_CREATE)) + return 0; + return (nd->intent.open.flags & O_EXCL) != 0; +} + +static struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd) +{ + struct dentry *res; + struct inode *inode = NULL; + int error; + struct nfs_fh fhandle; + struct nfs_fattr fattr; + + dfprintk(VFS, "NFS: lookup(%s/%s)\n", + dentry->d_parent->d_name.name, dentry->d_name.name); + + res = ERR_PTR(-ENAMETOOLONG); + if (dentry->d_name.len > NFS_SERVER(dir)->namelen) + goto out; + + res = ERR_PTR(-ENOMEM); + dentry->d_op = NFS_PROTO(dir)->dentry_ops; + + lock_kernel(); + /* Revalidate parent directory attribute cache */ + error = nfs_revalidate_inode(NFS_SERVER(dir), dir); + if (error < 0) { + res = ERR_PTR(error); + goto out_unlock; + } + + /* If we're doing an exclusive create, optimize away the lookup */ + if (nfs_is_exclusive_create(dir, nd)) + goto no_entry; + + error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, &fhandle, &fattr); + if (error == -ENOENT) + goto no_entry; + if (error < 0) { + res = ERR_PTR(error); + goto out_unlock; + } + res = ERR_PTR(-EACCES); + inode = nfs_fhget(dentry->d_sb, &fhandle, &fattr); + if (!inode) + goto out_unlock; +no_entry: + res = d_add_unique(dentry, inode); + if (res != NULL) + dentry = res; + nfs_renew_times(dentry); + nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); +out_unlock: + unlock_kernel(); +out: + return res; +} + +#ifdef CONFIG_NFS_V4 +static int nfs_open_revalidate(struct dentry *, struct nameidata *); + +struct dentry_operations nfs4_dentry_operations = { + .d_revalidate = nfs_open_revalidate, + .d_delete = nfs_dentry_delete, + .d_iput = nfs_dentry_iput, +}; + +static int is_atomic_open(struct inode *dir, struct nameidata *nd) +{ + if (!nd) + return 0; + /* Check that we are indeed trying to open this file */ + if ((nd->flags & LOOKUP_CONTINUE) || !(nd->flags & LOOKUP_OPEN)) + return 0; + /* NFS does not (yet) have a stateful open for directories */ + if (nd->flags & LOOKUP_DIRECTORY) + return 0; + /* Are we trying to write to a read only partition? */ + if (IS_RDONLY(dir) && (nd->intent.open.flags & (O_CREAT|O_TRUNC|FMODE_WRITE))) + return 0; + return 1; +} + +static struct dentry *nfs_atomic_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd) +{ + struct dentry *res = NULL; + struct inode *inode = NULL; + int error; + + /* Check that we are indeed trying to open this file */ + if (!is_atomic_open(dir, nd)) + goto no_open; + + if (dentry->d_name.len > NFS_SERVER(dir)->namelen) { + res = ERR_PTR(-ENAMETOOLONG); + goto out; + } + dentry->d_op = NFS_PROTO(dir)->dentry_ops; + + /* Let vfs_create() deal with O_EXCL */ + if (nd->intent.open.flags & O_EXCL) + goto no_entry; + + /* Open the file on the server */ + lock_kernel(); + /* Revalidate parent directory attribute cache */ + error = nfs_revalidate_inode(NFS_SERVER(dir), dir); + if (error < 0) { + res = ERR_PTR(error); + goto out; + } + + if (nd->intent.open.flags & O_CREAT) { + nfs_begin_data_update(dir); + inode = nfs4_atomic_open(dir, dentry, nd); + nfs_end_data_update(dir); + } else + inode = nfs4_atomic_open(dir, dentry, nd); + unlock_kernel(); + if (IS_ERR(inode)) { + error = PTR_ERR(inode); + switch (error) { + /* Make a negative dentry */ + case -ENOENT: + inode = NULL; + break; + /* This turned out not to be a regular file */ + case -ELOOP: + if (!(nd->intent.open.flags & O_NOFOLLOW)) + goto no_open; + /* case -EISDIR: */ + /* case -EINVAL: */ + default: + res = ERR_PTR(error); + goto out; + } + } +no_entry: + res = d_add_unique(dentry, inode); + if (res != NULL) + dentry = res; + nfs_renew_times(dentry); + nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); +out: + return res; +no_open: + return nfs_lookup(dir, dentry, nd); +} + +static int nfs_open_revalidate(struct dentry *dentry, struct nameidata *nd) +{ + struct dentry *parent = NULL; + struct inode *inode = dentry->d_inode; + struct inode *dir; + unsigned long verifier; + int openflags, ret = 0; + + parent = dget_parent(dentry); + dir = parent->d_inode; + if (!is_atomic_open(dir, nd)) + goto no_open; + /* We can't create new files in nfs_open_revalidate(), so we + * optimize away revalidation of negative dentries. + */ + if (inode == NULL) + goto out; + /* NFS only supports OPEN on regular files */ + if (!S_ISREG(inode->i_mode)) + goto no_open; + openflags = nd->intent.open.flags; + /* We cannot do exclusive creation on a positive dentry */ + if ((openflags & (O_CREAT|O_EXCL)) == (O_CREAT|O_EXCL)) + goto no_open; + /* We can't create new files, or truncate existing ones here */ + openflags &= ~(O_CREAT|O_TRUNC); + + /* + * Note: we're not holding inode->i_sem and so may be racing with + * operations that change the directory. We therefore save the + * change attribute *before* we do the RPC call. + */ + lock_kernel(); + verifier = nfs_save_change_attribute(dir); + ret = nfs4_open_revalidate(dir, dentry, openflags); + if (!ret) + nfs_set_verifier(dentry, verifier); + unlock_kernel(); +out: + dput(parent); + if (!ret) + d_drop(dentry); + return ret; +no_open: + dput(parent); + if (inode != NULL && nfs_have_delegation(inode, FMODE_READ)) + return 1; + return nfs_lookup_revalidate(dentry, nd); +} +#endif /* CONFIG_NFSV4 */ + +static struct dentry *nfs_readdir_lookup(nfs_readdir_descriptor_t *desc) +{ + struct dentry *parent = desc->file->f_dentry; + struct inode *dir = parent->d_inode; + struct nfs_entry *entry = desc->entry; + struct dentry *dentry, *alias; + struct qstr name = { + .name = entry->name, + .len = entry->len, + }; + struct inode *inode; + + switch (name.len) { + case 2: + if (name.name[0] == '.' && name.name[1] == '.') + return dget_parent(parent); + break; + case 1: + if (name.name[0] == '.') + return dget(parent); + } + name.hash = full_name_hash(name.name, name.len); + dentry = d_lookup(parent, &name); + if (dentry != NULL) + return dentry; + if (!desc->plus || !(entry->fattr->valid & NFS_ATTR_FATTR)) + return NULL; + /* Note: caller is already holding the dir->i_sem! */ + dentry = d_alloc(parent, &name); + if (dentry == NULL) + return NULL; + dentry->d_op = NFS_PROTO(dir)->dentry_ops; + inode = nfs_fhget(dentry->d_sb, entry->fh, entry->fattr); + if (!inode) { + dput(dentry); + return NULL; + } + alias = d_add_unique(dentry, inode); + if (alias != NULL) { + dput(dentry); + dentry = alias; + } + nfs_renew_times(dentry); + nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); + return dentry; +} + +/* + * Code common to create, mkdir, and mknod. + */ +int nfs_instantiate(struct dentry *dentry, struct nfs_fh *fhandle, + struct nfs_fattr *fattr) +{ + struct inode *inode; + int error = -EACCES; + + /* We may have been initialized further down */ + if (dentry->d_inode) + return 0; + if (fhandle->size == 0) { + struct inode *dir = dentry->d_parent->d_inode; + error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr); + if (error) + goto out_err; + } + if (!(fattr->valid & NFS_ATTR_FATTR)) { + struct nfs_server *server = NFS_SB(dentry->d_sb); + error = server->rpc_ops->getattr(server, fhandle, fattr); + if (error < 0) + goto out_err; + } + error = -ENOMEM; + inode = nfs_fhget(dentry->d_sb, fhandle, fattr); + if (inode == NULL) + goto out_err; + d_instantiate(dentry, inode); + return 0; +out_err: + d_drop(dentry); + return error; +} + +/* + * Following a failed create operation, we drop the dentry rather + * than retain a negative dentry. This avoids a problem in the event + * that the operation succeeded on the server, but an error in the + * reply path made it appear to have failed. + */ +static int nfs_create(struct inode *dir, struct dentry *dentry, int mode, + struct nameidata *nd) +{ + struct iattr attr; + int error; + int open_flags = 0; + + dfprintk(VFS, "NFS: create(%s/%ld, %s\n", dir->i_sb->s_id, + dir->i_ino, dentry->d_name.name); + + attr.ia_mode = mode; + attr.ia_valid = ATTR_MODE; + + if (nd && (nd->flags & LOOKUP_CREATE)) + open_flags = nd->intent.open.flags; + + lock_kernel(); + nfs_begin_data_update(dir); + error = NFS_PROTO(dir)->create(dir, dentry, &attr, open_flags); + nfs_end_data_update(dir); + if (error != 0) + goto out_err; + nfs_renew_times(dentry); + nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); + unlock_kernel(); + return 0; +out_err: + unlock_kernel(); + d_drop(dentry); + return error; +} + +/* + * See comments for nfs_proc_create regarding failed operations. + */ +static int +nfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t rdev) +{ + struct iattr attr; + int status; + + dfprintk(VFS, "NFS: mknod(%s/%ld, %s\n", dir->i_sb->s_id, + dir->i_ino, dentry->d_name.name); + + if (!new_valid_dev(rdev)) + return -EINVAL; + + attr.ia_mode = mode; + attr.ia_valid = ATTR_MODE; + + lock_kernel(); + nfs_begin_data_update(dir); + status = NFS_PROTO(dir)->mknod(dir, dentry, &attr, rdev); + nfs_end_data_update(dir); + if (status != 0) + goto out_err; + nfs_renew_times(dentry); + nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); + unlock_kernel(); + return 0; +out_err: + unlock_kernel(); + d_drop(dentry); + return status; +} + +/* + * See comments for nfs_proc_create regarding failed operations. + */ +static int nfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) +{ + struct iattr attr; + int error; + + dfprintk(VFS, "NFS: mkdir(%s/%ld, %s\n", dir->i_sb->s_id, + dir->i_ino, dentry->d_name.name); + + attr.ia_valid = ATTR_MODE; + attr.ia_mode = mode | S_IFDIR; + + lock_kernel(); + nfs_begin_data_update(dir); + error = NFS_PROTO(dir)->mkdir(dir, dentry, &attr); + nfs_end_data_update(dir); + if (error != 0) + goto out_err; + nfs_renew_times(dentry); + nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); + unlock_kernel(); + return 0; +out_err: + d_drop(dentry); + unlock_kernel(); + return error; +} + +static int nfs_rmdir(struct inode *dir, struct dentry *dentry) +{ + int error; + + dfprintk(VFS, "NFS: rmdir(%s/%ld, %s\n", dir->i_sb->s_id, + dir->i_ino, dentry->d_name.name); + + lock_kernel(); + nfs_begin_data_update(dir); + error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name); + /* Ensure the VFS deletes this inode */ + if (error == 0 && dentry->d_inode != NULL) + dentry->d_inode->i_nlink = 0; + nfs_end_data_update(dir); + unlock_kernel(); + + return error; +} + +static int nfs_sillyrename(struct inode *dir, struct dentry *dentry) +{ + static unsigned int sillycounter; + const int i_inosize = sizeof(dir->i_ino)*2; + const int countersize = sizeof(sillycounter)*2; + const int slen = sizeof(".nfs") + i_inosize + countersize - 1; + char silly[slen+1]; + struct qstr qsilly; + struct dentry *sdentry; + int error = -EIO; + + dfprintk(VFS, "NFS: silly-rename(%s/%s, ct=%d)\n", + dentry->d_parent->d_name.name, dentry->d_name.name, + atomic_read(&dentry->d_count)); + +#ifdef NFS_PARANOIA +if (!dentry->d_inode) +printk("NFS: silly-renaming %s/%s, negative dentry??\n", +dentry->d_parent->d_name.name, dentry->d_name.name); +#endif + /* + * We don't allow a dentry to be silly-renamed twice. + */ + error = -EBUSY; + if (dentry->d_flags & DCACHE_NFSFS_RENAMED) + goto out; + + sprintf(silly, ".nfs%*.*lx", + i_inosize, i_inosize, dentry->d_inode->i_ino); + + sdentry = NULL; + do { + char *suffix = silly + slen - countersize; + + dput(sdentry); + sillycounter++; + sprintf(suffix, "%*.*x", countersize, countersize, sillycounter); + + dfprintk(VFS, "trying to rename %s to %s\n", + dentry->d_name.name, 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(sdentry->d_inode != NULL); /* need negative lookup */ + + qsilly.name = silly; + qsilly.len = strlen(silly); + nfs_begin_data_update(dir); + if (dentry->d_inode) { + nfs_begin_data_update(dentry->d_inode); + error = NFS_PROTO(dir)->rename(dir, &dentry->d_name, + dir, &qsilly); + nfs_end_data_update(dentry->d_inode); + } else + error = NFS_PROTO(dir)->rename(dir, &dentry->d_name, + dir, &qsilly); + nfs_end_data_update(dir); + if (!error) { + nfs_renew_times(dentry); + nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); + d_move(dentry, sdentry); + error = nfs_async_unlink(dentry); + /* If we return 0 we don't unlink */ + } + dput(sdentry); +out: + return error; +} + +/* + * Remove a file after making sure there are no pending writes, + * and after checking that the file has only one user. + * + * We invalidate the attribute cache and free the inode prior to the operation + * to avoid possible races if the server reuses the inode. + */ +static int nfs_safe_remove(struct dentry *dentry) +{ + struct inode *dir = dentry->d_parent->d_inode; + struct inode *inode = dentry->d_inode; + int error = -EBUSY; + + dfprintk(VFS, "NFS: safe_remove(%s/%s)\n", + dentry->d_parent->d_name.name, dentry->d_name.name); + + /* If the dentry was sillyrenamed, we simply call d_delete() */ + if (dentry->d_flags & DCACHE_NFSFS_RENAMED) { + error = 0; + goto out; + } + + nfs_begin_data_update(dir); + if (inode != NULL) { + nfs_begin_data_update(inode); + error = NFS_PROTO(dir)->remove(dir, &dentry->d_name); + /* The VFS may want to delete this inode */ + if (error == 0) + inode->i_nlink--; + nfs_end_data_update(inode); + } else + error = NFS_PROTO(dir)->remove(dir, &dentry->d_name); + nfs_end_data_update(dir); +out: + return error; +} + +/* We do silly rename. In case sillyrename() returns -EBUSY, the inode + * belongs to an active ".nfs..." file and we return -EBUSY. + * + * If sillyrename() returns 0, we do nothing, otherwise we unlink. + */ +static int nfs_unlink(struct inode *dir, struct dentry *dentry) +{ + int error; + int need_rehash = 0; + + dfprintk(VFS, "NFS: unlink(%s/%ld, %s)\n", dir->i_sb->s_id, + dir->i_ino, dentry->d_name.name); + + lock_kernel(); + spin_lock(&dcache_lock); + spin_lock(&dentry->d_lock); + if (atomic_read(&dentry->d_count) > 1) { + spin_unlock(&dentry->d_lock); + spin_unlock(&dcache_lock); + error = nfs_sillyrename(dir, dentry); + unlock_kernel(); + return error; + } + if (!d_unhashed(dentry)) { + __d_drop(dentry); + need_rehash = 1; + } + spin_unlock(&dentry->d_lock); + spin_unlock(&dcache_lock); + error = nfs_safe_remove(dentry); + if (!error) { + nfs_renew_times(dentry); + nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); + } else if (need_rehash) + d_rehash(dentry); + unlock_kernel(); + return error; +} + +static int +nfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname) +{ + struct iattr attr; + struct nfs_fattr sym_attr; + struct nfs_fh sym_fh; + struct qstr qsymname; + int error; + + dfprintk(VFS, "NFS: symlink(%s/%ld, %s, %s)\n", dir->i_sb->s_id, + dir->i_ino, dentry->d_name.name, symname); + +#ifdef NFS_PARANOIA +if (dentry->d_inode) +printk("nfs_proc_symlink: %s/%s not negative!\n", +dentry->d_parent->d_name.name, dentry->d_name.name); +#endif + /* + * Fill in the sattr for the call. + * Note: SunOS 4.1.2 crashes if the mode isn't initialized! + */ + attr.ia_valid = ATTR_MODE; + attr.ia_mode = S_IFLNK | S_IRWXUGO; + + qsymname.name = symname; + qsymname.len = strlen(symname); + + lock_kernel(); + nfs_begin_data_update(dir); + error = NFS_PROTO(dir)->symlink(dir, &dentry->d_name, &qsymname, + &attr, &sym_fh, &sym_attr); + nfs_end_data_update(dir); + if (!error) { + error = nfs_instantiate(dentry, &sym_fh, &sym_attr); + } else { + if (error == -EEXIST) + printk("nfs_proc_symlink: %s/%s already exists??\n", + dentry->d_parent->d_name.name, dentry->d_name.name); + d_drop(dentry); + } + unlock_kernel(); + return error; +} + +static int +nfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) +{ + struct inode *inode = old_dentry->d_inode; + int error; + + dfprintk(VFS, "NFS: link(%s/%s -> %s/%s)\n", + old_dentry->d_parent->d_name.name, old_dentry->d_name.name, + dentry->d_parent->d_name.name, dentry->d_name.name); + + /* + * Drop the dentry in advance to force a new lookup. + * Since nfs_proc_link doesn't return a file handle, + * we can't use the existing dentry. + */ + lock_kernel(); + d_drop(dentry); + + nfs_begin_data_update(dir); + nfs_begin_data_update(inode); + error = NFS_PROTO(dir)->link(inode, dir, &dentry->d_name); + nfs_end_data_update(inode); + nfs_end_data_update(dir); + unlock_kernel(); + return error; +} + +/* + * RENAME + * FIXME: Some nfsds, like the Linux user space nfsd, may generate a + * different file handle for the same inode after a rename (e.g. when + * moving to a different directory). A fail-safe method to do so would + * be to look up old_dir/old_name, create a link to new_dir/new_name and + * rename the old file using the sillyrename stuff. This way, the original + * file in old_dir will go away when the last process iput()s the inode. + * + * FIXED. + * + * It actually works quite well. One needs to have the possibility for + * at least one ".nfs..." file in each directory the file ever gets + * moved or linked to which happens automagically with the new + * implementation that only depends on the dcache stuff instead of + * using the inode layer + * + * Unfortunately, things are a little more complicated than indicated + * above. For a cross-directory move, we want to make sure we can get + * rid of the old inode after the operation. This means there must be + * no pending writes (if it's a file), and the use count must be 1. + * If these conditions are met, we can drop the dentries before doing + * the rename. + */ +static int nfs_rename(struct inode *old_dir, struct dentry *old_dentry, + struct inode *new_dir, struct dentry *new_dentry) +{ + struct inode *old_inode = old_dentry->d_inode; + struct inode *new_inode = new_dentry->d_inode; + struct dentry *dentry = NULL, *rehash = NULL; + int error = -EBUSY; + + /* + * To prevent any new references to the target during the rename, + * we unhash the dentry and free the inode in advance. + */ + lock_kernel(); + if (!d_unhashed(new_dentry)) { + d_drop(new_dentry); + rehash = new_dentry; + } + + dfprintk(VFS, "NFS: rename(%s/%s -> %s/%s, ct=%d)\n", + old_dentry->d_parent->d_name.name, old_dentry->d_name.name, + new_dentry->d_parent->d_name.name, new_dentry->d_name.name, + atomic_read(&new_dentry->d_count)); + + /* + * First check whether the target is busy ... we can't + * safely do _any_ rename if the target is in use. + * + * For files, make a copy of the dentry and then do a + * silly-rename. If the silly-rename succeeds, the + * copied dentry is hashed and becomes the new target. + */ + if (!new_inode) + goto go_ahead; + if (S_ISDIR(new_inode->i_mode)) + goto out; + else if (atomic_read(&new_dentry->d_count) > 2) { + int err; + /* copy the target dentry's name */ + dentry = d_alloc(new_dentry->d_parent, + &new_dentry->d_name); + if (!dentry) + goto out; + + /* silly-rename the existing target ... */ + err = nfs_sillyrename(new_dir, new_dentry); + if (!err) { + new_dentry = rehash = dentry; + new_inode = NULL; + /* instantiate the replacement target */ + d_instantiate(new_dentry, NULL); + } else if (atomic_read(&new_dentry->d_count) > 1) { + /* dentry still busy? */ +#ifdef NFS_PARANOIA + printk("nfs_rename: target %s/%s busy, d_count=%d\n", + new_dentry->d_parent->d_name.name, + new_dentry->d_name.name, + atomic_read(&new_dentry->d_count)); +#endif + goto out; + } + } + +go_ahead: + /* + * ... prune child dentries and writebacks if needed. + */ + if (atomic_read(&old_dentry->d_count) > 1) { + nfs_wb_all(old_inode); + shrink_dcache_parent(old_dentry); + } + + if (new_inode) + d_delete(new_dentry); + + nfs_begin_data_update(old_dir); + nfs_begin_data_update(new_dir); + nfs_begin_data_update(old_inode); + error = NFS_PROTO(old_dir)->rename(old_dir, &old_dentry->d_name, + new_dir, &new_dentry->d_name); + nfs_end_data_update(old_inode); + nfs_end_data_update(new_dir); + nfs_end_data_update(old_dir); +out: + if (rehash) + d_rehash(rehash); + if (!error) { + if (!S_ISDIR(old_inode->i_mode)) + d_move(old_dentry, new_dentry); + nfs_renew_times(new_dentry); + nfs_set_verifier(new_dentry, nfs_save_change_attribute(new_dir)); + } + + /* new dentry created? */ + if (dentry) + dput(dentry); + unlock_kernel(); + return error; +} + +int nfs_access_get_cached(struct inode *inode, struct rpc_cred *cred, struct nfs_access_entry *res) +{ + struct nfs_access_entry *cache = &NFS_I(inode)->cache_access; + + if (cache->cred != cred + || time_after(jiffies, cache->jiffies + NFS_ATTRTIMEO(inode)) + || (NFS_FLAGS(inode) & NFS_INO_INVALID_ACCESS)) + return -ENOENT; + memcpy(res, cache, sizeof(*res)); + return 0; +} + +void nfs_access_add_cache(struct inode *inode, struct nfs_access_entry *set) +{ + struct nfs_access_entry *cache = &NFS_I(inode)->cache_access; + + if (cache->cred != set->cred) { + if (cache->cred) + put_rpccred(cache->cred); + cache->cred = get_rpccred(set->cred); + } + NFS_FLAGS(inode) &= ~NFS_INO_INVALID_ACCESS; + cache->jiffies = set->jiffies; + cache->mask = set->mask; +} + +static int nfs_do_access(struct inode *inode, struct rpc_cred *cred, int mask) +{ + struct nfs_access_entry cache; + int status; + + status = nfs_access_get_cached(inode, cred, &cache); + if (status == 0) + goto out; + + /* Be clever: ask server to check for all possible rights */ + cache.mask = MAY_EXEC | MAY_WRITE | MAY_READ; + cache.cred = cred; + cache.jiffies = jiffies; + status = NFS_PROTO(inode)->access(inode, &cache); + if (status != 0) + return status; + nfs_access_add_cache(inode, &cache); +out: + if ((cache.mask & mask) == mask) + return 0; + return -EACCES; +} + +int nfs_permission(struct inode *inode, int mask, struct nameidata *nd) +{ + struct rpc_cred *cred; + int res = 0; + + if (mask == 0) + goto out; + /* Is this sys_access() ? */ + if (nd != NULL && (nd->flags & LOOKUP_ACCESS)) + goto force_lookup; + + switch (inode->i_mode & S_IFMT) { + case S_IFLNK: + goto out; + case S_IFREG: + /* NFSv4 has atomic_open... */ + if (nfs_server_capable(inode, NFS_CAP_ATOMIC_OPEN) + && nd != NULL + && (nd->flags & LOOKUP_OPEN)) + goto out; + break; + case S_IFDIR: + /* + * Optimize away all write operations, since the server + * will check permissions when we perform the op. + */ + if ((mask & MAY_WRITE) && !(mask & MAY_READ)) + goto out; + } + +force_lookup: + lock_kernel(); + + if (!NFS_PROTO(inode)->access) + goto out_notsup; + + cred = rpcauth_lookupcred(NFS_CLIENT(inode)->cl_auth, 0); + if (!IS_ERR(cred)) { + res = nfs_do_access(inode, cred, mask); + put_rpccred(cred); + } else + res = PTR_ERR(cred); + unlock_kernel(); +out: + return res; +out_notsup: + res = nfs_revalidate_inode(NFS_SERVER(inode), inode); + if (res == 0) + res = generic_permission(inode, mask, NULL); + unlock_kernel(); + return res; +} + +/* + * Local variables: + * version-control: t + * kept-new-versions: 5 + * End: + */ |