diff options
| -rw-r--r-- | fs/nfs/dir.c | 86 |
1 files changed, 68 insertions, 18 deletions
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index affd3ae..b483e5d 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -30,6 +30,7 @@ #include <linux/nfs_mount.h> #include <linux/pagemap.h> #include <linux/smp_lock.h> +#include <linux/pagevec.h> #include <linux/namei.h> #include <linux/mount.h> @@ -1441,39 +1442,88 @@ static int nfs_unlink(struct inode *dir, struct dentry *dentry) return error; } -static int -nfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname) +/* + * To create a symbolic link, most file systems instantiate a new inode, + * add a page to it containing the path, then write it out to the disk + * using prepare_write/commit_write. + * + * Unfortunately the NFS client can't create the in-core inode first + * because it needs a file handle to create an in-core inode (see + * fs/nfs/inode.c:nfs_fhget). We only have a file handle *after* the + * symlink request has completed on the server. + * + * So instead we allocate a raw page, copy the symname into it, then do + * the SYMLINK request with the page as the buffer. If it succeeds, we + * now have a new file handle and can instantiate an in-core NFS inode + * and move the raw page into its mapping. + */ +static int nfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname) { + struct pagevec lru_pvec; + struct page *page; + char *kaddr; struct iattr attr; - struct qstr qsymname; + unsigned int pathlen = strlen(symname); + struct qstr qsymname = { + .name = symname, + .len = pathlen, + }; 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; + if (pathlen > PAGE_SIZE) + return -ENAMETOOLONG; - qsymname.name = symname; - qsymname.len = strlen(symname); + attr.ia_mode = S_IFLNK | S_IRWXUGO; + attr.ia_valid = ATTR_MODE; lock_kernel(); + + page = alloc_page(GFP_KERNEL); + if (!page) { + unlock_kernel(); + return -ENOMEM; + } + + kaddr = kmap_atomic(page, KM_USER0); + memcpy(kaddr, symname, pathlen); + if (pathlen < PAGE_SIZE) + memset(kaddr + pathlen, 0, PAGE_SIZE - pathlen); + kunmap_atomic(kaddr, KM_USER0); + + /* XXX: eventually this will pass in {page, pathlen}, + * instead of qsymname; need XDR changes for that */ nfs_begin_data_update(dir); error = NFS_PROTO(dir)->symlink(dir, dentry, &qsymname, &attr); nfs_end_data_update(dir); - if (!error) + if (error != 0) { + dfprintk(VFS, "NFS: symlink(%s/%ld, %s, %s) error %d\n", + dir->i_sb->s_id, dir->i_ino, + dentry->d_name.name, symname, error); d_drop(dentry); + __free_page(page); + unlock_kernel(); + return error; + } + + /* + * No big deal if we can't add this page to the page cache here. + * READLINK will get the missing page from the server if needed. + */ + pagevec_init(&lru_pvec, 0); + if (!add_to_page_cache(page, dentry->d_inode->i_mapping, 0, + GFP_KERNEL)) { + if (!pagevec_add(&lru_pvec, page)) + __pagevec_lru_add(&lru_pvec); + SetPageUptodate(page); + unlock_page(page); + } else + __free_page(page); + unlock_kernel(); - return error; + return 0; } static int |
