diff options
Diffstat (limited to 'fs/reiserfs/xattr.c')
| -rw-r--r-- | fs/reiserfs/xattr.c | 1450 |
1 files changed, 1450 insertions, 0 deletions
diff --git a/fs/reiserfs/xattr.c b/fs/reiserfs/xattr.c new file mode 100644 index 00000000000..45582fe8b46 --- /dev/null +++ b/fs/reiserfs/xattr.c @@ -0,0 +1,1450 @@ +/* + * linux/fs/reiserfs/xattr.c + * + * Copyright (c) 2002 by Jeff Mahoney, <jeffm@suse.com> + * + */ + +/* + * In order to implement EA/ACLs in a clean, backwards compatible manner, + * they are implemented as files in a "private" directory. + * Each EA is in it's own file, with the directory layout like so (/ is assumed + * to be relative to fs root). Inside the /.reiserfs_priv/xattrs directory, + * directories named using the capital-hex form of the objectid and + * generation number are used. Inside each directory are individual files + * named with the name of the extended attribute. + * + * So, for objectid 12648430, we could have: + * /.reiserfs_priv/xattrs/C0FFEE.0/system.posix_acl_access + * /.reiserfs_priv/xattrs/C0FFEE.0/system.posix_acl_default + * /.reiserfs_priv/xattrs/C0FFEE.0/user.Content-Type + * .. or similar. + * + * The file contents are the text of the EA. The size is known based on the + * stat data describing the file. + * + * In the case of system.posix_acl_access and system.posix_acl_default, since + * these are special cases for filesystem ACLs, they are interpreted by the + * kernel, in addition, they are negatively and positively cached and attached + * to the inode so that unnecessary lookups are avoided. + */ + +#include <linux/reiserfs_fs.h> +#include <linux/dcache.h> +#include <linux/namei.h> +#include <linux/errno.h> +#include <linux/fs.h> +#include <linux/file.h> +#include <linux/pagemap.h> +#include <linux/xattr.h> +#include <linux/reiserfs_xattr.h> +#include <linux/reiserfs_acl.h> +#include <linux/mbcache.h> +#include <asm/uaccess.h> +#include <asm/checksum.h> +#include <linux/smp_lock.h> +#include <linux/stat.h> +#include <asm/semaphore.h> + +#define FL_READONLY 128 +#define FL_DIR_SEM_HELD 256 +#define PRIVROOT_NAME ".reiserfs_priv" +#define XAROOT_NAME "xattrs" + +static struct reiserfs_xattr_handler *find_xattr_handler_prefix (const char *prefix); + +static struct dentry * +create_xa_root (struct super_block *sb) +{ + struct dentry *privroot = dget (REISERFS_SB(sb)->priv_root); + struct dentry *xaroot; + + /* This needs to be created at mount-time */ + if (!privroot) + return ERR_PTR(-EOPNOTSUPP); + + xaroot = lookup_one_len (XAROOT_NAME, privroot, strlen (XAROOT_NAME)); + if (IS_ERR (xaroot)) { + goto out; + } else if (!xaroot->d_inode) { + int err; + down (&privroot->d_inode->i_sem); + err = privroot->d_inode->i_op->mkdir (privroot->d_inode, xaroot, 0700); + up (&privroot->d_inode->i_sem); + + if (err) { + dput (xaroot); + dput (privroot); + return ERR_PTR (err); + } + REISERFS_SB(sb)->xattr_root = dget (xaroot); + } + +out: + dput (privroot); + return xaroot; +} + +/* This will return a dentry, or error, refering to the xa root directory. + * If the xa root doesn't exist yet, the dentry will be returned without + * an associated inode. This dentry can be used with ->mkdir to create + * the xa directory. */ +static struct dentry * +__get_xa_root (struct super_block *s) +{ + struct dentry *privroot = dget (REISERFS_SB(s)->priv_root); + struct dentry *xaroot = NULL; + + if (IS_ERR (privroot) || !privroot) + return privroot; + + xaroot = lookup_one_len (XAROOT_NAME, privroot, strlen (XAROOT_NAME)); + if (IS_ERR (xaroot)) { + goto out; + } else if (!xaroot->d_inode) { + dput (xaroot); + xaroot = NULL; + goto out; + } + + REISERFS_SB(s)->xattr_root = dget (xaroot); + +out: + dput (privroot); + return xaroot; +} + +/* Returns the dentry (or NULL) referring to the root of the extended + * attribute directory tree. If it has already been retreived, it is used. + * Otherwise, we attempt to retreive it from disk. It may also return + * a pointer-encoded error. + */ +static inline struct dentry * +get_xa_root (struct super_block *s) +{ + struct dentry *dentry = dget (REISERFS_SB(s)->xattr_root); + + if (!dentry) + dentry = __get_xa_root (s); + + return dentry; +} + +/* Opens the directory corresponding to the inode's extended attribute store. + * If flags allow, the tree to the directory may be created. If creation is + * prohibited, -ENODATA is returned. */ +static struct dentry * +open_xa_dir (const struct inode *inode, int flags) +{ + struct dentry *xaroot, *xadir; + char namebuf[17]; + + xaroot = get_xa_root (inode->i_sb); + if (IS_ERR (xaroot)) { + return xaroot; + } else if (!xaroot) { + if (flags == 0 || flags & XATTR_CREATE) { + xaroot = create_xa_root (inode->i_sb); + if (IS_ERR (xaroot)) + return xaroot; + } + if (!xaroot) + return ERR_PTR (-ENODATA); + } + + /* ok, we have xaroot open */ + + snprintf (namebuf, sizeof (namebuf), "%X.%X", + le32_to_cpu (INODE_PKEY (inode)->k_objectid), + inode->i_generation); + xadir = lookup_one_len (namebuf, xaroot, strlen (namebuf)); + if (IS_ERR (xadir)) { + dput (xaroot); + return xadir; + } + + if (!xadir->d_inode) { + int err; + if (flags == 0 || flags & XATTR_CREATE) { + /* Although there is nothing else trying to create this directory, + * another directory with the same hash may be created, so we need + * to protect against that */ + err = xaroot->d_inode->i_op->mkdir (xaroot->d_inode, xadir, 0700); + if (err) { + dput (xaroot); + dput (xadir); + return ERR_PTR (err); + } + } + if (!xadir->d_inode) { + dput (xaroot); + dput (xadir); + return ERR_PTR (-ENODATA); + } + } + + dput (xaroot); + return xadir; +} + +/* Returns a dentry corresponding to a specific extended attribute file + * for the inode. If flags allow, the file is created. Otherwise, a + * valid or negative dentry, or an error is returned. */ +static struct dentry * +get_xa_file_dentry (const struct inode *inode, const char *name, int flags) +{ + struct dentry *xadir, *xafile; + int err = 0; + + xadir = open_xa_dir (inode, flags); + if (IS_ERR (xadir)) { + return ERR_PTR (PTR_ERR (xadir)); + } else if (xadir && !xadir->d_inode) { + dput (xadir); + return ERR_PTR (-ENODATA); + } + + xafile = lookup_one_len (name, xadir, strlen (name)); + if (IS_ERR (xafile)) { + dput (xadir); + return ERR_PTR (PTR_ERR (xafile)); + } + + if (xafile->d_inode) { /* file exists */ + if (flags & XATTR_CREATE) { + err = -EEXIST; + dput (xafile); + goto out; + } + } else if (flags & XATTR_REPLACE || flags & FL_READONLY) { + goto out; + } else { + /* inode->i_sem is down, so nothing else can try to create + * the same xattr */ + err = xadir->d_inode->i_op->create (xadir->d_inode, xafile, + 0700|S_IFREG, NULL); + + if (err) { + dput (xafile); + goto out; + } + } + +out: + dput (xadir); + if (err) + xafile = ERR_PTR (err); + return xafile; +} + + +/* Opens a file pointer to the attribute associated with inode */ +static struct file * +open_xa_file (const struct inode *inode, const char *name, int flags) +{ + struct dentry *xafile; + struct file *fp; + + xafile = get_xa_file_dentry (inode, name, flags); + if (IS_ERR (xafile)) + return ERR_PTR (PTR_ERR (xafile)); + else if (!xafile->d_inode) { + dput (xafile); + return ERR_PTR (-ENODATA); + } + + fp = dentry_open (xafile, NULL, O_RDWR); + /* dentry_open dputs the dentry if it fails */ + + return fp; +} + + +/* + * this is very similar to fs/reiserfs/dir.c:reiserfs_readdir, but + * we need to drop the path before calling the filldir struct. That + * would be a big performance hit to the non-xattr case, so I've copied + * the whole thing for now. --clm + * + * the big difference is that I go backwards through the directory, + * and don't mess with f->f_pos, but the idea is the same. Do some + * action on each and every entry in the directory. + * + * we're called with i_sem held, so there are no worries about the directory + * changing underneath us. + */ +static int __xattr_readdir(struct file * filp, void * dirent, filldir_t filldir) +{ + struct inode *inode = filp->f_dentry->d_inode; + struct cpu_key pos_key; /* key of current position in the directory (key of directory entry) */ + INITIALIZE_PATH (path_to_entry); + struct buffer_head * bh; + int entry_num; + struct item_head * ih, tmp_ih; + int search_res; + char * local_buf; + loff_t next_pos; + char small_buf[32] ; /* avoid kmalloc if we can */ + struct reiserfs_de_head *deh; + int d_reclen; + char * d_name; + off_t d_off; + ino_t d_ino; + struct reiserfs_dir_entry de; + + + /* form key for search the next directory entry using f_pos field of + file structure */ + next_pos = max_reiserfs_offset(inode); + + while (1) { +research: + if (next_pos <= DOT_DOT_OFFSET) + break; + make_cpu_key (&pos_key, inode, next_pos, TYPE_DIRENTRY, 3); + + search_res = search_by_entry_key(inode->i_sb, &pos_key, &path_to_entry, &de); + if (search_res == IO_ERROR) { + // FIXME: we could just skip part of directory which could + // not be read + pathrelse(&path_to_entry); + return -EIO; + } + + if (search_res == NAME_NOT_FOUND) + de.de_entry_num--; + + set_de_name_and_namelen(&de); + entry_num = de.de_entry_num; + deh = &(de.de_deh[entry_num]); + + bh = de.de_bh; + ih = de.de_ih; + + if (!is_direntry_le_ih(ih)) { + reiserfs_warning(inode->i_sb, "not direntry %h", ih); + break; + } + copy_item_head(&tmp_ih, ih); + + /* we must have found item, that is item of this directory, */ + RFALSE( COMP_SHORT_KEYS (&(ih->ih_key), &pos_key), + "vs-9000: found item %h does not match to dir we readdir %K", + ih, &pos_key); + + if (deh_offset(deh) <= DOT_DOT_OFFSET) { + break; + } + + /* look for the previous entry in the directory */ + next_pos = deh_offset (deh) - 1; + + if (!de_visible (deh)) + /* it is hidden entry */ + continue; + + d_reclen = entry_length(bh, ih, entry_num); + d_name = B_I_DEH_ENTRY_FILE_NAME (bh, ih, deh); + d_off = deh_offset (deh); + d_ino = deh_objectid (deh); + + if (!d_name[d_reclen - 1]) + d_reclen = strlen (d_name); + + if (d_reclen > REISERFS_MAX_NAME(inode->i_sb->s_blocksize)){ + /* too big to send back to VFS */ + continue ; + } + + /* Ignore the .reiserfs_priv entry */ + if (reiserfs_xattrs (inode->i_sb) && + !old_format_only(inode->i_sb) && + deh_objectid (deh) == le32_to_cpu (INODE_PKEY(REISERFS_SB(inode->i_sb)->priv_root->d_inode)->k_objectid)) + continue; + + if (d_reclen <= 32) { + local_buf = small_buf ; + } else { + local_buf = reiserfs_kmalloc(d_reclen, GFP_NOFS, inode->i_sb) ; + if (!local_buf) { + pathrelse (&path_to_entry); + return -ENOMEM ; + } + if (item_moved (&tmp_ih, &path_to_entry)) { + reiserfs_kfree(local_buf, d_reclen, inode->i_sb) ; + + /* sigh, must retry. Do this same offset again */ + next_pos = d_off; + goto research; + } + } + + // Note, that we copy name to user space via temporary + // buffer (local_buf) because filldir will block if + // user space buffer is swapped out. At that time + // entry can move to somewhere else + memcpy (local_buf, d_name, d_reclen); + + /* the filldir function might need to start transactions, + * or do who knows what. Release the path now that we've + * copied all the important stuff out of the deh + */ + pathrelse (&path_to_entry); + + if (filldir (dirent, local_buf, d_reclen, d_off, d_ino, + DT_UNKNOWN) < 0) { + if (local_buf != small_buf) { + reiserfs_kfree(local_buf, d_reclen, inode->i_sb) ; + } + goto end; + } + if (local_buf != small_buf) { + reiserfs_kfree(local_buf, d_reclen, inode->i_sb) ; + } + } /* while */ + +end: + pathrelse (&path_to_entry); + return 0; +} + +/* + * this could be done with dedicated readdir ops for the xattr files, + * but I want to get something working asap + * this is stolen from vfs_readdir + * + */ +static +int xattr_readdir(struct file *file, filldir_t filler, void *buf) +{ + struct inode *inode = file->f_dentry->d_inode; + int res = -ENOTDIR; + if (!file->f_op || !file->f_op->readdir) + goto out; + down(&inode->i_sem); +// down(&inode->i_zombie); + res = -ENOENT; + if (!IS_DEADDIR(inode)) { + lock_kernel(); + res = __xattr_readdir(file, buf, filler); + unlock_kernel(); + } +// up(&inode->i_zombie); + up(&inode->i_sem); +out: + return res; +} + + +/* Internal operations on file data */ +static inline void +reiserfs_put_page(struct page *page) +{ + kunmap(page); + page_cache_release(page); +} + +static struct page * +reiserfs_get_page(struct inode *dir, unsigned long n) +{ + struct address_space *mapping = dir->i_mapping; + struct page *page; + /* We can deadlock if we try to free dentries, + and an unlink/rmdir has just occured - GFP_NOFS avoids this */ + mapping->flags = (mapping->flags & ~__GFP_BITS_MASK) | GFP_NOFS; + page = read_cache_page (mapping, n, + (filler_t*)mapping->a_ops->readpage, NULL); + if (!IS_ERR(page)) { + wait_on_page_locked(page); + kmap(page); + if (!PageUptodate(page)) + goto fail; + + if (PageError(page)) + goto fail; + } + return page; + +fail: + reiserfs_put_page(page); + return ERR_PTR(-EIO); +} + +static inline __u32 +xattr_hash (const char *msg, int len) +{ + return csum_partial (msg, len, 0); +} + +/* Generic extended attribute operations that can be used by xa plugins */ + +/* + * inode->i_sem: down + */ +int +reiserfs_xattr_set (struct inode *inode, const char *name, const void *buffer, + size_t buffer_size, int flags) +{ + int err = 0; + struct file *fp; + struct page *page; + char *data; + struct address_space *mapping; + size_t file_pos = 0; + size_t buffer_pos = 0; + struct inode *xinode; + struct iattr newattrs; + __u32 xahash = 0; + + if (IS_RDONLY (inode)) + return -EROFS; + + if (IS_IMMUTABLE (inode) || IS_APPEND (inode)) + return -EPERM; + + if (get_inode_sd_version (inode) == STAT_DATA_V1) + return -EOPNOTSUPP; + + /* Empty xattrs are ok, they're just empty files, no hash */ + if (buffer && buffer_size) + xahash = xattr_hash (buffer, buffer_size); + +open_file: + fp = open_xa_file (inode, name, flags); + if (IS_ERR (fp)) { + err = PTR_ERR (fp); + goto out; + } + + xinode = fp->f_dentry->d_inode; + REISERFS_I(inode)->i_flags |= i_has_xattr_dir; + + /* we need to copy it off.. */ + if (xinode->i_nlink > 1) { + fput(fp); + err = reiserfs_xattr_del (inode, name); + if (err < 0) + goto out; + /* We just killed the old one, we're not replacing anymore */ + if (flags & XATTR_REPLACE) + flags &= ~XATTR_REPLACE; + goto open_file; + } + + /* Resize it so we're ok to write there */ + newattrs.ia_size = buffer_size; + newattrs.ia_valid = ATTR_SIZE | ATTR_CTIME; + down (&xinode->i_sem); + err = notify_change(fp->f_dentry, &newattrs); + if (err) + goto out_filp; + + mapping = xinode->i_mapping; + while (buffer_pos < buffer_size || buffer_pos == 0) { + size_t chunk; + size_t skip = 0; + size_t page_offset = (file_pos & (PAGE_CACHE_SIZE - 1)); + if (buffer_size - buffer_pos > PAGE_CACHE_SIZE) + chunk = PAGE_CACHE_SIZE; + else + chunk = buffer_size - buffer_pos; + + page = reiserfs_get_page (xinode, file_pos >> PAGE_CACHE_SHIFT); + if (IS_ERR (page)) { + err = PTR_ERR (page); + goto out_filp; + } + + lock_page (page); + data = page_address (page); + + if (file_pos == 0) { + struct reiserfs_xattr_header *rxh; + skip = file_pos = sizeof (struct reiserfs_xattr_header); + if (chunk + skip > PAGE_CACHE_SIZE) + chunk = PAGE_CACHE_SIZE - skip; + rxh = (struct reiserfs_xattr_header *)data; + rxh->h_magic = cpu_to_le32 (REISERFS_XATTR_MAGIC); + rxh->h_hash = cpu_to_le32 (xahash); + } + + err = mapping->a_ops->prepare_write (fp, page, page_offset, + page_offset + chunk + skip); + if (!err) { + if (buffer) + memcpy (data + skip, buffer + buffer_pos, chunk); + err = mapping->a_ops->commit_write (fp, page, page_offset, + page_offset + chunk + skip); + } + unlock_page (page); + reiserfs_put_page (page); + buffer_pos += chunk; + file_pos += chunk; + skip = 0; + if (err || buffer_size == 0 || !buffer) + break; + } + + /* We can't mark the inode dirty if it's not hashed. This is the case + * when we're inheriting the default ACL. If we dirty it, the inode + * gets marked dirty, but won't (ever) make it onto the dirty list until + * it's synced explicitly to clear I_DIRTY. This is bad. */ + if (!hlist_unhashed(&inode->i_hash)) { + inode->i_ctime = CURRENT_TIME_SEC; + mark_inode_dirty (inode); + } + +out_filp: + up (&xinode->i_sem); + fput(fp); + +out: + return err; +} + +/* + * inode->i_sem: down + */ +int +reiserfs_xattr_get (const struct inode *inode, const char *name, void *buffer, + size_t buffer_size) +{ + ssize_t err = 0; + struct file *fp; + size_t isize; + size_t file_pos = 0; + size_t buffer_pos = 0; + struct page *page; + struct inode *xinode; + __u32 hash = 0; + + if (name == NULL) + return -EINVAL; + + /* We can't have xattrs attached to v1 items since they don't have + * generation numbers */ + if (get_inode_sd_version (inode) == STAT_DATA_V1) + return -EOPNOTSUPP; + + fp = open_xa_file (inode, name, FL_READONLY); + if (IS_ERR (fp)) { + err = PTR_ERR (fp); + goto out; + } + + xinode = fp->f_dentry->d_inode; + isize = xinode->i_size; + REISERFS_I(inode)->i_flags |= i_has_xattr_dir; + + /* Just return the size needed */ + if (buffer == NULL) { + err = isize - sizeof (struct reiserfs_xattr_header); + goto out_dput; + } + + if (buffer_size < isize - sizeof (struct reiserfs_xattr_header)) { + err = -ERANGE; + goto out_dput; + } + + while (file_pos < isize) { + size_t chunk; + char *data; + size_t skip = 0; + if (isize - file_pos > PAGE_CACHE_SIZE) + chunk = PAGE_CACHE_SIZE; + else + chunk = isize - file_pos; + + page = reiserfs_get_page (xinode, file_pos >> PAGE_CACHE_SHIFT); + if (IS_ERR (page)) { + err = PTR_ERR (page); + goto out_dput; + } + + lock_page (page); + data = page_address (page); + if (file_pos == 0) { + struct reiserfs_xattr_header *rxh = + (struct reiserfs_xattr_header *)data; + skip = file_pos = sizeof (struct reiserfs_xattr_header); + chunk -= skip; + /* Magic doesn't match up.. */ + if (rxh->h_magic != cpu_to_le32 (REISERFS_XATTR_MAGIC)) { + unlock_page (page); + reiserfs_put_page (page); + reiserfs_warning (inode->i_sb, "Invalid magic for xattr (%s) " + "associated with %k", name, + INODE_PKEY (inode)); + err = -EIO; + goto out_dput; + } + hash = le32_to_cpu (rxh->h_hash); + } + memcpy (buffer + buffer_pos, data + skip, chunk); + unlock_page (page); + reiserfs_put_page (page); + file_pos += chunk; + buffer_pos += chunk; + skip = 0; + } + err = isize - sizeof (struct reiserfs_xattr_header); + + if (xattr_hash (buffer, isize - sizeof (struct reiserfs_xattr_header)) != hash) { + reiserfs_warning (inode->i_sb, "Invalid hash for xattr (%s) associated " + "with %k", name, INODE_PKEY (inode)); + err = -EIO; + } + +out_dput: + fput(fp); + +out: + return err; +} + +static int +__reiserfs_xattr_del (struct dentry *xadir, const char *name, int namelen) +{ + struct dentry *dentry; + struct inode *dir = xadir->d_inode; + int err = 0; + + dentry = lookup_one_len (name, xadir, namelen); + if (IS_ERR (dentry)) { + err = PTR_ERR (dentry); + goto out; + } else if (!dentry->d_inode) { + err = -ENODATA; + goto out_file; + } + + /* Skip directories.. */ + if (S_ISDIR (dentry->d_inode->i_mode)) + goto out_file; + + if (!is_reiserfs_priv_object (dentry->d_inode)) { + reiserfs_warning (dir->i_sb, "OID %08x [%.*s/%.*s] doesn't have " + "priv flag set [parent is %sset].", + le32_to_cpu (INODE_PKEY (dentry->d_inode)->k_objectid), + xadir->d_name.len, xadir->d_name.name, namelen, name, + is_reiserfs_priv_object (xadir->d_inode) ? "" : "not "); + dput (dentry); + return -EIO; + } + + err = dir->i_op->unlink (dir, dentry); + if (!err) + d_delete (dentry); + +out_file: + dput (dentry); + +out: + return err; +} + + +int +reiserfs_xattr_del (struct inode *inode, const char *name) +{ + struct dentry *dir; + int err; + + if (IS_RDONLY (inode)) + return -EROFS; + + dir = open_xa_dir (inode, FL_READONLY); + if (IS_ERR (dir)) { + err = PTR_ERR (dir); + goto out; + } + + err = __reiserfs_xattr_del (dir, name, strlen (name)); + dput (dir); + + if (!err) { + inode->i_ctime = CURRENT_TIME_SEC; + mark_inode_dirty (inode); + } + +out: + return err; +} + +/* The following are side effects of other operations that aren't explicitly + * modifying extended attributes. This includes operations such as permissions + * or ownership changes, object deletions, etc. */ + +static int +reiserfs_delete_xattrs_filler (void *buf, const char *name, int namelen, + loff_t offset, ino_t ino, unsigned int d_type) +{ + struct dentry *xadir = (struct dentry *)buf; + + return __reiserfs_xattr_del (xadir, name, namelen); + +} + +/* This is called w/ inode->i_sem downed */ +int +reiserfs_delete_xattrs (struct inode *inode) +{ + struct file *fp; + struct dentry *dir, *root; + int err = 0; + + /* Skip out, an xattr has no xattrs associated with it */ + if (is_reiserfs_priv_object (inode) || + get_inode_sd_version (inode) == STAT_DATA_V1 || + !reiserfs_xattrs(inode->i_sb)) + { + return 0; + } + reiserfs_read_lock_xattrs (inode->i_sb); + dir = open_xa_dir (inode, FL_READONLY); + reiserfs_read_unlock_xattrs (inode->i_sb); + if (IS_ERR (dir)) { + err = PTR_ERR (dir); + goto out; + } else if (!dir->d_inode) { + dput (dir); + return 0; + } + + fp = dentry_open (dir, NULL, O_RDWR); + if (IS_ERR (fp)) { + err = PTR_ERR (fp); + /* dentry_open dputs the dentry if it fails */ + goto out; + } + + lock_kernel (); + err = xattr_readdir (fp, reiserfs_delete_xattrs_filler, dir); + if (err) { + unlock_kernel (); + goto out_dir; + } + + /* Leftovers besides . and .. -- that's not good. */ + if (dir->d_inode->i_nlink <= 2) { + root = get_xa_root (inode->i_sb); + reiserfs_write_lock_xattrs (inode->i_sb); + err = vfs_rmdir (root->d_inode, dir); + reiserfs_write_unlock_xattrs (inode->i_sb); + dput (root); + } else { + reiserfs_warning (inode->i_sb, + "Couldn't remove all entries in directory"); + } + unlock_kernel (); + +out_dir: + fput(fp); + +out: + if (!err) + REISERFS_I(inode)->i_flags = REISERFS_I(inode)->i_flags & ~i_has_xattr_dir; + return err; +} + +struct reiserfs_chown_buf { + struct inode *inode; + struct dentry *xadir; + struct iattr *attrs; +}; + +/* XXX: If there is a better way to do this, I'd love to hear about it */ +static int +reiserfs_chown_xattrs_filler (void *buf, const char *name, int namelen, + loff_t offset, ino_t ino, unsigned int d_type) +{ + struct reiserfs_chown_buf *chown_buf = (struct reiserfs_chown_buf *)buf; + struct dentry *xafile, *xadir = chown_buf->xadir; + struct iattr *attrs = chown_buf->attrs; + int err = 0; + + xafile = lookup_one_len (name, xadir, namelen); + if (IS_ERR (xafile)) + return PTR_ERR (xafile); + else if (!xafile->d_inode) { + dput (xafile); + return -ENODATA; + } + + if (!S_ISDIR (xafile->d_inode->i_mode)) + err = notify_change (xafile, attrs); + dput (xafile); + + return err; +} + +int +reiserfs_chown_xattrs (struct inode *inode, struct iattr *attrs) +{ + struct file *fp; + struct dentry *dir; + int err = 0; + struct reiserfs_chown_buf buf; + unsigned int ia_valid = attrs->ia_valid; + + /* Skip out, an xattr has no xattrs associated with it */ + if (is_reiserfs_priv_object (inode) || + get_inode_sd_version (inode) == STAT_DATA_V1 || + !reiserfs_xattrs(inode->i_sb)) + { + return 0; + } + reiserfs_read_lock_xattrs (inode->i_sb); + dir = open_xa_dir (inode, FL_READONLY); + reiserfs_read_unlock_xattrs (inode->i_sb); + if (IS_ERR (dir)) { + if (PTR_ERR (dir) != -ENODATA) + err = PTR_ERR (dir); + goto out; + } else if (!dir->d_inode) { + dput (dir); + goto out; + } + + fp = dentry_open (dir, NULL, O_RDWR); + if (IS_ERR (fp)) { + err = PTR_ERR (fp); + /* dentry_open dputs the dentry if it fails */ + goto out; + } + + lock_kernel (); + + attrs->ia_valid &= (ATTR_UID | ATTR_GID | ATTR_CTIME); + buf.xadir = dir; + buf.attrs = attrs; + buf.inode = inode; + + err = xattr_readdir (fp, reiserfs_chown_xattrs_filler, &buf); + if (err) { + unlock_kernel (); + goto out_dir; + } + + err = notify_change (dir, attrs); + unlock_kernel (); + +out_dir: + fput(fp); + +out: + attrs->ia_valid = ia_valid; + return err; +} + + +/* Actual operations that are exported to VFS-land */ + +/* + * Inode operation getxattr() + * Preliminary locking: we down dentry->d_inode->i_sem + */ +ssize_t +reiserfs_getxattr (struct dentry *dentry, const char *name, void *buffer, + size_t size) +{ + struct reiserfs_xattr_handler *xah = find_xattr_handler_prefix (name); + int err; + + if (!xah || !reiserfs_xattrs(dentry->d_sb) || + get_inode_sd_version (dentry->d_inode) == STAT_DATA_V1) + return -EOPNOTSUPP; + + reiserfs_read_lock_xattr_i (dentry->d_inode); + reiserfs_read_lock_xattrs (dentry->d_sb); + err = xah->get (dentry->d_inode, name, buffer, size); + reiserfs_read_unlock_xattrs (dentry->d_sb); + reiserfs_read_unlock_xattr_i (dentry->d_inode); + return err; +} + + +/* + * Inode operation setxattr() + * + * dentry->d_inode->i_sem down + */ +int +reiserfs_setxattr (struct dentry *dentry, const char *name, const void *value, + size_t size, int flags) +{ + struct reiserfs_xattr_handler *xah = find_xattr_handler_prefix (name); + int err; + int lock; + + if (!xah || !reiserfs_xattrs(dentry->d_sb) || + get_inode_sd_version (dentry->d_inode) == STAT_DATA_V1) + return -EOPNOTSUPP; + + if (IS_RDONLY (dentry->d_inode)) + return -EROFS; + + if (IS_IMMUTABLE (dentry->d_inode) || IS_APPEND (dentry->d_inode)) + return -EROFS; + + reiserfs_write_lock_xattr_i (dentry->d_inode); + lock = !has_xattr_dir (dentry->d_inode); + if (lock) + reiserfs_write_lock_xattrs (dentry->d_sb); + else + reiserfs_read_lock_xattrs (dentry->d_sb); + err = xah->set (dentry->d_inode, name, value, size, flags); + if (lock) + reiserfs_write_unlock_xattrs (dentry->d_sb); + else + reiserfs_read_unlock_xattrs (dentry->d_sb); + reiserfs_write_unlock_xattr_i (dentry->d_inode); + return err; +} + +/* + * Inode operation removexattr() + * + * dentry->d_inode->i_sem down + */ +int +reiserfs_removexattr (struct dentry *dentry, const char *name) +{ + int err; + struct reiserfs_xattr_handler *xah = find_xattr_handler_prefix (name); + + if (!xah || !reiserfs_xattrs(dentry->d_sb) || + get_inode_sd_version (dentry->d_inode) == STAT_DATA_V1) + return -EOPNOTSUPP; + + if (IS_RDONLY (dentry->d_inode)) + return -EROFS; + + if (IS_IMMUTABLE (dentry->d_inode) || IS_APPEND (dentry->d_inode)) + return -EPERM; + + reiserfs_write_lock_xattr_i (dentry->d_inode); + reiserfs_read_lock_xattrs (dentry->d_sb); + + /* Deletion pre-operation */ + if (xah->del) { + err = xah->del (dentry->d_inode, name); + if (err) + goto out; + } + + err = reiserfs_xattr_del (dentry->d_inode, name); + + dentry->d_inode->i_ctime = CURRENT_TIME_SEC; + mark_inode_dirty (dentry->d_inode); + +out: + reiserfs_read_unlock_xattrs (dentry->d_sb); + reiserfs_write_unlock_xattr_i (dentry->d_inode); + return err; +} + + +/* This is what filldir will use: + * r_pos will always contain the amount of space required for the entire + * list. If r_pos becomes larger than r_size, we need more space and we + * return an error indicating this. If r_pos is less than r_size, then we've + * filled the buffer successfully and we return success */ +struct reiserfs_listxattr_buf { + int r_pos; + int r_size; + char *r_buf; + struct inode *r_inode; +}; + +static int +reiserfs_listxattr_filler (void *buf, const char *name, int namelen, + loff_t offset, ino_t ino, unsigned int d_type) +{ + struct reiserfs_listxattr_buf *b = (struct reiserfs_listxattr_buf *)buf; + int len = 0; + if (name[0] != '.' || (namelen != 1 && (name[1] != '.' || namelen != 2))) { + struct reiserfs_xattr_handler *xah = find_xattr_handler_prefix (name); + if (!xah) return 0; /* Unsupported xattr name, skip it */ + + /* We call ->list() twice because the operation isn't required to just + * return the name back - we want to make sure we have enough space */ + len += xah->list (b->r_inode, name, namelen, NULL); + + if (len) { + if (b->r_pos + len + 1 <= b->r_size) { + char *p = b->r_buf + b->r_pos; + p += xah->list (b->r_inode, name, namelen, p); + *p++ = '\0'; + } + b->r_pos += len + 1; + } + } + + return 0; +} +/* + * Inode operation listxattr() + * + * Preliminary locking: we down dentry->d_inode->i_sem + */ +ssize_t +reiserfs_listxattr (struct dentry *dentry, char *buffer, size_t size) +{ + struct file *fp; + struct dentry *dir; + int err = 0; + struct reiserfs_listxattr_buf buf; + + if (!dentry->d_inode) + return -EINVAL; + + if (!reiserfs_xattrs(dentry->d_sb) || + get_inode_sd_version (dentry->d_inode) == STAT_DATA_V1) + return -EOPNOTSUPP; + + reiserfs_read_lock_xattr_i (dentry->d_inode); + reiserfs_read_lock_xattrs (dentry->d_sb); + dir = open_xa_dir (dentry->d_inode, FL_READONLY); + reiserfs_read_unlock_xattrs (dentry->d_sb); + if (IS_ERR (dir)) { + err = PTR_ERR (dir); + if (err == -ENODATA) + err = 0; /* Not an error if there aren't any xattrs */ + goto out; + } + + fp = dentry_open (dir, NULL, O_RDWR); + if (IS_ERR (fp)) { + err = PTR_ERR (fp); + /* dentry_open dputs the dentry if it fails */ + goto out; + } + + buf.r_buf = buffer; + buf.r_size = buffer ? size : 0; + buf.r_pos = 0; + buf.r_inode = dentry->d_inode; + + REISERFS_I(dentry->d_inode)->i_flags |= i_has_xattr_dir; + + err = xattr_readdir (fp, reiserfs_listxattr_filler, &buf); + if (err) + goto out_dir; + + if (buf.r_pos > buf.r_size && buffer != NULL) + err = -ERANGE; + else + err = buf.r_pos; + +out_dir: + fput(fp); + +out: + reiserfs_read_unlock_xattr_i (dentry->d_inode); + return err; +} + +/* This is the implementation for the xattr plugin infrastructure */ +static struct list_head xattr_handlers = LIST_HEAD_INIT (xattr_handlers); +static DEFINE_RWLOCK(handler_lock); + +static struct reiserfs_xattr_handler * +find_xattr_handler_prefix (const char *prefix) +{ + struct reiserfs_xattr_handler *xah = NULL; + struct list_head *p; + + read_lock (&handler_lock); + list_for_each (p, &xattr_handlers) { + xah = list_entry (p, struct reiserfs_xattr_handler, handlers); + if (strncmp (xah->prefix, prefix, strlen (xah->prefix)) == 0) + break; + xah = NULL; + } + + read_unlock (&handler_lock); + return xah; +} + +static void +__unregister_handlers (void) +{ + struct reiserfs_xattr_handler *xah; + struct list_head *p, *tmp; + + list_for_each_safe (p, tmp, &xattr_handlers) { + xah = list_entry (p, struct reiserfs_xattr_handler, handlers); + if (xah->exit) + xah->exit(); + + list_del_init (p); + } + INIT_LIST_HEAD (&xattr_handlers); +} + +int __init +reiserfs_xattr_register_handlers (void) +{ + int err = 0; + struct reiserfs_xattr_handler *xah; + struct list_head *p; + + write_lock (&handler_lock); + + /* If we're already initialized, nothing to do */ + if (!list_empty (&xattr_handlers)) { + write_unlock (&handler_lock); + return 0; + } + + /* Add the handlers */ + list_add_tail (&user_handler.handlers, &xattr_handlers); + list_add_tail (&trusted_handler.handlers, &xattr_handlers); +#ifdef CONFIG_REISERFS_FS_SECURITY + list_add_tail (&security_handler.handlers, &xattr_handlers); +#endif +#ifdef CONFIG_REISERFS_FS_POSIX_ACL + list_add_tail (&posix_acl_access_handler.handlers, &xattr_handlers); + list_add_tail (&posix_acl_default_handler.handlers, &xattr_handlers); +#endif + + /* Run initializers, if available */ + list_for_each (p, &xattr_handlers) { + xah = list_entry (p, struct reiserfs_xattr_handler, handlers); + if (xah->init) { + err = xah->init (); + if (err) { + list_del_init (p); + break; + } + } + } + + /* Clean up other handlers, if any failed */ + if (err) + __unregister_handlers (); + + write_unlock (&handler_lock); + return err; +} + +void +reiserfs_xattr_unregister_handlers (void) +{ + write_lock (&handler_lock); + __unregister_handlers (); + write_unlock (&handler_lock); +} + +/* This will catch lookups from the fs root to .reiserfs_priv */ +static int +xattr_lookup_poison (struct dentry *dentry, struct qstr *q1, struct qstr *name) +{ + struct dentry *priv_root = REISERFS_SB(dentry->d_sb)->priv_root; + if (name->len == priv_root->d_name.len && + name->hash == priv_root->d_name.hash && + !memcmp (name->name, priv_root->d_name.name, name->len)) { + return -ENOENT; + } else if (q1->len == name->len && + !memcmp(q1->name, name->name, name->len)) + return 0; + return 1; +} + +static struct dentry_operations xattr_lookup_poison_ops = { + .d_compare = xattr_lookup_poison, +}; + + +/* We need to take a copy of the mount flags since things like + * MS_RDONLY don't get set until *after* we're called. + * mount_flags != mount_options */ +int +reiserfs_xattr_init (struct super_block *s, int mount_flags) +{ + int err = 0; + + /* We need generation numbers to ensure that the oid mapping is correct + * v3.5 filesystems don't have them. */ + if (!old_format_only (s)) { + set_bit (REISERFS_XATTRS, &(REISERFS_SB(s)->s_mount_opt)); + } else if (reiserfs_xattrs_optional (s)) { + /* Old format filesystem, but optional xattrs have been enabled + * at mount time. Error out. */ + reiserfs_warning (s, "xattrs/ACLs not supported on pre v3.6 " + "format filesystem. Failing mount."); + err = -EOPNOTSUPP; + goto error; + } else { + /* Old format filesystem, but no optional xattrs have been enabled. This + * means we silently disable xattrs on the filesystem. */ + clear_bit (REISERFS_XATTRS, &(REISERFS_SB(s)->s_mount_opt)); + } + + /* If we don't have the privroot located yet - go find it */ + if (reiserfs_xattrs (s) && !REISERFS_SB(s)->priv_root) { + struct dentry *dentry; + dentry = lookup_one_len (PRIVROOT_NAME, s->s_root, + strlen (PRIVROOT_NAME)); + if (!IS_ERR (dentry)) { + if (!(mount_flags & MS_RDONLY) && !dentry->d_inode) { + struct inode *inode = dentry->d_parent->d_inode; + down (&inode->i_sem); + err = inode->i_op->mkdir (inode, dentry, 0700); + up (&inode->i_sem); + if (err) { + dput (dentry); + dentry = NULL; + } + + if (dentry && dentry->d_inode) + reiserfs_warning (s, "Created %s on %s - reserved for " + "xattr storage.", PRIVROOT_NAME, + reiserfs_bdevname (inode->i_sb)); + } else if (!dentry->d_inode) { + dput (dentry); + dentry = NULL; + } + } else + err = PTR_ERR (dentry); + + if (!err && dentry) { + s->s_root->d_op = &xattr_lookup_poison_ops; + reiserfs_mark_inode_private (dentry->d_inode); + REISERFS_SB(s)->priv_root = dentry; + } else if (!(mount_flags & MS_RDONLY)) { /* xattrs are unavailable */ + /* If we're read-only it just means that the dir hasn't been + * created. Not an error -- just no xattrs on the fs. We'll + * check again if we go read-write */ + reiserfs_warning (s, "xattrs/ACLs enabled and couldn't " + "find/create .reiserfs_priv. Failing mount."); + err = -EOPNOTSUPP; + } + } + +error: + /* This is only nonzero if there was an error initializing the xattr + * directory or if there is a condition where we don't support them. */ + if (err) { + clear_bit (REISERFS_XATTRS, &(REISERFS_SB(s)->s_mount_opt)); + clear_bit (REISERFS_XATTRS_USER, &(REISERFS_SB(s)->s_mount_opt)); + clear_bit (REISERFS_POSIXACL, &(REISERFS_SB(s)->s_mount_opt)); + } + + /* The super_block MS_POSIXACL must mirror the (no)acl mount option. */ + s->s_flags = s->s_flags & ~MS_POSIXACL; + if (reiserfs_posixacl (s)) + s->s_flags |= MS_POSIXACL; + + return err; +} + +static int +__reiserfs_permission (struct inode *inode, int mask, struct nameidata *nd, + int need_lock) +{ + umode_t mode = inode->i_mode; + + if (mask & MAY_WRITE) { + /* + * Nobody gets write access to a read-only fs. + */ + if (IS_RDONLY(inode) && + (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) + return -EROFS; + + /* + * Nobody gets write access to an immutable file. + */ + if (IS_IMMUTABLE(inode)) + return -EACCES; + } + + /* We don't do permission checks on the internal objects. + * Permissions are determined by the "owning" object. */ + if (is_reiserfs_priv_object (inode)) + return 0; + + if (current->fsuid == inode->i_uid) { + mode >>= 6; +#ifdef CONFIG_REISERFS_FS_POSIX_ACL + } else if (reiserfs_posixacl(inode->i_sb) && + get_inode_sd_version (inode) != STAT_DATA_V1) { + struct posix_acl *acl; + + /* ACL can't contain additional permissions if + the ACL_MASK entry is 0 */ + if (!(mode & S_IRWXG)) + goto check_groups; + + if (need_lock) { + reiserfs_read_lock_xattr_i (inode); + reiserfs_read_lock_xattrs (inode->i_sb); + } + acl = reiserfs_get_acl (inode, ACL_TYPE_ACCESS); + if (need_lock) { + reiserfs_read_unlock_xattrs (inode->i_sb); + reiserfs_read_unlock_xattr_i (inode); + } + if (IS_ERR (acl)) { + if (PTR_ERR (acl) == -ENODATA) + goto check_groups; + return PTR_ERR (acl); + } + + if (acl) { + int err = posix_acl_permission (inode, acl, mask); + posix_acl_release (acl); + if (err == -EACCES) { + goto check_capabilities; + } + return err; + } else { + goto check_groups; + } +#endif + } else { +check_groups: + if (in_group_p(inode->i_gid)) + mode >>= 3; + } + + /* + * If the DACs are ok we don't need any capability check. + */ + if (((mode & mask & (MAY_READ|MAY_WRITE|MAY_EXEC)) == mask)) + return 0; + +check_capabilities: + /* + * Read/write DACs are always overridable. + * Executable DACs are overridable if at least one exec bit is set. + */ + if (!(mask & MAY_EXEC) || + (inode->i_mode & S_IXUGO) || S_ISDIR(inode->i_mode)) + if (capable(CAP_DAC_OVERRIDE)) + return 0; + + /* + * Searching includes executable on directories, else just read. + */ + if (mask == MAY_READ || (S_ISDIR(inode->i_mode) && !(mask & MAY_WRITE))) + if (capable(CAP_DAC_READ_SEARCH)) + return 0; + + return -EACCES; +} + +int +reiserfs_permission (struct inode *inode, int mask, struct nameidata *nd) +{ + return __reiserfs_permission (inode, mask, nd, 1); +} + +int +reiserfs_permission_locked (struct inode *inode, int mask, struct nameidata *nd) +{ + return __reiserfs_permission (inode, mask, nd, 0); +} |