/* * 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. * * Locking works like so: * Directory components (xattr root, xattr dir) are protectd by their i_mutex. * The xattrs themselves are protected by the xattr_sem. */ #include <linux/reiserfs_fs.h> #include <linux/capability.h> #include <linux/dcache.h> #include <linux/namei.h> #include <linux/errno.h> #include <linux/gfp.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 <asm/uaccess.h> #include <net/checksum.h> #include <linux/stat.h> #include <linux/quotaops.h> #include <linux/security.h> #define PRIVROOT_NAME ".reiserfs_priv" #define XAROOT_NAME "xattrs" /* Helpers for inode ops. We do this so that we don't have all the VFS * overhead and also for proper i_mutex annotation. * dir->i_mutex must be held for all of them. */ #ifdef CONFIG_REISERFS_FS_XATTR static int xattr_create(struct inode *dir, struct dentry *dentry, int mode) { BUG_ON(!mutex_is_locked(&dir->i_mutex)); return dir->i_op->create(dir, dentry, mode, NULL); } #endif static int xattr_mkdir(struct inode *dir, struct dentry *dentry, int mode) { BUG_ON(!mutex_is_locked(&dir->i_mutex)); return dir->i_op->mkdir(dir, dentry, mode); } /* We use I_MUTEX_CHILD here to silence lockdep. It's safe because xattr * mutation ops aren't called during rename or splace, which are the * only other users of I_MUTEX_CHILD. It violates the ordering, but that's * better than allocating another subclass just for this code. */ static int xattr_unlink(struct inode *dir, struct dentry *dentry) { int error; BUG_ON(!mutex_is_locked(&dir->i_mutex)); reiserfs_mutex_lock_nested_safe(&dentry->d_inode->i_mutex, I_MUTEX_CHILD, dir->i_sb); error = dir->i_op->unlink(dir, dentry); mutex_unlock(&dentry->d_inode->i_mutex); if (!error) d_delete(dentry); return error; } static int xattr_rmdir(struct inode *dir, struct dentry *dentry) { int error; BUG_ON(!mutex_is_locked(&dir->i_mutex)); reiserfs_mutex_lock_nested_safe(&dentry->d_inode->i_mutex, I_MUTEX_CHILD, dir->i_sb); dentry_unhash(dentry); error = dir->i_op->rmdir(dir, dentry); if (!error) dentry->d_inode->i_flags |= S_DEAD; mutex_unlock(&dentry->d_inode->i_mutex); if (!error) d_delete(dentry); dput(dentry); return error; } #define xattr_may_create(flags) (!flags || flags & XATTR_CREATE) static struct dentry *open_xa_root(struct super_block *sb, int flags) { struct dentry *privroot = REISERFS_SB(sb)->priv_root; struct dentry *xaroot; if (!privroot->d_inode) return ERR_PTR(-ENODATA); mutex_lock_nested(&privroot->d_inode->i_mutex, I_MUTEX_XATTR); xaroot = dget(REISERFS_SB(sb)->xattr_root); if (!xaroot) xaroot = ERR_PTR(-ENODATA); else if (!xaroot->d_inode) { int err = -ENODATA; if (xattr_may_create(flags)) err = xattr_mkdir(privroot->d_inode, xaroot, 0700); if (err) { dput(xaroot); xaroot = ERR_PTR(err); } } mutex_unlock(&privroot->d_inode->i_mutex); return xaroot; } static struct dentry *open_xa_dir(const struct inode *inode, int flags) { struct dentry *xaroot, *xadir; char namebuf[17]; xaroot = open_xa_root(inode->i_sb, flags); if (IS_ERR(xaroot)) return xaroot; snprintf(namebuf, sizeof(namebuf), "%X.%X", le32_to_cpu(INODE_PKEY(inode)->k_objectid), inode->i_generation); mutex_lock_nested(&xaroot->d_inode->i_mutex, I_MUTEX_XATTR); xadir = lookup_one_len(namebuf, xaroot, strlen(namebuf)); if (!IS_ERR(xadir) && !xadir->d_inode) { int err = -ENODATA; if (xattr_may_create(flags)) err = xattr_mkdir(xaroot->d_inode, xadir, 0700); if (err) { dput(xadir); xadir = ERR_PTR(err); } } mutex_unlock(&xaroot->d_inode->i_mutex); dput(xaroot); return xadir; } /* 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. */ struct reiserfs_dentry_buf { struct dentry *xadir; int count; struct dentry *dentries[8]; }; static int fill_with_dentries(void *buf, const char *name, int namelen, loff_t offset, u64 ino, unsigned int d_type) { struct reiserfs_dentry_buf *dbuf = buf; struct dentry *dentry; WARN_ON_ONCE(!mutex_is_locked(&dbuf->xadir->d_inode->i_mutex)); if (dbuf->count == ARRAY_SIZE(dbuf->dentries)) return -ENOSPC; if (name[0] == '.' && (name[1] == '\0' || (name[1] == '.' && name[2] == '\0'))) return 0; dentry = lookup_one_len(name, dbuf->xadir, namelen); if (IS_ERR(dentry)) { return PTR_ERR(dentry); } else if (!dentry->d_inode) { /* A directory entry exists, but no file? */ reiserfs_error(dentry->d_sb, "xattr-20003", "Corrupted directory: xattr %s listed but " "not found for file %s.\n", dentry->d_name.name, dbuf->xadir->d_name.name); dput(dentry); return -EIO; } dbuf->dentries[dbuf->count++] = dentry; return 0; } static void cleanup_dentry_buf(struct reiserfs_dentry_buf *buf) { int i; for (i = 0; i < buf->count; i++) if (buf->dentries[i]) dput(buf->dentries[i]); } static int reiserfs_for_each_xattr(struct inode *inode, int (*action)(struct dentry *, void *), void *data) { struct dentry *dir; int i, err = 0; loff_t pos = 0; struct reiserfs_dentry_buf buf = { .count = 0, }; /* Skip out, an xattr has no xattrs associated with it */ if (IS_PRIVATE(inode) || get_inode_sd_version(inode) == STAT_DATA_V1) return 0; reiserfs_write_unlock(inode->i_sb); dir = open_xa_dir(inode, XATTR_REPLACE); if (IS_ERR(dir)) { err = PTR_ERR(dir); reiserfs_write_lock(inode->i_sb); goto out; } else if (!dir->d_inode) { err = 0; reiserfs_write_lock(inode->i_sb); goto out_dir; } mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_XATTR); reiserfs_write_lock(inode->i_sb); buf.xadir = dir; err = reiserfs_readdir_dentry(dir, &buf, fill_with_dentries, &pos); while ((err == 0 || err == -ENOSPC) && buf.count) { err = 0; for (i = 0; i < buf.count && buf.dentries[i]; i++) { int lerr = 0; struct dentry *dentry = buf.dentries[i]; if (err == 0 && !S_ISDIR(dentry->d_inode->i_mode)) lerr = action(dentry, data); dput(dentry); buf.dentries[i] = NULL; err = lerr ?: err; } buf.count = 0; if (!err) err = reiserfs_readdir_dentry(dir, &buf, fill_with_dentries, &pos); } mutex_unlock(&dir->d_inode->i_mutex); /* Clean up after a failed readdir */ cleanup_dentry_buf(&buf); if (!err) { /* We start a transaction here to avoid a ABBA situation * between the xattr root's i_mutex and the journal lock. * This doesn't incur much additional overhead since the * new transaction will just nest inside the * outer transaction. */ int blocks = JOURNAL_PER_BALANCE_CNT * 2 + 2 + 4 * REISERFS_QUOTA_TRANS_BLOCKS(inode->i_sb); struct reiserfs_transaction_handle th; err = journal_begin(&th, inode->i_sb, blocks); if (!err) { int jerror; reiserfs_mutex_lock_nested_safe( &dir->d_parent->d_inode->i_mutex, I_MUTEX_XATTR, inode->i_sb); err = action(dir, data); jerror = journal_end(&th, inode->i_sb, blocks); mutex_unlock(&dir->d_parent->d_inode->i_mutex); err = jerror ?: err; } } out_dir: dput(dir); out: /* -ENODATA isn't an error */ if (err == -ENODATA) err = 0; return err; } static int delete_one_xattr(struct dentry *dentry, void *data) { struct inode *dir = dentry->d_parent->d_inode; /* This is the xattr dir, handle specially. */ if (S_ISDIR(dentry->d_inode->i_mode)) return xattr_rmdir(dir, dentry); return xattr_unlink(dir, dentry); } static int chown_one_xattr(struct dentry *dentry, void *data) { struct iattr *attrs = data; return reiserfs_setattr(dentry, attrs); } /* No i_mutex, but the inode is unconnected. */ int reiserfs_delete_xattrs(struct inode *inode) { int err = reiserfs_for_each_xattr(inode, delete_one_xattr, NULL); if (err) reiserfs_warning(inode->i_sb, "jdm-20004", "Couldn't delete all xattrs (%d)\n", err); return err; } /* inode->i_mutex: down */ int reiserfs_chown_xattrs(struct inode *inode, struct iattr *attrs) { int err = reiserfs_for_each_xattr(inode, chown_one_xattr, attrs); if (err) reiserfs_warning(inode->i_sb, "jdm-20007", "Couldn't chown all xattrs (%d)\n", err); return err; } #ifdef CONFIG_REISERFS_FS_XATTR /* 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 *xattr_lookup(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_CAST(xadir); mutex_lock_nested(&xadir->d_inode->i_mutex, I_MUTEX_XATTR); xafile = lookup_one_len(name, xadir, strlen(name)); if (IS_ERR(xafile)) { err = PTR_ERR(xafile); goto out; } if (xafile->d_inode && (flags & XATTR_CREATE)) err = -EEXIST; if (!xafile->d_inode) { err = -ENODATA; if (xattr_may_create(flags)) err = xattr_create(xadir->d_inode, xafile, 0700|S_IFREG); } if (err) dput(xafile); out: mutex_unlock(&xadir->d_inode->i_mutex); dput(xadir); if (err) return ERR_PTR(err); return xafile; } /* 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, size_t 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_set_gfp_mask(mapping, GFP_NOFS); page = read_mapping_page(mapping, n >> PAGE_CACHE_SHIFT, NULL); if (!IS_ERR(page)) { kmap(page); 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); } int reiserfs_commit_write(struct file *f, struct page *page, unsigned from, unsigned to); int reiserfs_prepare_write(struct file *f, struct page *page, unsigned from, unsigned to); static void update_ctime(struct inode *inode) { struct timespec now = current_fs_time(inode->i_sb); if (hlist_unhashed(&inode->i_hash) || !inode->i_nlink || timespec_equal(&inode->i_ctime, &now)) return; inode->i_ctime = CURRENT_TIME_SEC; mark_inode_dirty(inode); } static int lookup_and_delete_xattr(struct inode *inode, const char *name) { int err = 0; struct dentry *dentry, *xadir; xadir = open_xa_dir(inode, XATTR_REPLACE); if (IS_ERR(xadir)) return PTR_ERR(xadir); mutex_lock_nested(&xadir->d_inode->i_mutex, I_MUTEX_XATTR); dentry = lookup_one_len(name, xadir, strlen(name)); if (IS_ERR(dentry)) { err = PTR_ERR(dentry); goto out_dput; } if (dentry->d_inode) { reiserfs_write_lock(inode->i_sb); err = xattr_unlink(xadir->d_inode, dentry); reiserfs_write_unlock(inode->i_sb); update_ctime(inode); } dput(dentry); out_dput: mutex_unlock(&xadir->d_inode->i_mutex); dput(xadir); return err; } /* Generic extended attribute operations that can be used by xa plugins */ /* * inode->i_mutex: down */ int reiserfs_xattr_set_handle(struct reiserfs_transaction_handle *th, struct inode *inode, const char *name, const void *buffer, size_t buffer_size, int flags) { int err = 0; struct dentry *dentry; struct page *page; char *data; size_t file_pos = 0; size_t buffer_pos = 0; size_t new_size; __u32 xahash = 0; if (get_inode_sd_version(inode) == STAT_DATA_V1) return -EOPNOTSUPP; reiserfs_write_unlock(inode->i_sb); if (!buffer) { err = lookup_and_delete_xattr(inode, name); reiserfs_write_lock(inode->i_sb); return err; } dentry = xattr_lookup(inode, name, flags); if (IS_ERR(dentry)) { reiserfs_write_lock(inode->i_sb); return PTR_ERR(dentry); } down_write(&REISERFS_I(inode)->i_xattr_sem); reiserfs_write_lock(inode->i_sb); xahash = xattr_hash(buffer, buffer_size); 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(dentry->d_inode, file_pos); if (IS_ERR(page)) { err = PTR_ERR(page); goto out_unlock; } 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 = reiserfs_prepare_write(NULL, page, page_offset, page_offset + chunk + skip); if (!err) { if (buffer) memcpy(data + skip, buffer + buffer_pos, chunk); err = reiserfs_commit_write(NULL, 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; } new_size = buffer_size + sizeof(struct reiserfs_xattr_header); if (!err && new_size < i_size_read(dentry->d_inode)) { struct iattr newattrs = { .ia_ctime = current_fs_time(inode->i_sb), .ia_size = buffer_size, .ia_valid = ATTR_SIZE | ATTR_CTIME, }; reiserfs_write_unlock(inode->i_sb); mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_XATTR); down_write(&dentry->d_inode->i_alloc_sem); reiserfs_write_lock(inode->i_sb); err = reiserfs_setattr(dentry, &newattrs); up_write(&dentry->d_inode->i_alloc_sem); mutex_unlock(&dentry->d_inode->i_mutex); } else update_ctime(inode); out_unlock: up_write(&REISERFS_I(inode)->i_xattr_sem); dput(dentry); return err; } /* We need to start a transaction to maintain lock ordering */ int reiserfs_xattr_set(struct inode *inode, const char *name, const void *buffer, size_t buffer_size, int flags) { struct reiserfs_transaction_handle th; int error, error2; size_t jbegin_count = reiserfs_xattr_nblocks(inode, buffer_size); if (!(flags & XATTR_REPLACE)) jbegin_count += reiserfs_xattr_jcreate_nblocks(inode); reiserfs_write_lock(inode->i_sb); error = journal_begin(&th, inode->i_sb, jbegin_count); if (error) { reiserfs_write_unlock(inode->i_sb); return error; } error = reiserfs_xattr_set_handle(&th, inode, name, buffer, buffer_size, flags); error2 = journal_end(&th, inode->i_sb, jbegin_count); if (error == 0) error = error2; reiserfs_write_unlock(inode->i_sb); return error; } /* * inode->i_mutex: down */ int reiserfs_xattr_get(struct inode *inode, const char *name, void *buffer, size_t buffer_size) { ssize_t err = 0; struct dentry *dentry; size_t isize; size_t file_pos = 0; size_t buffer_pos = 0; struct page *page; __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; dentry = xattr_lookup(inode, name, XATTR_REPLACE); if (IS_ERR(dentry)) { err = PTR_ERR(dentry); goto out; } down_read(&REISERFS_I(inode)->i_xattr_sem); isize = i_size_read(dentry->d_inode); /* Just return the size needed */ if (buffer == NULL) { err = isize - sizeof(struct reiserfs_xattr_header); goto out_unlock; } if (buffer_size < isize - sizeof(struct reiserfs_xattr_header)) { err = -ERANGE; goto out_unlock; } 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(dentry->d_inode, file_pos); if (IS_ERR(page)) { err = PTR_ERR(page); goto out_unlock; } 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, "jdm-20001", "Invalid magic for xattr (%s) " "associated with %k", name, INODE_PKEY(inode)); err = -EIO; goto out_unlock; } 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, "jdm-20002", "Invalid hash for xattr (%s) associated " "with %k", name, INODE_PKEY(inode)); err = -EIO; } out_unlock: up_read(&REISERFS_I(inode)->i_xattr_sem); dput(dentry); out: return err; } /* * In order to implement different sets of xattr operations for each xattr * prefix with the generic xattr API, a filesystem should create a * null-terminated array of struct xattr_handler (one for each prefix) and * hang a pointer to it off of the s_xattr field of the superblock. * * The generic_fooxattr() functions will use this list to dispatch xattr * operations to the correct xattr_handler. */ #define for_each_xattr_handler(handlers, handler) \ for ((handler) = *(handlers)++; \ (handler) != NULL; \ (handler) = *(handlers)++) /* This is the implementation for the xattr plugin infrastructure */ static inline struct xattr_handler * find_xattr_handler_prefix(struct xattr_handler **handlers, const char *name) { struct xattr_handler *xah; if (!handlers) return NULL; for_each_xattr_handler(handlers, xah) { if (strncmp(xah->prefix, name, strlen(xah->prefix)) == 0) break; } return xah; } /* * Inode operation getxattr() */ ssize_t reiserfs_getxattr(struct dentry * dentry, const char *name, void *buffer, size_t size) { struct xattr_handler *handler; handler = find_xattr_handler_prefix(dentry->d_sb->s_xattr, name); if (!handler || get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) return -EOPNOTSUPP; return handler->get(dentry, name, buffer, size, handler->flags); } /* * Inode operation setxattr() * * dentry->d_inode->i_mutex down */ int reiserfs_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags) { struct xattr_handler *handler; handler = find_xattr_handler_prefix(dentry->d_sb->s_xattr, name); if (!handler || get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) return -EOPNOTSUPP; return handler->set(dentry, name, value, size, flags, handler->flags); } /* * Inode operation removexattr() * * dentry->d_inode->i_mutex down */ int reiserfs_removexattr(struct dentry *dentry, const char *name) { struct xattr_handler *handler; handler = find_xattr_handler_prefix(dentry->d_sb->s_xattr, name); if (!handler || get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) return -EOPNOTSUPP; return handler->set(dentry, name, NULL, 0, XATTR_REPLACE, handler->flags); } struct listxattr_buf { size_t size; size_t pos; char *buf; struct dentry *dentry; }; static int listxattr_filler(void *buf, const char *name, int namelen, loff_t offset, u64 ino, unsigned int d_type) { struct listxattr_buf *b = (struct listxattr_buf *)buf; size_t size; if (name[0] != '.' || (namelen != 1 && (name[1] != '.' || namelen != 2))) { struct xattr_handler *handler; handler = find_xattr_handler_prefix(b->dentry->d_sb->s_xattr, name); if (!handler) /* Unsupported xattr name */ return 0; if (b->buf) { size = handler->list(b->dentry, b->buf + b->pos, b->size, name, namelen, handler->flags); if (size > b->size) return -ERANGE; } else { size = handler->list(b->dentry, NULL, 0, name, namelen, handler->flags); } b->pos += size; } return 0; } /* * Inode operation listxattr() * * We totally ignore the generic listxattr here because it would be stupid * not to. Since the xattrs are organized in a directory, we can just * readdir to find them. */ ssize_t reiserfs_listxattr(struct dentry * dentry, char *buffer, size_t size) { struct dentry *dir; int err = 0; loff_t pos = 0; struct listxattr_buf buf = { .dentry = dentry, .buf = buffer, .size = buffer ? size : 0, }; if (!dentry->d_inode) return -EINVAL; if (!dentry->d_sb->s_xattr || get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) return -EOPNOTSUPP; dir = open_xa_dir(dentry->d_inode, XATTR_REPLACE); if (IS_ERR(dir)) { err = PTR_ERR(dir); if (err == -ENODATA) err = 0; /* Not an error if there aren't any xattrs */ goto out; } mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_XATTR); err = reiserfs_readdir_dentry(dir, &buf, listxattr_filler, &pos); mutex_unlock(&dir->d_inode->i_mutex); if (!err) err = buf.pos; dput(dir); out: return err; } static int reiserfs_check_acl(struct inode *inode, int mask) { struct posix_acl *acl; int error = -EAGAIN; /* do regular unix permission checks by default */ acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS); if (acl) { if (!IS_ERR(acl)) { error = posix_acl_permission(inode, acl, mask); posix_acl_release(acl); } else if (PTR_ERR(acl) != -ENODATA) error = PTR_ERR(acl); } return error; } static int create_privroot(struct dentry *dentry) { int err; struct inode *inode = dentry->d_parent->d_inode; WARN_ON_ONCE(!mutex_is_locked(&inode->i_mutex)); err = xattr_mkdir(inode, dentry, 0700); if (err || !dentry->d_inode) { reiserfs_warning(dentry->d_sb, "jdm-20006", "xattrs/ACLs enabled and couldn't " "find/create .reiserfs_priv. " "Failing mount."); return -EOPNOTSUPP; } dentry->d_inode->i_flags |= S_PRIVATE; reiserfs_info(dentry->d_sb, "Created %s - reserved for xattr " "storage.\n", PRIVROOT_NAME); return 0; } #else int __init reiserfs_xattr_register_handlers(void) { return 0; } void reiserfs_xattr_unregister_handlers(void) {} static int create_privroot(struct dentry *dentry) { return 0; } #endif /* Actual operations that are exported to VFS-land */ struct xattr_handler *reiserfs_xattr_handlers[] = { #ifdef CONFIG_REISERFS_FS_XATTR &reiserfs_xattr_user_handler, &reiserfs_xattr_trusted_handler, #endif #ifdef CONFIG_REISERFS_FS_SECURITY &reiserfs_xattr_security_handler, #endif #ifdef CONFIG_REISERFS_FS_POSIX_ACL &reiserfs_posix_acl_access_handler, &reiserfs_posix_acl_default_handler, #endif NULL }; static int xattr_mount_check(struct super_block *s) { /* We need generation numbers to ensure that the oid mapping is correct * v3.5 filesystems don't have them. */ if (old_format_only(s)) { if (reiserfs_xattrs_optional(s)) { /* Old format filesystem, but optional xattrs have * been enabled. Error out. */ reiserfs_warning(s, "jdm-2005", "xattrs/ACLs not supported " "on pre-v3.6 format filesystems. " "Failing mount."); return -EOPNOTSUPP; } } return 0; } int reiserfs_permission(struct inode *inode, int mask) { /* * We don't do permission checks on the internal objects. * Permissions are determined by the "owning" object. */ if (IS_PRIVATE(inode)) return 0; #ifdef CONFIG_REISERFS_FS_XATTR /* * Stat data v1 doesn't support ACLs. */ if (get_inode_sd_version(inode) != STAT_DATA_V1) return generic_permission(inode, mask, reiserfs_check_acl); #endif return generic_permission(inode, mask, NULL); } /* 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 (container_of(q1, struct dentry, d_name) == priv_root) return -ENOENT; if (q1->len == name->len && !memcmp(q1->name, name->name, name->len)) return 0; return 1; } static const struct dentry_operations xattr_lookup_poison_ops = { .d_compare = xattr_lookup_poison, }; int reiserfs_lookup_privroot(struct super_block *s) { struct dentry *dentry; int err = 0; /* If we don't have the privroot located yet - go find it */ reiserfs_mutex_lock_safe(&s->s_root->d_inode->i_mutex, s); dentry = lookup_one_len(PRIVROOT_NAME, s->s_root, strlen(PRIVROOT_NAME)); if (!IS_ERR(dentry)) { REISERFS_SB(s)->priv_root = dentry; if (!reiserfs_expose_privroot(s)) s->s_root->d_op = &xattr_lookup_poison_ops; if (dentry->d_inode) dentry->d_inode->i_flags |= S_PRIVATE; } else err = PTR_ERR(dentry); mutex_unlock(&s->s_root->d_inode->i_mutex); return err; } /* 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; struct dentry *privroot = REISERFS_SB(s)->priv_root; err = xattr_mount_check(s); if (err) goto error; if (!privroot->d_inode && !(mount_flags & MS_RDONLY)) { reiserfs_mutex_lock_safe(&s->s_root->d_inode->i_mutex, s); err = create_privroot(REISERFS_SB(s)->priv_root); mutex_unlock(&s->s_root->d_inode->i_mutex); } if (privroot->d_inode) { s->s_xattr = reiserfs_xattr_handlers; reiserfs_mutex_lock_safe(&privroot->d_inode->i_mutex, s); if (!REISERFS_SB(s)->xattr_root) { struct dentry *dentry; dentry = lookup_one_len(XAROOT_NAME, privroot, strlen(XAROOT_NAME)); if (!IS_ERR(dentry)) REISERFS_SB(s)->xattr_root = dentry; else err = PTR_ERR(dentry); } mutex_unlock(&privroot->d_inode->i_mutex); } error: if (err) { 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. */ if (reiserfs_posixacl(s)) s->s_flags |= MS_POSIXACL; else s->s_flags &= ~MS_POSIXACL; return err; }