diff options
Diffstat (limited to 'fs/reiserfs/xattr.c')
| -rw-r--r-- | fs/reiserfs/xattr.c | 1037 |
1 files changed, 1037 insertions, 0 deletions
diff --git a/fs/reiserfs/xattr.c b/fs/reiserfs/xattr.c new file mode 100644 index 000000000..8b2d52443 --- /dev/null +++ b/fs/reiserfs/xattr.c @@ -0,0 +1,1037 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * 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 "reiserfs.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 "xattr.h" +#include "acl.h" +#include <linux/uaccess.h> +#include <net/checksum.h> +#include <linux/stat.h> +#include <linux/quotaops.h> +#include <linux/security.h> +#include <linux/posix_acl_xattr.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(!inode_is_locked(dir)); + return dir->i_op->create(&init_user_ns, dir, dentry, mode, true); +} +#endif + +static int xattr_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) +{ + BUG_ON(!inode_is_locked(dir)); + return dir->i_op->mkdir(&init_user_ns, 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(!inode_is_locked(dir)); + + inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD); + error = dir->i_op->unlink(dir, dentry); + inode_unlock(d_inode(dentry)); + + if (!error) + d_delete(dentry); + return error; +} + +static int xattr_rmdir(struct inode *dir, struct dentry *dentry) +{ + int error; + + BUG_ON(!inode_is_locked(dir)); + + inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD); + error = dir->i_op->rmdir(dir, dentry); + if (!error) + d_inode(dentry)->i_flags |= S_DEAD; + inode_unlock(d_inode(dentry)); + if (!error) + d_delete(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 (d_really_is_negative(privroot)) + return ERR_PTR(-EOPNOTSUPP); + + inode_lock_nested(d_inode(privroot), I_MUTEX_XATTR); + + xaroot = dget(REISERFS_SB(sb)->xattr_root); + if (!xaroot) + xaroot = ERR_PTR(-EOPNOTSUPP); + else if (d_really_is_negative(xaroot)) { + int err = -ENODATA; + + if (xattr_may_create(flags)) + err = xattr_mkdir(d_inode(privroot), xaroot, 0700); + if (err) { + dput(xaroot); + xaroot = ERR_PTR(err); + } + } + + inode_unlock(d_inode(privroot)); + 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); + + inode_lock_nested(d_inode(xaroot), I_MUTEX_XATTR); + + xadir = lookup_one_len(namebuf, xaroot, strlen(namebuf)); + if (!IS_ERR(xadir) && d_really_is_negative(xadir)) { + int err = -ENODATA; + + if (xattr_may_create(flags)) + err = xattr_mkdir(d_inode(xaroot), xadir, 0700); + if (err) { + dput(xadir); + xadir = ERR_PTR(err); + } + } + + inode_unlock(d_inode(xaroot)); + 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 dir_context ctx; + struct dentry *xadir; + int count; + int err; + struct dentry *dentries[8]; +}; + +static bool +fill_with_dentries(struct dir_context *ctx, const char *name, int namelen, + loff_t offset, u64 ino, unsigned int d_type) +{ + struct reiserfs_dentry_buf *dbuf = + container_of(ctx, struct reiserfs_dentry_buf, ctx); + struct dentry *dentry; + + WARN_ON_ONCE(!inode_is_locked(d_inode(dbuf->xadir))); + + if (dbuf->count == ARRAY_SIZE(dbuf->dentries)) + return false; + + if (name[0] == '.' && (namelen < 2 || + (namelen == 2 && name[1] == '.'))) + return true; + + dentry = lookup_one_len(name, dbuf->xadir, namelen); + if (IS_ERR(dentry)) { + dbuf->err = PTR_ERR(dentry); + return false; + } else if (d_really_is_negative(dentry)) { + /* A directory entry exists, but no file? */ + reiserfs_error(dentry->d_sb, "xattr-20003", + "Corrupted directory: xattr %pd listed but " + "not found for file %pd.\n", + dentry, dbuf->xadir); + dput(dentry); + dbuf->err = -EIO; + return false; + } + + dbuf->dentries[dbuf->count++] = dentry; + return true; +} + +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; + struct reiserfs_dentry_buf buf = { + .ctx.actor = fill_with_dentries, + }; + + /* Skip out, an xattr has no xattrs associated with it */ + if (IS_PRIVATE(inode) || get_inode_sd_version(inode) == STAT_DATA_V1) + return 0; + + dir = open_xa_dir(inode, XATTR_REPLACE); + if (IS_ERR(dir)) { + err = PTR_ERR(dir); + goto out; + } else if (d_really_is_negative(dir)) { + err = 0; + goto out_dir; + } + + inode_lock_nested(d_inode(dir), I_MUTEX_XATTR); + + buf.xadir = dir; + while (1) { + err = reiserfs_readdir_inode(d_inode(dir), &buf.ctx); + if (err) + break; + if (buf.err) { + err = buf.err; + break; + } + if (!buf.count) + break; + for (i = 0; !err && i < buf.count && buf.dentries[i]; i++) { + struct dentry *dentry = buf.dentries[i]; + + if (!d_is_dir(dentry)) + err = action(dentry, data); + + dput(dentry); + buf.dentries[i] = NULL; + } + if (err) + break; + buf.count = 0; + } + inode_unlock(d_inode(dir)); + + 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; + + reiserfs_write_lock(inode->i_sb); + err = journal_begin(&th, inode->i_sb, blocks); + reiserfs_write_unlock(inode->i_sb); + if (!err) { + int jerror; + + inode_lock_nested(d_inode(dir->d_parent), + I_MUTEX_XATTR); + err = action(dir, data); + reiserfs_write_lock(inode->i_sb); + jerror = journal_end(&th); + reiserfs_write_unlock(inode->i_sb); + inode_unlock(d_inode(dir->d_parent)); + err = jerror ?: err; + } + } +out_dir: + dput(dir); +out: + /* + * -ENODATA: this object doesn't have any xattrs + * -EOPNOTSUPP: this file system doesn't have xattrs enabled on disk. + * Neither are errors + */ + if (err == -ENODATA || err == -EOPNOTSUPP) + err = 0; + return err; +} + +static int delete_one_xattr(struct dentry *dentry, void *data) +{ + struct inode *dir = d_inode(dentry->d_parent); + + /* This is the xattr dir, handle specially. */ + if (d_is_dir(dentry)) + return xattr_rmdir(dir, dentry); + + return xattr_unlink(dir, dentry); +} + +static int chown_one_xattr(struct dentry *dentry, void *data) +{ + struct iattr *attrs = data; + int ia_valid = attrs->ia_valid; + int err; + + /* + * We only want the ownership bits. Otherwise, we'll do + * things like change a directory to a regular file if + * ATTR_MODE is set. + */ + attrs->ia_valid &= (ATTR_UID|ATTR_GID); + err = reiserfs_setattr(&init_user_ns, dentry, attrs); + attrs->ia_valid = ia_valid; + + return err; +} + +/* 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); + + inode_lock_nested(d_inode(xadir), I_MUTEX_XATTR); + xafile = lookup_one_len(name, xadir, strlen(name)); + if (IS_ERR(xafile)) { + err = PTR_ERR(xafile); + goto out; + } + + if (d_really_is_positive(xafile) && (flags & XATTR_CREATE)) + err = -EEXIST; + + if (d_really_is_negative(xafile)) { + err = -ENODATA; + if (xattr_may_create(flags)) + err = xattr_create(d_inode(xadir), xafile, + 0700|S_IFREG); + } + + if (err) + dput(xafile); +out: + inode_unlock(d_inode(xadir)); + 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); + put_page(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 occurred - GFP_NOFS avoids this + */ + mapping_set_gfp_mask(mapping, GFP_NOFS); + page = read_mapping_page(mapping, n >> PAGE_SHIFT, NULL); + if (!IS_ERR(page)) + kmap(page); + return page; +} + +static inline __u32 xattr_hash(const char *msg, int len) +{ + /* + * csum_partial() gives different results for little-endian and + * big endian hosts. Images created on little-endian hosts and + * mounted on big-endian hosts(and vice versa) will see csum mismatches + * when trying to fetch xattrs. Treating the hash as __wsum_t would + * lower the frequency of mismatch. This is an endianness bug in + * reiserfs. The return statement would result in a sparse warning. Do + * not fix the sparse warning so as to not hide a reminder of the bug. + */ + return csum_partial(msg, len, 0); +} + +int reiserfs_commit_write(struct file *f, struct page *page, + unsigned from, unsigned to); + +static void update_ctime(struct inode *inode) +{ + struct timespec64 now = current_time(inode); + + if (inode_unhashed(inode) || !inode->i_nlink || + timespec64_equal(&inode->i_ctime, &now)) + return; + + inode->i_ctime = current_time(inode); + 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); + + inode_lock_nested(d_inode(xadir), I_MUTEX_XATTR); + dentry = lookup_one_len(name, xadir, strlen(name)); + if (IS_ERR(dentry)) { + err = PTR_ERR(dentry); + goto out_dput; + } + + if (d_really_is_positive(dentry)) { + err = xattr_unlink(d_inode(xadir), dentry); + update_ctime(inode); + } + + dput(dentry); +out_dput: + inode_unlock(d_inode(xadir)); + 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; + + if (!buffer) { + err = lookup_and_delete_xattr(inode, name); + return err; + } + + dentry = xattr_lookup(inode, name, flags); + if (IS_ERR(dentry)) + return PTR_ERR(dentry); + + down_write(&REISERFS_I(inode)->i_xattr_sem); + + 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_SIZE - 1)); + + if (buffer_size - buffer_pos > PAGE_SIZE) + chunk = PAGE_SIZE; + else + chunk = buffer_size - buffer_pos; + + page = reiserfs_get_page(d_inode(dentry), 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_SIZE) + chunk = PAGE_SIZE - skip; + rxh = (struct reiserfs_xattr_header *)data; + rxh->h_magic = cpu_to_le32(REISERFS_XATTR_MAGIC); + rxh->h_hash = cpu_to_le32(xahash); + } + + reiserfs_write_lock(inode->i_sb); + err = __reiserfs_write_begin(page, 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); + } + reiserfs_write_unlock(inode->i_sb); + 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(d_inode(dentry))) { + struct iattr newattrs = { + .ia_ctime = current_time(inode), + .ia_size = new_size, + .ia_valid = ATTR_SIZE | ATTR_CTIME, + }; + + inode_lock_nested(d_inode(dentry), I_MUTEX_XATTR); + inode_dio_wait(d_inode(dentry)); + + err = reiserfs_setattr(&init_user_ns, dentry, &newattrs); + inode_unlock(d_inode(dentry)); + } 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); + + /* Check before we start a transaction and then do nothing. */ + if (!d_really_is_positive(REISERFS_SB(inode->i_sb)->priv_root)) + return -EOPNOTSUPP; + + 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); + reiserfs_write_unlock(inode->i_sb); + if (error) { + return error; + } + + error = reiserfs_xattr_set_handle(&th, inode, name, + buffer, buffer_size, flags); + + reiserfs_write_lock(inode->i_sb); + error2 = journal_end(&th); + reiserfs_write_unlock(inode->i_sb); + if (error == 0) + error = error2; + + 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; + + /* + * priv_root needn't be initialized during mount so allow initial + * lookups to succeed. + */ + if (!REISERFS_SB(inode->i_sb)->priv_root) + return 0; + + 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(d_inode(dentry)); + + /* 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_SIZE) + chunk = PAGE_SIZE; + else + chunk = isize - file_pos; + + page = reiserfs_get_page(d_inode(dentry), 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 const struct xattr_handler * +find_xattr_handler_prefix(const struct xattr_handler **handlers, + const char *name) +{ + const struct xattr_handler *xah; + + if (!handlers) + return NULL; + + for_each_xattr_handler(handlers, xah) { + const char *prefix = xattr_prefix(xah); + if (strncmp(prefix, name, strlen(prefix)) == 0) + break; + } + + return xah; +} + +struct listxattr_buf { + struct dir_context ctx; + size_t size; + size_t pos; + char *buf; + struct dentry *dentry; +}; + +static bool listxattr_filler(struct dir_context *ctx, const char *name, + int namelen, loff_t offset, u64 ino, + unsigned int d_type) +{ + struct listxattr_buf *b = + container_of(ctx, struct listxattr_buf, ctx); + size_t size; + + if (name[0] != '.' || + (namelen != 1 && (name[1] != '.' || namelen != 2))) { + const struct xattr_handler *handler; + + handler = find_xattr_handler_prefix(b->dentry->d_sb->s_xattr, + name); + if (!handler /* Unsupported xattr name */ || + (handler->list && !handler->list(b->dentry))) + return true; + size = namelen + 1; + if (b->buf) { + if (b->pos + size > b->size) { + b->pos = -ERANGE; + return false; + } + memcpy(b->buf + b->pos, name, namelen); + b->buf[b->pos + namelen] = 0; + } + b->pos += size; + } + return true; +} + +/* + * 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; + struct listxattr_buf buf = { + .ctx.actor = listxattr_filler, + .dentry = dentry, + .buf = buffer, + .size = buffer ? size : 0, + }; + + if (d_really_is_negative(dentry)) + return -EINVAL; + + if (get_inode_sd_version(d_inode(dentry)) == STAT_DATA_V1) + return -EOPNOTSUPP; + + dir = open_xa_dir(d_inode(dentry), 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; + } + + inode_lock_nested(d_inode(dir), I_MUTEX_XATTR); + err = reiserfs_readdir_inode(d_inode(dir), &buf.ctx); + inode_unlock(d_inode(dir)); + + if (!err) + err = buf.pos; + + dput(dir); +out: + return err; +} + +static int create_privroot(struct dentry *dentry) +{ + int err; + struct inode *inode = d_inode(dentry->d_parent); + + WARN_ON_ONCE(!inode_is_locked(inode)); + + err = xattr_mkdir(inode, dentry, 0700); + if (err || d_really_is_negative(dentry)) { + reiserfs_warning(dentry->d_sb, "jdm-20006", + "xattrs/ACLs enabled and couldn't " + "find/create .reiserfs_priv. " + "Failing mount."); + return -EOPNOTSUPP; + } + + d_inode(dentry)->i_flags |= S_PRIVATE; + d_inode(dentry)->i_opflags &= ~IOP_XATTR; + 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 */ +const 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 + &posix_acl_access_xattr_handler, + &posix_acl_default_xattr_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 user_namespace *mnt_userns, 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; + + return generic_permission(&init_user_ns, inode, mask); +} + +static int xattr_hide_revalidate(struct dentry *dentry, unsigned int flags) +{ + return -EPERM; +} + +static const struct dentry_operations xattr_lookup_poison_ops = { + .d_revalidate = xattr_hide_revalidate, +}; + +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 */ + inode_lock(d_inode(s->s_root)); + dentry = lookup_one_len(PRIVROOT_NAME, s->s_root, + strlen(PRIVROOT_NAME)); + if (!IS_ERR(dentry)) { + REISERFS_SB(s)->priv_root = dentry; + d_set_d_op(dentry, &xattr_lookup_poison_ops); + if (d_really_is_positive(dentry)) { + d_inode(dentry)->i_flags |= S_PRIVATE; + d_inode(dentry)->i_opflags &= ~IOP_XATTR; + } + } else + err = PTR_ERR(dentry); + inode_unlock(d_inode(s->s_root)); + + return err; +} + +/* + * We need to take a copy of the mount flags since things like + * SB_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 (d_really_is_negative(privroot) && !(mount_flags & SB_RDONLY)) { + inode_lock(d_inode(s->s_root)); + err = create_privroot(REISERFS_SB(s)->priv_root); + inode_unlock(d_inode(s->s_root)); + } + + if (d_really_is_positive(privroot)) { + inode_lock(d_inode(privroot)); + 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); + } + inode_unlock(d_inode(privroot)); + } + +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 SB_POSIXACL must mirror the (no)acl mount option. */ + if (reiserfs_posixacl(s)) + s->s_flags |= SB_POSIXACL; + else + s->s_flags &= ~SB_POSIXACL; + + return err; +} |