original development tree for Linux kernel GTP module; now long in mainline.
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/*
* 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 "xattr.h"
#include "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, umode_t 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);
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);
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 occurred - 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);
static void update_ctime(struct inode *inode)
{
struct timespec now = current_fs_time(inode->i_sb);
if (inode_unhashed(inode) || !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_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);
}
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 = new_size,
.ia_valid = ATTR_SIZE | ATTR_CTIME,
};
reiserfs_write_unlock(inode->i_sb);
mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_XATTR);
inode_dio_wait(dentry->d_inode);
reiserfs_write_lock(inode->i_sb);
err = reiserfs_setattr(dentry, &newattrs);
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 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) {
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)
{
const 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)
{
const 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)
{
const 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))) {
const 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 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 */
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
&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;
return generic_permission(inode, mask);
}
static int xattr_hide_revalidate(struct dentry *dentry, struct nameidata *nd)
{
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 */
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;
d_set_d_op(dentry, &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;
}