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DEFINITIONS
This source file includes following definitions.
- get_xa_root
- open_xa_dir
- get_xa_file_dentry
- __xattr_readdir
- xattr_readdir
- reiserfs_put_page
- reiserfs_get_page
- xattr_hash
- reiserfs_xattr_set
- reiserfs_xattr_get
- __reiserfs_xattr_del
- reiserfs_xattr_del
- reiserfs_delete_xattrs_filler
- reiserfs_delete_xattrs
- reiserfs_chown_xattrs_filler
- reiserfs_chown_xattrs
- reiserfs_getxattr
- reiserfs_setxattr
- reiserfs_removexattr
- reiserfs_listxattr_filler
- reiserfs_listxattr
- find_xattr_handler_prefix
- __unregister_handlers
- reiserfs_xattr_register_handlers
- reiserfs_xattr_unregister_handlers
- xattr_lookup_poison
- reiserfs_xattr_init
- reiserfs_check_acl
- reiserfs_permission
/*
* 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/capability.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 <asm/uaccess.h>
#include <net/checksum.h>
#include <linux/smp_lock.h>
#include <linux/stat.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);
/* Returns the dentry referring to the root of the extended attribute
* directory tree. If it has already been retrieved, it is used. If it
* hasn't been created and the flags indicate creation is allowed, we
* attempt to create it. On error, we return a pointer-encoded error.
*/
static struct dentry *get_xa_root(struct super_block *sb, int flags)
{
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(-ENODATA);
mutex_lock_nested(&privroot->d_inode->i_mutex, I_MUTEX_XATTR);
if (REISERFS_SB(sb)->xattr_root) {
xaroot = dget(REISERFS_SB(sb)->xattr_root);
goto out;
}
xaroot = lookup_one_len(XAROOT_NAME, privroot, strlen(XAROOT_NAME));
if (IS_ERR(xaroot)) {
goto out;
} else if (!xaroot->d_inode) {
int err = -ENODATA;
if (flags == 0 || flags & XATTR_CREATE)
err = privroot->d_inode->i_op->mkdir(privroot->d_inode,
xaroot, 0700);
if (err) {
dput(xaroot);
xaroot = ERR_PTR(err);
goto out;
}
}
REISERFS_SB(sb)->xattr_root = dget(xaroot);
out:
mutex_unlock(&privroot->d_inode->i_mutex);
dput(privroot);
return xaroot;
}
/* 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, flags);
if (IS_ERR(xaroot))
return xaroot;
/* 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_CAST(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_CAST(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_mutex 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);
else if (!xafile->d_inode) {
dput(xafile);
xafile = ERR_PTR(-ENODATA);
}
return xafile;
}
/*
* 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_mutex held, so there are no worries about the directory
* changing underneath us.
*/
static int __xattr_readdir(struct inode *inode, void *dirent, filldir_t filldir)
{
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 = kmalloc(d_reclen, GFP_NOFS);
if (!local_buf) {
pathrelse(&path_to_entry);
return -ENOMEM;
}
if (item_moved(&tmp_ih, &path_to_entry)) {
kfree(local_buf);
/* 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) {
kfree(local_buf);
}
goto end;
}
if (local_buf != small_buf) {
kfree(local_buf);
}
} /* 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 inode *inode, filldir_t filler, void *buf)
{
int res = -ENOENT;
mutex_lock_nested(&inode->i_mutex, I_MUTEX_XATTR);
if (!IS_DEADDIR(inode)) {
lock_kernel();
res = __xattr_readdir(inode, buf, filler);
unlock_kernel();
}
mutex_unlock(&inode->i_mutex);
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_set_gfp_mask(mapping, GFP_NOFS);
page = read_mapping_page(mapping, n, 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);
/* Generic extended attribute operations that can be used by xa plugins */
/*
* inode->i_mutex: down
*/
int
reiserfs_xattr_set(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;
struct address_space *mapping;
size_t file_pos = 0;
size_t buffer_pos = 0;
struct inode *xinode;
struct iattr newattrs;
__u32 xahash = 0;
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:
dentry = get_xa_file_dentry(inode, name, flags);
if (IS_ERR(dentry)) {
err = PTR_ERR(dentry);
goto out;
}
xinode = dentry->d_inode;
REISERFS_I(inode)->i_flags |= i_has_xattr_dir;
/* we need to copy it off.. */
if (xinode->i_nlink > 1) {
dput(dentry);
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;
mutex_lock_nested(&xinode->i_mutex, I_MUTEX_XATTR);
err = notify_change(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 = 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;
}
/* 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:
mutex_unlock(&xinode->i_mutex);
dput(dentry);
out:
return err;
}
/*
* inode->i_mutex: down
*/
int
reiserfs_xattr_get(const 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;
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;
dentry = get_xa_file_dentry(inode, name, FL_READONLY);
if (IS_ERR(dentry)) {
err = PTR_ERR(dentry);
goto out;
}
xinode = 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:
dput(dentry);
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;
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, u64 ino, unsigned int d_type)
{
struct dentry *xadir = (struct dentry *)buf;
return __reiserfs_xattr_del(xadir, name, namelen);
}
/* This is called w/ inode->i_mutex downed */
int reiserfs_delete_xattrs(struct inode *inode)
{
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;
}
lock_kernel();
err = xattr_readdir(dir->d_inode, 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, XATTR_REPLACE);
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:
dput(dir);
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, u64 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 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;
}
lock_kernel();
attrs->ia_valid &= (ATTR_UID | ATTR_GID | ATTR_CTIME);
buf.xadir = dir;
buf.attrs = attrs;
buf.inode = inode;
err = xattr_readdir(dir->d_inode, reiserfs_chown_xattrs_filler, &buf);
if (err) {
unlock_kernel();
goto out_dir;
}
err = notify_change(dir, attrs);
unlock_kernel();
out_dir:
dput(dir);
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_mutex
*/
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_mutex 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;
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_mutex 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;
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, u64 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_mutex
*/
ssize_t reiserfs_listxattr(struct dentry * dentry, char *buffer, size_t size)
{
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;
}
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(dir->d_inode, 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:
dput(dir);
out:
reiserfs_read_unlock_xattr_i(dentry->d_inode);
return err;
}
/* This is the implementation for the xattr plugin infrastructure */
static LIST_HEAD(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;
mutex_lock_nested(&inode->i_mutex,
I_MUTEX_XATTR);
err = inode->i_op->mkdir(inode, dentry, 0700);
mutex_unlock(&inode->i_mutex);
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_check_acl(struct inode *inode, int mask)
{
struct posix_acl *acl;
int error = -EAGAIN; /* do regular unix permission checks by default */
reiserfs_read_lock_xattr_i(inode);
reiserfs_read_lock_xattrs(inode->i_sb);
acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS);
reiserfs_read_unlock_xattrs(inode->i_sb);
reiserfs_read_unlock_xattr_i(inode);
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;
}
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_reiserfs_priv_object(inode))
return 0;
/*
* Stat data v1 doesn't support ACLs.
*/
if (get_inode_sd_version(inode) == STAT_DATA_V1)
return generic_permission(inode, mask, NULL);
else
return generic_permission(inode, mask, reiserfs_check_acl);
}