swh:1:snp:32555a3fd8878f019c2ebd6c964bc1edcaeff337
Tip revision: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 authored by Linus Torvalds on 16 April 2005, 22:20:36 UTC
Linux-2.6.12-rc2
Linux-2.6.12-rc2
Tip revision: 1da177e
xattr.c
/*
* linux/fs/reiserfs/xattr.c
*
* Copyright (c) 2002 by Jeff Mahoney, <jeffm@suse.com>
*
*/
/*
* In order to implement EA/ACLs in a clean, backwards compatible manner,
* they are implemented as files in a "private" directory.
* Each EA is in it's own file, with the directory layout like so (/ is assumed
* to be relative to fs root). Inside the /.reiserfs_priv/xattrs directory,
* directories named using the capital-hex form of the objectid and
* generation number are used. Inside each directory are individual files
* named with the name of the extended attribute.
*
* So, for objectid 12648430, we could have:
* /.reiserfs_priv/xattrs/C0FFEE.0/system.posix_acl_access
* /.reiserfs_priv/xattrs/C0FFEE.0/system.posix_acl_default
* /.reiserfs_priv/xattrs/C0FFEE.0/user.Content-Type
* .. or similar.
*
* The file contents are the text of the EA. The size is known based on the
* stat data describing the file.
*
* In the case of system.posix_acl_access and system.posix_acl_default, since
* these are special cases for filesystem ACLs, they are interpreted by the
* kernel, in addition, they are negatively and positively cached and attached
* to the inode so that unnecessary lookups are avoided.
*/
#include <linux/reiserfs_fs.h>
#include <linux/dcache.h>
#include <linux/namei.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/pagemap.h>
#include <linux/xattr.h>
#include <linux/reiserfs_xattr.h>
#include <linux/reiserfs_acl.h>
#include <linux/mbcache.h>
#include <asm/uaccess.h>
#include <asm/checksum.h>
#include <linux/smp_lock.h>
#include <linux/stat.h>
#include <asm/semaphore.h>
#define FL_READONLY 128
#define FL_DIR_SEM_HELD 256
#define PRIVROOT_NAME ".reiserfs_priv"
#define XAROOT_NAME "xattrs"
static struct reiserfs_xattr_handler *find_xattr_handler_prefix (const char *prefix);
static struct dentry *
create_xa_root (struct super_block *sb)
{
struct dentry *privroot = dget (REISERFS_SB(sb)->priv_root);
struct dentry *xaroot;
/* This needs to be created at mount-time */
if (!privroot)
return ERR_PTR(-EOPNOTSUPP);
xaroot = lookup_one_len (XAROOT_NAME, privroot, strlen (XAROOT_NAME));
if (IS_ERR (xaroot)) {
goto out;
} else if (!xaroot->d_inode) {
int err;
down (&privroot->d_inode->i_sem);
err = privroot->d_inode->i_op->mkdir (privroot->d_inode, xaroot, 0700);
up (&privroot->d_inode->i_sem);
if (err) {
dput (xaroot);
dput (privroot);
return ERR_PTR (err);
}
REISERFS_SB(sb)->xattr_root = dget (xaroot);
}
out:
dput (privroot);
return xaroot;
}
/* This will return a dentry, or error, refering to the xa root directory.
* If the xa root doesn't exist yet, the dentry will be returned without
* an associated inode. This dentry can be used with ->mkdir to create
* the xa directory. */
static struct dentry *
__get_xa_root (struct super_block *s)
{
struct dentry *privroot = dget (REISERFS_SB(s)->priv_root);
struct dentry *xaroot = NULL;
if (IS_ERR (privroot) || !privroot)
return privroot;
xaroot = lookup_one_len (XAROOT_NAME, privroot, strlen (XAROOT_NAME));
if (IS_ERR (xaroot)) {
goto out;
} else if (!xaroot->d_inode) {
dput (xaroot);
xaroot = NULL;
goto out;
}
REISERFS_SB(s)->xattr_root = dget (xaroot);
out:
dput (privroot);
return xaroot;
}
/* Returns the dentry (or NULL) referring to the root of the extended
* attribute directory tree. If it has already been retreived, it is used.
* Otherwise, we attempt to retreive it from disk. It may also return
* a pointer-encoded error.
*/
static inline struct dentry *
get_xa_root (struct super_block *s)
{
struct dentry *dentry = dget (REISERFS_SB(s)->xattr_root);
if (!dentry)
dentry = __get_xa_root (s);
return dentry;
}
/* Opens the directory corresponding to the inode's extended attribute store.
* If flags allow, the tree to the directory may be created. If creation is
* prohibited, -ENODATA is returned. */
static struct dentry *
open_xa_dir (const struct inode *inode, int flags)
{
struct dentry *xaroot, *xadir;
char namebuf[17];
xaroot = get_xa_root (inode->i_sb);
if (IS_ERR (xaroot)) {
return xaroot;
} else if (!xaroot) {
if (flags == 0 || flags & XATTR_CREATE) {
xaroot = create_xa_root (inode->i_sb);
if (IS_ERR (xaroot))
return xaroot;
}
if (!xaroot)
return ERR_PTR (-ENODATA);
}
/* ok, we have xaroot open */
snprintf (namebuf, sizeof (namebuf), "%X.%X",
le32_to_cpu (INODE_PKEY (inode)->k_objectid),
inode->i_generation);
xadir = lookup_one_len (namebuf, xaroot, strlen (namebuf));
if (IS_ERR (xadir)) {
dput (xaroot);
return xadir;
}
if (!xadir->d_inode) {
int err;
if (flags == 0 || flags & XATTR_CREATE) {
/* Although there is nothing else trying to create this directory,
* another directory with the same hash may be created, so we need
* to protect against that */
err = xaroot->d_inode->i_op->mkdir (xaroot->d_inode, xadir, 0700);
if (err) {
dput (xaroot);
dput (xadir);
return ERR_PTR (err);
}
}
if (!xadir->d_inode) {
dput (xaroot);
dput (xadir);
return ERR_PTR (-ENODATA);
}
}
dput (xaroot);
return xadir;
}
/* Returns a dentry corresponding to a specific extended attribute file
* for the inode. If flags allow, the file is created. Otherwise, a
* valid or negative dentry, or an error is returned. */
static struct dentry *
get_xa_file_dentry (const struct inode *inode, const char *name, int flags)
{
struct dentry *xadir, *xafile;
int err = 0;
xadir = open_xa_dir (inode, flags);
if (IS_ERR (xadir)) {
return ERR_PTR (PTR_ERR (xadir));
} else if (xadir && !xadir->d_inode) {
dput (xadir);
return ERR_PTR (-ENODATA);
}
xafile = lookup_one_len (name, xadir, strlen (name));
if (IS_ERR (xafile)) {
dput (xadir);
return ERR_PTR (PTR_ERR (xafile));
}
if (xafile->d_inode) { /* file exists */
if (flags & XATTR_CREATE) {
err = -EEXIST;
dput (xafile);
goto out;
}
} else if (flags & XATTR_REPLACE || flags & FL_READONLY) {
goto out;
} else {
/* inode->i_sem is down, so nothing else can try to create
* the same xattr */
err = xadir->d_inode->i_op->create (xadir->d_inode, xafile,
0700|S_IFREG, NULL);
if (err) {
dput (xafile);
goto out;
}
}
out:
dput (xadir);
if (err)
xafile = ERR_PTR (err);
return xafile;
}
/* Opens a file pointer to the attribute associated with inode */
static struct file *
open_xa_file (const struct inode *inode, const char *name, int flags)
{
struct dentry *xafile;
struct file *fp;
xafile = get_xa_file_dentry (inode, name, flags);
if (IS_ERR (xafile))
return ERR_PTR (PTR_ERR (xafile));
else if (!xafile->d_inode) {
dput (xafile);
return ERR_PTR (-ENODATA);
}
fp = dentry_open (xafile, NULL, O_RDWR);
/* dentry_open dputs the dentry if it fails */
return fp;
}
/*
* this is very similar to fs/reiserfs/dir.c:reiserfs_readdir, but
* we need to drop the path before calling the filldir struct. That
* would be a big performance hit to the non-xattr case, so I've copied
* the whole thing for now. --clm
*
* the big difference is that I go backwards through the directory,
* and don't mess with f->f_pos, but the idea is the same. Do some
* action on each and every entry in the directory.
*
* we're called with i_sem held, so there are no worries about the directory
* changing underneath us.
*/
static int __xattr_readdir(struct file * filp, void * dirent, filldir_t filldir)
{
struct inode *inode = filp->f_dentry->d_inode;
struct cpu_key pos_key; /* key of current position in the directory (key of directory entry) */
INITIALIZE_PATH (path_to_entry);
struct buffer_head * bh;
int entry_num;
struct item_head * ih, tmp_ih;
int search_res;
char * local_buf;
loff_t next_pos;
char small_buf[32] ; /* avoid kmalloc if we can */
struct reiserfs_de_head *deh;
int d_reclen;
char * d_name;
off_t d_off;
ino_t d_ino;
struct reiserfs_dir_entry de;
/* form key for search the next directory entry using f_pos field of
file structure */
next_pos = max_reiserfs_offset(inode);
while (1) {
research:
if (next_pos <= DOT_DOT_OFFSET)
break;
make_cpu_key (&pos_key, inode, next_pos, TYPE_DIRENTRY, 3);
search_res = search_by_entry_key(inode->i_sb, &pos_key, &path_to_entry, &de);
if (search_res == IO_ERROR) {
// FIXME: we could just skip part of directory which could
// not be read
pathrelse(&path_to_entry);
return -EIO;
}
if (search_res == NAME_NOT_FOUND)
de.de_entry_num--;
set_de_name_and_namelen(&de);
entry_num = de.de_entry_num;
deh = &(de.de_deh[entry_num]);
bh = de.de_bh;
ih = de.de_ih;
if (!is_direntry_le_ih(ih)) {
reiserfs_warning(inode->i_sb, "not direntry %h", ih);
break;
}
copy_item_head(&tmp_ih, ih);
/* we must have found item, that is item of this directory, */
RFALSE( COMP_SHORT_KEYS (&(ih->ih_key), &pos_key),
"vs-9000: found item %h does not match to dir we readdir %K",
ih, &pos_key);
if (deh_offset(deh) <= DOT_DOT_OFFSET) {
break;
}
/* look for the previous entry in the directory */
next_pos = deh_offset (deh) - 1;
if (!de_visible (deh))
/* it is hidden entry */
continue;
d_reclen = entry_length(bh, ih, entry_num);
d_name = B_I_DEH_ENTRY_FILE_NAME (bh, ih, deh);
d_off = deh_offset (deh);
d_ino = deh_objectid (deh);
if (!d_name[d_reclen - 1])
d_reclen = strlen (d_name);
if (d_reclen > REISERFS_MAX_NAME(inode->i_sb->s_blocksize)){
/* too big to send back to VFS */
continue ;
}
/* Ignore the .reiserfs_priv entry */
if (reiserfs_xattrs (inode->i_sb) &&
!old_format_only(inode->i_sb) &&
deh_objectid (deh) == le32_to_cpu (INODE_PKEY(REISERFS_SB(inode->i_sb)->priv_root->d_inode)->k_objectid))
continue;
if (d_reclen <= 32) {
local_buf = small_buf ;
} else {
local_buf = reiserfs_kmalloc(d_reclen, GFP_NOFS, inode->i_sb) ;
if (!local_buf) {
pathrelse (&path_to_entry);
return -ENOMEM ;
}
if (item_moved (&tmp_ih, &path_to_entry)) {
reiserfs_kfree(local_buf, d_reclen, inode->i_sb) ;
/* sigh, must retry. Do this same offset again */
next_pos = d_off;
goto research;
}
}
// Note, that we copy name to user space via temporary
// buffer (local_buf) because filldir will block if
// user space buffer is swapped out. At that time
// entry can move to somewhere else
memcpy (local_buf, d_name, d_reclen);
/* the filldir function might need to start transactions,
* or do who knows what. Release the path now that we've
* copied all the important stuff out of the deh
*/
pathrelse (&path_to_entry);
if (filldir (dirent, local_buf, d_reclen, d_off, d_ino,
DT_UNKNOWN) < 0) {
if (local_buf != small_buf) {
reiserfs_kfree(local_buf, d_reclen, inode->i_sb) ;
}
goto end;
}
if (local_buf != small_buf) {
reiserfs_kfree(local_buf, d_reclen, inode->i_sb) ;
}
} /* while */
end:
pathrelse (&path_to_entry);
return 0;
}
/*
* this could be done with dedicated readdir ops for the xattr files,
* but I want to get something working asap
* this is stolen from vfs_readdir
*
*/
static
int xattr_readdir(struct file *file, filldir_t filler, void *buf)
{
struct inode *inode = file->f_dentry->d_inode;
int res = -ENOTDIR;
if (!file->f_op || !file->f_op->readdir)
goto out;
down(&inode->i_sem);
// down(&inode->i_zombie);
res = -ENOENT;
if (!IS_DEADDIR(inode)) {
lock_kernel();
res = __xattr_readdir(file, buf, filler);
unlock_kernel();
}
// up(&inode->i_zombie);
up(&inode->i_sem);
out:
return res;
}
/* Internal operations on file data */
static inline void
reiserfs_put_page(struct page *page)
{
kunmap(page);
page_cache_release(page);
}
static struct page *
reiserfs_get_page(struct inode *dir, unsigned long n)
{
struct address_space *mapping = dir->i_mapping;
struct page *page;
/* We can deadlock if we try to free dentries,
and an unlink/rmdir has just occured - GFP_NOFS avoids this */
mapping->flags = (mapping->flags & ~__GFP_BITS_MASK) | GFP_NOFS;
page = read_cache_page (mapping, n,
(filler_t*)mapping->a_ops->readpage, NULL);
if (!IS_ERR(page)) {
wait_on_page_locked(page);
kmap(page);
if (!PageUptodate(page))
goto fail;
if (PageError(page))
goto fail;
}
return page;
fail:
reiserfs_put_page(page);
return ERR_PTR(-EIO);
}
static inline __u32
xattr_hash (const char *msg, int len)
{
return csum_partial (msg, len, 0);
}
/* Generic extended attribute operations that can be used by xa plugins */
/*
* inode->i_sem: down
*/
int
reiserfs_xattr_set (struct inode *inode, const char *name, const void *buffer,
size_t buffer_size, int flags)
{
int err = 0;
struct file *fp;
struct page *page;
char *data;
struct address_space *mapping;
size_t file_pos = 0;
size_t buffer_pos = 0;
struct inode *xinode;
struct iattr newattrs;
__u32 xahash = 0;
if (IS_RDONLY (inode))
return -EROFS;
if (IS_IMMUTABLE (inode) || IS_APPEND (inode))
return -EPERM;
if (get_inode_sd_version (inode) == STAT_DATA_V1)
return -EOPNOTSUPP;
/* Empty xattrs are ok, they're just empty files, no hash */
if (buffer && buffer_size)
xahash = xattr_hash (buffer, buffer_size);
open_file:
fp = open_xa_file (inode, name, flags);
if (IS_ERR (fp)) {
err = PTR_ERR (fp);
goto out;
}
xinode = fp->f_dentry->d_inode;
REISERFS_I(inode)->i_flags |= i_has_xattr_dir;
/* we need to copy it off.. */
if (xinode->i_nlink > 1) {
fput(fp);
err = reiserfs_xattr_del (inode, name);
if (err < 0)
goto out;
/* We just killed the old one, we're not replacing anymore */
if (flags & XATTR_REPLACE)
flags &= ~XATTR_REPLACE;
goto open_file;
}
/* Resize it so we're ok to write there */
newattrs.ia_size = buffer_size;
newattrs.ia_valid = ATTR_SIZE | ATTR_CTIME;
down (&xinode->i_sem);
err = notify_change(fp->f_dentry, &newattrs);
if (err)
goto out_filp;
mapping = xinode->i_mapping;
while (buffer_pos < buffer_size || buffer_pos == 0) {
size_t chunk;
size_t skip = 0;
size_t page_offset = (file_pos & (PAGE_CACHE_SIZE - 1));
if (buffer_size - buffer_pos > PAGE_CACHE_SIZE)
chunk = PAGE_CACHE_SIZE;
else
chunk = buffer_size - buffer_pos;
page = reiserfs_get_page (xinode, file_pos >> PAGE_CACHE_SHIFT);
if (IS_ERR (page)) {
err = PTR_ERR (page);
goto out_filp;
}
lock_page (page);
data = page_address (page);
if (file_pos == 0) {
struct reiserfs_xattr_header *rxh;
skip = file_pos = sizeof (struct reiserfs_xattr_header);
if (chunk + skip > PAGE_CACHE_SIZE)
chunk = PAGE_CACHE_SIZE - skip;
rxh = (struct reiserfs_xattr_header *)data;
rxh->h_magic = cpu_to_le32 (REISERFS_XATTR_MAGIC);
rxh->h_hash = cpu_to_le32 (xahash);
}
err = mapping->a_ops->prepare_write (fp, page, page_offset,
page_offset + chunk + skip);
if (!err) {
if (buffer)
memcpy (data + skip, buffer + buffer_pos, chunk);
err = mapping->a_ops->commit_write (fp, page, page_offset,
page_offset + chunk + skip);
}
unlock_page (page);
reiserfs_put_page (page);
buffer_pos += chunk;
file_pos += chunk;
skip = 0;
if (err || buffer_size == 0 || !buffer)
break;
}
/* We can't mark the inode dirty if it's not hashed. This is the case
* when we're inheriting the default ACL. If we dirty it, the inode
* gets marked dirty, but won't (ever) make it onto the dirty list until
* it's synced explicitly to clear I_DIRTY. This is bad. */
if (!hlist_unhashed(&inode->i_hash)) {
inode->i_ctime = CURRENT_TIME_SEC;
mark_inode_dirty (inode);
}
out_filp:
up (&xinode->i_sem);
fput(fp);
out:
return err;
}
/*
* inode->i_sem: down
*/
int
reiserfs_xattr_get (const struct inode *inode, const char *name, void *buffer,
size_t buffer_size)
{
ssize_t err = 0;
struct file *fp;
size_t isize;
size_t file_pos = 0;
size_t buffer_pos = 0;
struct page *page;
struct inode *xinode;
__u32 hash = 0;
if (name == NULL)
return -EINVAL;
/* We can't have xattrs attached to v1 items since they don't have
* generation numbers */
if (get_inode_sd_version (inode) == STAT_DATA_V1)
return -EOPNOTSUPP;
fp = open_xa_file (inode, name, FL_READONLY);
if (IS_ERR (fp)) {
err = PTR_ERR (fp);
goto out;
}
xinode = fp->f_dentry->d_inode;
isize = xinode->i_size;
REISERFS_I(inode)->i_flags |= i_has_xattr_dir;
/* Just return the size needed */
if (buffer == NULL) {
err = isize - sizeof (struct reiserfs_xattr_header);
goto out_dput;
}
if (buffer_size < isize - sizeof (struct reiserfs_xattr_header)) {
err = -ERANGE;
goto out_dput;
}
while (file_pos < isize) {
size_t chunk;
char *data;
size_t skip = 0;
if (isize - file_pos > PAGE_CACHE_SIZE)
chunk = PAGE_CACHE_SIZE;
else
chunk = isize - file_pos;
page = reiserfs_get_page (xinode, file_pos >> PAGE_CACHE_SHIFT);
if (IS_ERR (page)) {
err = PTR_ERR (page);
goto out_dput;
}
lock_page (page);
data = page_address (page);
if (file_pos == 0) {
struct reiserfs_xattr_header *rxh =
(struct reiserfs_xattr_header *)data;
skip = file_pos = sizeof (struct reiserfs_xattr_header);
chunk -= skip;
/* Magic doesn't match up.. */
if (rxh->h_magic != cpu_to_le32 (REISERFS_XATTR_MAGIC)) {
unlock_page (page);
reiserfs_put_page (page);
reiserfs_warning (inode->i_sb, "Invalid magic for xattr (%s) "
"associated with %k", name,
INODE_PKEY (inode));
err = -EIO;
goto out_dput;
}
hash = le32_to_cpu (rxh->h_hash);
}
memcpy (buffer + buffer_pos, data + skip, chunk);
unlock_page (page);
reiserfs_put_page (page);
file_pos += chunk;
buffer_pos += chunk;
skip = 0;
}
err = isize - sizeof (struct reiserfs_xattr_header);
if (xattr_hash (buffer, isize - sizeof (struct reiserfs_xattr_header)) != hash) {
reiserfs_warning (inode->i_sb, "Invalid hash for xattr (%s) associated "
"with %k", name, INODE_PKEY (inode));
err = -EIO;
}
out_dput:
fput(fp);
out:
return err;
}
static int
__reiserfs_xattr_del (struct dentry *xadir, const char *name, int namelen)
{
struct dentry *dentry;
struct inode *dir = xadir->d_inode;
int err = 0;
dentry = lookup_one_len (name, xadir, namelen);
if (IS_ERR (dentry)) {
err = PTR_ERR (dentry);
goto out;
} else if (!dentry->d_inode) {
err = -ENODATA;
goto out_file;
}
/* Skip directories.. */
if (S_ISDIR (dentry->d_inode->i_mode))
goto out_file;
if (!is_reiserfs_priv_object (dentry->d_inode)) {
reiserfs_warning (dir->i_sb, "OID %08x [%.*s/%.*s] doesn't have "
"priv flag set [parent is %sset].",
le32_to_cpu (INODE_PKEY (dentry->d_inode)->k_objectid),
xadir->d_name.len, xadir->d_name.name, namelen, name,
is_reiserfs_priv_object (xadir->d_inode) ? "" : "not ");
dput (dentry);
return -EIO;
}
err = dir->i_op->unlink (dir, dentry);
if (!err)
d_delete (dentry);
out_file:
dput (dentry);
out:
return err;
}
int
reiserfs_xattr_del (struct inode *inode, const char *name)
{
struct dentry *dir;
int err;
if (IS_RDONLY (inode))
return -EROFS;
dir = open_xa_dir (inode, FL_READONLY);
if (IS_ERR (dir)) {
err = PTR_ERR (dir);
goto out;
}
err = __reiserfs_xattr_del (dir, name, strlen (name));
dput (dir);
if (!err) {
inode->i_ctime = CURRENT_TIME_SEC;
mark_inode_dirty (inode);
}
out:
return err;
}
/* The following are side effects of other operations that aren't explicitly
* modifying extended attributes. This includes operations such as permissions
* or ownership changes, object deletions, etc. */
static int
reiserfs_delete_xattrs_filler (void *buf, const char *name, int namelen,
loff_t offset, ino_t ino, unsigned int d_type)
{
struct dentry *xadir = (struct dentry *)buf;
return __reiserfs_xattr_del (xadir, name, namelen);
}
/* This is called w/ inode->i_sem downed */
int
reiserfs_delete_xattrs (struct inode *inode)
{
struct file *fp;
struct dentry *dir, *root;
int err = 0;
/* Skip out, an xattr has no xattrs associated with it */
if (is_reiserfs_priv_object (inode) ||
get_inode_sd_version (inode) == STAT_DATA_V1 ||
!reiserfs_xattrs(inode->i_sb))
{
return 0;
}
reiserfs_read_lock_xattrs (inode->i_sb);
dir = open_xa_dir (inode, FL_READONLY);
reiserfs_read_unlock_xattrs (inode->i_sb);
if (IS_ERR (dir)) {
err = PTR_ERR (dir);
goto out;
} else if (!dir->d_inode) {
dput (dir);
return 0;
}
fp = dentry_open (dir, NULL, O_RDWR);
if (IS_ERR (fp)) {
err = PTR_ERR (fp);
/* dentry_open dputs the dentry if it fails */
goto out;
}
lock_kernel ();
err = xattr_readdir (fp, reiserfs_delete_xattrs_filler, dir);
if (err) {
unlock_kernel ();
goto out_dir;
}
/* Leftovers besides . and .. -- that's not good. */
if (dir->d_inode->i_nlink <= 2) {
root = get_xa_root (inode->i_sb);
reiserfs_write_lock_xattrs (inode->i_sb);
err = vfs_rmdir (root->d_inode, dir);
reiserfs_write_unlock_xattrs (inode->i_sb);
dput (root);
} else {
reiserfs_warning (inode->i_sb,
"Couldn't remove all entries in directory");
}
unlock_kernel ();
out_dir:
fput(fp);
out:
if (!err)
REISERFS_I(inode)->i_flags = REISERFS_I(inode)->i_flags & ~i_has_xattr_dir;
return err;
}
struct reiserfs_chown_buf {
struct inode *inode;
struct dentry *xadir;
struct iattr *attrs;
};
/* XXX: If there is a better way to do this, I'd love to hear about it */
static int
reiserfs_chown_xattrs_filler (void *buf, const char *name, int namelen,
loff_t offset, ino_t ino, unsigned int d_type)
{
struct reiserfs_chown_buf *chown_buf = (struct reiserfs_chown_buf *)buf;
struct dentry *xafile, *xadir = chown_buf->xadir;
struct iattr *attrs = chown_buf->attrs;
int err = 0;
xafile = lookup_one_len (name, xadir, namelen);
if (IS_ERR (xafile))
return PTR_ERR (xafile);
else if (!xafile->d_inode) {
dput (xafile);
return -ENODATA;
}
if (!S_ISDIR (xafile->d_inode->i_mode))
err = notify_change (xafile, attrs);
dput (xafile);
return err;
}
int
reiserfs_chown_xattrs (struct inode *inode, struct iattr *attrs)
{
struct file *fp;
struct dentry *dir;
int err = 0;
struct reiserfs_chown_buf buf;
unsigned int ia_valid = attrs->ia_valid;
/* Skip out, an xattr has no xattrs associated with it */
if (is_reiserfs_priv_object (inode) ||
get_inode_sd_version (inode) == STAT_DATA_V1 ||
!reiserfs_xattrs(inode->i_sb))
{
return 0;
}
reiserfs_read_lock_xattrs (inode->i_sb);
dir = open_xa_dir (inode, FL_READONLY);
reiserfs_read_unlock_xattrs (inode->i_sb);
if (IS_ERR (dir)) {
if (PTR_ERR (dir) != -ENODATA)
err = PTR_ERR (dir);
goto out;
} else if (!dir->d_inode) {
dput (dir);
goto out;
}
fp = dentry_open (dir, NULL, O_RDWR);
if (IS_ERR (fp)) {
err = PTR_ERR (fp);
/* dentry_open dputs the dentry if it fails */
goto out;
}
lock_kernel ();
attrs->ia_valid &= (ATTR_UID | ATTR_GID | ATTR_CTIME);
buf.xadir = dir;
buf.attrs = attrs;
buf.inode = inode;
err = xattr_readdir (fp, reiserfs_chown_xattrs_filler, &buf);
if (err) {
unlock_kernel ();
goto out_dir;
}
err = notify_change (dir, attrs);
unlock_kernel ();
out_dir:
fput(fp);
out:
attrs->ia_valid = ia_valid;
return err;
}
/* Actual operations that are exported to VFS-land */
/*
* Inode operation getxattr()
* Preliminary locking: we down dentry->d_inode->i_sem
*/
ssize_t
reiserfs_getxattr (struct dentry *dentry, const char *name, void *buffer,
size_t size)
{
struct reiserfs_xattr_handler *xah = find_xattr_handler_prefix (name);
int err;
if (!xah || !reiserfs_xattrs(dentry->d_sb) ||
get_inode_sd_version (dentry->d_inode) == STAT_DATA_V1)
return -EOPNOTSUPP;
reiserfs_read_lock_xattr_i (dentry->d_inode);
reiserfs_read_lock_xattrs (dentry->d_sb);
err = xah->get (dentry->d_inode, name, buffer, size);
reiserfs_read_unlock_xattrs (dentry->d_sb);
reiserfs_read_unlock_xattr_i (dentry->d_inode);
return err;
}
/*
* Inode operation setxattr()
*
* dentry->d_inode->i_sem down
*/
int
reiserfs_setxattr (struct dentry *dentry, const char *name, const void *value,
size_t size, int flags)
{
struct reiserfs_xattr_handler *xah = find_xattr_handler_prefix (name);
int err;
int lock;
if (!xah || !reiserfs_xattrs(dentry->d_sb) ||
get_inode_sd_version (dentry->d_inode) == STAT_DATA_V1)
return -EOPNOTSUPP;
if (IS_RDONLY (dentry->d_inode))
return -EROFS;
if (IS_IMMUTABLE (dentry->d_inode) || IS_APPEND (dentry->d_inode))
return -EROFS;
reiserfs_write_lock_xattr_i (dentry->d_inode);
lock = !has_xattr_dir (dentry->d_inode);
if (lock)
reiserfs_write_lock_xattrs (dentry->d_sb);
else
reiserfs_read_lock_xattrs (dentry->d_sb);
err = xah->set (dentry->d_inode, name, value, size, flags);
if (lock)
reiserfs_write_unlock_xattrs (dentry->d_sb);
else
reiserfs_read_unlock_xattrs (dentry->d_sb);
reiserfs_write_unlock_xattr_i (dentry->d_inode);
return err;
}
/*
* Inode operation removexattr()
*
* dentry->d_inode->i_sem down
*/
int
reiserfs_removexattr (struct dentry *dentry, const char *name)
{
int err;
struct reiserfs_xattr_handler *xah = find_xattr_handler_prefix (name);
if (!xah || !reiserfs_xattrs(dentry->d_sb) ||
get_inode_sd_version (dentry->d_inode) == STAT_DATA_V1)
return -EOPNOTSUPP;
if (IS_RDONLY (dentry->d_inode))
return -EROFS;
if (IS_IMMUTABLE (dentry->d_inode) || IS_APPEND (dentry->d_inode))
return -EPERM;
reiserfs_write_lock_xattr_i (dentry->d_inode);
reiserfs_read_lock_xattrs (dentry->d_sb);
/* Deletion pre-operation */
if (xah->del) {
err = xah->del (dentry->d_inode, name);
if (err)
goto out;
}
err = reiserfs_xattr_del (dentry->d_inode, name);
dentry->d_inode->i_ctime = CURRENT_TIME_SEC;
mark_inode_dirty (dentry->d_inode);
out:
reiserfs_read_unlock_xattrs (dentry->d_sb);
reiserfs_write_unlock_xattr_i (dentry->d_inode);
return err;
}
/* This is what filldir will use:
* r_pos will always contain the amount of space required for the entire
* list. If r_pos becomes larger than r_size, we need more space and we
* return an error indicating this. If r_pos is less than r_size, then we've
* filled the buffer successfully and we return success */
struct reiserfs_listxattr_buf {
int r_pos;
int r_size;
char *r_buf;
struct inode *r_inode;
};
static int
reiserfs_listxattr_filler (void *buf, const char *name, int namelen,
loff_t offset, ino_t ino, unsigned int d_type)
{
struct reiserfs_listxattr_buf *b = (struct reiserfs_listxattr_buf *)buf;
int len = 0;
if (name[0] != '.' || (namelen != 1 && (name[1] != '.' || namelen != 2))) {
struct reiserfs_xattr_handler *xah = find_xattr_handler_prefix (name);
if (!xah) return 0; /* Unsupported xattr name, skip it */
/* We call ->list() twice because the operation isn't required to just
* return the name back - we want to make sure we have enough space */
len += xah->list (b->r_inode, name, namelen, NULL);
if (len) {
if (b->r_pos + len + 1 <= b->r_size) {
char *p = b->r_buf + b->r_pos;
p += xah->list (b->r_inode, name, namelen, p);
*p++ = '\0';
}
b->r_pos += len + 1;
}
}
return 0;
}
/*
* Inode operation listxattr()
*
* Preliminary locking: we down dentry->d_inode->i_sem
*/
ssize_t
reiserfs_listxattr (struct dentry *dentry, char *buffer, size_t size)
{
struct file *fp;
struct dentry *dir;
int err = 0;
struct reiserfs_listxattr_buf buf;
if (!dentry->d_inode)
return -EINVAL;
if (!reiserfs_xattrs(dentry->d_sb) ||
get_inode_sd_version (dentry->d_inode) == STAT_DATA_V1)
return -EOPNOTSUPP;
reiserfs_read_lock_xattr_i (dentry->d_inode);
reiserfs_read_lock_xattrs (dentry->d_sb);
dir = open_xa_dir (dentry->d_inode, FL_READONLY);
reiserfs_read_unlock_xattrs (dentry->d_sb);
if (IS_ERR (dir)) {
err = PTR_ERR (dir);
if (err == -ENODATA)
err = 0; /* Not an error if there aren't any xattrs */
goto out;
}
fp = dentry_open (dir, NULL, O_RDWR);
if (IS_ERR (fp)) {
err = PTR_ERR (fp);
/* dentry_open dputs the dentry if it fails */
goto out;
}
buf.r_buf = buffer;
buf.r_size = buffer ? size : 0;
buf.r_pos = 0;
buf.r_inode = dentry->d_inode;
REISERFS_I(dentry->d_inode)->i_flags |= i_has_xattr_dir;
err = xattr_readdir (fp, reiserfs_listxattr_filler, &buf);
if (err)
goto out_dir;
if (buf.r_pos > buf.r_size && buffer != NULL)
err = -ERANGE;
else
err = buf.r_pos;
out_dir:
fput(fp);
out:
reiserfs_read_unlock_xattr_i (dentry->d_inode);
return err;
}
/* This is the implementation for the xattr plugin infrastructure */
static struct list_head xattr_handlers = LIST_HEAD_INIT (xattr_handlers);
static DEFINE_RWLOCK(handler_lock);
static struct reiserfs_xattr_handler *
find_xattr_handler_prefix (const char *prefix)
{
struct reiserfs_xattr_handler *xah = NULL;
struct list_head *p;
read_lock (&handler_lock);
list_for_each (p, &xattr_handlers) {
xah = list_entry (p, struct reiserfs_xattr_handler, handlers);
if (strncmp (xah->prefix, prefix, strlen (xah->prefix)) == 0)
break;
xah = NULL;
}
read_unlock (&handler_lock);
return xah;
}
static void
__unregister_handlers (void)
{
struct reiserfs_xattr_handler *xah;
struct list_head *p, *tmp;
list_for_each_safe (p, tmp, &xattr_handlers) {
xah = list_entry (p, struct reiserfs_xattr_handler, handlers);
if (xah->exit)
xah->exit();
list_del_init (p);
}
INIT_LIST_HEAD (&xattr_handlers);
}
int __init
reiserfs_xattr_register_handlers (void)
{
int err = 0;
struct reiserfs_xattr_handler *xah;
struct list_head *p;
write_lock (&handler_lock);
/* If we're already initialized, nothing to do */
if (!list_empty (&xattr_handlers)) {
write_unlock (&handler_lock);
return 0;
}
/* Add the handlers */
list_add_tail (&user_handler.handlers, &xattr_handlers);
list_add_tail (&trusted_handler.handlers, &xattr_handlers);
#ifdef CONFIG_REISERFS_FS_SECURITY
list_add_tail (&security_handler.handlers, &xattr_handlers);
#endif
#ifdef CONFIG_REISERFS_FS_POSIX_ACL
list_add_tail (&posix_acl_access_handler.handlers, &xattr_handlers);
list_add_tail (&posix_acl_default_handler.handlers, &xattr_handlers);
#endif
/* Run initializers, if available */
list_for_each (p, &xattr_handlers) {
xah = list_entry (p, struct reiserfs_xattr_handler, handlers);
if (xah->init) {
err = xah->init ();
if (err) {
list_del_init (p);
break;
}
}
}
/* Clean up other handlers, if any failed */
if (err)
__unregister_handlers ();
write_unlock (&handler_lock);
return err;
}
void
reiserfs_xattr_unregister_handlers (void)
{
write_lock (&handler_lock);
__unregister_handlers ();
write_unlock (&handler_lock);
}
/* This will catch lookups from the fs root to .reiserfs_priv */
static int
xattr_lookup_poison (struct dentry *dentry, struct qstr *q1, struct qstr *name)
{
struct dentry *priv_root = REISERFS_SB(dentry->d_sb)->priv_root;
if (name->len == priv_root->d_name.len &&
name->hash == priv_root->d_name.hash &&
!memcmp (name->name, priv_root->d_name.name, name->len)) {
return -ENOENT;
} else if (q1->len == name->len &&
!memcmp(q1->name, name->name, name->len))
return 0;
return 1;
}
static struct dentry_operations xattr_lookup_poison_ops = {
.d_compare = xattr_lookup_poison,
};
/* We need to take a copy of the mount flags since things like
* MS_RDONLY don't get set until *after* we're called.
* mount_flags != mount_options */
int
reiserfs_xattr_init (struct super_block *s, int mount_flags)
{
int err = 0;
/* We need generation numbers to ensure that the oid mapping is correct
* v3.5 filesystems don't have them. */
if (!old_format_only (s)) {
set_bit (REISERFS_XATTRS, &(REISERFS_SB(s)->s_mount_opt));
} else if (reiserfs_xattrs_optional (s)) {
/* Old format filesystem, but optional xattrs have been enabled
* at mount time. Error out. */
reiserfs_warning (s, "xattrs/ACLs not supported on pre v3.6 "
"format filesystem. Failing mount.");
err = -EOPNOTSUPP;
goto error;
} else {
/* Old format filesystem, but no optional xattrs have been enabled. This
* means we silently disable xattrs on the filesystem. */
clear_bit (REISERFS_XATTRS, &(REISERFS_SB(s)->s_mount_opt));
}
/* If we don't have the privroot located yet - go find it */
if (reiserfs_xattrs (s) && !REISERFS_SB(s)->priv_root) {
struct dentry *dentry;
dentry = lookup_one_len (PRIVROOT_NAME, s->s_root,
strlen (PRIVROOT_NAME));
if (!IS_ERR (dentry)) {
if (!(mount_flags & MS_RDONLY) && !dentry->d_inode) {
struct inode *inode = dentry->d_parent->d_inode;
down (&inode->i_sem);
err = inode->i_op->mkdir (inode, dentry, 0700);
up (&inode->i_sem);
if (err) {
dput (dentry);
dentry = NULL;
}
if (dentry && dentry->d_inode)
reiserfs_warning (s, "Created %s on %s - reserved for "
"xattr storage.", PRIVROOT_NAME,
reiserfs_bdevname (inode->i_sb));
} else if (!dentry->d_inode) {
dput (dentry);
dentry = NULL;
}
} else
err = PTR_ERR (dentry);
if (!err && dentry) {
s->s_root->d_op = &xattr_lookup_poison_ops;
reiserfs_mark_inode_private (dentry->d_inode);
REISERFS_SB(s)->priv_root = dentry;
} else if (!(mount_flags & MS_RDONLY)) { /* xattrs are unavailable */
/* If we're read-only it just means that the dir hasn't been
* created. Not an error -- just no xattrs on the fs. We'll
* check again if we go read-write */
reiserfs_warning (s, "xattrs/ACLs enabled and couldn't "
"find/create .reiserfs_priv. Failing mount.");
err = -EOPNOTSUPP;
}
}
error:
/* This is only nonzero if there was an error initializing the xattr
* directory or if there is a condition where we don't support them. */
if (err) {
clear_bit (REISERFS_XATTRS, &(REISERFS_SB(s)->s_mount_opt));
clear_bit (REISERFS_XATTRS_USER, &(REISERFS_SB(s)->s_mount_opt));
clear_bit (REISERFS_POSIXACL, &(REISERFS_SB(s)->s_mount_opt));
}
/* The super_block MS_POSIXACL must mirror the (no)acl mount option. */
s->s_flags = s->s_flags & ~MS_POSIXACL;
if (reiserfs_posixacl (s))
s->s_flags |= MS_POSIXACL;
return err;
}
static int
__reiserfs_permission (struct inode *inode, int mask, struct nameidata *nd,
int need_lock)
{
umode_t mode = inode->i_mode;
if (mask & MAY_WRITE) {
/*
* Nobody gets write access to a read-only fs.
*/
if (IS_RDONLY(inode) &&
(S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)))
return -EROFS;
/*
* Nobody gets write access to an immutable file.
*/
if (IS_IMMUTABLE(inode))
return -EACCES;
}
/* We don't do permission checks on the internal objects.
* Permissions are determined by the "owning" object. */
if (is_reiserfs_priv_object (inode))
return 0;
if (current->fsuid == inode->i_uid) {
mode >>= 6;
#ifdef CONFIG_REISERFS_FS_POSIX_ACL
} else if (reiserfs_posixacl(inode->i_sb) &&
get_inode_sd_version (inode) != STAT_DATA_V1) {
struct posix_acl *acl;
/* ACL can't contain additional permissions if
the ACL_MASK entry is 0 */
if (!(mode & S_IRWXG))
goto check_groups;
if (need_lock) {
reiserfs_read_lock_xattr_i (inode);
reiserfs_read_lock_xattrs (inode->i_sb);
}
acl = reiserfs_get_acl (inode, ACL_TYPE_ACCESS);
if (need_lock) {
reiserfs_read_unlock_xattrs (inode->i_sb);
reiserfs_read_unlock_xattr_i (inode);
}
if (IS_ERR (acl)) {
if (PTR_ERR (acl) == -ENODATA)
goto check_groups;
return PTR_ERR (acl);
}
if (acl) {
int err = posix_acl_permission (inode, acl, mask);
posix_acl_release (acl);
if (err == -EACCES) {
goto check_capabilities;
}
return err;
} else {
goto check_groups;
}
#endif
} else {
check_groups:
if (in_group_p(inode->i_gid))
mode >>= 3;
}
/*
* If the DACs are ok we don't need any capability check.
*/
if (((mode & mask & (MAY_READ|MAY_WRITE|MAY_EXEC)) == mask))
return 0;
check_capabilities:
/*
* Read/write DACs are always overridable.
* Executable DACs are overridable if at least one exec bit is set.
*/
if (!(mask & MAY_EXEC) ||
(inode->i_mode & S_IXUGO) || S_ISDIR(inode->i_mode))
if (capable(CAP_DAC_OVERRIDE))
return 0;
/*
* Searching includes executable on directories, else just read.
*/
if (mask == MAY_READ || (S_ISDIR(inode->i_mode) && !(mask & MAY_WRITE)))
if (capable(CAP_DAC_READ_SEARCH))
return 0;
return -EACCES;
}
int
reiserfs_permission (struct inode *inode, int mask, struct nameidata *nd)
{
return __reiserfs_permission (inode, mask, nd, 1);
}
int
reiserfs_permission_locked (struct inode *inode, int mask, struct nameidata *nd)
{
return __reiserfs_permission (inode, mask, nd, 0);
}
