linux/fs/xfs/xfs_iops.c
Darrick J. Wong cab23a4233 xfs: hide private inodes from bulkstat and handle functions
We're about to start adding functionality that uses internal inodes that
are private to XFS.  What this means is that userspace should never be
able to access any information about these files, and should not be able
to open these files by handle.

To prevent users from ever finding the file or mis-interactions with the
security apparatus, set S_PRIVATE on the inode.  Don't allow bulkstat,
open-by-handle, or linking of S_PRIVATE files into the directory tree.
This should keep private inodes actually private.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-04-15 14:58:48 -07:00

1352 lines
34 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2000-2005 Silicon Graphics, Inc.
* All Rights Reserved.
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_inode.h"
#include "xfs_acl.h"
#include "xfs_quota.h"
#include "xfs_da_format.h"
#include "xfs_da_btree.h"
#include "xfs_attr.h"
#include "xfs_trans.h"
#include "xfs_trace.h"
#include "xfs_icache.h"
#include "xfs_symlink.h"
#include "xfs_dir2.h"
#include "xfs_iomap.h"
#include "xfs_error.h"
#include "xfs_ioctl.h"
#include "xfs_xattr.h"
#include "xfs_file.h"
#include <linux/posix_acl.h>
#include <linux/security.h>
#include <linux/iversion.h>
#include <linux/fiemap.h>
/*
* Directories have different lock order w.r.t. mmap_lock compared to regular
* files. This is due to readdir potentially triggering page faults on a user
* buffer inside filldir(), and this happens with the ilock on the directory
* held. For regular files, the lock order is the other way around - the
* mmap_lock is taken during the page fault, and then we lock the ilock to do
* block mapping. Hence we need a different class for the directory ilock so
* that lockdep can tell them apart.
*/
static struct lock_class_key xfs_nondir_ilock_class;
static struct lock_class_key xfs_dir_ilock_class;
static int
xfs_initxattrs(
struct inode *inode,
const struct xattr *xattr_array,
void *fs_info)
{
const struct xattr *xattr;
struct xfs_inode *ip = XFS_I(inode);
int error = 0;
for (xattr = xattr_array; xattr->name != NULL; xattr++) {
struct xfs_da_args args = {
.dp = ip,
.attr_filter = XFS_ATTR_SECURE,
.name = xattr->name,
.namelen = strlen(xattr->name),
.value = xattr->value,
.valuelen = xattr->value_len,
};
error = xfs_attr_change(&args);
if (error < 0)
break;
}
return error;
}
/*
* Hook in SELinux. This is not quite correct yet, what we really need
* here (as we do for default ACLs) is a mechanism by which creation of
* these attrs can be journalled at inode creation time (along with the
* inode, of course, such that log replay can't cause these to be lost).
*/
int
xfs_inode_init_security(
struct inode *inode,
struct inode *dir,
const struct qstr *qstr)
{
return security_inode_init_security(inode, dir, qstr,
&xfs_initxattrs, NULL);
}
static void
xfs_dentry_to_name(
struct xfs_name *namep,
struct dentry *dentry)
{
namep->name = dentry->d_name.name;
namep->len = dentry->d_name.len;
namep->type = XFS_DIR3_FT_UNKNOWN;
}
static int
xfs_dentry_mode_to_name(
struct xfs_name *namep,
struct dentry *dentry,
int mode)
{
namep->name = dentry->d_name.name;
namep->len = dentry->d_name.len;
namep->type = xfs_mode_to_ftype(mode);
if (unlikely(namep->type == XFS_DIR3_FT_UNKNOWN))
return -EFSCORRUPTED;
return 0;
}
STATIC void
xfs_cleanup_inode(
struct inode *dir,
struct inode *inode,
struct dentry *dentry)
{
struct xfs_name teardown;
/* Oh, the horror.
* If we can't add the ACL or we fail in
* xfs_inode_init_security we must back out.
* ENOSPC can hit here, among other things.
*/
xfs_dentry_to_name(&teardown, dentry);
xfs_remove(XFS_I(dir), &teardown, XFS_I(inode));
}
/*
* Check to see if we are likely to need an extended attribute to be added to
* the inode we are about to allocate. This allows the attribute fork to be
* created during the inode allocation, reducing the number of transactions we
* need to do in this fast path.
*
* The security checks are optimistic, but not guaranteed. The two LSMs that
* require xattrs to be added here (selinux and smack) are also the only two
* LSMs that add a sb->s_security structure to the superblock. Hence if security
* is enabled and sb->s_security is set, we have a pretty good idea that we are
* going to be asked to add a security xattr immediately after allocating the
* xfs inode and instantiating the VFS inode.
*/
static inline bool
xfs_create_need_xattr(
struct inode *dir,
struct posix_acl *default_acl,
struct posix_acl *acl)
{
if (acl)
return true;
if (default_acl)
return true;
#if IS_ENABLED(CONFIG_SECURITY)
if (dir->i_sb->s_security)
return true;
#endif
return false;
}
STATIC int
xfs_generic_create(
struct mnt_idmap *idmap,
struct inode *dir,
struct dentry *dentry,
umode_t mode,
dev_t rdev,
struct file *tmpfile) /* unnamed file */
{
struct inode *inode;
struct xfs_inode *ip = NULL;
struct posix_acl *default_acl, *acl;
struct xfs_name name;
int error;
/*
* Irix uses Missed'em'V split, but doesn't want to see
* the upper 5 bits of (14bit) major.
*/
if (S_ISCHR(mode) || S_ISBLK(mode)) {
if (unlikely(!sysv_valid_dev(rdev) || MAJOR(rdev) & ~0x1ff))
return -EINVAL;
} else {
rdev = 0;
}
error = posix_acl_create(dir, &mode, &default_acl, &acl);
if (error)
return error;
/* Verify mode is valid also for tmpfile case */
error = xfs_dentry_mode_to_name(&name, dentry, mode);
if (unlikely(error))
goto out_free_acl;
if (!tmpfile) {
error = xfs_create(idmap, XFS_I(dir), &name, mode, rdev,
xfs_create_need_xattr(dir, default_acl, acl),
&ip);
} else {
error = xfs_create_tmpfile(idmap, XFS_I(dir), mode, &ip);
}
if (unlikely(error))
goto out_free_acl;
inode = VFS_I(ip);
error = xfs_inode_init_security(inode, dir, &dentry->d_name);
if (unlikely(error))
goto out_cleanup_inode;
if (default_acl) {
error = __xfs_set_acl(inode, default_acl, ACL_TYPE_DEFAULT);
if (error)
goto out_cleanup_inode;
}
if (acl) {
error = __xfs_set_acl(inode, acl, ACL_TYPE_ACCESS);
if (error)
goto out_cleanup_inode;
}
xfs_setup_iops(ip);
if (tmpfile) {
/*
* The VFS requires that any inode fed to d_tmpfile must have
* nlink == 1 so that it can decrement the nlink in d_tmpfile.
* However, we created the temp file with nlink == 0 because
* we're not allowed to put an inode with nlink > 0 on the
* unlinked list. Therefore we have to set nlink to 1 so that
* d_tmpfile can immediately set it back to zero.
*/
set_nlink(inode, 1);
d_tmpfile(tmpfile, inode);
} else
d_instantiate(dentry, inode);
xfs_finish_inode_setup(ip);
out_free_acl:
posix_acl_release(default_acl);
posix_acl_release(acl);
return error;
out_cleanup_inode:
xfs_finish_inode_setup(ip);
if (!tmpfile)
xfs_cleanup_inode(dir, inode, dentry);
xfs_irele(ip);
goto out_free_acl;
}
STATIC int
xfs_vn_mknod(
struct mnt_idmap *idmap,
struct inode *dir,
struct dentry *dentry,
umode_t mode,
dev_t rdev)
{
return xfs_generic_create(idmap, dir, dentry, mode, rdev, NULL);
}
STATIC int
xfs_vn_create(
struct mnt_idmap *idmap,
struct inode *dir,
struct dentry *dentry,
umode_t mode,
bool flags)
{
return xfs_generic_create(idmap, dir, dentry, mode, 0, NULL);
}
STATIC int
xfs_vn_mkdir(
struct mnt_idmap *idmap,
struct inode *dir,
struct dentry *dentry,
umode_t mode)
{
return xfs_generic_create(idmap, dir, dentry, mode | S_IFDIR, 0, NULL);
}
STATIC struct dentry *
xfs_vn_lookup(
struct inode *dir,
struct dentry *dentry,
unsigned int flags)
{
struct inode *inode;
struct xfs_inode *cip;
struct xfs_name name;
int error;
if (dentry->d_name.len >= MAXNAMELEN)
return ERR_PTR(-ENAMETOOLONG);
xfs_dentry_to_name(&name, dentry);
error = xfs_lookup(XFS_I(dir), &name, &cip, NULL);
if (likely(!error))
inode = VFS_I(cip);
else if (likely(error == -ENOENT))
inode = NULL;
else
inode = ERR_PTR(error);
return d_splice_alias(inode, dentry);
}
STATIC struct dentry *
xfs_vn_ci_lookup(
struct inode *dir,
struct dentry *dentry,
unsigned int flags)
{
struct xfs_inode *ip;
struct xfs_name xname;
struct xfs_name ci_name;
struct qstr dname;
int error;
if (dentry->d_name.len >= MAXNAMELEN)
return ERR_PTR(-ENAMETOOLONG);
xfs_dentry_to_name(&xname, dentry);
error = xfs_lookup(XFS_I(dir), &xname, &ip, &ci_name);
if (unlikely(error)) {
if (unlikely(error != -ENOENT))
return ERR_PTR(error);
/*
* call d_add(dentry, NULL) here when d_drop_negative_children
* is called in xfs_vn_mknod (ie. allow negative dentries
* with CI filesystems).
*/
return NULL;
}
/* if exact match, just splice and exit */
if (!ci_name.name)
return d_splice_alias(VFS_I(ip), dentry);
/* else case-insensitive match... */
dname.name = ci_name.name;
dname.len = ci_name.len;
dentry = d_add_ci(dentry, VFS_I(ip), &dname);
kfree(ci_name.name);
return dentry;
}
STATIC int
xfs_vn_link(
struct dentry *old_dentry,
struct inode *dir,
struct dentry *dentry)
{
struct inode *inode = d_inode(old_dentry);
struct xfs_name name;
int error;
error = xfs_dentry_mode_to_name(&name, dentry, inode->i_mode);
if (unlikely(error))
return error;
if (IS_PRIVATE(inode))
return -EPERM;
error = xfs_link(XFS_I(dir), XFS_I(inode), &name);
if (unlikely(error))
return error;
ihold(inode);
d_instantiate(dentry, inode);
return 0;
}
STATIC int
xfs_vn_unlink(
struct inode *dir,
struct dentry *dentry)
{
struct xfs_name name;
int error;
xfs_dentry_to_name(&name, dentry);
error = xfs_remove(XFS_I(dir), &name, XFS_I(d_inode(dentry)));
if (error)
return error;
/*
* With unlink, the VFS makes the dentry "negative": no inode,
* but still hashed. This is incompatible with case-insensitive
* mode, so invalidate (unhash) the dentry in CI-mode.
*/
if (xfs_has_asciici(XFS_M(dir->i_sb)))
d_invalidate(dentry);
return 0;
}
STATIC int
xfs_vn_symlink(
struct mnt_idmap *idmap,
struct inode *dir,
struct dentry *dentry,
const char *symname)
{
struct inode *inode;
struct xfs_inode *cip = NULL;
struct xfs_name name;
int error;
umode_t mode;
mode = S_IFLNK |
(irix_symlink_mode ? 0777 & ~current_umask() : S_IRWXUGO);
error = xfs_dentry_mode_to_name(&name, dentry, mode);
if (unlikely(error))
goto out;
error = xfs_symlink(idmap, XFS_I(dir), &name, symname, mode, &cip);
if (unlikely(error))
goto out;
inode = VFS_I(cip);
error = xfs_inode_init_security(inode, dir, &dentry->d_name);
if (unlikely(error))
goto out_cleanup_inode;
xfs_setup_iops(cip);
d_instantiate(dentry, inode);
xfs_finish_inode_setup(cip);
return 0;
out_cleanup_inode:
xfs_finish_inode_setup(cip);
xfs_cleanup_inode(dir, inode, dentry);
xfs_irele(cip);
out:
return error;
}
STATIC int
xfs_vn_rename(
struct mnt_idmap *idmap,
struct inode *odir,
struct dentry *odentry,
struct inode *ndir,
struct dentry *ndentry,
unsigned int flags)
{
struct inode *new_inode = d_inode(ndentry);
int omode = 0;
int error;
struct xfs_name oname;
struct xfs_name nname;
if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
return -EINVAL;
/* if we are exchanging files, we need to set i_mode of both files */
if (flags & RENAME_EXCHANGE)
omode = d_inode(ndentry)->i_mode;
error = xfs_dentry_mode_to_name(&oname, odentry, omode);
if (omode && unlikely(error))
return error;
error = xfs_dentry_mode_to_name(&nname, ndentry,
d_inode(odentry)->i_mode);
if (unlikely(error))
return error;
return xfs_rename(idmap, XFS_I(odir), &oname,
XFS_I(d_inode(odentry)), XFS_I(ndir), &nname,
new_inode ? XFS_I(new_inode) : NULL, flags);
}
/*
* careful here - this function can get called recursively, so
* we need to be very careful about how much stack we use.
* uio is kmalloced for this reason...
*/
STATIC const char *
xfs_vn_get_link(
struct dentry *dentry,
struct inode *inode,
struct delayed_call *done)
{
char *link;
int error = -ENOMEM;
if (!dentry)
return ERR_PTR(-ECHILD);
link = kmalloc(XFS_SYMLINK_MAXLEN+1, GFP_KERNEL);
if (!link)
goto out_err;
error = xfs_readlink(XFS_I(d_inode(dentry)), link);
if (unlikely(error))
goto out_kfree;
set_delayed_call(done, kfree_link, link);
return link;
out_kfree:
kfree(link);
out_err:
return ERR_PTR(error);
}
static uint32_t
xfs_stat_blksize(
struct xfs_inode *ip)
{
struct xfs_mount *mp = ip->i_mount;
/*
* If the file blocks are being allocated from a realtime volume, then
* always return the realtime extent size.
*/
if (XFS_IS_REALTIME_INODE(ip))
return XFS_FSB_TO_B(mp, xfs_get_extsz_hint(ip));
/*
* Allow large block sizes to be reported to userspace programs if the
* "largeio" mount option is used.
*
* If compatibility mode is specified, simply return the basic unit of
* caching so that we don't get inefficient read/modify/write I/O from
* user apps. Otherwise....
*
* If the underlying volume is a stripe, then return the stripe width in
* bytes as the recommended I/O size. It is not a stripe and we've set a
* default buffered I/O size, return that, otherwise return the compat
* default.
*/
if (xfs_has_large_iosize(mp)) {
if (mp->m_swidth)
return XFS_FSB_TO_B(mp, mp->m_swidth);
if (xfs_has_allocsize(mp))
return 1U << mp->m_allocsize_log;
}
return PAGE_SIZE;
}
STATIC int
xfs_vn_getattr(
struct mnt_idmap *idmap,
const struct path *path,
struct kstat *stat,
u32 request_mask,
unsigned int query_flags)
{
struct inode *inode = d_inode(path->dentry);
struct xfs_inode *ip = XFS_I(inode);
struct xfs_mount *mp = ip->i_mount;
vfsuid_t vfsuid = i_uid_into_vfsuid(idmap, inode);
vfsgid_t vfsgid = i_gid_into_vfsgid(idmap, inode);
trace_xfs_getattr(ip);
if (xfs_is_shutdown(mp))
return -EIO;
stat->size = XFS_ISIZE(ip);
stat->dev = inode->i_sb->s_dev;
stat->mode = inode->i_mode;
stat->nlink = inode->i_nlink;
stat->uid = vfsuid_into_kuid(vfsuid);
stat->gid = vfsgid_into_kgid(vfsgid);
stat->ino = ip->i_ino;
stat->atime = inode_get_atime(inode);
stat->mtime = inode_get_mtime(inode);
stat->ctime = inode_get_ctime(inode);
stat->blocks = XFS_FSB_TO_BB(mp, ip->i_nblocks + ip->i_delayed_blks);
if (xfs_has_v3inodes(mp)) {
if (request_mask & STATX_BTIME) {
stat->result_mask |= STATX_BTIME;
stat->btime = ip->i_crtime;
}
}
if ((request_mask & STATX_CHANGE_COOKIE) && IS_I_VERSION(inode)) {
stat->change_cookie = inode_query_iversion(inode);
stat->result_mask |= STATX_CHANGE_COOKIE;
}
/*
* Note: If you add another clause to set an attribute flag, please
* update attributes_mask below.
*/
if (ip->i_diflags & XFS_DIFLAG_IMMUTABLE)
stat->attributes |= STATX_ATTR_IMMUTABLE;
if (ip->i_diflags & XFS_DIFLAG_APPEND)
stat->attributes |= STATX_ATTR_APPEND;
if (ip->i_diflags & XFS_DIFLAG_NODUMP)
stat->attributes |= STATX_ATTR_NODUMP;
stat->attributes_mask |= (STATX_ATTR_IMMUTABLE |
STATX_ATTR_APPEND |
STATX_ATTR_NODUMP);
switch (inode->i_mode & S_IFMT) {
case S_IFBLK:
case S_IFCHR:
stat->blksize = BLKDEV_IOSIZE;
stat->rdev = inode->i_rdev;
break;
case S_IFREG:
if (request_mask & STATX_DIOALIGN) {
struct xfs_buftarg *target = xfs_inode_buftarg(ip);
struct block_device *bdev = target->bt_bdev;
stat->result_mask |= STATX_DIOALIGN;
stat->dio_mem_align = bdev_dma_alignment(bdev) + 1;
stat->dio_offset_align = bdev_logical_block_size(bdev);
}
fallthrough;
default:
stat->blksize = xfs_stat_blksize(ip);
stat->rdev = 0;
break;
}
return 0;
}
static int
xfs_vn_change_ok(
struct mnt_idmap *idmap,
struct dentry *dentry,
struct iattr *iattr)
{
struct xfs_mount *mp = XFS_I(d_inode(dentry))->i_mount;
if (xfs_is_readonly(mp))
return -EROFS;
if (xfs_is_shutdown(mp))
return -EIO;
return setattr_prepare(idmap, dentry, iattr);
}
/*
* Set non-size attributes of an inode.
*
* Caution: The caller of this function is responsible for calling
* setattr_prepare() or otherwise verifying the change is fine.
*/
static int
xfs_setattr_nonsize(
struct mnt_idmap *idmap,
struct dentry *dentry,
struct xfs_inode *ip,
struct iattr *iattr)
{
xfs_mount_t *mp = ip->i_mount;
struct inode *inode = VFS_I(ip);
int mask = iattr->ia_valid;
xfs_trans_t *tp;
int error;
kuid_t uid = GLOBAL_ROOT_UID;
kgid_t gid = GLOBAL_ROOT_GID;
struct xfs_dquot *udqp = NULL, *gdqp = NULL;
struct xfs_dquot *old_udqp = NULL, *old_gdqp = NULL;
ASSERT((mask & ATTR_SIZE) == 0);
/*
* If disk quotas is on, we make sure that the dquots do exist on disk,
* before we start any other transactions. Trying to do this later
* is messy. We don't care to take a readlock to look at the ids
* in inode here, because we can't hold it across the trans_reserve.
* If the IDs do change before we take the ilock, we're covered
* because the i_*dquot fields will get updated anyway.
*/
if (XFS_IS_QUOTA_ON(mp) && (mask & (ATTR_UID|ATTR_GID))) {
uint qflags = 0;
if ((mask & ATTR_UID) && XFS_IS_UQUOTA_ON(mp)) {
uid = from_vfsuid(idmap, i_user_ns(inode),
iattr->ia_vfsuid);
qflags |= XFS_QMOPT_UQUOTA;
} else {
uid = inode->i_uid;
}
if ((mask & ATTR_GID) && XFS_IS_GQUOTA_ON(mp)) {
gid = from_vfsgid(idmap, i_user_ns(inode),
iattr->ia_vfsgid);
qflags |= XFS_QMOPT_GQUOTA;
} else {
gid = inode->i_gid;
}
/*
* We take a reference when we initialize udqp and gdqp,
* so it is important that we never blindly double trip on
* the same variable. See xfs_create() for an example.
*/
ASSERT(udqp == NULL);
ASSERT(gdqp == NULL);
error = xfs_qm_vop_dqalloc(ip, uid, gid, ip->i_projid,
qflags, &udqp, &gdqp, NULL);
if (error)
return error;
}
error = xfs_trans_alloc_ichange(ip, udqp, gdqp, NULL,
has_capability_noaudit(current, CAP_FOWNER), &tp);
if (error)
goto out_dqrele;
/*
* Register quota modifications in the transaction. Must be the owner
* or privileged. These IDs could have changed since we last looked at
* them. But, we're assured that if the ownership did change while we
* didn't have the inode locked, inode's dquot(s) would have changed
* also.
*/
if (XFS_IS_UQUOTA_ON(mp) &&
i_uid_needs_update(idmap, iattr, inode)) {
ASSERT(udqp);
old_udqp = xfs_qm_vop_chown(tp, ip, &ip->i_udquot, udqp);
}
if (XFS_IS_GQUOTA_ON(mp) &&
i_gid_needs_update(idmap, iattr, inode)) {
ASSERT(xfs_has_pquotino(mp) || !XFS_IS_PQUOTA_ON(mp));
ASSERT(gdqp);
old_gdqp = xfs_qm_vop_chown(tp, ip, &ip->i_gdquot, gdqp);
}
setattr_copy(idmap, inode, iattr);
xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
XFS_STATS_INC(mp, xs_ig_attrchg);
if (xfs_has_wsync(mp))
xfs_trans_set_sync(tp);
error = xfs_trans_commit(tp);
/*
* Release any dquot(s) the inode had kept before chown.
*/
xfs_qm_dqrele(old_udqp);
xfs_qm_dqrele(old_gdqp);
xfs_qm_dqrele(udqp);
xfs_qm_dqrele(gdqp);
if (error)
return error;
/*
* XXX(hch): Updating the ACL entries is not atomic vs the i_mode
* update. We could avoid this with linked transactions
* and passing down the transaction pointer all the way
* to attr_set. No previous user of the generic
* Posix ACL code seems to care about this issue either.
*/
if (mask & ATTR_MODE) {
error = posix_acl_chmod(idmap, dentry, inode->i_mode);
if (error)
return error;
}
return 0;
out_dqrele:
xfs_qm_dqrele(udqp);
xfs_qm_dqrele(gdqp);
return error;
}
/*
* Truncate file. Must have write permission and not be a directory.
*
* Caution: The caller of this function is responsible for calling
* setattr_prepare() or otherwise verifying the change is fine.
*/
STATIC int
xfs_setattr_size(
struct mnt_idmap *idmap,
struct dentry *dentry,
struct xfs_inode *ip,
struct iattr *iattr)
{
struct xfs_mount *mp = ip->i_mount;
struct inode *inode = VFS_I(ip);
xfs_off_t oldsize, newsize;
struct xfs_trans *tp;
int error;
uint lock_flags = 0;
bool did_zeroing = false;
xfs_assert_ilocked(ip, XFS_IOLOCK_EXCL | XFS_MMAPLOCK_EXCL);
ASSERT(S_ISREG(inode->i_mode));
ASSERT((iattr->ia_valid & (ATTR_UID|ATTR_GID|ATTR_ATIME|ATTR_ATIME_SET|
ATTR_MTIME_SET|ATTR_TIMES_SET)) == 0);
oldsize = inode->i_size;
newsize = iattr->ia_size;
/*
* Short circuit the truncate case for zero length files.
*/
if (newsize == 0 && oldsize == 0 && ip->i_df.if_nextents == 0) {
if (!(iattr->ia_valid & (ATTR_CTIME|ATTR_MTIME)))
return 0;
/*
* Use the regular setattr path to update the timestamps.
*/
iattr->ia_valid &= ~ATTR_SIZE;
return xfs_setattr_nonsize(idmap, dentry, ip, iattr);
}
/*
* Make sure that the dquots are attached to the inode.
*/
error = xfs_qm_dqattach(ip);
if (error)
return error;
/*
* Wait for all direct I/O to complete.
*/
inode_dio_wait(inode);
/*
* File data changes must be complete before we start the transaction to
* modify the inode. This needs to be done before joining the inode to
* the transaction because the inode cannot be unlocked once it is a
* part of the transaction.
*
* Start with zeroing any data beyond EOF that we may expose on file
* extension, or zeroing out the rest of the block on a downward
* truncate.
*/
if (newsize > oldsize) {
trace_xfs_zero_eof(ip, oldsize, newsize - oldsize);
error = xfs_zero_range(ip, oldsize, newsize - oldsize,
&did_zeroing);
} else {
/*
* iomap won't detect a dirty page over an unwritten block (or a
* cow block over a hole) and subsequently skips zeroing the
* newly post-EOF portion of the page. Flush the new EOF to
* convert the block before the pagecache truncate.
*/
error = filemap_write_and_wait_range(inode->i_mapping, newsize,
newsize);
if (error)
return error;
error = xfs_truncate_page(ip, newsize, &did_zeroing);
}
if (error)
return error;
/*
* We've already locked out new page faults, so now we can safely remove
* pages from the page cache knowing they won't get refaulted until we
* drop the XFS_MMAP_EXCL lock after the extent manipulations are
* complete. The truncate_setsize() call also cleans partial EOF page
* PTEs on extending truncates and hence ensures sub-page block size
* filesystems are correctly handled, too.
*
* We have to do all the page cache truncate work outside the
* transaction context as the "lock" order is page lock->log space
* reservation as defined by extent allocation in the writeback path.
* Hence a truncate can fail with ENOMEM from xfs_trans_alloc(), but
* having already truncated the in-memory version of the file (i.e. made
* user visible changes). There's not much we can do about this, except
* to hope that the caller sees ENOMEM and retries the truncate
* operation.
*
* And we update in-core i_size and truncate page cache beyond newsize
* before writeback the [i_disk_size, newsize] range, so we're
* guaranteed not to write stale data past the new EOF on truncate down.
*/
truncate_setsize(inode, newsize);
/*
* We are going to log the inode size change in this transaction so
* any previous writes that are beyond the on disk EOF and the new
* EOF that have not been written out need to be written here. If we
* do not write the data out, we expose ourselves to the null files
* problem. Note that this includes any block zeroing we did above;
* otherwise those blocks may not be zeroed after a crash.
*/
if (did_zeroing ||
(newsize > ip->i_disk_size && oldsize != ip->i_disk_size)) {
error = filemap_write_and_wait_range(VFS_I(ip)->i_mapping,
ip->i_disk_size, newsize - 1);
if (error)
return error;
}
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate, 0, 0, 0, &tp);
if (error)
return error;
lock_flags |= XFS_ILOCK_EXCL;
xfs_ilock(ip, XFS_ILOCK_EXCL);
xfs_trans_ijoin(tp, ip, 0);
/*
* Only change the c/mtime if we are changing the size or we are
* explicitly asked to change it. This handles the semantic difference
* between truncate() and ftruncate() as implemented in the VFS.
*
* The regular truncate() case without ATTR_CTIME and ATTR_MTIME is a
* special case where we need to update the times despite not having
* these flags set. For all other operations the VFS set these flags
* explicitly if it wants a timestamp update.
*/
if (newsize != oldsize &&
!(iattr->ia_valid & (ATTR_CTIME | ATTR_MTIME))) {
iattr->ia_ctime = iattr->ia_mtime =
current_time(inode);
iattr->ia_valid |= ATTR_CTIME | ATTR_MTIME;
}
/*
* The first thing we do is set the size to new_size permanently on
* disk. This way we don't have to worry about anyone ever being able
* to look at the data being freed even in the face of a crash.
* What we're getting around here is the case where we free a block, it
* is allocated to another file, it is written to, and then we crash.
* If the new data gets written to the file but the log buffers
* containing the free and reallocation don't, then we'd end up with
* garbage in the blocks being freed. As long as we make the new size
* permanent before actually freeing any blocks it doesn't matter if
* they get written to.
*/
ip->i_disk_size = newsize;
xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
if (newsize <= oldsize) {
error = xfs_itruncate_extents(&tp, ip, XFS_DATA_FORK, newsize);
if (error)
goto out_trans_cancel;
/*
* Truncated "down", so we're removing references to old data
* here - if we delay flushing for a long time, we expose
* ourselves unduly to the notorious NULL files problem. So,
* we mark this inode and flush it when the file is closed,
* and do not wait the usual (long) time for writeout.
*/
xfs_iflags_set(ip, XFS_ITRUNCATED);
/* A truncate down always removes post-EOF blocks. */
xfs_inode_clear_eofblocks_tag(ip);
}
ASSERT(!(iattr->ia_valid & (ATTR_UID | ATTR_GID)));
setattr_copy(idmap, inode, iattr);
xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
XFS_STATS_INC(mp, xs_ig_attrchg);
if (xfs_has_wsync(mp))
xfs_trans_set_sync(tp);
error = xfs_trans_commit(tp);
out_unlock:
if (lock_flags)
xfs_iunlock(ip, lock_flags);
return error;
out_trans_cancel:
xfs_trans_cancel(tp);
goto out_unlock;
}
int
xfs_vn_setattr_size(
struct mnt_idmap *idmap,
struct dentry *dentry,
struct iattr *iattr)
{
struct xfs_inode *ip = XFS_I(d_inode(dentry));
int error;
trace_xfs_setattr(ip);
error = xfs_vn_change_ok(idmap, dentry, iattr);
if (error)
return error;
return xfs_setattr_size(idmap, dentry, ip, iattr);
}
STATIC int
xfs_vn_setattr(
struct mnt_idmap *idmap,
struct dentry *dentry,
struct iattr *iattr)
{
struct inode *inode = d_inode(dentry);
struct xfs_inode *ip = XFS_I(inode);
int error;
if (iattr->ia_valid & ATTR_SIZE) {
uint iolock;
xfs_ilock(ip, XFS_MMAPLOCK_EXCL);
iolock = XFS_IOLOCK_EXCL | XFS_MMAPLOCK_EXCL;
error = xfs_break_layouts(inode, &iolock, BREAK_UNMAP);
if (error) {
xfs_iunlock(ip, XFS_MMAPLOCK_EXCL);
return error;
}
error = xfs_vn_setattr_size(idmap, dentry, iattr);
xfs_iunlock(ip, XFS_MMAPLOCK_EXCL);
} else {
trace_xfs_setattr(ip);
error = xfs_vn_change_ok(idmap, dentry, iattr);
if (!error)
error = xfs_setattr_nonsize(idmap, dentry, ip, iattr);
}
return error;
}
STATIC int
xfs_vn_update_time(
struct inode *inode,
int flags)
{
struct xfs_inode *ip = XFS_I(inode);
struct xfs_mount *mp = ip->i_mount;
int log_flags = XFS_ILOG_TIMESTAMP;
struct xfs_trans *tp;
int error;
struct timespec64 now;
trace_xfs_update_time(ip);
if (inode->i_sb->s_flags & SB_LAZYTIME) {
if (!((flags & S_VERSION) &&
inode_maybe_inc_iversion(inode, false))) {
generic_update_time(inode, flags);
return 0;
}
/* Capture the iversion update that just occurred */
log_flags |= XFS_ILOG_CORE;
}
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_fsyncts, 0, 0, 0, &tp);
if (error)
return error;
xfs_ilock(ip, XFS_ILOCK_EXCL);
if (flags & (S_CTIME|S_MTIME))
now = inode_set_ctime_current(inode);
else
now = current_time(inode);
if (flags & S_MTIME)
inode_set_mtime_to_ts(inode, now);
if (flags & S_ATIME)
inode_set_atime_to_ts(inode, now);
xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
xfs_trans_log_inode(tp, ip, log_flags);
return xfs_trans_commit(tp);
}
STATIC int
xfs_vn_fiemap(
struct inode *inode,
struct fiemap_extent_info *fieinfo,
u64 start,
u64 length)
{
int error;
xfs_ilock(XFS_I(inode), XFS_IOLOCK_SHARED);
if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
fieinfo->fi_flags &= ~FIEMAP_FLAG_XATTR;
error = iomap_fiemap(inode, fieinfo, start, length,
&xfs_xattr_iomap_ops);
} else {
error = iomap_fiemap(inode, fieinfo, start, length,
&xfs_read_iomap_ops);
}
xfs_iunlock(XFS_I(inode), XFS_IOLOCK_SHARED);
return error;
}
STATIC int
xfs_vn_tmpfile(
struct mnt_idmap *idmap,
struct inode *dir,
struct file *file,
umode_t mode)
{
int err = xfs_generic_create(idmap, dir, file->f_path.dentry, mode, 0, file);
return finish_open_simple(file, err);
}
static const struct inode_operations xfs_inode_operations = {
.get_inode_acl = xfs_get_acl,
.set_acl = xfs_set_acl,
.getattr = xfs_vn_getattr,
.setattr = xfs_vn_setattr,
.listxattr = xfs_vn_listxattr,
.fiemap = xfs_vn_fiemap,
.update_time = xfs_vn_update_time,
.fileattr_get = xfs_fileattr_get,
.fileattr_set = xfs_fileattr_set,
};
static const struct inode_operations xfs_dir_inode_operations = {
.create = xfs_vn_create,
.lookup = xfs_vn_lookup,
.link = xfs_vn_link,
.unlink = xfs_vn_unlink,
.symlink = xfs_vn_symlink,
.mkdir = xfs_vn_mkdir,
/*
* Yes, XFS uses the same method for rmdir and unlink.
*
* There are some subtile differences deeper in the code,
* but we use S_ISDIR to check for those.
*/
.rmdir = xfs_vn_unlink,
.mknod = xfs_vn_mknod,
.rename = xfs_vn_rename,
.get_inode_acl = xfs_get_acl,
.set_acl = xfs_set_acl,
.getattr = xfs_vn_getattr,
.setattr = xfs_vn_setattr,
.listxattr = xfs_vn_listxattr,
.update_time = xfs_vn_update_time,
.tmpfile = xfs_vn_tmpfile,
.fileattr_get = xfs_fileattr_get,
.fileattr_set = xfs_fileattr_set,
};
static const struct inode_operations xfs_dir_ci_inode_operations = {
.create = xfs_vn_create,
.lookup = xfs_vn_ci_lookup,
.link = xfs_vn_link,
.unlink = xfs_vn_unlink,
.symlink = xfs_vn_symlink,
.mkdir = xfs_vn_mkdir,
/*
* Yes, XFS uses the same method for rmdir and unlink.
*
* There are some subtile differences deeper in the code,
* but we use S_ISDIR to check for those.
*/
.rmdir = xfs_vn_unlink,
.mknod = xfs_vn_mknod,
.rename = xfs_vn_rename,
.get_inode_acl = xfs_get_acl,
.set_acl = xfs_set_acl,
.getattr = xfs_vn_getattr,
.setattr = xfs_vn_setattr,
.listxattr = xfs_vn_listxattr,
.update_time = xfs_vn_update_time,
.tmpfile = xfs_vn_tmpfile,
.fileattr_get = xfs_fileattr_get,
.fileattr_set = xfs_fileattr_set,
};
static const struct inode_operations xfs_symlink_inode_operations = {
.get_link = xfs_vn_get_link,
.getattr = xfs_vn_getattr,
.setattr = xfs_vn_setattr,
.listxattr = xfs_vn_listxattr,
.update_time = xfs_vn_update_time,
};
/* Figure out if this file actually supports DAX. */
static bool
xfs_inode_supports_dax(
struct xfs_inode *ip)
{
struct xfs_mount *mp = ip->i_mount;
/* Only supported on regular files. */
if (!S_ISREG(VFS_I(ip)->i_mode))
return false;
/* Block size must match page size */
if (mp->m_sb.sb_blocksize != PAGE_SIZE)
return false;
/* Device has to support DAX too. */
return xfs_inode_buftarg(ip)->bt_daxdev != NULL;
}
static bool
xfs_inode_should_enable_dax(
struct xfs_inode *ip)
{
if (!IS_ENABLED(CONFIG_FS_DAX))
return false;
if (xfs_has_dax_never(ip->i_mount))
return false;
if (!xfs_inode_supports_dax(ip))
return false;
if (xfs_has_dax_always(ip->i_mount))
return true;
if (ip->i_diflags2 & XFS_DIFLAG2_DAX)
return true;
return false;
}
void
xfs_diflags_to_iflags(
struct xfs_inode *ip,
bool init)
{
struct inode *inode = VFS_I(ip);
unsigned int xflags = xfs_ip2xflags(ip);
unsigned int flags = 0;
ASSERT(!(IS_DAX(inode) && init));
if (xflags & FS_XFLAG_IMMUTABLE)
flags |= S_IMMUTABLE;
if (xflags & FS_XFLAG_APPEND)
flags |= S_APPEND;
if (xflags & FS_XFLAG_SYNC)
flags |= S_SYNC;
if (xflags & FS_XFLAG_NOATIME)
flags |= S_NOATIME;
if (init && xfs_inode_should_enable_dax(ip))
flags |= S_DAX;
/*
* S_DAX can only be set during inode initialization and is never set by
* the VFS, so we cannot mask off S_DAX in i_flags.
*/
inode->i_flags &= ~(S_IMMUTABLE | S_APPEND | S_SYNC | S_NOATIME);
inode->i_flags |= flags;
}
/*
* Initialize the Linux inode.
*
* When reading existing inodes from disk this is called directly from xfs_iget,
* when creating a new inode it is called from xfs_init_new_inode after setting
* up the inode. These callers have different criteria for clearing XFS_INEW, so
* leave it up to the caller to deal with unlocking the inode appropriately.
*/
void
xfs_setup_inode(
struct xfs_inode *ip)
{
struct inode *inode = &ip->i_vnode;
gfp_t gfp_mask;
inode->i_ino = ip->i_ino;
inode->i_state |= I_NEW;
inode_sb_list_add(inode);
/* make the inode look hashed for the writeback code */
inode_fake_hash(inode);
i_size_write(inode, ip->i_disk_size);
xfs_diflags_to_iflags(ip, true);
if (S_ISDIR(inode->i_mode)) {
/*
* We set the i_rwsem class here to avoid potential races with
* lockdep_annotate_inode_mutex_key() reinitialising the lock
* after a filehandle lookup has already found the inode in
* cache before it has been unlocked via unlock_new_inode().
*/
lockdep_set_class(&inode->i_rwsem,
&inode->i_sb->s_type->i_mutex_dir_key);
lockdep_set_class(&ip->i_lock, &xfs_dir_ilock_class);
} else {
lockdep_set_class(&ip->i_lock, &xfs_nondir_ilock_class);
}
/*
* Ensure all page cache allocations are done from GFP_NOFS context to
* prevent direct reclaim recursion back into the filesystem and blowing
* stacks or deadlocking.
*/
gfp_mask = mapping_gfp_mask(inode->i_mapping);
mapping_set_gfp_mask(inode->i_mapping, (gfp_mask & ~(__GFP_FS)));
/*
* For real-time inodes update the stable write flags to that of the RT
* device instead of the data device.
*/
if (S_ISREG(inode->i_mode) && XFS_IS_REALTIME_INODE(ip))
xfs_update_stable_writes(ip);
/*
* If there is no attribute fork no ACL can exist on this inode,
* and it can't have any file capabilities attached to it either.
*/
if (!xfs_inode_has_attr_fork(ip)) {
inode_has_no_xattr(inode);
cache_no_acl(inode);
}
}
void
xfs_setup_iops(
struct xfs_inode *ip)
{
struct inode *inode = &ip->i_vnode;
switch (inode->i_mode & S_IFMT) {
case S_IFREG:
inode->i_op = &xfs_inode_operations;
inode->i_fop = &xfs_file_operations;
if (IS_DAX(inode))
inode->i_mapping->a_ops = &xfs_dax_aops;
else
inode->i_mapping->a_ops = &xfs_address_space_operations;
break;
case S_IFDIR:
if (xfs_has_asciici(XFS_M(inode->i_sb)))
inode->i_op = &xfs_dir_ci_inode_operations;
else
inode->i_op = &xfs_dir_inode_operations;
inode->i_fop = &xfs_dir_file_operations;
break;
case S_IFLNK:
inode->i_op = &xfs_symlink_inode_operations;
break;
default:
inode->i_op = &xfs_inode_operations;
init_special_inode(inode, inode->i_mode, inode->i_rdev);
break;
}
}