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fuse update for 6.9 

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Merge tag 'fuse-update-6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse

Pull fuse updates from Miklos Szeredi:

 - Add passthrough mode for regular file I/O.

   This allows performing read and write (also via memory maps) on a
   backing file without incurring the overhead of roundtrips to
   userspace. For now this is only allowed to privileged servers, but
   this limitation will go away in the future (Amir Goldstein)

 - Fix interaction of direct I/O mode with memory maps (Bernd Schubert)

 - Export filesystem tags through sysfs for virtiofs (Stefan Hajnoczi)

 - Allow resending queued requests for server crash recovery (Zhao Chen)

 - Misc fixes and cleanups

* tag 'fuse-update-6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse: (38 commits)
  fuse: get rid of ff->readdir.lock
  fuse: remove unneeded lock which protecting update of congestion_threshold
  fuse: Fix missing FOLL_PIN for direct-io
  fuse: remove an unnecessary if statement
  fuse: Track process write operations in both direct and writethrough modes
  fuse: Use the high bit of request ID for indicating resend requests
  fuse: Introduce a new notification type for resend pending requests
  fuse: add support for explicit export disabling
  fuse: __kuid_val/__kgid_val helpers in fuse_fill_attr_from_inode()
  fuse: fix typo for fuse_permission comment
  fuse: Convert fuse_writepage_locked to take a folio
  fuse: Remove fuse_writepage
  virtio_fs: remove duplicate check if queue is broken
  fuse: use FUSE_ROOT_ID in fuse_get_root_inode()
  fuse: don't unhash root
  fuse: fix root lookup with nonzero generation
  fuse: replace remaining make_bad_inode() with fuse_make_bad()
  virtiofs: drop __exit from virtio_fs_sysfs_exit()
  fuse: implement passthrough for mmap
  fuse: implement splice read/write passthrough
  ...
This commit is contained in:
Linus Torvalds 2024-03-15 09:47:14 -07:00
parent 68bf6bfdcf cdf6ac2a03
commit 6ce8b2ce0d
14 changed files with 1422 additions and 277 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
Documentation/ABI/testing/sysfs-fs-virtiofs Normal file
View File

@ -0,0 +1,11 @@
What: /sys/fs/virtiofs/<n>/tag
Date: Feb 2024
Contact: virtio-fs@lists.linux.dev
Description:
[RO] The mount "tag" that can be used to mount this filesystem.
What: /sys/fs/virtiofs/<n>/device
Date: Feb 2024
Contact: virtio-fs@lists.linux.dev
Description:
Symlink to the virtio device that exports this filesystem.

11
fs/fuse/Kconfig
View File

@ -52,3 +52,14 @@ config FUSE_DAX
If you want to allow mounting a Virtio Filesystem with the "dax"
option, answer Y.
config FUSE_PASSTHROUGH
bool "FUSE passthrough operations support"
default y
depends on FUSE_FS
select FS_STACK
help
This allows bypassing FUSE server by mapping specific FUSE operations
to be performed directly on a backing file.
If you want to allow passthrough operations, answer Y.

2
fs/fuse/Makefile
View File

@ -8,6 +8,8 @@ obj-$(CONFIG_CUSE) += cuse.o
obj-$(CONFIG_VIRTIO_FS) += virtiofs.o
fuse-y := dev.o dir.o file.o inode.o control.o xattr.o acl.o readdir.o ioctl.o
fuse-y += iomode.o
fuse-$(CONFIG_FUSE_DAX) += dax.o
fuse-$(CONFIG_FUSE_PASSTHROUGH) += passthrough.o
virtiofs-y := virtio_fs.o

6
fs/fuse/control.c
View File

@ -174,11 +174,7 @@ static ssize_t fuse_conn_congestion_threshold_write(struct file *file,
if (!fc)
goto out;
down_read(&fc->killsb);
spin_lock(&fc->bg_lock);
fc->congestion_threshold = val;
spin_unlock(&fc->bg_lock);
up_read(&fc->killsb);
WRITE_ONCE(fc->congestion_threshold, val);
fuse_conn_put(fc);
out:
return ret;

154
fs/fuse/dev.c
View File

@ -1775,6 +1775,61 @@ copy_finish:
return err;
}
/*
* Resending all processing queue requests.
*
* During a FUSE daemon panics and failover, it is possible for some inflight
* requests to be lost and never returned. As a result, applications awaiting
* replies would become stuck forever. To address this, we can use notification
* to trigger resending of these pending requests to the FUSE daemon, ensuring
* they are properly processed again.
*
* Please note that this strategy is applicable only to idempotent requests or
* if the FUSE daemon takes careful measures to avoid processing duplicated
* non-idempotent requests.
*/
static void fuse_resend(struct fuse_conn *fc)
{
struct fuse_dev *fud;
struct fuse_req *req, *next;
struct fuse_iqueue *fiq = &fc->iq;
LIST_HEAD(to_queue);
unsigned int i;
spin_lock(&fc->lock);
if (!fc->connected) {
spin_unlock(&fc->lock);
return;
}
list_for_each_entry(fud, &fc->devices, entry) {
struct fuse_pqueue *fpq = &fud->pq;
spin_lock(&fpq->lock);
for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
list_splice_tail_init(&fpq->processing[i], &to_queue);
spin_unlock(&fpq->lock);
}
spin_unlock(&fc->lock);
list_for_each_entry_safe(req, next, &to_queue, list) {
__set_bit(FR_PENDING, &req->flags);
/* mark the request as resend request */
req->in.h.unique |= FUSE_UNIQUE_RESEND;
}
spin_lock(&fiq->lock);
/* iq and pq requests are both oldest to newest */
list_splice(&to_queue, &fiq->pending);
fiq->ops->wake_pending_and_unlock(fiq);
}
static int fuse_notify_resend(struct fuse_conn *fc)
{
fuse_resend(fc);
return 0;
}
static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
unsigned int size, struct fuse_copy_state *cs)
{
@ -1800,6 +1855,9 @@ static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
case FUSE_NOTIFY_DELETE:
return fuse_notify_delete(fc, size, cs);
case FUSE_NOTIFY_RESEND:
return fuse_notify_resend(fc);
default:
fuse_copy_finish(cs);
return -EINVAL;
@ -2251,43 +2309,91 @@ static int fuse_device_clone(struct fuse_conn *fc, struct file *new)
return 0;
}
static long fuse_dev_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
static long fuse_dev_ioctl_clone(struct file *file, __u32 __user *argp)
{
int res;
int oldfd;
struct fuse_dev *fud = NULL;
struct fd f;
if (get_user(oldfd, argp))
return -EFAULT;
f = fdget(oldfd);
if (!f.file)
return -EINVAL;
/*
* Check against file->f_op because CUSE
* uses the same ioctl handler.
*/
if (f.file->f_op == file->f_op)
fud = fuse_get_dev(f.file);
res = -EINVAL;
if (fud) {
mutex_lock(&fuse_mutex);
res = fuse_device_clone(fud->fc, file);
mutex_unlock(&fuse_mutex);
}
fdput(f);
return res;
}
static long fuse_dev_ioctl_backing_open(struct file *file,
struct fuse_backing_map __user *argp)
{
struct fuse_dev *fud = fuse_get_dev(file);
struct fuse_backing_map map;
if (!fud)
return -EPERM;
if (!IS_ENABLED(CONFIG_FUSE_PASSTHROUGH))
return -EOPNOTSUPP;
if (copy_from_user(&map, argp, sizeof(map)))
return -EFAULT;
return fuse_backing_open(fud->fc, &map);
}
static long fuse_dev_ioctl_backing_close(struct file *file, __u32 __user *argp)
{
struct fuse_dev *fud = fuse_get_dev(file);
int backing_id;
if (!fud)
return -EPERM;
if (!IS_ENABLED(CONFIG_FUSE_PASSTHROUGH))
return -EOPNOTSUPP;
if (get_user(backing_id, argp))
return -EFAULT;
return fuse_backing_close(fud->fc, backing_id);
}
static long fuse_dev_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
void __user *argp = (void __user *)arg;
switch (cmd) {
case FUSE_DEV_IOC_CLONE:
if (get_user(oldfd, (__u32 __user *)arg))
return -EFAULT;
return fuse_dev_ioctl_clone(file, argp);
f = fdget(oldfd);
if (!f.file)
return -EINVAL;
case FUSE_DEV_IOC_BACKING_OPEN:
return fuse_dev_ioctl_backing_open(file, argp);
/*
* Check against file->f_op because CUSE
* uses the same ioctl handler.
*/
if (f.file->f_op == file->f_op)
fud = fuse_get_dev(f.file);
case FUSE_DEV_IOC_BACKING_CLOSE:
return fuse_dev_ioctl_backing_close(file, argp);
res = -EINVAL;
if (fud) {
mutex_lock(&fuse_mutex);
res = fuse_device_clone(fud->fc, file);
mutex_unlock(&fuse_mutex);
}
fdput(f);
break;
default:
res = -ENOTTY;
break;
return -ENOTTY;
}
return res;
}
const struct file_operations fuse_dev_operations = {

55
fs/fuse/dir.c
View File

@ -391,6 +391,10 @@ int fuse_lookup_name(struct super_block *sb, u64 nodeid, const struct qstr *name
err = -EIO;
if (fuse_invalid_attr(&outarg->attr))
goto out_put_forget;
if (outarg->nodeid == FUSE_ROOT_ID && outarg->generation != 0) {
pr_warn_once("root generation should be zero\n");
outarg->generation = 0;
}
*inode = fuse_iget(sb, outarg->nodeid, outarg->generation,
&outarg->attr, ATTR_TIMEOUT(outarg),
@ -615,7 +619,7 @@ static int fuse_create_open(struct inode *dir, struct dentry *entry,
FUSE_ARGS(args);
struct fuse_forget_link *forget;
struct fuse_create_in inarg;
struct fuse_open_out outopen;
struct fuse_open_out *outopenp;
struct fuse_entry_out outentry;
struct fuse_inode *fi;
struct fuse_file *ff;
@ -630,7 +634,7 @@ static int fuse_create_open(struct inode *dir, struct dentry *entry,
goto out_err;
err = -ENOMEM;
ff = fuse_file_alloc(fm);
ff = fuse_file_alloc(fm, true);
if (!ff)
goto out_put_forget_req;
@ -659,8 +663,10 @@ static int fuse_create_open(struct inode *dir, struct dentry *entry,
args.out_numargs = 2;
args.out_args[0].size = sizeof(outentry);
args.out_args[0].value = &outentry;
args.out_args[1].size = sizeof(outopen);
args.out_args[1].value = &outopen;
/* Store outarg for fuse_finish_open() */
outopenp = &ff->args->open_outarg;
args.out_args[1].size = sizeof(*outopenp);
args.out_args[1].value = outopenp;
err = get_create_ext(&args, dir, entry, mode);
if (err)
@ -676,9 +682,9 @@ static int fuse_create_open(struct inode *dir, struct dentry *entry,
fuse_invalid_attr(&outentry.attr))
goto out_free_ff;
ff->fh = outopen.fh;
ff->fh = outopenp->fh;
ff->nodeid = outentry.nodeid;
ff->open_flags = outopen.open_flags;
ff->open_flags = outopenp->open_flags;
inode = fuse_iget(dir->i_sb, outentry.nodeid, outentry.generation,
&outentry.attr, ATTR_TIMEOUT(&outentry), 0);
if (!inode) {
@ -692,13 +698,15 @@ static int fuse_create_open(struct inode *dir, struct dentry *entry,
d_instantiate(entry, inode);
fuse_change_entry_timeout(entry, &outentry);
fuse_dir_changed(dir);
err = finish_open(file, entry, generic_file_open);
err = generic_file_open(inode, file);
if (!err) {
file->private_data = ff;
err = finish_open(file, entry, fuse_finish_open);
}
if (err) {
fi = get_fuse_inode(inode);
fuse_sync_release(fi, ff, flags);
} else {
file->private_data = ff;
fuse_finish_open(inode, file);
if (fm->fc->atomic_o_trunc && trunc)
truncate_pagecache(inode, 0);
else if (!(ff->open_flags & FOPEN_KEEP_CACHE))
@ -1210,7 +1218,7 @@ static int fuse_do_statx(struct inode *inode, struct file *file,
if (((sx->mask & STATX_SIZE) && !fuse_valid_size(sx->size)) ||
((sx->mask & STATX_TYPE) && (!fuse_valid_type(sx->mode) ||
inode_wrong_type(inode, sx->mode)))) {
make_bad_inode(inode);
fuse_make_bad(inode);
return -EIO;
}
@ -1485,7 +1493,7 @@ static int fuse_perm_getattr(struct inode *inode, int mask)
*
* 1) Local access checking ('default_permissions' mount option) based
* on file mode. This is the plain old disk filesystem permission
* modell.
* model.
*
* 2) "Remote" access checking, where server is responsible for
* checking permission in each inode operation. An exception to this
@ -1630,7 +1638,30 @@ out_err:
static int fuse_dir_open(struct inode *inode, struct file *file)
{
return fuse_open_common(inode, file, true);
struct fuse_mount *fm = get_fuse_mount(inode);
int err;
if (fuse_is_bad(inode))
return -EIO;
err = generic_file_open(inode, file);
if (err)
return err;
err = fuse_do_open(fm, get_node_id(inode), file, true);
if (!err) {
struct fuse_file *ff = file->private_data;
/*
* Keep handling FOPEN_STREAM and FOPEN_NONSEEKABLE for
* directories for backward compatibility, though it's unlikely
* to be useful.
*/
if (ff->open_flags & (FOPEN_STREAM | FOPEN_NONSEEKABLE))
nonseekable_open(inode, file);
}
return err;
}
static int fuse_dir_release(struct inode *inode, struct file *file)

459
fs/fuse/file.c
View File

@ -20,6 +20,7 @@
#include <linux/fs.h>
#include <linux/filelock.h>
#include <linux/splice.h>
#include <linux/task_io_accounting_ops.h>
static int fuse_send_open(struct fuse_mount *fm, u64 nodeid,
unsigned int open_flags, int opcode,
@ -50,13 +51,7 @@ static int fuse_send_open(struct fuse_mount *fm, u64 nodeid,
return fuse_simple_request(fm, &args);
}
struct fuse_release_args {
struct fuse_args args;
struct fuse_release_in inarg;
struct inode *inode;
};
struct fuse_file *fuse_file_alloc(struct fuse_mount *fm)
struct fuse_file *fuse_file_alloc(struct fuse_mount *fm, bool release)
{
struct fuse_file *ff;
@ -65,15 +60,15 @@ struct fuse_file *fuse_file_alloc(struct fuse_mount *fm)
return NULL;
ff->fm = fm;
ff->release_args = kzalloc(sizeof(*ff->release_args),
GFP_KERNEL_ACCOUNT);
if (!ff->release_args) {
kfree(ff);
return NULL;
if (release) {
ff->args = kzalloc(sizeof(*ff->args), GFP_KERNEL_ACCOUNT);
if (!ff->args) {
kfree(ff);
return NULL;
}
}
INIT_LIST_HEAD(&ff->write_entry);
mutex_init(&ff->readdir.lock);
refcount_set(&ff->count, 1);
RB_CLEAR_NODE(&ff->polled_node);
init_waitqueue_head(&ff->poll_wait);
@ -85,8 +80,7 @@ struct fuse_file *fuse_file_alloc(struct fuse_mount *fm)
void fuse_file_free(struct fuse_file *ff)
{
kfree(ff->release_args);
mutex_destroy(&ff->readdir.lock);
kfree(ff->args);
kfree(ff);
}
@ -105,14 +99,17 @@ static void fuse_release_end(struct fuse_mount *fm, struct fuse_args *args,
kfree(ra);
}
static void fuse_file_put(struct fuse_file *ff, bool sync, bool isdir)
static void fuse_file_put(struct fuse_file *ff, bool sync)
{
if (refcount_dec_and_test(&ff->count)) {
struct fuse_args *args = &ff->release_args->args;
struct fuse_release_args *ra = &ff->args->release_args;
struct fuse_args *args = (ra ? &ra->args : NULL);
if (isdir ? ff->fm->fc->no_opendir : ff->fm->fc->no_open) {
/* Do nothing when client does not implement 'open' */
fuse_release_end(ff->fm, args, 0);
if (ra && ra->inode)
fuse_file_io_release(ff, ra->inode);
if (!args) {
/* Do nothing when server does not implement 'open' */
} else if (sync) {
fuse_simple_request(ff->fm, args);
fuse_release_end(ff->fm, args, 0);
@ -132,27 +129,31 @@ struct fuse_file *fuse_file_open(struct fuse_mount *fm, u64 nodeid,
struct fuse_conn *fc = fm->fc;
struct fuse_file *ff;
int opcode = isdir ? FUSE_OPENDIR : FUSE_OPEN;
bool open = isdir ? !fc->no_opendir : !fc->no_open;
ff = fuse_file_alloc(fm);
ff = fuse_file_alloc(fm, open);
if (!ff)
return ERR_PTR(-ENOMEM);
ff->fh = 0;
/* Default for no-open */
ff->open_flags = FOPEN_KEEP_CACHE | (isdir ? FOPEN_CACHE_DIR : 0);
if (isdir ? !fc->no_opendir : !fc->no_open) {
struct fuse_open_out outarg;
if (open) {
/* Store outarg for fuse_finish_open() */
struct fuse_open_out *outargp = &ff->args->open_outarg;
int err;
err = fuse_send_open(fm, nodeid, open_flags, opcode, &outarg);
err = fuse_send_open(fm, nodeid, open_flags, opcode, outargp);
if (!err) {
ff->fh = outarg.fh;
ff->open_flags = outarg.open_flags;
ff->fh = outargp->fh;
ff->open_flags = outargp->open_flags;
} else if (err != -ENOSYS) {
fuse_file_free(ff);
return ERR_PTR(err);
} else {
/* No release needed */
kfree(ff->args);
ff->args = NULL;
if (isdir)
fc->no_opendir = 1;
else
@ -195,40 +196,50 @@ static void fuse_link_write_file(struct file *file)
spin_unlock(&fi->lock);
}
void fuse_finish_open(struct inode *inode, struct file *file)
int fuse_finish_open(struct inode *inode, struct file *file)
{
struct fuse_file *ff = file->private_data;
struct fuse_conn *fc = get_fuse_conn(inode);
int err;
err = fuse_file_io_open(file, inode);
if (err)
return err;
if (ff->open_flags & FOPEN_STREAM)
stream_open(inode, file);
else if (ff->open_flags & FOPEN_NONSEEKABLE)
nonseekable_open(inode, file);
if (fc->atomic_o_trunc && (file->f_flags & O_TRUNC)) {
struct fuse_inode *fi = get_fuse_inode(inode);
spin_lock(&fi->lock);
fi->attr_version = atomic64_inc_return(&fc->attr_version);
i_size_write(inode, 0);
spin_unlock(&fi->lock);
file_update_time(file);
fuse_invalidate_attr_mask(inode, FUSE_STATX_MODSIZE);
}
if ((file->f_mode & FMODE_WRITE) && fc->writeback_cache)
fuse_link_write_file(file);
return 0;
}
int fuse_open_common(struct inode *inode, struct file *file, bool isdir)
static void fuse_truncate_update_attr(struct inode *inode, struct file *file)
{
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_inode *fi = get_fuse_inode(inode);
spin_lock(&fi->lock);
fi->attr_version = atomic64_inc_return(&fc->attr_version);
i_size_write(inode, 0);
spin_unlock(&fi->lock);
file_update_time(file);
fuse_invalidate_attr_mask(inode, FUSE_STATX_MODSIZE);
}
static int fuse_open(struct inode *inode, struct file *file)
{
struct fuse_mount *fm = get_fuse_mount(inode);
struct fuse_inode *fi = get_fuse_inode(inode);
struct fuse_conn *fc = fm->fc;
struct fuse_file *ff;
int err;
bool is_wb_truncate = (file->f_flags & O_TRUNC) &&
fc->atomic_o_trunc &&
fc->writeback_cache;
bool dax_truncate = (file->f_flags & O_TRUNC) &&
fc->atomic_o_trunc && FUSE_IS_DAX(inode);
bool is_truncate = (file->f_flags & O_TRUNC) && fc->atomic_o_trunc;
bool is_wb_truncate = is_truncate && fc->writeback_cache;
bool dax_truncate = is_truncate && FUSE_IS_DAX(inode);
if (fuse_is_bad(inode))
return -EIO;
@ -250,16 +261,20 @@ int fuse_open_common(struct inode *inode, struct file *file, bool isdir)
if (is_wb_truncate || dax_truncate)
fuse_set_nowrite(inode);
err = fuse_do_open(fm, get_node_id(inode), file, isdir);
if (!err)
fuse_finish_open(inode, file);
err = fuse_do_open(fm, get_node_id(inode), file, false);
if (!err) {
ff = file->private_data;
err = fuse_finish_open(inode, file);
if (err)
fuse_sync_release(fi, ff, file->f_flags);
else if (is_truncate)
fuse_truncate_update_attr(inode, file);
}
if (is_wb_truncate || dax_truncate)
fuse_release_nowrite(inode);
if (!err) {
struct fuse_file *ff = file->private_data;
if (fc->atomic_o_trunc && (file->f_flags & O_TRUNC))
if (is_truncate)
truncate_pagecache(inode, 0);
else if (!(ff->open_flags & FOPEN_KEEP_CACHE))
invalidate_inode_pages2(inode->i_mapping);
@ -274,10 +289,13 @@ out_inode_unlock:
}
static void fuse_prepare_release(struct fuse_inode *fi, struct fuse_file *ff,
unsigned int flags, int opcode)
unsigned int flags, int opcode, bool sync)
{
struct fuse_conn *fc = ff->fm->fc;
struct fuse_release_args *ra = ff->release_args;
struct fuse_release_args *ra = &ff->args->release_args;
if (fuse_file_passthrough(ff))
fuse_passthrough_release(ff, fuse_inode_backing(fi));
/* Inode is NULL on error path of fuse_create_open() */
if (likely(fi)) {
@ -292,6 +310,11 @@ static void fuse_prepare_release(struct fuse_inode *fi, struct fuse_file *ff,
wake_up_interruptible_all(&ff->poll_wait);
if (!ra)
return;
/* ff->args was used for open outarg */
memset(ff->args, 0, sizeof(*ff->args));
ra->inarg.fh = ff->fh;
ra->inarg.flags = flags;
ra->args.in_numargs = 1;
@ -301,23 +324,28 @@ static void fuse_prepare_release(struct fuse_inode *fi, struct fuse_file *ff,
ra->args.nodeid = ff->nodeid;
ra->args.force = true;
ra->args.nocreds = true;
/*
* Hold inode until release is finished.
* From fuse_sync_release() the refcount is 1 and everything's
* synchronous, so we are fine with not doing igrab() here.
*/
ra->inode = sync ? NULL : igrab(&fi->inode);
}
void fuse_file_release(struct inode *inode, struct fuse_file *ff,
unsigned int open_flags, fl_owner_t id, bool isdir)
{
struct fuse_inode *fi = get_fuse_inode(inode);
struct fuse_release_args *ra = ff->release_args;
struct fuse_release_args *ra = &ff->args->release_args;
int opcode = isdir ? FUSE_RELEASEDIR : FUSE_RELEASE;
fuse_prepare_release(fi, ff, open_flags, opcode);
fuse_prepare_release(fi, ff, open_flags, opcode, false);
if (ff->flock) {
if (ra && ff->flock) {
ra->inarg.release_flags |= FUSE_RELEASE_FLOCK_UNLOCK;
ra->inarg.lock_owner = fuse_lock_owner_id(ff->fm->fc, id);
}
/* Hold inode until release is finished */
ra->inode = igrab(inode);
/*
* Normally this will send the RELEASE request, however if
@ -328,7 +356,7 @@ void fuse_file_release(struct inode *inode, struct fuse_file *ff,
* synchronous RELEASE is allowed (and desirable) in this case
* because the server can be trusted not to screw up.
*/
fuse_file_put(ff, ff->fm->fc->destroy, isdir);
fuse_file_put(ff, ff->fm->fc->destroy);
}
void fuse_release_common(struct file *file, bool isdir)
@ -337,11 +365,6 @@ void fuse_release_common(struct file *file, bool isdir)
(fl_owner_t) file, isdir);
}
static int fuse_open(struct inode *inode, struct file *file)
{
return fuse_open_common(inode, file, false);
}
static int fuse_release(struct inode *inode, struct file *file)
{
struct fuse_conn *fc = get_fuse_conn(inode);
@ -363,12 +386,8 @@ void fuse_sync_release(struct fuse_inode *fi, struct fuse_file *ff,
unsigned int flags)
{
WARN_ON(refcount_read(&ff->count) > 1);
fuse_prepare_release(fi, ff, flags, FUSE_RELEASE);
/*
* iput(NULL) is a no-op and since the refcount is 1 and everything's
* synchronous, we are fine with not doing igrab() here"
*/
fuse_file_put(ff, true, false);
fuse_prepare_release(fi, ff, flags, FUSE_RELEASE, true);
fuse_file_put(ff, true);
}
EXPORT_SYMBOL_GPL(fuse_sync_release);
@ -634,7 +653,8 @@ static void fuse_release_user_pages(struct fuse_args_pages *ap,
for (i = 0; i < ap->num_pages; i++) {
if (should_dirty)
set_page_dirty_lock(ap->pages[i]);
put_page(ap->pages[i]);
if (ap->args.is_pinned)
unpin_user_page(ap->pages[i]);
}
}
@ -925,7 +945,7 @@ static void fuse_readpages_end(struct fuse_mount *fm, struct fuse_args *args,
put_page(page);
}
if (ia->ff)
fuse_file_put(ia->ff, false, false);
fuse_file_put(ia->ff, false);
fuse_io_free(ia);
}
@ -1299,13 +1319,93 @@ static ssize_t fuse_perform_write(struct kiocb *iocb, struct iov_iter *ii)
return res;
}
static bool fuse_io_past_eof(struct kiocb *iocb, struct iov_iter *iter)
{
struct inode *inode = file_inode(iocb->ki_filp);
return iocb->ki_pos + iov_iter_count(iter) > i_size_read(inode);
}
/*
* @return true if an exclusive lock for direct IO writes is needed
*/
static bool fuse_dio_wr_exclusive_lock(struct kiocb *iocb, struct iov_iter *from)
{
struct file *file = iocb->ki_filp;
struct fuse_file *ff = file->private_data;
struct inode *inode = file_inode(iocb->ki_filp);
struct fuse_inode *fi = get_fuse_inode(inode);
/* Server side has to advise that it supports parallel dio writes. */
if (!(ff->open_flags & FOPEN_PARALLEL_DIRECT_WRITES))
return true;
/*
* Append will need to know the eventual EOF - always needs an
* exclusive lock.
*/
if (iocb->ki_flags & IOCB_APPEND)
return true;
/* shared locks are not allowed with parallel page cache IO */
if (test_bit(FUSE_I_CACHE_IO_MODE, &fi->state))
return false;
/* Parallel dio beyond EOF is not supported, at least for now. */
if (fuse_io_past_eof(iocb, from))
return true;
return false;
}
static void fuse_dio_lock(struct kiocb *iocb, struct iov_iter *from,
bool *exclusive)
{
struct inode *inode = file_inode(iocb->ki_filp);
struct fuse_file *ff = iocb->ki_filp->private_data;
*exclusive = fuse_dio_wr_exclusive_lock(iocb, from);
if (*exclusive) {
inode_lock(inode);
} else {
inode_lock_shared(inode);
/*
* New parallal dio allowed only if inode is not in caching
* mode and denies new opens in caching mode. This check
* should be performed only after taking shared inode lock.
* Previous past eof check was without inode lock and might
* have raced, so check it again.
*/
if (fuse_io_past_eof(iocb, from) ||
fuse_file_uncached_io_start(inode, ff, NULL) != 0) {
inode_unlock_shared(inode);
inode_lock(inode);
*exclusive = true;
}
}
}
static void fuse_dio_unlock(struct kiocb *iocb, bool exclusive)
{
struct inode *inode = file_inode(iocb->ki_filp);
struct fuse_file *ff = iocb->ki_filp->private_data;
if (exclusive) {
inode_unlock(inode);
} else {
/* Allow opens in caching mode after last parallel dio end */
fuse_file_uncached_io_end(inode, ff);
inode_unlock_shared(inode);
}
}
static ssize_t fuse_cache_write_iter(struct kiocb *iocb, struct iov_iter *from)
{
struct file *file = iocb->ki_filp;
struct address_space *mapping = file->f_mapping;
ssize_t written = 0;
struct inode *inode = mapping->host;
ssize_t err;
ssize_t err, count;
struct fuse_conn *fc = get_fuse_conn(inode);
if (fc->writeback_cache) {
@ -1327,10 +1427,12 @@ static ssize_t fuse_cache_write_iter(struct kiocb *iocb, struct iov_iter *from)
writethrough:
inode_lock(inode);
err = generic_write_checks(iocb, from);
err = count = generic_write_checks(iocb, from);
if (err <= 0)
goto out;
task_io_account_write(count);
err = file_remove_privs(file);
if (err)
goto out;
@ -1392,10 +1494,13 @@ static int fuse_get_user_pages(struct fuse_args_pages *ap, struct iov_iter *ii,
while (nbytes < *nbytesp && ap->num_pages < max_pages) {
unsigned npages;
size_t start;
ret = iov_iter_get_pages2(ii, &ap->pages[ap->num_pages],
*nbytesp - nbytes,
max_pages - ap->num_pages,
&start);
struct page **pt_pages;
pt_pages = &ap->pages[ap->num_pages];
ret = iov_iter_extract_pages(ii, &pt_pages,
*nbytesp - nbytes,
max_pages - ap->num_pages,
0, &start);
if (ret < 0)
break;
@ -1412,6 +1517,7 @@ static int fuse_get_user_pages(struct fuse_args_pages *ap, struct iov_iter *ii,
(PAGE_SIZE - ret) & (PAGE_SIZE - 1);
}
ap->args.is_pinned = iov_iter_extract_will_pin(ii);
ap->args.user_pages = true;
if (write)
ap->args.in_pages = true;
@ -1558,51 +1664,17 @@ static ssize_t fuse_direct_read_iter(struct kiocb *iocb, struct iov_iter *to)
return res;
}
static bool fuse_direct_write_extending_i_size(struct kiocb *iocb,
struct iov_iter *iter)
{
struct inode *inode = file_inode(iocb->ki_filp);
return iocb->ki_pos + iov_iter_count(iter) > i_size_read(inode);
}
static ssize_t fuse_direct_write_iter(struct kiocb *iocb, struct iov_iter *from)
{
struct inode *inode = file_inode(iocb->ki_filp);
struct file *file = iocb->ki_filp;
struct fuse_file *ff = file->private_data;
struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb);
ssize_t res;
bool exclusive_lock =
!(ff->open_flags & FOPEN_PARALLEL_DIRECT_WRITES) ||
get_fuse_conn(inode)->direct_io_allow_mmap ||
iocb->ki_flags & IOCB_APPEND ||
fuse_direct_write_extending_i_size(iocb, from);
/*
* Take exclusive lock if
* - Parallel direct writes are disabled - a user space decision
* - Parallel direct writes are enabled and i_size is being extended.
* - Shared mmap on direct_io file is supported (FUSE_DIRECT_IO_ALLOW_MMAP).
* This might not be needed at all, but needs further investigation.
*/
if (exclusive_lock)
inode_lock(inode);
else {
inode_lock_shared(inode);
/* A race with truncate might have come up as the decision for
* the lock type was done without holding the lock, check again.
*/
if (fuse_direct_write_extending_i_size(iocb, from)) {
inode_unlock_shared(inode);
inode_lock(inode);
exclusive_lock = true;
}
}
bool exclusive;
fuse_dio_lock(iocb, from, &exclusive);
res = generic_write_checks(iocb, from);
if (res > 0) {
task_io_account_write(res);
if (!is_sync_kiocb(iocb) && iocb->ki_flags & IOCB_DIRECT) {
res = fuse_direct_IO(iocb, from);
} else {
@ -1611,10 +1683,7 @@ static ssize_t fuse_direct_write_iter(struct kiocb *iocb, struct iov_iter *from)
fuse_write_update_attr(inode, iocb->ki_pos, res);
}
}
if (exclusive_lock)
inode_unlock(inode);
else
inode_unlock_shared(inode);
fuse_dio_unlock(iocb, exclusive);
return res;
}
@ -1631,10 +1700,13 @@ static ssize_t fuse_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
if (FUSE_IS_DAX(inode))
return fuse_dax_read_iter(iocb, to);
if (!(ff->open_flags & FOPEN_DIRECT_IO))
return fuse_cache_read_iter(iocb, to);
else
/* FOPEN_DIRECT_IO overrides FOPEN_PASSTHROUGH */
if (ff->open_flags & FOPEN_DIRECT_IO)
return fuse_direct_read_iter(iocb, to);
else if (fuse_file_passthrough(ff))
return fuse_passthrough_read_iter(iocb, to);
else
return fuse_cache_read_iter(iocb, to);
}
static ssize_t fuse_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
@ -1649,10 +1721,38 @@ static ssize_t fuse_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
if (FUSE_IS_DAX(inode))
return fuse_dax_write_iter(iocb, from);
if (!(ff->open_flags & FOPEN_DIRECT_IO))
return fuse_cache_write_iter(iocb, from);
else
/* FOPEN_DIRECT_IO overrides FOPEN_PASSTHROUGH */
if (ff->open_flags & FOPEN_DIRECT_IO)
return fuse_direct_write_iter(iocb, from);
else if (fuse_file_passthrough(ff))
return fuse_passthrough_write_iter(iocb, from);
else
return fuse_cache_write_iter(iocb, from);
}
static ssize_t fuse_splice_read(struct file *in, loff_t *ppos,
struct pipe_inode_info *pipe, size_t len,
unsigned int flags)
{
struct fuse_file *ff = in->private_data;
/* FOPEN_DIRECT_IO overrides FOPEN_PASSTHROUGH */
if (fuse_file_passthrough(ff) && !(ff->open_flags & FOPEN_DIRECT_IO))
return fuse_passthrough_splice_read(in, ppos, pipe, len, flags);
else
return filemap_splice_read(in, ppos, pipe, len, flags);
}
static ssize_t fuse_splice_write(struct pipe_inode_info *pipe, struct file *out,
loff_t *ppos, size_t len, unsigned int flags)
{
struct fuse_file *ff = out->private_data;
/* FOPEN_DIRECT_IO overrides FOPEN_PASSTHROUGH */
if (fuse_file_passthrough(ff) && !(ff->open_flags & FOPEN_DIRECT_IO))
return fuse_passthrough_splice_write(pipe, out, ppos, len, flags);
else
return iter_file_splice_write(pipe, out, ppos, len, flags);
}
static void fuse_writepage_free(struct fuse_writepage_args *wpa)
@ -1667,7 +1767,7 @@ static void fuse_writepage_free(struct fuse_writepage_args *wpa)
__free_page(ap->pages[i]);
if (wpa->ia.ff)
fuse_file_put(wpa->ia.ff, false, false);
fuse_file_put(wpa->ia.ff, false);
kfree(ap->pages);
kfree(wpa);
@ -1909,7 +2009,7 @@ int fuse_write_inode(struct inode *inode, struct writeback_control *wbc)
ff = __fuse_write_file_get(fi);
err = fuse_flush_times(inode, ff);
if (ff)
fuse_file_put(ff, false, false);
fuse_file_put(ff, false);
return err;
}
@ -1947,26 +2047,26 @@ static void fuse_writepage_add_to_bucket(struct fuse_conn *fc,
rcu_read_unlock();
}
static int fuse_writepage_locked(struct page *page)
static int fuse_writepage_locked(struct folio *folio)
{
struct address_space *mapping = page->mapping;
struct address_space *mapping = folio->mapping;
struct inode *inode = mapping->host;
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_inode *fi = get_fuse_inode(inode);
struct fuse_writepage_args *wpa;
struct fuse_args_pages *ap;
struct page *tmp_page;
struct folio *tmp_folio;
int error = -ENOMEM;
set_page_writeback(page);
folio_start_writeback(folio);
wpa = fuse_writepage_args_alloc();
if (!wpa)
goto err;
ap = &wpa->ia.ap;
tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
if (!tmp_page)
tmp_folio = folio_alloc(GFP_NOFS | __GFP_HIGHMEM, 0);
if (!tmp_folio)
goto err_free;
error = -EIO;
@ -1975,21 +2075,21 @@ static int fuse_writepage_locked(struct page *page)
goto err_nofile;
fuse_writepage_add_to_bucket(fc, wpa);
fuse_write_args_fill(&wpa->ia, wpa->ia.ff, page_offset(page), 0);
fuse_write_args_fill(&wpa->ia, wpa->ia.ff, folio_pos(folio), 0);
copy_highpage(tmp_page, page);
folio_copy(tmp_folio, folio);
wpa->ia.write.in.write_flags |= FUSE_WRITE_CACHE;
wpa->next = NULL;
ap->args.in_pages = true;
ap->num_pages = 1;
ap->pages[0] = tmp_page;
ap->pages[0] = &tmp_folio->page;
ap->descs[0].offset = 0;
ap->descs[0].length = PAGE_SIZE;
ap->args.end = fuse_writepage_end;
wpa->inode = inode;
inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK);
inc_node_page_state(tmp_page, NR_WRITEBACK_TEMP);
node_stat_add_folio(tmp_folio, NR_WRITEBACK_TEMP);
spin_lock(&fi->lock);
tree_insert(&fi->writepages, wpa);
@ -1997,48 +2097,20 @@ static int fuse_writepage_locked(struct page *page)
fuse_flush_writepages(inode);
spin_unlock(&fi->lock);
end_page_writeback(page);
folio_end_writeback(folio);
return 0;
err_nofile:
__free_page(tmp_page);
folio_put(tmp_folio);
err_free:
kfree(wpa);
err:
mapping_set_error(page->mapping, error);
end_page_writeback(page);
mapping_set_error(folio->mapping, error);
folio_end_writeback(folio);
return error;
}
static int fuse_writepage(struct page *page, struct writeback_control *wbc)
{
struct fuse_conn *fc = get_fuse_conn(page->mapping->host);
int err;
if (fuse_page_is_writeback(page->mapping->host, page->index)) {
/*
* ->writepages() should be called for sync() and friends. We
* should only get here on direct reclaim and then we are
* allowed to skip a page which is already in flight
*/
WARN_ON(wbc->sync_mode == WB_SYNC_ALL);
redirty_page_for_writepage(wbc, page);
unlock_page(page);
return 0;
}
if (wbc->sync_mode == WB_SYNC_NONE &&
fc->num_background >= fc->congestion_threshold)
return AOP_WRITEPAGE_ACTIVATE;
err = fuse_writepage_locked(page);
unlock_page(page);
return err;
}
struct fuse_fill_wb_data {
struct fuse_writepage_args *wpa;
struct fuse_file *ff;
@ -2307,7 +2379,7 @@ static int fuse_writepages(struct address_space *mapping,
fuse_writepages_send(&data);
}
if (data.ff)
fuse_file_put(data.ff, false, false);
fuse_file_put(data.ff, false);
kfree(data.orig_pages);
out:
@ -2401,7 +2473,7 @@ static int fuse_launder_folio(struct folio *folio)
/* Serialize with pending writeback for the same page */
fuse_wait_on_page_writeback(inode, folio->index);
err = fuse_writepage_locked(&folio->page);
err = fuse_writepage_locked(folio);
if (!err)
fuse_wait_on_page_writeback(inode, folio->index);
}
@ -2462,13 +2534,30 @@ static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
{
struct fuse_file *ff = file->private_data;
struct fuse_conn *fc = ff->fm->fc;
struct inode *inode = file_inode(file);
int rc;
/* DAX mmap is superior to direct_io mmap */
if (FUSE_IS_DAX(file_inode(file)))
if (FUSE_IS_DAX(inode))
return fuse_dax_mmap(file, vma);
/*
* If inode is in passthrough io mode, because it has some file open
* in passthrough mode, either mmap to backing file or fail mmap,
* because mixing cached mmap and passthrough io mode is not allowed.
*/
if (fuse_file_passthrough(ff))
return fuse_passthrough_mmap(file, vma);
else if (fuse_inode_backing(get_fuse_inode(inode)))
return -ENODEV;
/*
* FOPEN_DIRECT_IO handling is special compared to O_DIRECT,
* as does not allow MAP_SHARED mmap without FUSE_DIRECT_IO_ALLOW_MMAP.
*/
if (ff->open_flags & FOPEN_DIRECT_IO) {
/* Can't provide the coherency needed for MAP_SHARED
/*
* Can't provide the coherency needed for MAP_SHARED
* if FUSE_DIRECT_IO_ALLOW_MMAP isn't set.
*/
if ((vma->vm_flags & VM_MAYSHARE) && !fc->direct_io_allow_mmap)
@ -2476,7 +2565,19 @@ static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
invalidate_inode_pages2(file->f_mapping);
return generic_file_mmap(file, vma);
if (!(vma->vm_flags & VM_MAYSHARE)) {
/* MAP_PRIVATE */
return generic_file_mmap(file, vma);
}
/*
* First mmap of direct_io file enters caching inode io mode.
* Also waits for parallel dio writers to go into serial mode
* (exclusive instead of shared lock).
*/
rc = fuse_file_cached_io_start(inode, ff);
if (rc)
return rc;
}
if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE))
@ -2580,10 +2681,6 @@ static int fuse_setlk(struct file *file, struct file_lock *fl, int flock)
return -ENOLCK;
}
/* Unlock on close is handled by the flush method */
if ((fl->c.flc_flags & FL_CLOSE_POSIX) == FL_CLOSE_POSIX)
return 0;
fuse_lk_fill(&args, file, fl, opcode, pid_nr, flock, &inarg);
err = fuse_simple_request(fm, &args);
@ -3213,8 +3310,8 @@ static const struct file_operations fuse_file_operations = {
.lock = fuse_file_lock,
.get_unmapped_area = thp_get_unmapped_area,
.flock = fuse_file_flock,
.splice_read = filemap_splice_read,
.splice_write = iter_file_splice_write,
.splice_read = fuse_splice_read,
.splice_write = fuse_splice_write,
.unlocked_ioctl = fuse_file_ioctl,
.compat_ioctl = fuse_file_compat_ioctl,
.poll = fuse_file_poll,
@ -3225,10 +3322,10 @@ static const struct file_operations fuse_file_operations = {
static const struct address_space_operations fuse_file_aops = {
.read_folio = fuse_read_folio,
.readahead = fuse_readahead,
.writepage = fuse_writepage,
.writepages = fuse_writepages,
.launder_folio = fuse_launder_folio,
.dirty_folio = filemap_dirty_folio,
.migrate_folio = filemap_migrate_folio,
.bmap = fuse_bmap,
.direct_IO = fuse_direct_IO,
.write_begin = fuse_write_begin,
@ -3245,7 +3342,9 @@ void fuse_init_file_inode(struct inode *inode, unsigned int flags)
INIT_LIST_HEAD(&fi->write_files);
INIT_LIST_HEAD(&fi->queued_writes);
fi->writectr = 0;
fi->iocachectr = 0;
init_waitqueue_head(&fi->page_waitq);
init_waitqueue_head(&fi->direct_io_waitq);
fi->writepages = RB_ROOT;
if (IS_ENABLED(CONFIG_FUSE_DAX))

153
fs/fuse/fuse_i.h
View File

@ -76,6 +76,16 @@ struct fuse_submount_lookup {
struct fuse_forget_link *forget;
};
/** Container for data related to mapping to backing file */
struct fuse_backing {
struct file *file;
struct cred *cred;
/** refcount */
refcount_t count;
struct rcu_head rcu;
};
/** FUSE inode */
struct fuse_inode {
/** Inode data */
@ -111,7 +121,7 @@ struct fuse_inode {
u64 attr_version;
union {
/* Write related fields (regular file only) */
/* read/write io cache (regular file only) */
struct {
/* Files usable in writepage. Protected by fi->lock */
struct list_head write_files;
@ -123,9 +133,15 @@ struct fuse_inode {
* (FUSE_NOWRITE) means more writes are blocked */
int writectr;
/** Number of files/maps using page cache */
int iocachectr;
/* Waitq for writepage completion */
wait_queue_head_t page_waitq;
/* waitq for direct-io completion */
wait_queue_head_t direct_io_waitq;
/* List of writepage requestst (pending or sent) */
struct rb_root writepages;
};
@ -173,6 +189,10 @@ struct fuse_inode {
#endif
/** Submount specific lookup tracking */
struct fuse_submount_lookup *submount_lookup;
#ifdef CONFIG_FUSE_PASSTHROUGH
/** Reference to backing file in passthrough mode */
struct fuse_backing *fb;
#endif
};
/** FUSE inode state bits */
@ -187,19 +207,21 @@ enum {
FUSE_I_BAD,
/* Has btime */
FUSE_I_BTIME,
/* Wants or already has page cache IO */
FUSE_I_CACHE_IO_MODE,
};
struct fuse_conn;
struct fuse_mount;
struct fuse_release_args;
union fuse_file_args;
/** FUSE specific file data */
struct fuse_file {
/** Fuse connection for this file */
struct fuse_mount *fm;
/* Argument space reserved for release */
struct fuse_release_args *release_args;
/* Argument space reserved for open/release */
union fuse_file_args *args;
/** Kernel file handle guaranteed to be unique */
u64 kh;
@ -221,12 +243,6 @@ struct fuse_file {
/* Readdir related */
struct {
/*
* Protects below fields against (crazy) parallel readdir on
* same open file. Uncontended in the normal case.
*/
struct mutex lock;
/* Dir stream position */
loff_t pos;
@ -244,6 +260,15 @@ struct fuse_file {
/** Wait queue head for poll */
wait_queue_head_t poll_wait;
/** Does file hold a fi->iocachectr refcount? */
enum { IOM_NONE, IOM_CACHED, IOM_UNCACHED } iomode;
#ifdef CONFIG_FUSE_PASSTHROUGH
/** Reference to backing file in passthrough mode */
struct file *passthrough;
const struct cred *cred;
#endif
/** Has flock been performed on this file? */
bool flock:1;
};
@ -283,6 +308,7 @@ struct fuse_args {
bool page_replace:1;
bool may_block:1;
bool is_ext:1;
bool is_pinned:1;
struct fuse_in_arg in_args[3];
struct fuse_arg out_args[2];
void (*end)(struct fuse_mount *fm, struct fuse_args *args, int error);
@ -295,6 +321,19 @@ struct fuse_args_pages {
unsigned int num_pages;
};
struct fuse_release_args {
struct fuse_args args;
struct fuse_release_in inarg;
struct inode *inode;
};
union fuse_file_args {
/* Used during open() */
struct fuse_open_out open_outarg;
/* Used during release() */
struct fuse_release_args release_args;
};
#define FUSE_ARGS(args) struct fuse_args args = {}
/** The request IO state (for asynchronous processing) */
@ -818,6 +857,12 @@ struct fuse_conn {
/* Is statx not implemented by fs? */
unsigned int no_statx:1;
/** Passthrough support for read/write IO */
unsigned int passthrough:1;
/** Maximum stack depth for passthrough backing files */
int max_stack_depth;
/** The number of requests waiting for completion */
atomic_t num_waiting;
@ -867,6 +912,11 @@ struct fuse_conn {
/* New writepages go into this bucket */
struct fuse_sync_bucket __rcu *curr_bucket;
#ifdef CONFIG_FUSE_PASSTHROUGH
/** IDR for backing files ids */
struct idr backing_files_map;
#endif
};
/*
@ -940,7 +990,6 @@ static inline bool fuse_stale_inode(const struct inode *inode, int generation,
static inline void fuse_make_bad(struct inode *inode)
{
remove_inode_hash(inode);
set_bit(FUSE_I_BAD, &get_fuse_inode(inode)->state);
}
@ -1032,14 +1081,9 @@ void fuse_read_args_fill(struct fuse_io_args *ia, struct file *file, loff_t pos,
size_t count, int opcode);
/**
* Send OPEN or OPENDIR request
*/
int fuse_open_common(struct inode *inode, struct file *file, bool isdir);
struct fuse_file *fuse_file_alloc(struct fuse_mount *fm);
struct fuse_file *fuse_file_alloc(struct fuse_mount *fm, bool release);
void fuse_file_free(struct fuse_file *ff);
void fuse_finish_open(struct inode *inode, struct file *file);
int fuse_finish_open(struct inode *inode, struct file *file);
void fuse_sync_release(struct fuse_inode *fi, struct fuse_file *ff,
unsigned int flags);
@ -1349,11 +1393,82 @@ int fuse_fileattr_get(struct dentry *dentry, struct fileattr *fa);
int fuse_fileattr_set(struct mnt_idmap *idmap,
struct dentry *dentry, struct fileattr *fa);
/* file.c */
/* iomode.c */
int fuse_file_cached_io_start(struct inode *inode, struct fuse_file *ff);
int fuse_file_uncached_io_start(struct inode *inode, struct fuse_file *ff, struct fuse_backing *fb);
void fuse_file_uncached_io_end(struct inode *inode, struct fuse_file *ff);
int fuse_file_io_open(struct file *file, struct inode *inode);
void fuse_file_io_release(struct fuse_file *ff, struct inode *inode);
/* file.c */
struct fuse_file *fuse_file_open(struct fuse_mount *fm, u64 nodeid,
unsigned int open_flags, bool isdir);
void fuse_file_release(struct inode *inode, struct fuse_file *ff,
unsigned int open_flags, fl_owner_t id, bool isdir);
/* passthrough.c */
static inline struct fuse_backing *fuse_inode_backing(struct fuse_inode *fi)
{
#ifdef CONFIG_FUSE_PASSTHROUGH
return READ_ONCE(fi->fb);
#else
return NULL;
#endif
}
static inline struct fuse_backing *fuse_inode_backing_set(struct fuse_inode *fi,
struct fuse_backing *fb)
{
#ifdef CONFIG_FUSE_PASSTHROUGH
return xchg(&fi->fb, fb);
#else
return NULL;
#endif
}
#ifdef CONFIG_FUSE_PASSTHROUGH
struct fuse_backing *fuse_backing_get(struct fuse_backing *fb);
void fuse_backing_put(struct fuse_backing *fb);
#else
static inline struct fuse_backing *fuse_backing_get(struct fuse_backing *fb)
{
return NULL;
}
static inline void fuse_backing_put(struct fuse_backing *fb)
{
}
#endif
void fuse_backing_files_init(struct fuse_conn *fc);
void fuse_backing_files_free(struct fuse_conn *fc);
int fuse_backing_open(struct fuse_conn *fc, struct fuse_backing_map *map);
int fuse_backing_close(struct fuse_conn *fc, int backing_id);
struct fuse_backing *fuse_passthrough_open(struct file *file,
struct inode *inode,
int backing_id);
void fuse_passthrough_release(struct fuse_file *ff, struct fuse_backing *fb);
static inline struct file *fuse_file_passthrough(struct fuse_file *ff)
{
#ifdef CONFIG_FUSE_PASSTHROUGH
return ff->passthrough;
#else
return NULL;
#endif
}
ssize_t fuse_passthrough_read_iter(struct kiocb *iocb, struct iov_iter *iter);
ssize_t fuse_passthrough_write_iter(struct kiocb *iocb, struct iov_iter *iter);
ssize_t fuse_passthrough_splice_read(struct file *in, loff_t *ppos,
struct pipe_inode_info *pipe,
size_t len, unsigned int flags);
ssize_t fuse_passthrough_splice_write(struct pipe_inode_info *pipe,
struct file *out, loff_t *ppos,
size_t len, unsigned int flags);
ssize_t fuse_passthrough_mmap(struct file *file, struct vm_area_struct *vma);
#endif /* _FS_FUSE_I_H */

55
fs/fuse/inode.c
View File

@ -111,6 +111,9 @@ static struct inode *fuse_alloc_inode(struct super_block *sb)
if (IS_ENABLED(CONFIG_FUSE_DAX) && !fuse_dax_inode_alloc(sb, fi))
goto out_free_forget;
if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH))
fuse_inode_backing_set(fi, NULL);
return &fi->inode;
out_free_forget:
@ -129,6 +132,9 @@ static void fuse_free_inode(struct inode *inode)
#ifdef CONFIG_FUSE_DAX
kfree(fi->dax);
#endif
if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH))
fuse_backing_put(fuse_inode_backing(fi));
kmem_cache_free(fuse_inode_cachep, fi);
}
@ -469,8 +475,11 @@ retry:
} else if (fuse_stale_inode(inode, generation, attr)) {
/* nodeid was reused, any I/O on the old inode should fail */
fuse_make_bad(inode);
iput(inode);
goto retry;
if (inode != d_inode(sb->s_root)) {
remove_inode_hash(inode);
iput(inode);
goto retry;
}
}
fi = get_fuse_inode(inode);
spin_lock(&fi->lock);
@ -924,6 +933,9 @@ void fuse_conn_init(struct fuse_conn *fc, struct fuse_mount *fm,
fc->max_pages = FUSE_DEFAULT_MAX_PAGES_PER_REQ;
fc->max_pages_limit = FUSE_MAX_MAX_PAGES;
if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH))
fuse_backing_files_init(fc);
INIT_LIST_HEAD(&fc->mounts);
list_add(&fm->fc_entry, &fc->mounts);
fm->fc = fc;
@ -954,6 +966,8 @@ void fuse_conn_put(struct fuse_conn *fc)
WARN_ON(atomic_read(&bucket->count) != 1);
kfree(bucket);
}
if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH))
fuse_backing_files_free(fc);
call_rcu(&fc->rcu, delayed_release);
}
}
@ -974,7 +988,7 @@ static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode)
attr.mode = mode;
attr.ino = FUSE_ROOT_ID;
attr.nlink = 1;
return fuse_iget(sb, 1, 0, &attr, 0, 0);
return fuse_iget(sb, FUSE_ROOT_ID, 0, &attr, 0, 0);
}
struct fuse_inode_handle {
@ -1117,6 +1131,11 @@ static struct dentry *fuse_get_parent(struct dentry *child)
return parent;
}
/* only for fid encoding; no support for file handle */
static const struct export_operations fuse_export_fid_operations = {
.encode_fh = fuse_encode_fh,
};
static const struct export_operations fuse_export_operations = {
.fh_to_dentry = fuse_fh_to_dentry,
.fh_to_parent = fuse_fh_to_parent,
@ -1291,6 +1310,26 @@ static void process_init_reply(struct fuse_mount *fm, struct fuse_args *args,
fc->create_supp_group = 1;
if (flags & FUSE_DIRECT_IO_ALLOW_MMAP)
fc->direct_io_allow_mmap = 1;
/*
* max_stack_depth is the max stack depth of FUSE fs,
* so it has to be at least 1 to support passthrough
* to backing files.
*
* with max_stack_depth > 1, the backing files can be
* on a stacked fs (e.g. overlayfs) themselves and with
* max_stack_depth == 1, FUSE fs can be stacked as the
* underlying fs of a stacked fs (e.g. overlayfs).
*/
if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH) &&
(flags & FUSE_PASSTHROUGH) &&
arg->max_stack_depth > 0 &&
arg->max_stack_depth <= FILESYSTEM_MAX_STACK_DEPTH) {
fc->passthrough = 1;
fc->max_stack_depth = arg->max_stack_depth;
fm->sb->s_stack_depth = arg->max_stack_depth;
}
if (flags & FUSE_NO_EXPORT_SUPPORT)
fm->sb->s_export_op = &fuse_export_fid_operations;
} else {
ra_pages = fc->max_read / PAGE_SIZE;
fc->no_lock = 1;
@ -1337,7 +1376,8 @@ void fuse_send_init(struct fuse_mount *fm)
FUSE_NO_OPENDIR_SUPPORT | FUSE_EXPLICIT_INVAL_DATA |
FUSE_HANDLE_KILLPRIV_V2 | FUSE_SETXATTR_EXT | FUSE_INIT_EXT |
FUSE_SECURITY_CTX | FUSE_CREATE_SUPP_GROUP |
FUSE_HAS_EXPIRE_ONLY | FUSE_DIRECT_IO_ALLOW_MMAP;
FUSE_HAS_EXPIRE_ONLY | FUSE_DIRECT_IO_ALLOW_MMAP |
FUSE_NO_EXPORT_SUPPORT | FUSE_HAS_RESEND;
#ifdef CONFIG_FUSE_DAX
if (fm->fc->dax)
flags |= FUSE_MAP_ALIGNMENT;
@ -1346,6 +1386,8 @@ void fuse_send_init(struct fuse_mount *fm)
#endif
if (fm->fc->auto_submounts)
flags |= FUSE_SUBMOUNTS;
if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH))
flags |= FUSE_PASSTHROUGH;
ia->in.flags = flags;
ia->in.flags2 = flags >> 32;
@ -1496,8 +1538,8 @@ static void fuse_fill_attr_from_inode(struct fuse_attr *attr,
.ctimensec = ctime.tv_nsec,
.mode = fi->inode.i_mode,
.nlink = fi->inode.i_nlink,
.uid = fi->inode.i_uid.val,
.gid = fi->inode.i_gid.val,
.uid = __kuid_val(fi->inode.i_uid),
.gid = __kgid_val(fi->inode.i_gid),
.rdev = fi->inode.i_rdev,
.blksize = 1u << fi->inode.i_blkbits,
};
@ -1534,6 +1576,7 @@ static int fuse_fill_super_submount(struct super_block *sb,
sb->s_bdi = bdi_get(parent_sb->s_bdi);
sb->s_xattr = parent_sb->s_xattr;
sb->s_export_op = parent_sb->s_export_op;
sb->s_time_gran = parent_sb->s_time_gran;
sb->s_blocksize = parent_sb->s_blocksize;
sb->s_blocksize_bits = parent_sb->s_blocksize_bits;

254
fs/fuse/iomode.c Normal file
View File

@ -0,0 +1,254 @@
// SPDX-License-Identifier: GPL-2.0
/*
* FUSE inode io modes.
*
* Copyright (c) 2024 CTERA Networks.
*/
#include "fuse_i.h"
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/file.h>
#include <linux/fs.h>
/*
* Return true if need to wait for new opens in caching mode.
*/
static inline bool fuse_is_io_cache_wait(struct fuse_inode *fi)
{
return READ_ONCE(fi->iocachectr) < 0 && !fuse_inode_backing(fi);
}
/*
* Start cached io mode.
*
* Blocks new parallel dio writes and waits for the in-progress parallel dio
* writes to complete.
*/
int fuse_file_cached_io_start(struct inode *inode, struct fuse_file *ff)
{
struct fuse_inode *fi = get_fuse_inode(inode);
/* There are no io modes if server does not implement open */
if (!ff->args)
return 0;
spin_lock(&fi->lock);
/*
* Setting the bit advises new direct-io writes to use an exclusive
* lock - without it the wait below might be forever.
*/
while (fuse_is_io_cache_wait(fi)) {
set_bit(FUSE_I_CACHE_IO_MODE, &fi->state);
spin_unlock(&fi->lock);
wait_event(fi->direct_io_waitq, !fuse_is_io_cache_wait(fi));
spin_lock(&fi->lock);
}
/*
* Check if inode entered passthrough io mode while waiting for parallel
* dio write completion.
*/
if (fuse_inode_backing(fi)) {
clear_bit(FUSE_I_CACHE_IO_MODE, &fi->state);
spin_unlock(&fi->lock);
return -ETXTBSY;
}
WARN_ON(ff->iomode == IOM_UNCACHED);
if (ff->iomode == IOM_NONE) {
ff->iomode = IOM_CACHED;
if (fi->iocachectr == 0)
set_bit(FUSE_I_CACHE_IO_MODE, &fi->state);
fi->iocachectr++;
}
spin_unlock(&fi->lock);
return 0;
}
static void fuse_file_cached_io_end(struct inode *inode, struct fuse_file *ff)
{
struct fuse_inode *fi = get_fuse_inode(inode);
spin_lock(&fi->lock);
WARN_ON(fi->iocachectr <= 0);
WARN_ON(ff->iomode != IOM_CACHED);
ff->iomode = IOM_NONE;
fi->iocachectr--;
if (fi->iocachectr == 0)
clear_bit(FUSE_I_CACHE_IO_MODE, &fi->state);
spin_unlock(&fi->lock);
}
/* Start strictly uncached io mode where cache access is not allowed */
int fuse_file_uncached_io_start(struct inode *inode, struct fuse_file *ff, struct fuse_backing *fb)
{
struct fuse_inode *fi = get_fuse_inode(inode);
struct fuse_backing *oldfb;
int err = 0;
spin_lock(&fi->lock);
/* deny conflicting backing files on same fuse inode */
oldfb = fuse_inode_backing(fi);
if (oldfb && oldfb != fb) {
err = -EBUSY;
goto unlock;
}
if (fi->iocachectr > 0) {
err = -ETXTBSY;
goto unlock;
}
WARN_ON(ff->iomode != IOM_NONE);
fi->iocachectr--;
ff->iomode = IOM_UNCACHED;
/* fuse inode holds a single refcount of backing file */
if (!oldfb) {
oldfb = fuse_inode_backing_set(fi, fb);
WARN_ON_ONCE(oldfb != NULL);
} else {
fuse_backing_put(fb);
}
unlock:
spin_unlock(&fi->lock);
return err;
}
void fuse_file_uncached_io_end(struct inode *inode, struct fuse_file *ff)
{
struct fuse_inode *fi = get_fuse_inode(inode);
struct fuse_backing *oldfb = NULL;
spin_lock(&fi->lock);
WARN_ON(fi->iocachectr >= 0);
WARN_ON(ff->iomode != IOM_UNCACHED);
ff->iomode = IOM_NONE;
fi->iocachectr++;
if (!fi->iocachectr) {
wake_up(&fi->direct_io_waitq);
oldfb = fuse_inode_backing_set(fi, NULL);
}
spin_unlock(&fi->lock);
if (oldfb)
fuse_backing_put(oldfb);
}
/*
* Open flags that are allowed in combination with FOPEN_PASSTHROUGH.
* A combination of FOPEN_PASSTHROUGH and FOPEN_DIRECT_IO means that read/write
* operations go directly to the server, but mmap is done on the backing file.
* FOPEN_PASSTHROUGH mode should not co-exist with any users of the fuse inode
* page cache, so FOPEN_KEEP_CACHE is a strange and undesired combination.
*/
#define FOPEN_PASSTHROUGH_MASK \
(FOPEN_PASSTHROUGH | FOPEN_DIRECT_IO | FOPEN_PARALLEL_DIRECT_WRITES | \
FOPEN_NOFLUSH)
static int fuse_file_passthrough_open(struct inode *inode, struct file *file)
{
struct fuse_file *ff = file->private_data;
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_backing *fb;
int err;
/* Check allowed conditions for file open in passthrough mode */
if (!IS_ENABLED(CONFIG_FUSE_PASSTHROUGH) || !fc->passthrough ||
(ff->open_flags & ~FOPEN_PASSTHROUGH_MASK))
return -EINVAL;
fb = fuse_passthrough_open(file, inode,
ff->args->open_outarg.backing_id);
if (IS_ERR(fb))
return PTR_ERR(fb);
/* First passthrough file open denies caching inode io mode */
err = fuse_file_uncached_io_start(inode, ff, fb);
if (!err)
return 0;
fuse_passthrough_release(ff, fb);
fuse_backing_put(fb);
return err;
}
/* Request access to submit new io to inode via open file */
int fuse_file_io_open(struct file *file, struct inode *inode)
{
struct fuse_file *ff = file->private_data;
struct fuse_inode *fi = get_fuse_inode(inode);
int err;
/*
* io modes are not relevant with DAX and with server that does not
* implement open.
*/
if (FUSE_IS_DAX(inode) || !ff->args)
return 0;
/*
* Server is expected to use FOPEN_PASSTHROUGH for all opens of an inode
* which is already open for passthrough.
*/
err = -EINVAL;
if (fuse_inode_backing(fi) && !(ff->open_flags & FOPEN_PASSTHROUGH))
goto fail;
/*
* FOPEN_PARALLEL_DIRECT_WRITES requires FOPEN_DIRECT_IO.
*/
if (!(ff->open_flags & FOPEN_DIRECT_IO))
ff->open_flags &= ~FOPEN_PARALLEL_DIRECT_WRITES;
/*
* First passthrough file open denies caching inode io mode.
* First caching file open enters caching inode io mode.
*
* Note that if user opens a file open with O_DIRECT, but server did
* not specify FOPEN_DIRECT_IO, a later fcntl() could remove O_DIRECT,
* so we put the inode in caching mode to prevent parallel dio.
*/
if ((ff->open_flags & FOPEN_DIRECT_IO) &&
!(ff->open_flags & FOPEN_PASSTHROUGH))
return 0;
if (ff->open_flags & FOPEN_PASSTHROUGH)
err = fuse_file_passthrough_open(inode, file);
else
err = fuse_file_cached_io_start(inode, ff);
if (err)
goto fail;
return 0;
fail:
pr_debug("failed to open file in requested io mode (open_flags=0x%x, err=%i).\n",
ff->open_flags, err);
/*
* The file open mode determines the inode io mode.
* Using incorrect open mode is a server mistake, which results in
* user visible failure of open() with EIO error.
*/
return -EIO;
}
/* No more pending io and no new io possible to inode via open/mmapped file */
void fuse_file_io_release(struct fuse_file *ff, struct inode *inode)
{
/*
* Last parallel dio close allows caching inode io mode.
* Last caching file close exits caching inode io mode.
*/
switch (ff->iomode) {
case IOM_NONE:
/* Nothing to do */
break;
case IOM_UNCACHED:
fuse_file_uncached_io_end(inode, ff);
break;
case IOM_CACHED:
fuse_file_cached_io_end(inode, ff);
break;
}
}

355
fs/fuse/passthrough.c Normal file
View File

@ -0,0 +1,355 @@
// SPDX-License-Identifier: GPL-2.0
/*
* FUSE passthrough to backing file.
*
* Copyright (c) 2023 CTERA Networks.
*/
#include "fuse_i.h"
#include <linux/file.h>
#include <linux/backing-file.h>
#include <linux/splice.h>
static void fuse_file_accessed(struct file *file)
{
struct inode *inode = file_inode(file);
fuse_invalidate_atime(inode);
}
static void fuse_file_modified(struct file *file)
{
struct inode *inode = file_inode(file);
fuse_invalidate_attr_mask(inode, FUSE_STATX_MODSIZE);
}
ssize_t fuse_passthrough_read_iter(struct kiocb *iocb, struct iov_iter *iter)
{
struct file *file = iocb->ki_filp;
struct fuse_file *ff = file->private_data;
struct file *backing_file = fuse_file_passthrough(ff);
size_t count = iov_iter_count(iter);
ssize_t ret;
struct backing_file_ctx ctx = {
.cred = ff->cred,
.user_file = file,
.accessed = fuse_file_accessed,
};
pr_debug("%s: backing_file=0x%p, pos=%lld, len=%zu\n", __func__,
backing_file, iocb->ki_pos, count);
if (!count)
return 0;
ret = backing_file_read_iter(backing_file, iter, iocb, iocb->ki_flags,
&ctx);
return ret;
}
ssize_t fuse_passthrough_write_iter(struct kiocb *iocb,
struct iov_iter *iter)
{
struct file *file = iocb->ki_filp;
struct inode *inode = file_inode(file);
struct fuse_file *ff = file->private_data;
struct file *backing_file = fuse_file_passthrough(ff);
size_t count = iov_iter_count(iter);
ssize_t ret;
struct backing_file_ctx ctx = {
.cred = ff->cred,
.user_file = file,
.end_write = fuse_file_modified,
};
pr_debug("%s: backing_file=0x%p, pos=%lld, len=%zu\n", __func__,
backing_file, iocb->ki_pos, count);
if (!count)
return 0;
inode_lock(inode);
ret = backing_file_write_iter(backing_file, iter, iocb, iocb->ki_flags,
&ctx);
inode_unlock(inode);
return ret;
}
ssize_t fuse_passthrough_splice_read(struct file *in, loff_t *ppos,
struct pipe_inode_info *pipe,
size_t len, unsigned int flags)
{
struct fuse_file *ff = in->private_data;
struct file *backing_file = fuse_file_passthrough(ff);
struct backing_file_ctx ctx = {
.cred = ff->cred,
.user_file = in,
.accessed = fuse_file_accessed,
};
pr_debug("%s: backing_file=0x%p, pos=%lld, len=%zu, flags=0x%x\n", __func__,
backing_file, ppos ? *ppos : 0, len, flags);
return backing_file_splice_read(backing_file, ppos, pipe, len, flags,
&ctx);
}
ssize_t fuse_passthrough_splice_write(struct pipe_inode_info *pipe,
struct file *out, loff_t *ppos,
size_t len, unsigned int flags)
{
struct fuse_file *ff = out->private_data;
struct file *backing_file = fuse_file_passthrough(ff);
struct inode *inode = file_inode(out);
ssize_t ret;
struct backing_file_ctx ctx = {
.cred = ff->cred,
.user_file = out,
.end_write = fuse_file_modified,
};
pr_debug("%s: backing_file=0x%p, pos=%lld, len=%zu, flags=0x%x\n", __func__,
backing_file, ppos ? *ppos : 0, len, flags);
inode_lock(inode);
ret = backing_file_splice_write(pipe, backing_file, ppos, len, flags,
&ctx);
inode_unlock(inode);
return ret;
}
ssize_t fuse_passthrough_mmap(struct file *file, struct vm_area_struct *vma)
{
struct fuse_file *ff = file->private_data;
struct file *backing_file = fuse_file_passthrough(ff);
struct backing_file_ctx ctx = {
.cred = ff->cred,
.user_file = file,
.accessed = fuse_file_accessed,
};
pr_debug("%s: backing_file=0x%p, start=%lu, end=%lu\n", __func__,
backing_file, vma->vm_start, vma->vm_end);
return backing_file_mmap(backing_file, vma, &ctx);
}
struct fuse_backing *fuse_backing_get(struct fuse_backing *fb)
{
if (fb && refcount_inc_not_zero(&fb->count))
return fb;
return NULL;
}
static void fuse_backing_free(struct fuse_backing *fb)
{
pr_debug("%s: fb=0x%p\n", __func__, fb);
if (fb->file)
fput(fb->file);
put_cred(fb->cred);
kfree_rcu(fb, rcu);
}
void fuse_backing_put(struct fuse_backing *fb)
{
if (fb && refcount_dec_and_test(&fb->count))
fuse_backing_free(fb);
}
void fuse_backing_files_init(struct fuse_conn *fc)
{
idr_init(&fc->backing_files_map);
}
static int fuse_backing_id_alloc(struct fuse_conn *fc, struct fuse_backing *fb)
{
int id;
idr_preload(GFP_KERNEL);
spin_lock(&fc->lock);
/* FIXME: xarray might be space inefficient */
id = idr_alloc_cyclic(&fc->backing_files_map, fb, 1, 0, GFP_ATOMIC);
spin_unlock(&fc->lock);
idr_preload_end();
WARN_ON_ONCE(id == 0);
return id;
}
static struct fuse_backing *fuse_backing_id_remove(struct fuse_conn *fc,
int id)
{
struct fuse_backing *fb;
spin_lock(&fc->lock);
fb = idr_remove(&fc->backing_files_map, id);
spin_unlock(&fc->lock);
return fb;
}
static int fuse_backing_id_free(int id, void *p, void *data)
{
struct fuse_backing *fb = p;
WARN_ON_ONCE(refcount_read(&fb->count) != 1);
fuse_backing_free(fb);
return 0;
}
void fuse_backing_files_free(struct fuse_conn *fc)
{
idr_for_each(&fc->backing_files_map, fuse_backing_id_free, NULL);
idr_destroy(&fc->backing_files_map);
}
int fuse_backing_open(struct fuse_conn *fc, struct fuse_backing_map *map)
{
struct file *file;
struct super_block *backing_sb;
struct fuse_backing *fb = NULL;
int res;
pr_debug("%s: fd=%d flags=0x%x\n", __func__, map->fd, map->flags);
/* TODO: relax CAP_SYS_ADMIN once backing files are visible to lsof */
res = -EPERM;
if (!fc->passthrough || !capable(CAP_SYS_ADMIN))
goto out;
res = -EINVAL;
if (map->flags)
goto out;
file = fget(map->fd);
res = -EBADF;
if (!file)
goto out;
res = -EOPNOTSUPP;
if (!file->f_op->read_iter || !file->f_op->write_iter)
goto out_fput;
backing_sb = file_inode(file)->i_sb;
res = -ELOOP;
if (backing_sb->s_stack_depth >= fc->max_stack_depth)
goto out_fput;
fb = kmalloc(sizeof(struct fuse_backing), GFP_KERNEL);
res = -ENOMEM;
if (!fb)
goto out_fput;
fb->file = file;
fb->cred = prepare_creds();
refcount_set(&fb->count, 1);
res = fuse_backing_id_alloc(fc, fb);
if (res < 0) {
fuse_backing_free(fb);
fb = NULL;
}
out:
pr_debug("%s: fb=0x%p, ret=%i\n", __func__, fb, res);
return res;
out_fput:
fput(file);
goto out;
}
int fuse_backing_close(struct fuse_conn *fc, int backing_id)
{
struct fuse_backing *fb = NULL;
int err;
pr_debug("%s: backing_id=%d\n", __func__, backing_id);
/* TODO: relax CAP_SYS_ADMIN once backing files are visible to lsof */
err = -EPERM;
if (!fc->passthrough || !capable(CAP_SYS_ADMIN))
goto out;
err = -EINVAL;
if (backing_id <= 0)
goto out;
err = -ENOENT;
fb = fuse_backing_id_remove(fc, backing_id);
if (!fb)
goto out;
fuse_backing_put(fb);
err = 0;
out:
pr_debug("%s: fb=0x%p, err=%i\n", __func__, fb, err);
return err;
}
/*
* Setup passthrough to a backing file.
*
* Returns an fb object with elevated refcount to be stored in fuse inode.
*/
struct fuse_backing *fuse_passthrough_open(struct file *file,
struct inode *inode,
int backing_id)
{
struct fuse_file *ff = file->private_data;
struct fuse_conn *fc = ff->fm->fc;
struct fuse_backing *fb = NULL;
struct file *backing_file;
int err;
err = -EINVAL;
if (backing_id <= 0)
goto out;
rcu_read_lock();
fb = idr_find(&fc->backing_files_map, backing_id);
fb = fuse_backing_get(fb);
rcu_read_unlock();
err = -ENOENT;
if (!fb)
goto out;
/* Allocate backing file per fuse file to store fuse path */
backing_file = backing_file_open(&file->f_path, file->f_flags,
&fb->file->f_path, fb->cred);
err = PTR_ERR(backing_file);
if (IS_ERR(backing_file)) {
fuse_backing_put(fb);
goto out;
}
err = 0;
ff->passthrough = backing_file;
ff->cred = get_cred(fb->cred);
out:
pr_debug("%s: backing_id=%d, fb=0x%p, backing_file=0x%p, err=%i\n", __func__,
backing_id, fb, ff->passthrough, err);
return err ? ERR_PTR(err) : fb;
}
void fuse_passthrough_release(struct fuse_file *ff, struct fuse_backing *fb)
{
pr_debug("%s: fb=0x%p, backing_file=0x%p\n", __func__,
fb, ff->passthrough);
fput(ff->passthrough);
ff->passthrough = NULL;
put_cred(ff->cred);
ff->cred = NULL;
}

4
fs/fuse/readdir.c
View File

@ -592,15 +592,11 @@ int fuse_readdir(struct file *file, struct dir_context *ctx)
if (fuse_is_bad(inode))
return -EIO;
mutex_lock(&ff->readdir.lock);
err = UNCACHED;
if (ff->open_flags & FOPEN_CACHE_DIR)
err = fuse_readdir_cached(file, ctx);
if (err == UNCACHED)
err = fuse_readdir_uncached(file, ctx);
mutex_unlock(&ff->readdir.lock);
return err;
}

141
fs/fuse/virtio_fs.c
View File

@ -32,6 +32,9 @@
static DEFINE_MUTEX(virtio_fs_mutex);
static LIST_HEAD(virtio_fs_instances);
/* The /sys/fs/virtio_fs/ kset */
static struct kset *virtio_fs_kset;
enum {
VQ_HIPRIO,
VQ_REQUEST
@ -56,7 +59,7 @@ struct virtio_fs_vq {
/* A virtio-fs device instance */
struct virtio_fs {
struct kref refcount;
struct kobject kobj;
struct list_head list; /* on virtio_fs_instances */
char *tag;
struct virtio_fs_vq *vqs;
@ -162,18 +165,40 @@ static inline void dec_in_flight_req(struct virtio_fs_vq *fsvq)
complete(&fsvq->in_flight_zero);
}
static void release_virtio_fs_obj(struct kref *ref)
static ssize_t tag_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct virtio_fs *vfs = container_of(ref, struct virtio_fs, refcount);
struct virtio_fs *fs = container_of(kobj, struct virtio_fs, kobj);
return sysfs_emit(buf, fs->tag);
}
static struct kobj_attribute virtio_fs_tag_attr = __ATTR_RO(tag);
static struct attribute *virtio_fs_attrs[] = {
&virtio_fs_tag_attr.attr,
NULL
};
ATTRIBUTE_GROUPS(virtio_fs);
static void virtio_fs_ktype_release(struct kobject *kobj)
{
struct virtio_fs *vfs = container_of(kobj, struct virtio_fs, kobj);
kfree(vfs->vqs);
kfree(vfs);
}
static const struct kobj_type virtio_fs_ktype = {
.release = virtio_fs_ktype_release,
.sysfs_ops = &kobj_sysfs_ops,
.default_groups = virtio_fs_groups,
};
/* Make sure virtiofs_mutex is held */
static void virtio_fs_put(struct virtio_fs *fs)
{
kref_put(&fs->refcount, release_virtio_fs_obj);
kobject_put(&fs->kobj);
}
static void virtio_fs_fiq_release(struct fuse_iqueue *fiq)
@ -244,25 +269,46 @@ static void virtio_fs_start_all_queues(struct virtio_fs *fs)
}
/* Add a new instance to the list or return -EEXIST if tag name exists*/
static int virtio_fs_add_instance(struct virtio_fs *fs)
static int virtio_fs_add_instance(struct virtio_device *vdev,
struct virtio_fs *fs)
{
struct virtio_fs *fs2;
bool duplicate = false;
int ret;
mutex_lock(&virtio_fs_mutex);
list_for_each_entry(fs2, &virtio_fs_instances, list) {
if (strcmp(fs->tag, fs2->tag) == 0)
duplicate = true;
if (strcmp(fs->tag, fs2->tag) == 0) {
mutex_unlock(&virtio_fs_mutex);
return -EEXIST;
}
}
if (!duplicate)
list_add_tail(&fs->list, &virtio_fs_instances);
/* Use the virtio_device's index as a unique identifier, there is no
* need to allocate our own identifiers because the virtio_fs instance
* is only visible to userspace as long as the underlying virtio_device
* exists.
*/
fs->kobj.kset = virtio_fs_kset;
ret = kobject_add(&fs->kobj, NULL, "%d", vdev->index);
if (ret < 0) {
mutex_unlock(&virtio_fs_mutex);
return ret;
}
ret = sysfs_create_link(&fs->kobj, &vdev->dev.kobj, "device");
if (ret < 0) {
kobject_del(&fs->kobj);
mutex_unlock(&virtio_fs_mutex);
return ret;
}
list_add_tail(&fs->list, &virtio_fs_instances);
mutex_unlock(&virtio_fs_mutex);
if (duplicate)
return -EEXIST;
kobject_uevent(&fs->kobj, KOBJ_ADD);
return 0;
}
@ -275,7 +321,7 @@ static struct virtio_fs *virtio_fs_find_instance(const char *tag)
list_for_each_entry(fs, &virtio_fs_instances, list) {
if (strcmp(fs->tag, tag) == 0) {
kref_get(&fs->refcount);
kobject_get(&fs->kobj);
goto found;
}
}
@ -324,6 +370,16 @@ static int virtio_fs_read_tag(struct virtio_device *vdev, struct virtio_fs *fs)
return -ENOMEM;
memcpy(fs->tag, tag_buf, len);
fs->tag[len] = '\0';
/* While the VIRTIO specification allows any character, newlines are
* awkward on mount(8) command-lines and cause problems in the sysfs
* "tag" attr and uevent TAG= properties. Forbid them.
*/
if (strchr(fs->tag, '\n')) {
dev_dbg(&vdev->dev, "refusing virtiofs tag with newline character\n");
return -EINVAL;
}
return 0;
}
@ -346,7 +402,7 @@ static void virtio_fs_hiprio_done_work(struct work_struct *work)
kfree(req);
dec_in_flight_req(fsvq);
}
} while (!virtqueue_enable_cb(vq) && likely(!virtqueue_is_broken(vq)));
} while (!virtqueue_enable_cb(vq));
spin_unlock(&fsvq->lock);
}
@ -628,7 +684,7 @@ static void virtio_fs_requests_done_work(struct work_struct *work)
list_move_tail(&req->list, &reqs);
spin_unlock(&fpq->lock);
}
} while (!virtqueue_enable_cb(vq) && likely(!virtqueue_is_broken(vq)));
} while (!virtqueue_enable_cb(vq));
spin_unlock(&fsvq->lock);
/* End requests */
@ -872,7 +928,7 @@ static int virtio_fs_probe(struct virtio_device *vdev)
fs = kzalloc(sizeof(*fs), GFP_KERNEL);
if (!fs)
return -ENOMEM;
kref_init(&fs->refcount);
kobject_init(&fs->kobj, &virtio_fs_ktype);
vdev->priv = fs;
ret = virtio_fs_read_tag(vdev, fs);
@ -894,7 +950,7 @@ static int virtio_fs_probe(struct virtio_device *vdev)
*/
virtio_device_ready(vdev);
ret = virtio_fs_add_instance(fs);
ret = virtio_fs_add_instance(vdev, fs);
if (ret < 0)
goto out_vqs;
@ -903,11 +959,10 @@ static int virtio_fs_probe(struct virtio_device *vdev)
out_vqs:
virtio_reset_device(vdev);
virtio_fs_cleanup_vqs(vdev);
kfree(fs->vqs);
out:
vdev->priv = NULL;
kfree(fs);
kobject_put(&fs->kobj);
return ret;
}
@ -931,6 +986,8 @@ static void virtio_fs_remove(struct virtio_device *vdev)
mutex_lock(&virtio_fs_mutex);
/* This device is going away. No one should get new reference */
list_del_init(&fs->list);
sysfs_remove_link(&fs->kobj, "device");
kobject_del(&fs->kobj);
virtio_fs_stop_all_queues(fs);
virtio_fs_drain_all_queues_locked(fs);
virtio_reset_device(vdev);
@ -1517,21 +1574,56 @@ static struct file_system_type virtio_fs_type = {
.kill_sb = virtio_kill_sb,
};
static int virtio_fs_uevent(const struct kobject *kobj, struct kobj_uevent_env *env)
{
const struct virtio_fs *fs = container_of(kobj, struct virtio_fs, kobj);
add_uevent_var(env, "TAG=%s", fs->tag);
return 0;
}
static const struct kset_uevent_ops virtio_fs_uevent_ops = {
.uevent = virtio_fs_uevent,
};
static int __init virtio_fs_sysfs_init(void)
{
virtio_fs_kset = kset_create_and_add("virtiofs", &virtio_fs_uevent_ops,
fs_kobj);
if (!virtio_fs_kset)
return -ENOMEM;
return 0;
}
static void virtio_fs_sysfs_exit(void)
{
kset_unregister(virtio_fs_kset);
virtio_fs_kset = NULL;
}
static int __init virtio_fs_init(void)
{
int ret;
ret = register_virtio_driver(&virtio_fs_driver);
ret = virtio_fs_sysfs_init();
if (ret < 0)
return ret;
ret = register_virtio_driver(&virtio_fs_driver);
if (ret < 0)
goto sysfs_exit;
ret = register_filesystem(&virtio_fs_type);
if (ret < 0) {
unregister_virtio_driver(&virtio_fs_driver);
return ret;
}
if (ret < 0)
goto unregister_virtio_driver;
return 0;
unregister_virtio_driver:
unregister_virtio_driver(&virtio_fs_driver);
sysfs_exit:
virtio_fs_sysfs_exit();
return ret;
}
module_init(virtio_fs_init);
@ -1539,6 +1631,7 @@ static void __exit virtio_fs_exit(void)
{
unregister_filesystem(&virtio_fs_type);
unregister_virtio_driver(&virtio_fs_driver);
virtio_fs_sysfs_exit();
}
module_exit(virtio_fs_exit);

39
include/uapi/linux/fuse.h
View File

@ -211,6 +211,12 @@
* 7.39
* - add FUSE_DIRECT_IO_ALLOW_MMAP
* - add FUSE_STATX and related structures
*
* 7.40
* - add max_stack_depth to fuse_init_out, add FUSE_PASSTHROUGH init flag
* - add backing_id to fuse_open_out, add FOPEN_PASSTHROUGH open flag
* - add FUSE_NO_EXPORT_SUPPORT init flag
* - add FUSE_NOTIFY_RESEND, add FUSE_HAS_RESEND init flag
*/
#ifndef _LINUX_FUSE_H
@ -246,7 +252,7 @@
#define FUSE_KERNEL_VERSION 7
/** Minor version number of this interface */
#define FUSE_KERNEL_MINOR_VERSION 39
#define FUSE_KERNEL_MINOR_VERSION 40
/** The node ID of the root inode */
#define FUSE_ROOT_ID 1
@ -353,6 +359,7 @@ struct fuse_file_lock {
* FOPEN_STREAM: the file is stream-like (no file position at all)
* FOPEN_NOFLUSH: don't flush data cache on close (unless FUSE_WRITEBACK_CACHE)
* FOPEN_PARALLEL_DIRECT_WRITES: Allow concurrent direct writes on the same inode
* FOPEN_PASSTHROUGH: passthrough read/write io for this open file
*/
#define FOPEN_DIRECT_IO (1 << 0)
#define FOPEN_KEEP_CACHE (1 << 1)
@ -361,6 +368,7 @@ struct fuse_file_lock {
#define FOPEN_STREAM (1 << 4)
#define FOPEN_NOFLUSH (1 << 5)
#define FOPEN_PARALLEL_DIRECT_WRITES (1 << 6)
#define FOPEN_PASSTHROUGH (1 << 7)
/**
* INIT request/reply flags
@ -410,6 +418,9 @@ struct fuse_file_lock {
* symlink and mknod (single group that matches parent)
* FUSE_HAS_EXPIRE_ONLY: kernel supports expiry-only entry invalidation
* FUSE_DIRECT_IO_ALLOW_MMAP: allow shared mmap in FOPEN_DIRECT_IO mode.
* FUSE_NO_EXPORT_SUPPORT: explicitly disable export support
* FUSE_HAS_RESEND: kernel supports resending pending requests, and the high bit
* of the request ID indicates resend requests
*/
#define FUSE_ASYNC_READ (1 << 0)
#define FUSE_POSIX_LOCKS (1 << 1)
@ -449,6 +460,9 @@ struct fuse_file_lock {
#define FUSE_CREATE_SUPP_GROUP (1ULL << 34)
#define FUSE_HAS_EXPIRE_ONLY (1ULL << 35)
#define FUSE_DIRECT_IO_ALLOW_MMAP (1ULL << 36)
#define FUSE_PASSTHROUGH (1ULL << 37)
#define FUSE_NO_EXPORT_SUPPORT (1ULL << 38)
#define FUSE_HAS_RESEND (1ULL << 39)
/* Obsolete alias for FUSE_DIRECT_IO_ALLOW_MMAP */
#define FUSE_DIRECT_IO_RELAX FUSE_DIRECT_IO_ALLOW_MMAP
@ -635,6 +649,7 @@ enum fuse_notify_code {
FUSE_NOTIFY_STORE = 4,
FUSE_NOTIFY_RETRIEVE = 5,
FUSE_NOTIFY_DELETE = 6,
FUSE_NOTIFY_RESEND = 7,
FUSE_NOTIFY_CODE_MAX,
};
@ -761,7 +776,7 @@ struct fuse_create_in {
struct fuse_open_out {
uint64_t fh;
uint32_t open_flags;
uint32_t padding;
int32_t backing_id;
};
struct fuse_release_in {
@ -877,7 +892,8 @@ struct fuse_init_out {
uint16_t max_pages;
uint16_t map_alignment;
uint32_t flags2;
uint32_t unused[7];
uint32_t max_stack_depth;
uint32_t unused[6];
};
#define CUSE_INIT_INFO_MAX 4096
@ -960,6 +976,14 @@ struct fuse_fallocate_in {
uint32_t padding;
};
/**
* FUSE request unique ID flag
*
* Indicates whether this is a resend request. The receiver should handle this
* request accordingly.
*/
#define FUSE_UNIQUE_RESEND (1ULL << 63)
struct fuse_in_header {
uint32_t len;
uint32_t opcode;
@ -1049,9 +1073,18 @@ struct fuse_notify_retrieve_in {
uint64_t dummy4;
};
struct fuse_backing_map {
int32_t fd;
uint32_t flags;
uint64_t padding;
};
/* Device ioctls: */
#define FUSE_DEV_IOC_MAGIC 229
#define FUSE_DEV_IOC_CLONE _IOR(FUSE_DEV_IOC_MAGIC, 0, uint32_t)
#define FUSE_DEV_IOC_BACKING_OPEN _IOW(FUSE_DEV_IOC_MAGIC, 1, \
struct fuse_backing_map)
#define FUSE_DEV_IOC_BACKING_CLOSE _IOW(FUSE_DEV_IOC_MAGIC, 2, uint32_t)
struct fuse_lseek_in {
uint64_t fh;