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-rw-r--r--fs/fuse/file.c9
-rw-r--r--fs/fuse/fuse_i.h35
-rw-r--r--fs/fuse/iomode.c60
-rw-r--r--fs/fuse/passthrough.c59
4 files changed, 155 insertions, 8 deletions
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 47c1ecab7b5c..6fad381f3beb 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -295,6 +295,9 @@ static void fuse_prepare_release(struct fuse_inode *fi, struct fuse_file *ff,
struct fuse_conn *fc = ff->fm->fc;
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)) {
spin_lock(&fi->lock);
@@ -1374,7 +1377,7 @@ static void fuse_dio_lock(struct kiocb *iocb, struct iov_iter *from,
* have raced, so check it again.
*/
if (fuse_io_past_eof(iocb, from) ||
- fuse_file_uncached_io_start(inode, ff) != 0) {
+ fuse_file_uncached_io_start(inode, ff, NULL) != 0) {
inode_unlock_shared(inode);
inode_lock(inode);
*exclusive = true;
@@ -2527,6 +2530,10 @@ static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
if (FUSE_IS_DAX(file_inode(file)))
return fuse_dax_mmap(file, vma);
+ /* TODO: implement mmap to backing file */
+ if (fuse_file_passthrough(ff))
+ 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.
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 40e94ef3d093..8fbf30fe3c3d 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -269,6 +269,12 @@ struct fuse_file {
/** 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;
};
@@ -1394,7 +1400,7 @@ int fuse_fileattr_set(struct mnt_idmap *idmap,
/* 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);
+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);
@@ -1426,11 +1432,38 @@ static inline struct fuse_backing *fuse_inode_backing_set(struct fuse_inode *fi,
#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
+}
+
#endif /* _FS_FUSE_I_H */
diff --git a/fs/fuse/iomode.c b/fs/fuse/iomode.c
index 2161bdf91db2..c653ddcf0578 100644
--- a/fs/fuse/iomode.c
+++ b/fs/fuse/iomode.c
@@ -17,7 +17,7 @@
*/
static inline bool fuse_is_io_cache_wait(struct fuse_inode *fi)
{
- return READ_ONCE(fi->iocachectr) < 0;
+ return READ_ONCE(fi->iocachectr) < 0 && !fuse_inode_backing(fi);
}
/*
@@ -45,6 +45,17 @@ int fuse_file_cached_io_start(struct inode *inode, struct fuse_file *ff)
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;
@@ -71,12 +82,19 @@ static void fuse_file_cached_io_end(struct inode *inode, struct fuse_file *ff)
}
/* Start strictly uncached io mode where cache access is not allowed */
-int fuse_file_uncached_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)
{
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;
@@ -84,6 +102,14 @@ int fuse_file_uncached_io_start(struct inode *inode, struct fuse_file *ff)
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;
@@ -92,15 +118,20 @@ unlock:
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)
+ 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);
}
/*
@@ -118,6 +149,7 @@ 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 */
@@ -125,11 +157,18 @@ static int fuse_file_passthrough_open(struct inode *inode, struct file *file)
(ff->open_flags & ~FOPEN_PASSTHROUGH_MASK))
return -EINVAL;
- /* TODO: implement backing file open */
- return -EOPNOTSUPP;
+ 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);
+ err = fuse_file_uncached_io_start(inode, ff, fb);
+ if (!err)
+ return 0;
+
+ fuse_passthrough_release(ff, fb);
+ fuse_backing_put(fb);
return err;
}
@@ -138,6 +177,7 @@ static int fuse_file_passthrough_open(struct inode *inode, struct file *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;
/*
@@ -148,6 +188,14 @@ int fuse_file_io_open(struct file *file, struct inode *inode)
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))
diff --git a/fs/fuse/passthrough.c b/fs/fuse/passthrough.c
index 7ec92a54c2e0..dc054d2ab13e 100644
--- a/fs/fuse/passthrough.c
+++ b/fs/fuse/passthrough.c
@@ -8,6 +8,7 @@
#include "fuse_i.h"
#include <linux/file.h>
+#include <linux/backing-file.h>
struct fuse_backing *fuse_backing_get(struct fuse_backing *fb)
{
@@ -164,3 +165,61 @@ out:
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;
+}
generated by cgit v1.2.3-70-g09d2 (git 2.47.1) at 2025-02-07 09:36:05 +0000