Use the backing file read/write helpers to implement read/write
passthrough to a backing file.
Similar to update size/mtime at the end of fuse_perform_write(),
we need to bump the attr version when we update the inode size,
so extend the ->end_write() callback to report pos and number of
bytes written.
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
fs/backing-file.c | 8 ++--
fs/fuse/file.c | 8 +++-
fs/fuse/fuse_i.h | 3 ++
fs/fuse/passthrough.c | 86 ++++++++++++++++++++++++++++++++++++
fs/overlayfs/file.c | 9 +++-
include/linux/backing-file.h | 2 +-
6 files changed, 107 insertions(+), 9 deletions(-)
diff --git a/fs/backing-file.c b/fs/backing-file.c
index 1601a32e8e6a..133373432b9c 100644
--- a/fs/backing-file.c
+++ b/fs/backing-file.c
@@ -57,7 +57,7 @@ struct backing_aio {
refcount_t ref;
struct kiocb *orig_iocb;
/* used for aio completion */
- void (*end_write)(struct file *);
+ void (*end_write)(struct file *, loff_t, ssize_t);
struct work_struct work;
long res;
};
@@ -88,7 +88,7 @@ static void backing_aio_cleanup(struct backing_aio *aio, long res)
if (iocb->ki_flags & IOCB_WRITE) {
kiocb_end_write(iocb);
if (aio->end_write)
- aio->end_write(orig_iocb->ki_filp);
+ aio->end_write(orig_iocb->ki_filp, iocb->ki_pos, res);
}
orig_iocb->ki_pos = iocb->ki_pos;
@@ -208,7 +208,7 @@ ssize_t backing_file_write_iter(struct file *file, struct iov_iter *iter,
ret = vfs_iter_write(file, iter, &iocb->ki_pos, rwf);
file_end_write(file);
if (ctx->end_write)
- ctx->end_write(ctx->user_file);
+ ctx->end_write(iocb->ki_filp, iocb->ki_pos, ret);
} else {
struct backing_aio *aio;
@@ -274,7 +274,7 @@ ssize_t backing_file_splice_write(struct pipe_inode_info *pipe,
revert_creds(old_cred);
if (ctx->end_write)
- ctx->end_write(ctx->user_file);
+ ctx->end_write(ctx->user_file, ppos ? *ppos : 0, ret);
return ret;
}
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 83a7b16d682d..17964486ba80 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1636,7 +1636,9 @@ 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))
+ if (fuse_file_passthrough(ff))
+ return fuse_passthrough_read_iter(iocb, to);
+ else if (!(ff->open_flags & FOPEN_DIRECT_IO))
return fuse_cache_read_iter(iocb, to);
else
return fuse_direct_read_iter(iocb, to);
@@ -1654,7 +1656,9 @@ 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))
+ if (fuse_file_passthrough(ff))
+ return fuse_passthrough_write_iter(iocb, from);
+ else if (!(ff->open_flags & FOPEN_DIRECT_IO))
return fuse_cache_write_iter(iocb, from);
else
return fuse_direct_write_iter(iocb, from);
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index cb1e2aadf1dc..0a43dc93e376 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -1395,4 +1395,7 @@ static inline struct file *fuse_file_passthrough(struct fuse_file *ff)
#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);
+
#endif /* _FS_FUSE_I_H */
diff --git a/fs/fuse/passthrough.c b/fs/fuse/passthrough.c
index 2c8e68f1c90e..0224f63f8cdf 100644
--- a/fs/fuse/passthrough.c
+++ b/fs/fuse/passthrough.c
@@ -10,6 +10,92 @@
#include <linux/file.h>
#include <linux/backing-file.h>
+static void fuse_file_start_write(struct file *file, loff_t pos, size_t count)
+{
+ struct inode *inode = file_inode(file);
+ struct fuse_inode *fi = get_fuse_inode(inode);
+
+ if (inode->i_size < pos + count)
+ set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
+}
+
+static void fuse_file_end_write(struct file *file, loff_t pos, ssize_t res)
+{
+ struct inode *inode = file_inode(file);
+ struct fuse_inode *fi = get_fuse_inode(inode);
+
+ fuse_write_update_attr(inode, pos, res);
+ clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
+}
+
+static void fuse_file_accessed(struct file *file)
+{
+ struct inode *inode = file_inode(file);
+ struct fuse_file *ff = file->private_data;
+ struct file *backing_file = fuse_file_passthrough(ff);
+ struct inode *backing_inode = file_inode(backing_file);
+
+ /* Mimic atime update policy of backing inode, not the actual value */
+ if (!timespec64_equal(&backing_inode->i_atime, &inode->i_atime))
+ fuse_invalidate_atime(inode);
+}
+
+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_end_write,
+ };
+
+ 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);
+ fuse_file_start_write(file, iocb->ki_pos, count);
+ ret = backing_file_write_iter(backing_file, iter, iocb, iocb->ki_flags,
+ &ctx);
+ inode_unlock(inode);
+
+ return ret;
+}
+
struct fuse_backing *fuse_backing_get(struct fuse_backing *fb)
{
if (fb && refcount_inc_not_zero(&fb->count))
diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index 034b8088c408..3659c7f340e5 100644
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -232,6 +232,11 @@ static void ovl_file_modified(struct file *file)
ovl_copyattr(file_inode(file));
}
+static void ovl_file_end_write(struct file *file, loff_t pos, ssize_t res)
+{
+ ovl_file_modified(file);
+}
+
static void ovl_file_accessed(struct file *file)
{
struct inode *inode, *upperinode;
@@ -292,7 +297,7 @@ static ssize_t ovl_write_iter(struct kiocb *iocb, struct iov_iter *iter)
struct backing_file_ctx ctx = {
.cred = ovl_creds(inode->i_sb),
.user_file = file,
- .end_write = ovl_file_modified,
+ .end_write = ovl_file_end_write,
};
if (!iov_iter_count(iter))
@@ -365,7 +370,7 @@ static ssize_t ovl_splice_write(struct pipe_inode_info *pipe, struct file *out,
struct backing_file_ctx ctx = {
.cred = ovl_creds(inode->i_sb),
.user_file = out,
- .end_write = ovl_file_modified,
+ .end_write = ovl_file_end_write,
};
inode_lock(inode);
diff --git a/include/linux/backing-file.h b/include/linux/backing-file.h
index 3f1fe1774f1b..98e0b6c30193 100644
--- a/include/linux/backing-file.h
+++ b/include/linux/backing-file.h
@@ -16,7 +16,7 @@ struct backing_file_ctx {
const struct cred *cred;
struct file *user_file;
void (*accessed)(struct file *);
- void (*end_write)(struct file *);
+ void (*end_write)(struct file *, loff_t, ssize_t);
};
struct file *backing_file_open(const struct path *user_path, int flags,
--
2.34.1
