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Date:   Mon, 21 Nov 2022 18:15:25 -0800
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Subject: [RFC PATCH v2 10/21] fuse-bpf: Add support for fallocate
From:   Daniel Rosenberg <drosen@google.com>
To:     Miklos Szeredi <miklos@szeredi.hu>
Cc:     Amir Goldstein <amir73il@gmail.com>, linux-kernel@vger.kernel.org,
        linux-fsdevel@vger.kernel.org, linux-unionfs@vger.kernel.org,
        bpf@vger.kernel.org, kernel-team@android.com,
        Daniel Rosenberg <drosen@google.com>,
        Paul Lawrence <paullawrence@google.com>
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Precedence: bulk

Signed-off-by: Daniel Rosenberg <drosen@google.com>
Signed-off-by: Paul Lawrence <paullawrence@google.com>
---
 fs/fuse/backing.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++
 fs/fuse/file.c    |  3 +++
 fs/fuse/fuse_i.h  |  6 +++++
 3 files changed, 67 insertions(+)

diff --git a/fs/fuse/backing.c b/fs/fuse/backing.c
index 76f48872ed35..51aadeb1b7dc 100644
--- a/fs/fuse/backing.c
+++ b/fs/fuse/backing.c
@@ -330,6 +330,64 @@ ssize_t fuse_backing_mmap(struct file *file, struct vm_area_struct *vma)
 	return ret;
 }
 
+static int fuse_file_fallocate_initialize_in(struct fuse_args *fa,
+					     struct fuse_fallocate_in *ffi,
+					     struct file *file, int mode, loff_t offset, loff_t length)
+{
+	struct fuse_file *ff = file->private_data;
+
+	*ffi = (struct fuse_fallocate_in) {
+		.fh = ff->fh,
+		.offset = offset,
+		.length = length,
+		.mode = mode,
+	};
+
+	*fa = (struct fuse_args) {
+		.opcode = FUSE_FALLOCATE,
+		.nodeid = ff->nodeid,
+		.in_numargs = 1,
+		.in_args[0].size = sizeof(*ffi),
+		.in_args[0].value = ffi,
+	};
+
+	return 0;
+}
+
+static int fuse_file_fallocate_initialize_out(struct fuse_args *fa,
+					      struct fuse_fallocate_in *ffi,
+					      struct file *file, int mode, loff_t offset, loff_t length)
+{
+	return 0;
+}
+
+static int fuse_file_fallocate_backing(struct fuse_args *fa, int *out,
+				       struct file *file, int mode, loff_t offset, loff_t length)
+{
+	const struct fuse_fallocate_in *ffi = fa->in_args[0].value;
+	struct fuse_file *ff = file->private_data;
+
+	*out = vfs_fallocate(ff->backing_file, ffi->mode, ffi->offset,
+			     ffi->length);
+	return 0;
+}
+
+static int fuse_file_fallocate_finalize(struct fuse_args *fa, int *out,
+					struct file *file, int mode, loff_t offset, loff_t length)
+{
+	return 0;
+}
+
+int fuse_bpf_file_fallocate(int *out, struct inode *inode, struct file *file, int mode, loff_t offset, loff_t length)
+{
+	return fuse_bpf_backing(inode, struct fuse_fallocate_in, out,
+				fuse_file_fallocate_initialize_in,
+				fuse_file_fallocate_initialize_out,
+				fuse_file_fallocate_backing,
+				fuse_file_fallocate_finalize,
+				file, mode, offset, length);
+}
+
 /*******************************************************************************
  * Directory operations after here                                             *
  ******************************************************************************/
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index e90b3e2d5452..ab3cd43556e0 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -2997,6 +2997,9 @@ static long fuse_file_fallocate(struct file *file, int mode, loff_t offset,
 
 	bool block_faults = FUSE_IS_DAX(inode) && lock_inode;
 
+	if (fuse_bpf_file_fallocate(&err, inode, file, mode, offset, length))
+		return err;
+
 	if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
 		     FALLOC_FL_ZERO_RANGE))
 		return -EOPNOTSUPP;
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 108c2ea15a49..4351dbc7f10d 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -1401,6 +1401,7 @@ int parse_fuse_bpf_entry(struct fuse_bpf_entry *fbe, int num_entries);
 #ifdef CONFIG_FUSE_BPF
 
 int fuse_bpf_lseek(loff_t *out, struct inode *inode, struct file *file, loff_t offset, int whence);
+int fuse_bpf_file_fallocate(int *out, struct inode *inode, struct file *file, int mode, loff_t offset, loff_t length);
 int fuse_bpf_lookup(struct dentry **out, struct inode *dir, struct dentry *entry, unsigned int flags);
 int fuse_bpf_access(int *out, struct inode *inode, int mask);
 
@@ -1411,6 +1412,11 @@ static inline int fuse_bpf_lseek(loff_t *out, struct inode *inode, struct file *
 	return 0;
 }
 
+static inline int fuse_bpf_file_fallocate(int *out, struct inode *inode, struct file *file, int mode, loff_t offset, loff_t length)
+{
+	return 0;
+}
+
 static inline int fuse_bpf_lookup(struct dentry **out, struct inode *dir, struct dentry *entry, unsigned int flags)
 {
 	return 0;
-- 
2.38.1.584.g0f3c55d4c2-goog