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From: Vivek Goyal <vgoyal@redhat.com>
To: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	kvm@vger.kernel.org
Cc: vgoyal@redhat.com, miklos@szeredi.hu, stefanha@redhat.com,
	dgilbert@redhat.com, sweil@redhat.com, swhiteho@redhat.com
Subject: [PATCH 28/52] Do fallocate() to grow file before mapping for file growing writes
Date: Mon, 10 Dec 2018 12:12:54 -0500
Message-ID: <20181210171318.16998-29-vgoyal@redhat.com> (raw)
In-Reply-To: <20181210171318.16998-1-vgoyal@redhat.com>

How to handle file growing writes. For now, this patch does fallocate() to
grow file and then map it using dax. We need to figure out what's the best
way to handle it.

This patch does fallocate() and setup mapping operations in
fuse_dax_write_iter(), instead of iomap_begin(). I don't have access to file
pointer needed to send a message to fuse daemon in iomap_begin().

Dave Chinner has expressed concers with this approach as this is not
atomic. If guest crashes after falloc() but before data was written,
user will think that filesystem lost its data. So this is still an
outstanding issue.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
---
 fs/fuse/file.c | 71 +++++++++++++++++++++++++++++++++++++++++++++-------------
 1 file changed, 55 insertions(+), 16 deletions(-)

diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 94ad76382a6f..41d773ba2c72 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -28,6 +28,9 @@ INTERVAL_TREE_DEFINE(struct fuse_dax_mapping,
                      rb, __u64, __subtree_last,
                      START, LAST, static inline, fuse_dax_interval_tree);
 
+static long __fuse_file_fallocate(struct file *file, int mode,
+					loff_t offset, loff_t length);
+
 static int fuse_send_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
 			  int opcode, struct fuse_open_out *outargp)
 {
@@ -1819,6 +1822,22 @@ static ssize_t fuse_dax_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	/* TODO file_update_time() but we don't want metadata I/O */
 
 	/* TODO handle growing the file */
+	/* Grow file here if need be. iomap_begin() does not have access
+	 * to file pointer
+	 */
+	if (iov_iter_rw(from) == WRITE &&
+	    ((iocb->ki_pos + iov_iter_count(from)) > i_size_read(inode))) {
+		ret = __fuse_file_fallocate(iocb->ki_filp, 0, iocb->ki_pos,
+						iov_iter_count(from));
+		if (ret < 0) {
+			printk("fallocate(offset=0x%llx length=0x%lx)"
+			" failed. err=%ld\n", iocb->ki_pos,
+			iov_iter_count(from), ret);
+			goto out;
+		}
+		pr_debug("fallocate(offset=0x%llx length=0x%lx)"
+		" succeed. ret=%ld\n", iocb->ki_pos, iov_iter_count(from), ret);
+	}
 
 	ret = dax_iomap_rw(iocb, from, &fuse_iomap_ops);
 
@@ -3331,8 +3350,12 @@ fuse_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 	return ret;
 }
 
-static long fuse_file_fallocate(struct file *file, int mode, loff_t offset,
-				loff_t length)
+/*
+ * This variant does not take any inode lock and if locking is required,
+ * caller is supposed to hold lock
+ */
+static long __fuse_file_fallocate(struct file *file, int mode,
+					loff_t offset, loff_t length)
 {
 	struct fuse_file *ff = file->private_data;
 	struct inode *inode = file_inode(file);
@@ -3346,8 +3369,6 @@ static long fuse_file_fallocate(struct file *file, int mode, loff_t offset,
 		.mode = mode
 	};
 	int err;
-	bool lock_inode = !(mode & FALLOC_FL_KEEP_SIZE) ||
-			   (mode & FALLOC_FL_PUNCH_HOLE);
 
 	if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
 		return -EOPNOTSUPP;
@@ -3355,17 +3376,13 @@ static long fuse_file_fallocate(struct file *file, int mode, loff_t offset,
 	if (fc->no_fallocate)
 		return -EOPNOTSUPP;
 
-	if (lock_inode) {
-		inode_lock(inode);
-		if (mode & FALLOC_FL_PUNCH_HOLE) {
-			loff_t endbyte = offset + length - 1;
-			err = filemap_write_and_wait_range(inode->i_mapping,
-							   offset, endbyte);
-			if (err)
-				goto out;
-
-			fuse_sync_writes(inode);
-		}
+	if (mode & FALLOC_FL_PUNCH_HOLE) {
+		loff_t endbyte = offset + length - 1;
+		err = filemap_write_and_wait_range(inode->i_mapping, offset,
+							endbyte);
+		if (err)
+			goto out;
+		fuse_sync_writes(inode);
 	}
 
 	if (!(mode & FALLOC_FL_KEEP_SIZE))
@@ -3401,9 +3418,31 @@ static long fuse_file_fallocate(struct file *file, int mode, loff_t offset,
 	if (!(mode & FALLOC_FL_KEEP_SIZE))
 		clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
 
+	return err;
+}
+
+static long fuse_file_fallocate(struct file *file, int mode, loff_t offset,
+				loff_t length)
+{
+	struct fuse_file *ff = file->private_data;
+	struct inode *inode = file_inode(file);
+	struct fuse_conn *fc = ff->fc;
+	int err;
+	bool lock_inode = !(mode & FALLOC_FL_KEEP_SIZE) ||
+			   (mode & FALLOC_FL_PUNCH_HOLE);
+
+	if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
+		return -EOPNOTSUPP;
+
+	if (fc->no_fallocate)
+		return -EOPNOTSUPP;
+
 	if (lock_inode)
-		inode_unlock(inode);
+		inode_lock(inode);
 
+	err = __fuse_file_fallocate(file, mode, offset, length);
+	if (lock_inode)
+		inode_unlock(inode);
 	return err;
 }
 
-- 
2.13.6


  parent reply index

Thread overview: 98+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-12-10 17:12 [PATCH 00/52] [RFC] virtio-fs: shared file system for virtual machines Vivek Goyal
2018-12-10 17:12 ` [PATCH 01/52] fuse: add skeleton virtio_fs.ko module Vivek Goyal
2018-12-10 17:12 ` [PATCH 02/52] fuse: add probe/remove virtio driver Vivek Goyal
2018-12-10 17:12 ` [PATCH 03/52] fuse: rely on mutex_unlock() barrier instead of fput() Vivek Goyal
2018-12-10 17:12 ` [PATCH 04/52] fuse: extract fuse_fill_super_common() Vivek Goyal
2018-12-10 17:12 ` [PATCH 05/52] virtio_fs: get mount working Vivek Goyal
2018-12-10 17:12 ` [PATCH 06/52] fuse: export fuse_end_request() Vivek Goyal
2018-12-10 17:12 ` [PATCH 07/52] fuse: export fuse_len_args() Vivek Goyal
2018-12-10 17:12 ` [PATCH 08/52] fuse: add fuse_iqueue_ops callbacks Vivek Goyal
2018-12-10 17:12 ` [PATCH 09/52] fuse: process requests queues Vivek Goyal
2018-12-10 17:12 ` [PATCH 10/52] fuse: export fuse_get_unique() Vivek Goyal
2018-12-10 17:12 ` [PATCH 11/52] fuse: implement FUSE_FORGET for virtio-fs Vivek Goyal
2018-12-10 17:12 ` [PATCH 12/52] virtio_fs: Set up dax_device Vivek Goyal
2018-12-10 17:12 ` [PATCH 13/52] dax: remove block device dependencies Vivek Goyal
2018-12-10 17:12 ` [PATCH 14/52] fuse: add fuse_conn->dax_dev field Vivek Goyal
2018-12-10 17:12 ` [PATCH 15/52] fuse: map virtio_fs DAX window BAR Vivek Goyal
2018-12-12 16:37   ` Christian Borntraeger
2018-12-13 11:55     ` Stefan Hajnoczi
2018-12-13 16:06   ` kbuild test robot
2018-12-13 19:55   ` Dan Williams
2018-12-13 20:09     ` Dr. David Alan Gilbert
2018-12-13 20:15       ` Dan Williams
2018-12-13 20:40         ` Vivek Goyal
2018-12-13 21:18           ` Vivek Goyal
2018-12-14 10:09             ` Dr. David Alan Gilbert
2018-12-10 17:12 ` [PATCH 16/52] virtio-fs: Add VIRTIO_PCI_CAP_SHARED_MEMORY_CFG and utility to find them Vivek Goyal
2018-12-12 16:36   ` [PATCH] virtio-fs: fix semicolon.cocci warnings kbuild test robot
2018-12-12 16:36   ` [PATCH 16/52] virtio-fs: Add VIRTIO_PCI_CAP_SHARED_MEMORY_CFG and utility to find them kbuild test robot
2018-12-10 17:12 ` [PATCH 17/52] virtio-fs: Retrieve shm capabilities for cache Vivek Goyal
2018-12-10 17:12 ` [PATCH 18/52] virtio-fs: Map cache using the values from the capabilities Vivek Goyal
2018-12-13  9:10   ` David Hildenbrand
2018-12-13  9:13     ` Dr. David Alan Gilbert
2018-12-13  9:34       ` David Hildenbrand
2018-12-13 10:00         ` Dr. David Alan Gilbert
2018-12-13 11:26           ` David Hildenbrand
2018-12-13 12:15             ` Dr. David Alan Gilbert
2018-12-13 12:24               ` David Hildenbrand
2018-12-13 12:38                 ` Cornelia Huck
2018-12-14 13:44                   ` Stefan Hajnoczi
2018-12-14 13:50                     ` Cornelia Huck
2018-12-14 14:06                       ` Dr. David Alan Gilbert
2018-12-17 11:25                       ` Stefan Hajnoczi
2018-12-17 10:53                     ` David Hildenbrand
2018-12-17 14:56                       ` Stefan Hajnoczi
2018-12-18 17:13                         ` Cornelia Huck
2018-12-18 17:25                           ` David Hildenbrand
2019-01-02 10:24                             ` Stefan Hajnoczi
2019-03-17  0:33   ` Liu Bo
2019-03-20 10:42     ` Dr. David Alan Gilbert
2019-03-17  0:35   ` [PATCH] virtio-fs: fix multiple tag support Liu Bo
2019-03-19 20:26     ` Vivek Goyal
2019-03-20  2:04       ` Liu Bo
2018-12-10 17:12 ` [PATCH 19/52] virito-fs: Make dax optional Vivek Goyal
2018-12-10 17:12 ` [PATCH 20/52] Limit number of pages returned by direct_access() Vivek Goyal
2018-12-10 17:12 ` [PATCH 21/52] fuse: Introduce fuse_dax_mapping Vivek Goyal
2018-12-10 17:12 ` [PATCH 22/52] Create a list of free memory ranges Vivek Goyal
2018-12-11 17:44   ` kbuild test robot
2018-12-15 19:22   ` kbuild test robot
2018-12-10 17:12 ` [PATCH 23/52] fuse: simplify fuse_fill_super_common() calling Vivek Goyal
2018-12-10 17:12 ` [PATCH 24/52] fuse: Introduce setupmapping/removemapping commands Vivek Goyal
2018-12-10 17:12 ` [PATCH 25/52] Introduce interval tree basic data structures Vivek Goyal
2018-12-10 17:12 ` [PATCH 26/52] fuse: Implement basic DAX read/write support commands Vivek Goyal
2018-12-10 17:12 ` [PATCH 27/52] fuse: Maintain a list of busy elements Vivek Goyal
2018-12-10 17:12 ` Vivek Goyal [this message]
2018-12-11  6:13   ` [PATCH 28/52] Do fallocate() to grow file before mapping for file growing writes kbuild test robot
2018-12-11  6:20   ` kbuild test robot
2018-12-10 17:12 ` [PATCH 29/52] fuse: add DAX mmap support Vivek Goyal
2018-12-10 17:12 ` [PATCH 30/52] fuse: delete dentry if timeout is zero Vivek Goyal
2018-12-10 17:12 ` [PATCH 31/52] dax: Pass dax_dev to dax_writeback_mapping_range() Vivek Goyal
2018-12-11  6:12   ` kbuild test robot
2018-12-11 17:38   ` kbuild test robot
2018-12-10 17:12 ` [PATCH 32/52] fuse: Define dax address space operations Vivek Goyal
2018-12-10 17:12 ` [PATCH 33/52] fuse, dax: Take ->i_mmap_sem lock during dax page fault Vivek Goyal
2018-12-10 17:13 ` [PATCH 34/52] fuse: Add logic to free up a memory range Vivek Goyal
2018-12-10 17:13 ` [PATCH 35/52] fuse: Add logic to do direct reclaim of memory Vivek Goyal
2018-12-10 17:13 ` [PATCH 36/52] fuse: Kick worker when free memory drops below 20% of total ranges Vivek Goyal
2018-12-10 17:13 ` [PATCH 37/52] fuse: multiplex cached/direct_io/dax file operations Vivek Goyal
2018-12-10 17:13 ` [PATCH 38/52] Dispatch FORGET requests later instead of dropping them Vivek Goyal
2018-12-10 17:13 ` [PATCH 39/52] Release file in process context Vivek Goyal
2018-12-10 17:13 ` [PATCH 40/52] fuse: Do not block on inode lock while freeing memory range Vivek Goyal
2018-12-10 17:13 ` [PATCH 41/52] fuse: Reschedule dax free work if too many EAGAIN attempts Vivek Goyal
2018-12-10 17:13 ` [PATCH 42/52] fuse: Wait for memory ranges to become free Vivek Goyal
2018-12-10 17:13 ` [PATCH 43/52] fuse: Take inode lock for dax inode truncation Vivek Goyal
2018-12-10 17:13 ` [PATCH 44/52] fuse: Clear setuid bit even in direct I/O path Vivek Goyal
2018-12-10 17:13 ` [PATCH 45/52] virtio: Free fuse devices on umount Vivek Goyal
2018-12-10 17:13 ` [PATCH 46/52] virtio-fs: Retrieve shm capabilities for version table Vivek Goyal
2018-12-10 17:13 ` [PATCH 47/52] virtio-fs: Map using the values from the capabilities Vivek Goyal
2018-12-10 17:13 ` [PATCH 48/52] virtio-fs: pass version table pointer to fuse Vivek Goyal
2018-12-10 17:13 ` [PATCH 49/52] fuse: don't crash if version table is NULL Vivek Goyal
2018-12-10 17:13 ` [PATCH 50/52] fuse: add shared version support (virtio-fs only) Vivek Goyal
2018-12-10 17:13 ` [PATCH 51/52] fuse: shared version cleanups Vivek Goyal
2018-12-10 17:13 ` [PATCH 52/52] fuse: fix fuse_permission() for the default_permissions case Vivek Goyal
2018-12-19 21:25   ` kbuild test robot
2018-12-11 12:54 ` [PATCH 00/52] [RFC] virtio-fs: shared file system for virtual machines Stefan Hajnoczi
2018-12-12 20:30 ` Konrad Rzeszutek Wilk
2018-12-12 21:22   ` Vivek Goyal
2019-02-12 15:56 ` Aneesh Kumar K.V
2019-02-12 18:57   ` Vivek Goyal

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