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From: Omar Sandoval <osandov@osandov.com>
To: linux-btrfs@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org
Subject: [PATCH 1/9] btrfs: send: get rid of i_size logic in send_write()
Date: Fri, 21 Aug 2020 00:39:51 -0700	[thread overview]
Message-ID: <16f28691ff66e8aeb280532cc146c8ee49d6cda4.1597994106.git.osandov@osandov.com> (raw)
In-Reply-To: <cover.1597994106.git.osandov@osandov.com>

From: Omar Sandoval <osandov@fb.com>

send_write()/fill_read_buf() have some logic for avoiding reading past
i_size. However, everywhere that we call
send_write()/send_extent_data(), we've already clamped the length down
to i_size. Get rid of the i_size handling, which simplifies the next
change.

Signed-off-by: Omar Sandoval <osandov@fb.com>
---
 fs/btrfs/send.c | 37 ++++++++++---------------------------
 1 file changed, 10 insertions(+), 27 deletions(-)

diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index 7c7c09fc65e8..8af5e867e4ca 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -4794,7 +4794,7 @@ static int process_all_new_xattrs(struct send_ctx *sctx)
 	return ret;
 }
 
-static ssize_t fill_read_buf(struct send_ctx *sctx, u64 offset, u32 len)
+static int fill_read_buf(struct send_ctx *sctx, u64 offset, u32 len)
 {
 	struct btrfs_root *root = sctx->send_root;
 	struct btrfs_fs_info *fs_info = root->fs_info;
@@ -4804,21 +4804,13 @@ static ssize_t fill_read_buf(struct send_ctx *sctx, u64 offset, u32 len)
 	pgoff_t index = offset >> PAGE_SHIFT;
 	pgoff_t last_index;
 	unsigned pg_offset = offset_in_page(offset);
-	ssize_t ret = 0;
+	int ret = 0;
+	size_t read = 0;
 
 	inode = btrfs_iget(fs_info->sb, sctx->cur_ino, root);
 	if (IS_ERR(inode))
 		return PTR_ERR(inode);
 
-	if (offset + len > i_size_read(inode)) {
-		if (offset > i_size_read(inode))
-			len = 0;
-		else
-			len = offset - i_size_read(inode);
-	}
-	if (len == 0)
-		goto out;
-
 	last_index = (offset + len - 1) >> PAGE_SHIFT;
 
 	/* initial readahead */
@@ -4859,16 +4851,15 @@ static ssize_t fill_read_buf(struct send_ctx *sctx, u64 offset, u32 len)
 		}
 
 		addr = kmap(page);
-		memcpy(sctx->read_buf + ret, addr + pg_offset, cur_len);
+		memcpy(sctx->read_buf + read, addr + pg_offset, cur_len);
 		kunmap(page);
 		unlock_page(page);
 		put_page(page);
 		index++;
 		pg_offset = 0;
 		len -= cur_len;
-		ret += cur_len;
+		read += cur_len;
 	}
-out:
 	iput(inode);
 	return ret;
 }
@@ -4882,7 +4873,6 @@ static int send_write(struct send_ctx *sctx, u64 offset, u32 len)
 	struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
 	int ret = 0;
 	struct fs_path *p;
-	ssize_t num_read = 0;
 
 	p = fs_path_alloc();
 	if (!p)
@@ -4890,12 +4880,9 @@ static int send_write(struct send_ctx *sctx, u64 offset, u32 len)
 
 	btrfs_debug(fs_info, "send_write offset=%llu, len=%d", offset, len);
 
-	num_read = fill_read_buf(sctx, offset, len);
-	if (num_read <= 0) {
-		if (num_read < 0)
-			ret = num_read;
+	ret = fill_read_buf(sctx, offset, len);
+	if (ret < 0)
 		goto out;
-	}
 
 	ret = begin_cmd(sctx, BTRFS_SEND_C_WRITE);
 	if (ret < 0)
@@ -4907,16 +4894,14 @@ static int send_write(struct send_ctx *sctx, u64 offset, u32 len)
 
 	TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
 	TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset);
-	TLV_PUT(sctx, BTRFS_SEND_A_DATA, sctx->read_buf, num_read);
+	TLV_PUT(sctx, BTRFS_SEND_A_DATA, sctx->read_buf, len);
 
 	ret = send_cmd(sctx);
 
 tlv_put_failure:
 out:
 	fs_path_free(p);
-	if (ret < 0)
-		return ret;
-	return num_read;
+	return ret;
 }
 
 /*
@@ -5095,9 +5080,7 @@ static int send_extent_data(struct send_ctx *sctx,
 		ret = send_write(sctx, offset + sent, size);
 		if (ret < 0)
 			return ret;
-		if (!ret)
-			break;
-		sent += ret;
+		sent += size;
 	}
 	return 0;
 }
-- 
2.28.0


  reply	other threads:[~2020-08-21  7:40 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-21  7:39 [PATCH 0/9] btrfs: implement send/receive of compressed extents without decompressing Omar Sandoval
2020-08-21  7:39 ` Omar Sandoval [this message]
2020-08-21 17:26   ` [PATCH 1/9] btrfs: send: get rid of i_size logic in send_write() Filipe Manana
2020-08-24 17:39   ` Josef Bacik
2020-08-21  7:39 ` [PATCH 2/9] btrfs: send: avoid copying file data Omar Sandoval
2020-08-21 17:29   ` Filipe Manana
2020-08-24 21:34     ` Omar Sandoval
2020-08-24 17:47   ` Josef Bacik
2020-09-11 14:13   ` David Sterba
2020-09-14 22:04     ` Omar Sandoval
2020-09-15  8:14       ` David Sterba
2020-08-21  7:39 ` [PATCH 3/9] btrfs: send: use btrfs_file_extent_end() in send_write_or_clone() Omar Sandoval
2020-08-21 17:30   ` Filipe Manana
2020-08-21  7:39 ` [PATCH 4/9] btrfs: add send_stream_version attribute to sysfs Omar Sandoval
2020-08-21  7:39 ` [PATCH 5/9] btrfs: add send stream v2 definitions Omar Sandoval
2020-08-24 17:49   ` Josef Bacik
2020-08-21  7:39 ` [PATCH 6/9] btrfs: send: write larger chunks when using stream v2 Omar Sandoval
2020-08-24 17:57   ` Josef Bacik
2020-08-21  7:39 ` [PATCH 7/9] btrfs: send: allocate send buffer with alloc_page() and vmap() for v2 Omar Sandoval
2020-08-21  7:39 ` [PATCH 8/9] btrfs: send: send compressed extents with encoded writes Omar Sandoval
2020-08-24 17:32   ` Josef Bacik
2020-08-24 17:52     ` Omar Sandoval
2020-08-21  7:39 ` [PATCH 9/9] btrfs: send: enable support for stream v2 and compressed writes Omar Sandoval
2020-08-21  7:40 ` [PATCH 01/11] btrfs-progs: receive: support v2 send stream larger tlv_len Omar Sandoval
2020-08-21  7:40 ` [PATCH 02/11] btrfs-progs: receive: dynamically allocate sctx->read_buf Omar Sandoval
2020-08-21  7:40 ` [PATCH 03/11] btrfs-progs: receive: support v2 send stream DATA tlv format Omar Sandoval
2020-08-21  7:40 ` [PATCH 04/11] btrfs-progs: receive: add send stream v2 cmds and attrs to send.h Omar Sandoval
2020-08-21  7:40 ` [PATCH 05/11] btrfs-progs: receive: add stub implementation for pwritev2 Omar Sandoval
2020-08-21  7:40 ` [PATCH 06/11] btrfs-progs: receive: process encoded_write commands Omar Sandoval
2020-08-21  7:40 ` [PATCH 07/11] btrfs-progs: receive: encoded_write fallback to explicit decode and write Omar Sandoval
2020-08-21  7:40 ` [PATCH 08/11] btrfs-progs: receive: process fallocate commands Omar Sandoval
2020-08-21  7:40 ` [PATCH 09/11] btrfs-progs: receive: process setflags ioctl commands Omar Sandoval
2020-08-21  7:40 ` [PATCH 10/11] btrfs-progs: send: stream v2 ioctl flags Omar Sandoval
2020-08-21  7:40 ` [PATCH 11/11] btrfs-progs: receive: add tests for basic encoded_write send/receive Omar Sandoval
2020-08-24 19:57 ` [PATCH 0/9] btrfs: implement send/receive of compressed extents without decompressing David Sterba
2020-08-24 22:16   ` Omar Sandoval
2020-09-10 11:28 ` David Sterba

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