UDF: Add support for O_DIRECT

Add support for the O_DIRECT flag. There are two cases to deal with: 1. Small files stored in the ICB (inode control block?): just return 0 from the new udf_adinicb_direct_IO() handler to fall back to buffered I/O. 2. Larger files, not stored in the ICB: nothing special here. Just call blockdev_direct_IO() from our new udf_direct_IO() handler and tidy up any blocks instantiated outside i_size on error. This is pretty standard. Factor error handling code out of udf_write_begin() into new function udf_write_failed() so it can also be called by udf_direct_IO(). Also change the whitespace in udf_aops to make it a bit neater. Signed-off-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Jan Kara <jack@suse.cz>

UDF: Add support for O_DIRECT
Add support for the O_DIRECT flag. There are two cases to deal with: 1. Small files stored in the ICB (inode control block?): just return 0 from the new udf_adinicb_direct_IO() handler to fall back to buffered I/O. 2. Larger files, not stored in the ICB: nothing special here. Just call blockdev_direct_IO() from our new udf_direct_IO() handler and tidy up any blocks instantiated outside i_size on error. This is pretty standard. Factor error handling code out of udf_write_begin() into new function udf_write_failed() so it can also be called by udf_direct_IO(). Also change the whitespace in udf_aops to make it a bit neater. Signed-off-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Jan Kara <jack@suse.cz>
Ian Abbott · Jan Kara
1 parent 3f6bba8237
Showing 3 changed files with 46 additions and 17 deletions Side-by-side Diff
arch/um/os-Linux/time.c
fs/udf/file.c
fs/udf/inode.c
@@ -114,7 +114,7 @@
 	skew += this_tick - last_tick;
  
 	while (skew >= one_tick) {
-		alarm_handler(SIGVTALRM, NULL);
+		alarm_handler(SIGVTALRM, NULL, NULL);
 		skew -= one_tick;
 	}
  
@@ -118,11 +118,20 @@
 	return simple_write_end(file, mapping, pos, len, copied, page, fsdata);
 }
  
+static ssize_t udf_adinicb_direct_IO(int rw, struct kiocb *iocb,
+				     const struct iovec *iov,
+				     loff_t offset, unsigned long nr_segs)
+{
+	/* Fallback to buffered I/O. */
+	return 0;
+}
+
 const struct address_space_operations udf_adinicb_aops = {
 	.readpage	= udf_adinicb_readpage,
 	.writepage	= udf_adinicb_writepage,
 	.write_begin	= udf_adinicb_write_begin,
 	.write_end	= udf_adinicb_write_end,
+	.direct_IO	= udf_adinicb_direct_IO,
 };
  
 static ssize_t udf_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
@@ -95,6 +95,22 @@
 	}
 }
  
+static void udf_write_failed(struct address_space *mapping, loff_t to)
+{
+	struct inode *inode = mapping->host;
+	struct udf_inode_info *iinfo = UDF_I(inode);
+	loff_t isize = inode->i_size;
+
+	if (to > isize) {
+		truncate_pagecache(inode, to, isize);
+		if (iinfo->i_alloc_type != ICBTAG_FLAG_AD_IN_ICB) {
+			down_write(&iinfo->i_data_sem);
+			udf_truncate_extents(inode);
+			up_write(&iinfo->i_data_sem);
+		}
+	}
+}
+
 static int udf_writepage(struct page *page, struct writeback_control *wbc)
 {
 	return block_write_full_page(page, udf_get_block, wbc);
  
  
@@ -124,21 +140,24 @@
 	int ret;
  
 	ret = block_write_begin(mapping, pos, len, flags, pagep, udf_get_block);
-	if (unlikely(ret)) {
-		struct inode *inode = mapping->host;
-		struct udf_inode_info *iinfo = UDF_I(inode);
-		loff_t isize = inode->i_size;
+	if (unlikely(ret))
+		udf_write_failed(mapping, pos + len);
+	return ret;
+}
  
-		if (pos + len > isize) {
-			truncate_pagecache(inode, pos + len, isize);
-			if (iinfo->i_alloc_type != ICBTAG_FLAG_AD_IN_ICB) {
-				down_write(&iinfo->i_data_sem);
-				udf_truncate_extents(inode);
-				up_write(&iinfo->i_data_sem);
-			}
-		}
-	}
+static ssize_t udf_direct_IO(int rw, struct kiocb *iocb,
+			     const struct iovec *iov,
+			     loff_t offset, unsigned long nr_segs)
+{
+	struct file *file = iocb->ki_filp;
+	struct address_space *mapping = file->f_mapping;
+	struct inode *inode = mapping->host;
+	ssize_t ret;
  
+	ret = blockdev_direct_IO(rw, iocb, inode, iov, offset, nr_segs,
+				  udf_get_block);
+	if (unlikely(ret < 0 && (rw & WRITE)))
+		udf_write_failed(mapping, offset + iov_length(iov, nr_segs));
 	return ret;
 }
  
@@ -152,8 +171,9 @@
 	.readpages	= udf_readpages,
 	.writepage	= udf_writepage,
 	.writepages	= udf_writepages,
-	.write_begin		= udf_write_begin,
-	.write_end		= generic_write_end,
+	.write_begin	= udf_write_begin,
+	.write_end	= generic_write_end,
+	.direct_IO	= udf_direct_IO,
 	.bmap		= udf_bmap,
 };
...	...	@@ -114,7 +114,7 @@
114	114	skew += this_tick - last_tick;
115	115
116	116	while (skew >= one_tick) {
117		- alarm_handler(SIGVTALRM, NULL);
	117	+ alarm_handler(SIGVTALRM, NULL, NULL);
118	118	skew -= one_tick;
119	119	}
120	120
...	...	@@ -118,11 +118,20 @@
118	118	return simple_write_end(file, mapping, pos, len, copied, page, fsdata);
119	119	}
120	120
	121	+static ssize_t udf_adinicb_direct_IO(int rw, struct kiocb *iocb,
	122	+ const struct iovec *iov,
	123	+ loff_t offset, unsigned long nr_segs)
	124	+{
	125	+ /* Fallback to buffered I/O. */
	126	+ return 0;
	127	+}
	128	+
121	129	const struct address_space_operations udf_adinicb_aops = {
122	130	.readpage = udf_adinicb_readpage,
123	131	.writepage = udf_adinicb_writepage,
124	132	.write_begin = udf_adinicb_write_begin,
125	133	.write_end = udf_adinicb_write_end,
	134	+ .direct_IO = udf_adinicb_direct_IO,
126	135	};
127	136
128	137	static ssize_t udf_file_aio_write(struct kiocb iocb, const struct iovec iov,
...	...	@@ -95,6 +95,22 @@
95	95	}
96	96	}
97	97
	98	+static void udf_write_failed(struct address_space *mapping, loff_t to)
	99	+{
	100	+ struct inode *inode = mapping->host;
	101	+ struct udf_inode_info *iinfo = UDF_I(inode);
	102	+ loff_t isize = inode->i_size;
	103	+
	104	+ if (to > isize) {
	105	+ truncate_pagecache(inode, to, isize);
	106	+ if (iinfo->i_alloc_type != ICBTAG_FLAG_AD_IN_ICB) {
	107	+ down_write(&iinfo->i_data_sem);
	108	+ udf_truncate_extents(inode);
	109	+ up_write(&iinfo->i_data_sem);
	110	+ }
	111	+ }
	112	+}
	113	+
98	114	static int udf_writepage(struct page page, struct writeback_control wbc)
99	115	{
100	116	return block_write_full_page(page, udf_get_block, wbc);
101	117
102	118
...	...	@@ -124,21 +140,24 @@
124	140	int ret;
125	141
126	142	ret = block_write_begin(mapping, pos, len, flags, pagep, udf_get_block);
127		- if (unlikely(ret)) {
128		- struct inode *inode = mapping->host;
129		- struct udf_inode_info *iinfo = UDF_I(inode);
130		- loff_t isize = inode->i_size;
	143	+ if (unlikely(ret))
	144	+ udf_write_failed(mapping, pos + len);
	145	+ return ret;
	146	+}
131	147
132		- if (pos + len > isize) {
133		- truncate_pagecache(inode, pos + len, isize);
134		- if (iinfo->i_alloc_type != ICBTAG_FLAG_AD_IN_ICB) {
135		- down_write(&iinfo->i_data_sem);
136		- udf_truncate_extents(inode);
137		- up_write(&iinfo->i_data_sem);
138		- }
139		- }
140		- }
	148	+static ssize_t udf_direct_IO(int rw, struct kiocb *iocb,
	149	+ const struct iovec *iov,
	150	+ loff_t offset, unsigned long nr_segs)
	151	+{
	152	+ struct file *file = iocb->ki_filp;
	153	+ struct address_space *mapping = file->f_mapping;
	154	+ struct inode *inode = mapping->host;
	155	+ ssize_t ret;
141	156
	157	+ ret = blockdev_direct_IO(rw, iocb, inode, iov, offset, nr_segs,
	158	+ udf_get_block);
	159	+ if (unlikely(ret < 0 && (rw & WRITE)))
	160	+ udf_write_failed(mapping, offset + iov_length(iov, nr_segs));
142	161	return ret;
143	162	}
144	163
...	...	@@ -152,8 +171,9 @@
152	171	.readpages = udf_readpages,
153	172	.writepage = udf_writepage,
154	173	.writepages = udf_writepages,
155		- .write_begin = udf_write_begin,
156		- .write_end = generic_write_end,
	174	+ .write_begin = udf_write_begin,
	175	+ .write_end = generic_write_end,
	176	+ .direct_IO = udf_direct_IO,
157	177	.bmap = udf_bmap,
158	178	};
159	179