Initial import of modified Linux 2.6.28 tree

Original upstream URL:
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git | branch linux-2.6.28.y

1 files changed, 303 insertions, 0 deletions

diff --git a/fs/sync.c b/fs/sync.c
new file mode 100644
index 0000000..9e5f60d
--- /dev/null
+++ b/fs/sync.c
@@ -0,0 +1,303 @@
+/*
+ * High-level sync()-related operations
+ */
+
+#include <linux/kernel.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/writeback.h>
+#include <linux/syscalls.h>
+#include <linux/linkage.h>
+#include <linux/pagemap.h>
+#include <linux/quotaops.h>
+#include <linux/buffer_head.h>
+
+#define VALID_FLAGS (SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE| \
+			SYNC_FILE_RANGE_WAIT_AFTER)
+
+/*
+ * sync everything.  Start out by waking pdflush, because that writes back
+ * all queues in parallel.
+ */
+static void do_sync(unsigned long wait)
+{
+	wakeup_pdflush(0);
+	sync_inodes(0);		/* All mappings, inodes and their blockdevs */
+	DQUOT_SYNC(NULL);
+	sync_supers();		/* Write the superblocks */
+	sync_filesystems(0);	/* Start syncing the filesystems */
+	sync_filesystems(wait);	/* Waitingly sync the filesystems */
+	sync_inodes(wait);	/* Mappings, inodes and blockdevs, again. */
+	if (!wait)
+		printk("Emergency Sync complete\n");
+	if (unlikely(laptop_mode))
+		laptop_sync_completion();
+}
+
+SYSCALL_DEFINE0(sync)
+{
+	do_sync(1);
+	return 0;
+}
+
+void emergency_sync(void)
+{
+	pdflush_operation(do_sync, 0);
+}
+
+/*
+ * Generic function to fsync a file.
+ *
+ * filp may be NULL if called via the msync of a vma.
+ */
+int file_fsync(struct file *filp, struct dentry *dentry, int datasync)
+{
+	struct inode * inode = dentry->d_inode;
+	struct super_block * sb;
+	int ret, err;
+
+	/* sync the inode to buffers */
+	ret = write_inode_now(inode, 0);
+
+	/* sync the superblock to buffers */
+	sb = inode->i_sb;
+	lock_super(sb);
+	if (sb->s_dirt && sb->s_op->write_super)
+		sb->s_op->write_super(sb);
+	unlock_super(sb);
+
+	/* .. finally sync the buffers to disk */
+	err = sync_blockdev(sb->s_bdev);
+	if (!ret)
+		ret = err;
+	return ret;
+}
+
+long do_fsync(struct file *file, int datasync)
+{
+	int ret;
+	int err;
+	struct address_space *mapping = file->f_mapping;
+
+	if (!file->f_op || !file->f_op->fsync) {
+		/* Why?  We can still call filemap_fdatawrite */
+		ret = -EINVAL;
+		goto out;
+	}
+
+	ret = filemap_fdatawrite(mapping);
+
+	/*
+	 * We need to protect against concurrent writers, which could cause
+	 * livelocks in fsync_buffers_list().
+	 */
+	mutex_lock(&mapping->host->i_mutex);
+	err = file->f_op->fsync(file, file->f_path.dentry, datasync);
+	if (!ret)
+		ret = err;
+	mutex_unlock(&mapping->host->i_mutex);
+	err = filemap_fdatawait(mapping);
+	if (!ret)
+		ret = err;
+out:
+	return ret;
+}
+
+static long __do_fsync(unsigned int fd, int datasync)
+{
+	struct file *file;
+	int ret = -EBADF;
+
+	file = fget(fd);
+	if (file) {
+		ret = do_fsync(file, datasync);
+		fput(file);
+	}
+	return ret;
+}
+
+SYSCALL_DEFINE1(fsync, unsigned int, fd)
+{
+	return __do_fsync(fd, 0);
+}
+
+SYSCALL_DEFINE1(fdatasync, unsigned int, fd)
+{
+	return __do_fsync(fd, 1);
+}
+
+/*
+ * sys_sync_file_range() permits finely controlled syncing over a segment of
+ * a file in the range offset .. (offset+nbytes-1) inclusive.  If nbytes is
+ * zero then sys_sync_file_range() will operate from offset out to EOF.
+ *
+ * The flag bits are:
+ *
+ * SYNC_FILE_RANGE_WAIT_BEFORE: wait upon writeout of all pages in the range
+ * before performing the write.
+ *
+ * SYNC_FILE_RANGE_WRITE: initiate writeout of all those dirty pages in the
+ * range which are not presently under writeback. Note that this may block for
+ * significant periods due to exhaustion of disk request structures.
+ *
+ * SYNC_FILE_RANGE_WAIT_AFTER: wait upon writeout of all pages in the range
+ * after performing the write.
+ *
+ * Useful combinations of the flag bits are:
+ *
+ * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE: ensures that all pages
+ * in the range which were dirty on entry to sys_sync_file_range() are placed
+ * under writeout.  This is a start-write-for-data-integrity operation.
+ *
+ * SYNC_FILE_RANGE_WRITE: start writeout of all dirty pages in the range which
+ * are not presently under writeout.  This is an asynchronous flush-to-disk
+ * operation.  Not suitable for data integrity operations.
+ *
+ * SYNC_FILE_RANGE_WAIT_BEFORE (or SYNC_FILE_RANGE_WAIT_AFTER): wait for
+ * completion of writeout of all pages in the range.  This will be used after an
+ * earlier SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE operation to wait
+ * for that operation to complete and to return the result.
+ *
+ * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE|SYNC_FILE_RANGE_WAIT_AFTER:
+ * a traditional sync() operation.  This is a write-for-data-integrity operation
+ * which will ensure that all pages in the range which were dirty on entry to
+ * sys_sync_file_range() are committed to disk.
+ *
+ *
+ * SYNC_FILE_RANGE_WAIT_BEFORE and SYNC_FILE_RANGE_WAIT_AFTER will detect any
+ * I/O errors or ENOSPC conditions and will return those to the caller, after
+ * clearing the EIO and ENOSPC flags in the address_space.
+ *
+ * It should be noted that none of these operations write out the file's
+ * metadata.  So unless the application is strictly performing overwrites of
+ * already-instantiated disk blocks, there are no guarantees here that the data
+ * will be available after a crash.
+ */
+SYSCALL_DEFINE(sync_file_range)(int fd, loff_t offset, loff_t nbytes,
+				unsigned int flags)
+{
+	int ret;
+	struct file *file;
+	loff_t endbyte;			/* inclusive */
+	int fput_needed;
+	umode_t i_mode;
+
+	ret = -EINVAL;
+	if (flags & ~VALID_FLAGS)
+		goto out;
+
+	endbyte = offset + nbytes;
+
+	if ((s64)offset < 0)
+		goto out;
+	if ((s64)endbyte < 0)
+		goto out;
+	if (endbyte < offset)
+		goto out;
+
+	if (sizeof(pgoff_t) == 4) {
+		if (offset >= (0x100000000ULL << PAGE_CACHE_SHIFT)) {
+			/*
+			 * The range starts outside a 32 bit machine's
+			 * pagecache addressing capabilities.  Let it "succeed"
+			 */
+			ret = 0;
+			goto out;
+		}
+		if (endbyte >= (0x100000000ULL << PAGE_CACHE_SHIFT)) {
+			/*
+			 * Out to EOF
+			 */
+			nbytes = 0;
+		}
+	}
+
+	if (nbytes == 0)
+		endbyte = LLONG_MAX;
+	else
+		endbyte--;		/* inclusive */
+
+	ret = -EBADF;
+	file = fget_light(fd, &fput_needed);
+	if (!file)
+		goto out;
+
+	i_mode = file->f_path.dentry->d_inode->i_mode;
+	ret = -ESPIPE;
+	if (!S_ISREG(i_mode) && !S_ISBLK(i_mode) && !S_ISDIR(i_mode) &&
+			!S_ISLNK(i_mode))
+		goto out_put;
+
+	ret = do_sync_mapping_range(file->f_mapping, offset, endbyte, flags);
+out_put:
+	fput_light(file, fput_needed);
+out:
+	return ret;
+}
+#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
+asmlinkage long SyS_sync_file_range(long fd, loff_t offset, loff_t nbytes,
+				    long flags)
+{
+	return SYSC_sync_file_range((int) fd, offset, nbytes,
+				    (unsigned int) flags);
+}
+SYSCALL_ALIAS(sys_sync_file_range, SyS_sync_file_range);
+#endif
+
+/* It would be nice if people remember that not all the world's an i386
+   when they introduce new system calls */
+SYSCALL_DEFINE(sync_file_range2)(int fd, unsigned int flags,
+				 loff_t offset, loff_t nbytes)
+{
+	return sys_sync_file_range(fd, offset, nbytes, flags);
+}
+#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
+asmlinkage long SyS_sync_file_range2(long fd, long flags,
+				     loff_t offset, loff_t nbytes)
+{
+	return SYSC_sync_file_range2((int) fd, (unsigned int) flags,
+				     offset, nbytes);
+}
+SYSCALL_ALIAS(sys_sync_file_range2, SyS_sync_file_range2);
+#endif
+
+/*
+ * `endbyte' is inclusive
+ */
+int do_sync_mapping_range(struct address_space *mapping, loff_t offset,
+			  loff_t endbyte, unsigned int flags)
+{
+	int ret;
+
+	if (!mapping) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	ret = 0;
+	if (flags & SYNC_FILE_RANGE_WAIT_BEFORE) {
+		ret = wait_on_page_writeback_range(mapping,
+					offset >> PAGE_CACHE_SHIFT,
+					endbyte >> PAGE_CACHE_SHIFT);
+		if (ret < 0)
+			goto out;
+	}
+
+	if (flags & SYNC_FILE_RANGE_WRITE) {
+		ret = __filemap_fdatawrite_range(mapping, offset, endbyte,
+						WB_SYNC_ALL);
+		if (ret < 0)
+			goto out;
+	}
+
+	if (flags & SYNC_FILE_RANGE_WAIT_AFTER) {
+		ret = wait_on_page_writeback_range(mapping,
+					offset >> PAGE_CACHE_SHIFT,
+					endbyte >> PAGE_CACHE_SHIFT);
+	}
+out:
+	return ret;
+}
+EXPORT_SYMBOL_GPL(do_sync_mapping_range);