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- /*
- * 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();
- }
- asmlinkage long sys_sync(void)
- {
- 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_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;
- }
- asmlinkage long sys_fsync(unsigned int fd)
- {
- return __do_fsync(fd, 0);
- }
- asmlinkage long sys_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.
- *
- * 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.
- */
- asmlinkage long sys_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_file_range(file, offset, endbyte, flags);
- out_put:
- fput_light(file, fput_needed);
- out:
- return ret;
- }
- /*
- * `endbyte' is inclusive
- */
- int do_sync_file_range(struct file *file, loff_t offset, loff_t endbyte,
- unsigned int flags)
- {
- int ret;
- struct address_space *mapping;
- mapping = file->f_mapping;
- 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_NONE);
- 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_file_range);
|