linux/fs/sync.c
Jens Axboe a2a9537ac0 Get rid of pdflush_operation() in emergency sync and remount
Opencode a cheasy approach with kevent. The idea here is that we'll
add some generic delayed work infrastructure, which probably wont be
based on pdflush (or maybe it will, in which case we can just add it
back).

This is in preparation for getting rid of pdflush completely.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-03-26 11:01:36 +01:00

341 lines
8.6 KiB
C

/*
* 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;
}
static void do_sync_work(struct work_struct *work)
{
do_sync(0);
kfree(work);
}
void emergency_sync(void)
{
struct work_struct *work;
work = kmalloc(sizeof(*work), GFP_ATOMIC);
if (work) {
INIT_WORK(work, do_sync_work);
schedule_work(work);
}
}
/*
* 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;
}
/**
* vfs_fsync - perform a fsync or fdatasync on a file
* @file: file to sync
* @dentry: dentry of @file
* @data: only perform a fdatasync operation
*
* Write back data and metadata for @file to disk. If @datasync is
* set only metadata needed to access modified file data is written.
*
* In case this function is called from nfsd @file may be %NULL and
* only @dentry is set. This can only happen when the filesystem
* implements the export_operations API.
*/
int vfs_fsync(struct file *file, struct dentry *dentry, int datasync)
{
const struct file_operations *fop;
struct address_space *mapping;
int err, ret;
/*
* Get mapping and operations from the file in case we have
* as file, or get the default values for them in case we
* don't have a struct file available. Damn nfsd..
*/
if (file) {
mapping = file->f_mapping;
fop = file->f_op;
} else {
mapping = dentry->d_inode->i_mapping;
fop = dentry->d_inode->i_fop;
}
if (!fop || !fop->fsync) {
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 = fop->fsync(file, dentry, datasync);
if (!ret)
ret = err;
mutex_unlock(&mapping->host->i_mutex);
err = filemap_fdatawait(mapping);
if (!ret)
ret = err;
out:
return ret;
}
EXPORT_SYMBOL(vfs_fsync);
static int do_fsync(unsigned int fd, int datasync)
{
struct file *file;
int ret = -EBADF;
file = fget(fd);
if (file) {
ret = vfs_fsync(file, file->f_path.dentry, 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);