vfs: Introduce new helpers for syncing after writing to O_SYNC file or IS_SYNC inode
Introduce new function for generic inode syncing (vfs_fsync_range) and use it from fsync() path. Introduce also new helper for syncing after a sync write (generic_write_sync) using the generic function. Use these new helpers for syncing from generic VFS functions. This makes O_SYNC writes to block devices acquire i_mutex for syncing. If we really care about this, we can make block_fsync() drop the i_mutex and reacquire it before it returns. CC: Evgeniy Polyakov <zbr@ioremap.net> CC: ocfs2-devel@oss.oracle.com CC: Joel Becker <joel.becker@oracle.com> CC: Felix Blyakher <felixb@sgi.com> CC: xfs@oss.sgi.com CC: Anton Altaparmakov <aia21@cantab.net> CC: linux-ntfs-dev@lists.sourceforge.net CC: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> CC: linux-ext4@vger.kernel.org CC: tytso@mit.edu Acked-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz>
This commit is contained in:
Jan Kara
parent
eef9938067
commit
148f948ba8
4 changed files with 61 additions and 30 deletions
18
fs/splice.c
18
fs/splice.c
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@ -976,25 +976,15 @@ generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
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if (ret > 0) {
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unsigned long nr_pages;
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*ppos += ret;
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nr_pages = (ret + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
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/*
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* If file or inode is SYNC and we actually wrote some data,
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* sync it.
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*/
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if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) {
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int err;
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mutex_lock(&inode->i_mutex);
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err = generic_osync_inode(inode, mapping,
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OSYNC_METADATA|OSYNC_DATA);
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mutex_unlock(&inode->i_mutex);
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nr_pages = (ret + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
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err = generic_write_sync(out, *ppos, ret);
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if (err)
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ret = err;
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}
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else
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*ppos += ret;
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balance_dirty_pages_ratelimited_nr(mapping, nr_pages);
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}
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55
fs/sync.c
55
fs/sync.c
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@ -178,19 +178,23 @@ int file_fsync(struct file *filp, struct dentry *dentry, int datasync)
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}
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/**
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* vfs_fsync - perform a fsync or fdatasync on a file
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* vfs_fsync_range - helper to sync a range of data & metadata to disk
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* @file: file to sync
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* @dentry: dentry of @file
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* @data: only perform a fdatasync operation
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* @start: offset in bytes of the beginning of data range to sync
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* @end: offset in bytes of the end of data range (inclusive)
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* @datasync: perform only datasync
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*
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* Write back data and metadata for @file to disk. If @datasync is
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* set only metadata needed to access modified file data is written.
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* Write back data in range @start..@end and metadata for @file to disk. If
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* @datasync is set only metadata needed to access modified file data is
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* written.
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*
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* In case this function is called from nfsd @file may be %NULL and
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* only @dentry is set. This can only happen when the filesystem
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* implements the export_operations API.
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*/
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int vfs_fsync(struct file *file, struct dentry *dentry, int datasync)
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int vfs_fsync_range(struct file *file, struct dentry *dentry, loff_t start,
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loff_t end, int datasync)
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{
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const struct file_operations *fop;
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struct address_space *mapping;
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@ -214,7 +218,7 @@ int vfs_fsync(struct file *file, struct dentry *dentry, int datasync)
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goto out;
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}
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ret = filemap_fdatawrite(mapping);
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ret = filemap_fdatawrite_range(mapping, start, end);
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/*
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* We need to protect against concurrent writers, which could cause
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@ -225,12 +229,32 @@ int vfs_fsync(struct file *file, struct dentry *dentry, int datasync)
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if (!ret)
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ret = err;
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mutex_unlock(&mapping->host->i_mutex);
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err = filemap_fdatawait(mapping);
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err = filemap_fdatawait_range(mapping, start, end);
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if (!ret)
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ret = err;
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out:
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return ret;
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}
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EXPORT_SYMBOL(vfs_fsync_range);
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/**
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* vfs_fsync - perform a fsync or fdatasync on a file
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* @file: file to sync
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* @dentry: dentry of @file
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* @datasync: only perform a fdatasync operation
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*
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* Write back data and metadata for @file to disk. If @datasync is
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* set only metadata needed to access modified file data is written.
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*
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* In case this function is called from nfsd @file may be %NULL and
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* only @dentry is set. This can only happen when the filesystem
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* implements the export_operations API.
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*/
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int vfs_fsync(struct file *file, struct dentry *dentry, int datasync)
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{
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return vfs_fsync_range(file, dentry, 0, LLONG_MAX, datasync);
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}
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EXPORT_SYMBOL(vfs_fsync);
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static int do_fsync(unsigned int fd, int datasync)
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@ -256,6 +280,23 @@ SYSCALL_DEFINE1(fdatasync, unsigned int, fd)
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return do_fsync(fd, 1);
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}
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/**
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* generic_write_sync - perform syncing after a write if file / inode is sync
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* @file: file to which the write happened
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* @pos: offset where the write started
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* @count: length of the write
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*
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* This is just a simple wrapper about our general syncing function.
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*/
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int generic_write_sync(struct file *file, loff_t pos, loff_t count)
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{
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if (!(file->f_flags & O_SYNC) && !IS_SYNC(file->f_mapping->host))
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return 0;
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return vfs_fsync_range(file, file->f_path.dentry, pos,
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pos + count - 1, 1);
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}
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EXPORT_SYMBOL(generic_write_sync);
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/*
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* sys_sync_file_range() permits finely controlled syncing over a segment of
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* a file in the range offset .. (offset+nbytes-1) inclusive. If nbytes is
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@ -2098,7 +2098,10 @@ extern int __filemap_fdatawrite_range(struct address_space *mapping,
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extern int filemap_fdatawrite_range(struct address_space *mapping,
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loff_t start, loff_t end);
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extern int vfs_fsync_range(struct file *file, struct dentry *dentry,
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loff_t start, loff_t end, int datasync);
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extern int vfs_fsync(struct file *file, struct dentry *dentry, int datasync);
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extern int generic_write_sync(struct file *file, loff_t pos, loff_t count);
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extern void sync_supers(void);
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extern void emergency_sync(void);
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extern void emergency_remount(void);
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11
mm/filemap.c
11
mm/filemap.c
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@ -39,11 +39,10 @@
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/*
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* FIXME: remove all knowledge of the buffer layer from the core VM
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*/
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#include <linux/buffer_head.h> /* for generic_osync_inode */
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#include <linux/buffer_head.h> /* for try_to_free_buffers */
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#include <asm/mman.h>
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/*
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* Shared mappings implemented 30.11.1994. It's not fully working yet,
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* though.
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@ -2477,8 +2476,7 @@ ssize_t generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
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unsigned long nr_segs, loff_t pos)
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{
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struct file *file = iocb->ki_filp;
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struct address_space *mapping = file->f_mapping;
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struct inode *inode = mapping->host;
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struct inode *inode = file->f_mapping->host;
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ssize_t ret;
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BUG_ON(iocb->ki_pos != pos);
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@ -2487,11 +2485,10 @@ ssize_t generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
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ret = __generic_file_aio_write(iocb, iov, nr_segs, &iocb->ki_pos);
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mutex_unlock(&inode->i_mutex);
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if ((ret > 0 || ret == -EIOCBQUEUED) &&
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((file->f_flags & O_SYNC) || IS_SYNC(inode))) {
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if (ret > 0 || ret == -EIOCBQUEUED) {
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ssize_t err;
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err = sync_page_range(inode, mapping, pos, ret);
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err = generic_write_sync(file, pos, ret);
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if (err < 0 && ret > 0)
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ret = err;
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}
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