From 148f948ba877f4d3cdef036b1ff6d9f68986706a Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Mon, 17 Aug 2009 19:52:36 +0200 Subject: [PATCH] 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 CC: ocfs2-devel@oss.oracle.com CC: Joel Becker CC: Felix Blyakher CC: xfs@oss.sgi.com CC: Anton Altaparmakov CC: linux-ntfs-dev@lists.sourceforge.net CC: OGAWA Hirofumi CC: linux-ext4@vger.kernel.org CC: tytso@mit.edu Acked-by: Christoph Hellwig Signed-off-by: Jan Kara --- fs/splice.c | 22 +++++-------------- fs/sync.c | 55 ++++++++++++++++++++++++++++++++++++++++------ include/linux/fs.h | 3 +++ mm/filemap.c | 11 ++++------ 4 files changed, 61 insertions(+), 30 deletions(-) diff --git a/fs/splice.c b/fs/splice.c index 73766d24f97..819023733f8 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -976,25 +976,15 @@ generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out, if (ret > 0) { unsigned long nr_pages; + int err; - *ppos += ret; nr_pages = (ret + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; - /* - * If file or inode is SYNC and we actually wrote some data, - * sync it. - */ - if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) { - int err; - - mutex_lock(&inode->i_mutex); - err = generic_osync_inode(inode, mapping, - OSYNC_METADATA|OSYNC_DATA); - mutex_unlock(&inode->i_mutex); - - if (err) - ret = err; - } + err = generic_write_sync(out, *ppos, ret); + if (err) + ret = err; + else + *ppos += ret; balance_dirty_pages_ratelimited_nr(mapping, nr_pages); } diff --git a/fs/sync.c b/fs/sync.c index 103cc7fdd3d..4e15da01923 100644 --- a/fs/sync.c +++ b/fs/sync.c @@ -178,19 +178,23 @@ int file_fsync(struct file *filp, struct dentry *dentry, int datasync) } /** - * vfs_fsync - perform a fsync or fdatasync on a file + * vfs_fsync_range - helper to sync a range of data & metadata to disk * @file: file to sync * @dentry: dentry of @file - * @data: only perform a fdatasync operation + * @start: offset in bytes of the beginning of data range to sync + * @end: offset in bytes of the end of data range (inclusive) + * @datasync: perform only datasync * - * Write back data and metadata for @file to disk. If @datasync is - * set only metadata needed to access modified file data is written. + * Write back data in range @start..@end 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) +int vfs_fsync_range(struct file *file, struct dentry *dentry, loff_t start, + loff_t end, int datasync) { const struct file_operations *fop; struct address_space *mapping; @@ -214,7 +218,7 @@ int vfs_fsync(struct file *file, struct dentry *dentry, int datasync) goto out; } - ret = filemap_fdatawrite(mapping); + ret = filemap_fdatawrite_range(mapping, start, end); /* * We need to protect against concurrent writers, which could cause @@ -225,12 +229,32 @@ int vfs_fsync(struct file *file, struct dentry *dentry, int datasync) if (!ret) ret = err; mutex_unlock(&mapping->host->i_mutex); - err = filemap_fdatawait(mapping); + + err = filemap_fdatawait_range(mapping, start, end); if (!ret) ret = err; out: return ret; } +EXPORT_SYMBOL(vfs_fsync_range); + +/** + * vfs_fsync - perform a fsync or fdatasync on a file + * @file: file to sync + * @dentry: dentry of @file + * @datasync: 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) +{ + return vfs_fsync_range(file, dentry, 0, LLONG_MAX, datasync); +} EXPORT_SYMBOL(vfs_fsync); static int do_fsync(unsigned int fd, int datasync) @@ -256,6 +280,23 @@ SYSCALL_DEFINE1(fdatasync, unsigned int, fd) return do_fsync(fd, 1); } +/** + * generic_write_sync - perform syncing after a write if file / inode is sync + * @file: file to which the write happened + * @pos: offset where the write started + * @count: length of the write + * + * This is just a simple wrapper about our general syncing function. + */ +int generic_write_sync(struct file *file, loff_t pos, loff_t count) +{ + if (!(file->f_flags & O_SYNC) && !IS_SYNC(file->f_mapping->host)) + return 0; + return vfs_fsync_range(file, file->f_path.dentry, pos, + pos + count - 1, 1); +} +EXPORT_SYMBOL(generic_write_sync); + /* * 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 diff --git a/include/linux/fs.h b/include/linux/fs.h index 6c1be3a4ede..e2c7f516766 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2098,7 +2098,10 @@ extern int __filemap_fdatawrite_range(struct address_space *mapping, extern int filemap_fdatawrite_range(struct address_space *mapping, loff_t start, loff_t end); +extern int vfs_fsync_range(struct file *file, struct dentry *dentry, + loff_t start, loff_t end, int datasync); extern int vfs_fsync(struct file *file, struct dentry *dentry, int datasync); +extern int generic_write_sync(struct file *file, loff_t pos, loff_t count); extern void sync_supers(void); extern void emergency_sync(void); extern void emergency_remount(void); diff --git a/mm/filemap.c b/mm/filemap.c index 3587554f45e..849293c4f41 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -39,11 +39,10 @@ /* * FIXME: remove all knowledge of the buffer layer from the core VM */ -#include /* for generic_osync_inode */ +#include /* for try_to_free_buffers */ #include - /* * Shared mappings implemented 30.11.1994. It's not fully working yet, * though. @@ -2477,8 +2476,7 @@ ssize_t generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov, unsigned long nr_segs, loff_t pos) { struct file *file = iocb->ki_filp; - struct address_space *mapping = file->f_mapping; - struct inode *inode = mapping->host; + struct inode *inode = file->f_mapping->host; ssize_t ret; BUG_ON(iocb->ki_pos != pos); @@ -2487,11 +2485,10 @@ ssize_t generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov, ret = __generic_file_aio_write(iocb, iov, nr_segs, &iocb->ki_pos); mutex_unlock(&inode->i_mutex); - if ((ret > 0 || ret == -EIOCBQUEUED) && - ((file->f_flags & O_SYNC) || IS_SYNC(inode))) { + if (ret > 0 || ret == -EIOCBQUEUED) { ssize_t err; - err = sync_page_range(inode, mapping, pos, ret); + err = generic_write_sync(file, pos, ret); if (err < 0 && ret > 0) ret = err; }