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authorJan Kara <jack@suse.cz>2009-08-17 19:52:36 +0200
committerJan Kara <jack@suse.cz>2009-09-14 17:08:15 +0200
commit148f948ba877f4d3cdef036b1ff6d9f68986706a (patch)
treec07963f08bf8c2119ec00df64e4293e2e60acaa1 /fs/sync.c
parenteef99380679e20e7edc096aa4d8a98b875404d79 (diff)
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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>
Diffstat (limited to 'fs/sync.c')
-rw-r--r--fs/sync.c55
1 files changed, 48 insertions, 7 deletions
diff --git a/fs/sync.c b/fs/sync.c
index 103cc7fdd3df..4e15da01923c 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