rename the generic fsync implementations

We don't name our generic fsync implementations very well currently.
The no-op implementation for in-memory filesystems currently is called
simple_sync_file which doesn't make too much sense to start with,
the the generic one for simple filesystems is called simple_fsync
which can lead to some confusion.

This patch renames the generic file fsync method to generic_file_fsync
to match the other generic_file_* routines it is supposed to be used
with, and the no-op implementation to noop_fsync to make it obvious
what to expect.  In addition add some documentation for both methods.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

23 files changed, 44 insertions, 32 deletions

diff --git a/arch/powerpc/platforms/cell/spufs/inode.c b/arch/powerpc/platforms/cell/spufs/inode.c
index fc1b1c42b1dc..e5e5f823d687 100644
--- a/arch/powerpc/platforms/cell/spufs/inode.c
+++ b/arch/powerpc/platforms/cell/spufs/inode.c
@@ -251,7 +251,7 @@ const struct file_operations spufs_context_fops = {
         .llseek         = dcache_dir_lseek,
         .read           = generic_read_dir,
         .readdir        = dcache_readdir,
-        .fsync          = simple_sync_file,
+        .fsync          = noop_fsync,
 };
 EXPORT_SYMBOL_GPL(spufs_context_fops);
 
diff --git a/fs/adfs/dir.c b/fs/adfs/dir.c
index 23aa52f548a0..f4287e4de744 100644
--- a/fs/adfs/dir.c
+++ b/fs/adfs/dir.c
@@ -197,7 +197,7 @@ const struct file_operations adfs_dir_operations = {
         .read           = generic_read_dir,
         .llseek         = generic_file_llseek,
         .readdir        = adfs_readdir,
-        .fsync          = simple_fsync,
+        .fsync          = generic_file_fsync,
 };
 
 static int
diff --git a/fs/adfs/file.c b/fs/adfs/file.c
index 005ea34d1758..a36da5382b40 100644
--- a/fs/adfs/file.c
+++ b/fs/adfs/file.c
@@ -26,7 +26,7 @@ const struct file_operations adfs_file_operations = {
         .read           = do_sync_read,
         .aio_read       = generic_file_aio_read,
         .mmap           = generic_file_mmap,
-        .fsync          = simple_fsync,
+        .fsync          = generic_file_fsync,
         .write          = do_sync_write,
         .aio_write      = generic_file_aio_write,
         .splice_read    = generic_file_splice_read,
diff --git a/fs/bfs/dir.c b/fs/bfs/dir.c
index 8f73841fc974..d967e052b779 100644
--- a/fs/bfs/dir.c
+++ b/fs/bfs/dir.c
@@ -78,7 +78,7 @@ static int bfs_readdir(struct file *f, void *dirent, filldir_t filldir)
 const struct file_operations bfs_dir_operations = {
         .read           = generic_read_dir,
         .readdir        = bfs_readdir,
-        .fsync          = simple_fsync,
+        .fsync          = generic_file_fsync,
         .llseek         = generic_file_llseek,
 };
 
diff --git a/fs/ext2/file.c b/fs/ext2/file.c
index 48bcfc327014..d82e7ca93455 100644
--- a/fs/ext2/file.c
+++ b/fs/ext2/file.c
@@ -46,7 +46,7 @@ int ext2_fsync(struct file *file, int datasync)
         struct super_block *sb = file->f_mapping->host->i_sb;
         struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping;
 
-        ret = simple_fsync(file, datasync);
+        ret = generic_file_fsync(file, datasync);
         if (ret == -EIO || test_and_clear_bit(AS_EIO, &mapping->flags)) {
                 /* We don't really know where the IO error happened... */
                 ext2_error(sb, __func__,
diff --git a/fs/ext4/fsync.c b/fs/ext4/fsync.c
index 40f345201737..592adf2e546e 100644
--- a/fs/ext4/fsync.c
+++ b/fs/ext4/fsync.c
@@ -91,7 +91,7 @@ int ext4_sync_file(struct file *file, int datasync)
                 return ret;
 
         if (!journal) {
-                ret = simple_fsync(file, datasync);
+                ret = generic_file_fsync(file, datasync);
                 if (!ret && !list_empty(&inode->i_dentry))
                         ext4_sync_parent(inode);
                 return ret;
diff --git a/fs/fat/file.c b/fs/fat/file.c
index 29a576944374..8c13b8acfd2f 100644
--- a/fs/fat/file.c
+++ b/fs/fat/file.c
@@ -154,7 +154,7 @@ int fat_file_fsync(struct file *filp, int datasync)
         struct inode *inode = filp->f_mapping->host;
         int res, err;
 
-        res = simple_fsync(filp, datasync);
+        res = generic_file_fsync(filp, datasync);
         err = sync_mapping_buffers(MSDOS_SB(inode->i_sb)->fat_inode->i_mapping);
 
         return res ? res : err;
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index a0bbd3d1b41a..a4e9a7ec3691 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -688,7 +688,7 @@ static void init_once(void *foo)
 const struct file_operations hugetlbfs_file_operations = {
         .read                   = hugetlbfs_read,
         .mmap                   = hugetlbfs_file_mmap,
-        .fsync                  = simple_sync_file,
+        .fsync                  = noop_fsync,
         .get_unmapped_area      = hugetlb_get_unmapped_area,
 };
 
diff --git a/fs/libfs.c b/fs/libfs.c
index e57ea58bda68..b84d0a7a2204 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -58,11 +58,6 @@ struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, struct na
         return NULL;
 }
 
-int simple_sync_file(struct file *file, int datasync)
-{
-        return 0;
-}
- 
 int dcache_dir_open(struct inode *inode, struct file *file)
 {
         static struct qstr cursor_name = {.len = 1, .name = "."};
@@ -190,7 +185,7 @@ const struct file_operations simple_dir_operations = {
         .llseek         = dcache_dir_lseek,
         .read           = generic_read_dir,
         .readdir        = dcache_readdir,
-        .fsync          = simple_sync_file,
+        .fsync          = noop_fsync,
 };
 
 const struct inode_operations simple_dir_inode_operations = {
@@ -851,7 +846,16 @@ struct dentry *generic_fh_to_parent(struct super_block *sb, struct fid *fid,
 }
 EXPORT_SYMBOL_GPL(generic_fh_to_parent);
 
-int simple_fsync(struct file *file, int datasync)
+/**
+ * generic_file_fsync - generic fsync implementation for simple filesystems
+ * @file:       file to synchronize
+ * @datasync:   only synchronize essential metadata if true
+ *
+ * This is a generic implementation of the fsync method for simple
+ * filesystems which track all non-inode metadata in the buffers list
+ * hanging off the address_space structure.
+ */
+int generic_file_fsync(struct file *file, int datasync)
 {
         struct writeback_control wbc = {
                 .sync_mode = WB_SYNC_ALL,
@@ -872,7 +876,15 @@ int simple_fsync(struct file *file, int datasync)
                 ret = err;
         return ret;
 }
-EXPORT_SYMBOL(simple_fsync);
+EXPORT_SYMBOL(generic_file_fsync);
+
+/*
+ * No-op implementation of ->fsync for in-memory filesystems.
+ */
+int noop_fsync(struct file *file, int datasync)
+{
+        return 0;
+}
 
 EXPORT_SYMBOL(dcache_dir_close);
 EXPORT_SYMBOL(dcache_dir_lseek);
@@ -895,7 +907,7 @@ EXPORT_SYMBOL(simple_release_fs);
 EXPORT_SYMBOL(simple_rename);
 EXPORT_SYMBOL(simple_rmdir);
 EXPORT_SYMBOL(simple_statfs);
-EXPORT_SYMBOL(simple_sync_file);
+EXPORT_SYMBOL(noop_fsync);
 EXPORT_SYMBOL(simple_unlink);
 EXPORT_SYMBOL(simple_read_from_buffer);
 EXPORT_SYMBOL(simple_write_to_buffer);
diff --git a/fs/minix/dir.c b/fs/minix/dir.c
index 6198731d7fcd..aaab97ec5bc0 100644
--- a/fs/minix/dir.c
+++ b/fs/minix/dir.c
@@ -22,7 +22,7 @@ const struct file_operations minix_dir_operations = {
         .llseek         = generic_file_llseek,
         .read           = generic_read_dir,
         .readdir        = minix_readdir,
-        .fsync          = simple_fsync,
+        .fsync          = generic_file_fsync,
 };
 
 static inline void dir_put_page(struct page *page)
diff --git a/fs/minix/file.c b/fs/minix/file.c
index 3eec3e607a87..d5320ff23faf 100644
--- a/fs/minix/file.c
+++ b/fs/minix/file.c
@@ -19,7 +19,7 @@ const struct file_operations minix_file_operations = {
         .write          = do_sync_write,
         .aio_write      = generic_file_aio_write,
         .mmap           = generic_file_mmap,
-        .fsync          = simple_fsync,
+        .fsync          = generic_file_fsync,
         .splice_read    = generic_file_splice_read,
 };
 
diff --git a/fs/omfs/file.c b/fs/omfs/file.c
index 399487c09364..6e7a3291bbe8 100644
--- a/fs/omfs/file.c
+++ b/fs/omfs/file.c
@@ -329,7 +329,7 @@ const struct file_operations omfs_file_operations = {
         .aio_read = generic_file_aio_read,
         .aio_write = generic_file_aio_write,
         .mmap = generic_file_mmap,
-        .fsync = simple_fsync,
+        .fsync = generic_file_fsync,
         .splice_read = generic_file_splice_read,
 };
 
diff --git a/fs/qnx4/dir.c b/fs/qnx4/dir.c
index 3d3fd4692133..6e8fc62b40a8 100644
--- a/fs/qnx4/dir.c
+++ b/fs/qnx4/dir.c
@@ -80,7 +80,7 @@ const struct file_operations qnx4_dir_operations =
         .llseek         = generic_file_llseek,
         .read           = generic_read_dir,
         .readdir        = qnx4_readdir,
-        .fsync          = simple_fsync,
+        .fsync          = generic_file_fsync,
 };
 
 const struct inode_operations qnx4_dir_inode_operations =
diff --git a/fs/ramfs/file-mmu.c b/fs/ramfs/file-mmu.c
index 78f613cb9c76..50020501c5eb 100644
--- a/fs/ramfs/file-mmu.c
+++ b/fs/ramfs/file-mmu.c
@@ -43,7 +43,7 @@ const struct file_operations ramfs_file_operations = {
         .write          = do_sync_write,
         .aio_write      = generic_file_aio_write,
         .mmap           = generic_file_mmap,
-        .fsync          = simple_sync_file,
+        .fsync          = noop_fsync,
         .splice_read    = generic_file_splice_read,
         .splice_write   = generic_file_splice_write,
         .llseek         = generic_file_llseek,
diff --git a/fs/ramfs/file-nommu.c b/fs/ramfs/file-nommu.c
index 5ea4ad81a429..869f2d80183d 100644
--- a/fs/ramfs/file-nommu.c
+++ b/fs/ramfs/file-nommu.c
@@ -42,7 +42,7 @@ const struct file_operations ramfs_file_operations = {
         .aio_read               = generic_file_aio_read,
         .write                  = do_sync_write,
         .aio_write              = generic_file_aio_write,
-        .fsync                  = simple_sync_file,
+        .fsync                  = noop_fsync,
         .splice_read            = generic_file_splice_read,
         .splice_write           = generic_file_splice_write,
         .llseek                 = generic_file_llseek,
diff --git a/fs/sysv/dir.c b/fs/sysv/dir.c
index 1dabed286b4c..79941e4964a4 100644
--- a/fs/sysv/dir.c
+++ b/fs/sysv/dir.c
@@ -24,7 +24,7 @@ const struct file_operations sysv_dir_operations = {
         .llseek         = generic_file_llseek,
         .read           = generic_read_dir,
         .readdir        = sysv_readdir,
-        .fsync          = simple_fsync,
+        .fsync          = generic_file_fsync,
 };
 
 static inline void dir_put_page(struct page *page)
diff --git a/fs/sysv/file.c b/fs/sysv/file.c
index 96340c01f4a7..750cc22349bd 100644
--- a/fs/sysv/file.c
+++ b/fs/sysv/file.c
@@ -26,7 +26,7 @@ const struct file_operations sysv_file_operations = {
         .write          = do_sync_write,
         .aio_write      = generic_file_aio_write,
         .mmap           = generic_file_mmap,
-        .fsync          = simple_fsync,
+        .fsync          = generic_file_fsync,
         .splice_read    = generic_file_splice_read,
 };
 
diff --git a/fs/udf/dir.c b/fs/udf/dir.c
index 1660c81ffa3d..51552bf50225 100644
--- a/fs/udf/dir.c
+++ b/fs/udf/dir.c
@@ -211,5 +211,5 @@ const struct file_operations udf_dir_operations = {
         .read                   = generic_read_dir,
         .readdir                = udf_readdir,
         .unlocked_ioctl         = udf_ioctl,
-        .fsync                  = simple_fsync,
+        .fsync                  = generic_file_fsync,
 };
diff --git a/fs/udf/file.c b/fs/udf/file.c
index baae3a723946..0660280aa180 100644
--- a/fs/udf/file.c
+++ b/fs/udf/file.c
@@ -224,7 +224,7 @@ const struct file_operations udf_file_operations = {
         .write                  = do_sync_write,
         .aio_write              = udf_file_aio_write,
         .release                = udf_release_file,
-        .fsync                  = simple_fsync,
+        .fsync                  = generic_file_fsync,
         .splice_read            = generic_file_splice_read,
         .llseek                 = generic_file_llseek,
 };
diff --git a/fs/ufs/dir.c b/fs/ufs/dir.c
index 317a0d444f6b..ec784756dc65 100644
--- a/fs/ufs/dir.c
+++ b/fs/ufs/dir.c
@@ -666,6 +666,6 @@ not_empty:
 const struct file_operations ufs_dir_operations = {
         .read           = generic_read_dir,
         .readdir        = ufs_readdir,
-        .fsync          = simple_fsync,
+        .fsync          = generic_file_fsync,
         .llseek         = generic_file_llseek,
 };
diff --git a/fs/ufs/file.c b/fs/ufs/file.c
index a8962cecde5b..d4c30d1bef86 100644
--- a/fs/ufs/file.c
+++ b/fs/ufs/file.c
@@ -42,6 +42,6 @@ const struct file_operations ufs_file_operations = {
         .aio_write      = generic_file_aio_write,
         .mmap           = generic_file_mmap,
         .open           = dquot_file_open,
-        .fsync          = simple_fsync,
+        .fsync          = generic_file_fsync,
         .splice_read    = generic_file_splice_read,
 };
diff --git a/include/linux/fs.h b/include/linux/fs.h
index eb39e5eb77f5..acf6c52a50dd 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2348,7 +2348,7 @@ extern int simple_link(struct dentry *, struct inode *, struct dentry *);
 extern int simple_unlink(struct inode *, struct dentry *);
 extern int simple_rmdir(struct inode *, struct dentry *);
 extern int simple_rename(struct inode *, struct dentry *, struct inode *, struct dentry *);
-extern int simple_sync_file(struct file *, int);
+extern int noop_fsync(struct file *, int);
 extern int simple_empty(struct dentry *);
 extern int simple_readpage(struct file *file, struct page *page);
 extern int simple_write_begin(struct file *file, struct address_space *mapping,
@@ -2373,7 +2373,7 @@ extern ssize_t simple_read_from_buffer(void __user *to, size_t count,
 extern ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos,
                 const void __user *from, size_t count);
 
-extern int simple_fsync(struct file *, int);
+extern int generic_file_fsync(struct file *, int);
 
 #ifdef CONFIG_MIGRATION
 extern int buffer_migrate_page(struct address_space *,
diff --git a/mm/shmem.c b/mm/shmem.c
index 855eaf5b8d5b..4daf8cecf422 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2433,7 +2433,7 @@ static const struct file_operations shmem_file_operations = {
         .write          = do_sync_write,
         .aio_read       = shmem_file_aio_read,
         .aio_write      = generic_file_aio_write,
-        .fsync          = simple_sync_file,
+        .fsync          = noop_fsync,
         .splice_read    = generic_file_splice_read,
         .splice_write   = generic_file_splice_write,
 #endif