fallocate should be a file operation

Currently all filesystems except XFS implement fallocate asynchronously,
while XFS forced a commit.  Both of these are suboptimal - in case of O_SYNC
I/O we really want our allocation on disk, especially for the !KEEP_SIZE
case where we actually grow the file with user-visible zeroes.  On the
other hand always commiting the transaction is a bad idea for fast-path
uses of fallocate like for example in recent Samba versions.   Given
that block allocation is a data plane operation anyway change it from
an inode operation to a file operation so that we have the file structure
available that lets us check for O_SYNC.

This also includes moving the code around for a few of the filesystems,
and remove the already unnedded S_ISDIR checks given that we only wire
up fallocate for regular files.

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

1 files changed, 2 insertions, 2 deletions

diff --git a/fs/open.c b/fs/open.c
index 5b6ef7e2859e..e52389e1f05b 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -255,10 +255,10 @@ int do_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
         if (((offset + len) > inode->i_sb->s_maxbytes) || ((offset + len) < 0))
                 return -EFBIG;
 
-        if (!inode->i_op->fallocate)
+        if (!file->f_op->fallocate)
                 return -EOPNOTSUPP;
 
-        return inode->i_op->fallocate(inode, mode, offset, len);
+        return file->f_op->fallocate(file, mode, offset, len);
 }
 
 SYSCALL_DEFINE(fallocate)(int fd, int mode, loff_t offset, loff_t len)