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>

2 files changed, 56 insertions, 60 deletions

diff --git a/fs/xfs/linux-2.6/xfs_file.c b/fs/xfs/linux-2.6/xfs_file.c
index ef51eb43e137..a55c1b46b219 100644
--- a/fs/xfs/linux-2.6/xfs_file.c
+++ b/fs/xfs/linux-2.6/xfs_file.c
@@ -37,6 +37,7 @@
 #include "xfs_trace.h"
 
 #include <linux/dcache.h>
+#include <linux/falloc.h>
 
 static const struct vm_operations_struct xfs_file_vm_ops;
 
@@ -882,6 +883,60 @@ out_unlock:
         return ret;
 }
 
+STATIC long
+xfs_file_fallocate(
+        struct file     *file,
+        int             mode,
+        loff_t          offset,
+        loff_t          len)
+{
+        struct inode    *inode = file->f_path.dentry->d_inode;
+        long            error;
+        loff_t          new_size = 0;
+        xfs_flock64_t   bf;
+        xfs_inode_t     *ip = XFS_I(inode);
+        int             cmd = XFS_IOC_RESVSP;
+
+        if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
+                return -EOPNOTSUPP;
+
+        bf.l_whence = 0;
+        bf.l_start = offset;
+        bf.l_len = len;
+
+        xfs_ilock(ip, XFS_IOLOCK_EXCL);
+
+        if (mode & FALLOC_FL_PUNCH_HOLE)
+                cmd = XFS_IOC_UNRESVSP;
+
+        /* check the new inode size is valid before allocating */
+        if (!(mode & FALLOC_FL_KEEP_SIZE) &&
+            offset + len > i_size_read(inode)) {
+                new_size = offset + len;
+                error = inode_newsize_ok(inode, new_size);
+                if (error)
+                        goto out_unlock;
+        }
+
+        error = -xfs_change_file_space(ip, cmd, &bf, 0, XFS_ATTR_NOLOCK);
+        if (error)
+                goto out_unlock;
+
+        /* Change file size if needed */
+        if (new_size) {
+                struct iattr iattr;
+
+                iattr.ia_valid = ATTR_SIZE;
+                iattr.ia_size = new_size;
+                error = -xfs_setattr(ip, &iattr, XFS_ATTR_NOLOCK);
+        }
+
+out_unlock:
+        xfs_iunlock(ip, XFS_IOLOCK_EXCL);
+        return error;
+}
+
+
 STATIC int
 xfs_file_open(
         struct inode    *inode,
@@ -1000,6 +1055,7 @@ const struct file_operations xfs_file_operations = {
         .open           = xfs_file_open,
         .release        = xfs_file_release,
         .fsync          = xfs_file_fsync,
+        .fallocate      = xfs_file_fallocate,
 };
 
 const struct file_operations xfs_dir_file_operations = {
diff --git a/fs/xfs/linux-2.6/xfs_iops.c b/fs/xfs/linux-2.6/xfs_iops.c
index a4ecc2188a09..bd5727852fd6 100644
--- a/fs/xfs/linux-2.6/xfs_iops.c
+++ b/fs/xfs/linux-2.6/xfs_iops.c
@@ -46,7 +46,6 @@
 #include <linux/namei.h>
 #include <linux/posix_acl.h>
 #include <linux/security.h>
-#include <linux/falloc.h>
 #include <linux/fiemap.h>
 #include <linux/slab.h>
 
@@ -505,64 +504,6 @@ xfs_vn_setattr(
         return -xfs_setattr(XFS_I(dentry->d_inode), iattr, 0);
 }
 
-STATIC long
-xfs_vn_fallocate(
-        struct inode    *inode,
-        int             mode,
-        loff_t          offset,
-        loff_t          len)
-{
-        long            error;
-        loff_t          new_size = 0;
-        xfs_flock64_t   bf;
-        xfs_inode_t     *ip = XFS_I(inode);
-        int             cmd = XFS_IOC_RESVSP;
-
-        if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
-                return -EOPNOTSUPP;
-
-        /* preallocation on directories not yet supported */
-        error = -ENODEV;
-        if (S_ISDIR(inode->i_mode))
-                goto out_error;
-
-        bf.l_whence = 0;
-        bf.l_start = offset;
-        bf.l_len = len;
-
-        xfs_ilock(ip, XFS_IOLOCK_EXCL);
-
-        if (mode & FALLOC_FL_PUNCH_HOLE)
-                cmd = XFS_IOC_UNRESVSP;
-
-        /* check the new inode size is valid before allocating */
-        if (!(mode & FALLOC_FL_KEEP_SIZE) &&
-            offset + len > i_size_read(inode)) {
-                new_size = offset + len;
-                error = inode_newsize_ok(inode, new_size);
-                if (error)
-                        goto out_unlock;
-        }
-
-        error = -xfs_change_file_space(ip, cmd, &bf, 0, XFS_ATTR_NOLOCK);
-        if (error)
-                goto out_unlock;
-
-        /* Change file size if needed */
-        if (new_size) {
-                struct iattr iattr;
-
-                iattr.ia_valid = ATTR_SIZE;
-                iattr.ia_size = new_size;
-                error = -xfs_setattr(ip, &iattr, XFS_ATTR_NOLOCK);
-        }
-
-out_unlock:
-        xfs_iunlock(ip, XFS_IOLOCK_EXCL);
-out_error:
-        return error;
-}
-
 #define XFS_FIEMAP_FLAGS        (FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR)
 
 /*
@@ -656,7 +597,6 @@ static const struct inode_operations xfs_inode_operations = {
         .getxattr               = generic_getxattr,
         .removexattr            = generic_removexattr,
         .listxattr              = xfs_vn_listxattr,
-        .fallocate              = xfs_vn_fallocate,
         .fiemap                 = xfs_vn_fiemap,
 };