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[PATCH] xfs: implement fallocate V2

To: "Amit K. Arora" <aarora@xxxxxxxxxxxxxxxxxx>
Subject: [PATCH] xfs: implement fallocate V2
From: David Chinner <dgc@xxxxxxx>
Date: Mon, 16 Jul 2007 15:37:51 +1000
Cc: linux-fsdevel@xxxxxxxxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx, linux-ext4@xxxxxxxxxxxxxxx, xfs@xxxxxxxxxxx, tytso@xxxxxxx, cmm@xxxxxxxxxx, suparna@xxxxxxxxxx, adilger@xxxxxxxxxxxxx, dgc@xxxxxxx, michael.kerrisk@xxxxxxx
In-reply-to: <20070713184125.GA12156@xxxxxxxxxxxxxxxxxxxx>
References: <20070713184125.GA12156@xxxxxxxxxxxxxxxxxxxx>
Sender: xfs-bounce@xxxxxxxxxxx
User-agent: Mutt/1.4.2.1i
Initial implementation of ->fallocate for XFS.

Version 2:

o Make allocation and setting the file size atomic.
o Drop deallocate/punch functionality
o use mode field appropriately to determine if size needs changing.

---
 fs/xfs/linux-2.6/xfs_iops.c |   47 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)

Index: 2.6.x-xfs-new/fs/xfs/linux-2.6/xfs_iops.c
===================================================================
--- 2.6.x-xfs-new.orig/fs/xfs/linux-2.6/xfs_iops.c      2007-07-16 
14:16:02.090255611 +1000
+++ 2.6.x-xfs-new/fs/xfs/linux-2.6/xfs_iops.c   2007-07-16 14:50:07.087885337 
+1000
@@ -51,6 +51,7 @@
 #include <linux/xattr.h>
 #include <linux/namei.h>
 #include <linux/security.h>
+#include <linux/falloc.h>
 
 /*
  * Get a XFS inode from a given vnode.
@@ -812,6 +813,51 @@ xfs_vn_removexattr(
        return namesp->attr_remove(vp, attr, xflags);
 }
 
+/*
+ * generic space allocation vector.
+ *
+ * This should really through a bhv_vop before stuffing around
+ * with xfs_inodes and such.
+ */
+STATIC long
+xfs_vn_fallocate(
+       struct inode    *inode,
+       int             mode,
+       loff_t          offset,
+       loff_t          len)
+{
+       long            error = -EOPNOTSUPP;
+       bhv_vnode_t     *vp = vn_from_inode(inode);
+       bhv_desc_t      *bdp;
+       loff_t          new_size = 0;
+       xfs_flock64_t   bf;
+
+       bf.l_whence = 0;
+       bf.l_start = offset;
+       bf.l_len = len;
+
+       bdp = bhv_lookup_range(VN_BHV_HEAD(vp), VNODE_POSITION_XFS,
+                                               VNODE_POSITION_XFS);
+
+       xfs_ilock(xfs_vtoi(vp), XFS_IOLOCK_EXCL);
+       error = xfs_change_file_space(bdp, XFS_IOC_RESVSP, &bf, 0, NULL,
+                                                       ATTR_NOLOCK);
+       if (!error && !(mode & FALLOC_FL_KEEP_SIZE) &&
+           offset + len > i_size_read(inode))
+               new_size = offset + len;
+
+       /* Change file size if needed */
+       if (new_size) {
+               bhv_vattr_t     va;
+
+               va.va_mask = XFS_AT_SIZE;
+               va.va_size = new_size;
+               error = bhv_vop_setattr(vp, &va, ATTR_NOLOCK, NULL);
+       }
+
+       xfs_iunlock(xfs_vtoi(vp), XFS_IOLOCK_EXCL);
+       return error;
+}
 
 const struct inode_operations xfs_inode_operations = {
        .permission             = xfs_vn_permission,
@@ -822,6 +868,7 @@ const struct inode_operations xfs_inode_
        .getxattr               = xfs_vn_getxattr,
        .listxattr              = xfs_vn_listxattr,
        .removexattr            = xfs_vn_removexattr,
+       .fallocate              = xfs_vn_fallocate,
 };
 
 const struct inode_operations xfs_dir_inode_operations = {
-- 
Dave Chinner
Principal Engineer
SGI Australian Software Group


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