ext4: move check under lock scope to close a race.

[firefly-linux-kernel-4.4.55.git] / fs / xfs / xfs_iops.c

diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index d919ad7b16bf9acbe01c6531a9254b372426911a..e53a903314225c030c45f694b4ffdaa509fa1ce8 100644 (file)
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -751,6 +751,7 @@ xfs_setattr_size(
        int                     error;
        uint                    lock_flags = 0;
        uint                    commit_flags = 0;
+       bool                    did_zeroing = false;
 
        trace_xfs_setattr(ip);
 
@@ -794,20 +795,16 @@ xfs_setattr_size(
                return error;
 
        /*
-        * Now we can make the changes.  Before we join the inode to the
-        * transaction, take care of the part of the truncation that must be
-        * done without the inode lock.  This needs to be done before joining
-        * the inode to the transaction, because the inode cannot be unlocked
-        * once it is a part of the transaction.
+        * File data changes must be complete before we start the transaction to
+        * modify the inode.  This needs to be done before joining the inode to
+        * the transaction because the inode cannot be unlocked once it is a
+        * part of the transaction.
+        *
+        * Start with zeroing any data block beyond EOF that we may expose on
+        * file extension.
         */
        if (newsize > oldsize) {
-               /*
-                * Do the first part of growing a file: zero any data in the
-                * last block that is beyond the old EOF.  We need to do this
-                * before the inode is joined to the transaction to modify
-                * i_size.
-                */
-               error = xfs_zero_eof(ip, newsize, oldsize);
+               error = xfs_zero_eof(ip, newsize, oldsize, &did_zeroing);
                if (error)
                        return error;
        }
@@ -817,23 +814,18 @@ xfs_setattr_size(
         * any previous writes that are beyond the on disk EOF and the new
         * EOF that have not been written out need to be written here.  If we
         * do not write the data out, we expose ourselves to the null files
-        * problem.
-        *
-        * Only flush from the on disk size to the smaller of the in memory
-        * file size or the new size as that's the range we really care about
-        * here and prevents waiting for other data not within the range we
-        * care about here.
+        * problem. Note that this includes any block zeroing we did above;
+        * otherwise those blocks may not be zeroed after a crash.
         */
-       if (oldsize != ip->i_d.di_size && newsize > ip->i_d.di_size) {
+       if (newsize > ip->i_d.di_size &&
+           (oldsize != ip->i_d.di_size || did_zeroing)) {
                error = filemap_write_and_wait_range(VFS_I(ip)->i_mapping,
                                                      ip->i_d.di_size, newsize);
                if (error)
                        return error;
        }
 
-       /*
-        * Wait for all direct I/O to complete.
-        */
+       /* Now wait for all direct I/O to complete. */
        inode_dio_wait(inode);
 
        /*