d/freebsd-dev
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

MFV r271518:

Browse Source 
Correctly report hole at end of file.

When asked to find a hole, the DMU sees that there are no holes in the
object, and returns ESRCH.  The ZPL interprets this as "no holes before
the end of the file", and therefore inserts the "virtual hole" at the
end of the file.  Because DMU and ZPL have different ideas of where the
end of an object/file is, we will end up returning the end of file,
which is generally larger, instead of returning the end of object.

The fix is to handle the "virtual hole" in the DMU. If no hole is found,
the DMU will return a hole at the end of the file, rather than an error.

Illumos issue:
    5139 SEEK_HOLE failed to report a hole at end of file

MFC after:	1 week
This commit is contained in:
Xin LI 2014-09-13 17:48:44 +00:00
commit f9290bc2c9
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=271536
2 changed files with 22 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dnode.c
View File

@ -1948,6 +1948,15 @@ dnode_next_offset(dnode_t *dn, int flags, uint64_t *offset,
flags, offset, lvl, blkfill, txg);
}
/*
* There's always a "virtual hole" at the end of the object, even
* if all BP's which physically exist are non-holes.
*/
if ((flags & DNODE_FIND_HOLE) && error == ESRCH && txg == 0 &&
minlvl == 1 && blkfill == 1 && !(flags & DNODE_FIND_BACKWARDS)) {
error = 0;
}
if (error == 0 && (flags & DNODE_FIND_BACKWARDS ?
initial_offset < *offset : initial_offset > *offset))
error = SET_ERROR(ESRCH);

23
sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c
View File

@ -20,7 +20,7 @@
*/
/*
* Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2013, 2014 by Delphix. All rights reserved.
* Copyright (c) 2012, 2014 by Delphix. All rights reserved.
* Copyright 2014 Nexenta Systems, Inc. All rights reserved.
*/
@ -266,16 +266,19 @@ zfs_holey(vnode_t *vp, u_long cmd, offset_t *off)
error = dmu_offset_next(zp->z_zfsvfs->z_os, zp->z_id, hole, &noff);
/* end of file? */
if ((error == ESRCH) || (noff > file_sz)) {
/*
* Handle the virtual hole at the end of file.
*/
if (hole) {
*off = file_sz;
return (0);
}
if (error == ESRCH)
return (SET_ERROR(ENXIO));
/*
* We could find a hole that begins after the logical end-of-file,
* because dmu_offset_next() only works on whole blocks. If the
* EOF falls mid-block, then indicate that the "virtual hole"
* at the end of the file begins at the logical EOF, rather than
* at the end of the last block.
*/
if (noff > file_sz) {
ASSERT(hole);
noff = file_sz;
}
if (noff < *off)