/*
* Set ourselves up to free CoW blocks from this file. If it's already clean
* then we can bail out quickly, but otherwise we must back off if the file
* is undergoing some kind of write.
*/
static bool
xfs_prep_free_cowblocks(
struct xfs_inode *ip)
{
/*
* Just clear the tag if we have an empty cow fork or none at all. It's
* possible the inode was fully unshared since it was originally tagged.
*/
if (!xfs_inode_has_cow_data(ip)) {
trace_xfs_inode_free_cowblocks_invalid(ip);
xfs_inode_clear_cowblocks_tag(ip);
return false;
}
/*
* If the mapping is dirty or under writeback we cannot touch the
* CoW fork. Leave it alone if we're in the midst of a directio.
*/
if ((VFS_I(ip)->i_state & I_DIRTY_PAGES) ||
mapping_tagged(VFS_I(ip)->i_mapping, PAGECACHE_TAG_DIRTY) ||
mapping_tagged(VFS_I(ip)->i_mapping, PAGECACHE_TAG_WRITEBACK) ||
atomic_read(&VFS_I(ip)->i_dio_count))
return false;
return true;
}
/*
* Automatic CoW Reservation Freeing
*
* These functions automatically garbage collect leftover CoW reservations
* that were made on behalf of a cowextsize hint when we start to run out
* of quota or when the reservations sit around for too long. If the file
* has dirty pages or is undergoing writeback, its CoW reservations will
* be retained.
*
* The actual garbage collection piggybacks off the same code that runs
* the speculative EOF preallocation garbage collector.
*/
STATIC int
xfs_inode_free_cowblocks(
struct xfs_inode *ip,
int flags,
void *args)
{
int ret;
struct xfs_eofblocks *eofb = args;
int match;
struct xfs_ifork *ifp = XFS_IFORK_PTR(ip, XFS_COW_FORK);
/*
* Just clear the tag if we have an empty cow fork or none at all. It's
* possible the inode was fully unshared since it was originally tagged.
*/
if (!xfs_is_reflink_inode(ip) || !ifp->if_bytes) {
trace_xfs_inode_free_cowblocks_invalid(ip);
xfs_inode_clear_cowblocks_tag(ip);
return 0;
}
/*
* If the mapping is dirty or under writeback we cannot touch the
* CoW fork. Leave it alone if we're in the midst of a directio.
*/
if ((VFS_I(ip)->i_state & I_DIRTY_PAGES) ||
mapping_tagged(VFS_I(ip)->i_mapping, PAGECACHE_TAG_DIRTY) ||
mapping_tagged(VFS_I(ip)->i_mapping, PAGECACHE_TAG_WRITEBACK) ||
atomic_read(&VFS_I(ip)->i_dio_count))
return 0;
if (eofb) {
if (eofb->eof_flags & XFS_EOF_FLAGS_UNION)
match = xfs_inode_match_id_union(ip, eofb);
else
match = xfs_inode_match_id(ip, eofb);
if (!match)
return 0;
/* skip the inode if the file size is too small */
if (eofb->eof_flags & XFS_EOF_FLAGS_MINFILESIZE &&
XFS_ISIZE(ip) < eofb->eof_min_file_size)
return 0;
}
/* Free the CoW blocks */
xfs_ilock(ip, XFS_IOLOCK_EXCL);
xfs_ilock(ip, XFS_MMAPLOCK_EXCL);
ret = xfs_reflink_cancel_cow_range(ip, 0, NULLFILEOFF, false);
xfs_iunlock(ip, XFS_MMAPLOCK_EXCL);
xfs_iunlock(ip, XFS_IOLOCK_EXCL);
return ret;
}
/*
* Automatic CoW Reservation Freeing
*
* These functions automatically garbage collect leftover CoW reservations
* that were made on behalf of a cowextsize hint when we start to run out
* of quota or when the reservations sit around for too long. If the file
* has dirty pages or is undergoing writeback, its CoW reservations will
* be retained.
*
* The actual garbage collection piggybacks off the same code that runs
* the speculative EOF preallocation garbage collector.
*/
STATIC int
xfs_inode_free_cowblocks(
struct xfs_inode *ip,
int flags,
void *args)
{
int ret;
struct xfs_eofblocks *eofb = args;
bool need_iolock = true;
int match;
ASSERT(!eofb || (eofb && eofb->eof_scan_owner != 0));
if (!xfs_reflink_has_real_cow_blocks(ip)) {
trace_xfs_inode_free_cowblocks_invalid(ip);
xfs_inode_clear_cowblocks_tag(ip);
return 0;
}
/*
* If the mapping is dirty or under writeback we cannot touch the
* CoW fork. Leave it alone if we're in the midst of a directio.
*/
if (mapping_tagged(VFS_I(ip)->i_mapping, PAGECACHE_TAG_DIRTY) ||
mapping_tagged(VFS_I(ip)->i_mapping, PAGECACHE_TAG_WRITEBACK) ||
atomic_read(&VFS_I(ip)->i_dio_count))
return 0;
if (eofb) {
if (eofb->eof_flags & XFS_EOF_FLAGS_UNION)
match = xfs_inode_match_id_union(ip, eofb);
else
match = xfs_inode_match_id(ip, eofb);
if (!match)
return 0;
/* skip the inode if the file size is too small */
if (eofb->eof_flags & XFS_EOF_FLAGS_MINFILESIZE &&
XFS_ISIZE(ip) < eofb->eof_min_file_size)
return 0;
/*
* A scan owner implies we already hold the iolock. Skip it in
* xfs_free_eofblocks() to avoid deadlock. This also eliminates
* the possibility of EAGAIN being returned.
*/
if (eofb->eof_scan_owner == ip->i_ino)
need_iolock = false;
}
/* Free the CoW blocks */
if (need_iolock) {
xfs_ilock(ip, XFS_IOLOCK_EXCL);
xfs_ilock(ip, XFS_MMAPLOCK_EXCL);
}
ret = xfs_reflink_cancel_cow_range(ip, 0, NULLFILEOFF);
if (need_iolock) {
xfs_iunlock(ip, XFS_MMAPLOCK_EXCL);
xfs_iunlock(ip, XFS_IOLOCK_EXCL);
}
return ret;
}
