alistair23-linux/fs/xfs/xfs_icache.h
Brian Foster dc06f398f0 xfs: run an eofblocks scan on ENOSPC/EDQUOT
From: Brian Foster <bfoster@redhat.com>

Speculative preallocation and and the associated throttling metrics
assume we're working with large files on large filesystems. Users have
reported inefficiencies in these mechanisms when we happen to be dealing
with large files on smaller filesystems. This can occur because while
prealloc throttling is aggressive under low free space conditions, it is
not active until we reach 5% free space or less.

For example, a 40GB filesystem has enough space for several files large
enough to have multi-GB preallocations at any given time. If those files
are slow growing, they might reserve preallocation for long periods of
time as well as avoid the background scanner due to frequent
modification. If a new file is written under these conditions, said file
has no access to this already reserved space and premature ENOSPC is
imminent.

To handle this scenario, modify the buffered write ENOSPC handling and
retry sequence to invoke an eofblocks scan. In the smaller filesystem
scenario, the eofblocks scan resets the usage of preallocation such that
when the 5% free space threshold is met, throttling effectively takes
over to provide fair and efficient preallocation until legitimate
ENOSPC.

The eofblocks scan is selective based on the nature of the failure. For
example, an EDQUOT failure in a particular quota will use a filtered
scan for that quota. Because we don't know which quota might have caused
an allocation failure at any given time, we include each applicable
quota determined to be under low free space conditions in the scan.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-07-24 19:49:28 +10:00

108 lines
3.2 KiB
C

/*
* Copyright (c) 2000-2006 Silicon Graphics, Inc.
* All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it would be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef XFS_SYNC_H
#define XFS_SYNC_H 1
struct xfs_mount;
struct xfs_perag;
struct xfs_eofblocks {
__u32 eof_flags;
kuid_t eof_uid;
kgid_t eof_gid;
prid_t eof_prid;
__u64 eof_min_file_size;
xfs_ino_t eof_scan_owner;
};
#define SYNC_WAIT 0x0001 /* wait for i/o to complete */
#define SYNC_TRYLOCK 0x0002 /* only try to lock inodes */
/*
* Flags for xfs_iget()
*/
#define XFS_IGET_CREATE 0x1
#define XFS_IGET_UNTRUSTED 0x2
#define XFS_IGET_DONTCACHE 0x4
int xfs_iget(struct xfs_mount *mp, struct xfs_trans *tp, xfs_ino_t ino,
uint flags, uint lock_flags, xfs_inode_t **ipp);
/* recovery needs direct inode allocation capability */
struct xfs_inode * xfs_inode_alloc(struct xfs_mount *mp, xfs_ino_t ino);
void xfs_inode_free(struct xfs_inode *ip);
void xfs_reclaim_worker(struct work_struct *work);
int xfs_reclaim_inodes(struct xfs_mount *mp, int mode);
int xfs_reclaim_inodes_count(struct xfs_mount *mp);
long xfs_reclaim_inodes_nr(struct xfs_mount *mp, int nr_to_scan);
void xfs_inode_set_reclaim_tag(struct xfs_inode *ip);
void xfs_inode_set_eofblocks_tag(struct xfs_inode *ip);
void xfs_inode_clear_eofblocks_tag(struct xfs_inode *ip);
int xfs_icache_free_eofblocks(struct xfs_mount *, struct xfs_eofblocks *);
int xfs_inode_free_quota_eofblocks(struct xfs_inode *ip);
void xfs_eofblocks_worker(struct work_struct *);
int xfs_inode_ag_iterator(struct xfs_mount *mp,
int (*execute)(struct xfs_inode *ip, int flags, void *args),
int flags, void *args);
int xfs_inode_ag_iterator_tag(struct xfs_mount *mp,
int (*execute)(struct xfs_inode *ip, int flags, void *args),
int flags, void *args, int tag);
static inline int
xfs_fs_eofblocks_from_user(
struct xfs_fs_eofblocks *src,
struct xfs_eofblocks *dst)
{
if (src->eof_version != XFS_EOFBLOCKS_VERSION)
return -EINVAL;
if (src->eof_flags & ~XFS_EOF_FLAGS_VALID)
return -EINVAL;
if (memchr_inv(&src->pad32, 0, sizeof(src->pad32)) ||
memchr_inv(src->pad64, 0, sizeof(src->pad64)))
return -EINVAL;
dst->eof_flags = src->eof_flags;
dst->eof_prid = src->eof_prid;
dst->eof_min_file_size = src->eof_min_file_size;
dst->eof_scan_owner = NULLFSINO;
dst->eof_uid = INVALID_UID;
if (src->eof_flags & XFS_EOF_FLAGS_UID) {
dst->eof_uid = make_kuid(current_user_ns(), src->eof_uid);
if (!uid_valid(dst->eof_uid))
return -EINVAL;
}
dst->eof_gid = INVALID_GID;
if (src->eof_flags & XFS_EOF_FLAGS_GID) {
dst->eof_gid = make_kgid(current_user_ns(), src->eof_gid);
if (!gid_valid(dst->eof_gid))
return -EINVAL;
}
return 0;
}
#endif