mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-21 16:29:59 +00:00
c3155097ad
The xfs_eofblocks.eof_scan_owner field is an internal field to facilitate invoking eofb scans from the kernel while under the iolock. This is necessary because the eofb scan acquires the iolock of each inode. Synchronous scans are invoked on certain buffered write failures while under iolock. In such cases, the scan owner indicates that the context for the scan already owns the particular iolock and prevents a double lock deadlock. eofblocks scans while under iolock are still livelock prone in the event of multiple parallel scans, however. If multiple buffered writes to different inodes fail and invoke eofblocks scans at the same time, each scan avoids a deadlock with its own inode by virtue of the eof_scan_owner field, but will never be able to acquire the iolock of the inode from the parallel scan. Because the low free space scans are invoked with SYNC_WAIT, the scan will not return until it has processed every tagged inode and thus both scans will spin indefinitely on the iolock being held across the opposite scan. This problem can be reproduced reliably by generic/224 on systems with higher cpu counts (x16). To avoid this problem, simplify the semantics of eofblocks scans to never invoke a scan while under iolock. This means that the buffered write context must drop the iolock before the scan. It must reacquire the lock before the write retry and also repeat the initial write checks, as the original state might no longer be valid once the iolock was dropped. Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
121 lines
3.8 KiB
C
121 lines
3.8 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;
|
|
};
|
|
|
|
#define SYNC_WAIT 0x0001 /* wait for i/o to complete */
|
|
#define SYNC_TRYLOCK 0x0002 /* only try to lock inodes */
|
|
|
|
/*
|
|
* tags for inode radix tree
|
|
*/
|
|
#define XFS_ICI_NO_TAG (-1) /* special flag for an untagged lookup
|
|
in xfs_inode_ag_iterator */
|
|
#define XFS_ICI_RECLAIM_TAG 0 /* inode is to be reclaimed */
|
|
#define XFS_ICI_EOFBLOCKS_TAG 1 /* inode has blocks beyond EOF */
|
|
#define XFS_ICI_COWBLOCKS_TAG 2 /* inode can have cow blocks to gc */
|
|
|
|
/*
|
|
* 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 *);
|
|
void xfs_queue_eofblocks(struct xfs_mount *);
|
|
|
|
void xfs_inode_set_cowblocks_tag(struct xfs_inode *ip);
|
|
void xfs_inode_clear_cowblocks_tag(struct xfs_inode *ip);
|
|
int xfs_icache_free_cowblocks(struct xfs_mount *, struct xfs_eofblocks *);
|
|
int xfs_inode_free_quota_cowblocks(struct xfs_inode *ip);
|
|
void xfs_cowblocks_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_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
|