35338e6091
snapshots on UFS filesystems running with journaled soft updates. This is the first of several bugs that need to be fixed before removing the restriction added in -r230250 to prevent the use of snapshots on filesystems running with journaled soft updates. The deadlock occurs when holding the snapshot lock (snaplk) and then trying to flush an inode via ffs_update(). We become blocked by another process trying to flush a different inode contained in the same inode block that we need. It holds the inode block for which we are waiting locked. When it tries to write the inode block, it gets blocked waiting for the our snaplk when it calls ffs_copyonwrite() to see if the inode block needs to be copied in our snapshot. The most obvious place that this deadlock arises is in the ffs_copyonwrite() routine when it updates critical metadata in a snapshot and tries to write it out before proceeding. The fix here is to write the data and indirect block pointer for the snapshot, but to skip the call to ffs_update() to write the snapshot inode. To ensure that we will never have to update a pointer in the inode itself, the ffs_snapshot() routine that creates the snapshot has to ensure that all the direct blocks are allocated as part of the creation of the snapshot. A less obvious place that this deadlock occurs is when we hold the snaplk because we are deleting a snapshot. In the course of doing the deletion, we need to allocate various soft update dependency structures and allocate some journal space. If we hit a resource limit while doing this we decrease the resources in use by flushing out an existing dirty file to get it to give up the soft dependency resources that it holds. The flush can cause an ffs_update() to be done on the inode for the file that we have selected to flush resulting in the same deadlock as described above when the inode that we have chosen to flush resides in the same inode block as the snapshot inode that we hold. The fix is to defer cleaning up any time that the inode on which we are operating is a snapshot. Help and review by: Jeff Roberson Tested by: Peter Holm MFC (to 9 only) after: 2 weeks
193 lines
7.8 KiB
C
193 lines
7.8 KiB
C
/*-
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* Copyright (c) 1991, 1993, 1994
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)ffs_extern.h 8.6 (Berkeley) 3/30/95
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* $FreeBSD$
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*/
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#ifndef _UFS_FFS_EXTERN_H
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#define _UFS_FFS_EXTERN_H
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#ifndef _KERNEL
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#error "No user-serving parts inside"
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#else
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struct buf;
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struct cg;
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struct fid;
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struct fs;
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struct inode;
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struct malloc_type;
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struct mount;
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struct thread;
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struct sockaddr;
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struct statfs;
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struct ucred;
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struct vnode;
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struct vop_fsync_args;
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struct vop_reallocblks_args;
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struct workhead;
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int ffs_alloc(struct inode *, ufs2_daddr_t, ufs2_daddr_t, int, int,
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struct ucred *, ufs2_daddr_t *);
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int ffs_balloc_ufs1(struct vnode *a_vp, off_t a_startoffset, int a_size,
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struct ucred *a_cred, int a_flags, struct buf **a_bpp);
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int ffs_balloc_ufs2(struct vnode *a_vp, off_t a_startoffset, int a_size,
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struct ucred *a_cred, int a_flags, struct buf **a_bpp);
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int ffs_blkatoff(struct vnode *, off_t, char **, struct buf **);
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void ffs_blkfree(struct ufsmount *, struct fs *, struct vnode *,
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ufs2_daddr_t, long, ino_t, enum vtype, struct workhead *);
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ufs2_daddr_t ffs_blkpref_ufs1(struct inode *, ufs_lbn_t, int, ufs1_daddr_t *);
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ufs2_daddr_t ffs_blkpref_ufs2(struct inode *, ufs_lbn_t, int, ufs2_daddr_t *);
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int ffs_checkfreefile(struct fs *, struct vnode *, ino_t);
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void ffs_clrblock(struct fs *, u_char *, ufs1_daddr_t);
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void ffs_clusteracct(struct fs *, struct cg *, ufs1_daddr_t, int);
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void ffs_bdflush(struct bufobj *, struct buf *);
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int ffs_copyonwrite(struct vnode *, struct buf *);
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int ffs_flushfiles(struct mount *, int, struct thread *);
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void ffs_fragacct(struct fs *, int, int32_t [], int);
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int ffs_freefile(struct ufsmount *, struct fs *, struct vnode *, ino_t,
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int, struct workhead *);
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void ffs_fserr(struct fs *, ino_t, char *);
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int ffs_isblock(struct fs *, u_char *, ufs1_daddr_t);
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int ffs_isfreeblock(struct fs *, u_char *, ufs1_daddr_t);
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void ffs_load_inode(struct buf *, struct inode *, struct fs *, ino_t);
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int ffs_mountroot(void);
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void ffs_oldfscompat_write(struct fs *, struct ufsmount *);
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int ffs_reallocblks(struct vop_reallocblks_args *);
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int ffs_realloccg(struct inode *, ufs2_daddr_t, ufs2_daddr_t,
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ufs2_daddr_t, int, int, int, struct ucred *, struct buf **);
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int ffs_sbupdate(struct ufsmount *, int, int);
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void ffs_setblock(struct fs *, u_char *, ufs1_daddr_t);
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int ffs_snapblkfree(struct fs *, struct vnode *, ufs2_daddr_t, long, ino_t,
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enum vtype, struct workhead *);
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void ffs_snapremove(struct vnode *vp);
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int ffs_snapshot(struct mount *mp, char *snapfile);
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void ffs_snapshot_mount(struct mount *mp);
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void ffs_snapshot_unmount(struct mount *mp);
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void process_deferred_inactive(struct mount *mp);
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void ffs_sync_snap(struct mount *, int);
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int ffs_syncvnode(struct vnode *vp, int waitfor);
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int ffs_truncate(struct vnode *, off_t, int, struct ucred *, struct thread *);
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int ffs_update(struct vnode *, int);
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int ffs_valloc(struct vnode *, int, struct ucred *, struct vnode **);
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int ffs_vfree(struct vnode *, ino_t, int);
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vfs_vget_t ffs_vget;
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int ffs_vgetf(struct mount *, ino_t, int, struct vnode **, int);
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#define FFSV_FORCEINSMQ 0x0001
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extern struct vop_vector ffs_vnodeops1;
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extern struct vop_vector ffs_fifoops1;
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extern struct vop_vector ffs_vnodeops2;
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extern struct vop_vector ffs_fifoops2;
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/*
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* Soft update function prototypes.
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*/
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int softdep_check_suspend(struct mount *, struct vnode *,
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int, int, int, int);
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void softdep_get_depcounts(struct mount *, int *, int *);
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void softdep_initialize(void);
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void softdep_uninitialize(void);
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int softdep_mount(struct vnode *, struct mount *, struct fs *,
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struct ucred *);
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void softdep_unmount(struct mount *);
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int softdep_move_dependencies(struct buf *, struct buf *);
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int softdep_flushworklist(struct mount *, int *, struct thread *);
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int softdep_flushfiles(struct mount *, int, struct thread *);
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void softdep_update_inodeblock(struct inode *, struct buf *, int);
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void softdep_load_inodeblock(struct inode *);
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void softdep_freefile(struct vnode *, ino_t, int);
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int softdep_request_cleanup(struct fs *, struct vnode *,
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struct ucred *, int);
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void softdep_setup_freeblocks(struct inode *, off_t, int);
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void softdep_setup_inomapdep(struct buf *, struct inode *, ino_t, int);
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void softdep_setup_blkmapdep(struct buf *, struct mount *, ufs2_daddr_t,
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int, int);
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void softdep_setup_allocdirect(struct inode *, ufs_lbn_t, ufs2_daddr_t,
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ufs2_daddr_t, long, long, struct buf *);
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void softdep_setup_allocext(struct inode *, ufs_lbn_t, ufs2_daddr_t,
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ufs2_daddr_t, long, long, struct buf *);
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void softdep_setup_allocindir_meta(struct buf *, struct inode *,
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struct buf *, int, ufs2_daddr_t);
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void softdep_setup_allocindir_page(struct inode *, ufs_lbn_t,
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struct buf *, int, ufs2_daddr_t, ufs2_daddr_t, struct buf *);
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void softdep_setup_blkfree(struct mount *, struct buf *, ufs2_daddr_t, int,
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struct workhead *);
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void softdep_setup_inofree(struct mount *, struct buf *, ino_t,
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struct workhead *);
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void softdep_setup_sbupdate(struct ufsmount *, struct fs *, struct buf *);
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void softdep_fsync_mountdev(struct vnode *);
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int softdep_sync_metadata(struct vnode *);
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int softdep_sync_buf(struct vnode *, struct buf *, int);
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int softdep_process_worklist(struct mount *, int);
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int softdep_fsync(struct vnode *);
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int softdep_waitidle(struct mount *);
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int softdep_prealloc(struct vnode *, int);
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int softdep_journal_lookup(struct mount *, struct vnode **);
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void softdep_journal_freeblocks(struct inode *, struct ucred *, off_t, int);
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void softdep_journal_fsync(struct inode *);
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void softdep_buf_append(struct buf *, struct workhead *);
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void softdep_inode_append(struct inode *, struct ucred *, struct workhead *);
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void softdep_freework(struct workhead *);
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/*
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* Things to request flushing in softdep_request_cleanup()
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*/
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#define FLUSH_INODES 1
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#define FLUSH_INODES_WAIT 2
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#define FLUSH_BLOCKS 3
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#define FLUSH_BLOCKS_WAIT 4
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/*
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* Flag to ffs_syncinode() to request flushing of data only,
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* but skip the ffs_update() on the inode itself. Used to avoid
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* deadlock when flushing snapshot inodes while holding snaplk.
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* Avoid bit conflicts with MNT_WAIT values in sys/mount.h
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*/
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#define NO_INO_UPDT 0x10
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int ffs_rdonly(struct inode *);
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TAILQ_HEAD(snaphead, inode);
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struct snapdata {
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LIST_ENTRY(snapdata) sn_link;
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struct snaphead sn_head;
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daddr_t sn_listsize;
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daddr_t *sn_blklist;
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struct lock sn_lock;
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};
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#endif /* _KERNEL */
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#endif /* !_UFS_FFS_EXTERN_H */
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