The UFS filesystem requires that the last block of a file always be
allocated. When shortening the length of a file in which the new end of the file contains a hole, the hole must have a block allocated. Reported by: Maxim Sobolev Reviewed by: kib Tested by: Peter Holm
This commit is contained in:
parent
3bead71e95
commit
24b6748c42
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=295950
@ -184,7 +184,7 @@ ffs_truncate(vp, length, flags, cred)
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struct inode *ip;
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ufs2_daddr_t bn, lbn, lastblock, lastiblock[NIADDR], indir_lbn[NIADDR];
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ufs2_daddr_t oldblks[NDADDR + NIADDR], newblks[NDADDR + NIADDR];
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ufs2_daddr_t count, blocksreleased = 0, datablocks;
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ufs2_daddr_t count, blocksreleased = 0, datablocks, blkno;
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struct bufobj *bo;
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struct fs *fs;
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struct buf *bp;
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@ -192,7 +192,7 @@ ffs_truncate(vp, length, flags, cred)
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int softdeptrunc, journaltrunc;
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int needextclean, extblocks;
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int offset, size, level, nblocks;
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int i, error, allerror;
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int i, error, allerror, indiroff;
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off_t osize;
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ip = VTOI(vp);
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@ -329,16 +329,57 @@ ffs_truncate(vp, length, flags, cred)
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ip->i_flag |= IN_CHANGE | IN_UPDATE;
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return (ffs_update(vp, !DOINGASYNC(vp)));
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}
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if (DOINGSOFTDEP(vp)) {
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/*
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* Lookup block number for a given offset. Zero length files
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* have no blocks, so return a blkno of -1.
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*/
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lbn = lblkno(fs, length - 1);
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if (length == 0) {
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blkno = -1;
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} else if (lbn < NDADDR) {
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blkno = DIP(ip, i_db[lbn]);
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} else {
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error = UFS_BALLOC(vp, lblktosize(fs, (off_t)lbn), fs->fs_bsize,
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cred, BA_METAONLY, &bp);
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if (error)
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return (error);
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indiroff = (lbn - NDADDR) % NINDIR(fs);
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if (ip->i_ump->um_fstype == UFS1)
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blkno = ((ufs1_daddr_t *)(bp->b_data))[indiroff];
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else
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blkno = ((ufs2_daddr_t *)(bp->b_data))[indiroff];
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/*
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* If the block number is non-zero, then the indirect block
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* must have been previously allocated and need not be written.
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* If the block number is zero, then we may have allocated
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* the indirect block and hence need to write it out.
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*/
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if (blkno != 0)
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brelse(bp);
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else if (DOINGSOFTDEP(vp) || DOINGASYNC(vp))
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bdwrite(bp);
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else
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bwrite(bp);
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}
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/*
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* If the block number at the new end of the file is zero,
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* then we must allocate it to ensure that the last block of
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* the file is allocated. Soft updates does not handle this
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* case, so here we have to clean up the soft updates data
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* structures describing the allocation past the truncation
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* point. Finding and deallocating those structures is a lot of
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* work. Since partial truncation with a hole at the end occurs
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* rarely, we solve the problem by syncing the file so that it
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* will have no soft updates data structures left.
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*/
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if (blkno == 0 && (error = ffs_syncvnode(vp, MNT_WAIT, 0)) != 0)
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return (error);
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if (blkno != 0 && DOINGSOFTDEP(vp)) {
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if (softdeptrunc == 0 && journaltrunc == 0) {
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/*
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* If a file is only partially truncated, then
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* we have to clean up the data structures
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* describing the allocation past the truncation
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* point. Finding and deallocating those structures
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* is a lot of work. Since partial truncation occurs
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* rarely, we solve the problem by syncing the file
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* so that it will have no data structures left.
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* If soft updates cannot handle this truncation,
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* clean up soft dependency data structures and
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* fall through to the synchronous truncation.
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*/
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if ((error = ffs_syncvnode(vp, MNT_WAIT, 0)) != 0)
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return (error);
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@ -358,15 +399,17 @@ ffs_truncate(vp, length, flags, cred)
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}
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}
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/*
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* Shorten the size of the file. If the file is not being
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* truncated to a block boundary, the contents of the
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* partial block following the end of the file must be
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* zero'ed in case it ever becomes accessible again because
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* of subsequent file growth. Directories however are not
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* Shorten the size of the file. If the last block of the
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* shortened file is unallocated, we must allocate it.
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* Additionally, if the file is not being truncated to a
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* block boundary, the contents of the partial block
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* following the end of the file must be zero'ed in
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* case it ever becomes accessible again because of
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* subsequent file growth. Directories however are not
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* zero'ed as they should grow back initialized to empty.
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*/
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offset = blkoff(fs, length);
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if (offset == 0) {
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if (blkno != 0 && offset == 0) {
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ip->i_size = length;
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DIP_SET(ip, i_size, length);
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} else {
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@ -390,7 +433,7 @@ ffs_truncate(vp, length, flags, cred)
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ip->i_size = length;
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DIP_SET(ip, i_size, length);
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size = blksize(fs, ip, lbn);
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if (vp->v_type != VDIR)
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if (vp->v_type != VDIR && offset != 0)
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bzero((char *)bp->b_data + offset,
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(u_int)(size - offset));
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/* Kirk's code has reallocbuf(bp, size, 1) here */
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