- Permit zero length directories as a handled inconsistency. This allows
directory truncation to proceed before the link has been cleared. This is accomplished by detecting a directory with no . or .. links and clearing the named directory entry in the parent. - Add a new function ino_remref() which handles the details of removing a reference to an inode as a result of a lost directory. There were some minor errors in various subcases of this routine.
This commit is contained in:
Jeff Roberson
parent
48162ca1e0
commit
24d37c1eec
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=209716
@ -807,6 +807,44 @@ blk_isat(ino_t ino, ufs_lbn_t lbn, ufs2_daddr_t blk, int *frags)
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return (nblk == blk);
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}
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/*
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* Clear the directory entry at diroff that should point to child. Minimal
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* checking is done and it is assumed that this path was verified with isat.
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*/
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static void
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ino_clrat(ino_t parent, off_t diroff, ino_t child)
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{
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union dinode *dip;
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struct direct *dp;
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ufs2_daddr_t blk;
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uint8_t *block;
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ufs_lbn_t lbn;
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int blksize;
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int frags;
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int doff;
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if (debug)
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printf("Clearing inode %d from parent %d at offset %jd\n",
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child, parent, diroff);
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lbn = lblkno(fs, diroff);
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doff = blkoff(fs, diroff);
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dip = ino_read(parent);
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blk = ino_blkatoff(dip, parent, lbn, &frags);
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blksize = sblksize(fs, DIP(dip, di_size), lbn);
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block = dblk_read(blk, blksize);
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dp = (struct direct *)&block[doff];
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if (dp->d_ino != child)
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errx(1, "Inode %d does not exist in %d at %jd",
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child, parent, diroff);
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dp->d_ino = 0;
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dblk_dirty(blk);
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/*
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* The actual .. reference count will already have been removed
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* from the parent by the .. remref record.
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*/
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}
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/*
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* Determines whether a pointer to an inode exists within a directory
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* at a specified offset. Returns the mode of the found entry.
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@ -1134,6 +1172,57 @@ ino_setskip(struct suj_ino *sino, ino_t parent)
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sino->si_skipparent = 1;
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}
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static void
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ino_remref(ino_t parent, ino_t child, uint64_t diroff, int isdotdot)
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{
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struct suj_ino *sino;
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struct suj_rec *srec;
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struct jrefrec *rrec;
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/*
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* Lookup this inode to see if we have a record for it.
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*/
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sino = ino_lookup(child, 0);
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/*
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* Tell any child directories we've already removed their
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* parent link cnt. Don't try to adjust our link down again.
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*/
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if (sino != NULL && isdotdot == 0)
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ino_setskip(sino, parent);
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/*
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* No valid record for this inode. Just drop the on-disk
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* link by one.
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*/
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if (sino == NULL || sino->si_hasrecs == 0) {
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ino_decr(child);
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return;
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}
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/*
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* Use ino_adjust() if ino_check() has already processed this
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* child. If we lose the last non-dot reference to a
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* directory it will be discarded.
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*/
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if (sino->si_linkadj) {
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sino->si_nlink--;
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if (isdotdot)
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sino->si_dotlinks--;
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ino_adjust(sino);
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return;
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}
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/*
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* If we haven't yet processed this inode we need to make
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* sure we will successfully discover the lost path. If not
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* use nlinkadj to remember.
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*/
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TAILQ_FOREACH(srec, &sino->si_recs, sr_next) {
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rrec = (struct jrefrec *)srec->sr_rec;
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if (rrec->jr_parent == parent &&
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rrec->jr_diroff == diroff)
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return;
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}
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sino->si_nlinkadj++;
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}
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/*
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* Free the children of a directory when the directory is discarded.
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*/
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@ -1141,13 +1230,11 @@ static void
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ino_free_children(ino_t ino, ufs_lbn_t lbn, ufs2_daddr_t blk, int frags)
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{
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struct suj_ino *sino;
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struct suj_rec *srec;
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struct jrefrec *rrec;
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struct direct *dp;
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off_t diroff;
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uint8_t *block;
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int skipparent;
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int isparent;
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int isdotdot;
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int dpoff;
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int size;
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@ -1165,53 +1252,15 @@ ino_free_children(ino_t ino, ufs_lbn_t lbn, ufs2_daddr_t blk, int frags)
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continue;
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if (dp->d_namlen == 1 && dp->d_name[0] == '.')
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continue;
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isparent = dp->d_namlen == 2 && dp->d_name[0] == '.' &&
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isdotdot = dp->d_namlen == 2 && dp->d_name[0] == '.' &&
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dp->d_name[1] == '.';
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if (isparent && skipparent == 1)
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if (isdotdot && skipparent == 1)
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continue;
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if (debug)
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printf("Directory %d removing ino %d name %s\n",
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ino, dp->d_ino, dp->d_name);
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/*
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* Lookup this inode to see if we have a record for it.
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* If not, we've already adjusted it assuming this path
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* was valid and we have to adjust once more.
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*/
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sino = ino_lookup(dp->d_ino, 0);
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if (sino == NULL || sino->si_hasrecs == 0) {
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ino_decr(ino);
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continue;
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}
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/*
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* Use ino_adjust() so if we lose the last non-dot reference
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* to a directory it can be discarded.
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*/
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if (sino->si_linkadj) {
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sino->si_nlink--;
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if (isparent)
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sino->si_dotlinks--;
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ino_adjust(sino);
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}
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/*
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* Tell any child directories we've already removed their
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* parent. Don't try to adjust our link down again.
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*/
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if (isparent == 0)
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ino_setskip(sino, ino);
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/*
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* If we haven't yet processed this inode we need to make
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* sure we will successfully discover the lost path. If not
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* use nlinkadj to remember.
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*/
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diroff = lblktosize(fs, lbn) + dpoff;
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TAILQ_FOREACH(srec, &sino->si_recs, sr_next) {
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rrec = (struct jrefrec *)srec->sr_rec;
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if (rrec->jr_parent == ino &&
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rrec->jr_diroff == diroff)
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break;
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}
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if (srec == NULL)
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sino->si_nlinkadj++;
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ino_remref(ino, dp->d_ino, diroff, isdotdot);
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}
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}
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@ -1293,18 +1342,38 @@ ino_adjust(struct suj_ino *sino)
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struct suj_ino *stmp;
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union dinode *ip;
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nlink_t nlink;
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int recmode;
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int reqlink;
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int isdot;
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int mode;
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ino_t ino;
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nlink = sino->si_nlink;
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ino = sino->si_ino;
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mode = sino->si_mode & IFMT;
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/*
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* If it's a directory with no dot links, it was truncated before
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* the name was cleared. We need to clear the dirent that
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* points at it.
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*/
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if (mode == IFDIR && nlink == 1 && sino->si_dotlinks == 0) {
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sino->si_nlink = nlink = 0;
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TAILQ_FOREACH(srec, &sino->si_recs, sr_next) {
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rrec = (struct jrefrec *)srec->sr_rec;
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if (ino_isat(rrec->jr_parent, rrec->jr_diroff, ino,
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&recmode, &isdot) == 0)
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continue;
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ino_clrat(rrec->jr_parent, rrec->jr_diroff, ino);
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break;
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}
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if (srec == NULL)
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errx(1, "Directory %d name not found", ino);
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}
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/*
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* If it's a directory with no real names pointing to it go ahead
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* and truncate it. This will free any children.
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*/
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if ((sino->si_mode & IFMT) == IFDIR &&
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nlink - sino->si_dotlinks == 0) {
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if (mode == IFDIR && nlink - sino->si_dotlinks == 0) {
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sino->si_nlink = nlink = 0;
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/*
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* Mark any .. links so they know not to free this inode
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