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Improve handling of missing '.' and '..' in UFS directories.

Browse Source 
The UFS filesystem expects to find '.' and '..' as the first two entries
in a directory. The kernel's UFS name cache can become quite confused
when these two entries are not present as the first two entries.

Prior to this change, when the fsck_ffs(8) utility detected that
'.' and/or '..' were missing, it would report them, but only offered
to replace them if the space at the beginning of the directory was
available. Otherwise it was left to the system administrator to
move the offending file(s) out of the way and then rerun fsck_ffs(8)
to create the '.' and '..' entries.

With this change, fsck_ffs(8) will always be able to create the '.'
and/or '..' entries. It moves any files in the way elsewhere in the
directory block. If there is no room in the directory block to which
to move them, they are placed in the lost+found directory.

Reported by:  Peter Holm
Sponsored by: The FreeBSD Foundation
This commit is contained in:
Kirk McKusick 2022-08-17 14:19:59 -07:00
parent 4f9606c9a6
commit 6bae6625e0
1 changed files with 82 additions and 45 deletions
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111
sbin/fsck_ffs/pass2.c
View File

@ -217,9 +217,9 @@ pass2(void)
continue;
if (inp->i_dotdot == 0) {
inp->i_dotdot = inp->i_parent;
fileerror(inp->i_parent, inp->i_number, "MISSING '..'");
if (reply("FIX") == 0)
continue;
if (debug)
fileerror(inp->i_parent, inp->i_number,
"DEFERRED MISSING '..' FIX");
(void)makeentry(inp->i_number, inp->i_parent, "..");
inoinfo(inp->i_parent)->ino_linkcnt--;
continue;
@ -289,7 +289,7 @@ pass2check(struct inodesc *idesc)
struct inode ip;
union dinode *dp;
const char *errmsg;
struct direct proto;
struct direct proto, *newdirp;
/*
* check for "."
@ -301,44 +301,51 @@ pass2check(struct inodesc *idesc)
if (dirp->d_ino != 0 && strcmp(dirp->d_name, ".") == 0) {
if (dirp->d_ino != idesc->id_number) {
direrror(idesc->id_number, "BAD INODE NUMBER FOR '.'");
if (reply("FIX") == 1) {
dirp->d_ino = idesc->id_number;
if (reply("FIX") == 1)
ret |= ALTERED;
}
}
if (dirp->d_type != DT_DIR) {
direrror(idesc->id_number, "BAD TYPE VALUE FOR '.'");
if (reply("FIX") == 1) {
dirp->d_type = DT_DIR;
if (reply("FIX") == 1)
ret |= ALTERED;
}
}
goto chk1;
}
direrror(idesc->id_number, "MISSING '.'");
proto.d_ino = idesc->id_number;
proto.d_type = DT_DIR;
proto.d_namlen = 1;
(void)strcpy(proto.d_name, ".");
entrysize = DIRSIZ(0, &proto);
if (dirp->d_ino != 0 && strcmp(dirp->d_name, "..") != 0) {
pfatal("CANNOT FIX, FIRST ENTRY IN DIRECTORY CONTAINS %s\n",
direrror(idesc->id_number, "MISSING '.'");
errmsg = "ADD '.' ENTRY";
if (dirp->d_reclen < entrysize + DIRSIZ(0, dirp)) {
/* Not enough space to add '.', replace first entry with '.' */
if (dirp->d_ino != 0) {
pwarn("\nFIRST ENTRY IN DIRECTORY CONTAINS %s\n",
dirp->d_name);
} else if (dirp->d_reclen < entrysize) {
pfatal("CANNOT FIX, INSUFFICIENT SPACE TO ADD '.'\n");
} else if (dirp->d_reclen < 2 * entrysize) {
errmsg = "REPLACE WITH '.'";
}
if (reply(errmsg) == 0)
goto chk1;
proto.d_reclen = dirp->d_reclen;
memmove(dirp, &proto, (size_t)entrysize);
if (reply("FIX") == 1)
ret |= ALTERED;
} else {
n = dirp->d_reclen - entrysize;
/* Move over first entry and add '.' entry */
if (reply(errmsg) == 0)
goto chk1;
newdirp = (struct direct *)((char *)(dirp) + entrysize);
dirp->d_reclen -= entrysize;
memmove(newdirp, dirp, dirp->d_reclen);
proto.d_reclen = entrysize;
memmove(dirp, &proto, (size_t)entrysize);
idesc->id_entryno++;
inoinfo(dirp->d_ino)->ino_linkcnt--;
dirp = (struct direct *)((char *)(dirp) + entrysize);
memset(dirp, 0, (size_t)n);
dirp->d_reclen = n;
if (reply("FIX") == 1)
inoinfo(idesc->id_number)->ino_linkcnt--;
dirp = newdirp;
ret |= ALTERED;
}
chk1:
@ -372,30 +379,60 @@ chk1:
}
goto chk2;
}
if (dirp->d_ino != 0 && strcmp(dirp->d_name, ".") != 0) {
fileerror(inp->i_parent, idesc->id_number, "MISSING '..'");
pfatal("CANNOT FIX, SECOND ENTRY IN DIRECTORY CONTAINS %s\n",
fileerror(inp->i_parent != 0 ? inp->i_parent : idesc->id_number,
idesc->id_number, "MISSING '..'");
errmsg = "ADD '..' ENTRY";
if (dirp->d_reclen < entrysize + DIRSIZ(0, dirp)) {
/* No space to add '..', replace second entry with '..' */
if (dirp->d_ino != 0) {
pfatal("SECOND ENTRY IN DIRECTORY CONTAINS %s\n",
dirp->d_name);
errmsg = "REPLACE WITH '..'";
}
if (reply(errmsg) == 0) {
inp->i_dotdot = (ino_t)-1;
} else if (dirp->d_reclen < entrysize) {
fileerror(inp->i_parent, idesc->id_number, "MISSING '..'");
pfatal("CANNOT FIX, INSUFFICIENT SPACE TO ADD '..'\n");
inp->i_dotdot = (ino_t)-1;
} else if (inp->i_parent != 0) {
/*
* We know the parent, so fix now.
*/
inp->i_dotdot = inp->i_parent;
fileerror(inp->i_parent, idesc->id_number, "MISSING '..'");
goto chk2;
}
if (proto.d_ino == 0) {
/* Defer processing until parent known */
idesc->id_entryno++;
if (debug)
printf("(FIX DEFERRED)\n");
}
inp->i_dotdot = proto.d_ino;
proto.d_reclen = dirp->d_reclen;
memmove(dirp, &proto, (size_t)entrysize);
if (reply("FIX") == 1)
ret |= ALTERED;
} else {
/* Move over second entry and add '..' entry */
if (reply(errmsg) == 0) {
inp->i_dotdot = (ino_t)-1;
goto chk2;
}
if (proto.d_ino == 0) {
/* Defer processing until parent known */
idesc->id_entryno++;
if (debug)
printf("(FIX DEFERRED)\n");
}
inp->i_dotdot = proto.d_ino;
if (dirp->d_ino == 0) {
proto.d_reclen = dirp->d_reclen;
memmove(dirp, &proto, (size_t)entrysize);
} else {
newdirp = (struct direct *)((char *)(dirp) + entrysize);
dirp->d_reclen -= entrysize;
memmove(newdirp, dirp, dirp->d_reclen);
proto.d_reclen = entrysize;
memmove(dirp, &proto, (size_t)entrysize);
if (dirp->d_ino != 0) {
idesc->id_entryno++;
inoinfo(dirp->d_ino)->ino_linkcnt--;
}
dirp = newdirp;
}
ret |= ALTERED;
}
idesc->id_entryno++;
if (dirp->d_ino != 0)
inoinfo(dirp->d_ino)->ino_linkcnt--;
return (ret|KEEPON);
chk2:
if (dirp->d_ino == 0)
return (ret|KEEPON);