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Tolerate device-id changes (due to automounter) amid copying #5

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233 changes: 184 additions & 49 deletions src/cpdup.c
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Original file line number Diff line number Diff line change
Expand Up @@ -94,16 +94,15 @@ struct hlink {
char name[];
};

typedef struct copy_info {
char *spath;
char *dpath;
dev_t sdevNo;
dev_t ddevNo;
} *copy_info_t;
struct pathinfo {
char *path;
dev_t devno;
unsigned int generation;
};

static struct hlink *hltable[HLSIZE];

static void RemoveRecur(const char *dpath, dev_t devNo, struct stat *dstat);
static void RemoveRecur(const char *dpath, struct stat *dstat);
static void InitList(List *list);
static void ResetList(List *list);
static Node *IterateList(List *list, Node *node, int n);
Expand All @@ -130,12 +129,16 @@ static int xrename(const char *src, const char *dst, u_long flags);
static int xlink(const char *src, const char *dst, u_long flags);
static int xremove(struct HostConf *host, const char *path);
static int xrmdir(struct HostConf *host, const char *path);
static int DoCopy(copy_info_t info, struct stat *stat1, int depth);
static int DoCopy(const char *spath, const char *dpath, struct stat *stat1,
int depth);
static int ScanDir(List *list, struct HostConf *host, const char *path,
int64_t *CountReadBytes, int n);
static int mtimecmp(struct stat *st1, struct stat *st2);
static int symlink_mfo_test(struct HostConf *hc, struct stat *st1,
struct stat *st2);
static int _pd_init(struct pathinfo *pPI, struct HostConf *pHost, char *path);
static int pd_init(char *srcpath, char *dstpath);
static int pd_changed(dev_t target_devno, int is_src);

int AskConfirmation = 1;
int SafetyOpt = 1;
Expand Down Expand Up @@ -177,6 +180,9 @@ int64_t CountLinkedItems;
static struct HostConf SrcHost;
static struct HostConf DstHost;

static struct pathinfo _sinfo;
static struct pathinfo _dinfo;

int
main(int ac, char **av)
{
Expand All @@ -186,7 +192,6 @@ main(int ac, char **av)
char *dst = NULL;
char *ptr;
struct timeval start;
struct copy_info info;

signal(SIGPIPE, SIG_IGN);

Expand Down Expand Up @@ -349,20 +354,13 @@ main(int ac, char **av)
fprintf(stderr, "Group[%d] == %d\n", i, GroupList[i]);
#endif

bzero(&info, sizeof(info));
pd_init(src, dst);

if (dst) {
DstBaseLen = strlen(dst);
info.spath = src;
info.dpath = dst;
info.sdevNo = (dev_t)-1;
info.ddevNo = (dev_t)-1;
i = DoCopy(&info, NULL, -1);
i = DoCopy(src, dst, NULL, -1);
} else {
info.spath = src;
info.dpath = NULL;
info.sdevNo = (dev_t)-1;
info.ddevNo = (dev_t)-1;
i = DoCopy(&info, NULL, -1);
i = DoCopy(src, dst, NULL, -1);
}
#ifndef NOMD5
md5_flush();
Expand Down Expand Up @@ -407,6 +405,143 @@ main(int ac, char **av)
exit((i == 0) ? 0 : 1);
}

/*
* Initialize device number for a single path.
*
* The destination's path might not exist when we start, so we might
* have to try again later. Therefore, always store the path because
* caller pd_changed() won't know the top path.
*/
static int _pd_init(struct pathinfo *pPI, struct HostConf *pHost, char *path)
{
struct stat st;

/*
* save path so we can redo stat later if it fails now
*/
if (path) {
if (pPI->path) {
free(pPI->path);
pPI->path = NULL;
}
pPI->path = malloc(strlen(path) + 1);
strcpy(pPI->path, path);
} else {
/*
* NULL path parameter means "use previously-initialized path"
* so it's an error if there isn't a previous path.
*/
assert(pPI->path);
if (VerboseOpt >= 3)
logstd("%s: retrying cached path %s\n", __func__, pPI->path);
}

if (hc_lstat(pHost, pPI->path, &st) != 0) {
/* if destination doesn't exist yet, failure here is expected */
if (VerboseOpt >= 3)
logstd("%s: hc_lstat(%s) failed\n", __func__, pPI->path);
return -1;
}
pPI->devno = st.st_dev;
++(pPI->generation);
return 0;
}

/*
* Attempt to look up src and dst top-level device numbers
* at program start.
*/
static int
pd_init(char *srcpath, char *dstpath)
{
if (VerboseOpt >= 2)
logstd("%s: src %s, dst %s\n", __func__,
(srcpath? srcpath: "NIL"), (dstpath? dstpath: "NIL"));
if (srcpath)
if (_pd_init(&_sinfo, &SrcHost, srcpath))
return -1;
if (dstpath)
if (_pd_init(&_dinfo, &DstHost, dstpath))
return -1;
return 0;
}

/*
* Check target_devno (target device number) to see if it is on
* the same device as the top of the tree. If the target device number
* is different, then the target is on a different mounted device.
*
* RETURN VALUES:
*
* 0 same device id: did not cross mount point
* 1 different device id: DID cross mount point
* -1 error
*
* This function re-does the stat call on the top of the file tree
* every time it discovers a different device number for <path>
* because automounted volumes can be assigned new device numbers
* (due to unmount/remount) while we are copying.
*/
static int
pd_changed(dev_t target_devno, int is_src)
{
struct pathinfo *pTPI = is_src? &_sinfo: &_dinfo;
struct HostConf *pHost = is_src? &SrcHost: &DstHost;

if (VerboseOpt >= 4)
logstd("%s: target devno 0x%lx, is_src %u\n", __func__,
target_devno, is_src);

/* initialized? */
if (!pTPI->generation && !is_src) {
/*
* Destination devno could be uninitialized if it didn't
* exist at program startup. Retry here with cached path.
*/
if (VerboseOpt >= 3)
logstd("%s: retrying dst devno initialization\n", __func__);
_pd_init(&_dinfo, &DstHost, NULL);
}
assert(pTPI->generation);

if (target_devno != pTPI->devno) {
struct stat stTop;

/*
* Different device number. Either we really did cross a
* mount point, or we are on an automounted volume that
* got remounted. Recheck top path to see if it changed.
*/
if (hc_lstat(pHost, pTPI->path, &stTop) != 0) {
logerr("%s: failed: hc_lstat(%s)\n", __func__, pTPI->path);
return -1;
}
if (stTop.st_dev != pTPI->devno) {
/*
* Remount case: update our notion of top device id.
*/
if (VerboseOpt >= 2)
logstd("%s: %s Top devno changed: old 0x%lx, new 0x%lx\n",
__func__, (is_src? "src": "dst"),
pTPI->devno, stTop.st_dev);

++(pTPI->generation);
pTPI->devno = stTop.st_dev;

/* updated top device number is same as <path> device number */
if (target_devno == pTPI->devno)
return 0;
}
if (VerboseOpt >= 2)
logstd("%s: %s devno differs: top 0x%lx, path 0x%lx\n",
__func__, (is_src? "src": "dst"),
pTPI->devno, target_devno);
return 1;
}

return 0;
}

static int
getbool(const char *str)
{
Expand Down Expand Up @@ -679,16 +814,13 @@ validate_check(const char *spath, const char *dpath)
}

int
DoCopy(copy_info_t info, struct stat *stat1, int depth)
DoCopy(const char *spath, const char *dpath, struct stat *stat1, int depth)
{
const char *spath = info->spath;
const char *dpath = info->dpath;
dev_t sdevNo = info->sdevNo;
dev_t ddevNo = info->ddevNo;
struct stat st1;
struct stat st2;
unsigned long st2_flags;
int r, mres, fres, st2Valid;
int rc;
struct hlink *hln;
uint64_t size;

Expand Down Expand Up @@ -885,7 +1017,7 @@ DoCopy(copy_info_t info, struct stat *stat1, int depth)
((dpath) ? dpath : spath), "");
}
if (dpath)
RemoveRecur(dpath, ddevNo, &st2);
RemoveRecur(dpath, &st2);
st2Valid = 0;
}

Expand Down Expand Up @@ -947,10 +1079,13 @@ DoCopy(copy_info_t info, struct stat *stat1, int depth)
* When copying a directory, stop if the source crosses a mount
* point.
*/
if (sdevNo != (dev_t)-1 && stat1->st_dev != sdevNo)
rc = pd_changed(stat1->st_dev, 1 /* is_src */);
if (rc > 0) {
skipdir = 1;
else
sdevNo = stat1->st_dev;
} else if (rc < 0) {
r = 1;
goto done;
}

/*
* When copying a directory, stop if the destination crosses
Expand All @@ -961,15 +1096,17 @@ DoCopy(copy_info_t info, struct stat *stat1, int depth)
* as a flag. If the stat failed st2 will still only have its
* default initialization.
*
* So we simply assume here that the directory is within the
* current target mount if we had to create it (aka st2Valid is 0)
* and we leave ddevNo alone.
* We assume here that the directory is within the current
* target mount if we had to create it (aka st2Valid is 0).
*/
if (st2Valid) {
if (ddevNo != (dev_t)-1 && st2.st_dev != ddevNo)
rc = pd_changed(st2.st_dev, 0 /* is_src */);
if (rc > 0) {
skipdir = 1;
else
ddevNo = st2.st_dev;
} else if (rc < 0) {
r = 1;
goto done;
}
}

if (!skipdir) {
Expand All @@ -989,19 +1126,13 @@ DoCopy(copy_info_t info, struct stat *stat1, int depth)
if (dpath)
ndpath = mprintf("%s/%s", dpath, node->no_Name);

info->spath = nspath;
info->dpath = ndpath;
info->sdevNo = sdevNo;
info->ddevNo = ddevNo;
if (depth < 0)
r += DoCopy(info, node->no_Stat, depth);
r += DoCopy(nspath, ndpath, node->no_Stat, depth);
else
r += DoCopy(info, node->no_Stat, depth + 1);
r += DoCopy(nspath, ndpath, node->no_Stat, depth + 1);
free(nspath);
if (ndpath)
free(ndpath);
info->spath = NULL;
info->dpath = NULL;
}

/*
Expand All @@ -1019,7 +1150,7 @@ DoCopy(copy_info_t info, struct stat *stat1, int depth)
char *ndpath;

ndpath = mprintf("%s/%s", dpath, node->no_Name);
RemoveRecur(ndpath, ddevNo, node->no_Stat);
RemoveRecur(ndpath, node->no_Stat);
free(ndpath);
}
}
Expand Down Expand Up @@ -1460,18 +1591,22 @@ ScanDir(List *list, struct HostConf *host, const char *path,
*/

static void
RemoveRecur(const char *dpath, dev_t devNo, struct stat *dstat)
RemoveRecur(const char *dpath, struct stat *dstat)
{
struct stat st;
int rc;

if (dstat == NULL) {
if (hc_lstat(&DstHost, dpath, &st) == 0)
dstat = &st;
}
if (dstat != NULL) {
if (devNo == (dev_t)-1)
devNo = dstat->st_dev;
if (dstat->st_dev == devNo) {
rc = pd_changed(dstat->st_dev, 0 /* is_src */);
if (rc < 0) {
logerr("%s: pd_changed failed, skipping remove operation\n",
__func__);
return;
} else if (rc == 0) {
if (S_ISDIR(dstat->st_mode)) {
DIR *dir;

Expand All @@ -1493,7 +1628,7 @@ RemoveRecur(const char *dpath, dev_t devNo, struct stat *dstat)
char *ndpath;

ndpath = mprintf("%s/%s", dpath, node->no_Name);
RemoveRecur(ndpath, devNo, node->no_Stat);
RemoveRecur(ndpath, node->no_Stat);
free(ndpath);
}
ResetList(list);
Expand Down