Le mardi 25 janvier 2011 à 23:38 -0500, Shawn Stricker a écrit :
> Not sure where you pulled your source from but a fresh checkout of either
> master or next of
> git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-progs-unstable.git does
> not compile properly.
> They both fail with
>
> cc1: warnings being treated as errors
> disk-io.c: In function ‘btrfs_read_dev_super’:
> disk-io.c:937: error: format ‘%lu’ expects type ‘long unsigned int’, but
> argument 4 has type ‘unsigned int’
> disk-io.c:957: error: implicit declaration of function ‘uuid_unparse’
>
> am I patching/compiling from the wrong source or is there something I am
> missing?
uh, I had been compiling with CFLAGS=-g, where the makefile specifies
"-O2 -Werror"
-Werror causes warnings to be treated as errors, which is a good thing
in a way (makes sure stuff as this gets caught :) )
fixes are:
* line 937 (patched), should be %llu instead of %lu
* line 957, there should be a prototype for uuid_unparse(), most
certainly by including <uuid/uuid.h>
please try this patch instead.
Thanks for the feedback!
-- Cyrille
> On Jan 25, 2011, at 1:46 PM, Cyrille Chépélov wrote:
>
> > Hello all,
> >
> > Last Friday, the /var and /home partition on one of my appliances became
> > full. This should normally not be much of a problem, except that after
> > the incident, I had been unable to mount the partition back again.
> >
> > The appliance runs 2.6.32 as provided by Debian during the last two
> > months.
> > The rescue computer runs 2.6.37; both exhibited the same behaviour at
> > mount: an infinite loop-and-abort cycle (I unfortunately did not write
> > down the exact messages, but in a nutshell, there was not enough free
> > space to replay the log, so it aborted).
> >
> > After pulling the SD card (yes) to break the loop, I ended up with a
> > corrupt file system. Any attempt to mount, debug or fsck (using
> > btrfs-tools 0.19+20100601 as shipped by Debian, or compiled from git
> > 1b444cd2e6ab8dcafdd) aborted with the following message:
> > btrfs-debug-tree: disk-io.c:741: open_ctree_fd: Assertion `!(!
> > tree_root->node)' failed.
> >
> > After much scavenging on the disk image, I finally managed to recover,
> > using the (dirty) patch attached here. Since apparently other people had
> > similar issues, I'm posting it in the hope it might be useful.
> >
> > -- Cyrille
> >
> > PS: Chris, if btrfs-images of "before" and "after" my butcher fix would
> > be useful to you, just let me know.
> > <scavenge.patch>
>
diff --git a/btrfsck.c b/btrfsck.c
index 63e44d1..1e6bc32 100644
--- a/btrfsck.c
+++ b/btrfsck.c
@@ -2823,13 +2823,17 @@ int main(int ac, char **av)
u64 bytenr = 0;
int ret;
int num;
+ int emergency_super = 0;
while(1) {
int c;
- c = getopt(ac, av, "s:");
+ c = getopt(ac, av, "es:");
if (c < 0)
break;
switch(c) {
+ case 'e':
+ emergency_super = 1;
+ break;
case 's':
num = atol(optarg);
bytenr = btrfs_sb_offset(num);
@@ -2861,6 +2865,12 @@ int main(int ac, char **av)
if (root == NULL)
return 1;
+ if (root->fs_info->emergency_root_tree && (!emergency_super)) {
+ printf("DANGEROUS: had to use a synthetic super. Please run with '-e' flag if you know why you do it.\n");
+ printf(" ... and have perfect backups.\n");
+ return 1;
+ }
+
ret = check_extents(root);
if (ret)
goto out;
@@ -2869,6 +2879,27 @@ int main(int ac, char **av)
goto out;
ret = check_root_refs(root, &root_cache);
+ if (ret)
+ goto out;
+
+
+ if (root->fs_info->emergency_root_tree) {
+ printf("DANGEROUS: had to use a scavenged root. Apparently could figure out the primary trees ?\n"
+ " Now writing supers, knock wood.\n");
+ free_root_recs(&root_cache);
+ close_ctree(root);
+
+ cache_tree_init(&root_cache);
+ root = open_ctree(av[optind], bytenr, 1 /* WRITES! */);
+
+ ret = write_all_supers(root);
+ if (ret) {
+ printf("Error writing superblocks.\n");
+ goto out;
+ }
+ printf("Wrote back superblocks.\n");
+ }
+
out:
free_root_recs(&root_cache);
close_ctree(root);
@@ -2897,6 +2928,7 @@ out:
printf("file data blocks allocated: %llu\n referenced %llu\n",
(unsigned long long)data_bytes_allocated,
(unsigned long long)data_bytes_referenced);
+
printf("%s\n", BTRFS_BUILD_VERSION);
return ret;
}
diff --git a/ctree.h b/ctree.h
index b79e238..7439d87 100644
--- a/ctree.h
+++ b/ctree.h
@@ -728,6 +728,7 @@ struct btrfs_fs_info {
struct list_head space_info;
int system_allocs;
int readonly;
+ int emergency_root_tree;
};
/*
diff --git a/disk-io.c b/disk-io.c
index a6e1000..0b4e7f9 100644
--- a/disk-io.c
+++ b/disk-io.c
@@ -23,6 +23,7 @@
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
+#include <uuid/uuid.h>
#include <fcntl.h>
#include <unistd.h>
#include "kerncompat.h"
@@ -41,8 +42,11 @@ static int check_tree_block(struct btrfs_root *root, struct extent_buffer *buf)
struct btrfs_fs_devices *fs_devices;
int ret = 1;
- if (buf->start != btrfs_header_bytenr(buf))
+ if (buf->start != btrfs_header_bytenr(buf)) {
+ fprintf(stderr, "start place mismatch, buf says %llu btrfs_hdr says %llu\n",
+ buf->start, btrfs_header_bytenr(buf));
return ret;
+ }
fs_devices = root->fs_info->fs_devices;
while (fs_devices) {
@@ -204,16 +208,26 @@ struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
eb->dev_bytenr = multi->stripes[0].physical;
kfree(multi);
ret = read_extent_from_disk(eb);
- if (ret == 0 && check_tree_block(root, eb) == 0 &&
- csum_tree_block(root, eb, 1) == 0 &&
- verify_parent_transid(eb->tree, eb, parent_transid) == 0) {
- btrfs_set_buffer_uptodate(eb);
- return eb;
+ if (ret == 0) {
+
+ if (check_tree_block(root, eb) == 0) {
+ /* fprintf(stderr, "checked tree block %p for %p -- %llu \n", root, eb, eb->start);*/
+ if (csum_tree_block(root, eb, 1) == 0) {
+ /* fprintf(stderr, "tree block csum %p for %p--%llu is OK\n", root, eb, eb->start); */
+ if (verify_parent_transid(eb->tree, eb, parent_transid) == 0) {
+ /*fprintf(stderr, "tree block %p--%llu has correct transid, setting uptodate\n", eb, eb->start); */
+
+ btrfs_set_buffer_uptodate(eb);
+ return eb;
+ }
+ }
+ }
+
}
num_copies = btrfs_num_copies(&root->fs_info->mapping_tree,
eb->start, eb->len);
if (num_copies == 1) {
- break;
+ //break;
}
mirror_num++;
if (mirror_num > num_copies) {
@@ -581,7 +595,7 @@ struct btrfs_root *open_ctree(const char *filename, u64 sb_bytenr, int writes)
fp = open(filename, flags, 0600);
if (fp < 0) {
- fprintf (stderr, "Could not open %s\n", filename);
+ fprintf (stderr, "Could not open %s: %s\n", filename, strerror(errno));
return NULL;
}
root = open_ctree_fd(fp, filename, sb_bytenr, writes);
@@ -590,6 +604,102 @@ struct btrfs_root *open_ctree(const char *filename, u64 sb_bytenr, int writes)
return root;
}
+#define MAX_EMERG_BUCKETS 30
+static int try_emergency_tree_fixup(struct btrfs_super_block *disk_super,
+ struct btrfs_root *chunk_root,
+ struct btrfs_root *tree_root)
+{
+ struct btrfs_header* buf;
+ u64 ofs, oldofs;
+ u32 blocksize;
+ u64 generation;
+ int ret, i;
+
+ u64 best_gen[MAX_EMERG_BUCKETS];
+ u64 best_bytenr[MAX_EMERG_BUCKETS];
+
+ memset(&best_gen, 0, sizeof(best_gen));
+ memset(&best_bytenr, 0, sizeof(best_bytenr));
+
+ blocksize = btrfs_level_size(tree_root,
+ btrfs_super_chunk_root_level(disk_super));
+ generation = btrfs_super_chunk_root_generation(disk_super);
+ buf = (struct btrfs_header*)malloc(blocksize);
+
+ oldofs = btrfs_super_bytenr(disk_super);
+ for (ofs = oldofs;
+ ofs < btrfs_super_total_bytes(disk_super);
+ ofs += blocksize) {
+
+ ret = pread(chunk_root->node->fd, buf, blocksize, ofs);
+ if (ret == blocksize) {
+ u64 blockofs = le64_to_cpu(buf->bytenr);
+ if (blockofs != ofs) continue;
+
+ char* src = chunk_root->node->data + (long)btrfs_header_fsid(chunk_root->node);
+ char* dst = (char*) &(buf->fsid);
+ if (memcmp(src, dst, sizeof(buf->fsid)) != 0)
+ continue;
+
+ u64 blockgen = le64_to_cpu(buf->generation);
+ u64 blockowner = le64_to_cpu(buf->owner);
+ u32 blocknritems = le32_to_cpu(buf->nritems);
+ u8 blocklevel = le8_to_cpu(buf->level);
+
+ /*
+ fprintf(stderr,
+ " found valid header at %llu(+%llu) -- gen=%llu owner=%llu nritems=%u level=%u ",
+ ofs, ofs-oldofs, blockgen, blockowner, blocknritems, blocklevel);
+ */
+
+ if ((blockowner < 0ull) && (blockowner > -11ull)) { blockowner += 30; /* hack */ }
+
+ if ((blockowner >= 0) && (blockowner < MAX_EMERG_BUCKETS)) {
+ if (blockgen > best_gen[blockowner]) {
+ best_gen[blockowner] = blockgen;
+ best_bytenr[blockowner] = ofs;
+
+ fprintf(stderr,
+ " found valid header at %llu(+%llu) -- gen=%llu owner=%llu nritems=%u level=%u ",
+ ofs, ofs-oldofs, blockgen, blockowner, blocknritems, blocklevel);
+
+ fprintf(stderr,
+ " ... new best gen for ObjectID %llu at %llu\n", blockowner, ofs);
+ } else {
+ }
+ } else {
+ }
+
+ oldofs = ofs;
+ }
+ }
+ fprintf(stderr,"*** done scanning, at offset %llu ***\n", ofs);
+ for ( i = 0; i < MAX_EMERG_BUCKETS; ++i) {
+ fprintf(stderr," for ObjectID: %d, max gen=%llu at %llu\n", i, best_gen[i], best_bytenr[i]);
+ }
+
+
+ free(buf);
+
+#if 1
+ if (best_gen[BTRFS_CSUM_TREE_OBJECTID] == best_gen[BTRFS_ROOT_TREE_OBJECTID]) {
+ /* now we try to do the repair */
+ fprintf(stderr,
+ " ATTEMPTING DANGEROUS REPAIR with root gen=%llu bytenr=%llu\n",
+ best_gen[BTRFS_ROOT_TREE_OBJECTID], best_bytenr[BTRFS_ROOT_TREE_OBJECTID]);
+ btrfs_set_super_generation(disk_super, best_gen[BTRFS_ROOT_TREE_OBJECTID]);
+ btrfs_set_super_root(disk_super, best_bytenr[BTRFS_ROOT_TREE_OBJECTID]);
+
+ /* not actually changing the on-disk super. Debug should proceed,
+ fsck should eventually rewrite the super ?*/
+ tree_root->fs_info->emergency_root_tree = 1;
+ return 0;
+ }
+#endif
+
+ return 1; /* nothing done */
+}
+
struct btrfs_root *open_ctree_fd(int fp, const char *path, u64 sb_bytenr,
int writes)
{
@@ -736,7 +846,26 @@ struct btrfs_root *open_ctree_fd(int fp, const char *path, u64 sb_bytenr,
tree_root->node = read_tree_block(tree_root,
btrfs_super_root(disk_super),
blocksize, generation);
+ if (!tree_root->node) {
+ fprintf(stderr,"*** did not find a root, about to abort ***\n");
+ fprintf(stderr,"*** will attempt to find useful trees before bailing out anyway: ***\n");
+ ret = try_emergency_tree_fixup(disk_super, chunk_root, tree_root);
+ if (!ret) {
+ fprintf(stderr,"a repair happened, trying again (once):\n");
+
+ generation = btrfs_super_generation(disk_super);
+ tree_root->node = read_tree_block(tree_root,
+ btrfs_super_root(disk_super),
+ blocksize, generation);
+ if (!tree_root->node) {
+ fprintf(stderr,"*** again, did not find a root, about to abort, for good. ***\n");
+ }
+ }
+ }
BUG_ON(!tree_root->node);
+ if (!tree_root->node) {
+ fprintf(stderr,"*** huh? ***\n");
+ }
ret = find_and_setup_root(tree_root, fs_info,
BTRFS_EXTENT_TREE_OBJECTID, extent_root);
BUG_ON(ret);
@@ -774,12 +903,15 @@ struct btrfs_root *open_ctree_fd(int fp, const char *path, u64 sb_bytenr,
int btrfs_read_dev_super(int fd, struct btrfs_super_block *sb, u64 sb_bytenr)
{
u8 fsid[BTRFS_FSID_SIZE];
+ char up_fsid[37], up_ofsid[37];
struct btrfs_super_block buf;
int i;
int ret;
u64 transid = 0;
u64 bytenr;
+
+
if (sb_bytenr != BTRFS_SUPER_INFO_OFFSET) {
ret = pread64(fd, &buf, sizeof(buf), sb_bytenr);
if (ret < sizeof(buf))
@@ -796,24 +928,63 @@ int btrfs_read_dev_super(int fd, struct btrfs_super_block *sb, u64 sb_bytenr)
for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
bytenr = btrfs_sb_offset(i);
+ fprintf(stderr, "trying potential super #%d at bytenr %llu \n",
+ i, bytenr);
+
+
ret = pread64(fd, &buf, sizeof(buf), bytenr);
- if (ret < sizeof(buf))
+ if (ret < sizeof(buf)) {
+ fprintf(stderr, " got only %d bytes instead of %lu\n",
+ ret, sizeof(buf));
break;
+ }
- if (btrfs_super_bytenr(&buf) != bytenr ||
- strncmp((char *)(&buf.magic), BTRFS_MAGIC,
- sizeof(buf.magic)))
+
+ if (btrfs_super_bytenr(&buf) != bytenr) {
+ fprintf(stderr, " misplaced block thinks it's at %llu\n",
+ btrfs_super_bytenr(&buf));
+ continue;
+ }
+
+ if (strncmp((char *)(&buf.magic), BTRFS_MAGIC,
+ sizeof(buf.magic))) {
+ fprintf(stderr, " invalid magic\n");
continue;
+ }
if (i == 0)
memcpy(fsid, buf.fsid, sizeof(fsid));
- else if (memcmp(fsid, buf.fsid, sizeof(fsid)))
+ else if (memcmp(fsid, buf.fsid, sizeof(fsid))) {
+ uuid_unparse(fsid, up_fsid);
+ uuid_unparse(buf.fsid, up_ofsid);
+ fprintf(stderr, " wrong fsid %s expected %s \n", up_fsid, up_ofsid);
+
continue;
+ }
+
+ if (btrfs_super_generation(&buf) < transid) {
+ fprintf(stderr, "super #%d at bytenr %llu has older generation %llu than %llu, skipping\n",
+ i, bytenr, btrfs_super_generation(&buf), transid);
+ continue;
+ }
+
+ if (btrfs_super_generation(&buf) == transid) {
+ fprintf(stderr, "super #%d at bytenr %llu has same generation %llu than %llu, skipping\n",
+ i, bytenr, btrfs_super_generation(&buf), transid);
- if (btrfs_super_generation(&buf) > transid) {
- memcpy(sb, &buf, sizeof(*sb));
- transid = btrfs_super_generation(&buf);
+ if (memcmp(sb, &buf, sizeof(*sb))) {
+ fprintf(stderr, " warning: super #%d at bytenr %llu has different contents!\n",
+ i, bytenr);
+ }
+ continue;
}
+
+ /* btrfs_super_generation(&buf) > transid */
+ fprintf(stderr, "super #%d at bytenr %llu has better generation %llu than %llu, using that\n",
+ i, bytenr, btrfs_super_generation(&buf), transid);
+
+ memcpy(sb, &buf, sizeof(*sb));
+ transid = btrfs_super_generation(&buf);
}
return transid > 0 ? 0 : -1;
@@ -930,7 +1101,12 @@ static int close_all_devices(struct btrfs_fs_info *fs_info)
struct list_head *next;
struct btrfs_device *device;
- return 0;
+ if (!fs_info->emergency_root_tree) {
+ /* huh? there was a "return 0" sitting here. Yes we leaked fd's.
+ Leaving it on when not doing funky desperate things.
+ */
+ return 0;
+ }
list = &fs_info->fs_devices->devices;
list_for_each(next, list) {
diff --git a/disk-io.h b/disk-io.h
index 49e5692..0af98b4 100644
--- a/disk-io.h
+++ b/disk-io.h
@@ -64,6 +64,7 @@ int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid);
int btrfs_set_buffer_uptodate(struct extent_buffer *buf);
int wait_on_tree_block_writeback(struct btrfs_root *root,
struct extent_buffer *buf);
+int write_all_supers(struct btrfs_root *root);
u32 btrfs_csum_data(struct btrfs_root *root, char *data, u32 seed, size_t len);
void btrfs_csum_final(u32 crc, char *result);
