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dm integrity: add recovery mode

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In recovery mode, we don't:
- replay the journal
- check checksums
- allow writes to the device

This mode can be used as a last resort for data recovery.  The
motivation for recovery mode is that when there is a single error in the
journal, the user should not lose access to the whole device.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Mikulas Patocka
2017-03-17 12:40:51 -04:00
committed by Mike Snitzer
parent 1aa0efd421
commit c2bcb2b702
2 changed files with 32 additions and 13 deletions
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40
drivers/md/dm-integrity.c
View File

@@ -1216,6 +1216,9 @@ static void integrity_metadata(struct work_struct *w)
unsigned sectors_to_process = dio->range.n_sectors;
sector_t sector = dio->range.logical_sector;
if (unlikely(ic->mode == 'R'))
goto skip_io;
checksums = kmalloc((PAGE_SIZE >> SECTOR_SHIFT) * ic->tag_size + extra_space,
GFP_NOIO | __GFP_NORETRY | __GFP_NOWARN);
if (!checksums)
@@ -1288,6 +1291,7 @@ again:
}
}
}
skip_io:
dec_in_flight(dio);
return;
error:
@@ -1327,6 +1331,9 @@ static int dm_integrity_map(struct dm_target *ti, struct bio *bio)
return -EIO;
}
if (unlikely(ic->mode == 'R') && unlikely(dio->write))
return -EIO;
get_area_and_offset(ic, dio->range.logical_sector, &area, &offset);
dio->metadata_block = get_metadata_sector_and_offset(ic, area, offset, &dio->metadata_offset);
bio->bi_iter.bi_sector = get_data_sector(ic, area, offset);
@@ -1926,6 +1933,9 @@ static void replay_journal(struct dm_integrity_c *ic)
bool journal_empty;
unsigned char unused, last_used, want_commit_seq;
if (ic->mode == 'R')
return;
if (ic->journal_uptodate)
return;
@@ -2705,7 +2715,7 @@ static int dm_integrity_ctr(struct dm_target *ti, unsigned argc, char **argv)
}
}
if (!strcmp(argv[3], "J") || !strcmp(argv[3], "D"))
if (!strcmp(argv[3], "J") || !strcmp(argv[3], "D") || !strcmp(argv[3], "R"))
ic->mode = argv[3][0];
else {
ti->error = "Invalid mode (expecting J or D)";
@@ -2864,14 +2874,15 @@ static int dm_integrity_ctr(struct dm_target *ti, unsigned argc, char **argv)
ti->error = "Error reading superblock";
goto bad;
}
if (!memcmp(ic->sb->magic, SB_MAGIC, 8)) {
should_write_sb = false;
} else {
for (i = 0; i < 512; i += 8) {
if (*(__u64 *)((__u8 *)ic->sb + i)) {
r = -EINVAL;
ti->error = "The device is not initialized";
goto bad;
should_write_sb = false;
if (memcmp(ic->sb->magic, SB_MAGIC, 8)) {
if (ic->mode != 'R') {
for (i = 0; i < 512; i += 8) {
if (*(__u64 *)((__u8 *)ic->sb + i)) {
r = -EINVAL;
ti->error = "The device is not initialized";
goto bad;
}
}
}
@@ -2880,7 +2891,8 @@ static int dm_integrity_ctr(struct dm_target *ti, unsigned argc, char **argv)
ti->error = "Could not initialize superblock";
goto bad;
}
should_write_sb = true;
if (ic->mode != 'R')
should_write_sb = true;
}
if (ic->sb->version != SB_VERSION) {
@@ -2954,9 +2966,11 @@ static int dm_integrity_ctr(struct dm_target *ti, unsigned argc, char **argv)
}
dm_bufio_set_sector_offset(ic->bufio, ic->start + ic->initial_sectors);
r = create_journal(ic, &ti->error);
if (r)
goto bad;
if (ic->mode != 'R') {
r = create_journal(ic, &ti->error);
if (r)
goto bad;
}
if (should_write_sb) {
int r;