diff options
| -rw-r--r-- | lib/format_text/format-text.c | 8 | ||||
| -rw-r--r-- | lib/format_text/text_label.c | 35 | ||||
| -rw-r--r-- | lib/label/label.c | 5 | ||||
| -rw-r--r-- | lib/label/label.h | 1 |
4 files changed, 49 insertions, 0 deletions
diff --git a/lib/format_text/format-text.c b/lib/format_text/format-text.c index 64ad4677c..dd550a6eb 100644 --- a/lib/format_text/format-text.c +++ b/lib/format_text/format-text.c @@ -1563,6 +1563,14 @@ int read_metadata_location_summary(const struct format_type *fmt, return 0; } + /* + * This code reading the start of the metadata area and verifying that + * it looks like a vgname can be removed. The checksum verifies it. + */ + log_debug_metadata("Reading metadata_vgname summary from %s at %llu", + dev_name(dev_area->dev), + (unsigned long long)(dev_area->start + rlocn->offset)); + memset(namebuf, 0, sizeof(namebuf)); if (!dev_read_bytes(dev_area->dev, dev_area->start + rlocn->offset, NAME_LEN, namebuf)) diff --git a/lib/format_text/text_label.c b/lib/format_text/text_label.c index be5195039..7bc7a1ed3 100644 --- a/lib/format_text/text_label.c +++ b/lib/format_text/text_label.c @@ -327,6 +327,9 @@ static int _read_mda_header_and_metadata(const struct format_type *fmt, { struct mda_context *mdac = (struct mda_context *) mda->metadata_locn; struct mda_header *mdah; + int retries = 0; + + retry: if (!(mdah = raw_read_mda_header(fmt, &mdac->area, (mda->mda_num == 1), 0, bad_fields))) { log_warn("WARNING: bad metadata header on %s at %llu.", @@ -354,6 +357,38 @@ static int _read_mda_header_and_metadata(const struct format_type *fmt, if (vgsummary->zero_offset) return 1; + /* + * This code is used by label_scan to get a summary of the + * VG metadata that will be properly read later by vg_read. + * The initial read of this device during label_scan + * populates bcache with the first 128K of data from the + * device. That block of data contains the mda_header + * (at 4k) but will often not include the metadata text, + * which is often located further into the metadata area + * (beyond the 128K block saved in bcache.) + * So read_metadata_location_summary will usually get the + * mda_header from bcache which was read initially, and + * then it will often need to do a new disk read to get + * the actual metadata text that the mda_header points to. + * Since there is no locking around label_scan, it's + * possible (but very rare) that the entire metadata area + * can be rewritten by other commands between the time that + * this command read the mda_header and the time that it + * reads the metadata text. This means the expected metadata + * text isn't found, and an error is returned here. + * To handle this, invalidate all data in bcache for this + * device and reread the mda_header and metadata text back to + * back, so inconsistency is less likely (without locking + * there's no guarantee, e.g. if the command is blocked + * somehow between the two reads.) + */ + if (!retries) { + log_print("Retrying metadata scan."); + retries++; + dev_invalidate(mdac->area.dev); + goto retry; + } + log_warn("WARNING: bad metadata text on %s in mda%d", dev_name(mdac->area.dev), mda->mda_num); *bad_fields |= BAD_MDA_TEXT; diff --git a/lib/label/label.c b/lib/label/label.c index 50107edc8..ac84b6293 100644 --- a/lib/label/label.c +++ b/lib/label/label.c @@ -1704,6 +1704,11 @@ bool dev_invalidate_bytes(struct device *dev, uint64_t start, size_t len) return bcache_invalidate_bytes(scan_bcache, dev->bcache_di, start, len); } +void dev_invalidate(struct device *dev) +{ + bcache_invalidate_di(scan_bcache, dev->bcache_di); +} + bool dev_write_zeros(struct device *dev, uint64_t start, size_t len) { return dev_set_bytes(dev, start, len, 0); diff --git a/lib/label/label.h b/lib/label/label.h index fcdc309ac..32ceebc34 100644 --- a/lib/label/label.h +++ b/lib/label/label.h @@ -130,6 +130,7 @@ bool dev_write_bytes(struct device *dev, uint64_t start, size_t len, void *data) bool dev_write_zeros(struct device *dev, uint64_t start, size_t len); bool dev_set_bytes(struct device *dev, uint64_t start, size_t len, uint8_t val); bool dev_invalidate_bytes(struct device *dev, uint64_t start, size_t len); +void dev_invalidate(struct device *dev); void dev_set_last_byte(struct device *dev, uint64_t offset); void dev_unset_last_byte(struct device *dev); |