libata: during revalidation, check n_sectors after device is configured

Device might be resized during ata_dev_configure() due to HPA or
(later) ACPI _GTF.  Currently it's worked around by caching n_sectors
before turning off HPA.  The cached original size is overwritten if
the device is reconfigured without being hardreset - which always
happens after configuring trasnfer mode.  If the device gets hardreset
for some reason after that, revalidation fails with -ENODEV.

This patch makes size checking more robust by moving n_sectors check
from ata_dev_reread_id() to ata_dev_revalidate() after the device is
fully configured.  No matter what happens during configuration, a
device must have the same n_sectors after fully configured to be
treated as the same device.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 6f266c8..d5939e6 100644 (file)
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -1919,7 +1919,6 @@ int ata_dev_configure(struct ata_device *dev)
                        snprintf(revbuf, 7, "ATA-%d",  ata_id_major_version(id));
 
                dev->n_sectors = ata_id_n_sectors(id);
-               dev->n_sectors_boot = dev->n_sectors;
 
                /* SCSI only uses 4-char revisions, dump full 8 chars from ATA */
                ata_id_c_string(dev->id, fwrevbuf, ATA_ID_FW_REV,
@@ -3632,7 +3631,6 @@ static int ata_dev_same_device(struct ata_device *dev, unsigned int new_class,
        const u16 *old_id = dev->id;
        unsigned char model[2][ATA_ID_PROD_LEN + 1];
        unsigned char serial[2][ATA_ID_SERNO_LEN + 1];
-       u64 new_n_sectors;
 
        if (dev->class != new_class) {
                ata_dev_printk(dev, KERN_INFO, "class mismatch %d != %d\n",
@@ -3644,7 +3642,6 @@ static int ata_dev_same_device(struct ata_device *dev, unsigned int new_class,
        ata_id_c_string(new_id, model[1], ATA_ID_PROD, sizeof(model[1]));
        ata_id_c_string(old_id, serial[0], ATA_ID_SERNO, sizeof(serial[0]));
        ata_id_c_string(new_id, serial[1], ATA_ID_SERNO, sizeof(serial[1]));
-       new_n_sectors = ata_id_n_sectors(new_id);
 
        if (strcmp(model[0], model[1])) {
                ata_dev_printk(dev, KERN_INFO, "model number mismatch "
@@ -3658,19 +3655,6 @@ static int ata_dev_same_device(struct ata_device *dev, unsigned int new_class,
                return 0;
        }
 
-       if (dev->class == ATA_DEV_ATA && dev->n_sectors != new_n_sectors) {
-               ata_dev_printk(dev, KERN_INFO, "n_sectors mismatch "
-                              "%llu != %llu\n",
-                              (unsigned long long)dev->n_sectors,
-                              (unsigned long long)new_n_sectors);
-               /* Are we the boot time size - if so we appear to be the
-                  same disk at this point and our HPA got reapplied */
-               if (ata_ignore_hpa && dev->n_sectors_boot == new_n_sectors 
-                   && ata_id_hpa_enabled(new_id))
-                       return 1;
-               return 0;
-       }
-
        return 1;
 }
 
@@ -3723,6 +3707,7 @@ int ata_dev_reread_id(struct ata_device *dev, unsigned int readid_flags)
  */
 int ata_dev_revalidate(struct ata_device *dev, unsigned int readid_flags)
 {
+       u64 n_sectors = dev->n_sectors;
        int rc;
 
        if (!ata_dev_enabled(dev))
@@ -3735,8 +3720,20 @@ int ata_dev_revalidate(struct ata_device *dev, unsigned int readid_flags)
 
        /* configure device according to the new ID */
        rc = ata_dev_configure(dev);
-       if (rc == 0)
-               return 0;
+       if (rc)
+               goto fail;
+
+       /* verify n_sectors hasn't changed */
+       if (dev->class == ATA_DEV_ATA && dev->n_sectors != n_sectors) {
+               ata_dev_printk(dev, KERN_INFO, "n_sectors mismatch "
+                              "%llu != %llu\n",
+                              (unsigned long long)n_sectors,
+                              (unsigned long long)dev->n_sectors);
+               rc = -ENODEV;
+               goto fail;
+       }
+
+       return 0;
 
  fail:
        ata_dev_printk(dev, KERN_ERR, "revalidation failed (errno=%d)\n", rc);

diff --git a/include/linux/libata.h b/include/linux/libata.h
index 27d9362..b38a0f9 100644 (file)
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -431,7 +431,6 @@ struct ata_device {
        struct scsi_device      *sdev;          /* attached SCSI device */
        /* n_sector is used as CLEAR_OFFSET, read comment above CLEAR_OFFSET */
        u64                     n_sectors;      /* size of device, if ATA */
-       u64                     n_sectors_boot; /* size of ATA device at startup */
        unsigned int            class;          /* ATA_DEV_xxx */
        u16                     id[ATA_ID_WORDS]; /* IDENTIFY xxx DEVICE data */
        u8                      pio_mode;