[7/9] btrfs: Add support for recovery for a RAID 5 btrfs profiles.
diff mbox series

Message ID 20180919184040.22540-8-kreijack@libero.it
State New
Headers show
Series
  • [1/9] btrfs: Add support for reading a filesystem with a RAID 5 or RAID 6 profile.
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Commit Message

Goffredo Baroncelli Sept. 19, 2018, 6:40 p.m. UTC
From: Goffredo Baroncelli <kreijack@inwind.it>

Add support for recovery for a RAID 5 btrfs profile. In addition
it is added some code as preparatory work for RAID 6 recovery code.

Signed-off-by: Goffredo Baroncelli <kreijack@inwind.it>
---
 grub-core/fs/btrfs.c | 169 +++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 164 insertions(+), 5 deletions(-)

Comments

Daniel Kiper Sept. 25, 2018, 7:10 p.m. UTC | #1
On Wed, Sep 19, 2018 at 08:40:38PM +0200, Goffredo Baroncelli wrote:
> From: Goffredo Baroncelli <kreijack@inwind.it>
>
> Add support for recovery for a RAID 5 btrfs profile. In addition
> it is added some code as preparatory work for RAID 6 recovery code.
>
> Signed-off-by: Goffredo Baroncelli <kreijack@inwind.it>
> ---
>  grub-core/fs/btrfs.c | 169 +++++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 164 insertions(+), 5 deletions(-)
>
> diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c
> index 5c1ebae77..55a7eeffc 100644
> --- a/grub-core/fs/btrfs.c
> +++ b/grub-core/fs/btrfs.c
> @@ -29,6 +29,7 @@
>  #include <minilzo.h>
>  #include <grub/i18n.h>
>  #include <grub/btrfs.h>
> +#include <grub/crypto.h>
>
>  GRUB_MOD_LICENSE ("GPLv3+");
>
> @@ -665,6 +666,148 @@ btrfs_read_from_chunk (struct grub_btrfs_data *data,
>      return err;
>  }
>
> +struct raid56_buffer {
> +  void *buf;
> +  int  data_is_valid;
> +};
> +
> +static void
> +rebuild_raid5 (char *dest, struct raid56_buffer *buffers,
> +	       grub_uint64_t nstripes, grub_uint64_t csize)
> +{
> +  grub_uint64_t i;
> +  int first;
> +
> +  i = 0;
> +  while (buffers[i].data_is_valid && i < nstripes)
> +    ++i;

for (i = 0; buffers[i].data_is_valid && i < nstripes; i++);

> +  if (i == nstripes)
> +    {
> +      grub_dprintf ("btrfs", "called rebuild_raid5(), but all disks are OK\n");
> +      return;
> +    }
> +
> +  grub_dprintf ("btrfs", "rebuilding RAID 5 stripe #%" PRIuGRUB_UINT64_T "\n",
> +	        i);

One line here please.

> +  for (i = 0, first = 1; i < nstripes; i++)
> +    {
> +      if (!buffers[i].data_is_valid)
> +	continue;
> +
> +      if (first) {
> +	grub_memcpy(dest, buffers[i].buf, csize);
> +	first = 0;
> +      } else
> +	grub_crypto_xor (dest, dest, buffers[i].buf, csize);
> +
> +    }

Hmmm... I think that this function can be simpler. You can drop first
while/for and "if (i == nstripes)". Then here:

if (first) {
  grub_dprintf ("btrfs", "called rebuild_raid5(), but all disks are OK\n");

Am I right?

> +}
> +
> +static grub_err_t
> +raid56_read_retry (struct grub_btrfs_data *data,
> +		   struct grub_btrfs_chunk_item *chunk,
> +		   grub_uint64_t stripe_offset,
> +		   grub_uint64_t csize, void *buf)
> +{
> +  struct raid56_buffer *buffers;
> +  grub_uint64_t nstripes = grub_le_to_cpu16 (chunk->nstripes);
> +  grub_uint64_t chunk_type = grub_le_to_cpu64 (chunk->type);
> +  grub_err_t ret = GRUB_ERR_NONE;

s/GRUB_ERR_NONE/GRUB_ERR_OUT_OF_MEMORY/ and then you can drop at
least two relevant assigments and some curly brackets. Of course
before cleanup label you have to add ret = GRUB_ERR_NONE.

> +  grub_uint64_t i, failed_devices;
> +
> +  buffers = grub_zalloc (sizeof(*buffers) * nstripes);
> +  if (!buffers)
> +    {
> +      ret = GRUB_ERR_OUT_OF_MEMORY;
> +      goto cleanup;
> +    }
> +
> +  for (i = 0; i < nstripes; i++)
> +    {
> +      buffers[i].buf = grub_zalloc (csize);
> +      if (!buffers[i].buf)
> +	{
> +	  ret = GRUB_ERR_OUT_OF_MEMORY;
> +	  goto cleanup;
> +	}
> +    }
> +
> +  for (failed_devices = 0, i = 0; i < nstripes; i++)
> +    {
> +      struct grub_btrfs_chunk_stripe *stripe;
> +      grub_disk_addr_t paddr;
> +      grub_device_t dev;
> +      grub_err_t err2;

s/err2/err/?

> +
> +      stripe = (struct grub_btrfs_chunk_stripe *) (chunk + 1);
> +      stripe += i;

Why not stripe = ((struct grub_btrfs_chunk_stripe *) (chunk + 1)) + i;?

Daniel
Goffredo Baroncelli Sept. 26, 2018, 7:55 p.m. UTC | #2
On 25/09/2018 21.10, Daniel Kiper wrote:
> On Wed, Sep 19, 2018 at 08:40:38PM +0200, Goffredo Baroncelli wrote:
>> From: Goffredo Baroncelli <kreijack@inwind.it>
>>
>> Add support for recovery for a RAID 5 btrfs profile. In addition
>> it is added some code as preparatory work for RAID 6 recovery code.
>>
>> Signed-off-by: Goffredo Baroncelli <kreijack@inwind.it>
>> ---
>>  grub-core/fs/btrfs.c | 169 +++++++++++++++++++++++++++++++++++++++++--
>>  1 file changed, 164 insertions(+), 5 deletions(-)
>>
>> diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c
>> index 5c1ebae77..55a7eeffc 100644
>> --- a/grub-core/fs/btrfs.c
>> +++ b/grub-core/fs/btrfs.c
>> @@ -29,6 +29,7 @@
>>  #include <minilzo.h>
>>  #include <grub/i18n.h>
>>  #include <grub/btrfs.h>
>> +#include <grub/crypto.h>
>>
>>  GRUB_MOD_LICENSE ("GPLv3+");
>>
>> @@ -665,6 +666,148 @@ btrfs_read_from_chunk (struct grub_btrfs_data *data,
>>      return err;
>>  }
>>
>> +struct raid56_buffer {
>> +  void *buf;
>> +  int  data_is_valid;
>> +};
>> +
>> +static void
>> +rebuild_raid5 (char *dest, struct raid56_buffer *buffers,
>> +	       grub_uint64_t nstripes, grub_uint64_t csize)
>> +{
>> +  grub_uint64_t i;
>> +  int first;
>> +
>> +  i = 0;
>> +  while (buffers[i].data_is_valid && i < nstripes)
>> +    ++i;
> 
> for (i = 0; buffers[i].data_is_valid && i < nstripes; i++);
> 
>> +  if (i == nstripes)
>> +    {
>> +      grub_dprintf ("btrfs", "called rebuild_raid5(), but all disks are OK\n");
>> +      return;
>> +    }
>> +
>> +  grub_dprintf ("btrfs", "rebuilding RAID 5 stripe #%" PRIuGRUB_UINT64_T "\n",
>> +	        i);
> 
> One line here please.
> 
>> +  for (i = 0, first = 1; i < nstripes; i++)
>> +    {
>> +      if (!buffers[i].data_is_valid)
>> +	continue;
>> +
>> +      if (first) {
>> +	grub_memcpy(dest, buffers[i].buf, csize);
>> +	first = 0;
>> +      } else
>> +	grub_crypto_xor (dest, dest, buffers[i].buf, csize);
>> +
>> +    }
> 
> Hmmm... I think that this function can be simpler. You can drop first
> while/for and "if (i == nstripes)". Then here:
> 
> if (first) {
>   grub_dprintf ("btrfs", "called rebuild_raid5(), but all disks are OK\n");
> 
> Am I right?

Ehm.. no. The "if" is an internal check to avoid BUG. rebuild_raid5() should be called only if some disk is missed.
To perform this control, the code checks if all buffers are valid. Otherwise there is an internal BUG.

Checking "first" is a completely different test.

>> +}
>> +
>> +static grub_err_t
>> +raid56_read_retry (struct grub_btrfs_data *data,
>> +		   struct grub_btrfs_chunk_item *chunk,
>> +		   grub_uint64_t stripe_offset,
>> +		   grub_uint64_t csize, void *buf)
>> +{
>> +  struct raid56_buffer *buffers;
>> +  grub_uint64_t nstripes = grub_le_to_cpu16 (chunk->nstripes);
>> +  grub_uint64_t chunk_type = grub_le_to_cpu64 (chunk->type);
>> +  grub_err_t ret = GRUB_ERR_NONE;
> 
> s/GRUB_ERR_NONE/GRUB_ERR_OUT_OF_MEMORY/ and then you can drop at
> least two relevant assigments and some curly brackets. Of course
> before cleanup label you have to add ret = GRUB_ERR_NONE.
> 
>> +  grub_uint64_t i, failed_devices;
>> +
>> +  buffers = grub_zalloc (sizeof(*buffers) * nstripes);
>> +  if (!buffers)
>> +    {
>> +      ret = GRUB_ERR_OUT_OF_MEMORY;
>> +      goto cleanup;
>> +    }
>> +
>> +  for (i = 0; i < nstripes; i++)
>> +    {
>> +      buffers[i].buf = grub_zalloc (csize);
>> +      if (!buffers[i].buf)
>> +	{
>> +	  ret = GRUB_ERR_OUT_OF_MEMORY;
>> +	  goto cleanup;
>> +	}
>> +    }
>> +
>> +  for (failed_devices = 0, i = 0; i < nstripes; i++)
>> +    {
>> +      struct grub_btrfs_chunk_stripe *stripe;
>> +      grub_disk_addr_t paddr;
>> +      grub_device_t dev;
>> +      grub_err_t err2;
> 
> s/err2/err/?

Ok

> 
>> +
>> +      stripe = (struct grub_btrfs_chunk_stripe *) (chunk + 1);
>> +      stripe += i;
> 
> Why not stripe = ((struct grub_btrfs_chunk_stripe *) (chunk + 1)) + i;?

Make sense
> 
> Daniel
>
Daniel Kiper Sept. 27, 2018, 4:18 p.m. UTC | #3
On Wed, Sep 26, 2018 at 09:55:57PM +0200, Goffredo Baroncelli wrote:
> On 25/09/2018 21.10, Daniel Kiper wrote:
> > On Wed, Sep 19, 2018 at 08:40:38PM +0200, Goffredo Baroncelli wrote:
> >> From: Goffredo Baroncelli <kreijack@inwind.it>
> >>
> >> Add support for recovery for a RAID 5 btrfs profile. In addition
> >> it is added some code as preparatory work for RAID 6 recovery code.
> >>
> >> Signed-off-by: Goffredo Baroncelli <kreijack@inwind.it>
> >> ---
> >>  grub-core/fs/btrfs.c | 169 +++++++++++++++++++++++++++++++++++++++++--
> >>  1 file changed, 164 insertions(+), 5 deletions(-)
> >>
> >> diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c
> >> index 5c1ebae77..55a7eeffc 100644
> >> --- a/grub-core/fs/btrfs.c
> >> +++ b/grub-core/fs/btrfs.c
> >> @@ -29,6 +29,7 @@
> >>  #include <minilzo.h>
> >>  #include <grub/i18n.h>
> >>  #include <grub/btrfs.h>
> >> +#include <grub/crypto.h>
> >>
> >>  GRUB_MOD_LICENSE ("GPLv3+");
> >>
> >> @@ -665,6 +666,148 @@ btrfs_read_from_chunk (struct grub_btrfs_data *data,
> >>      return err;
> >>  }
> >>
> >> +struct raid56_buffer {
> >> +  void *buf;
> >> +  int  data_is_valid;
> >> +};
> >> +
> >> +static void
> >> +rebuild_raid5 (char *dest, struct raid56_buffer *buffers,
> >> +	       grub_uint64_t nstripes, grub_uint64_t csize)
> >> +{
> >> +  grub_uint64_t i;
> >> +  int first;
> >> +
> >> +  i = 0;
> >> +  while (buffers[i].data_is_valid && i < nstripes)
> >> +    ++i;
> >
> > for (i = 0; buffers[i].data_is_valid && i < nstripes; i++);
> >
> >> +  if (i == nstripes)
> >> +    {
> >> +      grub_dprintf ("btrfs", "called rebuild_raid5(), but all disks are OK\n");
> >> +      return;
> >> +    }
> >> +
> >> +  grub_dprintf ("btrfs", "rebuilding RAID 5 stripe #%" PRIuGRUB_UINT64_T "\n",
> >> +	        i);
> >
> > One line here please.
> >
> >> +  for (i = 0, first = 1; i < nstripes; i++)
> >> +    {
> >> +      if (!buffers[i].data_is_valid)
> >> +	continue;
> >> +
> >> +      if (first) {
> >> +	grub_memcpy(dest, buffers[i].buf, csize);
> >> +	first = 0;
> >> +      } else
> >> +	grub_crypto_xor (dest, dest, buffers[i].buf, csize);
> >> +
> >> +    }
> >
> > Hmmm... I think that this function can be simpler. You can drop first
> > while/for and "if (i == nstripes)". Then here:
> >
> > if (first) {
> >   grub_dprintf ("btrfs", "called rebuild_raid5(), but all disks are OK\n");
> >
> > Am I right?
>
> Ehm.. no. The "if" is an internal check to avoid BUG. rebuild_raid5() should be called only if some disk is missed.
> To perform this control, the code checks if all buffers are valid. Otherwise there is an internal BUG.

Something is wrong here. I think that the code checks if it is an invalid
buffer. If there is not then GRUB complains. Right? However, it looks
that I misread the code and made a mistake here. So, please ignore
this change. Though please change while() with for() at the beginning.

Daniel

Patch
diff mbox series

diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c
index 5c1ebae77..55a7eeffc 100644
--- a/grub-core/fs/btrfs.c
+++ b/grub-core/fs/btrfs.c
@@ -29,6 +29,7 @@ 
 #include <minilzo.h>
 #include <grub/i18n.h>
 #include <grub/btrfs.h>
+#include <grub/crypto.h>
 
 GRUB_MOD_LICENSE ("GPLv3+");
 
@@ -665,6 +666,148 @@  btrfs_read_from_chunk (struct grub_btrfs_data *data,
     return err;
 }
 
+struct raid56_buffer {
+  void *buf;
+  int  data_is_valid;
+};
+
+static void
+rebuild_raid5 (char *dest, struct raid56_buffer *buffers,
+	       grub_uint64_t nstripes, grub_uint64_t csize)
+{
+  grub_uint64_t i;
+  int first;
+
+  i = 0;
+  while (buffers[i].data_is_valid && i < nstripes)
+    ++i;
+
+  if (i == nstripes)
+    {
+      grub_dprintf ("btrfs", "called rebuild_raid5(), but all disks are OK\n");
+      return;
+    }
+
+  grub_dprintf ("btrfs", "rebuilding RAID 5 stripe #%" PRIuGRUB_UINT64_T "\n",
+	        i);
+
+  for (i = 0, first = 1; i < nstripes; i++)
+    {
+      if (!buffers[i].data_is_valid)
+	continue;
+
+      if (first) {
+	grub_memcpy(dest, buffers[i].buf, csize);
+	first = 0;
+      } else
+	grub_crypto_xor (dest, dest, buffers[i].buf, csize);
+
+    }
+}
+
+static grub_err_t
+raid56_read_retry (struct grub_btrfs_data *data,
+		   struct grub_btrfs_chunk_item *chunk,
+		   grub_uint64_t stripe_offset,
+		   grub_uint64_t csize, void *buf)
+{
+  struct raid56_buffer *buffers;
+  grub_uint64_t nstripes = grub_le_to_cpu16 (chunk->nstripes);
+  grub_uint64_t chunk_type = grub_le_to_cpu64 (chunk->type);
+  grub_err_t ret = GRUB_ERR_NONE;
+  grub_uint64_t i, failed_devices;
+
+  buffers = grub_zalloc (sizeof(*buffers) * nstripes);
+  if (!buffers)
+    {
+      ret = GRUB_ERR_OUT_OF_MEMORY;
+      goto cleanup;
+    }
+
+  for (i = 0; i < nstripes; i++)
+    {
+      buffers[i].buf = grub_zalloc (csize);
+      if (!buffers[i].buf)
+	{
+	  ret = GRUB_ERR_OUT_OF_MEMORY;
+	  goto cleanup;
+	}
+    }
+
+  for (failed_devices = 0, i = 0; i < nstripes; i++)
+    {
+      struct grub_btrfs_chunk_stripe *stripe;
+      grub_disk_addr_t paddr;
+      grub_device_t dev;
+      grub_err_t err2;
+
+      stripe = (struct grub_btrfs_chunk_stripe *) (chunk + 1);
+      stripe += i;
+
+      paddr = grub_le_to_cpu64 (stripe->offset) + stripe_offset;
+      grub_dprintf ("btrfs", "reading paddr %" PRIxGRUB_UINT64_T
+                    " from stripe ID %" PRIxGRUB_UINT64_T "\n", paddr,
+                    stripe->device_id);
+
+      dev = find_device (data, stripe->device_id);
+      if (!dev)
+	{
+	  buffers[i].data_is_valid = 0;
+	  grub_dprintf ("btrfs", "stripe %" PRIuGRUB_UINT64_T " FAILED (dev ID %"
+			PRIxGRUB_UINT64_T ")\n", i, stripe->device_id);
+	  failed_devices++;
+	  continue;
+	}
+
+      err2 = grub_disk_read (dev->disk, paddr >> GRUB_DISK_SECTOR_BITS,
+			     paddr & (GRUB_DISK_SECTOR_SIZE - 1),
+			     csize, buffers[i].buf);
+      if (err2 == GRUB_ERR_NONE)
+	{
+	  buffers[i].data_is_valid = 1;
+	  grub_dprintf ("btrfs", "stripe %" PRIuGRUB_UINT64_T " Ok (dev ID %"
+			PRIxGRUB_UINT64_T ")\n", i, stripe->device_id);
+	}
+      else
+	{
+	  buffers[i].data_is_valid = 0;
+	  grub_dprintf ("btrfs", "stripe %" PRIuGRUB_UINT64_T
+			" FAILED (dev ID %" PRIxGRUB_UINT64_T ")\n", i,
+			stripe->device_id);
+	  failed_devices++;
+	}
+    }
+
+  if (failed_devices > 1 && (chunk_type & GRUB_BTRFS_CHUNK_TYPE_RAID5))
+    {
+      grub_dprintf ("btrfs",
+		    "not enough disks for RAID 5: total %" PRIuGRUB_UINT64_T
+		    ", missing %" PRIuGRUB_UINT64_T "\n",
+		    nstripes, failed_devices);
+      ret = GRUB_ERR_READ_ERROR;
+      goto cleanup;
+    }
+  else
+    grub_dprintf ("btrfs",
+		  "enough disks for RAID 5 rebuilding: total %"
+		  PRIuGRUB_UINT64_T ", missing %" PRIuGRUB_UINT64_T "\n",
+		  nstripes, failed_devices);
+
+  /* if these are enough, try to rebuild the data */
+  if (chunk_type & GRUB_BTRFS_CHUNK_TYPE_RAID5)
+    rebuild_raid5 (buf, buffers, nstripes, csize);
+  else
+    grub_dprintf ("btrfs", "called rebuild_raid6(), NOT IMPLEMENTED\n");
+
+ cleanup:
+  if (buffers)
+    for (i = 0; i < nstripes; i++)
+	grub_free(buffers[i].buf);
+  grub_free(buffers);
+
+  return ret;
+}
+
 static grub_err_t
 grub_btrfs_read_logical (struct grub_btrfs_data *data, grub_disk_addr_t addr,
 			 void *buf, grub_size_t size, int recursion_depth)
@@ -742,6 +885,10 @@  grub_btrfs_read_logical (struct grub_btrfs_data *data, grub_disk_addr_t addr,
 	grub_uint16_t nstripes;
 	unsigned redundancy = 1;
 	unsigned i, j;
+	int is_raid56;
+
+	is_raid56 = !!(grub_le_to_cpu64 (chunk->type) &
+		       GRUB_BTRFS_CHUNK_TYPE_RAID5);
 
 	if (grub_le_to_cpu64 (chunk->size) <= off)
 	  {
@@ -914,17 +1061,29 @@  grub_btrfs_read_logical (struct grub_btrfs_data *data, grub_disk_addr_t addr,
 	    grub_dprintf ("btrfs", "reading laddr 0x%" PRIxGRUB_UINT64_T "\n",
 			  addr);
 
-	    for (i = 0; i < redundancy; i++)
+	    if (!is_raid56)
+	      for (i = 0; i < redundancy; i++)
+		{
+		  err = btrfs_read_from_chunk (data, chunk, stripen,
+					       stripe_offset,
+					       i,     /* redundancy */
+					       csize, buf);
+		  if (!err)
+		    break;
+		  grub_errno = GRUB_ERR_NONE;
+		}
+	    else
 	      {
 		err = btrfs_read_from_chunk (data, chunk, stripen,
 					     stripe_offset,
-					     i,     /* redundancy */
+					     0,     /* no mirror */
 					     csize, buf);
-		if (!err)
-		  break;
 		grub_errno = GRUB_ERR_NONE;
+		if (err != GRUB_ERR_NONE)
+		  err = raid56_read_retry (data, chunk, stripe_offset,
+					   csize, buf);
 	      }
-	    if (i != redundancy)
+	    if (err == GRUB_ERR_NONE)
 	      break;
 	  }
 	if (err)