[PATCH] 64-bit jbd2 core

Here is the patch to JBD to handle 64 bit block numbers, originally from Zach
Brown.  This patch is useful only after adding support for 64-bit block
numbers in the filesystem.

Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: Zach Brown <zach.brown@oracle.com>
Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

5 files changed, 77 insertions, 22 deletions

diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index b1a4eafc1541..44d68a113c73 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -271,6 +271,14 @@ write_out_data:
         journal_do_submit_data(wbuf, bufs);
 }
 
+static inline void write_tag_block(int tag_bytes, journal_block_tag_t *tag,
+                                   sector_t block)
+{
+        tag->t_blocknr = cpu_to_be32(block & (u32)~0);
+        if (tag_bytes > JBD_TAG_SIZE32)
+                tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1);
+}
+
 /*
  * jbd2_journal_commit_transaction
  *
@@ -293,6 +301,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
         int first_tag = 0;
         int tag_flag;
         int i;
+        int tag_bytes = journal_tag_bytes(journal);
 
         /*
          * First job: lock down the current transaction and wait for
@@ -597,10 +606,10 @@ void jbd2_journal_commit_transaction(journal_t *journal)
                         tag_flag |= JBD2_FLAG_SAME_UUID;
 
                 tag = (journal_block_tag_t *) tagp;
-                tag->t_blocknr = cpu_to_be32(jh2bh(jh)->b_blocknr);
+                write_tag_block(tag_bytes, tag, jh2bh(jh)->b_blocknr);
                 tag->t_flags = cpu_to_be32(tag_flag);
-                tagp += sizeof(journal_block_tag_t);
-                space_left -= sizeof(journal_block_tag_t);
+                tagp += tag_bytes;
+                space_left -= tag_bytes;
 
                 if (first_tag) {
                         memcpy (tagp, journal->j_uuid, 16);
@@ -614,7 +623,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
 
                 if (bufs == journal->j_wbufsize ||
                     commit_transaction->t_buffers == NULL ||
-                    space_left < sizeof(journal_block_tag_t) + 16) {
+                    space_left < tag_bytes + 16) {
 
                         jbd_debug(4, "JBD: Submit %d IOs\n", bufs);
 
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 8d0f71e562fe..926ebcbf8a7a 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -1610,6 +1610,17 @@ int jbd2_journal_blocks_per_page(struct inode *inode)
 }
 
 /*
+ * helper functions to deal with 32 or 64bit block numbers.
+ */
+size_t journal_tag_bytes(journal_t *journal)
+{
+        if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_64BIT))
+                return JBD_TAG_SIZE64;
+        else
+                return JBD_TAG_SIZE32;
+}
+
+/*
  * Simple support for retrying memory allocations.  Introduced to help to
  * debug different VM deadlock avoidance strategies.
  */
diff --git a/fs/jbd2/recovery.c b/fs/jbd2/recovery.c
index b2012d112432..2486843adda0 100644
--- a/fs/jbd2/recovery.c
+++ b/fs/jbd2/recovery.c
@@ -178,19 +178,20 @@ static int jread(struct buffer_head **bhp, journal_t *journal,
  * Count the number of in-use tags in a journal descriptor block.
  */
 
-static int count_tags(struct buffer_head *bh, int size)
+static int count_tags(journal_t *journal, struct buffer_head *bh)
 {
         char *                  tagp;
         journal_block_tag_t *   tag;
-        int                     nr = 0;
+        int                     nr = 0, size = journal->j_blocksize;
+        int                     tag_bytes = journal_tag_bytes(journal);
 
         tagp = &bh->b_data[sizeof(journal_header_t)];
 
-        while ((tagp - bh->b_data + sizeof(journal_block_tag_t)) <= size) {
+        while ((tagp - bh->b_data + tag_bytes) <= size) {
                 tag = (journal_block_tag_t *) tagp;
 
                 nr++;
-                tagp += sizeof(journal_block_tag_t);
+                tagp += tag_bytes;
                 if (!(tag->t_flags & cpu_to_be32(JBD2_FLAG_SAME_UUID)))
                         tagp += 16;
 
@@ -307,6 +308,14 @@ int jbd2_journal_skip_recovery(journal_t *journal)
         return err;
 }
 
+static inline sector_t read_tag_block(int tag_bytes, journal_block_tag_t *tag)
+{
+        sector_t block = be32_to_cpu(tag->t_blocknr);
+        if (tag_bytes > JBD_TAG_SIZE32)
+                block |= (u64)be32_to_cpu(tag->t_blocknr_high) << 32;
+        return block;
+}
+
 static int do_one_pass(journal_t *journal,
                         struct recovery_info *info, enum passtype pass)
 {
@@ -318,11 +327,12 @@ static int do_one_pass(journal_t *journal,
         struct buffer_head *    bh;
         unsigned int            sequence;
         int                     blocktype;
+        int                     tag_bytes = journal_tag_bytes(journal);
 
         /* Precompute the maximum metadata descriptors in a descriptor block */
         int                     MAX_BLOCKS_PER_DESC;
         MAX_BLOCKS_PER_DESC = ((journal->j_blocksize-sizeof(journal_header_t))
-                               / sizeof(journal_block_tag_t));
+                               / tag_bytes);
 
         /*
          * First thing is to establish what we expect to find in the log
@@ -412,8 +422,7 @@ static int do_one_pass(journal_t *journal,
                          * in pass REPLAY; otherwise, just skip over the
                          * blocks it describes. */
                         if (pass != PASS_REPLAY) {
-                                next_log_block +=
-                                        count_tags(bh, journal->j_blocksize);
+                                next_log_block += count_tags(journal, bh);
                                 wrap(journal, next_log_block);
                                 brelse(bh);
                                 continue;
@@ -424,7 +433,7 @@ static int do_one_pass(journal_t *journal,
                          * getting done here! */
 
                         tagp = &bh->b_data[sizeof(journal_header_t)];
-                        while ((tagp - bh->b_data +sizeof(journal_block_tag_t))
+                        while ((tagp - bh->b_data + tag_bytes)
                                <= journal->j_blocksize) {
                                 unsigned long io_block;
 
@@ -446,7 +455,8 @@ static int do_one_pass(journal_t *journal,
                                         unsigned long blocknr;
 
                                         J_ASSERT(obh != NULL);
-                                        blocknr = be32_to_cpu(tag->t_blocknr);
+                                        blocknr = read_tag_block(tag_bytes,
+                                                                 tag);
 
                                         /* If the block has been
                                          * revoked, then we're all done
@@ -494,7 +504,7 @@ static int do_one_pass(journal_t *journal,
                                 }
 
                         skip_write:
-                                tagp += sizeof(journal_block_tag_t);
+                                tagp += tag_bytes;
                                 if (!(flags & JBD2_FLAG_SAME_UUID))
                                         tagp += 16;
 
@@ -572,17 +582,24 @@ static int scan_revoke_records(journal_t *journal, struct buffer_head *bh,
 {
         jbd2_journal_revoke_header_t *header;
         int offset, max;
+        int record_len = 4;
 
         header = (jbd2_journal_revoke_header_t *) bh->b_data;
         offset = sizeof(jbd2_journal_revoke_header_t);
         max = be32_to_cpu(header->r_count);
 
-        while (offset < max) {
+        if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_64BIT))
+                record_len = 8;
+
+        while (offset + record_len <= max) {
                 unsigned long blocknr;
                 int err;
 
-                blocknr = be32_to_cpu(* ((__be32 *) (bh->b_data+offset)));
-                offset += 4;
+                if (record_len == 4)
+                        blocknr = be32_to_cpu(* ((__be32 *) (bh->b_data+offset)));
+                else
+                        blocknr = be64_to_cpu(* ((__be64 *) (bh->b_data+offset)));
+                offset += record_len;
                 err = jbd2_journal_set_revoke(journal, blocknr, sequence);
                 if (err)
                         return err;
diff --git a/fs/jbd2/revoke.c b/fs/jbd2/revoke.c
index 5820a0c5ad26..8aac875bd301 100644
--- a/fs/jbd2/revoke.c
+++ b/fs/jbd2/revoke.c
@@ -584,9 +584,17 @@ static void write_one_revoke_record(journal_t *journal,
                 *descriptorp = descriptor;
         }
 
-        * ((__be32 *)(&jh2bh(descriptor)->b_data[offset])) =
-                cpu_to_be32(record->blocknr);
-        offset += 4;
+        if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_64BIT)) {
+                * ((__be64 *)(&jh2bh(descriptor)->b_data[offset])) =
+                        cpu_to_be64(record->blocknr);
+                offset += 8;
+
+        } else {
+                * ((__be32 *)(&jh2bh(descriptor)->b_data[offset])) =
+                        cpu_to_be32(record->blocknr);
+                offset += 4;
+        }
+
         *offsetp = offset;
 }
 
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index 3251f7abb57d..5e5aa64f1261 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -150,14 +150,21 @@ typedef struct journal_header_s
 
 
 /*
- * The block tag: used to describe a single buffer in the journal
+ * The block tag: used to describe a single buffer in the journal.
+ * t_blocknr_high is only used if INCOMPAT_64BIT is set, so this
+ * raw struct shouldn't be used for pointer math or sizeof() - use
+ * journal_tag_bytes(journal) instead to compute this.
  */
 typedef struct journal_block_tag_s
 {
         __be32          t_blocknr;      /* The on-disk block number */
         __be32          t_flags;        /* See below */
+        __be32          t_blocknr_high; /* most-significant high 32bits. */
 } journal_block_tag_t;
 
+#define JBD_TAG_SIZE32 (offsetof(journal_block_tag_t, t_blocknr_high))
+#define JBD_TAG_SIZE64 (sizeof(journal_block_tag_t))
+
 /*
  * The revoke descriptor: used on disk to describe a series of blocks to
  * be revoked from the log
@@ -235,11 +242,13 @@ typedef struct journal_superblock_s
          ((j)->j_superblock->s_feature_incompat & cpu_to_be32((mask))))
 
 #define JBD2_FEATURE_INCOMPAT_REVOKE    0x00000001
+#define JBD2_FEATURE_INCOMPAT_64BIT     0x00000002
 
 /* Features known to this kernel version: */
 #define JBD2_KNOWN_COMPAT_FEATURES      0
 #define JBD2_KNOWN_ROCOMPAT_FEATURES    0
-#define JBD2_KNOWN_INCOMPAT_FEATURES    JBD2_FEATURE_INCOMPAT_REVOKE
+#define JBD2_KNOWN_INCOMPAT_FEATURES    (JBD2_FEATURE_INCOMPAT_REVOKE | \
+                                         JBD2_FEATURE_INCOMPAT_64BIT)
 
 #ifdef __KERNEL__
 
@@ -1052,6 +1061,7 @@ static inline int tid_geq(tid_t x, tid_t y)
 }
 
 extern int jbd2_journal_blocks_per_page(struct inode *inode);
+extern size_t journal_tag_bytes(journal_t *journal);
 
 /*
  * Return the minimum number of blocks which must be free in the journal