ocfs2: Make cached block reads the common case.

ocfs2_read_blocks() currently requires the CACHED flag for cached I/O.
However, that's the common case.  Let's flip it around and provide an
IGNORE_CACHE flag for the special users.  This has the added benefit of
cleaning up the code some (ignore_cache takes on its special meaning
earlier in the loop).

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

7 files changed, 24 insertions, 17 deletions

diff --git a/fs/ocfs2/buffer_head_io.c b/fs/ocfs2/buffer_head_io.c
index 718dbe5607c..7e947c67246 100644
--- a/fs/ocfs2/buffer_head_io.c
+++ b/fs/ocfs2/buffer_head_io.c
@@ -181,7 +181,8 @@ int ocfs2_read_blocks(struct inode *inode, u64 block, int nr,
                    inode, (unsigned long long)block, nr, flags);
 
         BUG_ON(!inode);
-        BUG_ON((flags & OCFS2_BH_READAHEAD) && !(flags & OCFS2_BH_CACHED));
+        BUG_ON((flags & OCFS2_BH_READAHEAD) &&
+               (flags & OCFS2_BH_IGNORE_CACHE));
 
         if (bhs == NULL) {
                 status = -EINVAL;
@@ -214,7 +215,7 @@ int ocfs2_read_blocks(struct inode *inode, u64 block, int nr,
                         }
                 }
                 bh = bhs[i];
-                ignore_cache = 0;
+                ignore_cache = (flags & OCFS2_BH_IGNORE_CACHE);
 
                 /* There are three read-ahead cases here which we need to
                  * be concerned with. All three assume a buffer has
@@ -240,26 +241,27 @@ int ocfs2_read_blocks(struct inode *inode, u64 block, int nr,
                  *    before our is-it-in-flight check.
                  */
 
-                if (flags & OCFS2_BH_CACHED &&
-                    !ocfs2_buffer_uptodate(inode, bh)) {
+                if (!ignore_cache && !ocfs2_buffer_uptodate(inode, bh)) {
                         mlog(ML_UPTODATE,
                              "bh (%llu), inode %llu not uptodate\n",
                              (unsigned long long)bh->b_blocknr,
                              (unsigned long long)OCFS2_I(inode)->ip_blkno);
+                        /* We're using ignore_cache here to say
+                         * "go to disk" */
                         ignore_cache = 1;
                 }
 
                 /* XXX: Can we ever get this and *not* have the cached
                  * flag set? */
                 if (buffer_jbd(bh)) {
-                        if (!(flags & OCFS2_BH_CACHED) || ignore_cache)
+                        if (ignore_cache)
                                 mlog(ML_BH_IO, "trying to sync read a jbd "
                                                "managed bh (blocknr = %llu)\n",
                                      (unsigned long long)bh->b_blocknr);
                         continue;
                 }
 
-                if (!(flags & OCFS2_BH_CACHED) || ignore_cache) {
+                if (ignore_cache) {
                         if (buffer_dirty(bh)) {
                                 /* This should probably be a BUG, or
                                  * at least return an error. */
@@ -294,7 +296,7 @@ int ocfs2_read_blocks(struct inode *inode, u64 block, int nr,
                          * previously read-ahead buffer may have
                          * completed I/O while we were waiting for the
                          * buffer lock. */
-                        if ((flags & OCFS2_BH_CACHED)
+                        if (!(flags & OCFS2_BH_IGNORE_CACHE)
                             && !(flags & OCFS2_BH_READAHEAD)
                             && ocfs2_buffer_uptodate(inode, bh)) {
                                 unlock_buffer(bh);
@@ -344,7 +346,8 @@ int ocfs2_read_blocks(struct inode *inode, u64 block, int nr,
 
         mlog(ML_BH_IO, "block=(%llu), nr=(%d), cached=%s, flags=0x%x\n", 
              (unsigned long long)block, nr,
-             (!(flags & OCFS2_BH_CACHED) || ignore_cache) ? "no" : "yes", flags);
+             ((flags & OCFS2_BH_IGNORE_CACHE) || ignore_cache) ? "no" : "yes",
+             flags);
 
 bail:
 
diff --git a/fs/ocfs2/buffer_head_io.h b/fs/ocfs2/buffer_head_io.h
index a2ef9e5f8bf..75e1dcb1ade 100644
--- a/fs/ocfs2/buffer_head_io.h
+++ b/fs/ocfs2/buffer_head_io.h
@@ -49,7 +49,7 @@ int ocfs2_read_blocks_sync(struct ocfs2_super *osb, u64 block,
 int ocfs2_write_super_or_backup(struct ocfs2_super *osb,
                                 struct buffer_head *bh);
 
-#define OCFS2_BH_CACHED            1
+#define OCFS2_BH_IGNORE_CACHE      1
 #define OCFS2_BH_READAHEAD         8
 
 static inline int ocfs2_read_block(struct inode *inode, u64 off,
@@ -63,7 +63,7 @@ static inline int ocfs2_read_block(struct inode *inode, u64 off,
                 goto bail;
         }
 
-        status = ocfs2_read_blocks(inode, off, 1, bh, OCFS2_BH_CACHED);
+        status = ocfs2_read_blocks(inode, off, 1, bh, 0);
 
 bail:
         return status;
diff --git a/fs/ocfs2/dir.c b/fs/ocfs2/dir.c
index 60be3ba1f5d..026e6eb8518 100644
--- a/fs/ocfs2/dir.c
+++ b/fs/ocfs2/dir.c
@@ -88,7 +88,7 @@ static struct buffer_head *ocfs2_bread(struct inode *inode,
         struct buffer_head *bh = NULL;
         int tmperr;
         u64 p_blkno;
-        int readflags = OCFS2_BH_CACHED;
+        int readflags = 0;
 
         if (reada)
                 readflags |= OCFS2_BH_READAHEAD;
diff --git a/fs/ocfs2/inode.c b/fs/ocfs2/inode.c
index 8381c26b21a..4903688f72a 100644
--- a/fs/ocfs2/inode.c
+++ b/fs/ocfs2/inode.c
@@ -461,7 +461,8 @@ static int ocfs2_read_locked_inode(struct inode *inode,
         }
 
         if (can_lock)
-                status = ocfs2_read_blocks(inode, args->fi_blkno, 1, &bh, 0);
+                status = ocfs2_read_blocks(inode, args->fi_blkno, 1, &bh,
+                                           OCFS2_BH_IGNORE_CACHE);
         else
                 status = ocfs2_read_blocks_sync(osb, args->fi_blkno, 1, &bh);
         if (status < 0) {
diff --git a/fs/ocfs2/journal.c b/fs/ocfs2/journal.c
index d161fe5e3bd..81e40677eec 100644
--- a/fs/ocfs2/journal.c
+++ b/fs/ocfs2/journal.c
@@ -1134,7 +1134,8 @@ static int ocfs2_read_journal_inode(struct ocfs2_super *osb,
         }
         SET_INODE_JOURNAL(inode);
 
-        status = ocfs2_read_blocks(inode, OCFS2_I(inode)->ip_blkno, 1, bh, 0);
+        status = ocfs2_read_blocks(inode, OCFS2_I(inode)->ip_blkno, 1, bh,
+                                   OCFS2_BH_IGNORE_CACHE);
         if (status < 0) {
                 mlog_errno(status);
                 goto bail;
diff --git a/fs/ocfs2/localalloc.c b/fs/ocfs2/localalloc.c
index 3ea740d15fe..687b28713c3 100644
--- a/fs/ocfs2/localalloc.c
+++ b/fs/ocfs2/localalloc.c
@@ -249,7 +249,7 @@ int ocfs2_load_local_alloc(struct ocfs2_super *osb)
         }
 
         status = ocfs2_read_blocks(inode, OCFS2_I(inode)->ip_blkno, 1,
-                                   &alloc_bh, 0);
+                                   &alloc_bh, OCFS2_BH_IGNORE_CACHE);
         if (status < 0) {
                 mlog_errno(status);
                 goto bail;
@@ -460,7 +460,7 @@ int ocfs2_begin_local_alloc_recovery(struct ocfs2_super *osb,
         mutex_lock(&inode->i_mutex);
 
         status = ocfs2_read_blocks(inode, OCFS2_I(inode)->ip_blkno, 1,
-                                   &alloc_bh, 0);
+                                   &alloc_bh, OCFS2_BH_IGNORE_CACHE);
         if (status < 0) {
                 mlog_errno(status);
                 goto bail;
diff --git a/fs/ocfs2/slot_map.c b/fs/ocfs2/slot_map.c
index 357d3fe18c3..bdda2d8f850 100644
--- a/fs/ocfs2/slot_map.c
+++ b/fs/ocfs2/slot_map.c
@@ -150,7 +150,8 @@ int ocfs2_refresh_slot_info(struct ocfs2_super *osb)
          * be !NULL.  Thus, ocfs2_read_blocks() will ignore blocknr.  If
          * this is not true, the read of -1 (UINT64_MAX) will fail.
          */
-        ret = ocfs2_read_blocks(si->si_inode, -1, si->si_blocks, si->si_bh, 0);
+        ret = ocfs2_read_blocks(si->si_inode, -1, si->si_blocks, si->si_bh,
+                                OCFS2_BH_IGNORE_CACHE);
         if (ret == 0) {
                 spin_lock(&osb->osb_lock);
                 ocfs2_update_slot_info(si);
@@ -403,7 +404,8 @@ static int ocfs2_map_slot_buffers(struct ocfs2_super *osb,
                      (unsigned long long)blkno);
 
                 bh = NULL;  /* Acquire a fresh bh */
-                status = ocfs2_read_blocks(si->si_inode, blkno, 1, &bh, 0);
+                status = ocfs2_read_blocks(si->si_inode, blkno, 1, &bh,
+                                           OCFS2_BH_IGNORE_CACHE);
                 if (status < 0) {
                         mlog_errno(status);
                         goto bail;