[Ocfs2-devel] [PATCH 6/6] ocfs2: Make cached block reads the common case.
Joel Becker
joel.becker at oracle.com
Thu Oct 9 17:20:34 PDT 2008
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 at oracle.com>
---
fs/ocfs2/buffer_head_io.c | 19 +++++++++++--------
fs/ocfs2/buffer_head_io.h | 4 ++--
fs/ocfs2/dir.c | 2 +-
fs/ocfs2/inode.c | 3 ++-
fs/ocfs2/journal.c | 3 ++-
fs/ocfs2/localalloc.c | 4 ++--
fs/ocfs2/slot_map.c | 6 ++++--
7 files changed, 24 insertions(+), 17 deletions(-)
diff --git a/fs/ocfs2/buffer_head_io.c b/fs/ocfs2/buffer_head_io.c
index 718dbe5..7e947c6 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 a2ef9e5..75e1dcb 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 63f4839..40cd761 100644
--- a/fs/ocfs2/dir.c
+++ b/fs/ocfs2/dir.c
@@ -213,7 +213,7 @@ static struct buffer_head *ocfs2_bread(struct inode *inode, int block,
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 463c52d..886d77e 100644
--- a/fs/ocfs2/inode.c
+++ b/fs/ocfs2/inode.c
@@ -449,7 +449,8 @@ 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 ba646ef..ed7599d 100644
--- a/fs/ocfs2/journal.c
+++ b/fs/ocfs2/journal.c
@@ -1187,7 +1187,8 @@ 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 9ac0be9..3dbdcc9 100644
--- a/fs/ocfs2/localalloc.c
+++ b/fs/ocfs2/localalloc.c
@@ -140,7 +140,7 @@ 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;
@@ -346,7 +346,7 @@ 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 357d3fe..bdda2d8 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;
--
1.5.6.5
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