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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>
This commit is contained in:
Joel Becker 2008-10-09 17:20:34 -07:00 committed by Mark Fasheh
parent 5e0b3dec01
commit d4a8c93c82
7 changed files with 24 additions and 17 deletions
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19
fs/ocfs2/buffer_head_io.c
View File

@ -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:

4
fs/ocfs2/buffer_head_io.h
View File

@ -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;

2
fs/ocfs2/dir.c
View File

@ -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;

3
fs/ocfs2/inode.c
View File

@ -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) {

3
fs/ocfs2/journal.c
View File

@ -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;

4
fs/ocfs2/localalloc.c
View File

@ -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;

6
fs/ocfs2/slot_map.c
View File

@ -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;