[PATCH 37/37] xfs: make XBF_MAPPED the default behaviour

Dave Chinner
2012-04-23T05:59:52Z

From: Dave Chinner <dchinner@redhat.com>

Rather than specifying XBF_MAPPED for almost all buffers, introduce
XBF_UNMAPPED for the couple of users that use unmapped buffers.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
fs/xfs/xfs_buf.c | 28 +++++++++++++---------------
fs/xfs/xfs_buf.h | 4 ++--
fs/xfs/xfs_fsops.c | 10 +++++-----
fs/xfs/xfs_inode.c | 1 +
fs/xfs/xfs_log_recover.c | 4 ++--
fs/xfs/xfs_trans_buf.c | 6 ------
fs/xfs/xfs_vnodeops.c | 3 +--
7 files changed, 24 insertions(+), 32 deletions(-)

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index b2795ba..172d3cc 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -65,11 +65,11 @@ xfs_buf_is_vmapped(
/*
* Return true if the buffer is vmapped.
*
- * The XBF_MAPPED flag is set if the buffer should be mapped, but the
- * code is clever enough to know it doesn't have to map a single page,
- * so the check has to be both for XBF_MAPPED and bp->b_page_count > 1.
+ * b_addr is null if the buffer is not mapped, but the code is clever
+ * enough to know it doesn't have to map a single page, so the check has
+ * to be both for b_addr and bp->b_page_count > 1.
*/
- return (bp->b_flags & XBF_MAPPED) && bp->b_page_count > 1;
+ return bp->b_addr && bp->b_page_count > 1;
}

static inline int
@@ -181,7 +181,7 @@ xfs_buf_alloc(
* We don't want certain flags to appear in b_flags unless they are
* specifically set by later operations on the buffer.
*/
- flags &= ~(XBF_MAPPED | XBF_TRYLOCK | XBF_ASYNC | XBF_READ_AHEAD);
+ flags &= ~(XBF_UNMAPPED | XBF_TRYLOCK | XBF_ASYNC | XBF_READ_AHEAD);

atomic_set(&bp->b_hold, 1);
atomic_set(&bp->b_lru_ref, 1);
@@ -329,7 +329,7 @@ xfs_buf_allocate_memory(
bp->b_pages = bp->b_page_array;
bp->b_pages[0] = virt_to_page(bp->b_addr);
bp->b_page_count = 1;
- bp->b_flags |= XBF_MAPPED | _XBF_KMEM;
+ bp->b_flags |= _XBF_KMEM;
return 0;
}

@@ -399,8 +399,9 @@ _xfs_buf_map_pages(
if (bp->b_page_count == 1) {
/* A single page buffer is always mappable */
bp->b_addr = page_address(bp->b_pages[0]) + bp->b_offset;
- bp->b_flags |= XBF_MAPPED;
- } else if (flags & XBF_MAPPED) {
+ } else if (flags & XBF_UNMAPPED) {
+ bp->b_addr = NULL;
+ } else {
int retried = 0;

do {
@@ -414,7 +415,6 @@ _xfs_buf_map_pages(
if (!bp->b_addr)
return -ENOMEM;
bp->b_addr += bp->b_offset;
- bp->b_flags |= XBF_MAPPED;
}

return 0;
@@ -520,7 +520,7 @@ found:
*/
if (bp->b_flags & XBF_STALE) {
ASSERT((bp->b_flags & _XBF_DELWRI_Q) == 0);
- bp->b_flags &= XBF_MAPPED | _XBF_KMEM | _XBF_PAGES;
+ bp->b_flags &= _XBF_KMEM | _XBF_PAGES;
}

trace_xfs_buf_find(bp, flags, _RET_IP_);
@@ -575,7 +575,7 @@ xfs_buf_get(
bp->b_io_length = bp->b_length;

found:
- if (!(bp->b_flags & XBF_MAPPED)) {
+ if (!bp->b_addr) {
error = _xfs_buf_map_pages(bp, flags);
if (unlikely(error)) {
xfs_warn(target->bt_mount,
@@ -707,7 +707,6 @@ xfs_buf_set_empty(
bp->b_length = numblks;
bp->b_io_length = numblks;
bp->b_bn = XFS_BUF_DADDR_NULL;
- bp->b_flags &= ~XBF_MAPPED;
}

static inline struct page *
@@ -759,7 +758,6 @@ xfs_buf_associate_memory(

bp->b_io_length = BTOBB(len);
bp->b_length = BTOBB(buflen);
- bp->b_flags |= XBF_MAPPED;

return 0;
}
@@ -790,7 +788,7 @@ xfs_buf_get_uncached(
}
bp->b_flags |= _XBF_PAGES;

- error = _xfs_buf_map_pages(bp, XBF_MAPPED);
+ error = _xfs_buf_map_pages(bp, 0);
if (unlikely(error)) {
xfs_warn(target->bt_mount,
"%s: failed to map pages\n", __func__);
@@ -1287,7 +1285,7 @@ xfs_buf_offset(
{
struct page *page;

- if (bp->b_flags & XBF_MAPPED)
+ if (bp->b_addr)
return bp->b_addr + offset;

offset += bp->b_offset;
diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h
index 846dee3..7f1d139 100644
--- a/fs/xfs/xfs_buf.h
+++ b/fs/xfs/xfs_buf.h
@@ -41,7 +41,6 @@ typedef enum {
#define XBF_READ (1 << 0) /* buffer intended for reading from device */
#define XBF_WRITE (1 << 1) /* buffer intended for writing to device */
#define XBF_READ_AHEAD (1 << 2) /* asynchronous read-ahead */
-#define XBF_MAPPED (1 << 3) /* buffer mapped (b_addr valid) */
#define XBF_ASYNC (1 << 4) /* initiator will not wait for completion */
#define XBF_DONE (1 << 5) /* all pages in the buffer uptodate */
#define XBF_STALE (1 << 6) /* buffer has been staled, do not find it */
@@ -53,6 +52,7 @@ typedef enum {

/* flags used only as arguments to access routines */
#define XBF_TRYLOCK (1 << 16)/* lock requested, but do not wait */
+#define XBF_UNMAPPED (1 << 17)/* do not map the buffer */

/* flags used only internally */
#define _XBF_PAGES (1 << 20)/* backed by refcounted pages */
@@ -65,7 +65,6 @@ typedef unsigned int xfs_buf_flags_t;
{ XBF_READ, "READ" }, \
{ XBF_WRITE, "WRITE" }, \
{ XBF_READ_AHEAD, "READ_AHEAD" }, \
- { XBF_MAPPED, "MAPPED" }, \
{ XBF_ASYNC, "ASYNC" }, \
{ XBF_DONE, "DONE" }, \
{ XBF_STALE, "STALE" }, \
@@ -73,6 +72,7 @@ typedef unsigned int xfs_buf_flags_t;
{ XBF_FUA, "FUA" }, \
{ XBF_FLUSH, "FLUSH" }, \
{ XBF_TRYLOCK, "TRYLOCK" }, /* should never be set */\
+ { XBF_UNMAPPED, "UNMAPPED" }, /* ditto */\
{ _XBF_PAGES, "PAGES" }, \
{ _XBF_KMEM, "KMEM" }, \
{ _XBF_DELWRI_Q, "DELWRI_Q" }
diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
index 75593d9..c25b094 100644
--- a/fs/xfs/xfs_fsops.c
+++ b/fs/xfs/xfs_fsops.c
@@ -190,7 +190,7 @@ xfs_growfs_data_private(
*/
bp = xfs_buf_get(mp->m_ddev_targp,
XFS_AG_DADDR(mp, agno, XFS_AGF_DADDR(mp)),
- XFS_FSS_TO_BB(mp, 1), XBF_MAPPED);
+ XFS_FSS_TO_BB(mp, 1), 0);
if (!bp) {
error = ENOMEM;
goto error0;
@@ -227,7 +227,7 @@ xfs_growfs_data_private(
*/
bp = xfs_buf_get(mp->m_ddev_targp,
XFS_AG_DADDR(mp, agno, XFS_AGI_DADDR(mp)),
- XFS_FSS_TO_BB(mp, 1), XBF_MAPPED);
+ XFS_FSS_TO_BB(mp, 1), 0);
if (!bp) {
error = ENOMEM;
goto error0;
@@ -256,7 +256,7 @@ xfs_growfs_data_private(
*/
bp = xfs_buf_get(mp->m_ddev_targp,
XFS_AGB_TO_DADDR(mp, agno, XFS_BNO_BLOCK(mp)),
- BTOBB(mp->m_sb.sb_blocksize), XBF_MAPPED);
+ BTOBB(mp->m_sb.sb_blocksize), 0);
if (!bp) {
error = ENOMEM;
goto error0;
@@ -282,7 +282,7 @@ xfs_growfs_data_private(
*/
bp = xfs_buf_get(mp->m_ddev_targp,
XFS_AGB_TO_DADDR(mp, agno, XFS_CNT_BLOCK(mp)),
- BTOBB(mp->m_sb.sb_blocksize), XBF_MAPPED);
+ BTOBB(mp->m_sb.sb_blocksize), 0);
if (!bp) {
error = ENOMEM;
goto error0;
@@ -309,7 +309,7 @@ xfs_growfs_data_private(
*/
bp = xfs_buf_get(mp->m_ddev_targp,
XFS_AGB_TO_DADDR(mp, agno, XFS_IBT_BLOCK(mp)),
- BTOBB(mp->m_sb.sb_blocksize), XBF_MAPPED);
+ BTOBB(mp->m_sb.sb_blocksize), 0);
if (!bp) {
error = ENOMEM;
goto error0;
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 72ec1a4..a59eea0 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -150,6 +150,7 @@ xfs_imap_to_bp(
int ni;
xfs_buf_t *bp;

+ buf_flags |= XBF_UNMAPPED;
error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp, imap->im_blkno,
(int)imap->im_len, buf_flags, &bp);
if (error) {
diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
index 574e2e9..d7abe5f 100644
--- a/fs/xfs/xfs_log_recover.c
+++ b/fs/xfs/xfs_log_recover.c
@@ -2127,8 +2127,8 @@ xlog_recover_buffer_pass2(
trace_xfs_log_recover_buf_recover(log, buf_f);

buf_flags = 0;
- if (!(buf_f->blf_flags & XFS_BLF_INODE_BUF))
- buf_flags |= XBF_MAPPED;
+ if (buf_f->blf_flags & XFS_BLF_INODE_BUF)
+ buf_flags |= XBF_UNMAPPED;

bp = xfs_buf_read(mp->m_ddev_targp, buf_f->blf_blkno, buf_f->blf_len,
buf_flags);
diff --git a/fs/xfs/xfs_trans_buf.c b/fs/xfs/xfs_trans_buf.c
index d250afa..21c5a5e 100644
--- a/fs/xfs/xfs_trans_buf.c
+++ b/fs/xfs/xfs_trans_buf.c
@@ -138,9 +138,6 @@ xfs_trans_get_buf(xfs_trans_t *tp,
xfs_buf_t *bp;
xfs_buf_log_item_t *bip;

- if (flags == 0)
- flags = XBF_MAPPED;
-
/*
* Default to a normal get_buf() call if the tp is NULL.
*/
@@ -264,9 +261,6 @@ xfs_trans_read_buf(

*bpp = NULL;

- if (flags == 0)
- flags = XBF_MAPPED;
-
/*
* Default to a normal get_buf() call if the tp is NULL.
*/
diff --git a/fs/xfs/xfs_vnodeops.c b/fs/xfs/xfs_vnodeops.c
index 5b3f5b1..82b000f 100644
--- a/fs/xfs/xfs_vnodeops.c
+++ b/fs/xfs/xfs_vnodeops.c
@@ -79,8 +79,7 @@ xfs_readlink_bmap(
d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock);
byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);

- bp = xfs_buf_read(mp->m_ddev_targp, d, BTOBB(byte_cnt),
- XBF_MAPPED);
+ bp = xfs_buf_read(mp->m_ddev_targp, d, BTOBB(byte_cnt), 0);
if (!bp)
return XFS_ERROR(ENOMEM);
error = bp->b_error;
--
1.7.9.5