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remove SWRITE* I/O types 

These flags aren't real I/O types, but tell ll_rw_block to always
lock the buffer instead of giving up on a failed trylock.

Instead add a new write_dirty_buffer helper that implements this semantic
and use it from the existing SWRITE* callers.  Note that the ll_rw_block
code had a bug where it didn't promote WRITE_SYNC_PLUG properly, which
this patch fixes.

In the ufs code clean up the helper that used to call ll_rw_block
to mirror sync_dirty_buffer, which is the function it implements for
compound buffers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Christoph Hellwig 2010-08-11 17:06:24 +02:00 committed by Al Viro
parent 87e99511ea
commit 9cb569d601
16 changed files with 73 additions and 94 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

50
fs/buffer.c
View File

@ -770,11 +770,12 @@ static int fsync_buffers_list(spinlock_t *lock, struct list_head *list)
spin_unlock(lock);
/*
* Ensure any pending I/O completes so that
* ll_rw_block() actually writes the current
* contents - it is a noop if I/O is still in
* flight on potentially older contents.
* write_dirty_buffer() actually writes the
* current contents - it is a noop if I/O is
* still in flight on potentially older
* contents.
*/
ll_rw_block(SWRITE_SYNC_PLUG, 1, &bh);
write_dirty_buffer(bh, WRITE_SYNC_PLUG);
/*
* Kick off IO for the previous mapping. Note
@ -2949,22 +2950,21 @@ EXPORT_SYMBOL(submit_bh);
/**
* ll_rw_block: low-level access to block devices (DEPRECATED)
* @rw: whether to %READ or %WRITE or %SWRITE or maybe %READA (readahead)
* @rw: whether to %READ or %WRITE or maybe %READA (readahead)
* @nr: number of &struct buffer_heads in the array
* @bhs: array of pointers to &struct buffer_head
*
* ll_rw_block() takes an array of pointers to &struct buffer_heads, and
* requests an I/O operation on them, either a %READ or a %WRITE. The third
* %SWRITE is like %WRITE only we make sure that the *current* data in buffers
* are sent to disk. The fourth %READA option is described in the documentation
* for generic_make_request() which ll_rw_block() calls.
* %READA option is described in the documentation for generic_make_request()
* which ll_rw_block() calls.
*
* This function drops any buffer that it cannot get a lock on (with the
* BH_Lock state bit) unless SWRITE is required, any buffer that appears to be
* clean when doing a write request, and any buffer that appears to be
* up-to-date when doing read request. Further it marks as clean buffers that
* are processed for writing (the buffer cache won't assume that they are
* actually clean until the buffer gets unlocked).
* BH_Lock state bit), any buffer that appears to be clean when doing a write
* request, and any buffer that appears to be up-to-date when doing read
* request. Further it marks as clean buffers that are processed for
* writing (the buffer cache won't assume that they are actually clean
* until the buffer gets unlocked).
*
* ll_rw_block sets b_end_io to simple completion handler that marks
* the buffer up-to-date (if approriate), unlocks the buffer and wakes
@ -2980,19 +2980,12 @@ void ll_rw_block(int rw, int nr, struct buffer_head *bhs[])
for (i = 0; i < nr; i++) {
struct buffer_head *bh = bhs[i];
if (rw == SWRITE || rw == SWRITE_SYNC || rw == SWRITE_SYNC_PLUG)
lock_buffer(bh);
else if (!trylock_buffer(bh))
if (!trylock_buffer(bh))
continue;
if (rw == WRITE || rw == SWRITE || rw == SWRITE_SYNC ||
rw == SWRITE_SYNC_PLUG) {
if (rw == WRITE) {
if (test_clear_buffer_dirty(bh)) {
bh->b_end_io = end_buffer_write_sync;
get_bh(bh);
if (rw == SWRITE_SYNC)
submit_bh(WRITE_SYNC, bh);
else
submit_bh(WRITE, bh);
continue;
}
@ -3009,6 +3002,19 @@ void ll_rw_block(int rw, int nr, struct buffer_head *bhs[])
}
EXPORT_SYMBOL(ll_rw_block);
void write_dirty_buffer(struct buffer_head *bh, int rw)
{
lock_buffer(bh);
if (!test_clear_buffer_dirty(bh)) {
unlock_buffer(bh);
return;
}
bh->b_end_io = end_buffer_write_sync;
get_bh(bh);
submit_bh(rw, bh);
}
EXPORT_SYMBOL(write_dirty_buffer);
/*
* For a data-integrity writeout, we need to wait upon any in-progress I/O
* and then start new I/O and then wait upon it. The caller must have a ref on

4
fs/fat/misc.c
View File

@ -250,7 +250,9 @@ int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs)
{
int i, err = 0;
ll_rw_block(SWRITE, nr_bhs, bhs);
for (i = 0; i < nr_bhs; i++)
write_dirty_buffer(bhs[i], WRITE);
for (i = 0; i < nr_bhs; i++) {
wait_on_buffer(bhs[i]);
if (buffer_eopnotsupp(bhs[i])) {

4
fs/jbd/checkpoint.c
View File

@ -254,7 +254,9 @@ __flush_batch(journal_t *journal, struct buffer_head **bhs, int *batch_count)
{
int i;
ll_rw_block(SWRITE, *batch_count, bhs);
for (i = 0; i < *batch_count; i++)
write_dirty_buffer(bhs[i], WRITE);
for (i = 0; i < *batch_count; i++) {
struct buffer_head *bh = bhs[i];
clear_buffer_jwrite(bh);

2
fs/jbd/journal.c
View File

@ -1024,7 +1024,7 @@ void journal_update_superblock(journal_t *journal, int wait)
if (wait)
sync_dirty_buffer(bh);
else
ll_rw_block(SWRITE, 1, &bh);
write_dirty_buffer(bh, WRITE);
out:
/* If we have just flushed the log (by marking s_start==0), then

2
fs/jbd/revoke.c
View File

@ -617,7 +617,7 @@ static void flush_descriptor(journal_t *journal,
set_buffer_jwrite(bh);
BUFFER_TRACE(bh, "write");
set_buffer_dirty(bh);
ll_rw_block((write_op == WRITE) ? SWRITE : SWRITE_SYNC_PLUG, 1, &bh);
write_dirty_buffer(bh, write_op);
}
#endif

4
fs/jbd2/checkpoint.c
View File

@ -255,7 +255,9 @@ __flush_batch(journal_t *journal, int *batch_count)
{
int i;
ll_rw_block(SWRITE, *batch_count, journal->j_chkpt_bhs);
for (i = 0; i < *batch_count; i++)
write_dirty_buffer(journal->j_chkpt_bhs[i], WRITE);
for (i = 0; i < *batch_count; i++) {
struct buffer_head *bh = journal->j_chkpt_bhs[i];
clear_buffer_jwrite(bh);

2
fs/jbd2/journal.c
View File

@ -1124,7 +1124,7 @@ void jbd2_journal_update_superblock(journal_t *journal, int wait)
set_buffer_uptodate(bh);
}
} else
ll_rw_block(SWRITE, 1, &bh);
write_dirty_buffer(bh, WRITE);
out:
/* If we have just flushed the log (by marking s_start==0), then

2
fs/jbd2/revoke.c
View File

@ -625,7 +625,7 @@ static void flush_descriptor(journal_t *journal,
set_buffer_jwrite(bh);
BUFFER_TRACE(bh, "write");
set_buffer_dirty(bh);
ll_rw_block((write_op == WRITE) ? SWRITE : SWRITE_SYNC_PLUG, 1, &bh);
write_dirty_buffer(bh, write_op);
}
#endif

2
fs/reiserfs/journal.c
View File

@ -2311,7 +2311,7 @@ static int journal_read_transaction(struct super_block *sb,
/* flush out the real blocks */
for (i = 0; i < get_desc_trans_len(desc); i++) {
set_buffer_dirty(real_blocks[i]);
ll_rw_block(SWRITE, 1, real_blocks + i);
write_dirty_buffer(real_blocks[i], WRITE);
}
for (i = 0; i < get_desc_trans_len(desc); i++) {
wait_on_buffer(real_blocks[i]);

24
fs/ufs/balloc.c
View File

@ -114,10 +114,8 @@ void ufs_free_fragments(struct inode *inode, u64 fragment, unsigned count)
ubh_mark_buffer_dirty (USPI_UBH(uspi));
ubh_mark_buffer_dirty (UCPI_UBH(ucpi));
if (sb->s_flags & MS_SYNCHRONOUS) {
ubh_ll_rw_block(SWRITE, UCPI_UBH(ucpi));
ubh_wait_on_buffer (UCPI_UBH(ucpi));
}
if (sb->s_flags & MS_SYNCHRONOUS)
ubh_sync_block(UCPI_UBH(ucpi));
sb->s_dirt = 1;
unlock_super (sb);
@ -207,10 +205,8 @@ do_more:
ubh_mark_buffer_dirty (USPI_UBH(uspi));
ubh_mark_buffer_dirty (UCPI_UBH(ucpi));
if (sb->s_flags & MS_SYNCHRONOUS) {
ubh_ll_rw_block(SWRITE, UCPI_UBH(ucpi));
ubh_wait_on_buffer (UCPI_UBH(ucpi));
}
if (sb->s_flags & MS_SYNCHRONOUS)
ubh_sync_block(UCPI_UBH(ucpi));
if (overflow) {
fragment += count;
@ -558,10 +554,8 @@ static u64 ufs_add_fragments(struct inode *inode, u64 fragment,
ubh_mark_buffer_dirty (USPI_UBH(uspi));
ubh_mark_buffer_dirty (UCPI_UBH(ucpi));
if (sb->s_flags & MS_SYNCHRONOUS) {
ubh_ll_rw_block(SWRITE, UCPI_UBH(ucpi));
ubh_wait_on_buffer (UCPI_UBH(ucpi));
}
if (sb->s_flags & MS_SYNCHRONOUS)
ubh_sync_block(UCPI_UBH(ucpi));
sb->s_dirt = 1;
UFSD("EXIT, fragment %llu\n", (unsigned long long)fragment);
@ -680,10 +674,8 @@ cg_found:
succed:
ubh_mark_buffer_dirty (USPI_UBH(uspi));
ubh_mark_buffer_dirty (UCPI_UBH(ucpi));
if (sb->s_flags & MS_SYNCHRONOUS) {
ubh_ll_rw_block(SWRITE, UCPI_UBH(ucpi));
ubh_wait_on_buffer (UCPI_UBH(ucpi));
}
if (sb->s_flags & MS_SYNCHRONOUS)
ubh_sync_block(UCPI_UBH(ucpi));
sb->s_dirt = 1;
result += cgno * uspi->s_fpg;

18
fs/ufs/ialloc.c
View File

@ -113,10 +113,8 @@ void ufs_free_inode (struct inode * inode)
ubh_mark_buffer_dirty (USPI_UBH(uspi));
ubh_mark_buffer_dirty (UCPI_UBH(ucpi));
if (sb->s_flags & MS_SYNCHRONOUS) {
ubh_ll_rw_block(SWRITE, UCPI_UBH(ucpi));
ubh_wait_on_buffer (UCPI_UBH(ucpi));
}
if (sb->s_flags & MS_SYNCHRONOUS)
ubh_sync_block(UCPI_UBH(ucpi));
sb->s_dirt = 1;
unlock_super (sb);
@ -156,10 +154,8 @@ static void ufs2_init_inodes_chunk(struct super_block *sb,
fs32_add(sb, &ucg->cg_u.cg_u2.cg_initediblk, uspi->s_inopb);
ubh_mark_buffer_dirty(UCPI_UBH(ucpi));
if (sb->s_flags & MS_SYNCHRONOUS) {
ubh_ll_rw_block(SWRITE, UCPI_UBH(ucpi));
ubh_wait_on_buffer(UCPI_UBH(ucpi));
}
if (sb->s_flags & MS_SYNCHRONOUS)
ubh_sync_block(UCPI_UBH(ucpi));
UFSD("EXIT\n");
}
@ -290,10 +286,8 @@ cg_found:
}
ubh_mark_buffer_dirty (USPI_UBH(uspi));
ubh_mark_buffer_dirty (UCPI_UBH(ucpi));
if (sb->s_flags & MS_SYNCHRONOUS) {
ubh_ll_rw_block(SWRITE, UCPI_UBH(ucpi));
ubh_wait_on_buffer (UCPI_UBH(ucpi));
}
if (sb->s_flags & MS_SYNCHRONOUS)
ubh_sync_block(UCPI_UBH(ucpi));
sb->s_dirt = 1;
inode->i_ino = cg * uspi->s_ipg + bit;

18
fs/ufs/truncate.c
View File

@ -243,10 +243,8 @@ static int ufs_trunc_indirect(struct inode *inode, u64 offset, void *p)
ubh_bforget(ind_ubh);
ind_ubh = NULL;
}
if (IS_SYNC(inode) && ind_ubh && ubh_buffer_dirty(ind_ubh)) {
ubh_ll_rw_block(SWRITE, ind_ubh);
ubh_wait_on_buffer (ind_ubh);
}
if (IS_SYNC(inode) && ind_ubh && ubh_buffer_dirty(ind_ubh))
ubh_sync_block(ind_ubh);
ubh_brelse (ind_ubh);
UFSD("EXIT: ino %lu\n", inode->i_ino);
@ -307,10 +305,8 @@ static int ufs_trunc_dindirect(struct inode *inode, u64 offset, void *p)
ubh_bforget(dind_bh);
dind_bh = NULL;
}
if (IS_SYNC(inode) && dind_bh && ubh_buffer_dirty(dind_bh)) {
ubh_ll_rw_block(SWRITE, dind_bh);
ubh_wait_on_buffer (dind_bh);
}
if (IS_SYNC(inode) && dind_bh && ubh_buffer_dirty(dind_bh))
ubh_sync_block(dind_bh);
ubh_brelse (dind_bh);
UFSD("EXIT: ino %lu\n", inode->i_ino);
@ -367,10 +363,8 @@ static int ufs_trunc_tindirect(struct inode *inode)
ubh_bforget(tind_bh);
tind_bh = NULL;
}
if (IS_SYNC(inode) && tind_bh && ubh_buffer_dirty(tind_bh)) {
ubh_ll_rw_block(SWRITE, tind_bh);
ubh_wait_on_buffer (tind_bh);
}
if (IS_SYNC(inode) && tind_bh && ubh_buffer_dirty(tind_bh))
ubh_sync_block(tind_bh);
ubh_brelse (tind_bh);
UFSD("EXIT: ino %lu\n", inode->i_ino);

22
fs/ufs/util.c
View File

@ -113,21 +113,17 @@ void ubh_mark_buffer_uptodate (struct ufs_buffer_head * ubh, int flag)
}
}
void ubh_ll_rw_block(int rw, struct ufs_buffer_head *ubh)
{
if (!ubh)
return;
ll_rw_block(rw, ubh->count, ubh->bh);
}
void ubh_wait_on_buffer (struct ufs_buffer_head * ubh)
void ubh_sync_block(struct ufs_buffer_head *ubh)
{
if (ubh) {
unsigned i;
if (!ubh)
return;
for ( i = 0; i < ubh->count; i++ )
wait_on_buffer (ubh->bh[i]);
for (i = 0; i < ubh->count; i++)
write_dirty_buffer(ubh->bh[i], WRITE);
for (i = 0; i < ubh->count; i++)
wait_on_buffer(ubh->bh[i]);
}
}
void ubh_bforget (struct ufs_buffer_head * ubh)

3
fs/ufs/util.h
View File

@ -269,8 +269,7 @@ extern void ubh_brelse (struct ufs_buffer_head *);
extern void ubh_brelse_uspi (struct ufs_sb_private_info *);
extern void ubh_mark_buffer_dirty (struct ufs_buffer_head *);
extern void ubh_mark_buffer_uptodate (struct ufs_buffer_head *, int);
extern void ubh_ll_rw_block(int, struct ufs_buffer_head *);
extern void ubh_wait_on_buffer (struct ufs_buffer_head *);
extern void ubh_sync_block(struct ufs_buffer_head *);
extern void ubh_bforget (struct ufs_buffer_head *);
extern int ubh_buffer_dirty (struct ufs_buffer_head *);
#define ubh_ubhcpymem(mem,ubh,size) _ubh_ubhcpymem_(uspi,mem,ubh,size)

1
include/linux/buffer_head.h
View File

@ -182,6 +182,7 @@ void __lock_buffer(struct buffer_head *bh);
void ll_rw_block(int, int, struct buffer_head * bh[]);
int sync_dirty_buffer(struct buffer_head *bh);
int __sync_dirty_buffer(struct buffer_head *bh, int rw);
void write_dirty_buffer(struct buffer_head *bh, int rw);
int submit_bh(int, struct buffer_head *);
void write_boundary_block(struct block_device *bdev,
sector_t bblock, unsigned blocksize);

9
include/linux/fs.h
View File

@ -125,9 +125,6 @@ struct inodes_stat_t {
* block layer could (in theory) choose to ignore this
* request if it runs into resource problems.
* WRITE A normal async write. Device will be plugged.
* SWRITE Like WRITE, but a special case for ll_rw_block() that
* tells it to lock the buffer first. Normally a buffer
* must be locked before doing IO.
* WRITE_SYNC_PLUG Synchronous write. Identical to WRITE, but passes down
* the hint that someone will be waiting on this IO
* shortly. The device must still be unplugged explicitly,
@ -138,9 +135,6 @@ struct inodes_stat_t {
* immediately after submission. The write equivalent
* of READ_SYNC.
* WRITE_ODIRECT_PLUG Special case write for O_DIRECT only.
* SWRITE_SYNC
* SWRITE_SYNC_PLUG Like WRITE_SYNC/WRITE_SYNC_PLUG, but locks the buffer.
* See SWRITE.
* WRITE_BARRIER Like WRITE_SYNC, but tells the block layer that all
* previously submitted writes must be safely on storage
* before this one is started. Also guarantees that when
@ -155,7 +149,6 @@ struct inodes_stat_t {
#define READ 0
#define WRITE RW_MASK
#define READA RWA_MASK
#define SWRITE (WRITE | READA)
#define READ_SYNC (READ | REQ_SYNC | REQ_UNPLUG)
#define READ_META (READ | REQ_META)
@ -165,8 +158,6 @@ struct inodes_stat_t {
#define WRITE_META (WRITE | REQ_META)
#define WRITE_BARRIER (WRITE | REQ_SYNC | REQ_NOIDLE | REQ_UNPLUG | \
REQ_HARDBARRIER)
#define SWRITE_SYNC_PLUG (SWRITE | REQ_SYNC | REQ_NOIDLE)
#define SWRITE_SYNC (SWRITE | REQ_SYNC | REQ_NOIDLE | REQ_UNPLUG)
/*
* These aren't really reads or writes, they pass down information about