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ocfs2: code clean up for direct io
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Clean up ocfs2_file_write_iter & ocfs2_prepare_inode_for_write:
 * remove append dio check: it will be checked in ocfs2_direct_IO()
 * remove file hole check: file hole is supported for now
 * remove inline data check: it will be checked in ocfs2_direct_IO()
 * remove the full_coherence check when append dio: we will get the
   inode_lock in ocfs2_dio_get_block, there is no need to fall back to
   buffer io to ensure the coherence semantics.

Now the drop dio procedure is gone.  :)

[[email protected]: remove unused label]
Signed-off-by: Ryan Ding <[email protected]>
Reviewed-by: Junxiao Bi <[email protected]>
Cc: Joseph Qi <[email protected]>
Cc: Mark Fasheh <[email protected]>
Cc: Joel Becker <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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@torvalds
Ryan Ding authored and torvalds committed Mar 25, 2016
1 parent c15471f commit f1f973f
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Showing 2 changed files with 10 additions and 144 deletions.
138 changes: 6 additions & 132 deletions fs/ocfs2/file.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1381,44 +1381,6 @@ static int __ocfs2_write_remove_suid(struct inode *inode,
return ret;
}

/*
* Will look for holes and unwritten extents in the range starting at
* pos for count bytes (inclusive).
*/
static int ocfs2_check_range_for_holes(struct inode *inode, loff_t pos,
size_t count)
{
int ret = 0;
unsigned int extent_flags;
u32 cpos, clusters, extent_len, phys_cpos;
struct super_block *sb = inode->i_sb;

cpos = pos >> OCFS2_SB(sb)->s_clustersize_bits;
clusters = ocfs2_clusters_for_bytes(sb, pos + count) - cpos;

while (clusters) {
ret = ocfs2_get_clusters(inode, cpos, &phys_cpos, &extent_len,
&extent_flags);
if (ret < 0) {
mlog_errno(ret);
goto out;
}

if (phys_cpos == 0 || (extent_flags & OCFS2_EXT_UNWRITTEN)) {
ret = 1;
break;
}

if (extent_len > clusters)
extent_len = clusters;

clusters -= extent_len;
cpos += extent_len;
}
out:
return ret;
}

static int ocfs2_write_remove_suid(struct inode *inode)
{
int ret;
Expand Down Expand Up @@ -2129,18 +2091,12 @@ static int ocfs2_prepare_inode_for_refcount(struct inode *inode,

static int ocfs2_prepare_inode_for_write(struct file *file,
loff_t pos,
size_t count,
int appending,
int *direct_io,
int *has_refcount)
size_t count)
{
int ret = 0, meta_level = 0;
struct dentry *dentry = file->f_path.dentry;
struct inode *inode = d_inode(dentry);
loff_t end;
struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
int full_coherency = !(osb->s_mount_opt &
OCFS2_MOUNT_COHERENCY_BUFFERED);

/*
* We start with a read level meta lock and only jump to an ex
Expand Down Expand Up @@ -2189,78 +2145,19 @@ static int ocfs2_prepare_inode_for_write(struct file *file,
pos,
count,
&meta_level);
if (has_refcount)
*has_refcount = 1;
if (direct_io)
*direct_io = 0;
}

if (ret < 0) {
mlog_errno(ret);
goto out_unlock;
}

/*
* Skip the O_DIRECT checks if we don't need
* them.
*/
if (!direct_io || !(*direct_io))
break;

/*
* There's no sane way to do direct writes to an inode
* with inline data.
*/
if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
*direct_io = 0;
break;
}

/*
* Allowing concurrent direct writes means
* i_size changes wouldn't be synchronized, so
* one node could wind up truncating another
* nodes writes.
*/
if (end > i_size_read(inode) && !full_coherency) {
*direct_io = 0;
break;
}

/*
* Fallback to old way if the feature bit is not set.
*/
if (end > i_size_read(inode) &&
!ocfs2_supports_append_dio(osb)) {
*direct_io = 0;
break;
}

/*
* We don't fill holes during direct io, so
* check for them here. If any are found, the
* caller will have to retake some cluster
* locks and initiate the io as buffered.
*/
ret = ocfs2_check_range_for_holes(inode, pos, count);
if (ret == 1) {
/*
* Fallback to old way if the feature bit is not set.
* Otherwise try dio first and then complete the rest
* request through buffer io.
*/
if (!ocfs2_supports_append_dio(osb))
*direct_io = 0;
ret = 0;
} else if (ret < 0)
mlog_errno(ret);
break;
}

out_unlock:
trace_ocfs2_prepare_inode_for_write(OCFS2_I(inode)->ip_blkno,
pos, appending, count,
direct_io, has_refcount);
pos, count);

if (meta_level >= 0)
ocfs2_inode_unlock(inode, meta_level);
Expand All @@ -2272,18 +2169,16 @@ static int ocfs2_prepare_inode_for_write(struct file *file,
static ssize_t ocfs2_file_write_iter(struct kiocb *iocb,
struct iov_iter *from)
{
int direct_io, appending, rw_level;
int can_do_direct, has_refcount = 0;
int direct_io, rw_level;
ssize_t written = 0;
ssize_t ret;
size_t count = iov_iter_count(from), orig_count;
size_t count = iov_iter_count(from);
struct file *file = iocb->ki_filp;
struct inode *inode = file_inode(file);
struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
int full_coherency = !(osb->s_mount_opt &
OCFS2_MOUNT_COHERENCY_BUFFERED);
int unaligned_dio = 0;
int dropped_dio = 0;
int append_write = ((iocb->ki_pos + count) >=
i_size_read(inode) ? 1 : 0);

Expand All @@ -2296,12 +2191,10 @@ static ssize_t ocfs2_file_write_iter(struct kiocb *iocb,
if (count == 0)
return 0;

appending = iocb->ki_flags & IOCB_APPEND ? 1 : 0;
direct_io = iocb->ki_flags & IOCB_DIRECT ? 1 : 0;

inode_lock(inode);

relock:
/*
* Concurrent O_DIRECT writes are allowed with
* mount_option "coherency=buffered".
Expand Down Expand Up @@ -2334,7 +2227,6 @@ static ssize_t ocfs2_file_write_iter(struct kiocb *iocb,
ocfs2_inode_unlock(inode, 1);
}

orig_count = iov_iter_count(from);
ret = generic_write_checks(iocb, from);
if (ret <= 0) {
if (ret)
Expand All @@ -2343,9 +2235,7 @@ static ssize_t ocfs2_file_write_iter(struct kiocb *iocb,
}
count = ret;

can_do_direct = direct_io;
ret = ocfs2_prepare_inode_for_write(file, iocb->ki_pos, count, appending,
&can_do_direct, &has_refcount);
ret = ocfs2_prepare_inode_for_write(file, iocb->ki_pos, count);
if (ret < 0) {
mlog_errno(ret);
goto out;
Expand All @@ -2354,22 +2244,6 @@ static ssize_t ocfs2_file_write_iter(struct kiocb *iocb,
if (direct_io && !is_sync_kiocb(iocb))
unaligned_dio = ocfs2_is_io_unaligned(inode, count, iocb->ki_pos);

/*
* We can't complete the direct I/O as requested, fall back to
* buffered I/O.
*/
if (direct_io && !can_do_direct) {
ocfs2_rw_unlock(inode, rw_level);

rw_level = -1;

direct_io = 0;
iocb->ki_flags &= ~IOCB_DIRECT;
iov_iter_reexpand(from, orig_count);
dropped_dio = 1;
goto relock;
}

if (unaligned_dio) {
/*
* Wait on previous unaligned aio to complete before
Expand Down Expand Up @@ -2405,7 +2279,7 @@ static ssize_t ocfs2_file_write_iter(struct kiocb *iocb,
goto no_sync;

if (((file->f_flags & O_DSYNC) && !direct_io) ||
IS_SYNC(inode) || dropped_dio) {
IS_SYNC(inode)) {
ret = filemap_fdatawrite_range(file->f_mapping,
iocb->ki_pos - written,
iocb->ki_pos - 1);
Expand Down
16 changes: 4 additions & 12 deletions fs/ocfs2/ocfs2_trace.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1450,28 +1450,20 @@ DEFINE_OCFS2_ULL_ULL_ULL_EVENT(ocfs2_remove_inode_range);

TRACE_EVENT(ocfs2_prepare_inode_for_write,
TP_PROTO(unsigned long long ino, unsigned long long saved_pos,
int appending, unsigned long count,
int *direct_io, int *has_refcount),
TP_ARGS(ino, saved_pos, appending, count, direct_io, has_refcount),
unsigned long count),
TP_ARGS(ino, saved_pos, count),
TP_STRUCT__entry(
__field(unsigned long long, ino)
__field(unsigned long long, saved_pos)
__field(int, appending)
__field(unsigned long, count)
__field(int, direct_io)
__field(int, has_refcount)
),
TP_fast_assign(
__entry->ino = ino;
__entry->saved_pos = saved_pos;
__entry->appending = appending;
__entry->count = count;
__entry->direct_io = direct_io ? *direct_io : -1;
__entry->has_refcount = has_refcount ? *has_refcount : -1;
),
TP_printk("%llu %llu %d %lu %d %d", __entry->ino,
__entry->saved_pos, __entry->appending, __entry->count,
__entry->direct_io, __entry->has_refcount)
TP_printk("%llu %llu %lu", __entry->ino,
__entry->saved_pos, __entry->count)
);

DEFINE_OCFS2_INT_EVENT(generic_file_aio_read_ret);
Expand Down

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