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Message-Id: <1274300694-8976-6-git-send-email-josef@redhat.com>
Date: Wed, 19 May 2010 16:24:54 -0400
From: Josef Bacik <josef@...hat.com>
To: linux-btrfs@...r.kernel.org, linux-fsdevel@...r.kernel.org,
linux-kernel@...r.kernel.org, hch@...radead.org,
akpm@...ux-foundation.org
Subject: [PATCH 6/6] Btrfs: do aio_write instead of write V2
V1->V2
-Fix some things that git rebase screwed up
-Use iov_iter_count() instead of count in a few places
-Update pos if we had a short read/write
In order for AIO to work, we need to implement aio_write. This patch converts
our btrfs_file_write to btrfs_aio_write. I've tested this with xfstests and
nothing broke, and the AIO stuff magically started working. Thanks,
Signed-off-by: Josef Bacik <josef@...hat.com>
---
fs/btrfs/extent_io.c | 11 +++-
fs/btrfs/file.c | 152 +++++++++++++++++++++++---------------------------
2 files changed, 80 insertions(+), 83 deletions(-)
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index d2d0368..c407f1c 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2020,6 +2020,7 @@ static int __extent_read_full_page(struct extent_io_tree *tree,
sector_t sector;
struct extent_map *em;
struct block_device *bdev;
+ struct btrfs_ordered_extent *ordered;
int ret;
int nr = 0;
size_t page_offset = 0;
@@ -2031,7 +2032,15 @@ static int __extent_read_full_page(struct extent_io_tree *tree,
set_page_extent_mapped(page);
end = page_end;
- lock_extent(tree, start, end, GFP_NOFS);
+ while (1) {
+ lock_extent(tree, start, end, GFP_NOFS);
+ ordered = btrfs_lookup_ordered_extent(inode, start);
+ if (!ordered)
+ break;
+ unlock_extent(tree, start, end, GFP_NOFS);
+ btrfs_start_ordered_extent(inode, ordered, 1);
+ btrfs_put_ordered_extent(ordered);
+ }
if (page->index == last_byte >> PAGE_CACHE_SHIFT) {
char *userpage;
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index dace07b..ce35431 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -46,32 +46,42 @@
static noinline int btrfs_copy_from_user(loff_t pos, int num_pages,
int write_bytes,
struct page **prepared_pages,
- const char __user *buf)
+ struct iov_iter *i)
{
- long page_fault = 0;
- int i;
+ size_t copied;
+ int pg = 0;
int offset = pos & (PAGE_CACHE_SIZE - 1);
- for (i = 0; i < num_pages && write_bytes > 0; i++, offset = 0) {
+ while (write_bytes > 0) {
size_t count = min_t(size_t,
PAGE_CACHE_SIZE - offset, write_bytes);
- struct page *page = prepared_pages[i];
- fault_in_pages_readable(buf, count);
+ struct page *page = prepared_pages[pg];
+again:
+ if (unlikely(iov_iter_fault_in_readable(i, count)))
+ return -EFAULT;
/* Copy data from userspace to the current page */
- kmap(page);
- page_fault = __copy_from_user(page_address(page) + offset,
- buf, count);
+ copied = iov_iter_copy_from_user(page, i, offset, count);
+
/* Flush processor's dcache for this page */
flush_dcache_page(page);
- kunmap(page);
- buf += count;
- write_bytes -= count;
+ iov_iter_advance(i, copied);
+ write_bytes -= copied;
- if (page_fault)
- break;
+ if (unlikely(copied == 0)) {
+ count = min_t(size_t, PAGE_CACHE_SIZE - offset,
+ iov_iter_single_seg_count(i));
+ goto again;
+ }
+
+ if (unlikely(copied < PAGE_CACHE_SIZE - offset)) {
+ offset += copied;
+ } else {
+ pg++;
+ offset = 0;
+ }
}
- return page_fault ? -EFAULT : 0;
+ return 0;
}
/*
@@ -823,60 +833,24 @@ again:
return 0;
}
-/* Copied from read-write.c */
-static void wait_on_retry_sync_kiocb(struct kiocb *iocb)
-{
- set_current_state(TASK_UNINTERRUPTIBLE);
- if (!kiocbIsKicked(iocb))
- schedule();
- else
- kiocbClearKicked(iocb);
- __set_current_state(TASK_RUNNING);
-}
-
-/*
- * Just a copy of what do_sync_write does.
- */
-static ssize_t __btrfs_direct_write(struct file *file, const char __user *buf,
- size_t count, loff_t pos, loff_t *ppos)
-{
- struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = count };
- unsigned long nr_segs = 1;
- struct kiocb kiocb;
- ssize_t ret;
-
- init_sync_kiocb(&kiocb, file);
- kiocb.ki_pos = pos;
- kiocb.ki_left = count;
- kiocb.ki_nbytes = count;
-
- while (1) {
- ret = generic_file_direct_write(&kiocb, &iov, &nr_segs, pos,
- ppos, count, count);
- if (ret != -EIOCBRETRY)
- break;
- wait_on_retry_sync_kiocb(&kiocb);
- }
-
- if (ret == -EIOCBQUEUED)
- ret = wait_on_sync_kiocb(&kiocb);
- *ppos = kiocb.ki_pos;
- return ret;
-}
-
-static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
- size_t count, loff_t *ppos)
+static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
+ const struct iovec *iov,
+ unsigned long nr_segs, loff_t pos)
{
- loff_t pos;
+ struct file *file = iocb->ki_filp;
+ struct inode *inode = fdentry(file)->d_inode;
+ struct btrfs_root *root = BTRFS_I(inode)->root;
+ struct page *pinned[2];
+ struct page **pages = NULL;
+ struct iov_iter i;
+ loff_t *ppos = &iocb->ki_pos;
loff_t start_pos;
ssize_t num_written = 0;
ssize_t err = 0;
+ size_t count;
+ size_t ocount;
int ret = 0;
- struct inode *inode = fdentry(file)->d_inode;
- struct btrfs_root *root = BTRFS_I(inode)->root;
- struct page **pages = NULL;
int nrptrs;
- struct page *pinned[2];
unsigned long first_index;
unsigned long last_index;
int will_write;
@@ -888,7 +862,6 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
pinned[0] = NULL;
pinned[1] = NULL;
- pos = *ppos;
start_pos = pos;
vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
@@ -902,6 +875,11 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
mutex_lock(&inode->i_mutex);
+ err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);
+ if (err)
+ goto out;
+ count = ocount;
+
current->backing_dev_info = inode->i_mapping->backing_dev_info;
err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
if (err)
@@ -918,14 +896,24 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
BTRFS_I(inode)->sequence++;
if (unlikely(file->f_flags & O_DIRECT)) {
- num_written = __btrfs_direct_write(file, buf, count, pos,
- ppos);
- pos += num_written;
- count -= num_written;
+ ret = btrfs_check_data_free_space(root, inode, count);
+ if (ret)
+ goto out;
- /* We've written everything we wanted to, exit */
- if (num_written < 0 || !count)
+ num_written = generic_file_direct_write(iocb, iov, &nr_segs,
+ pos, ppos, count,
+ ocount);
+
+ /* All reservations for DIO are done internally */
+ btrfs_free_reserved_data_space(root, inode, count);
+
+ if (num_written < 0) {
+ ret = num_written;
+ num_written = 0;
+ goto out;
+ } else if (num_written == count) {
goto out;
+ }
/*
* We are going to do buffered for the rest of the range, so we
@@ -933,18 +921,20 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
* done.
*/
buffered = 1;
- buf += num_written;
+ pos += num_written;
}
- nrptrs = min((count + PAGE_CACHE_SIZE - 1) / PAGE_CACHE_SIZE,
- PAGE_CACHE_SIZE / (sizeof(struct page *)));
+ iov_iter_init(&i, iov, nr_segs, count, num_written);
+ nrptrs = min((iov_iter_count(&i) + PAGE_CACHE_SIZE - 1) /
+ PAGE_CACHE_SIZE, PAGE_CACHE_SIZE /
+ (sizeof(struct page *)));
pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
/* generic_write_checks can change our pos */
start_pos = pos;
first_index = pos >> PAGE_CACHE_SHIFT;
- last_index = (pos + count) >> PAGE_CACHE_SHIFT;
+ last_index = (pos + iov_iter_count(&i)) >> PAGE_CACHE_SHIFT;
/*
* there are lots of better ways to do this, but this code
@@ -961,7 +951,7 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
unlock_page(pinned[0]);
}
}
- if ((pos + count) & (PAGE_CACHE_SIZE - 1)) {
+ if ((pos + iov_iter_count(&i)) & (PAGE_CACHE_SIZE - 1)) {
pinned[1] = grab_cache_page(inode->i_mapping, last_index);
if (!PageUptodate(pinned[1])) {
ret = btrfs_readpage(NULL, pinned[1]);
@@ -972,10 +962,10 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
}
}
- while (count > 0) {
+ while (iov_iter_count(&i) > 0) {
size_t offset = pos & (PAGE_CACHE_SIZE - 1);
- size_t write_bytes = min(count, nrptrs *
- (size_t)PAGE_CACHE_SIZE -
+ size_t write_bytes = min(iov_iter_count(&i),
+ nrptrs * (size_t)PAGE_CACHE_SIZE -
offset);
size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >>
PAGE_CACHE_SHIFT;
@@ -997,7 +987,7 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
}
ret = btrfs_copy_from_user(pos, num_pages,
- write_bytes, pages, buf);
+ write_bytes, pages, &i);
if (ret) {
btrfs_free_reserved_data_space(root, inode,
write_bytes);
@@ -1026,8 +1016,6 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
btrfs_throttle(root);
}
- buf += write_bytes;
- count -= write_bytes;
pos += write_bytes;
num_written += write_bytes;
@@ -1222,7 +1210,7 @@ const struct file_operations btrfs_file_operations = {
.read = do_sync_read,
.aio_read = generic_file_aio_read,
.splice_read = generic_file_splice_read,
- .write = btrfs_file_write,
+ .aio_write = btrfs_file_aio_write,
.mmap = btrfs_file_mmap,
.open = generic_file_open,
.release = btrfs_release_file,
--
1.6.6.1
--
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