subject:"\[PATCH 05\/10\] fs\: return if direct write will trigger writeback"

[PATCH 05/10] fs: return if direct write will trigger writeback

2017-06-06 Thread Goldwyn Rodrigues

From: Goldwyn Rodrigues 

Find out if the write will trigger a wait due to writeback. If yes,
return -EAGAIN.

Return -EINVAL for buffered AIO: there are multiple causes of
delay such as page locks, dirty throttling logic, page loading
from disk etc. which cannot be taken care of.

Reviewed-by: Christoph Hellwig 
Reviewed-by: Jan Kara 
Signed-off-by: Goldwyn Rodrigues 
---
 mm/filemap.c | 17 ++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/mm/filemap.c b/mm/filemap.c
index 097213275461..bc146efa6815 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2675,6 +2675,9 @@ inline ssize_t generic_write_checks(struct kiocb *iocb, 
struct iov_iter *from)
 
pos = iocb->ki_pos;
 
+   if ((iocb->ki_flags & IOCB_NOWAIT) && !(iocb->ki_flags & IOCB_DIRECT))
+   return -EINVAL;
+
if (limit != RLIM_INFINITY) {
if (iocb->ki_pos >= limit) {
send_sig(SIGXFSZ, current, 0);
@@ -2743,9 +2746,17 @@ generic_file_direct_write(struct kiocb *iocb, struct 
iov_iter *from)
write_len = iov_iter_count(from);
end = (pos + write_len - 1) >> PAGE_SHIFT;
 
-   written = filemap_write_and_wait_range(mapping, pos, pos + write_len - 
1);
-   if (written)
-   goto out;
+   if (iocb->ki_flags & IOCB_NOWAIT) {
+   /* If there are pages to writeback, return */
+   if (filemap_range_has_page(inode->i_mapping, pos,
+  pos + iov_iter_count(from)))
+   return -EAGAIN;
+   } else {
+   written = filemap_write_and_wait_range(mapping, pos,
+   pos + write_len - 1);
+   if (written)
+   goto out;
+   }
 
/*
 * After a write we want buffered reads to be sure to go to disk to get
-- 
2.12.0

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[PATCH 05/10] fs: return if direct write will trigger writeback

2017-06-04 Thread Goldwyn Rodrigues

From: Goldwyn Rodrigues 

Find out if the write will trigger a wait due to writeback. If yes,
return -EAGAIN.

Return -EINVAL for buffered AIO: there are multiple causes of
delay such as page locks, dirty throttling logic, page loading
from disk etc. which cannot be taken care of.

Reviewed-by: Christoph Hellwig 
Reviewed-by: Jan Kara 
Signed-off-by: Goldwyn Rodrigues 
---
 mm/filemap.c | 17 ++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/mm/filemap.c b/mm/filemap.c
index 097213275461..bc146efa6815 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2675,6 +2675,9 @@ inline ssize_t generic_write_checks(struct kiocb *iocb, 
struct iov_iter *from)
 
pos = iocb->ki_pos;
 
+   if ((iocb->ki_flags & IOCB_NOWAIT) && !(iocb->ki_flags & IOCB_DIRECT))
+   return -EINVAL;
+
if (limit != RLIM_INFINITY) {
if (iocb->ki_pos >= limit) {
send_sig(SIGXFSZ, current, 0);
@@ -2743,9 +2746,17 @@ generic_file_direct_write(struct kiocb *iocb, struct 
iov_iter *from)
write_len = iov_iter_count(from);
end = (pos + write_len - 1) >> PAGE_SHIFT;
 
-   written = filemap_write_and_wait_range(mapping, pos, pos + write_len - 
1);
-   if (written)
-   goto out;
+   if (iocb->ki_flags & IOCB_NOWAIT) {
+   /* If there are pages to writeback, return */
+   if (filemap_range_has_page(inode->i_mapping, pos,
+  pos + iov_iter_count(from)))
+   return -EAGAIN;
+   } else {
+   written = filemap_write_and_wait_range(mapping, pos,
+   pos + write_len - 1);
+   if (written)
+   goto out;
+   }
 
/*
 * After a write we want buffered reads to be sure to go to disk to get
-- 
2.12.0

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Re: [PATCH 05/10] fs: return if direct write will trigger writeback

2017-05-25 Thread Jan Kara

On Wed 24-05-17 11:41:45, Goldwyn Rodrigues wrote:
> From: Goldwyn Rodrigues 
> 
> Find out if the write will trigger a wait due to writeback. If yes,
> return -EAGAIN.
> 
> Return -EINVAL for buffered AIO: there are multiple causes of
> delay such as page locks, dirty throttling logic, page loading
> from disk etc. which cannot be taken care of.
> 
> Signed-off-by: Goldwyn Rodrigues 
> Reviewed-by: Christoph Hellwig 

Looks good. You can add:

Reviewed-by: Jan Kara 

Honza

> ---
>  mm/filemap.c | 17 ++---
>  1 file changed, 14 insertions(+), 3 deletions(-)
> 
> diff --git a/mm/filemap.c b/mm/filemap.c
> index 097213275461..bc146efa6815 100644
> --- a/mm/filemap.c
> +++ b/mm/filemap.c
> @@ -2675,6 +2675,9 @@ inline ssize_t generic_write_checks(struct kiocb *iocb, 
> struct iov_iter *from)
>  
>   pos = iocb->ki_pos;
>  
> + if ((iocb->ki_flags & IOCB_NOWAIT) && !(iocb->ki_flags & IOCB_DIRECT))
> + return -EINVAL;
> +
>   if (limit != RLIM_INFINITY) {
>   if (iocb->ki_pos >= limit) {
>   send_sig(SIGXFSZ, current, 0);
> @@ -2743,9 +2746,17 @@ generic_file_direct_write(struct kiocb *iocb, struct 
> iov_iter *from)
>   write_len = iov_iter_count(from);
>   end = (pos + write_len - 1) >> PAGE_SHIFT;
>  
> - written = filemap_write_and_wait_range(mapping, pos, pos + write_len - 
> 1);
> - if (written)
> - goto out;
> + if (iocb->ki_flags & IOCB_NOWAIT) {
> + /* If there are pages to writeback, return */
> + if (filemap_range_has_page(inode->i_mapping, pos,
> +pos + iov_iter_count(from)))
> + return -EAGAIN;
> + } else {
> + written = filemap_write_and_wait_range(mapping, pos,
> + pos + write_len - 1);
> + if (written)
> + goto out;
> + }
>  
>   /*
>* After a write we want buffered reads to be sure to go to disk to get
> -- 
> 2.12.0
> 
-- 
Jan Kara 
SUSE Labs, CR
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[PATCH 05/10] fs: return if direct write will trigger writeback

2017-05-24 Thread Goldwyn Rodrigues

From: Goldwyn Rodrigues 

Find out if the write will trigger a wait due to writeback. If yes,
return -EAGAIN.

Return -EINVAL for buffered AIO: there are multiple causes of
delay such as page locks, dirty throttling logic, page loading
from disk etc. which cannot be taken care of.

Signed-off-by: Goldwyn Rodrigues 
Reviewed-by: Christoph Hellwig 
---
 mm/filemap.c | 17 ++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/mm/filemap.c b/mm/filemap.c
index 097213275461..bc146efa6815 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2675,6 +2675,9 @@ inline ssize_t generic_write_checks(struct kiocb *iocb, 
struct iov_iter *from)
 
pos = iocb->ki_pos;
 
+   if ((iocb->ki_flags & IOCB_NOWAIT) && !(iocb->ki_flags & IOCB_DIRECT))
+   return -EINVAL;
+
if (limit != RLIM_INFINITY) {
if (iocb->ki_pos >= limit) {
send_sig(SIGXFSZ, current, 0);
@@ -2743,9 +2746,17 @@ generic_file_direct_write(struct kiocb *iocb, struct 
iov_iter *from)
write_len = iov_iter_count(from);
end = (pos + write_len - 1) >> PAGE_SHIFT;
 
-   written = filemap_write_and_wait_range(mapping, pos, pos + write_len - 
1);
-   if (written)
-   goto out;
+   if (iocb->ki_flags & IOCB_NOWAIT) {
+   /* If there are pages to writeback, return */
+   if (filemap_range_has_page(inode->i_mapping, pos,
+  pos + iov_iter_count(from)))
+   return -EAGAIN;
+   } else {
+   written = filemap_write_and_wait_range(mapping, pos,
+   pos + write_len - 1);
+   if (written)
+   goto out;
+   }
 
/*
 * After a write we want buffered reads to be sure to go to disk to get
-- 
2.12.0

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[PATCH 05/10] fs: return if direct write will trigger writeback

2017-05-11 Thread Goldwyn Rodrigues

From: Goldwyn Rodrigues 

Find out if the write will trigger a wait due to writeback. If yes,
return -EAGAIN.

Return -EINVAL for buffered AIO: there are multiple causes of
delay such as page locks, dirty throttling logic, page loading
from disk etc. which cannot be taken care of.

Signed-off-by: Goldwyn Rodrigues 
Reviewed-by: Christoph Hellwig 
---
 mm/filemap.c | 17 ++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/mm/filemap.c b/mm/filemap.c
index ca3031f505f2..fd7d175b3dee 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2673,6 +2673,9 @@ inline ssize_t generic_write_checks(struct kiocb *iocb, 
struct iov_iter *from)
 
pos = iocb->ki_pos;
 
+   if ((iocb->ki_flags & IOCB_NOWAIT) && !(iocb->ki_flags & IOCB_DIRECT))
+   return -EINVAL;
+
if (limit != RLIM_INFINITY) {
if (iocb->ki_pos >= limit) {
send_sig(SIGXFSZ, current, 0);
@@ -2742,9 +2745,17 @@ generic_file_direct_write(struct kiocb *iocb, struct 
iov_iter *from)
write_len = iov_iter_count(from);
end = (pos + write_len - 1) >> PAGE_SHIFT;
 
-   written = filemap_write_and_wait_range(mapping, pos, pos + write_len - 
1);
-   if (written)
-   goto out;
+   if (iocb->ki_flags & IOCB_NOWAIT) {
+   /* If there are pages to writeback, return */
+   if (filemap_range_has_page(inode->i_mapping, pos,
+  pos + iov_iter_count(from)))
+   return -EAGAIN;
+   } else {
+   written = filemap_write_and_wait_range(mapping, pos,
+   pos + write_len - 1);
+   if (written)
+   goto out;
+   }
 
/*
 * After a write we want buffered reads to be sure to go to disk to get
-- 
2.12.0

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[PATCH 05/10] fs: return if direct write will trigger writeback

[PATCH 05/10] fs: return if direct write will trigger writeback

Re: [PATCH 05/10] fs: return if direct write will trigger writeback

[PATCH 05/10] fs: return if direct write will trigger writeback

[PATCH 05/10] fs: return if direct write will trigger writeback

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