Re: [PATCH v2] xfs: Honor FALLOC_FL_KEEP_SIZE when punching ends of files
On 03/21/2017 04:39 AM, Brian Foster wrote:
On Sun, Mar 19, 2017 at 09:54:51PM -0700, Calvin Owens wrote:
When punching past EOF on XFS, fallocate(mode=PUNCH_HOLE|KEEP_SIZE) will
round the file size up to the nearest multiple of PAGE_SIZE:
calvinow@vm-disks/generic-xfs-1 ~$ dd if=/dev/urandom of=test bs=2048 count=1
calvinow@vm-disks/generic-xfs-1 ~$ stat test
Size: 2048Blocks: 8 IO Block: 4096 regular file
calvinow@vm-disks/generic-xfs-1 ~$ fallocate -n -l 2048 -o 2048 -p test
calvinow@vm-disks/generic-xfs-1 ~$ stat test
Size: 4096Blocks: 8 IO Block: 4096 regular file
Commit 3c2bdc912a1cc050 ("xfs: kill xfs_zero_remaining_bytes") replaced
xfs_zero_remaining_bytes() with calls to iomap helpers. The new helpers
don't enforce that [pos,offset) lies strictly on [0,i_size) when being
called from xfs_free_file_space(), so by "leaking" these ranges into
xfs_zero_range() we get this buggy behavior.
Fix this by reintroducing the checks xfs_zero_remaining_bytes() did
against i_size at the bottom of xfs_free_file_space().
Reported-by: Aaron Gao
Fixes: 3c2bdc912a1cc050 ("xfs: kill xfs_zero_remaining_bytes")
Cc: Christoph Hellwig
Cc: # 4.8+
Signed-off-by: Calvin Owens
---
fs/xfs/xfs_bmap_util.c | 11 +++
1 file changed, 11 insertions(+)
diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index 8b75dce..0796ebc 100644
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -1309,6 +1309,17 @@ xfs_free_file_space(
}
/*
+* Avoid doing I/O beyond eof - it's not necessary
+* since nothing can read beyond eof. The space will
+* be zeroed when the file is extended anyway.
+*/
I'd suggest to update the comment below with this information and move
the following bits down below it as well.
Will do.
+ if (offset >= XFS_ISIZE(ip))
+ return 0;
+
+ if ((offset + len) >= XFS_ISIZE(ip))
+ len = XFS_ISIZE(ip) - offset - 1;
+
This looks like an off-by-one. Do you mean the following?
if (offset + len > XFS_ISIZE(ip))
len = XFS_ISIZE(ip) - offset;
It's not an off-by-one (it's self-consistent), but your way makes more
sense, I'll fix it ;)
Thanks,
Calvin
Brian
+ /*
* Now that we've unmap all full blocks we'll have to zero out any
* partial block at the beginning and/or end. xfs_zero_range is
* smart enough to skip any holes, including those we just created.
--
2.9.3
--
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Re: [PATCH v2] xfs: Honor FALLOC_FL_KEEP_SIZE when punching ends of files
On 03/21/2017 04:39 AM, Brian Foster wrote:
On Sun, Mar 19, 2017 at 09:54:51PM -0700, Calvin Owens wrote:
When punching past EOF on XFS, fallocate(mode=PUNCH_HOLE|KEEP_SIZE) will
round the file size up to the nearest multiple of PAGE_SIZE:
calvinow@vm-disks/generic-xfs-1 ~$ dd if=/dev/urandom of=test bs=2048 count=1
calvinow@vm-disks/generic-xfs-1 ~$ stat test
Size: 2048Blocks: 8 IO Block: 4096 regular file
calvinow@vm-disks/generic-xfs-1 ~$ fallocate -n -l 2048 -o 2048 -p test
calvinow@vm-disks/generic-xfs-1 ~$ stat test
Size: 4096Blocks: 8 IO Block: 4096 regular file
Commit 3c2bdc912a1cc050 ("xfs: kill xfs_zero_remaining_bytes") replaced
xfs_zero_remaining_bytes() with calls to iomap helpers. The new helpers
don't enforce that [pos,offset) lies strictly on [0,i_size) when being
called from xfs_free_file_space(), so by "leaking" these ranges into
xfs_zero_range() we get this buggy behavior.
Fix this by reintroducing the checks xfs_zero_remaining_bytes() did
against i_size at the bottom of xfs_free_file_space().
Reported-by: Aaron Gao
Fixes: 3c2bdc912a1cc050 ("xfs: kill xfs_zero_remaining_bytes")
Cc: Christoph Hellwig
Cc: # 4.8+
Signed-off-by: Calvin Owens
---
fs/xfs/xfs_bmap_util.c | 11 +++
1 file changed, 11 insertions(+)
diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index 8b75dce..0796ebc 100644
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -1309,6 +1309,17 @@ xfs_free_file_space(
}
/*
+* Avoid doing I/O beyond eof - it's not necessary
+* since nothing can read beyond eof. The space will
+* be zeroed when the file is extended anyway.
+*/
I'd suggest to update the comment below with this information and move
the following bits down below it as well.
Will do.
+ if (offset >= XFS_ISIZE(ip))
+ return 0;
+
+ if ((offset + len) >= XFS_ISIZE(ip))
+ len = XFS_ISIZE(ip) - offset - 1;
+
This looks like an off-by-one. Do you mean the following?
if (offset + len > XFS_ISIZE(ip))
len = XFS_ISIZE(ip) - offset;
It's not an off-by-one (it's self-consistent), but your way makes more
sense, I'll fix it ;)
Thanks,
Calvin
Brian
+ /*
* Now that we've unmap all full blocks we'll have to zero out any
* partial block at the beginning and/or end. xfs_zero_range is
* smart enough to skip any holes, including those we just created.
--
2.9.3
--
To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v2] xfs: Honor FALLOC_FL_KEEP_SIZE when punching ends of files
On Sun, Mar 19, 2017 at 09:54:51PM -0700, Calvin Owens wrote:
> When punching past EOF on XFS, fallocate(mode=PUNCH_HOLE|KEEP_SIZE) will
> round the file size up to the nearest multiple of PAGE_SIZE:
>
> calvinow@vm-disks/generic-xfs-1 ~$ dd if=/dev/urandom of=test bs=2048
> count=1
> calvinow@vm-disks/generic-xfs-1 ~$ stat test
> Size: 2048Blocks: 8 IO Block: 4096 regular file
> calvinow@vm-disks/generic-xfs-1 ~$ fallocate -n -l 2048 -o 2048 -p test
> calvinow@vm-disks/generic-xfs-1 ~$ stat test
> Size: 4096Blocks: 8 IO Block: 4096 regular file
>
> Commit 3c2bdc912a1cc050 ("xfs: kill xfs_zero_remaining_bytes") replaced
> xfs_zero_remaining_bytes() with calls to iomap helpers. The new helpers
> don't enforce that [pos,offset) lies strictly on [0,i_size) when being
> called from xfs_free_file_space(), so by "leaking" these ranges into
> xfs_zero_range() we get this buggy behavior.
>
> Fix this by reintroducing the checks xfs_zero_remaining_bytes() did
> against i_size at the bottom of xfs_free_file_space().
>
> Reported-by: Aaron Gao
> Fixes: 3c2bdc912a1cc050 ("xfs: kill xfs_zero_remaining_bytes")
> Cc: Christoph Hellwig
> Cc: # 4.8+
> Signed-off-by: Calvin Owens
> ---
> fs/xfs/xfs_bmap_util.c | 11 +++
> 1 file changed, 11 insertions(+)
>
> diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
> index 8b75dce..0796ebc 100644
> --- a/fs/xfs/xfs_bmap_util.c
> +++ b/fs/xfs/xfs_bmap_util.c
> @@ -1309,6 +1309,17 @@ xfs_free_file_space(
> }
>
> /*
> + * Avoid doing I/O beyond eof - it's not necessary
> + * since nothing can read beyond eof. The space will
> + * be zeroed when the file is extended anyway.
> + */
I'd suggest to update the comment below with this information and move
the following bits down below it as well.
> + if (offset >= XFS_ISIZE(ip))
> + return 0;
> +
> + if ((offset + len) >= XFS_ISIZE(ip))
> + len = XFS_ISIZE(ip) - offset - 1;
> +
This looks like an off-by-one. Do you mean the following?
if (offset + len > XFS_ISIZE(ip))
len = XFS_ISIZE(ip) - offset;
Brian
> + /*
>* Now that we've unmap all full blocks we'll have to zero out any
>* partial block at the beginning and/or end. xfs_zero_range is
>* smart enough to skip any holes, including those we just created.
> --
> 2.9.3
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
> the body of a message to majord...@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v2] xfs: Honor FALLOC_FL_KEEP_SIZE when punching ends of files
On Sun, Mar 19, 2017 at 09:54:51PM -0700, Calvin Owens wrote:
> When punching past EOF on XFS, fallocate(mode=PUNCH_HOLE|KEEP_SIZE) will
> round the file size up to the nearest multiple of PAGE_SIZE:
>
> calvinow@vm-disks/generic-xfs-1 ~$ dd if=/dev/urandom of=test bs=2048
> count=1
> calvinow@vm-disks/generic-xfs-1 ~$ stat test
> Size: 2048Blocks: 8 IO Block: 4096 regular file
> calvinow@vm-disks/generic-xfs-1 ~$ fallocate -n -l 2048 -o 2048 -p test
> calvinow@vm-disks/generic-xfs-1 ~$ stat test
> Size: 4096Blocks: 8 IO Block: 4096 regular file
>
> Commit 3c2bdc912a1cc050 ("xfs: kill xfs_zero_remaining_bytes") replaced
> xfs_zero_remaining_bytes() with calls to iomap helpers. The new helpers
> don't enforce that [pos,offset) lies strictly on [0,i_size) when being
> called from xfs_free_file_space(), so by "leaking" these ranges into
> xfs_zero_range() we get this buggy behavior.
>
> Fix this by reintroducing the checks xfs_zero_remaining_bytes() did
> against i_size at the bottom of xfs_free_file_space().
>
> Reported-by: Aaron Gao
> Fixes: 3c2bdc912a1cc050 ("xfs: kill xfs_zero_remaining_bytes")
> Cc: Christoph Hellwig
> Cc: # 4.8+
> Signed-off-by: Calvin Owens
> ---
> fs/xfs/xfs_bmap_util.c | 11 +++
> 1 file changed, 11 insertions(+)
>
> diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
> index 8b75dce..0796ebc 100644
> --- a/fs/xfs/xfs_bmap_util.c
> +++ b/fs/xfs/xfs_bmap_util.c
> @@ -1309,6 +1309,17 @@ xfs_free_file_space(
> }
>
> /*
> + * Avoid doing I/O beyond eof - it's not necessary
> + * since nothing can read beyond eof. The space will
> + * be zeroed when the file is extended anyway.
> + */
I'd suggest to update the comment below with this information and move
the following bits down below it as well.
> + if (offset >= XFS_ISIZE(ip))
> + return 0;
> +
> + if ((offset + len) >= XFS_ISIZE(ip))
> + len = XFS_ISIZE(ip) - offset - 1;
> +
This looks like an off-by-one. Do you mean the following?
if (offset + len > XFS_ISIZE(ip))
len = XFS_ISIZE(ip) - offset;
Brian
> + /*
>* Now that we've unmap all full blocks we'll have to zero out any
>* partial block at the beginning and/or end. xfs_zero_range is
>* smart enough to skip any holes, including those we just created.
> --
> 2.9.3
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
> the body of a message to majord...@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
[PATCH v2] xfs: Honor FALLOC_FL_KEEP_SIZE when punching ends of files
When punching past EOF on XFS, fallocate(mode=PUNCH_HOLE|KEEP_SIZE) will
round the file size up to the nearest multiple of PAGE_SIZE:
calvinow@vm-disks/generic-xfs-1 ~$ dd if=/dev/urandom of=test bs=2048 count=1
calvinow@vm-disks/generic-xfs-1 ~$ stat test
Size: 2048Blocks: 8 IO Block: 4096 regular file
calvinow@vm-disks/generic-xfs-1 ~$ fallocate -n -l 2048 -o 2048 -p test
calvinow@vm-disks/generic-xfs-1 ~$ stat test
Size: 4096Blocks: 8 IO Block: 4096 regular file
Commit 3c2bdc912a1cc050 ("xfs: kill xfs_zero_remaining_bytes") replaced
xfs_zero_remaining_bytes() with calls to iomap helpers. The new helpers
don't enforce that [pos,offset) lies strictly on [0,i_size) when being
called from xfs_free_file_space(), so by "leaking" these ranges into
xfs_zero_range() we get this buggy behavior.
Fix this by reintroducing the checks xfs_zero_remaining_bytes() did
against i_size at the bottom of xfs_free_file_space().
Reported-by: Aaron Gao
Fixes: 3c2bdc912a1cc050 ("xfs: kill xfs_zero_remaining_bytes")
Cc: Christoph Hellwig
Cc: # 4.8+
Signed-off-by: Calvin Owens
---
fs/xfs/xfs_bmap_util.c | 11 +++
1 file changed, 11 insertions(+)
diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index 8b75dce..0796ebc 100644
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -1309,6 +1309,17 @@ xfs_free_file_space(
}
/*
+* Avoid doing I/O beyond eof - it's not necessary
+* since nothing can read beyond eof. The space will
+* be zeroed when the file is extended anyway.
+*/
+ if (offset >= XFS_ISIZE(ip))
+ return 0;
+
+ if ((offset + len) >= XFS_ISIZE(ip))
+ len = XFS_ISIZE(ip) - offset - 1;
+
+ /*
* Now that we've unmap all full blocks we'll have to zero out any
* partial block at the beginning and/or end. xfs_zero_range is
* smart enough to skip any holes, including those we just created.
--
2.9.3
[PATCH v2] xfs: Honor FALLOC_FL_KEEP_SIZE when punching ends of files
When punching past EOF on XFS, fallocate(mode=PUNCH_HOLE|KEEP_SIZE) will
round the file size up to the nearest multiple of PAGE_SIZE:
calvinow@vm-disks/generic-xfs-1 ~$ dd if=/dev/urandom of=test bs=2048 count=1
calvinow@vm-disks/generic-xfs-1 ~$ stat test
Size: 2048Blocks: 8 IO Block: 4096 regular file
calvinow@vm-disks/generic-xfs-1 ~$ fallocate -n -l 2048 -o 2048 -p test
calvinow@vm-disks/generic-xfs-1 ~$ stat test
Size: 4096Blocks: 8 IO Block: 4096 regular file
Commit 3c2bdc912a1cc050 ("xfs: kill xfs_zero_remaining_bytes") replaced
xfs_zero_remaining_bytes() with calls to iomap helpers. The new helpers
don't enforce that [pos,offset) lies strictly on [0,i_size) when being
called from xfs_free_file_space(), so by "leaking" these ranges into
xfs_zero_range() we get this buggy behavior.
Fix this by reintroducing the checks xfs_zero_remaining_bytes() did
against i_size at the bottom of xfs_free_file_space().
Reported-by: Aaron Gao
Fixes: 3c2bdc912a1cc050 ("xfs: kill xfs_zero_remaining_bytes")
Cc: Christoph Hellwig
Cc: # 4.8+
Signed-off-by: Calvin Owens
---
fs/xfs/xfs_bmap_util.c | 11 +++
1 file changed, 11 insertions(+)
diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index 8b75dce..0796ebc 100644
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -1309,6 +1309,17 @@ xfs_free_file_space(
}
/*
+* Avoid doing I/O beyond eof - it's not necessary
+* since nothing can read beyond eof. The space will
+* be zeroed when the file is extended anyway.
+*/
+ if (offset >= XFS_ISIZE(ip))
+ return 0;
+
+ if ((offset + len) >= XFS_ISIZE(ip))
+ len = XFS_ISIZE(ip) - offset - 1;
+
+ /*
* Now that we've unmap all full blocks we'll have to zero out any
* partial block at the beginning and/or end. xfs_zero_range is
* smart enough to skip any holes, including those we just created.
--
2.9.3
