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kernfs: fix regression in kernfs_fop_write caused by wrong type

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commit ba87977a49913129962af8ac35b0e13e0fa4382d upstream.

Commit b7ce40cff0 ("kernfs: cache atomic_write_len in
kernfs_open_file") changes type of local variable 'len' from ssize_t
to size_t. This change caused that the *ppos value is updated also
when the previous write callback failed.

Mentioned snippet:
...
len = ops->write(...); <- return value can be negative
...
if (len > 0)           <- true here in this case
        *ppos += len;
...

Fixes: b7ce40cff0 ("kernfs: cache atomic_write_len in kernfs_open_file")
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ivan Vecera <ivecera@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ivan Vecera 2018-01-19 09:18:54 +01:00 • committed by Greg Kroah-Hartman
parent fb8b16859a
commit f1db1b8055
1 changed files with 1 additions and 1 deletions
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2
fs/kernfs/file.c
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@ -272,7 +272,7 @@ static ssize_t kernfs_fop_write(struct file *file, const char __user *user_buf,
{ {
struct kernfs_open_file *of = kernfs_of(file); struct kernfs_open_file *of = kernfs_of(file);
const struct kernfs_ops *ops; const struct kernfs_ops *ops;
size_t len; ssize_t len;
char *buf; char *buf;
if (of->atomic_write_len) { if (of->atomic_write_len) {