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authorJason A. Donenfeld <Jason@zx2c4.com>2022-06-29 15:06:57 +0200
committerAl Viro <viro@zeniv.linux.org.uk>2022-07-16 09:18:56 -0400
commite7478158e1378325907edfdd960eca98a1be405b (patch)
tree69d1ab990e63cf106b1a81fede39cef603991a5c /fs/open.c
parentb13baccc3850ca8b8cccbf8ed9912dbaa0fdf7f3 (diff)
fs: clear or set FMODE_LSEEK based on llseek function
Pipe-like behaviour on llseek(2) (i.e. unconditionally failing with -ESPIPE) can be expresses in 3 ways: 1) ->llseek set to NULL in file_operations 2) ->llseek set to no_llseek in file_operations 3) FMODE_LSEEK *not* set in ->f_mode. Enforce (3) in cases (1) and (2); that will allow to simplify the checks and eventually get rid of no_llseek boilerplate. Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/open.c')
-rw-r--r--fs/open.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/fs/open.c b/fs/open.c
index 1d57fbde2feb..4488bd77c390 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -858,6 +858,10 @@ static int do_dentry_open(struct file *f,
if ((f->f_mode & FMODE_WRITE) &&
likely(f->f_op->write || f->f_op->write_iter))
f->f_mode |= FMODE_CAN_WRITE;
+ if ((f->f_mode & FMODE_LSEEK) && !f->f_op->llseek)
+ f->f_mode &= ~FMODE_LSEEK;
+ if ((f->f_mode & FMODE_LSEEK) && f->f_op->llseek == no_llseek)
+ f->f_mode &= ~FMODE_LSEEK;
if (f->f_mapping->a_ops && f->f_mapping->a_ops->direct_IO)
f->f_mode |= FMODE_CAN_ODIRECT;