From: "Jason A. Donenfeld" <Jason@xxxxxxxxx> 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@xxxxxxxxx> Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx> (cherry picked from commit e7478158e1378325907edfdd960eca98a1be405b) Conflicts: fs/open.c Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Saeed Mirzamohammadi <saeed.mirzamohammadi@xxxxxxxxxx> --- fs/file_table.c | 2 ++ fs/open.c | 4 ++++ 2 files changed, 6 insertions(+) diff --git a/fs/file_table.c b/fs/file_table.c index e8c9016703ad..f675817be4ad 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -198,6 +198,8 @@ static struct file *alloc_file(const struct path *path, int flags, file->f_mapping = path->dentry->d_inode->i_mapping; file->f_wb_err = filemap_sample_wb_err(file->f_mapping); file->f_sb_err = file_sample_sb_err(file); + if (fop->llseek && fop->llseek != no_llseek) + file->f_mode |= FMODE_LSEEK; if ((file->f_mode & FMODE_READ) && likely(fop->read || fop->read_iter)) file->f_mode |= FMODE_CAN_READ; diff --git a/fs/open.c b/fs/open.c index 1ba1d2ab2ef0..38bf38d41418 100644 --- a/fs/open.c +++ b/fs/open.c @@ -834,6 +834,10 @@ 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; f->f_write_hint = WRITE_LIFE_NOT_SET; f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC); -- 2.31.1
