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| author | Christian Brauner <brauner@kernel.org> | 2024-09-08 08:58:01 +0200 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2024-09-12 11:58:46 +0200 |
| commit | 24a988f75c8a5f16ef935c51039700e985767eb9 (patch) | |
| tree | d071e54a8009b45461848dc550e0ee4800297b92 /fs/pipe.c | |
| parent | 0f389adb4b80eef29920db2e2c99392aa5d06811 (diff) | |
| parent | 11068e0b64cbb540b96e577fcca0926242ecaf58 (diff) | |
| download | linux-24a988f75c8a5f16ef935c51039700e985767eb9.tar.gz | |
Merge patch series "file: remove f_version"
Christian Brauner <brauner@kernel.org> says:
The f_version member in struct file isn't particularly well-defined. It
is mainly used as a cookie to detect concurrent seeks when iterating
directories. But it is also abused by some subsystems for completely
unrelated things.
It is mostly a directory specific thing that doesn't really need to live
in struct file and with its wonky semantics it really lacks a specific
function.
For pipes, f_version is (ab)used to defer poll notifications until a
write has happened. And struct pipe_inode_info is used by multiple
struct files in their ->private_data so there's no chance of pushing
that down into file->private_data without introducing another pointer
indirection.
But this should be a solvable problem. Only regular files with
FMODE_ATOMIC_POS and directories require f_pos_lock. Pipes and other
files don't. So this adds a union into struct file encompassing
f_pos_lock and a pipe specific f_pipe member that pipes can use. This
union of course can be extended to other file types and is similar to
what we do in struct inode already.
* patches from https://lore.kernel.org/r/20240830-vfs-file-f_version-v1-0-6d3e4816aa7b@kernel.org:
fs: remove f_version
pipe: use f_pipe
fs: add f_pipe
ubifs: store cookie in private data
ufs: store cookie in private data
udf: store cookie in private data
proc: store cookie in private data
ocfs2: store cookie in private data
input: remove f_version abuse
ext4: store cookie in private data
ext2: store cookie in private data
affs: store cookie in private data
fs: add generic_llseek_cookie()
fs: use must_set_pos()
fs: add must_set_pos()
fs: add vfs_setpos_cookie()
s390: remove unused f_version
ceph: remove unused f_version
adi: remove unused f_version
file: remove pointless comment
Link: https://lore.kernel.org/r/20240830-vfs-file-f_version-v1-0-6d3e4816aa7b@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Diffstat (limited to 'fs/pipe.c')
| -rw-r--r-- | fs/pipe.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/fs/pipe.c b/fs/pipe.c index 7dff2aa50a6ddb..d3735f1d6f000d 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -686,7 +686,7 @@ pipe_poll(struct file *filp, poll_table *wait) if (filp->f_mode & FMODE_READ) { if (!pipe_empty(head, tail)) mask |= EPOLLIN | EPOLLRDNORM; - if (!pipe->writers && filp->f_version != pipe->w_counter) + if (!pipe->writers && filp->f_pipe != pipe->w_counter) mask |= EPOLLHUP; } @@ -945,6 +945,7 @@ int create_pipe_files(struct file **res, int flags) } f->private_data = inode->i_pipe; + f->f_pipe = 0; res[0] = alloc_file_clone(f, O_RDONLY | (flags & O_NONBLOCK), &pipefifo_fops); @@ -954,6 +955,7 @@ int create_pipe_files(struct file **res, int flags) return PTR_ERR(res[0]); } res[0]->private_data = inode->i_pipe; + res[0]->f_pipe = 0; res[1] = f; stream_open(inode, res[0]); stream_open(inode, res[1]); @@ -1108,7 +1110,7 @@ static int fifo_open(struct inode *inode, struct file *filp) bool is_pipe = inode->i_sb->s_magic == PIPEFS_MAGIC; int ret; - filp->f_version = 0; + filp->f_pipe = 0; spin_lock(&inode->i_lock); if (inode->i_pipe) { @@ -1155,7 +1157,7 @@ static int fifo_open(struct inode *inode, struct file *filp) if ((filp->f_flags & O_NONBLOCK)) { /* suppress EPOLLHUP until we have * seen a writer */ - filp->f_version = pipe->w_counter; + filp->f_pipe = pipe->w_counter; } else { if (wait_for_partner(pipe, &pipe->w_counter)) goto err_rd; |