Commit ff002b30 authored by Jens Axboe's avatar Jens Axboe
Browse files

io_uring: grab ->fs as part of async preparation 



This passes it in to io-wq, so it assumes the right fs_struct when
executing async work that may need to do lookups.

Cc: stable@vger.kernel.org # 5.3+
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 9392a27d

fs/io_uring.c

+28 −0
Original line number Diff line number Diff line
@@ -75,6 +75,7 @@ 
#include <linux/fsnotify.h>

#include <linux/fadvise.h>

#include <linux/eventpoll.h>

#include <linux/fs_struct.h>



#define CREATE_TRACE_POINTS

#include <trace/events/io_uring.h>
@@ -611,6 +612,8 @@ struct io_op_def { 
	unsigned		not_supported : 1;

	/* needs file table */

	unsigned		file_table : 1;

	/* needs ->fs */

	unsigned		needs_fs : 1;

};



static const struct io_op_def io_op_defs[] = {
@@ -653,12 +656,14 @@ static const struct io_op_def io_op_defs[] = { 
		.needs_mm		= 1,

		.needs_file		= 1,

		.unbound_nonreg_file	= 1,

		.needs_fs		= 1,

	},

	[IORING_OP_RECVMSG] = {

		.async_ctx		= 1,

		.needs_mm		= 1,

		.needs_file		= 1,

		.unbound_nonreg_file	= 1,

		.needs_fs		= 1,

	},

	[IORING_OP_TIMEOUT] = {

		.async_ctx		= 1,
@@ -689,6 +694,7 @@ static const struct io_op_def io_op_defs[] = { 
		.needs_file		= 1,

		.fd_non_neg		= 1,

		.file_table		= 1,

		.needs_fs		= 1,

	},

	[IORING_OP_CLOSE] = {

		.needs_file		= 1,
@@ -702,6 +708,7 @@ static const struct io_op_def io_op_defs[] = { 
		.needs_mm		= 1,

		.needs_file		= 1,

		.fd_non_neg		= 1,

		.needs_fs		= 1,

	},

	[IORING_OP_READ] = {

		.needs_mm		= 1,
@@ -733,6 +740,7 @@ static const struct io_op_def io_op_defs[] = { 
		.needs_file		= 1,

		.fd_non_neg		= 1,

		.file_table		= 1,

		.needs_fs		= 1,

	},

	[IORING_OP_EPOLL_CTL] = {

		.unbound_nonreg_file	= 1,
@@ -907,6 +915,16 @@ static inline void io_req_work_grab_env(struct io_kiocb *req, 
	}

	if (!req->work.creds)

		req->work.creds = get_current_cred();

	if (!req->work.fs && def->needs_fs) {

		spin_lock(&current->fs->lock);

		if (!current->fs->in_exec) {

			req->work.fs = current->fs;

			req->work.fs->users++;

		} else {

			req->work.flags |= IO_WQ_WORK_CANCEL;

		}

		spin_unlock(&current->fs->lock);

	}

}



static inline void io_req_work_drop_env(struct io_kiocb *req)
@@ -919,6 +937,16 @@ static inline void io_req_work_drop_env(struct io_kiocb *req) 
		put_cred(req->work.creds);

		req->work.creds = NULL;

	}

	if (req->work.fs) {

		struct fs_struct *fs = req->work.fs;



		spin_lock(&req->work.fs->lock);

		if (--fs->users)

			fs = NULL;

		spin_unlock(&req->work.fs->lock);

		if (fs)

			free_fs_struct(fs);

	}

}



static inline bool io_prep_async_work(struct io_kiocb *req,

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