6.6-stable review patch. If anyone has any objections, please let me know.
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From: Amir Goldstein amir73il@gmail.com
[ Upstream commit 6ae654392bb516a0baa47fed1f085d84e8cad739 ]
In vfs code, sb_start_write() is usually called after the permission hook in rw_verify_area(). vfs_iocb_iter_write() is an exception to this rule, where kiocb_start_write() is called by its callers.
Move kiocb_start_write() from the callers into vfs_iocb_iter_write() after the rw_verify_area() checks, to make them "start-write-safe".
The semantics of vfs_iocb_iter_write() is changed, so that the caller is responsible for calling kiocb_end_write() on completion only if async iocb was queued. The completion handlers of both callers were adapted to this semantic change.
This is needed for fanotify "pre content" events.
Suggested-by: Jan Kara jack@suse.cz Suggested-by: Josef Bacik josef@toxicpanda.com Signed-off-by: Amir Goldstein amir73il@gmail.com Link: https://lore.kernel.org/r/20231122122715.2561213-14-amir73il@gmail.com Reviewed-by: Josef Bacik josef@toxicpanda.com Reviewed-by: Jan Kara jack@suse.cz Signed-off-by: Christian Brauner brauner@kernel.org Stable-dep-of: 7c98f7cb8fda ("remove call_{read,write}_iter() functions") Signed-off-by: Sasha Levin sashal@kernel.org --- fs/cachefiles/io.c | 5 ++--- fs/overlayfs/file.c | 8 ++++---- fs/read_write.c | 7 +++++++ 3 files changed, 13 insertions(+), 7 deletions(-)
diff --git a/fs/cachefiles/io.c b/fs/cachefiles/io.c index 009d23cd435b5..5857241c59181 100644 --- a/fs/cachefiles/io.c +++ b/fs/cachefiles/io.c @@ -259,7 +259,8 @@ static void cachefiles_write_complete(struct kiocb *iocb, long ret)
_enter("%ld", ret);
- kiocb_end_write(iocb); + if (ki->was_async) + kiocb_end_write(iocb);
if (ret < 0) trace_cachefiles_io_error(object, inode, ret, @@ -319,8 +320,6 @@ int __cachefiles_write(struct cachefiles_object *object, ki->iocb.ki_complete = cachefiles_write_complete; atomic_long_add(ki->b_writing, &cache->b_writing);
- kiocb_start_write(&ki->iocb); - get_file(ki->iocb.ki_filp); cachefiles_grab_object(object, cachefiles_obj_get_ioreq);
diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c index 9fd88579bfbfb..a1c64c2b8e204 100644 --- a/fs/overlayfs/file.c +++ b/fs/overlayfs/file.c @@ -295,10 +295,8 @@ static void ovl_aio_cleanup_handler(struct ovl_aio_req *aio_req) struct kiocb *iocb = &aio_req->iocb; struct kiocb *orig_iocb = aio_req->orig_iocb;
- if (iocb->ki_flags & IOCB_WRITE) { - kiocb_end_write(iocb); + if (iocb->ki_flags & IOCB_WRITE) ovl_file_modified(orig_iocb->ki_filp); - }
orig_iocb->ki_pos = iocb->ki_pos; ovl_aio_put(aio_req); @@ -310,6 +308,9 @@ static void ovl_aio_rw_complete(struct kiocb *iocb, long res) struct ovl_aio_req, iocb); struct kiocb *orig_iocb = aio_req->orig_iocb;
+ if (iocb->ki_flags & IOCB_WRITE) + kiocb_end_write(iocb); + ovl_aio_cleanup_handler(aio_req); orig_iocb->ki_complete(orig_iocb, res); } @@ -421,7 +422,6 @@ static ssize_t ovl_write_iter(struct kiocb *iocb, struct iov_iter *iter) aio_req->iocb.ki_flags = ifl; aio_req->iocb.ki_complete = ovl_aio_rw_complete; refcount_set(&aio_req->ref, 2); - kiocb_start_write(&aio_req->iocb); ret = vfs_iocb_iter_write(real.file, &aio_req->iocb, iter); ovl_aio_put(aio_req); if (ret != -EIOCBQUEUED) diff --git a/fs/read_write.c b/fs/read_write.c index 4771701c896ba..9a56949f3b8d1 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -865,6 +865,10 @@ static ssize_t do_iter_write(struct file *file, struct iov_iter *iter, return ret; }
+/* + * Caller is responsible for calling kiocb_end_write() on completion + * if async iocb was queued. + */ ssize_t vfs_iocb_iter_write(struct file *file, struct kiocb *iocb, struct iov_iter *iter) { @@ -885,7 +889,10 @@ ssize_t vfs_iocb_iter_write(struct file *file, struct kiocb *iocb, if (ret < 0) return ret;
+ kiocb_start_write(iocb); ret = call_write_iter(file, iocb, iter); + if (ret != -EIOCBQUEUED) + kiocb_end_write(iocb); if (ret > 0) fsnotify_modify(file);