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fuse: add reference counting to fuse_file
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Make lifetime of 'struct fuse_file' independent from 'struct file' by adding a
reference counter and destructor.

This will enable asynchronous page writeback, where it cannot be guaranteed,
that the file is not released while a request with this file handle is being
served.

The actual RELEASE request is only sent when there are no more references to
the fuse_file.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Miklos Szeredi authored and Linus Torvalds committed Oct 17, 2007
1 parent de5e3de commit c756e0a
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Showing 4 changed files with 59 additions and 42 deletions.
2 changes: 0 additions & 2 deletions fs/fuse/dev.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -233,8 +233,6 @@ static void request_end(struct fuse_conn *fc, struct fuse_req *req)
spin_unlock(&fc->lock);
dput(req->dentry);
mntput(req->vfsmount);
if (req->file)
fput(req->file);
wake_up(&req->waitq);
if (end)
end(fc, req);
Expand Down
14 changes: 7 additions & 7 deletions fs/fuse/dir.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -288,12 +288,11 @@ static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry,
static void fuse_sync_release(struct fuse_conn *fc, struct fuse_file *ff,
u64 nodeid, int flags)
{
struct fuse_req *req;

req = fuse_release_fill(ff, nodeid, flags, FUSE_RELEASE);
req->force = 1;
request_send(fc, req);
fuse_put_request(fc, req);
fuse_release_fill(ff, nodeid, flags, FUSE_RELEASE);
ff->reserved_req->force = 1;
request_send(fc, ff->reserved_req);
fuse_put_request(fc, ff->reserved_req);
kfree(ff);
}

/*
Expand Down Expand Up @@ -859,6 +858,7 @@ static int fuse_readdir(struct file *file, void *dstbuf, filldir_t filldir)
struct page *page;
struct inode *inode = file->f_path.dentry->d_inode;
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_file *ff = file->private_data;
struct fuse_req *req;

if (is_bad_inode(inode))
Expand All @@ -875,7 +875,7 @@ static int fuse_readdir(struct file *file, void *dstbuf, filldir_t filldir)
}
req->num_pages = 1;
req->pages[0] = page;
fuse_read_fill(req, file, inode, file->f_pos, PAGE_SIZE, FUSE_READDIR);
fuse_read_fill(req, ff, inode, file->f_pos, PAGE_SIZE, FUSE_READDIR);
request_send(fc, req);
nbytes = req->out.args[0].size;
err = req->out.h.error;
Expand Down
72 changes: 44 additions & 28 deletions fs/fuse/file.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -54,6 +54,7 @@ struct fuse_file *fuse_file_alloc(void)
kfree(ff);
ff = NULL;
}
atomic_set(&ff->count, 0);
}
return ff;
}
Expand All @@ -64,6 +65,22 @@ void fuse_file_free(struct fuse_file *ff)
kfree(ff);
}

static struct fuse_file *fuse_file_get(struct fuse_file *ff)
{
atomic_inc(&ff->count);
return ff;
}

static void fuse_file_put(struct fuse_file *ff)
{
if (atomic_dec_and_test(&ff->count)) {
struct fuse_req *req = ff->reserved_req;
struct fuse_conn *fc = get_fuse_conn(req->dentry->d_inode);
request_send_background(fc, req);
kfree(ff);
}
}

void fuse_finish_open(struct inode *inode, struct file *file,
struct fuse_file *ff, struct fuse_open_out *outarg)
{
Expand All @@ -72,7 +89,7 @@ void fuse_finish_open(struct inode *inode, struct file *file,
if (!(outarg->open_flags & FOPEN_KEEP_CACHE))
invalidate_mapping_pages(inode->i_mapping, 0, -1);
ff->fh = outarg->fh;
file->private_data = ff;
file->private_data = fuse_file_get(ff);
}

int fuse_open_common(struct inode *inode, struct file *file, int isdir)
Expand Down Expand Up @@ -113,8 +130,7 @@ int fuse_open_common(struct inode *inode, struct file *file, int isdir)
return err;
}

struct fuse_req *fuse_release_fill(struct fuse_file *ff, u64 nodeid, int flags,
int opcode)
void fuse_release_fill(struct fuse_file *ff, u64 nodeid, int flags, int opcode)
{
struct fuse_req *req = ff->reserved_req;
struct fuse_release_in *inarg = &req->misc.release_in;
Expand All @@ -126,25 +142,24 @@ struct fuse_req *fuse_release_fill(struct fuse_file *ff, u64 nodeid, int flags,
req->in.numargs = 1;
req->in.args[0].size = sizeof(struct fuse_release_in);
req->in.args[0].value = inarg;
kfree(ff);

return req;
}

int fuse_release_common(struct inode *inode, struct file *file, int isdir)
{
struct fuse_file *ff = file->private_data;
if (ff) {
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_req *req;

req = fuse_release_fill(ff, get_node_id(inode), file->f_flags,
isdir ? FUSE_RELEASEDIR : FUSE_RELEASE);
fuse_release_fill(ff, get_node_id(inode), file->f_flags,
isdir ? FUSE_RELEASEDIR : FUSE_RELEASE);

/* Hold vfsmount and dentry until release is finished */
req->vfsmount = mntget(file->f_path.mnt);
req->dentry = dget(file->f_path.dentry);
request_send_background(fc, req);
ff->reserved_req->vfsmount = mntget(file->f_path.mnt);
ff->reserved_req->dentry = dget(file->f_path.dentry);
/*
* Normally this will send the RELEASE request,
* however if some asynchronous READ or WRITE requests
* are outstanding, the sending will be delayed
*/
fuse_file_put(ff);
}

/* Return value is ignored by VFS */
Expand Down Expand Up @@ -264,10 +279,9 @@ static int fuse_fsync(struct file *file, struct dentry *de, int datasync)
return fuse_fsync_common(file, de, datasync, 0);
}

void fuse_read_fill(struct fuse_req *req, struct file *file,
void fuse_read_fill(struct fuse_req *req, struct fuse_file *ff,
struct inode *inode, loff_t pos, size_t count, int opcode)
{
struct fuse_file *ff = file->private_data;
struct fuse_read_in *inarg = &req->misc.read_in;

inarg->fh = ff->fh;
Expand All @@ -288,7 +302,8 @@ static size_t fuse_send_read(struct fuse_req *req, struct file *file,
struct inode *inode, loff_t pos, size_t count)
{
struct fuse_conn *fc = get_fuse_conn(inode);
fuse_read_fill(req, file, inode, pos, count, FUSE_READ);
struct fuse_file *ff = file->private_data;
fuse_read_fill(req, ff, inode, pos, count, FUSE_READ);
request_send(fc, req);
return req->out.args[0].size;
}
Expand Down Expand Up @@ -337,20 +352,21 @@ static void fuse_readpages_end(struct fuse_conn *fc, struct fuse_req *req)
SetPageError(page);
unlock_page(page);
}
if (req->ff)
fuse_file_put(req->ff);
fuse_put_request(fc, req);
}

static void fuse_send_readpages(struct fuse_req *req, struct file *file,
static void fuse_send_readpages(struct fuse_req *req, struct fuse_file *ff,
struct inode *inode)
{
struct fuse_conn *fc = get_fuse_conn(inode);
loff_t pos = page_offset(req->pages[0]);
size_t count = req->num_pages << PAGE_CACHE_SHIFT;
req->out.page_zeroing = 1;
fuse_read_fill(req, file, inode, pos, count, FUSE_READ);
fuse_read_fill(req, ff, inode, pos, count, FUSE_READ);
if (fc->async_read) {
get_file(file);
req->file = file;
req->ff = fuse_file_get(ff);
req->end = fuse_readpages_end;
request_send_background(fc, req);
} else {
Expand All @@ -359,15 +375,15 @@ static void fuse_send_readpages(struct fuse_req *req, struct file *file,
}
}

struct fuse_readpages_data {
struct fuse_fill_data {
struct fuse_req *req;
struct file *file;
struct fuse_file *ff;
struct inode *inode;
};

static int fuse_readpages_fill(void *_data, struct page *page)
{
struct fuse_readpages_data *data = _data;
struct fuse_fill_data *data = _data;
struct fuse_req *req = data->req;
struct inode *inode = data->inode;
struct fuse_conn *fc = get_fuse_conn(inode);
Expand All @@ -376,7 +392,7 @@ static int fuse_readpages_fill(void *_data, struct page *page)
(req->num_pages == FUSE_MAX_PAGES_PER_REQ ||
(req->num_pages + 1) * PAGE_CACHE_SIZE > fc->max_read ||
req->pages[req->num_pages - 1]->index + 1 != page->index)) {
fuse_send_readpages(req, data->file, inode);
fuse_send_readpages(req, data->ff, inode);
data->req = req = fuse_get_req(fc);
if (IS_ERR(req)) {
unlock_page(page);
Expand All @@ -393,14 +409,14 @@ static int fuse_readpages(struct file *file, struct address_space *mapping,
{
struct inode *inode = mapping->host;
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_readpages_data data;
struct fuse_fill_data data;
int err;

err = -EIO;
if (is_bad_inode(inode))
goto out;

data.file = file;
data.ff = file->private_data;
data.inode = inode;
data.req = fuse_get_req(fc);
err = PTR_ERR(data.req);
Expand All @@ -410,7 +426,7 @@ static int fuse_readpages(struct file *file, struct address_space *mapping,
err = read_cache_pages(mapping, pages, fuse_readpages_fill, &data);
if (!err) {
if (data.req->num_pages)
fuse_send_readpages(data.req, file, inode);
fuse_send_readpages(data.req, data.ff, inode);
else
fuse_put_request(fc, data.req);
}
Expand Down
13 changes: 8 additions & 5 deletions fs/fuse/fuse_i.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -72,6 +72,9 @@ struct fuse_file {

/** File handle used by userspace */
u64 fh;

/** Refcount */
atomic_t count;
};

/** One input argument of a request */
Expand Down Expand Up @@ -216,7 +219,7 @@ struct fuse_req {
unsigned page_offset;

/** File used in the request (or NULL) */
struct file *file;
struct fuse_file *ff;

/** vfsmount used in release */
struct vfsmount *vfsmount;
Expand Down Expand Up @@ -420,7 +423,7 @@ void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
/**
* Initialize READ or READDIR request
*/
void fuse_read_fill(struct fuse_req *req, struct file *file,
void fuse_read_fill(struct fuse_req *req, struct fuse_file *ff,
struct inode *inode, loff_t pos, size_t count, int opcode);

/**
Expand All @@ -433,9 +436,9 @@ void fuse_file_free(struct fuse_file *ff);
void fuse_finish_open(struct inode *inode, struct file *file,
struct fuse_file *ff, struct fuse_open_out *outarg);

/** */
struct fuse_req *fuse_release_fill(struct fuse_file *ff, u64 nodeid, int flags,
int opcode);
/** Fill in ff->reserved_req with a RELEASE request */
void fuse_release_fill(struct fuse_file *ff, u64 nodeid, int flags, int opcode);

/**
* Send RELEASE or RELEASEDIR request
*/
Expand Down

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