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authorMiklos Szeredi <mszeredi@suse.cz>2015-01-06 12:45:35 +0300
committerMiklos Szeredi <mszeredi@suse.cz>2015-01-06 12:45:35 +0300
commit21f621741a770c119e7529a3f5c0e6b7c91383a3 (patch)
tree4393194807e351d0c2922673d44409a656a87259 /fs/fuse/dev.c
parentb1940cd21c0f4abdce101253e860feff547291b0 (diff)
downloadlinux-21f621741a770c119e7529a3f5c0e6b7c91383a3.tar.xz
fuse: fix LOOKUP vs INIT compat handling
Analysis from Marc: "Commit 7078187a795f ("fuse: introduce fuse_simple_request() helper") from the above pull request triggers some EIO errors for me in some tests that rely on fuse Looking at the code changes and a bit of debugging info I think there's a general problem here that fuse_get_req checks and possibly waits for fc->initialized, and this was always called first. But this commit changes the ordering and in many places fc->minor is now possibly used before fuse_get_req, and we can't be sure that fc has been initialized. In my case fuse_lookup_init sets req->out.args[0].size to the wrong size because fc->minor at that point is still 0, leading to the EIO error." Fix by moving the compat adjustments into fuse_simple_request() to after fuse_get_req(). This is also more readable than the original, since now compatibility is handled in a single function instead of cluttering each operation. Reported-by: Marc Dionne <marc.c.dionne@gmail.com> Tested-by: Marc Dionne <marc.c.dionne@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Fixes: 7078187a795f ("fuse: introduce fuse_simple_request() helper")
Diffstat (limited to 'fs/fuse/dev.c')
-rw-r--r--fs/fuse/dev.c36
1 files changed, 36 insertions, 0 deletions
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index ba1107977f2e..c847d6b225e2 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -511,6 +511,39 @@ void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
}
EXPORT_SYMBOL_GPL(fuse_request_send);
+static void fuse_adjust_compat(struct fuse_conn *fc, struct fuse_args *args)
+{
+ if (fc->minor < 4 && args->in.h.opcode == FUSE_STATFS)
+ args->out.args[0].size = FUSE_COMPAT_STATFS_SIZE;
+
+ if (fc->minor < 9) {
+ switch (args->in.h.opcode) {
+ case FUSE_LOOKUP:
+ case FUSE_CREATE:
+ case FUSE_MKNOD:
+ case FUSE_MKDIR:
+ case FUSE_SYMLINK:
+ case FUSE_LINK:
+ args->out.args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE;
+ break;
+ case FUSE_GETATTR:
+ case FUSE_SETATTR:
+ args->out.args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE;
+ break;
+ }
+ }
+ if (fc->minor < 12) {
+ switch (args->in.h.opcode) {
+ case FUSE_CREATE:
+ args->in.args[0].size = sizeof(struct fuse_open_in);
+ break;
+ case FUSE_MKNOD:
+ args->in.args[0].size = FUSE_COMPAT_MKNOD_IN_SIZE;
+ break;
+ }
+ }
+}
+
ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args)
{
struct fuse_req *req;
@@ -520,6 +553,9 @@ ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args)
if (IS_ERR(req))
return PTR_ERR(req);
+ /* Needs to be done after fuse_get_req() so that fc->minor is valid */
+ fuse_adjust_compat(fc, args);
+
req->in.h.opcode = args->in.h.opcode;
req->in.h.nodeid = args->in.h.nodeid;
req->in.numargs = args->in.numargs;