Messages in this thread | | | Date | Mon, 01 Dec 2008 16:00:54 -0500 | From | Oren Laadan <> | Subject | Re: [RFC v10][PATCH 09/13] Restore open file descriprtors |
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Dave Hansen wrote: > On Mon, 2008-12-01 at 15:41 -0500, Oren Laadan wrote: >>>>> + fd = cr_attach_file(file); /* no need to cleanup 'file' below */ >>>>> + if (fd < 0) { >>>>> + filp_close(file, NULL); >>>>> + ret = fd; >>>>> + goto out; >>>>> + } >>>>> + >>>>> + /* register new <objref, file> tuple in hash table */ >>>>> + ret = cr_obj_add_ref(ctx, file, parent, CR_OBJ_FILE, 0); >>>>> + if (ret < 0) >>>>> + goto out; >>>> Who said that file still exists at that point? >> Correct. This call should move higher up befor ethe call to cr_attach_file() > > Is that sufficient? It seems like we're depending on the fd's reference > to the 'struct file' to keep it valid in the hash. If something happens > to the fd (like the other thread messing with it) the 'struct file' can > still go away. > > Shouldn't we do another get_file() for the hash's reference?
When a shared object is inserted to the hash we automatically take another reference to it (according to its type) for as long as it remains in the hash. See: 'cr_obj_ref_grab()' and 'cr_obj_ref_drop()'. So by moving that call higher up, we protect the struct file.
Oren.
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