| Message ID | OFB615AF11.05DABF7D-ONC1257A8D.00661C69-C1257A8D.0066832C@transmode.se |
|---|---|
| State | New, archived |
| Headers | show |
> > Thomas.Betker@rohde-schwarz.com wrote on 2012/10/04 18:51:58: > > > > Hello Joakim: > > > > > Try Reply With Internet-style History (We use Notes here too) > > > > Got it. Thanks! > > > > > > jffs2_reserve_space() must not be called with f->sem held because it > > > > acquires c->alloc_sem. > > > > > > hmm, are you sure? Did it fail? > > > As far as I can see jffs2_garbage_collect_live() does this. > > > > jffs2_reserve_space() does mutex_lock(&c->alloc_sem) first thing, and > > README.Locking says "Never attempt to allocate space or lock alloc_sem > > with any f->sem held.". So I didn't even try; yes, I am a coward. (:-) > > Also, all the code I checked carefully releases f->sem before calling > > jffs2_reserve_space(). > > I see, thanks. > > > > > jffs2_garbage_collect_live() doesn't call jffs2_reserve_space() directly. > > Is it called indirectly somehow? > > hmm, misread the code a bit so forget this comment. > > > > > > > So I have moved mutex_lock(&f->sem) and grab_cache_page_write_begin() > > > > after jffs2_reserve_space(). Attached is my 3.4.11 patch (which is > > based > > > > on your patch) for review; I hope it is not mangled by Lotus Notes ... > > > > > > don't have time to look ATM > > > > Okay. When the tests succeed, I will simply mail it to the list as a > > regular patch, for general review. > > I think your patch will work, but I don't like having 2 call sites > to grab_cache_page_write_begin(mapping, index, flags) so I came > up with this instead(untested as well): Forgot, could you add some debug code to test if pageofs <= inode->i_size: ri.isize = cpu_to_je32(max((uint32_t)inode->i_size, pageofs)); .... if(pageofs <= inode->i_size) { print debug stuff here } ri.dsize = cpu_to_je32(pageofs - inode->i_size); Jocke
Hello Joakim: > I think your patch will work, but I don't like having 2 call sites > to grab_cache_page_write_begin(mapping, index, flags) so I came > up with this instead(untested as well): The tests I ran this night were successful. I have adapted my patch according to your suggestions and started re-testing; I won't be able to finish today, though, so I will post the final patch on Monday (assuming that it works). Have a nice weekend, Thomas
Thomas.Betker@rohde-schwarz.com wrote on 2012/10/05 11:17:22: > > Hello Joakim: > > > I think your patch will work, but I don't like having 2 call sites > > to grab_cache_page_write_begin(mapping, index, flags) so I came > > up with this instead(untested as well): > > The tests I ran this night were successful. I have adapted my patch > according to your suggestions and started re-testing; I won't be able to > finish today, though, so I will post the final patch on Monday (assuming > that it works). I was just about to sent the final version. There was an bug in the error patch. Hang in and a proper patch will come shortly. Jocke
diff --git a/fs/jffs2/file.c b/fs/jffs2/file.c index db3889b..8eaeaa35 100644 --- a/fs/jffs2/file.c +++ b/fs/jffs2/file.c @@ -140,31 +140,33 @@ static int jffs2_write_begin(struct file *filp, struct address_space *mapping, struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode); pgoff_t index = pos >> PAGE_CACHE_SHIFT; uint32_t pageofs = index << PAGE_CACHE_SHIFT; - int ret = 0; + int ret = -ENOMEM; + struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb); + struct jffs2_raw_inode ri; + uint32_t alloc_len; + + if (pageofs > inode->i_size) { + ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len, + ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE); + if (ret) + return ret; + } + mutex_lock(&f->sem); pg = grab_cache_page_write_begin(mapping, index, flags); if (!pg) - return -ENOMEM; + goto out_unlock; *pagep = pg; jffs2_dbg(1, "%s()\n", __func__); - if (pageofs > inode->i_size) { + if (!ret) { /* reserve_space succeded */ /* Make new hole frag from old EOF to new page */ - struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb); - struct jffs2_raw_inode ri; struct jffs2_full_dnode *fn; - uint32_t alloc_len; jffs2_dbg(1, "Writing new hole frag 0x%x-0x%x between current EOF and new page\n", (unsigned int)inode->i_size, pageofs); - ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len, - ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE); - if (ret) - goto out_page; - - mutex_lock(&f->sem); memset(&ri, 0, sizeof(ri)); ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK); @@ -191,7 +193,6 @@ static int jffs2_write_begin(struct file *filp, struct address_space *mapping, if (IS_ERR(fn)) { ret = PTR_ERR(fn); jffs2_complete_reservation(c); - mutex_unlock(&f->sem); goto out_page; } ret = jffs2_add_full_dnode_to_inode(c, f, fn); @@ -206,12 +207,10 @@ static int jffs2_write_begin(struct file *filp, struct address_space *mapping, jffs2_mark_node_obsolete(c, fn->raw); jffs2_free_full_dnode(fn); jffs2_complete_reservation(c); - mutex_unlock(&f->sem); goto out_page; } jffs2_complete_reservation(c); inode->i_size = pageofs; - mutex_unlock(&f->sem); } /* @@ -220,18 +219,19 @@ static int jffs2_write_begin(struct file *filp, struct address_space *mapping, * case of a short-copy. */ if (!PageUptodate(pg)) { - mutex_lock(&f->sem); ret = jffs2_do_readpage_nolock(inode, pg); - mutex_unlock(&f->sem); if (ret) goto out_page; } + mutex_unlock(&f->sem); jffs2_dbg(1, "end write_begin(). pg->flags %lx\n", pg->flags); - return ret; + return 0; out_page: unlock_page(pg); page_cache_release(pg); +out_unlock: + mutex_unlock(&f->sem); return ret; }