2013-05-15 (수), 13:04 +0900, Namjae Jeon: > 2013/5/15, Jaegeuk Kim <[email protected]>: > > In get_lock_data_page, if there is a data race between get_dnode_of_data > > for > > node and grab_cache_page for data, f2fs is able to face with the following > > BUG_ON(dn.data_blkaddr == NEW_ADDR). > > > > kernel BUG at /home/zeus/f2fs_test/src/fs/f2fs/data.c:251! > > [<ffffffffa044966c>] get_lock_data_page+0x1ec/0x210 [f2fs] > > Call Trace: > > [<ffffffffa043b089>] f2fs_readdir+0x89/0x210 [f2fs] > > [<ffffffff811a0920>] ? fillonedir+0x100/0x100 > > [<ffffffff811a0920>] ? fillonedir+0x100/0x100 > > [<ffffffff811a07f8>] vfs_readdir+0xb8/0xe0 > > [<ffffffff811a0b4f>] sys_getdents+0x8f/0x110 > > [<ffffffff816d7999>] system_call_fastpath+0x16/0x1b > > > > This bug is able to be occurred when the block address of the data block is > > changed after f2fs_put_dnode(). > > In order to avoid that, this patch fixes the lock order of node and data > > blocks in which the node block lock is covered by the data block lock. > > > > Signed-off-by: Jaegeuk Kim <[email protected]> > > --- > > fs/f2fs/data.c | 17 +++++++++++------ > > 1 file changed, 11 insertions(+), 6 deletions(-) > > > > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c > > index 91ff93b..05fb5c6 100644 > > --- a/fs/f2fs/data.c > > +++ b/fs/f2fs/data.c > > @@ -233,18 +233,23 @@ struct page *get_lock_data_page(struct inode *inode, > > pgoff_t index) > > struct page *page; > > int err; > > > > +repeat: > > + page = grab_cache_page(mapping, index); > > + if (!page) > > + return ERR_PTR(-ENOMEM); > > + > > set_new_dnode(&dn, inode, NULL, NULL, 0); > > err = get_dnode_of_data(&dn, index, LOOKUP_NODE); > > - if (err) > > + if (err) { > > + f2fs_put_page(page, 1); > > return ERR_PTR(err); > > + } > > f2fs_put_dnode(&dn); > > > > - if (dn.data_blkaddr == NULL_ADDR) > > + if (dn.data_blkaddr == NULL_ADDR) { > > + f2fs_put_page(page, 1); > > return ERR_PTR(-ENOENT); > > -repeat: > > - page = grab_cache_page(mapping, index); > > - if (!page) > > - return ERR_PTR(-ENOMEM); > > + } > > > > if (PageUptodate(page)) > > return page; > Is there no need to move PageUptodate condition checking to > grab_cache_page next ?
For the data consistency, I'd like to check index in its node block prior to this. Thanks, > > Thanks. > > -- > > 1.8.1.3.566.gaa39828 > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > > the body of a message to [email protected] > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > Please read the FAQ at http://www.tux.org/lkml/ > > -- Jaegeuk Kim Samsung
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