/* perform a delayed copyup of a read-write file on a read-only branch */ static int do_delayed_copyup(struct file *file, struct dentry *parent) { int bindex, bstart, bend, err = 0; struct dentry *dentry = file->f_path.dentry; struct inode *parent_inode = parent->d_inode; bstart = fbstart(file); bend = fbend(file); BUG_ON(!S_ISREG(dentry->d_inode->i_mode)); unionfs_check_file(file); for (bindex = bstart - 1; bindex >= 0; bindex--) { if (!d_deleted(dentry)) err = copyup_file(parent_inode, file, bstart, bindex, i_size_read(dentry->d_inode)); else err = copyup_deleted_file(file, dentry, parent, bstart, bindex); /* if succeeded, set lower open-file flags and break */ if (!err) { struct file *lower_file; lower_file = unionfs_lower_file_idx(file, bindex); lower_file->f_flags = file->f_flags; break; } } if (err || (bstart <= fbstart(file))) goto out; bend = fbend(file); for (bindex = bstart; bindex <= bend; bindex++) { if (unionfs_lower_file_idx(file, bindex)) { branchput(dentry->d_sb, bindex); fput(unionfs_lower_file_idx(file, bindex)); unionfs_set_lower_file_idx(file, bindex, NULL); } } path_put_lowers(dentry, bstart, bend, false); iput_lowers(dentry->d_inode, bstart, bend, false); /* for reg file, we only open it "once" */ fbend(file) = fbstart(file); dbend(dentry) = dbstart(dentry); ibend(dentry->d_inode) = ibstart(dentry->d_inode); out: unionfs_check_file(file); return err; }
int unionfs_fsync(struct file *file, struct dentry *dentry, int datasync) { int bindex, bstart, bend; struct file *lower_file; struct dentry *lower_dentry; struct dentry *parent; struct inode *lower_inode, *inode; int err = -EINVAL; unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT); parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT); unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD); err = unionfs_file_revalidate(file, parent, true); if (unlikely(err)) goto out; unionfs_check_file(file); bstart = fbstart(file); bend = fbend(file); if (bstart < 0 || bend < 0) goto out; inode = dentry->d_inode; if (unlikely(!inode)) { printk(KERN_ERR "unionfs: null lower inode in unionfs_fsync\n"); goto out; } for (bindex = bstart; bindex <= bend; bindex++) { lower_inode = unionfs_lower_inode_idx(inode, bindex); if (!lower_inode || !lower_inode->i_fop->fsync) continue; lower_file = unionfs_lower_file_idx(file, bindex); lower_dentry = unionfs_lower_dentry_idx(dentry, bindex); mutex_lock(&lower_inode->i_mutex); err = lower_inode->i_fop->fsync(lower_file, lower_dentry, datasync); if (!err && bindex == bstart) fsstack_copy_attr_times(inode, lower_inode); mutex_unlock(&lower_inode->i_mutex); if (err) goto out; } out: if (!err) unionfs_check_file(file); unionfs_unlock_dentry(dentry); unionfs_unlock_parent(dentry, parent); unionfs_read_unlock(dentry->d_sb); return err; }
/* * put all references held by upper struct file and free lower file pointer * array */ static void cleanup_file(struct file *file) { int bindex, bstart, bend; struct file **lower_files; struct file *lower_file; struct super_block *sb = file->f_path.dentry->d_sb; lower_files = UNIONFS_F(file)->lower_files; bstart = fbstart(file); bend = fbend(file); for (bindex = bstart; bindex <= bend; bindex++) { int i; /* holds (possibly) updated branch index */ int old_bid; lower_file = unionfs_lower_file_idx(file, bindex); if (!lower_file) continue; /* * Find new index of matching branch with an open * file, since branches could have been added or * deleted causing the one with open files to shift. */ old_bid = UNIONFS_F(file)->saved_branch_ids[bindex]; i = branch_id_to_idx(sb, old_bid); if (unlikely(i < 0)) { printk(KERN_ERR "unionfs: no superblock for " "file %p\n", file); continue; } /* decrement count of open files */ branchput(sb, i); /* * fput will perform an mntput for us on the correct branch. * Although we're using the file's old branch configuration, * bindex, which is the old index, correctly points to the * right branch in the file's branch list. In other words, * we're going to mntput the correct branch even if branches * have been added/removed. */ fput(lower_file); UNIONFS_F(file)->lower_files[bindex] = NULL; UNIONFS_F(file)->saved_branch_ids[bindex] = -1; } UNIONFS_F(file)->lower_files = NULL; kfree(lower_files); kfree(UNIONFS_F(file)->saved_branch_ids); /* set to NULL because caller needs to know if to kfree on error */ UNIONFS_F(file)->saved_branch_ids = NULL; }
int unionfs_flush(struct file *file, fl_owner_t id) { int err = 0; struct file *lower_file = NULL; struct dentry *dentry = file->f_path.dentry; struct dentry *parent; int bindex, bstart, bend; unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT); parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT); unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD); err = unionfs_file_revalidate(file, parent, UNIONFS_F(file)->wrote_to_file); if (unlikely(err)) goto out; unionfs_check_file(file); bstart = fbstart(file); bend = fbend(file); for (bindex = bstart; bindex <= bend; bindex++) { lower_file = unionfs_lower_file_idx(file, bindex); if (lower_file && lower_file->f_op && lower_file->f_op->flush) { err = lower_file->f_op->flush(lower_file, id); if (err) goto out; } } out: if (!err) unionfs_check_file(file); unionfs_unlock_dentry(dentry); unionfs_unlock_parent(dentry, parent); unionfs_read_unlock(dentry->d_sb); return err; }
static int unionfs_readdir(struct file *file, void *dirent, filldir_t filldir) { int err = 0; struct file *lower_file = NULL; struct dentry *dentry = file->f_path.dentry; struct dentry *parent; struct inode *inode = NULL; struct unionfs_getdents_callback buf; struct unionfs_dir_state *uds; int bend; loff_t offset; unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT); parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT); unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD); err = unionfs_file_revalidate(file, parent, false); if (unlikely(err)) goto out; inode = dentry->d_inode; uds = UNIONFS_F(file)->rdstate; if (!uds) { if (file->f_pos == DIREOF) { goto out; } else if (file->f_pos > 0) { uds = find_rdstate(inode, file->f_pos); if (unlikely(!uds)) { err = -ESTALE; goto out; } UNIONFS_F(file)->rdstate = uds; } else { init_rdstate(file); uds = UNIONFS_F(file)->rdstate; } } bend = fbend(file); while (uds->bindex <= bend) { lower_file = unionfs_lower_file_idx(file, uds->bindex); if (!lower_file) { uds->bindex++; uds->dirpos = 0; continue; } /* prepare callback buffer */ buf.filldir_called = 0; buf.filldir_error = 0; buf.entries_written = 0; buf.dirent = dirent; buf.filldir = filldir; buf.rdstate = uds; buf.sb = inode->i_sb; /* Read starting from where we last left off. */ offset = vfs_llseek(lower_file, uds->dirpos, SEEK_SET); if (offset < 0) { err = offset; goto out; } err = vfs_readdir(lower_file, unionfs_filldir, &buf); /* Save the position for when we continue. */ offset = vfs_llseek(lower_file, 0, SEEK_CUR); if (offset < 0) { err = offset; goto out; } uds->dirpos = offset; /* Copy the atime. */ fsstack_copy_attr_atime(inode, lower_file->f_path.dentry->d_inode); if (err < 0) goto out; if (buf.filldir_error) break; if (!buf.entries_written) { uds->bindex++; uds->dirpos = 0; } } if (!buf.filldir_error && uds->bindex >= bend) { /* Save the number of hash entries for next time. */ UNIONFS_I(inode)->hashsize = uds->hashentries; free_rdstate(uds); UNIONFS_F(file)->rdstate = NULL; file->f_pos = DIREOF; } else { file->f_pos = rdstate2offset(uds); } out: if (!err) unionfs_check_file(file); unionfs_unlock_dentry(dentry); unionfs_unlock_parent(dentry, parent); unionfs_read_unlock(dentry->d_sb); return err; }
void __unionfs_check_file(const struct file *file, const char *fname, const char *fxn, int line) { int bindex; int dstart, dend, fstart, fend; struct dentry *dentry; struct file *lower_file; struct inode *inode; struct super_block *sb; int printed_caller = 0; BUG_ON(!file); dentry = file->f_path.dentry; sb = dentry->d_sb; dstart = dbstart(dentry); dend = dbend(dentry); BUG_ON(dstart > dend); fstart = fbstart(file); fend = fbend(file); BUG_ON(fstart > fend); if (unlikely((fstart == -1 && fend != -1) || (fstart != -1 && fend == -1))) { PRINT_CALLER(fname, fxn, line); pr_debug(" CF0: file/dentry=%p:%p fstart/end=%d:%d\n", file, dentry, fstart, fend); } if (unlikely(fstart != dstart)) { PRINT_CALLER(fname, fxn, line); pr_debug(" CF1: file/dentry=%p:%p fstart=%d dstart=%d\n", file, dentry, fstart, dstart); } if (unlikely(fend != dend)) { PRINT_CALLER(fname, fxn, line); pr_debug(" CF2: file/dentry=%p:%p fend=%d dend=%d\n", file, dentry, fend, dend); } inode = dentry->d_inode; if (!S_ISDIR(inode->i_mode)) { if (unlikely(fend != fstart)) { PRINT_CALLER(fname, fxn, line); pr_debug(" CF3: file/inode=%p:%p fstart=%d fend=%d\n", file, inode, fstart, fend); } if (unlikely(dend != dstart)) { PRINT_CALLER(fname, fxn, line); pr_debug(" CF4: file/dentry=%p:%p dstart=%d dend=%d\n", file, dentry, dstart, dend); } } /* * check for NULL dentries inside the start/end range, or * non-NULL dentries outside the start/end range. */ for (bindex = sbstart(sb); bindex < sbmax(sb); bindex++) { lower_file = unionfs_lower_file_idx(file, bindex); if (lower_file) { if (unlikely(bindex < fstart || bindex > fend)) { PRINT_CALLER(fname, fxn, line); pr_debug(" CF5: file/lower=%p:%p bindex=%d " "fstart/end=%d:%d\n", file, lower_file, bindex, fstart, fend); } } else { /* lower_file == NULL */ if (bindex >= fstart && bindex <= fend) { /* * directories can have NULL lower inodes in * b/t start/end, but NOT if at the * start/end range. */ if (unlikely(!(S_ISDIR(inode->i_mode) && bindex > fstart && bindex < fend))) { PRINT_CALLER(fname, fxn, line); pr_debug(" CF6: file/lower=%p:%p " "bindex=%d fstart/end=%d:%d\n", file, lower_file, bindex, fstart, fend); } } } } __unionfs_check_dentry(dentry, fname, fxn, line); }
/* * release all lower object references & free the file info structure * * No need to grab sb info's rwsem. */ int unionfs_file_release(struct inode *inode, struct file *file) { struct file *lower_file = NULL; struct unionfs_file_info *fileinfo; struct unionfs_inode_info *inodeinfo; struct super_block *sb = inode->i_sb; struct dentry *dentry = file->f_path.dentry; struct dentry *parent; int bindex, bstart, bend; int fgen, err = 0; /* * Since mm/memory.c:might_fault() (under PROVE_LOCKING) was * modified in 2.6.29-rc1 to call might_lock_read on mmap_sem, this * has been causing false positives in file system stacking layers. * In particular, our ->mmap is called after sys_mmap2 already holds * mmap_sem, then we lock our own mutexes; but earlier, it's * possible for lockdep to have locked our mutexes first, and then * we call a lower ->readdir which could call might_fault. The * different ordering of the locks is what lockdep complains about * -- unnecessarily. Therefore, we have no choice but to tell * lockdep to temporarily turn off lockdep here. Note: the comments * inside might_sleep also suggest that it would have been * nicer to only annotate paths that needs that might_lock_read. */ lockdep_off(); unionfs_read_lock(sb, UNIONFS_SMUTEX_PARENT); parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT); unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD); /* * We try to revalidate, but the VFS ignores return return values * from file->release, so we must always try to succeed here, * including to do the kfree and dput below. So if revalidation * failed, all we can do is print some message and keep going. */ err = unionfs_file_revalidate(file, parent, UNIONFS_F(file)->wrote_to_file); if (!err) unionfs_check_file(file); fileinfo = UNIONFS_F(file); BUG_ON(file->f_path.dentry->d_inode != inode); inodeinfo = UNIONFS_I(inode); /* fput all the lower files */ fgen = atomic_read(&fileinfo->generation); bstart = fbstart(file); bend = fbend(file); for (bindex = bstart; bindex <= bend; bindex++) { lower_file = unionfs_lower_file_idx(file, bindex); if (lower_file) { unionfs_set_lower_file_idx(file, bindex, NULL); fput(lower_file); branchput(sb, bindex); } /* if there are no more refs to the dentry, dput it */ if (d_deleted(dentry)) { dput(unionfs_lower_dentry_idx(dentry, bindex)); unionfs_set_lower_dentry_idx(dentry, bindex, NULL); } } kfree(fileinfo->lower_files); kfree(fileinfo->saved_branch_ids); if (fileinfo->rdstate) { fileinfo->rdstate->access = jiffies; spin_lock(&inodeinfo->rdlock); inodeinfo->rdcount++; list_add_tail(&fileinfo->rdstate->cache, &inodeinfo->readdircache); mark_inode_dirty(inode); spin_unlock(&inodeinfo->rdlock); fileinfo->rdstate = NULL; } kfree(fileinfo); unionfs_unlock_dentry(dentry); unionfs_unlock_parent(dentry, parent); unionfs_read_unlock(sb); lockdep_on(); return err; }
int unionfs_open(struct inode *inode, struct file *file) { int err = 0; struct file *lower_file = NULL; struct dentry *dentry = file->f_path.dentry; struct dentry *parent; int bindex = 0, bstart = 0, bend = 0; int size; int valid = 0; unionfs_read_lock(inode->i_sb, UNIONFS_SMUTEX_PARENT); parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT); unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD); /* don't open unhashed/deleted files */ if (d_deleted(dentry)) { err = -ENOENT; goto out_nofree; } /* XXX: should I change 'false' below to the 'willwrite' flag? */ valid = __unionfs_d_revalidate(dentry, parent, false); if (unlikely(!valid)) { err = -ESTALE; goto out_nofree; } file->private_data = kzalloc(sizeof(struct unionfs_file_info), GFP_KERNEL); if (unlikely(!UNIONFS_F(file))) { err = -ENOMEM; goto out_nofree; } fbstart(file) = -1; fbend(file) = -1; atomic_set(&UNIONFS_F(file)->generation, atomic_read(&UNIONFS_I(inode)->generation)); size = sizeof(struct file *) * sbmax(inode->i_sb); UNIONFS_F(file)->lower_files = kzalloc(size, GFP_KERNEL); if (unlikely(!UNIONFS_F(file)->lower_files)) { err = -ENOMEM; goto out; } size = sizeof(int) * sbmax(inode->i_sb); UNIONFS_F(file)->saved_branch_ids = kzalloc(size, GFP_KERNEL); if (unlikely(!UNIONFS_F(file)->saved_branch_ids)) { err = -ENOMEM; goto out; } bstart = fbstart(file) = dbstart(dentry); bend = fbend(file) = dbend(dentry); /* * open all directories and make the unionfs file struct point to * these lower file structs */ if (S_ISDIR(inode->i_mode)) err = __open_dir(inode, file); /* open a dir */ else err = __open_file(inode, file, parent); /* open a file */ /* freeing the allocated resources, and fput the opened files */ if (err) { for (bindex = bstart; bindex <= bend; bindex++) { lower_file = unionfs_lower_file_idx(file, bindex); if (!lower_file) continue; branchput(dentry->d_sb, bindex); /* fput calls dput for lower_dentry */ fput(lower_file); } } out: if (err) { kfree(UNIONFS_F(file)->lower_files); kfree(UNIONFS_F(file)->saved_branch_ids); kfree(UNIONFS_F(file)); } out_nofree: if (!err) { unionfs_postcopyup_setmnt(dentry); unionfs_copy_attr_times(inode); unionfs_check_file(file); unionfs_check_inode(inode); } unionfs_unlock_dentry(dentry); unionfs_unlock_parent(dentry, parent); unionfs_read_unlock(inode->i_sb); return err; }