ANDROID: sdcardfs: Add sdcardfs filesystem

Bug: 11118565
Bug: 27915347
Bug: 27992761
Bug: 28024488
Bug: 30013843
Bug: 30954918
Bug: 34133558
Bug: 34262585
Bug: 34542611
Bug: 34691169
Bug: 34723223
Bug: 35307857
Bug: 35331000
Bug: 35633782
Bug: 35643557
Bug: 35666680
bug: 35766959
Bug: 35766959
Bug: 35848445
Bug: 36004503
Bug: 36007653
Bug: 36138424
Bug: 36160015
Bug: 37193650
Bug: 37231161
Bug: 37488099
Bug: 37516160
Bug: 38045152
Bug: 38117720
Bug: 38502532
Bug: 62390017
Bug: 63245673
Bug: 63260873
Bug: 63785372
Bug: 64672411
Bug: 70278506
Bug: 72007585
Bug: 73055997
Bug: 73287721
Bug: 75987238
Bug: 77923821
Bug: 78262592
Bug: 111641492
Bug: 111642636
Bug: 111860541
Bug: 120446149
Change-Id: Ic1e01e602ce335d97342be54f3da0c5c65c087cc
Signed-off-by: Daniel Rosenberg <drosen@google.com>
[astrachan: Folded the following changes into this patch:
            903cea7ab0b2 ("ANDROID: Included sdcardfs source code for kernel 3.0")
            612a725e3d97 ("ANDROID: Port of sdcardfs to 4.4")
            e4187c55208b ("ANDROID: Changed type-casting in packagelist management")
            cf76072a5cd8 ("ANDROID: sdcardfs: Bring up to date with Android M permissions:")
            a43aa502c608 ("ANDROID: sdcardfs: Add support for d_canonical_path")
            d8fefbf85af2 ("ANDROID: sdcardfs: remove effectless config option")
            416677409336 ("ANDROID: sdcardfs: Remove unused code")
            8e49a570d351 ("ANDROID: sdcardfs: remove unneeded __init and __exit")
            40ee0e93f1d7 ("ANDROID: sdcardfs: Truncate packages_gid.list on overflow")
            b1d9602aa3fe ("ANDROID: sdcardfs: fix itnull.cocci warnings")
            60a177f5a167 ("ANDROID: sdcardfs: override umask on mkdir and create")
            efb3d2695203 ("ANDROID: sdcardfs: Check for other cases on path lookup")
            0da87f63666f ("ANDROID: sdcardfs: Fix locking for permission fix up")
            75b93060655e ("ANDROID: sdcardfs: Switch package list to RCU")
            657b0a00f497 ("ANDROID: sdcardfs: Added top to sdcardfs_inode_info")
            5008d91cba25 ("ANDROID: sdcardfs: fix external storage exporting incorrect uid")
            e06c452d0d07 ("ANDROID: sdcardfs: Move directory unlock before touch")
            72e5443a2816 ("ANDROID: sdcardfs: User new permission2 functions")
            ae8be7da556d ("ANDROID: sdcardfs: Add gid and mask to private mount data")
            151a3efe57a6 ("ANDROID: sdcardfs: Use per mount permissions")
            cff865a370f3 ("ANDROID: sdcardfs: Switch ->d_inode to d_inode()")
            065ac66804bf ("ANDROID: sdcardfs: Fix locking issue with permision fix up")
            31ea603eb3c4 ("ANDROID: sdcardfs: use wrappers to access i_mutex")
            c25c2f5018a2 ("ANDROID: sdcardfs: add parent pointer into dentry name hash")
            58616bb4ec68 ("ANDROID: sdcardfs: get rid of 'parent' argument of ->d_compare()")
            1654d7ffdd20 ("ANDROID: sdcardfs: Propagate dentry down to inode_change_ok()")
            39335cac1d2f ("ANDROID: sdcardfs: make it use new .rename i_op")
            7622bb3fcc79 ("ANDROID: sdcardfs: eliminate the offset argument to ->direct_IO")
            843bd7295ee0 ("ANDROID: sdcardfs: Allow non-owners to touch")
            e3d74804d174 ("ANDROID: sdcardfs: Refactor configfs interface")
            5833eda87a72 ("ANDROID: sdcardfs: add support for user permission isolation")
            d83fb1f41dd4 ("ANDROID: sdcardfs: Remove redundant operation")
            8767af17c0e5 ("ANDROID: sdcardfs: Add GID Derivation to sdcardfs")
            7119d96ad3ee ("ANDROID: sdcardfs: switch to full_name_hash and qstr")
            778e02a54859 ("ANDROID: sdcardfs: Switch strcasecmp for internal call")
            cd4965d04404 ("ANDROID: sdcardfs: Fix incorrect hash")
            40a2ee053505 ("ANDROID: sdcardfs: Add missing path_put")
            da5342bac57a ("ANDROID: sdcardfs: Don't bother deleting freelist")
            c91857b01e05 ("ANDROID: sdcardfs: implement vm_ops->page_mkwrite")
            f62b3906044b ("ANDROID: sdcardfs: support direct-IO (DIO) operations")
            c2e216d36d63 ("ANDROID: sdcardfs: Fix case insensitive lookup")
            57b92ab6f774 ("ANDROID: sdcardfs: rate limit warning print")
            8534cee39a81 ("ANDROID: sdcardfs: Replace get/put with d_lock")
            156085b2fccf ("ANDROID: sdcardfs: Use spin_lock_nested")
            8a260cabac4e ("ANDROID: sdcardfs: Switch to internal case insensitive compare")
            a8d51569573c ("ANDROID: sdcardfs: Use d_invalidate instead of drop_recurisve")
            932a6071de63 ("ANDROID: sdcardfs: Get the blocksize from the lower fs")
            0ad4c0f87527 ("ANDROID: sdcardfs: declare MODULE_ALIAS_FS")
            b97c83b5b683 ("ANDROID: sdcardfs: Use case insensitive hash function")
            9920dfb08265 ("ANDROID: sdcardfs: move path_put outside of spinlock")
            f9a25348b233 ("ANDROID: sdcardfs: Remove uninformative prints")
            720d9030bea1 ("ANDROID: sdcardfs: Fix gid issue")
            4cbb7fa6e66c ("ANDROID: sdcardfs: correct order of descriptors")
            6cff6cc301ed ("ANDROID: sdcardfs: Fix formatting")
            ac2a40412e26 ("ANDROID: sdcardfs: Fix style issues with comments")
            2212bb8ec064 ("ANDROID: sdcardfs: remove unneeded null check")
            4c1a0add8d21 ("ANDROID: sdcardfs: Use pr_[...] instead of printk")
            74535fe211ac ("ANDROID: sdcardfs: Use to kstrout")
            e6cf8dffd014 ("ANDROID: sdcardfs: Use seq_puts over seq_printf")
            2b1ac93a90b6 ("ANDROID: sdcardfs: Fix style issues in macros")
            bab6d117426f ("ANDROID: sdcardfs: remove unnecessary call to do_munmap")
            1c0bf09f19b6 ("ANDROID: sdcardfs: copy lower inode attributes in ->ioctl")
            42f3db55942b ("ANDROID: sdcardfs: fix ->llseek to update upper and lower offset")
            97ad6205055e ("ANDROID: sdcardfs: add read_iter/write_iter opeations")
            be9abc81332b ("ANDROID: sdcardfs: use d_splice_alias")
            4e90114cb1b4 ("ANDROID: sdcardfs: update module info")
            0e1f7ab14924 ("ANDROID: sdcardfs: Directly pass lower file for mmap")
            28be4beb43f9 ("ANDROID: sdcardfs: Change cache GID value")
            9fc2c452aefe ("ANDROID: sdcardfs: ->iget fixes")
            9bb72cf15cbc ("ANDROID: sdcardfs: Don't do d_add for lower fs")
            1bc21a04c11b ("ANDROID: sdcardfs: Don't complain in fixup_lower_ownership")
            0fb5b10b28a9 ("ANDROID: sdcardfs: Use filesystem specific hash")
            30e2f0aadce2 ("ANDROID: sdcardfs: Copy meta-data from lower inode")
            f748c7053194 ("ANDROID: sdcardfs: Avoid setting GIDs outside of valid ranges")
            3d38f08bacdb ("ANDROID: sdcardfs: Call lower fs's revalidate")
            2d1f1c203978 ("ANDROID: sdcardfs: Don't iput if we didn't igrab")
            857fc5e717fc ("ANDROID: sdcardfs: fix sdcardfs_destroy_inode for the inode RCU approach")
            4fceeccf1d23 ("ANDROID: sdcardfs: Move top to its own struct")
            f51470044a15 ("ANDROID: sdcardfs: Check for NULL in revalidate")
            8c7f6c97ac81 ("ANDROID: sdcardfs: d_splice_alias can return error values")
            17da01b37d61 ("ANDROID: sdcardfs: remove dead function open_flags_to_access_mode()")
            16662dd604be ("ANDROID: sdcardfs: use mount_nodev and fix a issue in sdcardfs_kill_sb")
            43c0dca6039a ("ANDROID: sdcardfs: Remove unnecessary lock")
            48960c25cdc1 ("ANDROID: sdcardfs: override credential for ioctl to lower fs")
            5d6410b9a88d ("ANDROID: Sdcardfs: Move gid derivation under flag")
            c7dd98431f83 ("ANDROID: sdcardfs: Add default_normal option")
            db9bf31a5d86 ("ANDROID: sdcardfs: port to 4.14")
            c70c9d1e82d2 ("ANDROID: sdcardfs: Use lower getattr times/size")
            04e961477d62 ("ANDROID: sdcardfs: Protect set_top")
            1ed04b79d281 ("ANDROID: sdcardfs: Hold i_mutex for i_size_write")
            77f52fc10982 ("ANDROID: sdcardfs: Set num in extension_details during make_item")
            d71596efa247 ("ANDROID: sdcardfs: fix lock issue on 32 bit/SMP architectures")
            ee6b07fced4a ("ANDROID: sdcardfs: Fix sdcardfs to stop creating cases-sensitive duplicate entries.")
            ce12807d5b75 ("ANDROID: sdcardfs: Check for private data earlier")
            c080450304cd ("ANDROID: sdcardfs: d_make_root calls iput")
            900e77796781 ("ANDROID: sdcardfs: Set s_root to NULL after putting")
            49092e89ffa4 ("ANDROID: sdcardfs: Don't d_drop in d_revalidate")
            e1f978bc9b9c ("ANDROID: sdcardfs: fix potential crash when reserved_mb is not zero")
            faa148eaf8ed ("ANDROID: sdcardfs: Check stacked filesystem depth")
            6edd721e972c ("ANDROID: sdcardfs: Don't use OVERRIDE_CRED macro")
            11ca578b4336 ("ANDROID: sdcardfs: Change current->fs under lock")
            83dea6ba6ea7 ("ANDROID: sdcardfs: Use inode iversion helpers")
            12064f3a794e ("ANDROID: sdcardfs: Add option to drop unused dentries")
            d9fe221bbf84 ("ANDROID: sdcardfs: Add sandbox")
            f544ad0b1547 ("ANDROID: sdcardfs: Add option to not link obb")]
Signed-off-by: Alistair Strachan <astrachan@google.com>
diff --git a/fs/sdcardfs/dentry.c b/fs/sdcardfs/dentry.c
new file mode 100644
index 0000000..cb573f1
--- /dev/null
+++ b/fs/sdcardfs/dentry.c
@@ -0,0 +1,196 @@
+/*
+ * fs/sdcardfs/dentry.c
+ *
+ * Copyright (c) 2013 Samsung Electronics Co. Ltd
+ *   Authors: Daeho Jeong, Woojoong Lee, Seunghwan Hyun,
+ *               Sunghwan Yun, Sungjong Seo
+ *
+ * This program has been developed as a stackable file system based on
+ * the WrapFS which written by
+ *
+ * Copyright (c) 1998-2011 Erez Zadok
+ * Copyright (c) 2009     Shrikar Archak
+ * Copyright (c) 2003-2011 Stony Brook University
+ * Copyright (c) 2003-2011 The Research Foundation of SUNY
+ *
+ * This file is dual licensed.  It may be redistributed and/or modified
+ * under the terms of the Apache 2.0 License OR version 2 of the GNU
+ * General Public License.
+ */
+
+#include "sdcardfs.h"
+#include "linux/ctype.h"
+
+/*
+ * returns: -ERRNO if error (returned to user)
+ *          0: tell VFS to invalidate dentry
+ *          1: dentry is valid
+ */
+static int sdcardfs_d_revalidate(struct dentry *dentry, unsigned int flags)
+{
+	int err = 1;
+	struct path parent_lower_path, lower_path;
+	struct dentry *parent_dentry = NULL;
+	struct dentry *parent_lower_dentry = NULL;
+	struct dentry *lower_cur_parent_dentry = NULL;
+	struct dentry *lower_dentry = NULL;
+	struct inode *inode;
+	struct sdcardfs_inode_data *data;
+
+	if (flags & LOOKUP_RCU)
+		return -ECHILD;
+
+	spin_lock(&dentry->d_lock);
+	if (IS_ROOT(dentry)) {
+		spin_unlock(&dentry->d_lock);
+		return 1;
+	}
+	spin_unlock(&dentry->d_lock);
+
+	/* check uninitialized obb_dentry and
+	 * whether the base obbpath has been changed or not
+	 */
+	if (is_obbpath_invalid(dentry)) {
+		return 0;
+	}
+
+	parent_dentry = dget_parent(dentry);
+	sdcardfs_get_lower_path(parent_dentry, &parent_lower_path);
+	sdcardfs_get_real_lower(dentry, &lower_path);
+	parent_lower_dentry = parent_lower_path.dentry;
+	lower_dentry = lower_path.dentry;
+	lower_cur_parent_dentry = dget_parent(lower_dentry);
+
+	if ((lower_dentry->d_flags & DCACHE_OP_REVALIDATE)) {
+		err = lower_dentry->d_op->d_revalidate(lower_dentry, flags);
+		if (err == 0) {
+			goto out;
+		}
+	}
+
+	spin_lock(&lower_dentry->d_lock);
+	if (d_unhashed(lower_dentry)) {
+		spin_unlock(&lower_dentry->d_lock);
+		err = 0;
+		goto out;
+	}
+	spin_unlock(&lower_dentry->d_lock);
+
+	if (parent_lower_dentry != lower_cur_parent_dentry) {
+		err = 0;
+		goto out;
+	}
+
+	if (dentry < lower_dentry) {
+		spin_lock(&dentry->d_lock);
+		spin_lock_nested(&lower_dentry->d_lock, DENTRY_D_LOCK_NESTED);
+	} else {
+		spin_lock(&lower_dentry->d_lock);
+		spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
+	}
+
+	if (!qstr_case_eq(&dentry->d_name, &lower_dentry->d_name)) {
+		err = 0;
+	}
+
+	if (dentry < lower_dentry) {
+		spin_unlock(&lower_dentry->d_lock);
+		spin_unlock(&dentry->d_lock);
+	} else {
+		spin_unlock(&dentry->d_lock);
+		spin_unlock(&lower_dentry->d_lock);
+	}
+	if (!err)
+		goto out;
+
+	/* If our top's inode is gone, we may be out of date */
+	inode = igrab(d_inode(dentry));
+	if (inode) {
+		data = top_data_get(SDCARDFS_I(inode));
+		if (!data || data->abandoned) {
+			err = 0;
+		}
+		if (data)
+			data_put(data);
+		iput(inode);
+	}
+
+out:
+	dput(parent_dentry);
+	dput(lower_cur_parent_dentry);
+	sdcardfs_put_lower_path(parent_dentry, &parent_lower_path);
+	sdcardfs_put_real_lower(dentry, &lower_path);
+	return err;
+}
+
+/* 1 = delete, 0 = cache */
+static int sdcardfs_d_delete(const struct dentry *d)
+{
+	return SDCARDFS_SB(d->d_sb)->options.nocache ? 1 : 0;
+}
+
+static void sdcardfs_d_release(struct dentry *dentry)
+{
+	if (!dentry || !dentry->d_fsdata)
+		return;
+	/* release and reset the lower paths */
+	if (has_graft_path(dentry))
+		sdcardfs_put_reset_orig_path(dentry);
+	sdcardfs_put_reset_lower_path(dentry);
+	free_dentry_private_data(dentry);
+}
+
+static int sdcardfs_hash_ci(const struct dentry *dentry,
+				struct qstr *qstr)
+{
+	/*
+	 * This function is copy of vfat_hashi.
+	 * FIXME Should we support national language?
+	 *       Refer to vfat_hashi()
+	 * struct nls_table *t = MSDOS_SB(dentry->d_sb)->nls_io;
+	 */
+	const unsigned char *name;
+	unsigned int len;
+	unsigned long hash;
+
+	name = qstr->name;
+	len = qstr->len;
+
+	hash = init_name_hash(dentry);
+	while (len--)
+		hash = partial_name_hash(tolower(*name++), hash);
+	qstr->hash = end_name_hash(hash);
+
+	return 0;
+}
+
+/*
+ * Case insensitive compare of two vfat names.
+ */
+static int sdcardfs_cmp_ci(const struct dentry *dentry,
+		unsigned int len, const char *str, const struct qstr *name)
+{
+	/* FIXME Should we support national language? */
+
+	if (name->len == len) {
+		if (str_n_case_eq(name->name, str, len))
+			return 0;
+	}
+	return 1;
+}
+
+static void sdcardfs_canonical_path(const struct path *path,
+				struct path *actual_path)
+{
+	sdcardfs_get_real_lower(path->dentry, actual_path);
+}
+
+const struct dentry_operations sdcardfs_ci_dops = {
+	.d_revalidate	= sdcardfs_d_revalidate,
+	.d_delete	= sdcardfs_d_delete,
+	.d_release	= sdcardfs_d_release,
+	.d_hash	= sdcardfs_hash_ci,
+	.d_compare	= sdcardfs_cmp_ci,
+	.d_canonical_path = sdcardfs_canonical_path,
+};
+