--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2018-2024 Oracle. All Rights Reserved.
+ * Author: Darrick J. Wong <djwong@kernel.org>
+ */
+#include "libxfs_priv.h"
+#include "xfs_fs.h"
+#include "xfs_shared.h"
+#include "xfs_format.h"
+#include "xfs_log_format.h"
+#include "xfs_trans_resv.h"
+#include "xfs_bit.h"
+#include "xfs_sb.h"
+#include "xfs_mount.h"
+#include "xfs_defer.h"
+#include "xfs_trans.h"
+#include "xfs_metafile.h"
+#include "xfs_metadir.h"
+#include "xfs_trace.h"
+#include "xfs_inode.h"
+#include "xfs_ialloc.h"
+#include "xfs_bmap_btree.h"
+#include "xfs_da_format.h"
+#include "xfs_da_btree.h"
+#include "xfs_trans_space.h"
+#include "xfs_ag.h"
+#include "xfs_dir2.h"
+#include "xfs_dir2_priv.h"
+#include "xfs_parent.h"
+
+/*
+ * Metadata Directory Tree
+ * =======================
+ *
+ * These functions provide an abstraction layer for looking up, creating, and
+ * deleting metadata inodes that live within a special metadata directory tree.
+ *
+ * This code does not manage the five existing metadata inodes: real time
+ * bitmap & summary; and the user, group, and quotas. All other metadata
+ * inodes must use only the xfs_meta{dir,file}_* functions.
+ *
+ * Callers wishing to create or hardlink a metadata inode must create an
+ * xfs_metadir_update structure, call the appropriate xfs_metadir* function,
+ * and then call xfs_metadir_commit or xfs_metadir_cancel to commit or cancel
+ * the update. Files in the metadata directory tree currently cannot be
+ * unlinked.
+ *
+ * When the metadir feature is enabled, all metadata inodes must have the
+ * "metadata" inode flag set to prevent them from being exposed to the outside
+ * world.
+ *
+ * Callers must take the ILOCK of any inode in the metadata directory tree to
+ * synchronize access to that inode. It is never necessary to take the IOLOCK
+ * or the MMAPLOCK since metadata inodes must not be exposed to user space.
+ */
+
+static inline void
+xfs_metadir_set_xname(
+ struct xfs_name *xname,
+ const char *path,
+ unsigned char ftype)
+{
+ xname->name = (const unsigned char *)path;
+ xname->len = strlen(path);
+ xname->type = ftype;
+}
+
+/*
+ * Given a parent directory @dp and a metadata inode path component @xname,
+ * Look up the inode number in the directory, returning it in @ino.
+ * @xname.type must match the directory entry's ftype.
+ *
+ * Caller must hold ILOCK_EXCL.
+ */
+static inline int
+xfs_metadir_lookup(
+ struct xfs_trans *tp,
+ struct xfs_inode *dp,
+ struct xfs_name *xname,
+ xfs_ino_t *ino)
+{
+ struct xfs_mount *mp = dp->i_mount;
+ struct xfs_da_args args = {
+ .trans = tp,
+ .dp = dp,
+ .geo = mp->m_dir_geo,
+ .name = xname->name,
+ .namelen = xname->len,
+ .hashval = xfs_dir2_hashname(mp, xname),
+ .whichfork = XFS_DATA_FORK,
+ .op_flags = XFS_DA_OP_OKNOENT,
+ .owner = dp->i_ino,
+ };
+ int error;
+
+ if (!S_ISDIR(VFS_I(dp)->i_mode))
+ return -EFSCORRUPTED;
+ if (xfs_is_shutdown(mp))
+ return -EIO;
+
+ error = xfs_dir_lookup_args(&args);
+ if (error)
+ return error;
+
+ if (!xfs_verify_ino(mp, args.inumber))
+ return -EFSCORRUPTED;
+ if (xname->type != XFS_DIR3_FT_UNKNOWN && xname->type != args.filetype)
+ return -EFSCORRUPTED;
+
+ trace_xfs_metadir_lookup(dp, xname, args.inumber);
+ *ino = args.inumber;
+ return 0;
+}
+
+/*
+ * Look up and read a metadata inode from the metadata directory. If the path
+ * component doesn't exist, return -ENOENT.
+ */
+int
+xfs_metadir_load(
+ struct xfs_trans *tp,
+ struct xfs_inode *dp,
+ const char *path,
+ enum xfs_metafile_type metafile_type,
+ struct xfs_inode **ipp)
+{
+ struct xfs_name xname;
+ xfs_ino_t ino;
+ int error;
+
+ xfs_metadir_set_xname(&xname, path, XFS_DIR3_FT_UNKNOWN);
+
+ xfs_ilock(dp, XFS_ILOCK_EXCL);
+ error = xfs_metadir_lookup(tp, dp, &xname, &ino);
+ xfs_iunlock(dp, XFS_ILOCK_EXCL);
+ if (error)
+ return error;
+ return xfs_trans_metafile_iget(tp, ino, metafile_type, ipp);
+}
+
+/*
+ * Unlock and release resources after committing (or cancelling) a metadata
+ * directory tree operation. The caller retains its reference to @upd->ip
+ * and must release it explicitly.
+ */
+static inline void
+xfs_metadir_teardown(
+ struct xfs_metadir_update *upd,
+ int error)
+{
+ trace_xfs_metadir_teardown(upd, error);
+
+ if (upd->ppargs) {
+ xfs_parent_finish(upd->dp->i_mount, upd->ppargs);
+ upd->ppargs = NULL;
+ }
+
+ if (upd->ip) {
+ if (upd->ip_locked)
+ xfs_iunlock(upd->ip, XFS_ILOCK_EXCL);
+ upd->ip_locked = false;
+ }
+
+ if (upd->dp_locked)
+ xfs_iunlock(upd->dp, XFS_ILOCK_EXCL);
+ upd->dp_locked = false;
+}
+
+/*
+ * Begin the process of creating a metadata file by allocating transactions
+ * and taking whatever resources we're going to need.
+ */
+int
+xfs_metadir_start_create(
+ struct xfs_metadir_update *upd)
+{
+ struct xfs_mount *mp = upd->dp->i_mount;
+ int error;
+
+ ASSERT(upd->dp != NULL);
+ ASSERT(upd->ip == NULL);
+ ASSERT(xfs_has_metadir(mp));
+ ASSERT(upd->metafile_type != XFS_METAFILE_UNKNOWN);
+
+ error = xfs_parent_start(mp, &upd->ppargs);
+ if (error)
+ return error;
+
+ /*
+ * If we ever need the ability to create rt metadata files on a
+ * pre-metadir filesystem, we'll need to dqattach the parent here.
+ * Currently we assume that mkfs will create the files and quotacheck
+ * will account for them.
+ */
+
+ error = xfs_trans_alloc(mp, &M_RES(mp)->tr_create,
+ xfs_create_space_res(mp, MAXNAMELEN), 0, 0, &upd->tp);
+ if (error)
+ goto out_teardown;
+
+ /*
+ * Lock the parent directory if there is one. We can't ijoin it to
+ * the transaction until after the child file has been created.
+ */
+ xfs_ilock(upd->dp, XFS_ILOCK_EXCL | XFS_ILOCK_PARENT);
+ upd->dp_locked = true;
+
+ trace_xfs_metadir_start_create(upd);
+ return 0;
+out_teardown:
+ xfs_metadir_teardown(upd, error);
+ return error;
+}
+
+/*
+ * Create a metadata inode with the given @mode, and insert it into the
+ * metadata directory tree at the given @upd->path. The path up to the final
+ * component must already exist. The final path component must not exist.
+ *
+ * The new metadata inode will be attached to the update structure @upd->ip,
+ * with the ILOCK held until the caller releases it.
+ *
+ * NOTE: This function may return a new inode to the caller even if it returns
+ * a negative error code. If an inode is passed back, the caller must finish
+ * setting up the inode before releasing it.
+ */
+int
+xfs_metadir_create(
+ struct xfs_metadir_update *upd,
+ umode_t mode)
+{
+ struct xfs_icreate_args args = {
+ .pip = upd->dp,
+ .mode = mode,
+ };
+ struct xfs_name xname;
+ struct xfs_dir_update du = {
+ .dp = upd->dp,
+ .name = &xname,
+ .ppargs = upd->ppargs,
+ };
+ struct xfs_mount *mp = upd->dp->i_mount;
+ xfs_ino_t ino;
+ unsigned int resblks;
+ int error;
+
+ xfs_assert_ilocked(upd->dp, XFS_ILOCK_EXCL);
+
+ /* Check that the name does not already exist in the directory. */
+ xfs_metadir_set_xname(&xname, upd->path, XFS_DIR3_FT_UNKNOWN);
+ error = xfs_metadir_lookup(upd->tp, upd->dp, &xname, &ino);
+ switch (error) {
+ case -ENOENT:
+ break;
+ case 0:
+ error = -EEXIST;
+ fallthrough;
+ default:
+ return error;
+ }
+
+ /*
+ * A newly created regular or special file just has one directory
+ * entry pointing to them, but a directory also the "." entry
+ * pointing to itself.
+ */
+ error = xfs_dialloc(&upd->tp, &args, &ino);
+ if (error)
+ return error;
+ error = xfs_icreate(upd->tp, ino, &args, &upd->ip);
+ if (error)
+ return error;
+ du.ip = upd->ip;
+ xfs_metafile_set_iflag(upd->tp, upd->ip, upd->metafile_type);
+ upd->ip_locked = true;
+
+ /*
+ * Join the directory inode to the transaction. We do not do it
+ * earlier because xfs_dialloc rolls the transaction.
+ */
+ xfs_trans_ijoin(upd->tp, upd->dp, 0);
+
+ /* Create the entry. */
+ if (S_ISDIR(args.mode))
+ resblks = xfs_mkdir_space_res(mp, xname.len);
+ else
+ resblks = xfs_create_space_res(mp, xname.len);
+ xname.type = xfs_mode_to_ftype(args.mode);
+
+ trace_xfs_metadir_try_create(upd);
+
+ error = xfs_dir_create_child(upd->tp, resblks, &du);
+ if (error)
+ return error;
+
+ /* Metadir files are not accounted to quota. */
+
+ trace_xfs_metadir_create(upd);
+
+ return 0;
+}
+
+#ifndef __KERNEL__
+/*
+ * Begin the process of linking a metadata file by allocating transactions
+ * and locking whatever resources we're going to need.
+ */
+int
+xfs_metadir_start_link(
+ struct xfs_metadir_update *upd)
+{
+ struct xfs_mount *mp = upd->dp->i_mount;
+ unsigned int resblks;
+ int nospace_error = 0;
+ int error;
+
+ ASSERT(upd->dp != NULL);
+ ASSERT(upd->ip != NULL);
+ ASSERT(xfs_has_metadir(mp));
+
+ error = xfs_parent_start(mp, &upd->ppargs);
+ if (error)
+ return error;
+
+ resblks = xfs_link_space_res(mp, MAXNAMELEN);
+ error = xfs_trans_alloc_dir(upd->dp, &M_RES(mp)->tr_link, upd->ip,
+ &resblks, &upd->tp, &nospace_error);
+ if (error)
+ goto out_teardown;
+ if (!resblks) {
+ /* We don't allow reservationless updates. */
+ xfs_trans_cancel(upd->tp);
+ upd->tp = NULL;
+ xfs_iunlock(upd->dp, XFS_ILOCK_EXCL);
+ xfs_iunlock(upd->ip, XFS_ILOCK_EXCL);
+ error = nospace_error;
+ goto out_teardown;
+ }
+
+ upd->dp_locked = true;
+ upd->ip_locked = true;
+
+ trace_xfs_metadir_start_link(upd);
+ return 0;
+out_teardown:
+ xfs_metadir_teardown(upd, error);
+ return error;
+}
+
+/*
+ * Link the metadata directory given by @path to the inode @upd->ip.
+ * The path (up to the final component) must already exist, but the final
+ * component must not already exist.
+ */
+int
+xfs_metadir_link(
+ struct xfs_metadir_update *upd)
+{
+ struct xfs_name xname;
+ struct xfs_dir_update du = {
+ .dp = upd->dp,
+ .name = &xname,
+ .ip = upd->ip,
+ .ppargs = upd->ppargs,
+ };
+ struct xfs_mount *mp = upd->dp->i_mount;
+ xfs_ino_t ino;
+ unsigned int resblks;
+ int error;
+
+ xfs_assert_ilocked(upd->dp, XFS_ILOCK_EXCL);
+ xfs_assert_ilocked(upd->ip, XFS_ILOCK_EXCL);
+
+ /* Look up the name in the current directory. */
+ xfs_metadir_set_xname(&xname, upd->path,
+ xfs_mode_to_ftype(VFS_I(upd->ip)->i_mode));
+ error = xfs_metadir_lookup(upd->tp, upd->dp, &xname, &ino);
+ switch (error) {
+ case -ENOENT:
+ break;
+ case 0:
+ error = -EEXIST;
+ fallthrough;
+ default:
+ return error;
+ }
+
+ resblks = xfs_link_space_res(mp, xname.len);
+ error = xfs_dir_add_child(upd->tp, resblks, &du);
+ if (error)
+ return error;
+
+ trace_xfs_metadir_link(upd);
+
+ return 0;
+}
+#endif /* ! __KERNEL__ */
+
+/* Commit a metadir update and unlock/drop all resources. */
+int
+xfs_metadir_commit(
+ struct xfs_metadir_update *upd)
+{
+ int error;
+
+ trace_xfs_metadir_commit(upd);
+
+ error = xfs_trans_commit(upd->tp);
+ upd->tp = NULL;
+
+ xfs_metadir_teardown(upd, error);
+ return error;
+}
+
+/* Cancel a metadir update and unlock/drop all resources. */
+void
+xfs_metadir_cancel(
+ struct xfs_metadir_update *upd,
+ int error)
+{
+ trace_xfs_metadir_cancel(upd);
+
+ xfs_trans_cancel(upd->tp);
+ upd->tp = NULL;
+
+ xfs_metadir_teardown(upd, error);
+}
+
+/* Create a metadata for the last component of the path. */
+int
+xfs_metadir_mkdir(
+ struct xfs_inode *dp,
+ const char *path,
+ struct xfs_inode **ipp)
+{
+ struct xfs_metadir_update upd = {
+ .dp = dp,
+ .path = path,
+ .metafile_type = XFS_METAFILE_DIR,
+ };
+ int error;
+
+ if (xfs_is_shutdown(dp->i_mount))
+ return -EIO;
+
+ /* Allocate a transaction to create the last directory. */
+ error = xfs_metadir_start_create(&upd);
+ if (error)
+ return error;
+
+ /* Create the subdirectory and take our reference. */
+ error = xfs_metadir_create(&upd, S_IFDIR);
+ if (error)
+ goto out_cancel;
+
+ error = xfs_metadir_commit(&upd);
+ if (error)
+ goto out_irele;
+
+ xfs_finish_inode_setup(upd.ip);
+ *ipp = upd.ip;
+ return 0;
+
+out_cancel:
+ xfs_metadir_cancel(&upd, error);
+out_irele:
+ /* Have to finish setting up the inode to ensure it's deleted. */
+ if (upd.ip) {
+ xfs_finish_inode_setup(upd.ip);
+ xfs_irele(upd.ip);
+ }
+ return error;
+}
projects / thirdparty / xfsprogs-dev.git / commitdiff
