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From: David Howells <dhowells@redhat.com>
To: linux-cachefs@redhat.com
Cc: dhowells@redhat.com, Trond Myklebust <trondmy@hammerspace.com>,
	Anna Schumaker <anna.schumaker@netapp.com>,
	Steve French <sfrench@samba.org>,
	Dominique Martinet <asmadeus@codewreck.org>,
	Jeff Layton <jlayton@kernel.org>,
	Matthew Wilcox <willy@infradead.org>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Omar Sandoval <osandov@osandov.com>,
	JeffleXu <jefflexu@linux.alibaba.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	linux-afs@lists.infradead.org, linux-nfs@vger.kernel.org,
	linux-cifs@vger.kernel.org, ceph-devel@vger.kernel.org,
	v9fs-developer@lists.sourceforge.net,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v2 39/67] cachefiles: Implement a function to get/create a directory in the cache
Date: Thu, 09 Dec 2021 17:02:11 +0000	[thread overview]
Message-ID: <163906933130.143852.962088616746509062.stgit@warthog.procyon.org.uk> (raw)
In-Reply-To: <163906878733.143852.5604115678965006622.stgit@warthog.procyon.org.uk>

Implement a function to get/create structural directories in the cache.
This is used for setting up a cache and creating volume substructures.  The
directory in memory are marked with the S_KERNEL_FILE inode flag whilst
they're in use to tell rmdir to reject attempts to remove them.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819631182.215744.3322471539523262619.stgit@warthog.procyon.org.uk/ # v1
---

 fs/cachefiles/internal.h |    8 +++
 fs/cachefiles/namei.c    |  138 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 146 insertions(+)

diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h
index 3783a3e01027..65e01ac1da39 100644
--- a/fs/cachefiles/internal.h
+++ b/fs/cachefiles/internal.h
@@ -125,6 +125,14 @@ static inline int cachefiles_inject_remove_error(void)
 	return cachefiles_error_injection_state & 2 ? -EIO : 0;
 }
 
+/*
+ * namei.c
+ */
+extern struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
+					       struct dentry *dir,
+					       const char *name);
+extern void cachefiles_put_directory(struct dentry *dir);
+
 /*
  * security.c
  */
diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c
index fef06d2a88ec..25ca41952dab 100644
--- a/fs/cachefiles/namei.c
+++ b/fs/cachefiles/namei.c
@@ -6,6 +6,7 @@
  */
 
 #include <linux/fs.h>
+#include <linux/namei.h>
 #include "internal.h"
 
 /*
@@ -42,3 +43,140 @@ static void __cachefiles_unmark_inode_in_use(struct cachefiles_object *object,
 	inode->i_flags &= ~S_KERNEL_FILE;
 	trace_cachefiles_mark_inactive(object, inode);
 }
+
+/*
+ * get a subdirectory
+ */
+struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
+					struct dentry *dir,
+					const char *dirname)
+{
+	struct dentry *subdir;
+	struct path path;
+	int ret;
+
+	_enter(",,%s", dirname);
+
+	/* search the current directory for the element name */
+	inode_lock_nested(d_inode(dir), I_MUTEX_PARENT);
+
+retry:
+	ret = cachefiles_inject_read_error();
+	if (ret == 0)
+		subdir = lookup_one_len(dirname, dir, strlen(dirname));
+	else
+		subdir = ERR_PTR(ret);
+	if (IS_ERR(subdir)) {
+		trace_cachefiles_vfs_error(NULL, d_backing_inode(dir),
+					   PTR_ERR(subdir),
+					   cachefiles_trace_lookup_error);
+		if (PTR_ERR(subdir) == -ENOMEM)
+			goto nomem_d_alloc;
+		goto lookup_error;
+	}
+
+	_debug("subdir -> %pd %s",
+	       subdir, d_backing_inode(subdir) ? "positive" : "negative");
+
+	/* we need to create the subdir if it doesn't exist yet */
+	if (d_is_negative(subdir)) {
+		ret = cachefiles_has_space(cache, 1, 0);
+		if (ret < 0)
+			goto mkdir_error;
+
+		_debug("attempt mkdir");
+
+		path.mnt = cache->mnt;
+		path.dentry = dir;
+		ret = security_path_mkdir(&path, subdir, 0700);
+		if (ret < 0)
+			goto mkdir_error;
+		ret = cachefiles_inject_write_error();
+		if (ret == 0)
+			ret = vfs_mkdir(&init_user_ns, d_inode(dir), subdir, 0700);
+		if (ret < 0) {
+			trace_cachefiles_vfs_error(NULL, d_inode(dir), ret,
+						   cachefiles_trace_mkdir_error);
+			goto mkdir_error;
+		}
+
+		if (unlikely(d_unhashed(subdir))) {
+			cachefiles_put_directory(subdir);
+			goto retry;
+		}
+		ASSERT(d_backing_inode(subdir));
+
+		_debug("mkdir -> %pd{ino=%lu}",
+		       subdir, d_backing_inode(subdir)->i_ino);
+	}
+
+	/* Tell rmdir() it's not allowed to delete the subdir */
+	inode_lock(d_inode(subdir));
+	inode_unlock(d_inode(dir));
+
+	if (!__cachefiles_mark_inode_in_use(NULL, subdir))
+		goto mark_error;
+
+	inode_unlock(d_inode(subdir));
+
+	/* we need to make sure the subdir is a directory */
+	ASSERT(d_backing_inode(subdir));
+
+	if (!d_can_lookup(subdir)) {
+		pr_err("%s is not a directory\n", dirname);
+		ret = -EIO;
+		goto check_error;
+	}
+
+	ret = -EPERM;
+	if (!(d_backing_inode(subdir)->i_opflags & IOP_XATTR) ||
+	    !d_backing_inode(subdir)->i_op->lookup ||
+	    !d_backing_inode(subdir)->i_op->mkdir ||
+	    !d_backing_inode(subdir)->i_op->rename ||
+	    !d_backing_inode(subdir)->i_op->rmdir ||
+	    !d_backing_inode(subdir)->i_op->unlink)
+		goto check_error;
+
+	_leave(" = [%lu]", d_backing_inode(subdir)->i_ino);
+	return subdir;
+
+check_error:
+	cachefiles_put_directory(subdir);
+	_leave(" = %d [check]", ret);
+	return ERR_PTR(ret);
+
+mark_error:
+	inode_unlock(d_inode(subdir));
+	dput(subdir);
+	return ERR_PTR(-EBUSY);
+
+mkdir_error:
+	inode_unlock(d_inode(dir));
+	dput(subdir);
+	pr_err("mkdir %s failed with error %d\n", dirname, ret);
+	return ERR_PTR(ret);
+
+lookup_error:
+	inode_unlock(d_inode(dir));
+	ret = PTR_ERR(subdir);
+	pr_err("Lookup %s failed with error %d\n", dirname, ret);
+	return ERR_PTR(ret);
+
+nomem_d_alloc:
+	inode_unlock(d_inode(dir));
+	_leave(" = -ENOMEM");
+	return ERR_PTR(-ENOMEM);
+}
+
+/*
+ * Put a subdirectory.
+ */
+void cachefiles_put_directory(struct dentry *dir)
+{
+	if (dir) {
+		inode_lock(dir->d_inode);
+		__cachefiles_unmark_inode_in_use(NULL, dir);
+		inode_unlock(dir->d_inode);
+		dput(dir);
+	}
+}



  parent reply	other threads:[~2021-12-09 17:02 UTC|newest]

Thread overview: 88+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-09 16:53 [PATCH v2 00/67] fscache, cachefiles: Rewrite David Howells
2021-12-09 16:53 ` [PATCH v2 01/67] fscache, cachefiles: Disable configuration David Howells
2021-12-09 16:53 ` [PATCH v2 02/67] cachefiles: Delete the cachefiles driver pending rewrite David Howells
2021-12-09 16:54 ` [PATCH v2 03/67] fscache: Remove the contents of the fscache driver, " David Howells
2021-12-09 16:54 ` [PATCH v2 04/67] netfs: Display the netfs inode number in the netfs_read tracepoint David Howells
2021-12-09 16:54 ` [PATCH v2 05/67] netfs: Pass a flag to ->prepare_write() to say if there's no alloc'd space David Howells
2021-12-09 16:54 ` [PATCH v2 06/67] fscache: Introduce new driver David Howells
2021-12-09 16:54 ` [PATCH v2 07/67] fscache: Implement a hash function David Howells
2021-12-09 17:12   ` Linus Torvalds
2021-12-09 21:57   ` David Howells
2021-12-09 22:07     ` Linus Torvalds
2021-12-10 14:35     ` David Howells
2021-12-10 14:41     ` David Howells
2021-12-10 17:33       ` Linus Torvalds
2021-12-09 16:54 ` [PATCH v2 08/67] fscache: Implement cache registration David Howells
2021-12-14 18:36   ` Jeff Layton
2021-12-09 16:55 ` [PATCH v2 09/67] fscache: Implement volume registration David Howells
2021-12-09 17:32   ` Linus Torvalds
2021-12-14 18:52   ` Jeff Layton
2021-12-14 19:57   ` David Howells
2021-12-09 16:55 ` [PATCH v2 10/67] fscache: Implement cookie registration David Howells
2021-12-09 17:21   ` Linus Torvalds
2021-12-09 16:55 ` [PATCH v2 11/67] fscache: Implement cache-level access helpers David Howells
2021-12-09 16:55 ` [PATCH v2 12/67] fscache: Implement volume-level " David Howells
2021-12-09 16:55 ` [PATCH v2 13/67] fscache: Implement cookie-level " David Howells
2021-12-09 16:56 ` [PATCH v2 14/67] fscache: Implement functions add/remove a cache David Howells
2021-12-09 16:56 ` [PATCH v2 15/67] fscache: Provide and use cache methods to lookup/create/free a volume David Howells
2021-12-09 16:56 ` [PATCH v2 16/67] fscache: Add a function for a cache backend to note an I/O error David Howells
2021-12-09 16:57 ` [PATCH v2 17/67] fscache: Implement simple cookie state machine David Howells
2021-12-09 16:57 ` [PATCH v2 18/67] fscache: Implement cookie user counting and resource pinning David Howells
2021-12-09 16:58 ` [PATCH v2 19/67] fscache: Implement cookie invalidation David Howells
2021-12-09 16:58 ` [PATCH v2 20/67] fscache: Provide a means to begin an operation David Howells
2021-12-09 16:58 ` [PATCH v2 21/67] fscache: Count data storage objects in a cache David Howells
2021-12-09 16:58 ` [PATCH v2 22/67] fscache: Provide read/write stat counters for the cache David Howells
2021-12-09 16:58 ` [PATCH v2 23/67] fscache: Provide a function to let the netfs update its coherency data David Howells
2021-12-09 16:59 ` [PATCH v2 24/67] netfs: Pass more information on how to deal with a hole in the cache David Howells
2021-12-09 16:59 ` [PATCH v2 25/67] fscache: Implement raw I/O interface David Howells
2021-12-09 16:59 ` [PATCH v2 26/67] fscache: Implement higher-level write " David Howells
2021-12-09 16:59 ` [PATCH v2 27/67] vfs, fscache: Implement pinning of cache usage for writeback David Howells
2021-12-09 17:00 ` [PATCH v2 28/67] fscache: Provide a function to note the release of a page David Howells
2021-12-09 17:00 ` [PATCH v2 29/67] fscache: Provide a function to resize a cookie David Howells
2021-12-09 17:00 ` [PATCH v2 30/67] cachefiles: Introduce rewritten driver David Howells
2021-12-09 17:00 ` [PATCH v2 31/67] cachefiles: Define structs David Howells
2021-12-09 17:00 ` [PATCH v2 32/67] cachefiles: Add some error injection support David Howells
2021-12-09 17:01 ` [PATCH v2 33/67] cachefiles: Add a couple of tracepoints for logging errors David Howells
2021-12-09 17:01 ` [PATCH v2 34/67] cachefiles: Add cache error reporting macro David Howells
2021-12-09 17:01 ` [PATCH v2 35/67] cachefiles: Add security derivation David Howells
2021-12-09 17:01 ` [PATCH v2 36/67] cachefiles: Register a miscdev and parse commands over it David Howells
2021-12-09 17:01 ` [PATCH v2 37/67] cachefiles: Provide a function to check how much space there is David Howells
2021-12-09 17:01 ` [PATCH v2 38/67] vfs, cachefiles: Mark a backing file in use with an inode flag David Howells
2021-12-09 17:02 ` David Howells [this message]
2021-12-09 17:02 ` [PATCH v2 40/67] cachefiles: Implement cache registration and withdrawal David Howells
2021-12-09 17:02 ` [PATCH v2 41/67] cachefiles: Implement volume support David Howells
2021-12-09 17:03 ` [PATCH v2 42/67] cachefiles: Add tracepoints for calls to the VFS David Howells
2021-12-09 17:03 ` [PATCH v2 43/67] cachefiles: Implement object lifecycle funcs David Howells
2021-12-09 17:03 ` [PATCH v2 44/67] cachefiles: Implement key to filename encoding David Howells
2021-12-09 17:03 ` [PATCH v2 45/67] cachefiles: Implement metadata/coherency data storage in xattrs David Howells
2021-12-09 17:03 ` [PATCH v2 46/67] cachefiles: Mark a backing file in use with an inode flag David Howells
2021-12-09 17:04 ` [PATCH v2 47/67] cachefiles: Implement culling daemon commands David Howells
2021-12-09 17:04 ` [PATCH v2 48/67] cachefiles: Implement backing file wrangling David Howells
2021-12-09 17:05 ` [PATCH v2 49/67] cachefiles: Implement begin and end I/O operation David Howells
2021-12-09 17:05 ` [PATCH v2 50/67] cachefiles: Implement cookie resize for truncate David Howells
2021-12-09 17:05 ` [PATCH v2 51/67] cachefiles: Implement the I/O routines David Howells
2021-12-09 17:06 ` [PATCH v2 52/67] cachefiles: Allow cachefiles to actually function David Howells
2021-12-09 17:06 ` [PATCH v2 53/67] fscache, cachefiles: Display stats of no-space events David Howells
2021-12-09 17:06 ` [PATCH v2 54/67] fscache, cachefiles: Display stat of culling events David Howells
2021-12-09 17:07 ` [PATCH v2 55/67] afs: Handle len being extending over page end in write_begin/write_end David Howells
2021-12-09 17:08 ` [PATCH v2 56/67] afs: Fix afs_write_end() to handle len > page size David Howells
2021-12-09 17:08 ` [PATCH v2 57/67] afs: Convert afs to use the new fscache API David Howells
2021-12-09 17:08 ` [PATCH v2 58/67] afs: Copy local writes to the cache when writing to the server David Howells
2021-12-09 17:08 ` [PATCH v2 59/67] afs: Skip truncation on the server of data we haven't written yet David Howells
2021-12-09 17:09 ` [PATCH v2 60/67] 9p: Use fscache indexing rewrite and reenable caching David Howells
2021-12-09 17:09 ` [PATCH v2 61/67] 9p: Copy local writes to the cache when writing to the server David Howells
2021-12-09 17:09 ` [PATCH v2 62/67] nfs: Convert to new fscache volume/cookie API David Howells
2021-12-11 13:22   ` David Wysochanski
2021-12-11 13:37   ` David Howells
2021-12-09 17:10 ` [PATCH v2 63/67] nfs: Implement cache I/O by accessing the cache directly David Howells
2021-12-09 17:10 ` [PATCH v2 64/67] cifs: Support fscache indexing rewrite (untested) David Howells
2021-12-09 17:10 ` [PATCH v2 65/67] ceph: conversion to new fscache API David Howells
2021-12-09 17:10 ` [PATCH v2 66/67] ceph: add fscache writeback support David Howells
2021-12-09 17:11 ` [PATCH v2 67/67] fscache: Rewrite documentation David Howells
2021-12-10 18:38 ` [PATCH v2 00/67] fscache, cachefiles: Rewrite David Wysochanski
2021-12-11 13:44   ` David Wysochanski
2021-12-13 15:41   ` [PATCH] fscache: Need to go round again after processing LRU_DISCARDING state David Howells
2021-12-13 21:05     ` David Wysochanski
2021-12-13 16:22   ` David Howells
2021-12-13 20:03   ` David Howells
2021-12-13 22:39   ` David Howells

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