/* * memfd test file-system * This file uses FUSE to create a dummy file-system with only one file /memfd. * This file is read-only and takes 1s per read. * * This file-system is used by the memfd test-cases to force the kernel to pin * pages during reads(). Due to the 1s delay of this file-system, this is a * nice way to test race-conditions against get_user_pages() in the kernel. * * We use direct_io==1 to force the kernel to use direct-IO for this * file-system. */ #define FUSE_USE_VERSION 26 #include #include #include #include #include #include static const char memfd_content[] = "memfd-example-content"; static const char memfd_path[] = "/memfd"; static int memfd_getattr(const char *path, struct stat *st) { memset(st, 0, sizeof(*st)); if (!strcmp(path, "/")) { st->st_mode = S_IFDIR | 0755; st->st_nlink = 2; } else if (!strcmp(path, memfd_path)) { st->st_mode = S_IFREG | 0444; st->st_nlink = 1; st->st_size = strlen(memfd_content); } else { return -ENOENT; } return 0; } static int memfd_readdir(const char *path, void *buf, fuse_fill_dir_t filler, off_t offset, struct fuse_file_info *fi) { if (strcmp(path, "/")) return -ENOENT; filler(buf, ".", NULL, 0); filler(buf, "..", NULL, 0); filler(buf, memfd_path + 1, NULL, 0); return 0; } static int memfd_open(const char *path, struct fuse_file_info *fi) { if (strcmp(path, memfd_path)) return -ENOENT; if ((fi->flags & 3) != O_RDONLY) return -EACCES; /* force direct-IO */ fi->direct_io = 1; return 0; } static int memfd_read(const char *path, char *buf, size_t size, off_t offset, struct fuse_file_info *fi) { size_t len; if (strcmp(path, memfd_path) != 0) return -ENOENT; sleep(1); len = strlen(memfd_content); if (offset < len) { if (offset + size > len) size = len - offset; memcpy(buf, memfd_content + offset, size); } else { size = 0; } return size; } static struct fuse_operations memfd_ops = { .getattr = memfd_getattr, .readdir = memfd_readdir, .open = memfd_open, .read = memfd_read, }; int main(int argc, char *argv[]) { return fuse_main(argc, argv, &memfd_ops, NULL); }
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authorJan Kara <jack@suse.cz>2016-08-10 17:22:44 +0200
committerDan Williams <dan.j.williams@intel.com>2016-12-26 20:29:24 -0800
commitc6dcf52c23d2d3fb5235cec42d7dd3f786b87d55 (patch)
tree7e63a6c0225a769e679b194f54b5723e4cfba385 /tools/lib/api
parente568df6b84ff05a22467503afc11bee7a6ba0700 (diff)
mm: Invalidate DAX radix tree entries only if appropriate
Currently invalidate_inode_pages2_range() and invalidate_mapping_pages() just delete all exceptional radix tree entries they find. For DAX this is not desirable as we track cache dirtiness in these entries and when they are evicted, we may not flush caches although it is necessary. This can for example manifest when we write to the same block both via mmap and via write(2) (to different offsets) and fsync(2) then does not properly flush CPU caches when modification via write(2) was the last one. Create appropriate DAX functions to handle invalidation of DAX entries for invalidate_inode_pages2_range() and invalidate_mapping_pages() and wire them up into the corresponding mm functions. Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'tools/lib/api')