diff options
Diffstat (limited to 'nixpkgs/pkgs/tools/filesystems/squashfs/4k-align.patch')
| -rw-r--r-- | nixpkgs/pkgs/tools/filesystems/squashfs/4k-align.patch | 98 |
1 files changed, 98 insertions, 0 deletions
diff --git a/nixpkgs/pkgs/tools/filesystems/squashfs/4k-align.patch b/nixpkgs/pkgs/tools/filesystems/squashfs/4k-align.patch new file mode 100644 index 000000000000..e73c06788756 --- /dev/null +++ b/nixpkgs/pkgs/tools/filesystems/squashfs/4k-align.patch @@ -0,0 +1,98 @@ +This patch has been edited to apply to squashfs 4.4, commit +52eb4c279cd283ed9802dd1ceb686560b22ffb67. Below is the original +message body of the patch. + +From 7bda7c75748f36b0a50f93e46144d5a4de4974ad Mon Sep 17 00:00:00 2001 +From: Amin Hassani <ahassani@google.com> +Date: Thu, 15 Dec 2016 10:43:15 -0800 +Subject: [PATCH] mksquashfs 4K aligns the files inside the squashfs image + +Files inside a squashfs image are not necessarily 4k (4096) +aligned. This patch starts each file in a 4k aligned address and pads +zero to the end of the file until it reaches the next 4k aligned +address. This will not change the size of the compressed +blocks (especially the last one) and hence it will not change how the +files are being loaded in kernel or unsquashfs. However on average this +increases the size of the squashfs image which can be calculated by the +following formula: + +increased_size = (number_of_unfragmented_files_in_image + number of fragments) * 2048 + +The 4k alignment can be enabled by flag '-4k-align' +--- + squashfs-tools/mksquashfs.c | 16 ++++++++++++++++ + 1 file changed, 16 insertions(+) + +diff --git a/squashfs-tools/mksquashfs.c b/squashfs-tools/mksquashfs.c +index a45b77f..07b1c06 100644 +--- a/squashfs-tools/mksquashfs.c ++++ b/squashfs-tools/mksquashfs.c +@@ -102,7 +102,9 @@ int old_exclude = TRUE; + int use_regex = FALSE; + int nopad = FALSE; + int exit_on_error = FALSE; ++int do_4k_align = FALSE; + long long start_offset = 0; ++#define ALIGN_UP(bytes, size) (bytes = (bytes + size - 1) & ~(size - 1)) + + long long global_uid = -1, global_gid = -1; + +@@ -1546,6 +1548,9 @@ void unlock_fragments() + * queue at this time. + */ + while(!queue_empty(locked_fragment)) { ++ // 4k align the start of remaining queued fragments. ++ if(do_4k_align) ++ ALIGN_UP(bytes, 4096); + write_buffer = queue_get(locked_fragment); + frg = write_buffer->block; + size = SQUASHFS_COMPRESSED_SIZE_BLOCK(fragment_table[frg].size); +@@ -2478,6 +2483,9 @@ void *frag_deflator(void *arg) + write_buffer->size = compressed_size; + pthread_mutex_lock(&fragment_mutex); + if(fragments_locked == FALSE) { ++ // 4k align the start of each fragment. ++ if(do_4k_align) ++ ALIGN_UP(bytes, 4096); + fragment_table[file_buffer->block].size = c_byte; + fragment_table[file_buffer->block].start_block = bytes; + write_buffer->block = bytes; +@@ -2877,6 +2885,10 @@ int write_file_blocks(squashfs_inode *inode, struct dir_ent *dir_ent, + long long sparse = 0; + struct file_buffer *fragment_buffer = NULL; + ++ // 4k align the start of each file. ++ if(do_4k_align) ++ ALIGN_UP(bytes, 4096); ++ + if(pre_duplicate(read_size)) + return write_file_blocks_dup(inode, dir_ent, read_buffer, dup); + +@@ -4972,6 +4984,7 @@ void write_filesystem_tables(struct squashfs_super_block *sBlk, int nopad) + "compressed", no_fragments ? "no" : noF ? "uncompressed" : + "compressed", no_xattrs ? "no" : noX ? "uncompressed" : + "compressed", noI || noId ? "uncompressed" : "compressed"); ++ printf("\t4k %saligned\n", do_4k_align ? "" : "un"); + printf("\tduplicates are %sremoved\n", duplicate_checking ? "" : + "not "); + printf("Filesystem size %.2f Kbytes (%.2f Mbytes)\n", bytes / 1024.0, +@@ -5853,6 +5866,8 @@ print_compressor_options: + root_name = argv[i]; + } else if(strcmp(argv[i], "-version") == 0) { + VERSION(); ++ } else if(strcmp(argv[i], "-4k-align") == 0) { ++ do_4k_align = TRUE; + } else { + ERROR("%s: invalid option\n\n", argv[0]); + printOptions: +@@ -5904,6 +5919,7 @@ printOptions: + ERROR("\t\t\tdirectory containing that directory, " + "rather than the\n"); + ERROR("\t\t\tcontents of the directory\n"); ++ ERROR("-4k-align\t\tenables 4k alignment of all files\n"); + ERROR("\nFilesystem filter options:\n"); + ERROR("-p <pseudo-definition>\tAdd pseudo file " + "definition\n"); +-- +2.23.0 + |