ext4_extent_idx<\/strong>\uff1a\u6307\u5411\u4e0b\u7ea7\u8282\u70b9\u7684\u7d22\u5f15\u8282\u70b9\u3002<\/li>\n<\/ul>\n\u5bf9\u4e8e\u5c0f\u6587\u4ef6\uff0ci_block \u53ef\u5bb9\u7eb3\u4e00\u4e2a\u5934\u90e8\u548c\u6700\u591a\u56db\u4e2a\u6269\u5c55\uff0c\u6bcf\u4e2a\u6269\u5c55\u53ef\u5bfb\u5740 128MB\u3002\u5bf9\u4e8e\u5927\u6587\u4ef6\uff0c\u521b\u5efa\u591a\u7ea7\u6269\u5c55\u6811\uff0c\u4e00\u4e2a 4KB \u5757\u53ef\u5bb9\u7eb3 340 \u4e2a\u6269\u5c55\uff0c\u652f\u6301\u9ad8\u8fbe 42.5GB \u7684\u6587\u4ef6\u3002\u66f4\u5927\u7684\u6587\u4ef6\u901a\u8fc7\u589e\u52a0\u6811\u6df1\u5ea6\u5904\u7406\u3002<\/p>\n
\u6e90\u7801\u8def\u5f84<\/strong>\uff1ainclude\/linux\/ext4_fs.h<\/p>\n\u793a\u4f8b<\/strong>\uff1a<\/p>\n\n
\n
c<\/div>\n
\n
\n
<\/div>\n<\/div>\n<\/div>\n
\n
<\/code><\/p>\n\n
\n
struct ext4_extent_header {<\/div>\n
__le16 eh_magic; \/* \u683c\u5f0f\u6807\u8bc6\u7b26 *\/<\/div>\n
__le16 eh_entries; \/* \u6709\u6548\u6761\u76ee\u6570 *\/<\/div>\n
__le16 eh_max; \/* \u6700\u5927\u6761\u76ee\u5bb9\u91cf *\/<\/div>\n
__le16 eh_depth; \/* \u6811\u6df1\u5ea6 *\/<\/div>\n
__le32 eh_generation; \/* \u6811\u751f\u6210\u6807\u8bc6 *\/<\/div>\n
};<\/div>\n
<\/div>\n
struct ext4_extent {<\/div>\n
__le32 ee_block; \/* \u7b2c\u4e00\u4e2a\u903b\u8f91\u5757 *\/<\/div>\n
__le16 ee_len; \/* \u5757\u6570 *\/<\/div>\n
__le16 ee_start_hi; \/* \u7269\u7406\u5757\u9ad8 16 \u4f4d *\/<\/div>\n
__le32 ee_start_lo; \/* \u7269\u7406\u5757\u4f4e 32 \u4f4d *\/<\/div>\n
};<\/div>\n
<\/div>\n
struct ext4_extent_idx {<\/div>\n
__le32 ei_block; \/* \u903b\u8f91\u5757\u7d22\u5f15 *\/<\/div>\n
__le32 ei_leaf_lo; \/* \u6307\u5411\u4e0b\u4e00\u7ea7\u7684\u6307\u9488 *\/<\/div>\n
__le16 ei_leaf_hi; \/* \u7269\u7406\u5757\u9ad8 16 \u4f4d *\/<\/div>\n
__u16 ei_unused;<\/div>\n
};<\/div>\n<\/div>\n<\/div>\n<\/div>\n
<\/div>\n
<\/div>\n<\/div>\n<\/div>\n
\u7d22\u5f15\u8282\u70b9\u5206\u914d<\/h4>\n
\u7d22\u5f15\u8282\u70b9\u901a\u8fc7\u4f4d\u56fe\u7ba1\u7406\uff0c\u8ddf\u8e2a\u7a7a\u95f2\u548c\u5df2\u5206\u914d\u7684\u8282\u70b9\u3002ext4_new_inode \u51fd\u6570\u5b9a\u4f4d\u4e0b\u4e00\u4e2a\u7a7a\u95f2\u7d22\u5f15\u8282\u70b9\uff1a<\/p>\n
\n
\n
c<\/div>\n
\n
\n
<\/div>\n<\/div>\n<\/div>\n
\n
<\/code><\/p>\n\n
\n
struct inode *ext4_new_inode(…) {<\/div>\n
…<\/div>\n
inode_bitmap_bh = ext4_read_inode_bitmap(sb, group);<\/div>\n
ino = ext4_find_next_zero_bit((unsigned long *)inode_bitmap_bh->b_data,<\/div>\n
EXT4_INODES_PER_GROUP(sb), ino);<\/div>\n
…<\/div>\n
}<\/div>\n<\/div>\n<\/div>\n<\/div>\n
<\/div>\n
<\/div>\n<\/div>\n<\/div>\n
2. \u6587\u4ef6\u7cfb\u7edf\u7ed3\u6784<\/h3>\n
ext4 \u6587\u4ef6\u7cfb\u7edf\u57fa\u4e8e\u7d22\u5f15\u8282\u70b9\u548c\u5757\uff0c\u7ec4\u7ec7\u6210\u66f4\u9ad8\u5c42\u6b21\u7684\u7ed3\u6784\uff1a<\/p>\n
\n- \u5757\u7ec4<\/strong>\uff1a\u5b58\u50a8\u5355\u5143\uff0c\u7531 ext4_group_desc \u5b9a\u4e49\uff0c\u5305\u542b\uff1a\n
\n- bg_block_bitmap_lo\uff1a\u5757\u4f4d\u56fe\u3002<\/li>\n
- bg_inode_bitmap_lo\uff1a\u7d22\u5f15\u8282\u70b9\u4f4d\u56fe\u3002<\/li>\n
- bg_inode_table_lo\uff1a\u7d22\u5f15\u8282\u70b9\u8868\u3002<\/li>\n<\/ul>\n<\/li>\n
- \u5757\u7ec4\u63cf\u8ff0\u7b26\u8868<\/strong>\uff1a\u591a\u4e2a\u5757\u7ec4\u63cf\u8ff0\u7b26\u7684\u96c6\u5408\u3002<\/li>\n
- \u8d85\u7ea7\u5757<\/strong>\uff1a\u5b58\u50a8\u5168\u5c40\u6587\u4ef6\u7cfb\u7edf\u5143\u6570\u636e\uff08ext4_super_block\uff09\uff0c\u5305\u62ec\uff1a\n
\n- \u603b\u7d22\u5f15\u8282\u70b9\u6570\uff08s_inodes_count\uff09\u3002<\/li>\n
- \u603b\u5757\u6570\uff08s_blocks_count_lo\uff09\u3002<\/li>\n
- \u6bcf\u4e2a\u5757\u7ec4\u7684\u7d22\u5f15\u8282\u70b9\u6570\uff08s_inodes_per_group\uff09\u3002<\/li>\n
- \u6bcf\u4e2a\u5757\u7ec4\u7684\u5757\u6570\uff08s_blocks_per_group\uff09\u3002<\/li>\n<\/ul>\n<\/li>\n
- \u5f15\u5bfc\u5757<\/strong>\uff1a\u5728\u7b2c\u4e00\u4e2a\u5757\u7ec4\u4e2d\u9884\u7559 1KB \u7528\u4e8e\u5f15\u5bfc\u52a0\u8f7d\u7a0b\u5e8f\u3002<\/li>\n<\/ul>\n
\u5907\u4efd\u7b56\u7565<\/strong>\uff1a<\/p>\n\n- \u9ed8\u8ba4<\/strong>\uff1a\u6bcf\u4e2a\u5757\u7ec4\u5b58\u50a8\u8d85\u7ea7\u5757\u548c\u63cf\u8ff0\u7b26\u8868\u5907\u4efd\u3002<\/li>\n
- \u7a00\u758f\u8d85\u7ea7\u5757\uff08Sparse Super\uff09<\/strong>\uff1a\u4ec5\u5728\u5757\u7ec4\u7d22\u5f15 0\u30013\u30015\u30017 \u53ca\u5176\u5e42\u6b21\u5b58\u50a8\u5907\u4efd\u3002<\/li>\n
- \u5143\u5757\u7ec4\uff08Meta Block Groups\uff09<\/strong>\uff1a\u5c06\u5757\u7ec4\u5206\u4e3a\u6bcf\u7ec4 64 \u4e2a\u7684\u5143\u5757\u7ec4\uff0c\u6bcf\u4e2a\u5143\u5757\u7ec4\u7684\u63cf\u8ff0\u7b26\u8868\u4ec5\u5305\u542b\u81ea\u8eab\u5185\u5bb9\uff0c\u6700\u591a 64 \u9879\uff0c\u4f18\u5316\u7a7a\u95f4\u4f7f\u7528\uff0c\u7c7b\u4f3c\u4e8e Merkle \u6811\u3002<\/li>\n<\/ul>\n
3. \u76ee\u5f55\u5b58\u50a8<\/h3>\n
\u76ee\u5f55\u662f\u5177\u6709\u7d22\u5f15\u8282\u70b9\u7684\u7279\u6b8a\u6587\u4ef6\uff0c\u5176\u5757\u5b58\u50a8\u6587\u4ef6\u5143\u6570\u636e\uff08ext4_dir_entry_2\uff09\uff1a<\/p>\n
\n
\n
<\/div>\n<\/div>\n
\n\n\n| \u5b57\u6bb5<\/th>\n | \u63cf\u8ff0<\/th>\n<\/tr>\n<\/thead>\n |
\n\n| inode<\/td>\n | \u6587\u4ef6\u7684\u7d22\u5f15\u8282\u70b9\u53f7<\/td>\n<\/tr>\n |
\n| rec_len<\/td>\n | \u6761\u76ee\u957f\u5ea6<\/td>\n<\/tr>\n |
\n| name_len<\/td>\n | \u6587\u4ef6\u540d\u957f\u5ea6<\/td>\n<\/tr>\n |
\n| file_type<\/td>\n | \u6587\u4ef6\u7c7b\u578b\uff08\u5982\u5e38\u89c4\u6587\u4ef6\u3001\u76ee\u5f55\uff09<\/td>\n<\/tr>\n |
\n| name<\/td>\n | \u6587\u4ef6\u540d\uff08\u6700\u5927 EXT4_NAME_LEN\uff09<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n\n- \u7ebf\u6027\u5b58\u50a8<\/strong>\uff1a\u6761\u76ee\u4ee5\u5217\u8868\u5f62\u5f0f\u5b58\u50a8\uff0c\u9996\u4e24\u6761\u76ee\u4e3a .\uff08\u5f53\u524d\u76ee\u5f55\uff09\u548c ..\uff08\u4e0a\u7ea7\u76ee\u5f55\uff09\u3002<\/li>\n
- \u7d22\u5f15\u5b58\u50a8<\/strong>\uff1a\u5bf9\u4e8e\u5927\u76ee\u5f55\uff0c\u8bbe\u7f6e EXT4_INDEX_FL \u6807\u5fd7\u542f\u7528\u57fa\u4e8e\u54c8\u5e0c\u7684\u7d22\u5f15\u6811\uff08dx_root\uff09\uff1a\n
\n- dx_root_info\uff1a\u8ddf\u8e2a\u7d22\u5f15\u5c42\u7ea7\uff08indirect_levels\uff09\u3002<\/li>\n
- dx_entry\uff1a\u6587\u4ef6\u540d\u54c8\u5e0c\u4e0e\u6570\u636e\u5757\u7684\u6620\u5c04\u3002<\/li>\n
- \u53f6\u5b50\u8282\u70b9\u5305\u542b ext4_dir_entry_2 \u5217\u8868\uff0c\u652f\u6301\u5feb\u901f\u67e5\u627e\u3002<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n
\u6e90\u7801\u8def\u5f84<\/strong>\uff1ainclude\/linux\/ext4_fs.h<\/p>\n4. \u8f6f\u94fe\u63a5\u4e0e\u786c\u94fe\u63a5<\/h3>\n\n- \u786c\u94fe\u63a5<\/strong>\uff1a\n
\n- \u4e0e\u539f\u59cb\u6587\u4ef6\u5171\u4eab\u540c\u4e00\u7d22\u5f15\u8282\u70b9\u3002<\/li>\n
- \u53d7\u9650\u4e8e\u540c\u4e00\u6587\u4ef6\u7cfb\u7edf\uff08\u7d22\u5f15\u8282\u70b9\u4e3a\u6587\u4ef6\u7cfb\u7edf\u7279\u6709\uff09\u3002<\/li>\n
- \u4f7f\u7528 ln source target \u521b\u5efa\u3002<\/li>\n<\/ul>\n<\/li>\n
- \u8f6f\u94fe\u63a5<\/strong>\uff1a\n
\n- \u5177\u6709\u72ec\u7acb\u7d22\u5f15\u8282\u70b9\uff0c\u6307\u5411\u53e6\u4e00\u6587\u4ef6\u7684\u8def\u5f84\u3002<\/li>\n
- \u652f\u6301\u8de8\u6587\u4ef6\u7cfb\u7edf\u94fe\u63a5\u3002<\/li>\n
- \u5373\u4f7f\u76ee\u6807\u6587\u4ef6\u88ab\u5220\u9664\uff0c\u94fe\u63a5\u6587\u4ef6\u4ecd\u5b58\u5728\uff08\u6210\u4e3a\u60ac\u7a7a\u94fe\u63a5\uff09\u3002<\/li>\n
- \u4f7f\u7528 ln -s source target \u521b\u5efa\u3002<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n
\u7ed3\u8bba<\/h2>\n\u4ee5 ext4 \u4e3a\u4ee3\u8868\u7684 Linux \u6587\u4ef6\u7cfb\u7edf\u56f4\u7ed5\u7d22\u5f15\u8282\u70b9\u6784\u5efa\uff0c\u901a\u8fc7\u7d22\u5f15\u8282\u70b9\u7ba1\u7406\u6587\u4ef6\u5143\u6570\u636e\u548c\u5757\u6307\u9488\uff0cext4 \u901a\u8fc7\u6269\u5c55\uff08extents\uff09\u63d0\u5347\u4e86\u5927\u6587\u4ef6\u6027\u80fd\u3002\u5757\u7ec4\u3001\u8d85\u7ea7\u5757\u548c\u63cf\u8ff0\u7b26\u8868\u7b49\u9ad8\u7ea7\u7ed3\u6784\u786e\u4fdd\u4e86\u9ad8\u6548\u7684\u5b58\u50a8\u548c\u7ba1\u7406\u3002\u76ee\u5f55\u901a\u8fc7\u7ebf\u6027\u6216\u7d22\u5f15\u5b58\u50a8\u5b9e\u73b0\u5feb\u901f\u67e5\u627e\uff0c\u94fe\u63a5\u5219\u63d0\u4f9b\u4e86\u7075\u6d3b\u7684\u6587\u4ef6\u5f15\u7528\u65b9\u5f0f\u3002\u8fd9\u4e00\u67b6\u6784\u4f53\u73b0\u4e86 Linux \u5728\u6587\u4ef6\u7ba1\u7406\u65b9\u9762\u7684\u5f3a\u5927\u4e0e\u53ef\u6269\u5c55\u6027\uff0c\u5bf9\u5f00\u53d1\u8005\u548c\u7ba1\u7406\u5458\u81f3\u5173\u91cd\u8981\u3002<\/p>\n","protected":false},"excerpt":{"rendered":" \u672c\u6587\u6df1\u5165\u63a2\u8ba8\u4e86 Linux \u6587\u4ef6...<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4924],"tags":[],"class_list":["post-208382","post","type-post","status-publish","format-standard","hentry","category-setup-tutorials"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/208382","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=208382"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/208382\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=208382"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=208382"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=208382"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}} |