1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #include <linux/fs.h> 3 #include <linux/qnx4_fs.h> 4 5 #define QNX4_DEBUG 0 6 7 #if QNX4_DEBUG 8 #define QNX4DEBUG(X) printk X 9 #else 10 #define QNX4DEBUG(X) (void) 0 11 #endif 12 13 struct qnx4_sb_info { 14 unsigned int Version; /* may be useful */ 15 struct qnx4_inode_entry *BitMap; /* useful */ 16 }; 17 18 struct qnx4_inode_info { 19 struct qnx4_inode_entry raw; 20 loff_t mmu_private; 21 struct inode vfs_inode; 22 }; 23 24 extern struct inode *qnx4_iget(struct super_block *, unsigned long); 25 extern struct dentry *qnx4_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags); 26 extern unsigned long qnx4_count_free_blocks(struct super_block *sb); 27 extern unsigned long qnx4_block_map(struct inode *inode, long iblock); 28 29 extern const struct inode_operations qnx4_dir_inode_operations; 30 extern const struct file_operations qnx4_dir_operations; 31 extern int qnx4_is_free(struct super_block *sb, long block); 32 33 static inline struct qnx4_sb_info *qnx4_sb(struct super_block *sb) 34 { 35 return sb->s_fs_info; 36 } 37 38 static inline struct qnx4_inode_info *qnx4_i(struct inode *inode) 39 { 40 return container_of(inode, struct qnx4_inode_info, vfs_inode); 41 } 42 43 static inline struct qnx4_inode_entry *qnx4_raw_inode(struct inode *inode) 44 { 45 return &qnx4_i(inode)->raw; 46 } 47 48 /* 49 * A qnx4 directory entry is an inode entry or link info 50 * depending on the status field in the last byte. The 51 * first byte is where the name start either way, and a 52 * zero means it's empty. 53 * 54 * Also, due to a bug in gcc, we don't want to use the 55 * real (differently sized) name arrays in the inode and 56 * link entries, but always the 'de_name[]' one in the 57 * fake struct entry. 58 * 59 * See 60 * 61 * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99578#c6 62 * 63 * for details, but basically gcc will take the size of the 64 * 'name' array from one of the used union entries randomly. 65 * 66 * This use of 'de_name[]' (48 bytes) avoids the false positive 67 * warnings that would happen if gcc decides to use 'inode.di_name' 68 * (16 bytes) even when the pointer and size were to come from 69 * 'link.dl_name' (48 bytes). 70 * 71 * In all cases the actual name pointer itself is the same, it's 72 * only the gcc internal 'what is the size of this field' logic 73 * that can get confused. 74 */ 75 union qnx4_directory_entry { 76 struct { 77 const char de_name[48]; 78 u8 de_pad[15]; 79 u8 de_status; 80 }; 81 struct qnx4_inode_entry inode; 82 struct qnx4_link_info link; 83 }; 84 85 static inline const char *get_entry_fname(union qnx4_directory_entry *de, 86 int *size) 87 { 88 /* Make sure the status byte is in the same place for all structs. */ 89 BUILD_BUG_ON(offsetof(struct qnx4_inode_entry, di_status) != 90 offsetof(struct qnx4_link_info, dl_status)); 91 BUILD_BUG_ON(offsetof(struct qnx4_inode_entry, di_status) != 92 offsetof(union qnx4_directory_entry, de_status)); 93 94 if (!de->de_name[0]) 95 return NULL; 96 if (!(de->de_status & (QNX4_FILE_USED|QNX4_FILE_LINK))) 97 return NULL; 98 if (!(de->de_status & QNX4_FILE_LINK)) 99 *size = sizeof(de->inode.di_fname); 100 else 101 *size = sizeof(de->link.dl_fname); 102 103 *size = strnlen(de->de_name, *size); 104 105 return de->de_name; 106 } 107