107 lines
3.0 KiB
C
107 lines
3.0 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#include <linux/fs.h>
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#include <linux/qnx4_fs.h>
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#define QNX4_DEBUG 0
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#if QNX4_DEBUG
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#define QNX4DEBUG(X) printk X
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#else
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#define QNX4DEBUG(X) (void) 0
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#endif
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struct qnx4_sb_info {
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unsigned int Version; /* may be useful */
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struct qnx4_inode_entry *BitMap; /* useful */
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};
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struct qnx4_inode_info {
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struct qnx4_inode_entry raw;
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loff_t mmu_private;
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struct inode vfs_inode;
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};
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extern struct inode *qnx4_iget(struct super_block *, unsigned long);
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extern struct dentry *qnx4_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags);
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extern unsigned long qnx4_count_free_blocks(struct super_block *sb);
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extern unsigned long qnx4_block_map(struct inode *inode, long iblock);
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extern const struct inode_operations qnx4_dir_inode_operations;
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extern const struct file_operations qnx4_dir_operations;
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extern int qnx4_is_free(struct super_block *sb, long block);
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static inline struct qnx4_sb_info *qnx4_sb(struct super_block *sb)
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{
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return sb->s_fs_info;
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}
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static inline struct qnx4_inode_info *qnx4_i(struct inode *inode)
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{
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return container_of(inode, struct qnx4_inode_info, vfs_inode);
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}
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static inline struct qnx4_inode_entry *qnx4_raw_inode(struct inode *inode)
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{
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return &qnx4_i(inode)->raw;
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}
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/*
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* A qnx4 directory entry is an inode entry or link info
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* depending on the status field in the last byte. The
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* first byte is where the name start either way, and a
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* zero means it's empty.
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*
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* Also, due to a bug in gcc, we don't want to use the
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* real (differently sized) name arrays in the inode and
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* link entries, but always the 'de_name[]' one in the
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* fake struct entry.
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*
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* See
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*
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* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99578#c6
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*
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* for details, but basically gcc will take the size of the
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* 'name' array from one of the used union entries randomly.
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*
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* This use of 'de_name[]' (48 bytes) avoids the false positive
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* warnings that would happen if gcc decides to use 'inode.di_name'
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* (16 bytes) even when the pointer and size were to come from
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* 'link.dl_name' (48 bytes).
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*
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* In all cases the actual name pointer itself is the same, it's
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* only the gcc internal 'what is the size of this field' logic
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* that can get confused.
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*/
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union qnx4_directory_entry {
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struct {
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const char de_name[48];
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u8 de_pad[15];
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u8 de_status;
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};
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struct qnx4_inode_entry inode;
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struct qnx4_link_info link;
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};
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static inline const char *get_entry_fname(union qnx4_directory_entry *de,
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int *size)
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{
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/* Make sure the status byte is in the same place for all structs. */
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BUILD_BUG_ON(offsetof(struct qnx4_inode_entry, di_status) !=
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offsetof(struct qnx4_link_info, dl_status));
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BUILD_BUG_ON(offsetof(struct qnx4_inode_entry, di_status) !=
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offsetof(union qnx4_directory_entry, de_status));
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if (!de->de_name[0])
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return NULL;
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if (!(de->de_status & (QNX4_FILE_USED|QNX4_FILE_LINK)))
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return NULL;
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if (!(de->de_status & QNX4_FILE_LINK))
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*size = sizeof(de->inode.di_fname);
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else
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*size = sizeof(de->link.dl_fname);
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*size = strnlen(de->de_name, *size);
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return de->de_name;
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}
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