5161a55207
Some block devices, such as LUKS-encrypted volumes mounted via blkmap_crypt, only support read access. When ext4l attempts to write the superblock during mount, the write fails and causes mount to fail. Add a way to detect this read-only device detection: - Test writes during mount by writing back the superblock data; if the write fails, mark the device as read-only - Update bdev_read_only() to return the actual read_only status - Update sb_rdonly() to check the SB_RDONLY flag This allows ext4l to successfully mount read-only devices like LUKS volumes for read access. We could perhaps have a read-only flag in the block device, but that is left for another day. Co-developed-by: Claude <noreply@anthropic.com> Signed-off-by: Simon Glass <simon.glass@canonical.com>
144 lines
2.9 KiB
C
144 lines
2.9 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Filesystem definitions
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*
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* Minimal version for U-Boot ext4l - based on Linux 6.18
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*/
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#ifndef _LINUX_FS_H
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#define _LINUX_FS_H
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#include <linux/types.h>
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#include <linux/list.h>
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#include <linux/mutex.h>
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/* Forward declarations */
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struct inode;
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struct super_block;
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struct buffer_head;
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struct address_space_operations;
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/* errseq_t - error sequence type */
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typedef u32 errseq_t;
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/* fmode_t - file mode type */
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typedef unsigned int fmode_t;
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/* File mode flags */
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#define FMODE_READ ((__force fmode_t)(1 << 0))
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#define FMODE_WRITE ((__force fmode_t)(1 << 1))
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#define FMODE_LSEEK ((__force fmode_t)(1 << 2))
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#define FMODE_NOWAIT ((__force fmode_t)(1 << 20))
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#define FMODE_CAN_ODIRECT ((__force fmode_t)(1 << 21))
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#define FMODE_CAN_ATOMIC_WRITE ((__force fmode_t)(1 << 22))
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/* Seek constants */
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#ifndef SEEK_HOLE
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#define SEEK_HOLE 4
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#define SEEK_DATA 3
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#endif
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/* vfsmount - mount point */
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struct vfsmount {
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struct dentry *mnt_root;
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};
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/* path - pathname components */
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struct path {
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struct vfsmount *mnt;
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struct dentry *dentry;
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};
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/* Buffer operations are in buffer_head.h */
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#ifdef __UBOOT__
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/* Maximum number of cached folios per address_space */
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#define FOLIO_CACHE_MAX 64
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#endif
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/* address_space - extended for inode.c */
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struct address_space {
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struct inode *host;
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errseq_t wb_err;
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unsigned long nrpages;
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unsigned long writeback_index;
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struct list_head i_private_list;
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const struct address_space_operations *a_ops;
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#ifdef __UBOOT__
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/* Simple folio cache for U-Boot (no XA/radix tree) */
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struct folio *folio_cache[FOLIO_CACHE_MAX];
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int folio_cache_count;
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#endif
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};
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/* block_device - minimal stub */
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struct block_device {
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struct address_space *bd_mapping;
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void *bd_disk;
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struct super_block *bd_super;
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dev_t bd_dev;
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bool read_only;
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};
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/* errseq functions - stubs */
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static inline int errseq_check(errseq_t *eseq, errseq_t since)
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{
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return 0;
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}
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static inline int errseq_check_and_advance(errseq_t *eseq, errseq_t *since)
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{
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return 0;
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}
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/* File readahead state - stub */
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struct file_ra_state {
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unsigned long start;
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unsigned int size;
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unsigned int async_size;
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unsigned int ra_pages;
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unsigned int mmap_miss;
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long long prev_pos;
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};
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/* file - minimal stub */
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struct file {
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fmode_t f_mode;
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struct inode *f_inode;
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unsigned int f_flags;
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struct address_space *f_mapping;
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void *private_data;
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struct file_ra_state f_ra;
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struct path f_path;
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loff_t f_pos;
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};
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/* Get inode from file */
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static inline struct inode *file_inode(struct file *f)
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{
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return f->f_inode;
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}
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/* iattr - inode attributes for setattr */
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struct iattr {
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unsigned int ia_valid;
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umode_t ia_mode;
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uid_t ia_uid;
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gid_t ia_gid;
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loff_t ia_size;
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};
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/* writeback_control - defined in linux/compat.h */
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/* fsnotify - stub */
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#define fsnotify_change(d, m) do { } while (0)
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/* inode_init_once - stub */
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static inline void inode_init_once(struct inode *inode)
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{
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}
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/* S_ISDIR, etc. - already in linux/stat.h */
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#include <linux/stat.h>
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#endif /* _LINUX_FS_H */
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