![Artem Bityutskiy](/assets/img/avatar_default.png)
It does not look like sysv FS needs 'write_super()' at all, because all it does is a timestamp update. I cannot test this patch, because this file-system is so old and probably has not been used by anyone for years, so there are no tools to create it in Linux. But from the code I see that marking the superblock as dirty is basically marking the superblock buffers as drity and then setting the s_dirt flag. And when 'write_super()' is executed to handle the s_dirt flag, we just update the timestamp and again mark the superblock buffer as dirty. Seems pointless. It looks like we can update the timestamp more opprtunistically - on unmount or remount of sync, and nothing should change. Thus, this patch removes 'sysv_write_super()' and 's_dirt'. Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
247 lines
7.7 KiB
C
247 lines
7.7 KiB
C
#ifndef _SYSV_H
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#define _SYSV_H
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#include <linux/buffer_head.h>
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typedef __u16 __bitwise __fs16;
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typedef __u32 __bitwise __fs32;
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#include <linux/sysv_fs.h>
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/*
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* SystemV/V7/Coherent super-block data in memory
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*
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* The SystemV/V7/Coherent superblock contains dynamic data (it gets modified
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* while the system is running). This is in contrast to the Minix and Berkeley
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* filesystems (where the superblock is never modified). This affects the
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* sync() operation: we must keep the superblock in a disk buffer and use this
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* one as our "working copy".
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*/
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struct sysv_sb_info {
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struct super_block *s_sb; /* VFS superblock */
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int s_type; /* file system type: FSTYPE_{XENIX|SYSV|COH} */
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char s_bytesex; /* bytesex (le/be/pdp) */
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char s_truncate; /* if 1: names > SYSV_NAMELEN chars are truncated */
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/* if 0: they are disallowed (ENAMETOOLONG) */
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unsigned int s_inodes_per_block; /* number of inodes per block */
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unsigned int s_inodes_per_block_1; /* inodes_per_block - 1 */
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unsigned int s_inodes_per_block_bits; /* log2(inodes_per_block) */
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unsigned int s_ind_per_block; /* number of indirections per block */
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unsigned int s_ind_per_block_bits; /* log2(ind_per_block) */
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unsigned int s_ind_per_block_2; /* ind_per_block ^ 2 */
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unsigned int s_toobig_block; /* 10 + ipb + ipb^2 + ipb^3 */
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unsigned int s_block_base; /* physical block number of block 0 */
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unsigned short s_fic_size; /* free inode cache size, NICINOD */
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unsigned short s_flc_size; /* free block list chunk size, NICFREE */
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/* The superblock is kept in one or two disk buffers: */
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struct buffer_head *s_bh1;
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struct buffer_head *s_bh2;
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/* These are pointers into the disk buffer, to compensate for
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different superblock layout. */
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char * s_sbd1; /* entire superblock data, for part 1 */
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char * s_sbd2; /* entire superblock data, for part 2 */
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__fs16 *s_sb_fic_count; /* pointer to s_sbd->s_ninode */
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sysv_ino_t *s_sb_fic_inodes; /* pointer to s_sbd->s_inode */
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__fs16 *s_sb_total_free_inodes; /* pointer to s_sbd->s_tinode */
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__fs16 *s_bcache_count; /* pointer to s_sbd->s_nfree */
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sysv_zone_t *s_bcache; /* pointer to s_sbd->s_free */
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__fs32 *s_free_blocks; /* pointer to s_sbd->s_tfree */
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__fs32 *s_sb_time; /* pointer to s_sbd->s_time */
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__fs32 *s_sb_state; /* pointer to s_sbd->s_state, only FSTYPE_SYSV */
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/* We keep those superblock entities that don't change here;
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this saves us an indirection and perhaps a conversion. */
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u32 s_firstinodezone; /* index of first inode zone */
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u32 s_firstdatazone; /* same as s_sbd->s_isize */
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u32 s_ninodes; /* total number of inodes */
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u32 s_ndatazones; /* total number of data zones */
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u32 s_nzones; /* same as s_sbd->s_fsize */
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u16 s_namelen; /* max length of dir entry */
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int s_forced_ro;
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};
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/*
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* SystemV/V7/Coherent FS inode data in memory
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*/
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struct sysv_inode_info {
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__fs32 i_data[13];
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u32 i_dir_start_lookup;
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struct inode vfs_inode;
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};
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static inline struct sysv_inode_info *SYSV_I(struct inode *inode)
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{
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return list_entry(inode, struct sysv_inode_info, vfs_inode);
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}
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static inline struct sysv_sb_info *SYSV_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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/* identify the FS in memory */
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enum {
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FSTYPE_NONE = 0,
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FSTYPE_XENIX,
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FSTYPE_SYSV4,
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FSTYPE_SYSV2,
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FSTYPE_COH,
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FSTYPE_V7,
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FSTYPE_AFS,
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FSTYPE_END,
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};
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#define SYSV_MAGIC_BASE 0x012FF7B3
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#define XENIX_SUPER_MAGIC (SYSV_MAGIC_BASE+FSTYPE_XENIX)
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#define SYSV4_SUPER_MAGIC (SYSV_MAGIC_BASE+FSTYPE_SYSV4)
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#define SYSV2_SUPER_MAGIC (SYSV_MAGIC_BASE+FSTYPE_SYSV2)
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#define COH_SUPER_MAGIC (SYSV_MAGIC_BASE+FSTYPE_COH)
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/* Admissible values for i_nlink: 0.._LINK_MAX */
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enum {
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XENIX_LINK_MAX = 126, /* ?? */
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SYSV_LINK_MAX = 126, /* 127? 251? */
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V7_LINK_MAX = 126, /* ?? */
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COH_LINK_MAX = 10000,
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};
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static inline void dirty_sb(struct super_block *sb)
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{
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struct sysv_sb_info *sbi = SYSV_SB(sb);
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mark_buffer_dirty(sbi->s_bh1);
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if (sbi->s_bh1 != sbi->s_bh2)
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mark_buffer_dirty(sbi->s_bh2);
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}
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/* ialloc.c */
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extern struct sysv_inode *sysv_raw_inode(struct super_block *, unsigned,
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struct buffer_head **);
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extern struct inode * sysv_new_inode(const struct inode *, umode_t);
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extern void sysv_free_inode(struct inode *);
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extern unsigned long sysv_count_free_inodes(struct super_block *);
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/* balloc.c */
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extern sysv_zone_t sysv_new_block(struct super_block *);
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extern void sysv_free_block(struct super_block *, sysv_zone_t);
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extern unsigned long sysv_count_free_blocks(struct super_block *);
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/* itree.c */
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extern void sysv_truncate(struct inode *);
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extern int sysv_prepare_chunk(struct page *page, loff_t pos, unsigned len);
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/* inode.c */
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extern struct inode *sysv_iget(struct super_block *, unsigned int);
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extern int sysv_write_inode(struct inode *, struct writeback_control *wbc);
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extern int sysv_sync_inode(struct inode *);
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extern void sysv_set_inode(struct inode *, dev_t);
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extern int sysv_getattr(struct vfsmount *, struct dentry *, struct kstat *);
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extern int sysv_init_icache(void);
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extern void sysv_destroy_icache(void);
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/* dir.c */
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extern struct sysv_dir_entry *sysv_find_entry(struct dentry *, struct page **);
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extern int sysv_add_link(struct dentry *, struct inode *);
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extern int sysv_delete_entry(struct sysv_dir_entry *, struct page *);
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extern int sysv_make_empty(struct inode *, struct inode *);
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extern int sysv_empty_dir(struct inode *);
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extern void sysv_set_link(struct sysv_dir_entry *, struct page *,
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struct inode *);
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extern struct sysv_dir_entry *sysv_dotdot(struct inode *, struct page **);
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extern ino_t sysv_inode_by_name(struct dentry *);
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extern const struct inode_operations sysv_file_inode_operations;
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extern const struct inode_operations sysv_dir_inode_operations;
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extern const struct inode_operations sysv_fast_symlink_inode_operations;
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extern const struct file_operations sysv_file_operations;
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extern const struct file_operations sysv_dir_operations;
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extern const struct address_space_operations sysv_aops;
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extern const struct super_operations sysv_sops;
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extern const struct dentry_operations sysv_dentry_operations;
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enum {
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BYTESEX_LE,
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BYTESEX_PDP,
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BYTESEX_BE,
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};
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static inline u32 PDP_swab(u32 x)
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{
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#ifdef __LITTLE_ENDIAN
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return ((x & 0xffff) << 16) | ((x & 0xffff0000) >> 16);
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#else
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#ifdef __BIG_ENDIAN
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return ((x & 0xff00ff) << 8) | ((x & 0xff00ff00) >> 8);
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#else
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#error BYTESEX
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#endif
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#endif
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}
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static inline __u32 fs32_to_cpu(struct sysv_sb_info *sbi, __fs32 n)
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{
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if (sbi->s_bytesex == BYTESEX_PDP)
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return PDP_swab((__force __u32)n);
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else if (sbi->s_bytesex == BYTESEX_LE)
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return le32_to_cpu((__force __le32)n);
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else
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return be32_to_cpu((__force __be32)n);
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}
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static inline __fs32 cpu_to_fs32(struct sysv_sb_info *sbi, __u32 n)
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{
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if (sbi->s_bytesex == BYTESEX_PDP)
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return (__force __fs32)PDP_swab(n);
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else if (sbi->s_bytesex == BYTESEX_LE)
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return (__force __fs32)cpu_to_le32(n);
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else
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return (__force __fs32)cpu_to_be32(n);
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}
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static inline __fs32 fs32_add(struct sysv_sb_info *sbi, __fs32 *n, int d)
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{
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if (sbi->s_bytesex == BYTESEX_PDP)
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*(__u32*)n = PDP_swab(PDP_swab(*(__u32*)n)+d);
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else if (sbi->s_bytesex == BYTESEX_LE)
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le32_add_cpu((__le32 *)n, d);
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else
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be32_add_cpu((__be32 *)n, d);
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return *n;
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}
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static inline __u16 fs16_to_cpu(struct sysv_sb_info *sbi, __fs16 n)
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{
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if (sbi->s_bytesex != BYTESEX_BE)
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return le16_to_cpu((__force __le16)n);
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else
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return be16_to_cpu((__force __be16)n);
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}
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static inline __fs16 cpu_to_fs16(struct sysv_sb_info *sbi, __u16 n)
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{
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if (sbi->s_bytesex != BYTESEX_BE)
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return (__force __fs16)cpu_to_le16(n);
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else
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return (__force __fs16)cpu_to_be16(n);
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}
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static inline __fs16 fs16_add(struct sysv_sb_info *sbi, __fs16 *n, int d)
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{
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if (sbi->s_bytesex != BYTESEX_BE)
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le16_add_cpu((__le16 *)n, d);
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else
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be16_add_cpu((__be16 *)n, d);
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return *n;
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}
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#endif /* _SYSV_H */
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