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linux/fs/sysv/sysv.h
Christoph Hellwig f4e420dc42 clean up write_begin usage for directories in pagecache 
For filesystem that implement directories in pagecache we call
block_write_begin with an already allocated page for this code, while the
normal regular file write path uses the default block_write_begin behaviour.

Get rid of the __foofs_write_begin helper and opencode the normal write_begin
call in foofs_write_begin, while adding a new foofs_prepare_chunk helper for
the directory code.  The added benefit is that foofs_prepare_chunk has
a much saner calling convention.

Note that the interruptible flag passed into block_write_begin is always
ignored if we already pass in a page (see next patch for details), and
we never were doing truncations of exessive blocks for this case either so we
can switch directly to block_write_begin_newtrunc.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-08-09 16:47:31 -04:00

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#ifndef _SYSV_H
#define _SYSV_H
#include <linux/buffer_head.h>
typedef __u16 __bitwise __fs16;
typedef __u32 __bitwise __fs32;
#include <linux/sysv_fs.h>
/*
* SystemV/V7/Coherent super-block data in memory
*
* The SystemV/V7/Coherent superblock contains dynamic data (it gets modified
* while the system is running). This is in contrast to the Minix and Berkeley
* filesystems (where the superblock is never modified). This affects the
* sync() operation: we must keep the superblock in a disk buffer and use this
* one as our "working copy".
*/
struct sysv_sb_info {
struct super_block *s_sb; /* VFS superblock */
int s_type; /* file system type: FSTYPE_{XENIX|SYSV|COH} */
char s_bytesex; /* bytesex (le/be/pdp) */
char s_truncate; /* if 1: names > SYSV_NAMELEN chars are truncated */
/* if 0: they are disallowed (ENAMETOOLONG) */
nlink_t s_link_max; /* max number of hard links to a file */
unsigned int s_inodes_per_block; /* number of inodes per block */
unsigned int s_inodes_per_block_1; /* inodes_per_block - 1 */
unsigned int s_inodes_per_block_bits; /* log2(inodes_per_block) */
unsigned int s_ind_per_block; /* number of indirections per block */
unsigned int s_ind_per_block_bits; /* log2(ind_per_block) */
unsigned int s_ind_per_block_2; /* ind_per_block ^ 2 */
unsigned int s_toobig_block; /* 10 + ipb + ipb^2 + ipb^3 */
unsigned int s_block_base; /* physical block number of block 0 */
unsigned short s_fic_size; /* free inode cache size, NICINOD */
unsigned short s_flc_size; /* free block list chunk size, NICFREE */
/* The superblock is kept in one or two disk buffers: */
struct buffer_head *s_bh1;
struct buffer_head *s_bh2;
/* These are pointers into the disk buffer, to compensate for
different superblock layout. */
char * s_sbd1; /* entire superblock data, for part 1 */
char * s_sbd2; /* entire superblock data, for part 2 */
__fs16 *s_sb_fic_count; /* pointer to s_sbd->s_ninode */
sysv_ino_t *s_sb_fic_inodes; /* pointer to s_sbd->s_inode */
__fs16 *s_sb_total_free_inodes; /* pointer to s_sbd->s_tinode */
__fs16 *s_bcache_count; /* pointer to s_sbd->s_nfree */
sysv_zone_t *s_bcache; /* pointer to s_sbd->s_free */
__fs32 *s_free_blocks; /* pointer to s_sbd->s_tfree */
__fs32 *s_sb_time; /* pointer to s_sbd->s_time */
__fs32 *s_sb_state; /* pointer to s_sbd->s_state, only FSTYPE_SYSV */
/* We keep those superblock entities that don't change here;
this saves us an indirection and perhaps a conversion. */
u32 s_firstinodezone; /* index of first inode zone */
u32 s_firstdatazone; /* same as s_sbd->s_isize */
u32 s_ninodes; /* total number of inodes */
u32 s_ndatazones; /* total number of data zones */
u32 s_nzones; /* same as s_sbd->s_fsize */
u16 s_namelen; /* max length of dir entry */
int s_forced_ro;
};
/*
* SystemV/V7/Coherent FS inode data in memory
*/
struct sysv_inode_info {
__fs32 i_data[13];
u32 i_dir_start_lookup;
struct inode vfs_inode;
};
static inline struct sysv_inode_info *SYSV_I(struct inode *inode)
{
return list_entry(inode, struct sysv_inode_info, vfs_inode);
}
static inline struct sysv_sb_info *SYSV_SB(struct super_block *sb)
{
return sb->s_fs_info;
}
/* identify the FS in memory */
enum {
FSTYPE_NONE = 0,
FSTYPE_XENIX,
FSTYPE_SYSV4,
FSTYPE_SYSV2,
FSTYPE_COH,
FSTYPE_V7,
FSTYPE_AFS,
FSTYPE_END,
};
#define SYSV_MAGIC_BASE 0x012FF7B3
#define XENIX_SUPER_MAGIC (SYSV_MAGIC_BASE+FSTYPE_XENIX)
#define SYSV4_SUPER_MAGIC (SYSV_MAGIC_BASE+FSTYPE_SYSV4)
#define SYSV2_SUPER_MAGIC (SYSV_MAGIC_BASE+FSTYPE_SYSV2)
#define COH_SUPER_MAGIC (SYSV_MAGIC_BASE+FSTYPE_COH)
/* Admissible values for i_nlink: 0.._LINK_MAX */
enum {
XENIX_LINK_MAX = 126, /* ?? */
SYSV_LINK_MAX = 126, /* 127? 251? */
V7_LINK_MAX = 126, /* ?? */
COH_LINK_MAX = 10000,
};
static inline void dirty_sb(struct super_block *sb)
{
struct sysv_sb_info *sbi = SYSV_SB(sb);
mark_buffer_dirty(sbi->s_bh1);
if (sbi->s_bh1 != sbi->s_bh2)
mark_buffer_dirty(sbi->s_bh2);
sb->s_dirt = 1;
}
/* ialloc.c */
extern struct sysv_inode *sysv_raw_inode(struct super_block *, unsigned,
struct buffer_head **);
extern struct inode * sysv_new_inode(const struct inode *, mode_t);
extern void sysv_free_inode(struct inode *);
extern unsigned long sysv_count_free_inodes(struct super_block *);
/* balloc.c */
extern sysv_zone_t sysv_new_block(struct super_block *);
extern void sysv_free_block(struct super_block *, sysv_zone_t);
extern unsigned long sysv_count_free_blocks(struct super_block *);
/* itree.c */
extern void sysv_truncate(struct inode *);
extern int sysv_prepare_chunk(struct page *page, loff_t pos, unsigned len);
/* inode.c */
extern struct inode *sysv_iget(struct super_block *, unsigned int);
extern int sysv_write_inode(struct inode *, struct writeback_control *wbc);
extern int sysv_sync_inode(struct inode *);
extern void sysv_set_inode(struct inode *, dev_t);
extern int sysv_getattr(struct vfsmount *, struct dentry *, struct kstat *);
extern int sysv_init_icache(void);
extern void sysv_destroy_icache(void);
/* dir.c */
extern struct sysv_dir_entry *sysv_find_entry(struct dentry *, struct page **);
extern int sysv_add_link(struct dentry *, struct inode *);
extern int sysv_delete_entry(struct sysv_dir_entry *, struct page *);
extern int sysv_make_empty(struct inode *, struct inode *);
extern int sysv_empty_dir(struct inode *);
extern void sysv_set_link(struct sysv_dir_entry *, struct page *,
struct inode *);
extern struct sysv_dir_entry *sysv_dotdot(struct inode *, struct page **);
extern ino_t sysv_inode_by_name(struct dentry *);
extern const struct inode_operations sysv_file_inode_operations;
extern const struct inode_operations sysv_dir_inode_operations;
extern const struct inode_operations sysv_fast_symlink_inode_operations;
extern const struct file_operations sysv_file_operations;
extern const struct file_operations sysv_dir_operations;
extern const struct address_space_operations sysv_aops;
extern const struct super_operations sysv_sops;
extern const struct dentry_operations sysv_dentry_operations;
enum {
BYTESEX_LE,
BYTESEX_PDP,
BYTESEX_BE,
};
static inline u32 PDP_swab(u32 x)
{
#ifdef __LITTLE_ENDIAN
return ((x & 0xffff) << 16) | ((x & 0xffff0000) >> 16);
#else
#ifdef __BIG_ENDIAN
return ((x & 0xff00ff) << 8) | ((x & 0xff00ff00) >> 8);
#else
#error BYTESEX
#endif
#endif
}
static inline __u32 fs32_to_cpu(struct sysv_sb_info *sbi, __fs32 n)
{
if (sbi->s_bytesex == BYTESEX_PDP)
return PDP_swab((__force __u32)n);
else if (sbi->s_bytesex == BYTESEX_LE)
return le32_to_cpu((__force __le32)n);
else
return be32_to_cpu((__force __be32)n);
}
static inline __fs32 cpu_to_fs32(struct sysv_sb_info *sbi, __u32 n)
{
if (sbi->s_bytesex == BYTESEX_PDP)
return (__force __fs32)PDP_swab(n);
else if (sbi->s_bytesex == BYTESEX_LE)
return (__force __fs32)cpu_to_le32(n);
else
return (__force __fs32)cpu_to_be32(n);
}
static inline __fs32 fs32_add(struct sysv_sb_info *sbi, __fs32 *n, int d)
{
if (sbi->s_bytesex == BYTESEX_PDP)
*(__u32*)n = PDP_swab(PDP_swab(*(__u32*)n)+d);
else if (sbi->s_bytesex == BYTESEX_LE)
le32_add_cpu((__le32 *)n, d);
else
be32_add_cpu((__be32 *)n, d);
return *n;
}
static inline __u16 fs16_to_cpu(struct sysv_sb_info *sbi, __fs16 n)
{
if (sbi->s_bytesex != BYTESEX_BE)
return le16_to_cpu((__force __le16)n);
else
return be16_to_cpu((__force __be16)n);
}
static inline __fs16 cpu_to_fs16(struct sysv_sb_info *sbi, __u16 n)
{
if (sbi->s_bytesex != BYTESEX_BE)
return (__force __fs16)cpu_to_le16(n);
else
return (__force __fs16)cpu_to_be16(n);
}
static inline __fs16 fs16_add(struct sysv_sb_info *sbi, __fs16 *n, int d)
{
if (sbi->s_bytesex != BYTESEX_BE)
le16_add_cpu((__le16 *)n, d);
else
be16_add_cpu((__be16 *)n, d);
return *n;
}
#endif /* _SYSV_H */
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