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file_meta_ops.h
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file_meta_ops.h
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#ifndef mgridfs_file_meta_ops_h
#define mgridfs_file_meta_ops_h
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fuse.h>
namespace mgridfs {
/** Get file attributes.
*
* Similar to stat(). The 'st_dev' and 'st_blksize' fields are
* ignored. The 'st_ino' field is ignored except if the 'use_ino'
* mount option is given.
*/
int mgridfs_getattr(const char*, struct stat*);
/**
* Get attributes from an open file
*
* This method is called instead of the getattr() method if the
* file information is available.
*
* Currently this is only called after the create() method if that
* is implemented (see above). Later it may be called for
* invocations of fstat() too.
*
* Introduced in version 2.5
*/
int mgridfs_fgetattr(const char *, struct stat *, struct fuse_file_info *);
/** Read the target of a symbolic link
*
* The buffer should be filled with a null terminated string. The
* buffer size argument includes the space for the terminating
* null character. If the linkname is too long to fit in the
* buffer, it should be truncated. The return value should be 0
* for success.
*/
int mgridfs_readlink(const char *, char *, size_t);
/** Create a file node
*
* This is called for creation of all non-directory, non-symlink
* nodes. If the filesystem defines a create() method, then for
* regular files that will be called instead.
*/
int mgridfs_mknod(const char *, mode_t, dev_t);
/** Remove a file */
int mgridfs_unlink(const char *);
/** Create a symbolic link */
int mgridfs_symlink(const char *, const char *);
/** Rename a file */
int mgridfs_rename(const char *, const char *);
/** Create a hard link to a file */
int mgridfs_link(const char *, const char *);
/** Change the permission bits of a file */
int mgridfs_chmod(const char *, mode_t);
/** Change the owner and group of a file */
int mgridfs_chown(const char *, uid_t, gid_t);
/** Change the size of a file */
int mgridfs_truncate(const char *, off_t);
/** Change the access and/or modification times of a file
*
* Deprecated, use utimens() instead.
*/
int mgridfs_utime(const char *, struct utimbuf *);
/** File open operation
*
* No creation (O_CREAT, O_EXCL) and by default also no
* truncation (O_TRUNC) flags will be passed to open(). If an
* application specifies O_TRUNC, fuse first calls truncate()
* and then open(). Only if 'atomic_o_trunc' has been
* specified and kernel version is 2.6.24 or later, O_TRUNC is
* passed on to open.
*
* Unless the 'default_permissions' mount option is given,
* open should check if the operation is permitted for the
* given flags. Optionally open may also return an arbitrary
* filehandle in the fuse_file_info structure, which will be
* passed to all file operations.
*
* Changed in version 2.2
*/
int mgridfs_open(const char *, struct fuse_file_info *);
/** Read data from an open file
*
* Read should return exactly the number of bytes requested except
* on EOF or error, otherwise the rest of the data will be
* substituted with zeroes. An exception to this is when the
* 'direct_io' mount option is specified, in which case the return
* value of the read system call will reflect the return value of
* this operation.
*
* Changed in version 2.2
*/
int mgridfs_read(const char *, char *, size_t, off_t, struct fuse_file_info *);
/** Store data from an open file in a buffer
*
* Similar to the read() method, but data is stored and
* returned in a generic buffer.
*
* No actual copying of data has to take place, the source
* file descriptor may simply be stored in the buffer for
* later data transfer.
*
* The buffer must be allocated dynamically and stored at the
* location pointed to by bufp. If the buffer contains memory
* regions, they too must be allocated using malloc(). The
* allocated memory will be freed by the caller.
*
* Introduced in version 2.9
*/
int mgridfs_read_buf(const char *, struct fuse_bufvec **bufp, size_t size, off_t off, struct fuse_file_info *);
/** Write data to an open file
*
* Write should return exactly the number of bytes requested
* except on error. An exception to this is when the 'direct_io'
* mount option is specified (see read operation).
*
* Changed in version 2.2
*/
int mgridfs_write(const char *, const char *, size_t, off_t, struct fuse_file_info *);
/** Write contents of buffer to an open file
*
* Similar to the write() method, but data is supplied in a
* generic buffer. Use fuse_buf_copy() to transfer data to
* the destination.
*
* Introduced in version 2.9
*/
int mgridfs_write_buf(const char *, struct fuse_bufvec *buf, off_t off, struct fuse_file_info *);
/** Possibly flush cached data
*
* BIG NOTE: This is not equivalent to fsync(). It's not a
* request to sync dirty data.
*
* Flush is called on each close() of a file descriptor. So if a
* filesystem wants to return write errors in close() and the file
* has cached dirty data, this is a good place to write back data
* and return any errors. Since many applications ignore close()
* errors this is not always useful.
*
* NOTE: The flush() method may be called more than once for each
* open(). This happens if more than one file descriptor refers
* to an opened file due to dup(), dup2() or fork() calls. It is
* not possible to determine if a flush is final, so each flush
* should be treated equally. Multiple write-flush sequences are
* relatively rare, so this shouldn't be a problem.
*
* Filesystems shouldn't assume that flush will always be called
* after some writes, or that if will be called at all.
*
* Changed in version 2.2
*/
int mgridfs_flush(const char *, struct fuse_file_info *);
/** Release an open file
*
* Release is called when there are no more references to an open
* file: all file descriptors are closed and all memory mappings
* are unmapped.
*
* For every open() call there will be exactly one release() call
* with the same flags and file descriptor. It is possible to
* have a file opened more than once, in which case only the last
* release will mean, that no more reads/writes will happen on the
* file. The return value of release is ignored.
*
* Changed in version 2.2
*/
int mgridfs_release(const char *, struct fuse_file_info *);
/** Synchronize file contents
*
* If the datasync parameter is non-zero, then only the user data
* should be flushed, not the meta data.
*
* Changed in version 2.2
*/
int mgridfs_fsync(const char *, int, struct fuse_file_info *);
/** Set extended attributes */
int mgridfs_setxattr(const char *, const char *, const char *, size_t, int);
/** Get extended attributes */
int mgridfs_getxattr(const char *, const char *, char *, size_t);
/** List extended attributes */
int mgridfs_listxattr(const char *, char *, size_t);
/** Remove extended attributes */
int mgridfs_removexattr(const char *, const char *);
/**
* Create and open a file
*
* If the file does not exist, first create it with the specified
* mode, and then open it.
*
* If this method is not implemented or under Linux kernel
* versions earlier than 2.6.15, the mknod() and open() methods
* will be called instead.
*
* Introduced in version 2.5
*/
int mgridfs_create(const char *, mode_t, struct fuse_file_info *);
/**
* Change the size of an open file
*
* This method is called instead of the truncate() method if the
* truncation was invoked from an ftruncate() system call.
*
* If this method is not implemented or under Linux kernel
* versions earlier than 2.6.15, the truncate() method will be
* called instead.
*
* Introduced in version 2.5
*/
int mgridfs_ftruncate(const char *, off_t, struct fuse_file_info *);
/**
* Perform POSIX file locking operation
*
* The cmd argument will be either F_GETLK, F_SETLK or F_SETLKW.
*
* For the meaning of fields in 'struct flock' see the man page
* for fcntl(2). The l_whence field will always be set to
* SEEK_SET.
*
* For checking lock ownership, the 'fuse_file_info->owner'
* argument must be used.
*
* For F_GETLK operation, the library will first check currently
* held locks, and if a conflicting lock is found it will return
* information without calling this method. This ensures, that
* for local locks the l_pid field is correctly filled in. The
* results may not be accurate in case of race conditions and in
* the presence of hard links, but it's unlikely that an
* application would rely on accurate GETLK results in these
* cases. If a conflicting lock is not found, this method will be
* called, and the filesystem may fill out l_pid by a meaningful
* value, or it may leave this field zero.
*
* For F_SETLK and F_SETLKW the l_pid field will be set to the pid
* of the process performing the locking operation.
*
* Note: if this method is not implemented, the kernel will still
* allow file locking to work locally. Hence it is only
* interesting for network filesystems and similar.
*
* Introduced in version 2.6
*/
int mgridfs_lock(const char *, struct fuse_file_info *, int cmd, struct flock *);
/**
* Change the access and modification times of a file with
* nanosecond resolution
*
* This supersedes the old utime() interface. New applications
* should use this.
*
* See the utimensat(2) man page for details.
*
* Introduced in version 2.6
*/
int mgridfs_utimens(const char *, const struct timespec tv[2]);
/**
* Map block index within file to block index within device
*
* Note: This makes sense only for block device backed filesystems
* mounted with the 'blkdev' option
*
* Introduced in version 2.6
*/
int mgridfs_bmap(const char *, size_t blocksize, uint64_t *idx);
/**
* Ioctl
*
* flags will have FUSE_IOCTL_COMPAT set for 32bit ioctls in
* 64bit environment. The size and direction of data is
* determined by _IOC_*() decoding of cmd. For _IOC_NONE,
* data will be NULL, for _IOC_WRITE data is out area, for
* _IOC_READ in area and if both are set in/out area. In all
* non-NULL cases, the area is of _IOC_SIZE(cmd) bytes.
*
* Introduced in version 2.8
*/
int mgridfs_ioctl(const char *, int cmd, void *arg, struct fuse_file_info *, unsigned int flags, void *data);
/**
* Poll for IO readiness events
*
* Note: If ph is non-NULL, the client should notify
* when IO readiness events occur by calling
* fuse_notify_poll() with the specified ph.
*
* Regardless of the number of times poll with a non-NULL ph
* is received, single notification is enough to clear all.
* Notifying more times incurs overhead but doesn't harm
* correctness.
*
* The callee is responsible for destroying ph with
* fuse_pollhandle_destroy() when no longer in use.
*
* Introduced in version 2.8
*/
int mgridfs_poll(const char *, struct fuse_file_info *, struct fuse_pollhandle *ph, unsigned *reventsp);
/**
* Perform BSD file locking operation
*
* The op argument will be either LOCK_SH, LOCK_EX or LOCK_UN
*
* Nonblocking requests will be indicated by ORing LOCK_NB to
* the above operations
*
* For more information see the flock(2) manual page.
*
* Additionally fi->owner will be set to a value unique to
* this open file. This same value will be supplied to
* ->release() when the file is released.
*
* Note: if this method is not implemented, the kernel will still
* allow file locking to work locally. Hence it is only
* interesting for network filesystems and similar.
*
* Introduced in version 2.9
*/
int mgridfs_flock(const char *, struct fuse_file_info *, int op);
/**
* Allocates space for an open file
*
* This function ensures that required space is allocated for specified
* file. If this function returns success then any subsequent write
* request to specified range is guaranteed not to fail because of lack
* of space on the file system media.
*
* Introduced in version 2.9.1
*/
int mgridfs_fallocate(const char *, int, off_t, off_t, struct fuse_file_info *);
}
#endif