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gpfs_next_inode() Subroutine
Name
gpfs_next_inode() - Retrieves the next inode from the inode scan.
Library
GPFS Library (libgpfs.a for AIX, libgpfs.so for Linux)
Synopsis
#include
int gpfs_next_inode(gpfs_iscan_t *iscan,
gpfs_ino_t termIno,
const gpfs_iattr_t **iattr);
Description
The gpfs_next_inode() subroutine obtains the next inode from the specified inode scan and sets the iattr
pointer to the inode’s attributes. The termIno parameter can be used to terminate the inode scan before
the last inode in the file system or snapshot being scanned. A value of 0 may be provided to indicate the
last inode in the file system or snapshot. If there are no more inodes to be returned before the termination
inode, the gpfs_next_inode() subroutine returns a value of 0 and the inode’s attribute pointer is set to
NULL.
For an overview of using gpfs_next_inode() in a backup application, see “Using APIs to develop backup
applications” on page 24.
To generate a full backup, invoke gpfs_open_inodescan() with NULL for the prev_fssnapId parameter.
Repeated invocations of gpfs_next_inode() then return inode information about all existing user files,
directories and links, in inode number order.
To generate an incremental backup, invoke gpfs_next_inode() with the fssnapId that was obtained from
a fssnapHandle at the time the previous backup was created. The snapshot that was used for the
previous backup does not need to exist at the time the incremental backup is generated. That is, the
backup application needs to remember only the fssnapId of the previous backup; the snapshot itself can
be deleted as soon as the backup is completed.
For an incremental backup, only inodes of files that have changed since the specified previous snapshot
will be returned. Any operation that changes the file’s mtime or ctime is considered a change and will
cause the file to be included. Files with no changes to the file’s data or file attributes, other than a change
to atime, are omitted from the scan.
Incremental backups return deleted files, but full backups do not. A deleted file is indicated by the field
ia_nlinks having a value of 0.
Notes:
1. Compile any program that uses this subroutine with the -lgpfs flag from the following library:
v libgpfs.a for AIX
v libgpfs.so for Linux
Parameters
iscan Pointer to the inode scan handle.
termIno The inode scan terminates before this inode number. The caller may specify maxIno from
gpfs_open_inodescan() or zero to scan the entire inode file.
328 GPFS: Administration and Programming Reference