'\" t
.\"     Title: jbd2__journal_start
.\"    Author: 
.\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
.\"      Date: September 2017
.\"    Manual: The Linux Journalling API
.\"    Source: Kernel Hackers Manual 4.12.13
.\"  Language: English
.\"
.TH "JBD2__JOURNAL_START" "9" "September 2017" "Kernel Hackers Manual 4\&.12\&" "The Linux Journalling API"
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.SH "NAME"
jbd2__journal_start \- Obtain a new handle\&.
.SH "SYNOPSIS"
.HP \w'handle_t\ *\ jbd2__journal_start('u
.BI "handle_t * jbd2__journal_start(journal_t\ *\ " "journal" ", int\ " "nblocks" ", int\ " "rsv_blocks" ", gfp_t\ " "gfp_mask" ", unsigned\ int\ " "type" ", unsigned\ int\ " "line_no" ");"
.SH "ARGUMENTS"
.PP
\fIjournal_t * journal\fR
.RS 4
Journal to start transaction on\&.
.RE
.PP
\fIint nblocks\fR
.RS 4
number of block buffer we might modify
.RE
.PP
\fIint rsv_blocks\fR
.RS 4
\-\- undescribed \-\-
.RE
.PP
\fIgfp_t gfp_mask\fR
.RS 4
\-\- undescribed \-\-
.RE
.PP
\fIunsigned int type\fR
.RS 4
\-\- undescribed \-\-
.RE
.PP
\fIunsigned int line_no\fR
.RS 4
\-\- undescribed \-\-
.RE
.SH "DESCRIPTION"
.PP
We make sure that the transaction can guarantee at least nblocks of modified buffers in the log\&. We block until the log can guarantee that much space\&. Additionally, if rsv_blocks > 0, we also create another handle with rsv_blocks reserved blocks in the journal\&. This handle is is stored in h_rsv_handle\&. It is not attached to any particular transaction and thus doesn\*(Aqt block transaction commit\&. If the caller uses this reserved handle, it has to set h_rsv_handle to NULL as otherwise
\fBjbd2_journal_stop\fR
on the parent handle will dispose the reserved one\&. Reserved handle has to be converted to a normal handle using
\fBjbd2_journal_start_reserved\fR
before it can be used\&.
.PP
Return a pointer to a newly allocated handle, or an
\fBERR_PTR\fR
value on failure\&.
.SH "AUTHORS"
.PP
\fBRoger Gammans\fR <\&rgammans@computer-surgery.co.uk\&>
.RS 4
Author.
.RE
.PP
\fBStephen Tweedie\fR <\&sct@redhat.com\&>
.RS 4
Author.
.RE
.SH "COPYRIGHT"
.br