1PAGECACHE_ISIZE_EXTE(9)   Memory Management in Linux   PAGECACHE_ISIZE_EXTE(9)
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NAME

6       pagecache_isize_extended - update pagecache after extension of i_size
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SYNOPSIS

9       void pagecache_isize_extended(struct inode * inode, loff_t from,
10                                     loff_t to);
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ARGUMENTS

13       inode
14           inode for which i_size was extended
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16       from
17           original inode size
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19       to
20           new inode size
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DESCRIPTION

23       Handle extension of inode size either caused by extending truncate or
24       by write starting after current i_size. We mark the page straddling
25       current i_size RO so that page_mkwrite is called on the nearest write
26       access to the page. This way filesystem can be sure that page_mkwrite
27       is called on the page before user writes to the page via mmap after the
28       i_size has been changed.
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30       The function must be called after i_size is updated so that page fault
31       coming after we unlock the page will already see the new i_size. The
32       function must be called while we still hold i_mutex - this not only
33       makes sure i_size is stable but also that userspace cannot observe new
34       i_size value before we are prepared to store mmap writes at new inode
35       size.
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38Kernel Hackers Manual 2.6.         June 2019           PAGECACHE_ISIZE_EXTE(9)
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