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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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21fc61c73c
kmap() in page_follow_link_light() needed to go - allowing to hold an arbitrary number of kmaps for long is a great way to deadlocking the system. new helper (inode_nohighmem(inode)) needs to be used for pagecache symlinks inodes; done for all in-tree cases. page_follow_link_light() instrumented to yell about anything missed. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
53 lines
1.1 KiB
C
53 lines
1.1 KiB
C
/*
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* symlink.c
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*
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* Copyright (c) 1999 Al Smith
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*
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* Portions derived from work (c) 1995,1996 Christian Vogelgsang.
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*/
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#include <linux/string.h>
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#include <linux/pagemap.h>
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#include <linux/buffer_head.h>
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#include "efs.h"
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static int efs_symlink_readpage(struct file *file, struct page *page)
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{
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char *link = page_address(page);
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struct buffer_head * bh;
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struct inode * inode = page->mapping->host;
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efs_block_t size = inode->i_size;
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int err;
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err = -ENAMETOOLONG;
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if (size > 2 * EFS_BLOCKSIZE)
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goto fail;
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/* read first 512 bytes of link target */
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err = -EIO;
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bh = sb_bread(inode->i_sb, efs_bmap(inode, 0));
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if (!bh)
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goto fail;
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memcpy(link, bh->b_data, (size > EFS_BLOCKSIZE) ? EFS_BLOCKSIZE : size);
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brelse(bh);
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if (size > EFS_BLOCKSIZE) {
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bh = sb_bread(inode->i_sb, efs_bmap(inode, 1));
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if (!bh)
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goto fail;
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memcpy(link + EFS_BLOCKSIZE, bh->b_data, size - EFS_BLOCKSIZE);
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brelse(bh);
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}
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link[size] = '\0';
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SetPageUptodate(page);
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unlock_page(page);
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return 0;
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fail:
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SetPageError(page);
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unlock_page(page);
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return err;
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}
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const struct address_space_operations efs_symlink_aops = {
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.readpage = efs_symlink_readpage
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};
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