/*
 *  linux/fs/nfs/symlink.c
 *
 *  Copyright (C) 1992  Rick Sladkey
 *
 *  Optimization changes Copyright (C) 1994 Florian La Roche
 *
 *  Jun 7 1999, cache symlink lookups in the page cache.  -DaveM
 *
 *  nfs symlink handling code
 */

#include <linux/time.h>
#include <linux/errno.h>
#include <linux/sunrpc/clnt.h>
#include <linux/nfs.h>
#include <linux/nfs2.h>
#include <linux/nfs_fs.h>
#include <linux/pagemap.h>
#include <linux/stat.h>
#include <linux/mm.h>
#include <linux/string.h>

/* Symlink caching in the page cache is even more simplistic
 * and straight-forward than readdir caching.
 */

static int nfs_symlink_filler(struct inode *inode, struct page *page)
{
	int error;

	error = NFS_PROTO(inode)->readlink(inode, page, 0, PAGE_SIZE);
	if (error < 0)
		goto error;
	SetPageUptodate(page);
	unlock_page(page);
	return 0;

error:
	SetPageError(page);
	unlock_page(page);
	return -EIO;
}

static const char *nfs_get_link(struct dentry *dentry,
				struct inode *inode,
				struct delayed_call *done)
{
	struct page *page;
	void *err;

	if (!dentry) {
		err = ERR_PTR(nfs_revalidate_mapping_rcu(inode));
		if (err)
			return err;
		page = find_get_page(inode->i_mapping, 0);
		if (!page)
			return ERR_PTR(-ECHILD);
		if (!PageUptodate(page)) {
			put_page(page);
			return ERR_PTR(-ECHILD);
		}
	} else {
		err = ERR_PTR(nfs_revalidate_mapping(inode, inode->i_mapping));
		if (err)
			return err;
		page = read_cache_page(&inode->i_data, 0,
					(filler_t *)nfs_symlink_filler, inode);
		if (IS_ERR(page))
			return ERR_CAST(page);
	}
	set_delayed_call(done, page_put_link, page);
	return page_address(page);
}

/*
 * symlinks can't do much...
 */
const struct inode_operations nfs_symlink_inode_operations = {
	.get_link	= nfs_get_link,
	.getattr	= nfs_getattr,
	.setattr	= nfs_setattr,
};
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<div class='path'>path: <a href='/cgit.cgi/linux/net-next.git/log/?h=nds-private-remove&amp;id=926af6273fc683cd98cd0ce7bf0d04a02eed6742'>root</a>/<a href='/cgit.cgi/linux/net-next.git/log/include?h=nds-private-remove&amp;id=926af6273fc683cd98cd0ce7bf0d04a02eed6742'>include</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/cgit.cgi/linux/net-next.git/log/include?h=nds-private-remove&amp;id=926af6273fc683cd98cd0ce7bf0d04a02eed6742&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th><th class='left'>Files</th><th class='left'>Lines</th></tr>
<tr><td><span title='2017-02-07 12:10:57 -0800'>2017-02-07</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/include?h=nds-private-remove&amp;id=926af6273fc683cd98cd0ce7bf0d04a02eed6742'>Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net</a></td><td>Linus Torvalds</td><td>3</td><td><span class='deletions'>-7</span>/<span class='insertions'>+10</span></td></tr>
<tr><td><span title='2017-02-07 11:19:00 -0500'>2017-02-07</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/include?h=nds-private-remove&amp;id=69629464e0b587f3711739b3aa2bcdaf2e075276'>udp: properly cope with csum errors</a></td><td>Eric Dumazet</td><td>1</td><td><span class='deletions'>-1</span>/<span class='insertions'>+3</span></td></tr>
<tr><td><span title='2017-02-04 19:44:22 -0500'>2017-02-04</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/include?h=nds-private-remove&amp;id=d71b7896886345c53ef1d84bda2bc758554f5d61'>netlabel: out of bound access in cipso_v4_validate()</a></td><td>Eric Dumazet</td><td>1</td><td><span class='deletions'>-0</span>/<span class='insertions'>+4</span></td></tr>
<tr><td><span title='2017-02-04 12:18:01 -0800'>2017-02-04</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/include?h=nds-private-remove&amp;id=a572a1b999489efb591287632279c6c9eca3e4ed'>Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/ker...</a></td><td>Linus Torvalds</td><td>1</td><td><span class='deletions'>-0</span>/<span class='insertions'>+17</span></td></tr>
<tr><td><span title='2017-02-04 10:44:15 -0800'>2017-02-04</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/include?h=nds-private-remove&amp;id=412e6d3fec247b2bc83106514b0fb3b17e2eb7fe'>Merge tag 'char-misc-4.10-rc7' of git://git.kernel.org/pub/scm/linux/kernel/g...</a></td><td>Linus Torvalds</td><td>1</td><td><span class='deletions'>-2</span>/<span class='insertions'>+30</span></td></tr>
<tr><td><span title='2017-02-03 14:13:19 -0800'>2017-02-03</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/include?h=nds-private-remove&amp;id=a96dfddbcc04336bbed50dc2b24823e45e09e80c'>base/memory, hotplug: fix a kernel oops in show_valid_zones()</a></td><td>Toshi Kani</td><td>1</td><td><span class='deletions'>-1</span>/<span class='insertions'>+2</span></td></tr>
<tr><td><span title='2017-02-03 11:32:25 -0800'>2017-02-03</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/include?h=nds-private-remove&amp;id=79c9089f97d37ffac88c3ddb6d359b2cf75058b7'>Merge tag 'drm-fixes-for-v4.10-rc7' of git://people.freedesktop.org/~airlied/...</a></td><td>Linus Torvalds</td><td>2</td><td><span class='deletions'>-1</span>/<span class='insertions'>+16</span></td></tr>
<tr><td><span title='2017-02-03 10:30:27 -0800'>2017-02-03</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/include?h=nds-private-remove&amp;id=2cb54ce9ee92ae627bc1cef8bea236905910a86d'>Merge branch 'modversions' (modversions fixes for powerpc from Ard)</a></td><td>Linus Torvalds</td><td>3</td><td><span class='deletions'>-17</span>/<span class='insertions'>+25</span></td></tr>
<tr><td><span title='2017-02-03 09:56:43 -0800'>2017-02-03</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/include?h=nds-private-remove&amp;id=29905b52fad0854351f57bab867647e4982285bf'>log2: make order_base_2() behave correctly on const input value zero</a></td><td>Ard Biesheuvel</td><td>1</td><td><span class='deletions'>-1</span>/<span class='insertions'>+12</span></td></tr>
<tr><td><span title='2017-02-03 08:28:25 -0800'>2017-02-03</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/include?h=nds-private-remove&amp;id=4b9eee96fcb361a5e16a8d2619825e8a048f81f7'>module: unify absolute krctab definitions for 32-bit and 64-bit</a></td><td>Ard Biesheuvel</td><td>1</td><td><span class='deletions'>-7</span>/<span class='insertions'>+0</span></td></tr>
<tr><td><span title='2017-02-03 08:28:25 -0800'>2017-02-03</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/include?h=nds-private-remove&amp;id=71810db27c1c853b335675bee335d893bc3d324b'>modversions: treat symbol CRCs as 32 bit quantities</a></td><td>Ard Biesheuvel</td><td>3</td><td><span class='deletions'>-12</span>/<span class='insertions'>+27</span></td></tr>
<tr><td><span title='2017-02-03 11:05:23 -0500'>2017-02-03</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/include?h=nds-private-remove&amp;id=013e8167899d389075160412a8c0c5e0581e1f13'>ipv6: sr: remove cleanup flag and fix HMAC computation</a></td><td>David Lebrun</td><td>1</td><td><span class='deletions'>-6</span>/<span class='insertions'>+3</span></td></tr>
<tr><td><span title='2017-02-02 13:30:19 -0800'>2017-02-02</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/include?h=nds-private-remove&amp;id=891aa1e0f13c3aaa756c69b343d6ab6f3357009b'>Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/ke...</a></td><td>Linus Torvalds</td><td>1</td><td><span class='deletions'>-3</span>/<span class='insertions'>+0</span></td></tr>
<tr><td><span title='2017-02-01 11:52:27 -0800'>2017-02-01</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/include?h=nds-private-remove&amp;id=6d04dfc8966019b8b0977b2cb942351f13d2b178'>Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net</a></td><td>Linus Torvalds</td><td>4</td><td><span class='deletions'>-19</span>/<span class='insertions'>+26</span></td></tr>
<tr><td><span title='2017-02-01 10:30:56 -0800'>2017-02-01</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/include?h=nds-private-remove&amp;id=2883aaea363f7a897ff06d2e6c73ae7aae285bcb'>Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/vir...</a></td><td>Linus Torvalds</td><td>1</td><td><span class='deletions'>-0</span>/<span class='insertions'>+1</span></td></tr>
<tr><td><span title='2017-02-01 12:10:56 -0500'>2017-02-01</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/include?h=nds-private-remove&amp;id=1a2a14444d32b89b28116daea86f63ced1716668'>net: fix ndo_features_check/ndo_fix_features comment ordering</a></td><td>Dimitris Michailidis</td><td>1</td><td><span class='deletions'>-14</span>/<span class='insertions'>+15</span></td></tr>
<tr><td><span title='2017-02-01 08:37:27 +0100'>2017-02-01</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/include?h=nds-private-remove&amp;id=fff4b87e594ad3d2e4f51e8d3d86a6f9d3d8b654'>perf/x86/intel/uncore: Make package handling more robust</a></td><td>Thomas Gleixner</td><td>1</td><td><span class='deletions'>-2</span>/<span class='insertions'>+0</span></td></tr>