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Revision 7bf811a595a895b7a886dcf218d0d34f97df76dc authored by Josef Bacik on 08 October 2013, 02:11:09 UTC, committed by Chris Mason on 11 October 2013, 01:27:56 UTC 
Btrfs: limit delalloc pages outside of find_delalloc_range
 
Liu fixed part of this problem and unfortunately I steered him in slightly the
wrong direction and so didn't completely fix the problem.  The problem is we
limit the size of the delalloc range we are looking for to max bytes and then we
try to lock that range.  If we fail to lock the pages in that range we will
shrink the max bytes to a single page and re loop.  However if our first page is
inside of the delalloc range then we will end up limiting the end of the range
to a period before our first page.  This is illustrated below

[0 -------- delalloc range --------- 256mb]
                                  [page]

So find_delalloc_range will return with delalloc_start as 0 and end as 128mb,
and then we will notice that delalloc_start < *start and adjust it up, but not
adjust delalloc_end up, so things go sideways.  To fix this we need to not limit
the max bytes in find_delalloc_range, but in find_lock_delalloc_range and that
way we don't end up with this confusion.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
1 parent 4871c15
Raw File
xattr.h 
/*
  File: linux/xattr.h

  Extended attributes handling.

  Copyright (C) 2001 by Andreas Gruenbacher <a.gruenbacher@computer.org>
  Copyright (c) 2001-2002 Silicon Graphics, Inc.  All Rights Reserved.
  Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com>
*/
#ifndef _LINUX_XATTR_H
#define _LINUX_XATTR_H


#include <linux/slab.h>
#include <linux/types.h>
#include <linux/spinlock.h>
#include <uapi/linux/xattr.h>

struct inode;
struct dentry;

struct xattr_handler {
	const char *prefix;
	int flags;	/* fs private flags passed back to the handlers */
	size_t (*list)(struct dentry *dentry, char *list, size_t list_size,
		       const char *name, size_t name_len, int handler_flags);
	int (*get)(struct dentry *dentry, const char *name, void *buffer,
		   size_t size, int handler_flags);
	int (*set)(struct dentry *dentry, const char *name, const void *buffer,
		   size_t size, int flags, int handler_flags);
};

struct xattr {
	char *name;
	void *value;
	size_t value_len;
};

ssize_t xattr_getsecurity(struct inode *, const char *, void *, size_t);
ssize_t vfs_getxattr(struct dentry *, const char *, void *, size_t);
ssize_t vfs_listxattr(struct dentry *d, char *list, size_t size);
int __vfs_setxattr_noperm(struct dentry *, const char *, const void *, size_t, int);
int vfs_setxattr(struct dentry *, const char *, const void *, size_t, int);
int vfs_removexattr(struct dentry *, const char *);

ssize_t generic_getxattr(struct dentry *dentry, const char *name, void *buffer, size_t size);
ssize_t generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size);
int generic_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags);
int generic_removexattr(struct dentry *dentry, const char *name);
ssize_t vfs_getxattr_alloc(struct dentry *dentry, const char *name,
			   char **xattr_value, size_t size, gfp_t flags);
int vfs_xattr_cmp(struct dentry *dentry, const char *xattr_name,
		  const char *value, size_t size, gfp_t flags);

struct simple_xattrs {
	struct list_head head;
	spinlock_t lock;
};

struct simple_xattr {
	struct list_head list;
	char *name;
	size_t size;
	char value[0];
};

/*
 * initialize the simple_xattrs structure
 */
static inline void simple_xattrs_init(struct simple_xattrs *xattrs)
{
	INIT_LIST_HEAD(&xattrs->head);
	spin_lock_init(&xattrs->lock);
}

/*
 * free all the xattrs
 */
static inline void simple_xattrs_free(struct simple_xattrs *xattrs)
{
	struct simple_xattr *xattr, *node;

	list_for_each_entry_safe(xattr, node, &xattrs->head, list) {
		kfree(xattr->name);
		kfree(xattr);
	}
}

struct simple_xattr *simple_xattr_alloc(const void *value, size_t size);
int simple_xattr_get(struct simple_xattrs *xattrs, const char *name,
		     void *buffer, size_t size);
int simple_xattr_set(struct simple_xattrs *xattrs, const char *name,
		     const void *value, size_t size, int flags);
int simple_xattr_remove(struct simple_xattrs *xattrs, const char *name);
ssize_t simple_xattr_list(struct simple_xattrs *xattrs, char *buffer,
			  size_t size);
void simple_xattr_list_add(struct simple_xattrs *xattrs,
			   struct simple_xattr *new_xattr);

#endif	/* _LINUX_XATTR_H */
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