kernel-ark/include/linux/reiserfs_fs_i.h
Vladimir Saveliev de14569f94 [PATCH] resierfs: avoid tail packing if an inode was ever mmapped
This patch fixes a confusion reiserfs has for a long time.

On release file operation reiserfs used to try to pack file data stored in
last incomplete page of some files into metadata blocks.  After packing the
page got cleared with clear_page_dirty.  It did not take into account that
the page may be mmaped into other process's address space.  Recent
replacement for clear_page_dirty cancel_dirty_page found the confusion with
sanity check that page has to be not mapped.

The patch fixes the confusion by making reiserfs avoid tail packing if an
inode was ever mmapped.  reiserfs_mmap and reiserfs_file_release are
serialized with mutex in reiserfs specific inode.  reiserfs_mmap locks the
mutex and sets a bit in reiserfs specific inode flags.
reiserfs_file_release checks the bit having the mutex locked.  If bit is
set - tail packing is avoided.  This eliminates a possibility that mmapped
page gets cancel_page_dirty-ed.

Signed-off-by: Vladimir Saveliev <vs@namesys.com>
Cc: Jeff Mahoney <jeffm@suse.com>
Cc: Chris Mason <mason@suse.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-01-23 07:52:06 -08:00

68 lines
2.2 KiB
C

#ifndef _REISER_FS_I
#define _REISER_FS_I
#include <linux/list.h>
struct reiserfs_journal_list;
/** bitmasks for i_flags field in reiserfs-specific part of inode */
typedef enum {
/** this says what format of key do all items (but stat data) of
an object have. If this is set, that format is 3.6 otherwise
- 3.5 */
i_item_key_version_mask = 0x0001,
/** If this is unset, object has 3.5 stat data, otherwise, it has
3.6 stat data with 64bit size, 32bit nlink etc. */
i_stat_data_version_mask = 0x0002,
/** file might need tail packing on close */
i_pack_on_close_mask = 0x0004,
/** don't pack tail of file */
i_nopack_mask = 0x0008,
/** If those is set, "safe link" was created for this file during
truncate or unlink. Safe link is used to avoid leakage of disk
space on crash with some files open, but unlinked. */
i_link_saved_unlink_mask = 0x0010,
i_link_saved_truncate_mask = 0x0020,
i_has_xattr_dir = 0x0040,
i_data_log = 0x0080,
i_ever_mapped = 0x0100
} reiserfs_inode_flags;
struct reiserfs_inode_info {
__u32 i_key[4]; /* key is still 4 32 bit integers */
/** transient inode flags that are never stored on disk. Bitmasks
for this field are defined above. */
__u32 i_flags;
__u32 i_first_direct_byte; // offset of first byte stored in direct item.
/* copy of persistent inode flags read from sd_attrs. */
__u32 i_attrs;
int i_prealloc_block; /* first unused block of a sequence of unused blocks */
int i_prealloc_count; /* length of that sequence */
struct list_head i_prealloc_list; /* per-transaction list of inodes which
* have preallocated blocks */
unsigned new_packing_locality:1; /* new_packig_locality is created; new blocks
* for the contents of this directory should be
* displaced */
/* we use these for fsync or O_SYNC to decide which transaction
** needs to be committed in order for this inode to be properly
** flushed */
unsigned long i_trans_id;
struct reiserfs_journal_list *i_jl;
struct mutex i_mmap;
#ifdef CONFIG_REISERFS_FS_POSIX_ACL
struct posix_acl *i_acl_access;
struct posix_acl *i_acl_default;
#endif
#ifdef CONFIG_REISERFS_FS_XATTR
struct rw_semaphore xattr_sem;
#endif
struct inode vfs_inode;
};
#endif