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ext3: Use bitops to read/modify EXT3_I(inode)->i_state
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At several places we modify EXT3_I(inode)->i_state without holding i_mutex
(ext3_release_file, ext3_bmap, ext3_journalled_writepage, ext3_do_update_inode,
...). These modifications are racy and we can lose updates to i_state. So
convert handling of i_state to use bitops which are atomic.

Signed-off-by: Jan Kara <[email protected]>
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@jankara
jankara committed Mar 4, 2010
1 parent 26245c9 commit 9df9393
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Showing 5 changed files with 44 additions and 27 deletions.
4 changes: 2 additions & 2 deletions fs/ext3/file.c
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Original file line number Diff line number Diff line change
Expand Up @@ -33,9 +33,9 @@
*/
static int ext3_release_file (struct inode * inode, struct file * filp)
{
if (EXT3_I(inode)->i_state & EXT3_STATE_FLUSH_ON_CLOSE) {
if (ext3_test_inode_state(inode, EXT3_STATE_FLUSH_ON_CLOSE)) {
filemap_flush(inode->i_mapping);
EXT3_I(inode)->i_state &= ~EXT3_STATE_FLUSH_ON_CLOSE;
ext3_clear_inode_state(inode, EXT3_STATE_FLUSH_ON_CLOSE);
}
/* if we are the last writer on the inode, drop the block reservation */
if ((filp->f_mode & FMODE_WRITE) &&
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18 changes: 9 additions & 9 deletions fs/ext3/inode.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1378,7 +1378,7 @@ static int ext3_journalled_write_end(struct file *file,
*/
if (pos + len > inode->i_size && ext3_can_truncate(inode))
ext3_orphan_add(handle, inode);
EXT3_I(inode)->i_state |= EXT3_STATE_JDATA;
ext3_set_inode_state(inode, EXT3_STATE_JDATA);
if (inode->i_size > EXT3_I(inode)->i_disksize) {
EXT3_I(inode)->i_disksize = inode->i_size;
ret2 = ext3_mark_inode_dirty(handle, inode);
Expand Down Expand Up @@ -1417,7 +1417,7 @@ static sector_t ext3_bmap(struct address_space *mapping, sector_t block)
journal_t *journal;
int err;

if (EXT3_I(inode)->i_state & EXT3_STATE_JDATA) {
if (ext3_test_inode_state(inode, EXT3_STATE_JDATA)) {
/*
* This is a REALLY heavyweight approach, but the use of
* bmap on dirty files is expected to be extremely rare:
Expand All @@ -1436,7 +1436,7 @@ static sector_t ext3_bmap(struct address_space *mapping, sector_t block)
* everything they get.
*/

EXT3_I(inode)->i_state &= ~EXT3_STATE_JDATA;
ext3_clear_inode_state(inode, EXT3_STATE_JDATA);
journal = EXT3_JOURNAL(inode);
journal_lock_updates(journal);
err = journal_flush(journal);
Expand Down Expand Up @@ -1670,7 +1670,7 @@ static int ext3_journalled_writepage(struct page *page,
PAGE_CACHE_SIZE, NULL, write_end_fn);
if (ret == 0)
ret = err;
EXT3_I(inode)->i_state |= EXT3_STATE_JDATA;
ext3_set_inode_state(inode, EXT3_STATE_JDATA);
unlock_page(page);
} else {
/*
Expand Down Expand Up @@ -2402,7 +2402,7 @@ void ext3_truncate(struct inode *inode)
goto out_notrans;

if (inode->i_size == 0 && ext3_should_writeback_data(inode))
ei->i_state |= EXT3_STATE_FLUSH_ON_CLOSE;
ext3_set_inode_state(inode, EXT3_STATE_FLUSH_ON_CLOSE);

/*
* We have to lock the EOF page here, because lock_page() nests
Expand Down Expand Up @@ -2721,7 +2721,7 @@ int ext3_get_inode_loc(struct inode *inode, struct ext3_iloc *iloc)
{
/* We have all inode data except xattrs in memory here. */
return __ext3_get_inode_loc(inode, iloc,
!(EXT3_I(inode)->i_state & EXT3_STATE_XATTR));
!ext3_test_inode_state(inode, EXT3_STATE_XATTR));
}

void ext3_set_inode_flags(struct inode *inode)
Expand Down Expand Up @@ -2893,7 +2893,7 @@ struct inode *ext3_iget(struct super_block *sb, unsigned long ino)
EXT3_GOOD_OLD_INODE_SIZE +
ei->i_extra_isize;
if (*magic == cpu_to_le32(EXT3_XATTR_MAGIC))
ei->i_state |= EXT3_STATE_XATTR;
ext3_set_inode_state(inode, EXT3_STATE_XATTR);
}
} else
ei->i_extra_isize = 0;
Expand Down Expand Up @@ -2955,7 +2955,7 @@ static int ext3_do_update_inode(handle_t *handle,

/* For fields not not tracking in the in-memory inode,
* initialise them to zero for new inodes. */
if (ei->i_state & EXT3_STATE_NEW)
if (ext3_test_inode_state(inode, EXT3_STATE_NEW))
memset(raw_inode, 0, EXT3_SB(inode->i_sb)->s_inode_size);

ext3_get_inode_flags(ei);
Expand Down Expand Up @@ -3052,7 +3052,7 @@ static int ext3_do_update_inode(handle_t *handle,
rc = ext3_journal_dirty_metadata(handle, bh);
if (!err)
err = rc;
ei->i_state &= ~EXT3_STATE_NEW;
ext3_clear_inode_state(inode, EXT3_STATE_NEW);

atomic_set(&ei->i_sync_tid, handle->h_transaction->t_tid);
out_brelse:
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14 changes: 7 additions & 7 deletions fs/ext3/xattr.c
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Original file line number Diff line number Diff line change
Expand Up @@ -274,7 +274,7 @@ ext3_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
void *end;
int error;

if (!(EXT3_I(inode)->i_state & EXT3_STATE_XATTR))
if (!ext3_test_inode_state(inode, EXT3_STATE_XATTR))
return -ENODATA;
error = ext3_get_inode_loc(inode, &iloc);
if (error)
Expand Down Expand Up @@ -403,7 +403,7 @@ ext3_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
void *end;
int error;

if (!(EXT3_I(inode)->i_state & EXT3_STATE_XATTR))
if (!ext3_test_inode_state(inode, EXT3_STATE_XATTR))
return 0;
error = ext3_get_inode_loc(inode, &iloc);
if (error)
Expand Down Expand Up @@ -882,7 +882,7 @@ ext3_xattr_ibody_find(struct inode *inode, struct ext3_xattr_info *i,
is->s.base = is->s.first = IFIRST(header);
is->s.here = is->s.first;
is->s.end = (void *)raw_inode + EXT3_SB(inode->i_sb)->s_inode_size;
if (EXT3_I(inode)->i_state & EXT3_STATE_XATTR) {
if (ext3_test_inode_state(inode, EXT3_STATE_XATTR)) {
error = ext3_xattr_check_names(IFIRST(header), is->s.end);
if (error)
return error;
Expand Down Expand Up @@ -914,10 +914,10 @@ ext3_xattr_ibody_set(handle_t *handle, struct inode *inode,
header = IHDR(inode, ext3_raw_inode(&is->iloc));
if (!IS_LAST_ENTRY(s->first)) {
header->h_magic = cpu_to_le32(EXT3_XATTR_MAGIC);
EXT3_I(inode)->i_state |= EXT3_STATE_XATTR;
ext3_set_inode_state(inode, EXT3_STATE_XATTR);
} else {
header->h_magic = cpu_to_le32(0);
EXT3_I(inode)->i_state &= ~EXT3_STATE_XATTR;
ext3_clear_inode_state(inode, EXT3_STATE_XATTR);
}
return 0;
}
Expand Down Expand Up @@ -967,10 +967,10 @@ ext3_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
if (error)
goto cleanup;

if (EXT3_I(inode)->i_state & EXT3_STATE_NEW) {
if (ext3_test_inode_state(inode, EXT3_STATE_NEW)) {
struct ext3_inode *raw_inode = ext3_raw_inode(&is.iloc);
memset(raw_inode, 0, EXT3_SB(inode->i_sb)->s_inode_size);
EXT3_I(inode)->i_state &= ~EXT3_STATE_NEW;
ext3_clear_inode_state(inode, EXT3_STATE_NEW);
}

error = ext3_xattr_ibody_find(inode, &i, &is);
Expand Down
33 changes: 25 additions & 8 deletions include/linux/ext3_fs.h
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Original file line number Diff line number Diff line change
Expand Up @@ -202,14 +202,6 @@ static inline __u32 ext3_mask_flags(umode_t mode, __u32 flags)
return flags & EXT3_OTHER_FLMASK;
}

/*
* Inode dynamic state flags
*/
#define EXT3_STATE_JDATA 0x00000001 /* journaled data exists */
#define EXT3_STATE_NEW 0x00000002 /* inode is newly created */
#define EXT3_STATE_XATTR 0x00000004 /* has in-inode xattrs */
#define EXT3_STATE_FLUSH_ON_CLOSE 0x00000008

/* Used to pass group descriptor data when online resize is done */
struct ext3_new_group_input {
__u32 group; /* Group number for this data */
Expand Down Expand Up @@ -560,6 +552,31 @@ static inline int ext3_valid_inum(struct super_block *sb, unsigned long ino)
(ino >= EXT3_FIRST_INO(sb) &&
ino <= le32_to_cpu(EXT3_SB(sb)->s_es->s_inodes_count));
}

/*
* Inode dynamic state flags
*/
enum {
EXT3_STATE_JDATA, /* journaled data exists */
EXT3_STATE_NEW, /* inode is newly created */
EXT3_STATE_XATTR, /* has in-inode xattrs */
EXT3_STATE_FLUSH_ON_CLOSE, /* flush dirty pages on close */
};

static inline int ext3_test_inode_state(struct inode *inode, int bit)
{
return test_bit(bit, &EXT3_I(inode)->i_state);
}

static inline void ext3_set_inode_state(struct inode *inode, int bit)
{
set_bit(bit, &EXT3_I(inode)->i_state);
}

static inline void ext3_clear_inode_state(struct inode *inode, int bit)
{
clear_bit(bit, &EXT3_I(inode)->i_state);
}
#else
/* Assume that user mode programs are passing in an ext3fs superblock, not
* a kernel struct super_block. This will allow us to call the feature-test
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2 changes: 1 addition & 1 deletion include/linux/ext3_fs_i.h
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Original file line number Diff line number Diff line change
Expand Up @@ -87,7 +87,7 @@ struct ext3_inode_info {
* near to their parent directory's inode.
*/
__u32 i_block_group;
__u32 i_state; /* Dynamic state flags for ext3 */
unsigned long i_state; /* Dynamic state flags for ext3 */

/* block reservation info */
struct ext3_block_alloc_info *i_block_alloc_info;
Expand Down

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