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ext4: Use bitops to read/modify i_flags in struct ext4_inode_info

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At several places we modify EXT4_I(inode)->i_flags without holding
i_mutex (ext4_do_update_inode, ...). These modifications are racy and
we can lose updates to i_flags. So convert handling of i_flags to use
bitops which are atomic.

https://bugzilla.kernel.org/show_bug.cgi?id=15792

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Dmitry Monakhov
2010-05-16 22:00:00 -04:00
committed by Theodore Ts'o
parent 24676da469
commit 12e9b89200
13 changed files with 136 additions and 56 deletions
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109
fs/ext4/ext4.h
View File

@@ -344,6 +344,83 @@ static inline __u32 ext4_mask_flags(umode_t mode, __u32 flags)
return flags & EXT4_OTHER_FLMASK;
}
/*
* Inode flags used for atomic set/get
*/
enum {
EXT4_INODE_SECRM = 0, /* Secure deletion */
EXT4_INODE_UNRM = 1, /* Undelete */
EXT4_INODE_COMPR = 2, /* Compress file */
EXT4_INODE_SYNC = 3, /* Synchronous updates */
EXT4_INODE_IMMUTABLE = 4, /* Immutable file */
EXT4_INODE_APPEND = 5, /* writes to file may only append */
EXT4_INODE_NODUMP = 6, /* do not dump file */
EXT4_INODE_NOATIME = 7, /* do not update atime */
/* Reserved for compression usage... */
EXT4_INODE_DIRTY = 8,
EXT4_INODE_COMPRBLK = 9, /* One or more compressed clusters */
EXT4_INODE_NOCOMPR = 10, /* Don't compress */
EXT4_INODE_ECOMPR = 11, /* Compression error */
/* End compression flags --- maybe not all used */
EXT4_INODE_INDEX = 12, /* hash-indexed directory */
EXT4_INODE_IMAGIC = 13, /* AFS directory */
EXT4_INODE_JOURNAL_DATA = 14, /* file data should be journaled */
EXT4_INODE_NOTAIL = 15, /* file tail should not be merged */
EXT4_INODE_DIRSYNC = 16, /* dirsync behaviour (directories only) */
EXT4_INODE_TOPDIR = 17, /* Top of directory hierarchies*/
EXT4_INODE_HUGE_FILE = 18, /* Set to each huge file */
EXT4_INODE_EXTENTS = 19, /* Inode uses extents */
EXT4_INODE_EA_INODE = 21, /* Inode used for large EA */
EXT4_INODE_EOFBLOCKS = 22, /* Blocks allocated beyond EOF */
EXT4_INODE_RESERVED = 31, /* reserved for ext4 lib */
};
#define TEST_FLAG_VALUE(FLAG) (EXT4_##FLAG##_FL == (1 << EXT4_INODE_##FLAG))
#define CHECK_FLAG_VALUE(FLAG) if (!TEST_FLAG_VALUE(FLAG)) { \
printk(KERN_EMERG "EXT4 flag fail: " #FLAG ": %d %d\n", \
EXT4_##FLAG##_FL, EXT4_INODE_##FLAG); BUG_ON(1); }
/*
* Since it's pretty easy to mix up bit numbers and hex values, and we
* can't do a compile-time test for ENUM values, we use a run-time
* test to make sure that EXT4_XXX_FL is consistent with respect to
* EXT4_INODE_XXX. If all is well the printk and BUG_ON will all drop
* out so it won't cost any extra space in the compiled kernel image.
* But it's important that these values are the same, since we are
* using EXT4_INODE_XXX to test for the flag values, but EXT4_XX_FL
* must be consistent with the values of FS_XXX_FL defined in
* include/linux/fs.h and the on-disk values found in ext2, ext3, and
* ext4 filesystems, and of course the values defined in e2fsprogs.
*
* It's not paranoia if the Murphy's Law really *is* out to get you. :-)
*/
static inline void ext4_check_flag_values(void)
{
CHECK_FLAG_VALUE(SECRM);
CHECK_FLAG_VALUE(UNRM);
CHECK_FLAG_VALUE(COMPR);
CHECK_FLAG_VALUE(SYNC);
CHECK_FLAG_VALUE(IMMUTABLE);
CHECK_FLAG_VALUE(APPEND);
CHECK_FLAG_VALUE(NODUMP);
CHECK_FLAG_VALUE(NOATIME);
CHECK_FLAG_VALUE(DIRTY);
CHECK_FLAG_VALUE(COMPRBLK);
CHECK_FLAG_VALUE(NOCOMPR);
CHECK_FLAG_VALUE(ECOMPR);
CHECK_FLAG_VALUE(INDEX);
CHECK_FLAG_VALUE(IMAGIC);
CHECK_FLAG_VALUE(JOURNAL_DATA);
CHECK_FLAG_VALUE(NOTAIL);
CHECK_FLAG_VALUE(DIRSYNC);
CHECK_FLAG_VALUE(TOPDIR);
CHECK_FLAG_VALUE(HUGE_FILE);
CHECK_FLAG_VALUE(EXTENTS);
CHECK_FLAG_VALUE(EA_INODE);
CHECK_FLAG_VALUE(EOFBLOCKS);
CHECK_FLAG_VALUE(RESERVED);
}
/* Used to pass group descriptor data when online resize is done */
struct ext4_new_group_input {
__u32 group; /* Group number for this data */
@@ -639,9 +716,8 @@ struct ext4_ext_cache {
*/
struct ext4_inode_info {
__le32 i_data[15]; /* unconverted */
__u32 i_flags;
ext4_fsblk_t i_file_acl;
__u32 i_dtime;
ext4_fsblk_t i_file_acl;
/*
* i_block_group is the number of the block group which contains
@@ -652,6 +728,7 @@ struct ext4_inode_info {
*/
ext4_group_t i_block_group;
unsigned long i_state_flags; /* Dynamic state flags */
unsigned long i_flags;
ext4_lblk_t i_dir_start_lookup;
#ifdef CONFIG_EXT4_FS_XATTR
@@ -1087,20 +1164,22 @@ enum {
EXT4_STATE_DIO_UNWRITTEN, /* need convert on dio done*/
};
static inline int ext4_test_inode_state(struct inode *inode, int bit)
{
return test_bit(bit, &EXT4_I(inode)->i_state_flags);
#define EXT4_INODE_BIT_FNS(name, field) \
static inline int ext4_test_inode_##name(struct inode *inode, int bit) \
{ \
return test_bit(bit, &EXT4_I(inode)->i_##field); \
} \
static inline void ext4_set_inode_##name(struct inode *inode, int bit) \
{ \
set_bit(bit, &EXT4_I(inode)->i_##field); \
} \
static inline void ext4_clear_inode_##name(struct inode *inode, int bit) \
{ \
clear_bit(bit, &EXT4_I(inode)->i_##field); \
}
static inline void ext4_set_inode_state(struct inode *inode, int bit)
{
set_bit(bit, &EXT4_I(inode)->i_state_flags);
}
static inline void ext4_clear_inode_state(struct inode *inode, int bit)
{
clear_bit(bit, &EXT4_I(inode)->i_state_flags);
}
EXT4_INODE_BIT_FNS(flag, flags)
EXT4_INODE_BIT_FNS(state, state_flags)
#else
/* Assume that user mode programs are passing in an ext4fs superblock, not
* a kernel struct super_block. This will allow us to call the feature-test
@@ -1287,7 +1366,7 @@ struct ext4_dir_entry_2 {
#define is_dx(dir) (EXT4_HAS_COMPAT_FEATURE(dir->i_sb, \
EXT4_FEATURE_COMPAT_DIR_INDEX) && \
(EXT4_I(dir)->i_flags & EXT4_INDEX_FL))
ext4_test_inode_flag((dir), EXT4_INODE_INDEX))
#define EXT4_DIR_LINK_MAX(dir) (!is_dx(dir) && (dir)->i_nlink >= EXT4_LINK_MAX)
#define EXT4_DIR_LINK_EMPTY(dir) ((dir)->i_nlink == 2 || (dir)->i_nlink == 1)