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Message-ID: <20071106171820.GE23689@duck.suse.cz>
Date: Tue, 6 Nov 2007 18:18:20 +0100
From: Jan Kara <jack@...e.cz>
To: linux-kernel@...r.kernel.org
Cc: linux-ext4@...r.kernel.org
Subject: [RFC] [PATCH 1/3] Recursive mtime for ext3
Hello,
the following patch makes more lightweight handling of
EXT3_I(inode)->i_flags possible.
Honza
--
Jan Kara <jack@...e.cz>
SUSE Labs, CR
---
Implement atomic updates of EXT3_I(inode)->i_flags. So far the i_flags access
was guarded mostly by i_mutex but this is quite heavy-weight. We now use
inode->i_lock to protect i_flags reading and updates in ext3. This patch
introduces a bogus warning that jflag and oldflags may be uninitialized -
anyone knows how to cleanly get rid of it?
Signed-off-by: Jan Kara <jack@...e.cz>
diff -rupX /home/jack/.kerndiffexclude linux-2.6.23/fs/ext3/dir.c linux-2.6.23-1-i_flags_atomicity/fs/ext3/dir.c
--- linux-2.6.23/fs/ext3/dir.c 2007-10-11 12:01:23.000000000 +0200
+++ linux-2.6.23-1-i_flags_atomicity/fs/ext3/dir.c 2007-11-05 14:04:56.000000000 +0100
@@ -108,10 +108,10 @@ static int ext3_readdir(struct file * fi
sb = inode->i_sb;
#ifdef CONFIG_EXT3_INDEX
- if (EXT3_HAS_COMPAT_FEATURE(inode->i_sb,
- EXT3_FEATURE_COMPAT_DIR_INDEX) &&
- ((EXT3_I(inode)->i_flags & EXT3_INDEX_FL) ||
- ((inode->i_size >> sb->s_blocksize_bits) == 1))) {
+ if (is_dx(inode) ||
+ (EXT3_HAS_COMPAT_FEATURE(inode->i_sb, \
+ EXT3_FEATURE_COMPAT_DIR_INDEX) &&
+ (inode->i_size >> sb->s_blocksize_bits) == 1)) {
err = ext3_dx_readdir(filp, dirent, filldir);
if (err != ERR_BAD_DX_DIR) {
ret = err;
@@ -121,7 +121,9 @@ static int ext3_readdir(struct file * fi
* We don't set the inode dirty flag since it's not
* critical that it get flushed back to the disk.
*/
+ spin_lock(&inode->i_lock);
EXT3_I(filp->f_path.dentry->d_inode)->i_flags &= ~EXT3_INDEX_FL;
+ spin_unlock(&inode->i_lock);
}
#endif
stored = 0;
diff -rupX /home/jack/.kerndiffexclude linux-2.6.23/fs/ext3/ialloc.c linux-2.6.23-1-i_flags_atomicity/fs/ext3/ialloc.c
--- linux-2.6.23/fs/ext3/ialloc.c 2006-11-29 22:57:37.000000000 +0100
+++ linux-2.6.23-1-i_flags_atomicity/fs/ext3/ialloc.c 2007-11-05 14:14:50.000000000 +0100
@@ -278,7 +278,7 @@ static int find_group_orlov(struct super
ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);
if ((parent == sb->s_root->d_inode) ||
- (EXT3_I(parent)->i_flags & EXT3_TOPDIR_FL)) {
+ ext3_test_inode_flags(parent, EXT3_TOPDIR_FL)) {
int best_ndir = inodes_per_group;
int best_group = -1;
@@ -566,7 +566,11 @@ got:
ei->i_dir_start_lookup = 0;
ei->i_disksize = 0;
+ /* Guard reading of directory's i_flags, created inode is safe as
+ * noone has a reference to it yet */
+ spin_lock(&dir->i_lock);
ei->i_flags = EXT3_I(dir)->i_flags & ~EXT3_INDEX_FL;
+ spin_unlock(&dir->i_lock);
if (S_ISLNK(mode))
ei->i_flags &= ~(EXT3_IMMUTABLE_FL|EXT3_APPEND_FL);
/* dirsync only applies to directories */
diff -rupX /home/jack/.kerndiffexclude linux-2.6.23/fs/ext3/inode.c linux-2.6.23-1-i_flags_atomicity/fs/ext3/inode.c
--- linux-2.6.23/fs/ext3/inode.c 2007-10-11 12:01:23.000000000 +0200
+++ linux-2.6.23-1-i_flags_atomicity/fs/ext3/inode.c 2007-11-05 14:24:39.000000000 +0100
@@ -2557,8 +2557,10 @@ int ext3_get_inode_loc(struct inode *ino
void ext3_set_inode_flags(struct inode *inode)
{
- unsigned int flags = EXT3_I(inode)->i_flags;
+ unsigned int flags;
+ spin_lock(&inode->i_lock);
+ flags = EXT3_I(inode)->i_flags;
inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
if (flags & EXT3_SYNC_FL)
inode->i_flags |= S_SYNC;
@@ -2570,13 +2572,16 @@ void ext3_set_inode_flags(struct inode *
inode->i_flags |= S_NOATIME;
if (flags & EXT3_DIRSYNC_FL)
inode->i_flags |= S_DIRSYNC;
+ spin_unlock(&inode->i_lock);
}
/* Propagate flags from i_flags to EXT3_I(inode)->i_flags */
void ext3_get_inode_flags(struct ext3_inode_info *ei)
{
- unsigned int flags = ei->vfs_inode.i_flags;
+ unsigned int flags;
+ spin_lock(&ei->vfs_inode.i_lock);
+ flags = ei->vfs_inode.i_flags;
ei->i_flags &= ~(EXT3_SYNC_FL|EXT3_APPEND_FL|
EXT3_IMMUTABLE_FL|EXT3_NOATIME_FL|EXT3_DIRSYNC_FL);
if (flags & S_SYNC)
@@ -2589,6 +2594,7 @@ void ext3_get_inode_flags(struct ext3_in
ei->i_flags |= EXT3_NOATIME_FL;
if (flags & S_DIRSYNC)
ei->i_flags |= EXT3_DIRSYNC_FL;
+ spin_unlock(&ei->vfs_inode.i_lock);
}
void ext3_read_inode(struct inode * inode)
@@ -2781,7 +2787,9 @@ static int ext3_do_update_inode(handle_t
raw_inode->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec);
raw_inode->i_blocks = cpu_to_le32(inode->i_blocks);
raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
+ spin_lock(&inode->i_lock);
raw_inode->i_flags = cpu_to_le32(ei->i_flags);
+ spin_unlock(&inode->i_lock);
#ifdef EXT3_FRAGMENTS
raw_inode->i_faddr = cpu_to_le32(ei->i_faddr);
raw_inode->i_frag = ei->i_frag_no;
@@ -3209,10 +3217,12 @@ int ext3_change_inode_journal_flag(struc
* the inode's in-core data-journaling state flag now.
*/
+ spin_lock(&inode->i_lock);
if (val)
EXT3_I(inode)->i_flags |= EXT3_JOURNAL_DATA_FL;
else
EXT3_I(inode)->i_flags &= ~EXT3_JOURNAL_DATA_FL;
+ spin_unlock(&inode->i_lock);
ext3_set_aops(inode);
journal_unlock_updates(journal);
diff -rupX /home/jack/.kerndiffexclude linux-2.6.23/fs/ext3/ioctl.c linux-2.6.23-1-i_flags_atomicity/fs/ext3/ioctl.c
--- linux-2.6.23/fs/ext3/ioctl.c 2007-10-11 12:01:23.000000000 +0200
+++ linux-2.6.23-1-i_flags_atomicity/fs/ext3/ioctl.c 2007-11-05 14:32:12.000000000 +0100
@@ -29,7 +29,9 @@ int ext3_ioctl (struct inode * inode, st
switch (cmd) {
case EXT3_IOC_GETFLAGS:
ext3_get_inode_flags(ei);
+ spin_lock(&inode->i_lock);
flags = ei->i_flags & EXT3_FL_USER_VISIBLE;
+ spin_unlock(&inode->i_lock);
return put_user(flags, (int __user *) arg);
case EXT3_IOC_SETFLAGS: {
handle_t *handle = NULL;
@@ -51,10 +53,19 @@ int ext3_ioctl (struct inode * inode, st
flags &= ~EXT3_DIRSYNC_FL;
mutex_lock(&inode->i_mutex);
- oldflags = ei->i_flags;
+ handle = ext3_journal_start(inode, 1);
+ if (IS_ERR(handle)) {
+ mutex_unlock(&inode->i_mutex);
+ return PTR_ERR(handle);
+ }
+ if (IS_SYNC(inode))
+ handle->h_sync = 1;
+ err = ext3_reserve_inode_write(handle, inode, &iloc);
+ if (err)
+ goto flags_err;
- /* The JOURNAL_DATA flag is modifiable only by root */
- jflag = flags & EXT3_JOURNAL_DATA_FL;
+ spin_lock(&inode->i_lock);
+ oldflags = ei->i_flags;
/*
* The IMMUTABLE and APPEND_ONLY flags can only be changed by
@@ -64,8 +75,9 @@ int ext3_ioctl (struct inode * inode, st
*/
if ((flags ^ oldflags) & (EXT3_APPEND_FL | EXT3_IMMUTABLE_FL)) {
if (!capable(CAP_LINUX_IMMUTABLE)) {
- mutex_unlock(&inode->i_mutex);
- return -EPERM;
+ spin_unlock(&inode->i_lock);
+ err = -EPERM;
+ goto flags_err;
}
}
@@ -73,28 +85,19 @@ int ext3_ioctl (struct inode * inode, st
* The JOURNAL_DATA flag can only be changed by
* the relevant capability.
*/
+ jflag = flags & EXT3_JOURNAL_DATA_FL;
if ((jflag ^ oldflags) & (EXT3_JOURNAL_DATA_FL)) {
if (!capable(CAP_SYS_RESOURCE)) {
- mutex_unlock(&inode->i_mutex);
- return -EPERM;
+ spin_unlock(&inode->i_lock);
+ err = -EPERM;
+ goto flags_err;
}
}
-
- handle = ext3_journal_start(inode, 1);
- if (IS_ERR(handle)) {
- mutex_unlock(&inode->i_mutex);
- return PTR_ERR(handle);
- }
- if (IS_SYNC(inode))
- handle->h_sync = 1;
- err = ext3_reserve_inode_write(handle, inode, &iloc);
- if (err)
- goto flags_err;
-
flags = flags & EXT3_FL_USER_MODIFIABLE;
flags |= oldflags & ~EXT3_FL_USER_MODIFIABLE;
ei->i_flags = flags;
+ spin_unlock(&inode->i_lock);
ext3_set_inode_flags(inode);
inode->i_ctime = CURRENT_TIME_SEC;
diff -rupX /home/jack/.kerndiffexclude linux-2.6.23/include/linux/ext3_fs.h linux-2.6.23-1-i_flags_atomicity/include/linux/ext3_fs.h
--- linux-2.6.23/include/linux/ext3_fs.h 2007-07-16 17:47:28.000000000 +0200
+++ linux-2.6.23-1-i_flags_atomicity/include/linux/ext3_fs.h 2007-11-05 14:31:44.000000000 +0100
@@ -514,6 +514,17 @@ static inline int ext3_valid_inum(struct
(ino >= EXT3_FIRST_INO(sb) &&
ino <= le32_to_cpu(EXT3_SB(sb)->s_es->s_inodes_count));
}
+
+static inline unsigned int ext3_test_inode_flags(struct inode *inode, u32 flags)
+{
+ unsigned int ret;
+
+ spin_lock(&inode->i_lock);
+ ret = EXT3_I(inode)->i_flags & flags;
+ spin_unlock(&inode->i_lock);
+ return ret;
+}
+
#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
@@ -666,9 +677,18 @@ struct ext3_dir_entry_2 {
*/
#ifdef CONFIG_EXT3_INDEX
- #define is_dx(dir) (EXT3_HAS_COMPAT_FEATURE(dir->i_sb, \
- EXT3_FEATURE_COMPAT_DIR_INDEX) && \
- (EXT3_I(dir)->i_flags & EXT3_INDEX_FL))
+static inline int is_dx(struct inode *dir)
+{
+ int ret = 0;
+
+ if (EXT3_HAS_COMPAT_FEATURE(dir->i_sb, \
+ EXT3_FEATURE_COMPAT_DIR_INDEX)) {
+ spin_lock(&dir->i_lock);
+ ret = EXT3_I(dir)->i_flags & EXT3_INDEX_FL;
+ spin_unlock(&dir->i_lock);
+ }
+ return ret;
+}
#define EXT3_DIR_LINK_MAX(dir) (!is_dx(dir) && (dir)->i_nlink >= EXT3_LINK_MAX)
#define EXT3_DIR_LINK_EMPTY(dir) ((dir)->i_nlink == 2 || (dir)->i_nlink == 1)
#else
diff -rupX /home/jack/.kerndiffexclude linux-2.6.23/include/linux/ext3_fs_i.h linux-2.6.23-1-i_flags_atomicity/include/linux/ext3_fs_i.h
--- linux-2.6.23/include/linux/ext3_fs_i.h 2007-07-16 17:47:28.000000000 +0200
+++ linux-2.6.23-1-i_flags_atomicity/include/linux/ext3_fs_i.h 2007-11-05 14:26:43.000000000 +0100
@@ -69,7 +69,7 @@ struct ext3_block_alloc_info {
*/
struct ext3_inode_info {
__le32 i_data[15]; /* unconverted */
- __u32 i_flags;
+ __u32 i_flags; /* Guarded by inode->i_lock */
#ifdef EXT3_FRAGMENTS
__u32 i_faddr;
__u8 i_frag_no;
-
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