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authorLinus Torvalds <torvalds@linux-foundation.org>2012-08-01 10:26:23 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-08-01 10:26:23 -0700
commita0e881b7c189fa2bd76c024dbff91e79511c971d (patch)
tree0c801918565b08921d21aceee5b326f64d998f5f /fs/ext4
parenteff0d13f3823f35d70228cd151d2a2c89288ff32 (diff)
parentdbc6e0222d79e78925fe20733844a796a4b72cf9 (diff)
downloadlinux-a0e881b7c189fa2bd76c024dbff91e79511c971d.tar.bz2
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull second vfs pile from Al Viro: "The stuff in there: fsfreeze deadlock fixes by Jan (essentially, the deadlock reproduced by xfstests 068), symlink and hardlink restriction patches, plus assorted cleanups and fixes. Note that another fsfreeze deadlock (emergency thaw one) is *not* dealt with - the series by Fernando conflicts a lot with Jan's, breaks userland ABI (FIFREEZE semantics gets changed) and trades the deadlock for massive vfsmount leak; this is going to be handled next cycle. There probably will be another pull request, but that stuff won't be in it." Fix up trivial conflicts due to unrelated changes next to each other in drivers/{staging/gdm72xx/usb_boot.c, usb/gadget/storage_common.c} * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (54 commits) delousing target_core_file a bit Documentation: Correct s_umount state for freeze_fs/unfreeze_fs fs: Remove old freezing mechanism ext2: Implement freezing btrfs: Convert to new freezing mechanism nilfs2: Convert to new freezing mechanism ntfs: Convert to new freezing mechanism fuse: Convert to new freezing mechanism gfs2: Convert to new freezing mechanism ocfs2: Convert to new freezing mechanism xfs: Convert to new freezing code ext4: Convert to new freezing mechanism fs: Protect write paths by sb_start_write - sb_end_write fs: Skip atime update on frozen filesystem fs: Add freezing handling to mnt_want_write() / mnt_drop_write() fs: Improve filesystem freezing handling switch the protection of percpu_counter list to spinlock nfsd: Push mnt_want_write() outside of i_mutex btrfs: Push mnt_want_write() outside of i_mutex fat: Push mnt_want_write() outside of i_mutex ...
Diffstat (limited to 'fs/ext4')
-rw-r--r--fs/ext4/inode.c15
-rw-r--r--fs/ext4/mmp.c6
-rw-r--r--fs/ext4/super.c31
3 files changed, 23 insertions, 29 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 89b59cb7f9b8..6324f74e0342 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -233,6 +233,11 @@ void ext4_evict_inode(struct inode *inode)
if (is_bad_inode(inode))
goto no_delete;
+ /*
+ * Protect us against freezing - iput() caller didn't have to have any
+ * protection against it
+ */
+ sb_start_intwrite(inode->i_sb);
handle = ext4_journal_start(inode, ext4_blocks_for_truncate(inode)+3);
if (IS_ERR(handle)) {
ext4_std_error(inode->i_sb, PTR_ERR(handle));
@@ -242,6 +247,7 @@ void ext4_evict_inode(struct inode *inode)
* cleaned up.
*/
ext4_orphan_del(NULL, inode);
+ sb_end_intwrite(inode->i_sb);
goto no_delete;
}
@@ -273,6 +279,7 @@ void ext4_evict_inode(struct inode *inode)
stop_handle:
ext4_journal_stop(handle);
ext4_orphan_del(NULL, inode);
+ sb_end_intwrite(inode->i_sb);
goto no_delete;
}
}
@@ -301,6 +308,7 @@ void ext4_evict_inode(struct inode *inode)
else
ext4_free_inode(handle, inode);
ext4_journal_stop(handle);
+ sb_end_intwrite(inode->i_sb);
return;
no_delete:
ext4_clear_inode(inode); /* We must guarantee clearing of inode... */
@@ -4779,11 +4787,7 @@ int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
get_block_t *get_block;
int retries = 0;
- /*
- * This check is racy but catches the common case. We rely on
- * __block_page_mkwrite() to do a reliable check.
- */
- vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
+ sb_start_pagefault(inode->i_sb);
/* Delalloc case is easy... */
if (test_opt(inode->i_sb, DELALLOC) &&
!ext4_should_journal_data(inode) &&
@@ -4851,5 +4855,6 @@ retry_alloc:
out_ret:
ret = block_page_mkwrite_return(ret);
out:
+ sb_end_pagefault(inode->i_sb);
return ret;
}
diff --git a/fs/ext4/mmp.c b/fs/ext4/mmp.c
index f99a1311e847..fe7c63f4717e 100644
--- a/fs/ext4/mmp.c
+++ b/fs/ext4/mmp.c
@@ -44,6 +44,11 @@ static int write_mmp_block(struct super_block *sb, struct buffer_head *bh)
{
struct mmp_struct *mmp = (struct mmp_struct *)(bh->b_data);
+ /*
+ * We protect against freezing so that we don't create dirty buffers
+ * on frozen filesystem.
+ */
+ sb_start_write(sb);
ext4_mmp_csum_set(sb, mmp);
mark_buffer_dirty(bh);
lock_buffer(bh);
@@ -51,6 +56,7 @@ static int write_mmp_block(struct super_block *sb, struct buffer_head *bh)
get_bh(bh);
submit_bh(WRITE_SYNC, bh);
wait_on_buffer(bh);
+ sb_end_write(sb);
if (unlikely(!buffer_uptodate(bh)))
return 1;
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 2d51cd9af225..d76ec8277d3f 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -331,33 +331,17 @@ static void ext4_put_nojournal(handle_t *handle)
* journal_end calls result in the superblock being marked dirty, so
* that sync() will call the filesystem's write_super callback if
* appropriate.
- *
- * To avoid j_barrier hold in userspace when a user calls freeze(),
- * ext4 prevents a new handle from being started by s_frozen, which
- * is in an upper layer.
*/
handle_t *ext4_journal_start_sb(struct super_block *sb, int nblocks)
{
journal_t *journal;
- handle_t *handle;
trace_ext4_journal_start(sb, nblocks, _RET_IP_);
if (sb->s_flags & MS_RDONLY)
return ERR_PTR(-EROFS);
+ WARN_ON(sb->s_writers.frozen == SB_FREEZE_COMPLETE);
journal = EXT4_SB(sb)->s_journal;
- handle = ext4_journal_current_handle();
-
- /*
- * If a handle has been started, it should be allowed to
- * finish, otherwise deadlock could happen between freeze
- * and others(e.g. truncate) due to the restart of the
- * journal handle if the filesystem is forzen and active
- * handles are not stopped.
- */
- if (!handle)
- vfs_check_frozen(sb, SB_FREEZE_TRANS);
-
if (!journal)
return ext4_get_nojournal();
/*
@@ -2747,6 +2731,7 @@ static int ext4_run_li_request(struct ext4_li_request *elr)
sb = elr->lr_super;
ngroups = EXT4_SB(sb)->s_groups_count;
+ sb_start_write(sb);
for (group = elr->lr_next_group; group < ngroups; group++) {
gdp = ext4_get_group_desc(sb, group, NULL);
if (!gdp) {
@@ -2773,6 +2758,7 @@ static int ext4_run_li_request(struct ext4_li_request *elr)
elr->lr_next_sched = jiffies + elr->lr_timeout;
elr->lr_next_group = group + 1;
}
+ sb_end_write(sb);
return ret;
}
@@ -4460,10 +4446,8 @@ int ext4_force_commit(struct super_block *sb)
return 0;
journal = EXT4_SB(sb)->s_journal;
- if (journal) {
- vfs_check_frozen(sb, SB_FREEZE_TRANS);
+ if (journal)
ret = ext4_journal_force_commit(journal);
- }
return ret;
}
@@ -4493,9 +4477,8 @@ static int ext4_sync_fs(struct super_block *sb, int wait)
* gives us a chance to flush the journal completely and mark the fs clean.
*
* Note that only this function cannot bring a filesystem to be in a clean
- * state independently, because ext4 prevents a new handle from being started
- * by @sb->s_frozen, which stays in an upper layer. It thus needs help from
- * the upper layer.
+ * state independently. It relies on upper layer to stop all data & metadata
+ * modifications.
*/
static int ext4_freeze(struct super_block *sb)
{
@@ -4522,7 +4505,7 @@ static int ext4_freeze(struct super_block *sb)
EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
error = ext4_commit_super(sb, 1);
out:
- /* we rely on s_frozen to stop further updates */
+ /* we rely on upper layer to stop further updates */
jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
return error;
}