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authorJaegeuk Kim <jaegeuk.kim@samsung.com>2013-01-31 15:36:04 +0900
committerJaegeuk Kim <jaegeuk.kim@samsung.com>2013-02-12 07:15:01 +0900
commitd4686d56ec912d55fd8a9d6d509de50de24e90ab (patch)
treef79a5df1353af58c671c58a4eaa7339d7ba80461 /fs/f2fs/inode.c
parent369a708c2a6557fabd409cf17a03db271c54931a (diff)
downloadlinux-d4686d56ec912d55fd8a9d6d509de50de24e90ab.tar.bz2
f2fs: avoid balanc_fs during evict_inode
1. Background Previously, if f2fs tries to move data blocks of an *evicting* inode during the cleaning process, it stops the process incompletely and then restarts the whole process, since it needs a locked inode to grab victim data pages in its address space. In order to get a locked inode, iget_locked() by f2fs_iget() is normally used, but, it waits if the inode is on freeing. So, here is a deadlock scenario. 1. f2fs_evict_inode() <- inode "A" 2. f2fs_balance_fs() 3. f2fs_gc() 4. gc_data_segment() 5. f2fs_iget() <- inode "A" too! If step #1 and #5 treat a same inode "A", step #5 would fall into deadlock since the inode "A" is on freeing. In order to resolve this, f2fs_iget_nowait() which skips __wait_on_freeing_inode() was introduced in step #5, and stops f2fs_gc() to complete f2fs_evict_inode(). 1. f2fs_evict_inode() <- inode "A" 2. f2fs_balance_fs() 3. f2fs_gc() 4. gc_data_segment() 5. f2fs_iget_nowait() <- inode "A", then stop f2fs_gc() w/ -ENOENT 2. Problem and Solution In the above scenario, however, f2fs cannot finish f2fs_evict_inode() only if: o there are not enough free sections, and o f2fs_gc() tries to move data blocks of the *evicting* inode repeatedly. So, the final solution is to use f2fs_iget() and remove f2fs_balance_fs() in f2fs_evict_inode(). The f2fs_evict_inode() actually truncates all the data and node blocks, which means that it doesn't produce any dirty node pages accordingly. So, we don't need to do f2fs_balance_fs() in practical. Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
Diffstat (limited to 'fs/f2fs/inode.c')
-rw-r--r--fs/f2fs/inode.c33
1 files changed, 0 insertions, 33 deletions
diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
index 62433c63e2db..ddae412d30c8 100644
--- a/fs/f2fs/inode.c
+++ b/fs/f2fs/inode.c
@@ -16,11 +16,6 @@
#include "f2fs.h"
#include "node.h"
-struct f2fs_iget_args {
- u64 ino;
- int on_free;
-};
-
void f2fs_set_inode_flags(struct inode *inode)
{
unsigned int flags = F2FS_I(inode)->i_flags;
@@ -40,34 +35,6 @@ void f2fs_set_inode_flags(struct inode *inode)
inode->i_flags |= S_DIRSYNC;
}
-static int f2fs_iget_test(struct inode *inode, void *data)
-{
- struct f2fs_iget_args *args = data;
-
- if (inode->i_ino != args->ino)
- return 0;
- if (inode->i_state & (I_FREEING | I_WILL_FREE)) {
- args->on_free = 1;
- return 0;
- }
- return 1;
-}
-
-struct inode *f2fs_iget_nowait(struct super_block *sb, unsigned long ino)
-{
- struct f2fs_iget_args args = {
- .ino = ino,
- .on_free = 0
- };
- struct inode *inode = ilookup5(sb, ino, f2fs_iget_test, &args);
-
- if (inode)
- return inode;
- if (!args.on_free)
- return f2fs_iget(sb, ino);
- return ERR_PTR(-ENOENT);
-}
-
static int do_read_inode(struct inode *inode)
{
struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);