Re: [PATCH 1/8] far: remove i_alloc_sem abuse
Christoph Hellwig h...@infradead.org writes:
Add a new rw_semaphore to protect bmap against truncate. Previous
i_alloc_sem was abused for this, but it's going away in this series.
In FAT case, -i_mutex was better. But, last time I saw, shmfs was using
-i_mutex to call -bmap. So, this was chosen instead.
I'm not checking current version yet though, if shmfs had change, we can
use -i_mutex.
BTW, this patch looks good to me.
Thanks.
Signed-off-by: Christoph Hellwig h...@lst.de
Index: linux-2.6/fs/fat/inode.c
===
--- linux-2.6.orig/fs/fat/inode.c 2011-06-20 21:28:19.707963855 +0200
+++ linux-2.6/fs/fat/inode.c 2011-06-20 21:29:25.031293882 +0200
@@ -224,9 +224,9 @@ static sector_t _fat_bmap(struct address
sector_t blocknr;
/* fat_get_cluster() assumes the requested blocknr isn't truncated. */
- down_read(mapping-host-i_alloc_sem);
+ down_read(MSDOS_I(mapping-host)-truncate_lock);
blocknr = generic_block_bmap(mapping, block, fat_get_block);
- up_read(mapping-host-i_alloc_sem);
+ up_read(MSDOS_I(mapping-host)-truncate_lock);
return blocknr;
}
@@ -510,6 +510,8 @@ static struct inode *fat_alloc_inode(str
ei = kmem_cache_alloc(fat_inode_cachep, GFP_NOFS);
if (!ei)
return NULL;
+
+ init_rwsem(ei-truncate_lock);
return ei-vfs_inode;
}
Index: linux-2.6/fs/fat/fat.h
===
--- linux-2.6.orig/fs/fat/fat.h 2011-06-20 21:28:19.724630522 +0200
+++ linux-2.6/fs/fat/fat.h2011-06-20 21:29:25.034627215 +0200
@@ -109,6 +109,7 @@ struct msdos_inode_info {
int i_attrs;/* unused attribute bits */
loff_t i_pos; /* on-disk position of directory entry or 0 */
struct hlist_node i_fat_hash; /* hash by i_location */
+ struct rw_semaphore truncate_lock; /* protect bmap against truncate */
struct inode vfs_inode;
};
Index: linux-2.6/fs/fat/file.c
===
--- linux-2.6.orig/fs/fat/file.c 2011-06-20 21:28:19.744630521 +0200
+++ linux-2.6/fs/fat/file.c 2011-06-20 21:29:54.501292390 +0200
@@ -429,8 +429,10 @@ int fat_setattr(struct dentry *dentry, s
}
if (attr-ia_valid ATTR_SIZE) {
+ down_write(MSDOS_I(inode)-truncate_lock);
truncate_setsize(inode, attr-ia_size);
fat_truncate_blocks(inode, attr-ia_size);
+ up_write(MSDOS_I(inode)-truncate_lock);
}
setattr_copy(inode, attr);
--
OGAWA Hirofumi hirof...@mail.parknet.co.jp
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Re: [PATCH 1/8] far: remove i_alloc_sem abuse
OGAWA Hirofumi hirof...@mail.parknet.co.jp writes: Christoph Hellwig h...@infradead.org writes: Add a new rw_semaphore to protect bmap against truncate. Previous i_alloc_sem was abused for this, but it's going away in this series. In FAT case, -i_mutex was better. But, last time I saw, shmfs was using -i_mutex to call -bmap. So, this was chosen instead. I'm not checking current version yet though, if shmfs had change, we can use -i_mutex. It was swapfile. And unfortunately it doesn't have change. BTW, this patch looks good to me. -- OGAWA Hirofumi hirof...@mail.parknet.co.jp -- To unsubscribe from this list: send the line unsubscribe linux-btrfs in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH 1/8] far: remove i_alloc_sem abuse
On Wed, Jun 22, 2011 at 12:57:43AM +0900, OGAWA Hirofumi wrote: Christoph Hellwig h...@infradead.org writes: Add a new rw_semaphore to protect bmap against truncate. Previous i_alloc_sem was abused for this, but it's going away in this series. In FAT case, -i_mutex was better. But, last time I saw, shmfs was using -i_mutex to call -bmap. So, this was chosen instead. I'm not checking current version yet though, if shmfs had change, we can use -i_mutex. I tried that first, but it gives an instant deadlock when using a swapfile on fat. -- To unsubscribe from this list: send the line unsubscribe linux-btrfs in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
[PATCH 1/8] far: remove i_alloc_sem abuse
Add a new rw_semaphore to protect bmap against truncate. Previous
i_alloc_sem was abused for this, but it's going away in this series.
Signed-off-by: Christoph Hellwig h...@lst.de
Index: linux-2.6/fs/fat/inode.c
===
--- linux-2.6.orig/fs/fat/inode.c 2011-06-20 21:28:19.707963855 +0200
+++ linux-2.6/fs/fat/inode.c2011-06-20 21:29:25.031293882 +0200
@@ -224,9 +224,9 @@ static sector_t _fat_bmap(struct address
sector_t blocknr;
/* fat_get_cluster() assumes the requested blocknr isn't truncated. */
- down_read(mapping-host-i_alloc_sem);
+ down_read(MSDOS_I(mapping-host)-truncate_lock);
blocknr = generic_block_bmap(mapping, block, fat_get_block);
- up_read(mapping-host-i_alloc_sem);
+ up_read(MSDOS_I(mapping-host)-truncate_lock);
return blocknr;
}
@@ -510,6 +510,8 @@ static struct inode *fat_alloc_inode(str
ei = kmem_cache_alloc(fat_inode_cachep, GFP_NOFS);
if (!ei)
return NULL;
+
+ init_rwsem(ei-truncate_lock);
return ei-vfs_inode;
}
Index: linux-2.6/fs/fat/fat.h
===
--- linux-2.6.orig/fs/fat/fat.h 2011-06-20 21:28:19.724630522 +0200
+++ linux-2.6/fs/fat/fat.h 2011-06-20 21:29:25.034627215 +0200
@@ -109,6 +109,7 @@ struct msdos_inode_info {
int i_attrs;/* unused attribute bits */
loff_t i_pos; /* on-disk position of directory entry or 0 */
struct hlist_node i_fat_hash; /* hash by i_location */
+ struct rw_semaphore truncate_lock; /* protect bmap against truncate */
struct inode vfs_inode;
};
Index: linux-2.6/fs/fat/file.c
===
--- linux-2.6.orig/fs/fat/file.c2011-06-20 21:28:19.744630521 +0200
+++ linux-2.6/fs/fat/file.c 2011-06-20 21:29:54.501292390 +0200
@@ -429,8 +429,10 @@ int fat_setattr(struct dentry *dentry, s
}
if (attr-ia_valid ATTR_SIZE) {
+ down_write(MSDOS_I(inode)-truncate_lock);
truncate_setsize(inode, attr-ia_size);
fat_truncate_blocks(inode, attr-ia_size);
+ up_write(MSDOS_I(inode)-truncate_lock);
}
setattr_copy(inode, attr);
--
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