[PATCH 3/4] cachefiles: perform test on s_blocksize when opening cache file.

From: David Howells
Date: Wed Nov 04 2015 - 10:20:45 EST


From: NeilBrown <neilb@xxxxxxx>

cachefiles requires that s_blocksize in the cache is not greater than
PAGE_SIZE, and performs the check every time a block is accessed.

Move the test to the place where the file is "opened", where other
file-validity tests are performed.

Signed-off-by: NeilBrown <neilb@xxxxxxx>
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
---

fs/cachefiles/namei.c | 2 ++
fs/cachefiles/rdwr.c | 6 ------
2 files changed, 2 insertions(+), 6 deletions(-)

diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c
index fc1056f5c96a..c4b893453e0e 100644
--- a/fs/cachefiles/namei.c
+++ b/fs/cachefiles/namei.c
@@ -655,6 +655,8 @@ lookup_again:
aops = d_backing_inode(object->dentry)->i_mapping->a_ops;
if (!aops->bmap)
goto check_error;
+ if (object->dentry->d_sb->s_blocksize > PAGE_SIZE)
+ goto check_error;

object->backer = object->dentry;
} else {
diff --git a/fs/cachefiles/rdwr.c b/fs/cachefiles/rdwr.c
index 3cbb0e834694..e76c2452ac40 100644
--- a/fs/cachefiles/rdwr.c
+++ b/fs/cachefiles/rdwr.c
@@ -414,9 +414,6 @@ int cachefiles_read_or_alloc_page(struct fscache_retrieval *op,
ASSERT(inode->i_mapping->a_ops->readpages);

/* calculate the shift required to use bmap */
- if (inode->i_sb->s_blocksize > PAGE_SIZE)
- goto enobufs;
-
shift = PAGE_SHIFT - inode->i_sb->s_blocksize_bits;

op->op.flags &= FSCACHE_OP_KEEP_FLAGS;
@@ -711,9 +708,6 @@ int cachefiles_read_or_alloc_pages(struct fscache_retrieval *op,
ASSERT(inode->i_mapping->a_ops->readpages);

/* calculate the shift required to use bmap */
- if (inode->i_sb->s_blocksize > PAGE_SIZE)
- goto all_enobufs;
-
shift = PAGE_SHIFT - inode->i_sb->s_blocksize_bits;

pagevec_init(&pagevec, 0);

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