[16/17] ext2: Variable order page cache support

clameter
2007-04-24T22:27:16Z

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[-- Type: text/plain, Size: 9904 bytes --]

This adds variable page size support. It is then possible to mount filesystems
that have a larger blocksize than the page size.

F.e. the following is possible on x86_64 and i386 that have only a 4k page
size.

mke2fs -b 16384 /dev/hdd2 <Ignore warning about too large block size>

mount /dev/hdd2 /media
ls -l /media

.... Do more things with the volume that uses a 16k page cache size on
a 4k page sized platform..

We disable mmap for higher order pages like also done for ramfs. This
is temporary until we get support for mmapping higher order pages.

Signed-off-by: Christoph Lameter <clameter@sgi.com>

---
fs/ext2/dir.c | 40 +++++++++++++++++++++++-----------------
fs/ext2/ext2.h | 1 +
fs/ext2/file.c | 18 ++++++++++++++++++
fs/ext2/inode.c | 10 ++++++++--
fs/ext2/namei.c | 10 ++++++++--
5 files changed, 58 insertions(+), 21 deletions(-)

Index: linux-2.6.21-rc7/fs/ext2/dir.c
===================================================================
--- linux-2.6.21-rc7.orig/fs/ext2/dir.c 2007-04-23 22:26:18.000000000 -0700
+++ linux-2.6.21-rc7/fs/ext2/dir.c 2007-04-23 22:27:52.000000000 -0700
@@ -44,7 +44,8 @@ static inline void ext2_put_page(struct

static inline unsigned long dir_pages(struct inode *inode)
{
- return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT;
+ return (inode->i_size+page_cache_size(inode->i_mapping)-1)>>
+ page_cache_shift(inode->i_mapping);
}

/*
@@ -55,10 +56,11 @@ static unsigned
ext2_last_byte(struct inode *inode, unsigned long page_nr)
{
unsigned last_byte = inode->i_size;
+ struct address_space *mapping = inode->i_mapping;

- last_byte -= page_nr << PAGE_CACHE_SHIFT;
- if (last_byte > PAGE_CACHE_SIZE)
- last_byte = PAGE_CACHE_SIZE;
+ last_byte -= page_nr << page_cache_shift(mapping);
+ if (last_byte > page_cache_size(mapping))
+ last_byte = page_cache_size(mapping);
return last_byte;
}

@@ -77,18 +79,19 @@ static int ext2_commit_chunk(struct page

static void ext2_check_page(struct page *page)
{
- struct inode *dir = page->mapping->host;
+ struct address_space *mapping = page->mapping;
+ struct inode *dir = mapping->host;
struct super_block *sb = dir->i_sb;
unsigned chunk_size = ext2_chunk_size(dir);
char *kaddr = page_address(page);
u32 max_inumber = le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count);
unsigned offs, rec_len;
- unsigned limit = PAGE_CACHE_SIZE;
+ unsigned limit = page_cache_size(mapping);
ext2_dirent *p;
char *error;

- if ((dir->i_size >> PAGE_CACHE_SHIFT) == page->index) {
- limit = dir->i_size & ~PAGE_CACHE_MASK;
+ if (page_cache_index(mapping, dir->i_size) == page->index) {
+ limit = page_cache_offset(mapping, dir->i_size);
if (limit & (chunk_size - 1))
goto Ebadsize;
if (!limit)
@@ -140,7 +143,7 @@ Einumber:
bad_entry:
ext2_error (sb, "ext2_check_page", "bad entry in directory #%lu: %s - "
"offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
- dir->i_ino, error, (page->index<<PAGE_CACHE_SHIFT)+offs,
+ dir->i_ino, error, page_cache_pos(mapping, page->index, offs),
(unsigned long) le32_to_cpu(p->inode),
rec_len, p->name_len);
goto fail;
@@ -149,7 +152,7 @@ Eend:
ext2_error (sb, "ext2_check_page",
"entry in directory #%lu spans the page boundary"
"offset=%lu, inode=%lu",
- dir->i_ino, (page->index<<PAGE_CACHE_SHIFT)+offs,
+ dir->i_ino, page_cache_pos(mapping, page->index, offs),
(unsigned long) le32_to_cpu(p->inode));
fail:
SetPageChecked(page);
@@ -250,8 +253,9 @@ ext2_readdir (struct file * filp, void *
loff_t pos = filp->f_pos;
struct inode *inode = filp->f_path.dentry->d_inode;
struct super_block *sb = inode->i_sb;
- unsigned int offset = pos & ~PAGE_CACHE_MASK;
- unsigned long n = pos >> PAGE_CACHE_SHIFT;
+ struct address_space *mapping = inode->i_mapping;
+ unsigned int offset = page_cache_offset(mapping, pos);
+ unsigned long n = page_cache_index(mapping, pos);
unsigned long npages = dir_pages(inode);
unsigned chunk_mask = ~(ext2_chunk_size(inode)-1);
unsigned char *types = NULL;
@@ -272,14 +276,14 @@ ext2_readdir (struct file * filp, void *
ext2_error(sb, __FUNCTION__,
"bad page in #%lu",
inode->i_ino);
- filp->f_pos += PAGE_CACHE_SIZE - offset;
+ filp->f_pos += page_cache_size(mapping) - offset;
return -EIO;
}
kaddr = page_address(page);
if (unlikely(need_revalidate)) {
if (offset) {
offset = ext2_validate_entry(kaddr, offset, chunk_mask);
- filp->f_pos = (n<<PAGE_CACHE_SHIFT) + offset;
+ filp->f_pos = page_cache_pos(mapping, n, offset);
}
filp->f_version = inode->i_version;
need_revalidate = 0;
@@ -302,7 +306,7 @@ ext2_readdir (struct file * filp, void *

offset = (char *)de - kaddr;
over = filldir(dirent, de->name, de->name_len,
- (n<<PAGE_CACHE_SHIFT) | offset,
+ page_cache_pos(mapping, n, offset),
le32_to_cpu(de->inode), d_type);
if (over) {
ext2_put_page(page);
@@ -328,6 +332,7 @@ struct ext2_dir_entry_2 * ext2_find_entr
struct dentry *dentry, struct page ** res_page)
{
const char *name = dentry->d_name.name;
+ struct address_space *mapping = dir->i_mapping;
int namelen = dentry->d_name.len;
unsigned reclen = EXT2_DIR_REC_LEN(namelen);
unsigned long start, n;
@@ -369,7 +374,7 @@ struct ext2_dir_entry_2 * ext2_find_entr
if (++n >= npages)
n = 0;
/* next page is past the blocks we've got */
- if (unlikely(n > (dir->i_blocks >> (PAGE_CACHE_SHIFT - 9)))) {
+ if (unlikely(n > (dir->i_blocks >> (page_cache_shift(mapping) - 9)))) {
ext2_error(dir->i_sb, __FUNCTION__,
"dir %lu size %lld exceeds block count %llu",
dir->i_ino, dir->i_size,
@@ -438,6 +443,7 @@ void ext2_set_link(struct inode *dir, st
int ext2_add_link (struct dentry *dentry, struct inode *inode)
{
struct inode *dir = dentry->d_parent->d_inode;
+ struct address_space *mapping = inode->i_mapping;
const char *name = dentry->d_name.name;
int namelen = dentry->d_name.len;
unsigned chunk_size = ext2_chunk_size(dir);
@@ -467,7 +473,7 @@ int ext2_add_link (struct dentry *dentry
kaddr = page_address(page);
dir_end = kaddr + ext2_last_byte(dir, n);
de = (ext2_dirent *)kaddr;
- kaddr += PAGE_CACHE_SIZE - reclen;
+ kaddr += page_cache_size(mapping) - reclen;
while ((char *)de <= kaddr) {
if ((char *)de == dir_end) {
/* We hit i_size */
Index: linux-2.6.21-rc7/fs/ext2/ext2.h
===================================================================
--- linux-2.6.21-rc7.orig/fs/ext2/ext2.h 2007-04-23 22:26:18.000000000 -0700
+++ linux-2.6.21-rc7/fs/ext2/ext2.h 2007-04-23 22:27:52.000000000 -0700
@@ -160,6 +160,7 @@ extern const struct file_operations ext2
/* file.c */
extern const struct inode_operations ext2_file_inode_operations;
extern const struct file_operations ext2_file_operations;
+extern const struct file_operations ext2_no_mmap_file_operations;
extern const struct file_operations ext2_xip_file_operations;

/* inode.c */
Index: linux-2.6.21-rc7/fs/ext2/file.c
===================================================================
--- linux-2.6.21-rc7.orig/fs/ext2/file.c 2007-04-23 22:26:18.000000000 -0700
+++ linux-2.6.21-rc7/fs/ext2/file.c 2007-04-23 22:27:52.000000000 -0700
@@ -58,6 +58,24 @@ const struct file_operations ext2_file_o
.splice_write = generic_file_splice_write,
};

+const struct file_operations ext2_no_mmap_file_operations = {
+ .llseek = generic_file_llseek,
+ .read = do_sync_read,
+ .write = do_sync_write,
+ .aio_read = generic_file_aio_read,
+ .aio_write = generic_file_aio_write,
+ .ioctl = ext2_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = ext2_compat_ioctl,
+#endif
+ .open = generic_file_open,
+ .release = ext2_release_file,
+ .fsync = ext2_sync_file,
+ .sendfile = generic_file_sendfile,
+ .splice_read = generic_file_splice_read,
+ .splice_write = generic_file_splice_write,
+};
+
#ifdef CONFIG_EXT2_FS_XIP
const struct file_operations ext2_xip_file_operations = {
.llseek = generic_file_llseek,
Index: linux-2.6.21-rc7/fs/ext2/inode.c
===================================================================
--- linux-2.6.21-rc7.orig/fs/ext2/inode.c 2007-04-23 22:26:18.000000000 -0700
+++ linux-2.6.21-rc7/fs/ext2/inode.c 2007-04-23 22:29:49.000000000 -0700
@@ -1128,10 +1128,16 @@ void ext2_read_inode (struct inode * ino
inode->i_fop = &ext2_xip_file_operations;
} else if (test_opt(inode->i_sb, NOBH)) {
inode->i_mapping->a_ops = &ext2_nobh_aops;
- inode->i_fop = &ext2_file_operations;
+ if (mapping_order(inode->i_mapping))
+ inode->i_fop = &ext2_no_mmap_file_operations;
+ else
+ inode->i_fop = &ext2_file_operations;
} else {
inode->i_mapping->a_ops = &ext2_aops;
- inode->i_fop = &ext2_file_operations;
+ if (mapping_order(inode->i_mapping))
+ inode->i_fop = &ext2_no_mmap_file_operations;
+ else
+ inode->i_fop = &ext2_file_operations;
}
} else if (S_ISDIR(inode->i_mode)) {
inode->i_op = &ext2_dir_inode_operations;
Index: linux-2.6.21-rc7/fs/ext2/namei.c
===================================================================
--- linux-2.6.21-rc7.orig/fs/ext2/namei.c 2007-04-23 22:26:18.000000000 -0700
+++ linux-2.6.21-rc7/fs/ext2/namei.c 2007-04-23 22:30:56.000000000 -0700
@@ -114,10 +114,16 @@ static int ext2_create (struct inode * d
inode->i_fop = &ext2_xip_file_operations;
} else if (test_opt(inode->i_sb, NOBH)) {
inode->i_mapping->a_ops = &ext2_nobh_aops;
- inode->i_fop = &ext2_file_operations;
+ if (mapping_order(inode->i_mapping))
+ inode->i_fop = &ext2_no_mmap_file_operations;
+ else
+ inode->i_fop = &ext2_file_operations;
} else {
inode->i_mapping->a_ops = &ext2_aops;
- inode->i_fop = &ext2_file_operations;
+ if (mapping_order(inode->i_mapping))
+ inode->i_fop = &ext2_no_mmap_file_operations;
+ else
+ inode->i_fop = &ext2_file_operations;
}
mark_inode_dirty(inode);
err = ext2_add_nondir(dentry, inode);

--