Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=5a25403175b8a945e93fc9c64ae9cf54f5730add
Commit: 5a25403175b8a945e93fc9c64ae9cf54f5730add
Parent: ce76fd30ce98cdaeb38dca0dfbb3fa6d2801c5ce
Author: Mark Fasheh <[EMAIL PROTECTED]>
AuthorDate: Fri Jul 20 12:56:16 2007 -0700
Committer: Mark Fasheh <[EMAIL PROTECTED]>
CommitDate: Thu Aug 9 17:25:49 2007 -0700
ocfs2: Fix max offset calculations
ocfs2_max_file_offset() was over-estimating the largest file size for
several cases. This wasn't really a problem before, but now that we support
sparse files, it needs to be more accurate.
Signed-off-by: Mark Fasheh <[EMAIL PROTECTED]>
---
fs/ocfs2/super.c | 68 +++++++++++++++++++++++++++++++----------------------
1 files changed, 40 insertions(+), 28 deletions(-)
diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
index a100b48..c3c89e2 100644
--- a/fs/ocfs2/super.c
+++ b/fs/ocfs2/super.c
@@ -316,39 +316,51 @@ static void ocfs2_destroy_inode(struct inode *inode)
kmem_cache_free(ocfs2_inode_cachep, OCFS2_I(inode));
}
-/* From xfs_super.c:xfs_max_file_offset
- * Copyright (c) 2000-2004 Silicon Graphics, Inc.
- */
-static unsigned long long ocfs2_max_file_offset(unsigned int blockshift)
+static unsigned long long ocfs2_max_file_offset(unsigned int bbits,
+ unsigned int cbits)
{
- unsigned int pagefactor = 1;
- unsigned int bitshift = BITS_PER_LONG - 1;
-
- /* Figure out maximum filesize, on Linux this can depend on
- * the filesystem blocksize (on 32 bit platforms).
- * __block_prepare_write does this in an [unsigned] long...
- * page->index << (PAGE_CACHE_SHIFT - bbits)
- * So, for page sized blocks (4K on 32 bit platforms),
- * this wraps at around 8Tb (hence MAX_LFS_FILESIZE which is
- * (((u64)PAGE_CACHE_SIZE << (BITS_PER_LONG-1))-1)
- * but for smaller blocksizes it is less (bbits = log2 bsize).
- * Note1: get_block_t takes a long (implicit cast from above)
- * Note2: The Large Block Device (LBD and HAVE_SECTOR_T) patch
- * can optionally convert the [unsigned] long from above into
- * an [unsigned] long long.
+ unsigned int bytes = 1 << cbits;
+ unsigned int trim = bytes;
+ unsigned int bitshift = 32;
+
+ /*
+ * i_size and all block offsets in ocfs2 are always 64 bits
+ * wide. i_clusters is 32 bits, in cluster-sized units. So on
+ * 64 bit platforms, cluster size will be the limiting factor.
*/
#if BITS_PER_LONG == 32
# if defined(CONFIG_LBD)
BUILD_BUG_ON(sizeof(sector_t) != 8);
- pagefactor = PAGE_CACHE_SIZE;
- bitshift = BITS_PER_LONG;
+ /*
+ * We might be limited by page cache size.
+ */
+ if (bytes > PAGE_CACHE_SIZE) {
+ bytes = PAGE_CACHE_SIZE;
+ trim = 1;
+ /*
+ * Shift by 31 here so that we don't get larger than
+ * MAX_LFS_FILESIZE
+ */
+ bitshift = 31;
+ }
# else
- pagefactor = PAGE_CACHE_SIZE >> (PAGE_CACHE_SHIFT - blockshift);
+ /*
+ * We are limited by the size of sector_t. Use block size, as
+ * that's what we expose to the VFS.
+ */
+ bytes = 1 << bbits;
+ trim = 1;
+ bitshift = 31;
# endif
#endif
- return (((unsigned long long)pagefactor) << bitshift) - 1;
+ /*
+ * Trim by a whole cluster when we can actually approach the
+ * on-disk limits. Otherwise we can overflow i_clusters when
+ * an extent start is at the max offset.
+ */
+ return (((unsigned long long)bytes) << bitshift) - trim;
}
static int ocfs2_remount(struct super_block *sb, int *flags, char *data)
@@ -1259,8 +1271,8 @@ static int ocfs2_initialize_super(struct super_block *sb,
int sector_size)
{
int status = 0;
- int i;
- struct ocfs2_dinode *di = NULL;
+ int i, cbits, bbits;
+ struct ocfs2_dinode *di = (struct ocfs2_dinode *)bh->b_data;
struct inode *inode = NULL;
struct buffer_head *bitmap_bh = NULL;
struct ocfs2_journal *journal;
@@ -1281,7 +1293,9 @@ static int ocfs2_initialize_super(struct super_block *sb,
sb->s_export_op = &ocfs2_export_ops;
sb->s_flags |= MS_NOATIME;
/* this is needed to support O_LARGEFILE */
- sb->s_maxbytes = ocfs2_max_file_offset(sb->s_blocksize_bits);
+ cbits = le32_to_cpu(di->id2.i_super.s_clustersize_bits);
+ bbits = le32_to_cpu(di->id2.i_super.s_blocksize_bits);
+ sb->s_maxbytes = ocfs2_max_file_offset(bbits, cbits);
osb->sb = sb;
/* Save off for ocfs2_rw_direct */
@@ -1341,8 +1355,6 @@ static int ocfs2_initialize_super(struct super_block *sb,
goto bail;
}
- di = (struct ocfs2_dinode *)bh->b_data;
-
osb->max_slots = le16_to_cpu(di->id2.i_super.s_max_slots);
if (osb->max_slots > OCFS2_MAX_SLOTS || osb->max_slots == 0) {
mlog(ML_ERROR, "Invalid number of node slots (%u)\n",
-
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