ext4: Support large files

This patch converts ext4_inode i_blocks to represent total
blocks occupied by the inode in file system block size.
Earlier the variable used to represent this in 512 byte
block size. This actually limited the total size of the file.

The feature is enabled transparently when we write an inode
whose i_blocks cannot be represnted as 512 byte units in a
48 bit variable.

inode flag  EXT4_HUGE_FILE_FL

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index bb89fe727bb1327cfe075493bc6f48c2e8d37e72..9cf85721d83cfbd2819d9bc8915fea0fb1818598 100644 (file)
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2671,14 +2671,20 @@ static blkcnt_t ext4_inode_blocks(struct ext4_inode *raw_inode,
                                        struct ext4_inode_info *ei)
 {
        blkcnt_t i_blocks ;
-       struct super_block *sb = ei->vfs_inode.i_sb;
+       struct inode *inode = &(ei->vfs_inode);
+       struct super_block *sb = inode->i_sb;
 
        if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
                                EXT4_FEATURE_RO_COMPAT_HUGE_FILE)) {
                /* we are using combined 48 bit field */
                i_blocks = ((u64)le16_to_cpu(raw_inode->i_blocks_high)) << 32 |
                                        le32_to_cpu(raw_inode->i_blocks_lo);
-               return i_blocks;
+               if (ei->i_flags & EXT4_HUGE_FILE_FL) {
+                       /* i_blocks represent file system block size */
+                       return i_blocks  << (inode->i_blkbits - 9);
+               } else {
+                       return i_blocks;
+               }
        } else {
                return le32_to_cpu(raw_inode->i_blocks_lo);
        }
@@ -2829,8 +2835,9 @@ static int ext4_inode_blocks_set(handle_t *handle,
                 * i_blocks can be represnted in a 32 bit variable
                 * as multiple of 512 bytes
                 */
-               raw_inode->i_blocks_lo   = cpu_to_le32((u32)i_blocks);
+               raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
                raw_inode->i_blocks_high = 0;
+               ei->i_flags &= ~EXT4_HUGE_FILE_FL;
        } else if (i_blocks <= 0xffffffffffffULL) {
                /*
                 * i_blocks can be represented in a 48 bit variable
@@ -2841,12 +2848,23 @@ static int ext4_inode_blocks_set(handle_t *handle,
                if (err)
                        goto  err_out;
                /* i_block is stored in the split  48 bit fields */
-               raw_inode->i_blocks_lo   = cpu_to_le32((u32)i_blocks);
+               raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
                raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
+               ei->i_flags &= ~EXT4_HUGE_FILE_FL;
        } else {
-               ext4_error(sb, __FUNCTION__,
-                               "Wrong inode i_blocks count  %llu\n",
-                               (unsigned long long)inode->i_blocks);
+               /*
+                * i_blocks should be represented in a 48 bit variable
+                * as multiple of  file system block size
+                */
+               err = ext4_update_rocompat_feature(handle, sb,
+                                           EXT4_FEATURE_RO_COMPAT_HUGE_FILE);
+               if (err)
+                       goto  err_out;
+               ei->i_flags |= EXT4_HUGE_FILE_FL;
+               /* i_block is stored in file system block size */
+               i_blocks = i_blocks >> (inode->i_blkbits - 9);
+               raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
+               raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
        }
 err_out:
        return err;

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 2b9dc96ec43e8ab00ce4bf409e0ca29e869eec5a..64067de70c6f34683cf751c04a168e06783dc6f6 100644 (file)
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1631,11 +1631,14 @@ static loff_t ext4_max_size(int bits)
                upper_limit >>= (bits - 9);
 
        } else {
-               /* We use 48 bit ext4_inode i_blocks */
+               /*
+                * We use 48 bit ext4_inode i_blocks
+                * With EXT4_HUGE_FILE_FL set the i_blocks
+                * represent total number of blocks in
+                * file system block size
+                */
                upper_limit = (1LL << 48) - 1;
 
-               /* total blocks in file system block size */
-               upper_limit >>= (bits - 9);
        }
 
        /* indirect blocks */

diff --git a/include/linux/ext4_fs.h b/include/linux/ext4_fs.h
index be25eca9c040cc0ba6b250b4dd2ad6aa341dd7ca..6ae91f40aaa2e74843795dc8335deff49861f9d1 100644 (file)
--- a/include/linux/ext4_fs.h
+++ b/include/linux/ext4_fs.h
@@ -178,8 +178,9 @@ struct ext4_group_desc
 #define EXT4_NOTAIL_FL                 0x00008000 /* file tail should not be merged */
 #define EXT4_DIRSYNC_FL                        0x00010000 /* dirsync behaviour (directories only) */
 #define EXT4_TOPDIR_FL                 0x00020000 /* Top of directory hierarchies*/
-#define EXT4_RESERVED_FL               0x80000000 /* reserved for ext4 lib */
+#define EXT4_HUGE_FILE_FL               0x00040000 /* Set to each huge file */
 #define EXT4_EXTENTS_FL                        0x00080000 /* Inode uses extents */
+#define EXT4_RESERVED_FL               0x80000000 /* reserved for ext4 lib */
 
 #define EXT4_FL_USER_VISIBLE           0x000BDFFF /* User visible flags */
 #define EXT4_FL_USER_MODIFIABLE                0x000380FF /* User modifiable flags */