ext4: fix __ext4_new_inode() journal credits calculation

ea_inode feature allows creating extended attributes that are up to
64k in size. Update __ext4_new_inode() to pick increased credit limits.

To avoid overallocating too many journal credits, update
__ext4_xattr_set_credits() to make a distinction between xattr create
vs update. This helps __ext4_new_inode() because all attributes are
known to be new, so we can save credits that are normally needed to
delete old values.

Also, have fscrypt specify its maximum context size so that we don't
end up allocating credits for 64k size.

Signed-off-by: Tahsin Erdogan <tahsin@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c
index 210976e7a269ff0760cf81f6b1975632f9876862..94becf5a151902e23ab1986d9ff201de60a0ad33 100644 (file)
--- a/fs/crypto/policy.c
+++ b/fs/crypto/policy.c
@@ -260,6 +260,7 @@ int fscrypt_inherit_context(struct inode *parent, struct inode *child,
        memcpy(ctx.master_key_descriptor, ci->ci_master_key,
               FS_KEY_DESCRIPTOR_SIZE);
        get_random_bytes(ctx.nonce, FS_KEY_DERIVATION_NONCE_SIZE);
+       BUILD_BUG_ON(sizeof(ctx) != FSCRYPT_SET_CONTEXT_MAX_SIZE);
        res = parent->i_sb->s_cop->set_context(child, &ctx,
                                                sizeof(ctx), fs_data);
        if (res)

diff --git a/fs/ext4/acl.c b/fs/ext4/acl.c
index 8db03e5c78bcac550f01d4451d05f21ccf58d9bb..09441ae07a5be9de1f18cdc01d896808ba1e02be 100644 (file)
--- a/fs/ext4/acl.c
+++ b/fs/ext4/acl.c
@@ -183,7 +183,7 @@ ext4_get_acl(struct inode *inode, int type)
  */
 static int
 __ext4_set_acl(handle_t *handle, struct inode *inode, int type,
-            struct posix_acl *acl)
+            struct posix_acl *acl, int xattr_flags)
 {
        int name_index;
        void *value = NULL;
@@ -218,7 +218,7 @@ __ext4_set_acl(handle_t *handle, struct inode *inode, int type,
        }
 
        error = ext4_xattr_set_handle(handle, inode, name_index, "",
-                                     value, size, 0);
+                                     value, size, xattr_flags);
 
        kfree(value);
        if (!error)
@@ -238,7 +238,8 @@ ext4_set_acl(struct inode *inode, struct posix_acl *acl, int type)
        if (error)
                return error;
 retry:
-       error = ext4_xattr_set_credits(inode, acl_size, &credits);
+       error = ext4_xattr_set_credits(inode, acl_size, false /* is_create */,
+                                      &credits);
        if (error)
                return error;
 
@@ -246,7 +247,7 @@ retry:
        if (IS_ERR(handle))
                return PTR_ERR(handle);
 
-       error = __ext4_set_acl(handle, inode, type, acl);
+       error = __ext4_set_acl(handle, inode, type, acl, 0 /* xattr_flags */);
        ext4_journal_stop(handle);
        if (error == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
                goto retry;
@@ -271,13 +272,13 @@ ext4_init_acl(handle_t *handle, struct inode *inode, struct inode *dir)
 
        if (default_acl) {
                error = __ext4_set_acl(handle, inode, ACL_TYPE_DEFAULT,
-                                      default_acl);
+                                      default_acl, XATTR_CREATE);
                posix_acl_release(default_acl);
        }
        if (acl) {
                if (!error)
                        error = __ext4_set_acl(handle, inode, ACL_TYPE_ACCESS,
-                                              acl);
+                                              acl, XATTR_CREATE);
                posix_acl_release(acl);
        }
        return error;

diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 0c79e3efcaf720965c06a103aabab4cc26c78a08..507bfb3344d41d1cc857022e61eb7c09ab184231 100644 (file)
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -766,11 +766,13 @@ struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir,
        if (!dir || !dir->i_nlink)
                return ERR_PTR(-EPERM);
 
-       if (unlikely(ext4_forced_shutdown(EXT4_SB(dir->i_sb))))
+       sb = dir->i_sb;
+       sbi = EXT4_SB(sb);
+
+       if (unlikely(ext4_forced_shutdown(sbi)))
                return ERR_PTR(-EIO);
 
-       if ((ext4_encrypted_inode(dir) ||
-            DUMMY_ENCRYPTION_ENABLED(EXT4_SB(dir->i_sb))) &&
+       if ((ext4_encrypted_inode(dir) || DUMMY_ENCRYPTION_ENABLED(sbi)) &&
            (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)) &&
            !(i_flags & EXT4_EA_INODE_FL)) {
                err = fscrypt_get_encryption_info(dir);
@@ -778,19 +780,55 @@ struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir,
                        return ERR_PTR(err);
                if (!fscrypt_has_encryption_key(dir))
                        return ERR_PTR(-ENOKEY);
-               if (!handle)
-                       nblocks += EXT4_DATA_TRANS_BLOCKS(dir->i_sb);
                encrypt = 1;
        }
 
-       sb = dir->i_sb;
+       if (!handle && sbi->s_journal && !(i_flags & EXT4_EA_INODE_FL)) {
+#ifdef CONFIG_EXT4_FS_POSIX_ACL
+               struct posix_acl *p = get_acl(dir, ACL_TYPE_DEFAULT);
+
+               if (p) {
+                       int acl_size = p->a_count * sizeof(ext4_acl_entry);
+
+                       nblocks += (S_ISDIR(mode) ? 2 : 1) *
+                               __ext4_xattr_set_credits(sb, NULL /* inode */,
+                                       NULL /* block_bh */, acl_size,
+                                       true /* is_create */);
+                       posix_acl_release(p);
+               }
+#endif
+
+#ifdef CONFIG_SECURITY
+               {
+                       int num_security_xattrs = 1;
+
+#ifdef CONFIG_INTEGRITY
+                       num_security_xattrs++;
+#endif
+                       /*
+                        * We assume that security xattrs are never
+                        * more than 1k.  In practice they are under
+                        * 128 bytes.
+                        */
+                       nblocks += num_security_xattrs *
+                               __ext4_xattr_set_credits(sb, NULL /* inode */,
+                                       NULL /* block_bh */, 1024,
+                                       true /* is_create */);
+               }
+#endif
+               if (encrypt)
+                       nblocks += __ext4_xattr_set_credits(sb,
+                                       NULL /* inode */, NULL /* block_bh */,
+                                       FSCRYPT_SET_CONTEXT_MAX_SIZE,
+                                       true /* is_create */);
+       }
+
        ngroups = ext4_get_groups_count(sb);
        trace_ext4_request_inode(dir, mode);
        inode = new_inode(sb);
        if (!inode)
                return ERR_PTR(-ENOMEM);
        ei = EXT4_I(inode);
-       sbi = EXT4_SB(sb);
 
        /*
         * Initialize owners and quota early so that we don't have to account

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 56c971807df5bc43f98f2abce621a64524b0b44f..f666042a3d5828e970e67473ce9c92646fbc1be2 100644 (file)
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1194,7 +1194,8 @@ static int ext4_set_context(struct inode *inode, const void *ctx, size_t len,
        if (res)
                return res;
 retry:
-       res = ext4_xattr_set_credits(inode, len, &credits);
+       res = ext4_xattr_set_credits(inode, len, false /* is_create */,
+                                    &credits);
        if (res)
                return res;
 

diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index 34fa37e7744c5cb10545612267f8e5907b12ad9f..cff4f41ced612d9b0f344be66a17e434981f8861 100644 (file)
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -830,11 +830,10 @@ static void ext4_xattr_inode_free_quota(struct inode *inode, size_t len)
        dquot_free_inode(inode);
 }
 
-static int __ext4_xattr_set_credits(struct inode *inode,
-                                   struct buffer_head *block_bh,
-                                   size_t value_len)
+int __ext4_xattr_set_credits(struct super_block *sb, struct inode *inode,
+                            struct buffer_head *block_bh, size_t value_len,
+                            bool is_create)
 {
-       struct super_block *sb = inode->i_sb;
        int credits;
        int blocks;
 
@@ -860,7 +859,7 @@ static int __ext4_xattr_set_credits(struct inode *inode,
         * In case of inline data, we may push out the data to a block,
         * so we need to reserve credits for this eventuality
         */
-       if (ext4_has_inline_data(inode))
+       if (inode && ext4_has_inline_data(inode))
                credits += ext4_writepage_trans_blocks(inode) + 1;
 
        /* We are done if ea_inode feature is not enabled. */
@@ -882,19 +881,23 @@ static int __ext4_xattr_set_credits(struct inode *inode,
        /* Blocks themselves. */
        credits += blocks;
 
-       /* Dereference ea_inode holding old xattr value.
-        * Old ea_inode, inode map, block bitmap, group descriptor.
-        */
-       credits += 4;
+       if (!is_create) {
+               /* Dereference ea_inode holding old xattr value.
+                * Old ea_inode, inode map, block bitmap, group descriptor.
+                */
+               credits += 4;
 
-       /* Data blocks for old ea_inode. */
-       blocks = XATTR_SIZE_MAX >> sb->s_blocksize_bits;
+               /* Data blocks for old ea_inode. */
+               blocks = XATTR_SIZE_MAX >> sb->s_blocksize_bits;
 
-       /* Indirection block or one level of extent tree for old ea_inode. */
-       blocks += 1;
+               /* Indirection block or one level of extent tree for old
+                * ea_inode.
+                */
+               blocks += 1;
 
-       /* Block bitmap and group descriptor updates for each block. */
-       credits += blocks * 2;
+               /* Block bitmap and group descriptor updates for each block. */
+               credits += blocks * 2;
+       }
 
        /* We may need to clone the existing xattr block in which case we need
         * to increment ref counts for existing ea_inodes referenced by it.
@@ -2263,7 +2266,9 @@ ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
                        goto cleanup;
                }
 
-               credits = __ext4_xattr_set_credits(inode, bh, value_len);
+               credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
+                                                  value_len,
+                                                  flags & XATTR_CREATE);
                brelse(bh);
 
                if (!ext4_handle_has_enough_credits(handle, credits)) {
@@ -2370,7 +2375,8 @@ cleanup:
        return error;
 }
 
-int ext4_xattr_set_credits(struct inode *inode, size_t value_len, int *credits)
+int ext4_xattr_set_credits(struct inode *inode, size_t value_len,
+                          bool is_create, int *credits)
 {
        struct buffer_head *bh;
        int err;
@@ -2386,7 +2392,8 @@ int ext4_xattr_set_credits(struct inode *inode, size_t value_len, int *credits)
        if (IS_ERR(bh)) {
                err = PTR_ERR(bh);
        } else {
-               *credits = __ext4_xattr_set_credits(inode, bh, value_len);
+               *credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
+                                                   value_len, is_create);
                brelse(bh);
                err = 0;
        }
@@ -2417,7 +2424,8 @@ ext4_xattr_set(struct inode *inode, int name_index, const char *name,
                return error;
 
 retry:
-       error = ext4_xattr_set_credits(inode, value_len, &credits);
+       error = ext4_xattr_set_credits(inode, value_len, flags & XATTR_CREATE,
+                                      &credits);
        if (error)
                return error;
 

diff --git a/fs/ext4/xattr.h b/fs/ext4/xattr.h
index 26119a67c8c32d03a79df865b6bc04873e9dfecc..0d2dde1fa87a1a4cde68188980546225daf4f671 100644 (file)
--- a/fs/ext4/xattr.h
+++ b/fs/ext4/xattr.h
@@ -153,7 +153,10 @@ extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t);
 extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
 extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);
 extern int ext4_xattr_set_credits(struct inode *inode, size_t value_len,
-                                 int *credits);
+                                 bool is_create, int *credits);
+extern int __ext4_xattr_set_credits(struct super_block *sb, struct inode *inode,
+                               struct buffer_head *block_bh, size_t value_len,
+                               bool is_create);
 
 extern int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
                                   struct ext4_xattr_inode_array **array,

diff --git a/include/linux/fscrypt_common.h b/include/linux/fscrypt_common.h
index 0a30c106c1e535188637d7947a74f77c933968a1..82beaf70e7e2118875dbdb9a14a334f5a9a0c81f 100644 (file)
--- a/include/linux/fscrypt_common.h
+++ b/include/linux/fscrypt_common.h
@@ -83,6 +83,9 @@ struct fscrypt_operations {
        unsigned (*max_namelen)(struct inode *);
 };
 
+/* Maximum value for the third parameter of fscrypt_operations.set_context(). */
+#define FSCRYPT_SET_CONTEXT_MAX_SIZE   28
+
 static inline bool fscrypt_dummy_context_enabled(struct inode *inode)
 {
        if (inode->i_sb->s_cop->dummy_context &&